EXTRA.9

08 Dec 1995 - 14 Feb 1998

Messages - zvezde

zvezde.1 .bata.,
Da li neko kojim slucajem zna nesto vise o kometi koja bi trebalo da se vidi golim okom (pod uslovom da je vedro) iz Beograda ovih dana ?
zvezde.2 dvesic, -> #1, .bata.
> Da li neko kojim slucajem zna nesto vise o kometi koja bi trebalo da > se vidi golim okom (pod uslovom da je vedro) iz Beograda ovih dana ? Prenosim poruku gorans-a sa Sezam Pro-a, nadam se da se nece ljutiti :)) ================================ Razonoda, Zvezde.25, gorans (10.25) Uto 12/03/1996 19:58, 6317 chr ---------------------------------------------------------------- Evo podataka o kometi HYAKUTAKE: COMET C/1996 B2 (HYAKUTAKE) The comet announced on E1041 has been re-designated as above. Brian Marsden, Central Bureau has derived the following orbital elements from 33 measures submitted to CBAT and obtained 1996 Jan 31-Feb 3: T = 1996 May 2.769 TT Peri. = 131.202 Node = 188.943 2000.0 q = 0.22432 AU Incl. = 122.639 (IAUC 6303 extract) Ephemeris by G.Hurst using EPH.EXE by Nick James: m = 5.5 + 5.0 log R + 10.0 log r Date R.A. (2000) Dec. R r Elong Mag. Motion h m o ' (AU) (AU) o "/hr P.A. 1996 Feb 2.00 14 33.06 -24 56.3 1.788 2.022 88.7 9.8 27 91 3.00 14 33.85 -24 56.4 1.755 2.006 89.5 9.7 27 90 4.00 14 34.63 -24 56.3 1.722 1.990 90.3 9.7 27 89 5.00 14 35.41 -24 56.0 1.689 1.973 91.2 9.6 26 88 6.00 14 36.18 -24 55.5 1.656 1.957 92.0 9.5 26 87 7.00 14 36.94 -24 54.9 1.623 1.941 92.9 9.4 26 86 8.00 14 37.70 -24 53.9 1.590 1.924 93.7 9.3 26 84 9.00 14 38.44 -24 52.8 1.556 1.908 94.5 9.3 25 83 10.00 14 39.18 -24 51.4 1.523 1.891 95.4 9.2 25 81 11.00 14 39.91 -24 49.7 1.490 1.874 96.2 9.1 25 80 12.00 14 40.63 -24 47.7 1.456 1.858 97.1 9.0 25 78 13.00 14 41.34 -24 45.5 1.423 1.841 98.0 8.9 25 76 14.00 14 42.04 -24 42.9 1.390 1.824 98.8 8.8 25 74 15.00 14 42.73 -24 39.9 1.356 1.807 99.7 8.7 25 72 16.00 14 43.40 -24 36.6 1.323 1.790 100.6 8.6 25 69 17.00 14 44.07 -24 32.9 1.289 1.773 101.4 8.5 25 67 18.00 14 44.73 -24 28.7 1.256 1.756 102.3 8.4 25 64 19.00 14 45.37 -24 24.1 1.222 1.739 103.2 8.3 25 61 20.00 14 46.00 -24 18.9 1.189 1.722 104.1 8.2 25 58 21.00 14 46.61 -24 13.3 1.156 1.704 105.0 8.1 26 55 22.00 14 47.21 -24 7.0 1.122 1.687 105.9 8.0 26 51 23.00 14 47.80 -24 0.1 1.089 1.669 106.8 7.9 27 48 24.00 14 48.37 -23 52.5 1.055 1.652 107.7 7.8 28 44 25.00 14 48.92 -23 44.1 1.022 1.634 108.7 7.7 29 41 26.00 14 49.46 -23 34.9 0.988 1.617 109.6 7.6 30 37 27.00 14 49.98 -23 24.8 0.955 1.599 110.5 7.4 32 34 28.00 14 50.48 -23 13.6 0.922 1.581 111.5 7.3 34 30 29.00 14 50.96 -23 1.4 0.888 1.563 112.4 7.2 36 27 1996 Mar 1.00 14 51.43 -22 47.9 0.855 1.545 113.4 7.0 39 24 2.00 14 51.86 -22 33.0 0.822 1.527 114.4 6.9 42 21 3.00 14 52.28 -22 16.6 0.789 1.508 115.4 6.8 45 18 4.00 14 52.67 -21 58.4 0.755 1.490 116.4 6.6 49 16 5.00 14 53.04 -21 38.3 0.722 1.472 117.4 6.5 54 13 6.00 14 53.37 -21 15.9 0.689 1.453 118.5 6.3 60 11 7.00 14 53.68 -20 51.0 0.656 1.435 119.6 6.2 66 9 8.00 14 53.95 -20 23.1 0.623 1.416 120.6 6.0 74 7 9.00 14 54.18 -19 51.8 0.590 1.397 121.8 5.8 83 5 10.00 14 54.38 -19 16.4 0.558 1.378 122.9 5.6 94 4 11.00 14 54.52 -18 36.4 0.525 1.359 124.1 5.4 106 2 12.00 14 54.61 -17 50.7 0.493 1.340 125.3 5.2 121 1 13.00 14 54.65 -16 58.2 0.460 1.321 126.5 5.0 140 0 14.00 14 54.61 -15 57.5 0.428 1.301 127.8 4.8 162 359 15.00 14 54.49 -14 46.6 0.396 1.282 129.2 4.6 190 358 16.00 14 54.27 -13 23.0 0.364 1.262 130.6 4.3 226 358 17.00 14 53.94 -11 43.2 0.333 1.243 132.0 4.1 271 357 18.00 14 53.46 -9 42.5 0.302 1.223 133.5 3.8 331 356 19.00 14 52.79 -7 13.9 0.271 1.203 135.1 3.5 410 356 20.00 14 51.88 -4 7.9 0.241 1.183 136.6 3.1 518 356 21.00 14 50.63 -0 10.2 0.212 1.163 138.0 2.8 668 355 22.00 14 48.91 +5 0.5 0.185 1.142 139.0 2.4 882 355 23.00 14 46.46 +11 55.0 0.159 1.122 139.0 2.0 1185 355 24.00 14 42.83 +21 14.6 0.137 1.101 137.0 1.6 1602 355 25.00 14 37.05 +33 40.7 0.120 1.080 131.6 1.2 2103 354 26.00 14 26.64 +49 13.3 0.110 1.059 121.8 1.0 2516 352 27.00 14 2.94 +66 9.6 0.109 1.038 109.0 0.9 2563 348 28.00 12 28.32 +80 59.2 0.118 1.017 96.0 0.9 2171 328 29.00 5 44.40 +82 17.4 0.134 0.996 85.0 1.1 1761 228 30.00 4 5.86 +73 47.4 0.156 0.974 76.5 1.3 1275 200 31.00 3 41.52 +66 51.5 0.181 0.953 70.0 1.6 947 194 1996 Apr 1.00 3 30.75 +61 33.9 0.208 0.931 65.0 1.8 717 191 2.00 3 24.64 +57 28.7 0.236 0.909 60.9 1.9 556 190 3.00 3 20.65 +54 15.5 0.265 0.886 57.6 2.1 442 190 4.00 3 17.79 +51 39.9 0.295 0.864 54.7 2.2 359 189 5.00 3 15.58 +49 31.9 0.326 0.841 52.2 2.3 298 189 6.00 3 13.79 +47 44.8 0.356 0.819 50.0 2.4 252 190 7.00 3 12.26 +46 13.5 0.387 0.796 48.0 2.4 216 190 8.00 3 10.91 +44 54.4 0.419 0.772 46.1 2.5 189 190 9.00 3 9.67 +43 45.0 0.450 0.749 44.3 2.5 168 191 10.00 3 8.50 +42 43.1 0.482 0.725 42.7 2.5 151 192 As observers will note the comet has every prospect of becoming a naked eye object during March as it makes a close approach to the Earth.(1996 Mar 27, 0.11AU). In the latter part of March it is also extremely well placed for observation from northern hemisphere latitudes. Whilst detailed plans are already being drawn up on a worldwide basis for the study of Comet C/1995 O1 (Hale-Bopp), it now appears the Comet C/1996 B2 could become an even brighter and better placed object and both comets should present an excellent opportunity for observers who should begin preparations as soon as possible. The above ephemeris is highly uncertain, especially in late March but should assist with planning observations. ------------------------------------------------------------------ Toliko za sad... -------------------------------------------------10.25 -- I od mene :)
zvezde.3 nothingman,
Zna li neko da li se u Bgdu ili u Srbiji mogu pronaci prodavnice koje se bave prodajom Teleskopa i sl. stvari?
zvezde.4 nenad, -> #3, nothingman
> Zna li neko da li se u Bgdu ili u Srbiji mogu pronaci prodavnice koje > se bave prodajom Teleskopa i sl. stvari? Najbolje je da se raspitaš u Astronomskom društvu "Ruđer Bošković" u Narodnoj opservatoriji na Kalemegdanu. Potraži Milana Jeličića, reci slobodno da sam te ja uputio.
zvezde.5 .bata., -> #4, nenad
>> Zna li neko da li se u Bgdu ili u Srbiji mogu pronaci >> prodavnice koje se bave prodajom Teleskopa i sl. stvari? U Beogradu mozes kupiti teleskop samo ako nadjes nekog ko bi ti prodao svoj polovan (naravno kupljen u inostranstvu) ili ako nagovoris nekog da ti ga iz inostranstva donese. > Najbolje je da se raspitas u Astronomskom drustvu "Ruder > Boskovic" u Narodnoj opservatoriji na Kalemegdanu. Potrazi Bojim se da su oni van svih svetskih tokova i da ce te belo pogledati. > Potrazi > Milana Jelicica, reci slobodno da sam te ja uputio. Do Mice se lako dolazi i bez ikakve preporuke, ali na zalost od njega mozezs saznati samo najnovije traceve o kalemegdanskim homoseksualcima ;( Oni su ti od slabe pomoci... :( Ako bi bas da probas i kod njih evo ti br. tel. 624605. - najbolje je zvati petkom i subotom popodne (od 16-22) Pokusaj da odes na zvezdaru (pod glupim nazivom Astronomska opservatorija) i uz malo srece (to znaci ako zateknes nekog normalnog i budes dovoljno uporan) mozda ti podje za rukom da do nekog izvora i dodjes. Pokusaj da se javis na br. tel. 401320 i mozes traziti bilo koga od osoblja (izbegni bibliotekarke :) ) ako uspes da uhvatis probaj da davis Luku Ch. Popovica, Dimitrijevica, ... ima puno entuzijasta.
zvezde.6 nenad, -> #5, .bata.
> U Beogradu mozes kupiti teleskop samo ako nadjes nekog ko bi ti > prodao svoj polovan (naravno kupljen u inostranstvu) ili ako nagovoris > nekog da ti ga iz inostranstva donese. ... ili ako ga sam napraviš... ako znaš. :) > Bojim se da su oni van svih svetskih tokova i da ce te belo pogledati. Za informacije o pravljenju i nabavci teleskopa nije potrebno biti u svetskim tokovima. Tu se ništa značajno nije promenilo poslednjih 50 godina, naročito ne u klasi aparata koji tebe zanimaju. > Luku Ch. Popovica, Dimitrijevica, ... ima puno entuzijasta. Isti ljudi se mogu pronaći i na Narodnoj opservatoriji. Nju sam preporučio jer je lakše do nje doći, spremniji su da ti pomognu, daju neku adresu na koju možeš da se obratiš. Tačno je da se do Miće Jeličića može doći i bez "preporuke", ali ona ume da pomogne. :)
zvezde.7 .bata., -> #6, nenad
>... ili ako ga sam napravis... ako znas. :) Sve jedno je. Ondaaa morres socivaaaa ili ogledala da nabavljas (togaa kod nas opet nema), a i ako te je malo vise zanimala optika verovatno znas da su sistemi za korkciju svih mogucih aberacija veoma komplikovani... >poslednjih 50 godina, narocito ne u klasi aparata koji tebe >zanimaju. O kolikom teleskopu (durbinu) se ovde prica? (ako ne znas opticku moc onda reci bar koliko para si spreeman da ulozis u to) Tako ce biti mnogo lakse prporuciti bilo sta konkretno...
zvezde.8 vstan,
Na danasnji dan pre 35 godina poleteo prvi covek u kosmos, vazduhoplovni major Jurij Gagarin. Slava mu !
zvezde.10 marija,
Ima li neko efemeride za Hale-Bopp kometu? Marija
zvezde.11 zormi, -> #10, marija
* Ima li neko efemeride za Hale-Bopp kometu? Čuo da će biti vidljiva krajem juna, ali efemeride nemam.
zvezde.12 .andrew, -> #10, marija
Marija, verovatno cemo uskoro dobiti na NO te efemeride te tako se ne brini ! A ako treba pokusacu nekako da ih skinem sa NASSE cU
zvezde.13 .andrew,
ZANIMA LI VAS ASTRONOMIJA ILI MISTIKA ? ZA TO POSTOJE GRUPE : ASTRONOMIJA I XFILES ! AKO STE ZAINTERESOVANI MAJLUJ TE MI !!
zvezde.14 nenad,
Dva ruska astronauta će na stanici Mir provesti bar 40 dana više nego što je planirano jer trenutno Rusi nemaju novca da izvrše spuštanje. Btw, srećno novo leto, kako smo proveli najkraću noć u godini? :)
zvezde.15 .andrew, -> #14, nenad
Hvala, i tebi srecno leto ! Inace sam proveo na NO tj. Narodna Opservatorija ;) cU
zvezde.16 mango, -> #14, nenad
> Btw, srecno novo leto, kako smo proveli najkracu noc u godini? :) Ludo, burazere, ludo;) (hint: crtac sa pevcom Sofronijem:)
zvezde.17 dr.s, -> #14, nenad
/* Btw, srecno novo leto, kako smo proveli najkracu noc u godini? :) Za udzbennikom... :( :)))))
zvezde.18 micotakis,
Da li sam pogrešio mesto ili se ovde priča o Astrologiji? Ili se ovde isključivo bavi astronomijom? Ako sam na pravom mestu, interesuje me da li se neko profesionalno bavi astrologijom, ili barem amaterski, ali da zna ponešto, a ne samo da čita horskop u novinama. EMPIRE
zvezde.19 ilazarevic, -> #18, micotakis
> Ili se ovde isključivo bavi astronomijom? Zavisi koga pitaš. Ako pitaš mene, isključivo astronomijom.
zvezde.20 vstan, -> #18, micotakis
> Da li sam pogresio mesto ili se ovde prica o Astrologiji? > Ili se ovde iskljucivo bavi astronomijom? Pogresio si mesto. Ovde je iskljucivo AstroNOMIJA. Za ono prvo predvidjeno je Razno (ili Misterije ;)
zvezde.21 nothingman, -> #20, vstan
>> Pogresio si mesto. Ovde je iskljucivo AstroNOMIJA. Da, ali se ovde proteklih meseci nije pisalo o astronomiji.
zvezde.22 nenad, -> #634, lexus
> Mesec nema atmosferu, znači nema oblaka, znači moraju da se vide :) Već je bila rasprava o ovome pre jedno dve godine, i tada sam tvrdio (a tvrdim i dalje) da ne trebaju da se vide. Razlog je jednostavan: kamere i foto-aparati su bili fokusirani na predmete i astronaute. I u najzvezdanijoj noći kada osvetliš čoveka kreflektorom i fotografišeš ga zvezde se neće videti.
zvezde.23 vstan, -> #21, nothingman
> Da, ali se ovde proteklih meseci nije pisalo o astronomiji. Potrudicemo se :)
zvezde.24 vstan, -> #22, nenad
> Razlog je jednostavan: kamere i foto-aparati su bili fokusirani na > predmete i astronaute. I u najzvezdanijoj noci kada osvetlis > coveka kreflektorom i fotografises ga zvezde se nece videti. Pre je "problem" u onom drugom, dakle osvetljenje, a ne u fokusiranju. Pri tako velikom kontrastu nema sanse da se snime zvezde.
zvezde.25 ilazarevic, -> #22, nenad
> jednostavan: kamere i foto-aparati su bili fokusirani na predmete > i astronaute. I u najzvezdanijoj noći kada osvetliš čoveka > kreflektorom i fotografišeš ga zvezde se neće videti. Mislim da je problem u ekspoziciji. Da bi se snimile zvezde, potrebno je nekoliko sekundi.
zvezde.26 dr.s, -> #25, ilazarevic
/* Mislim da je problem u ekspoziciji. Da bi se snimile zvezde, potrebno je /* nekoliko sekundi. Pa i Habl je slikao zvezde tako da slika izgleda kao da je ekspozicija trajala dve nedelje. Drugacije nije moglo...
zvezde.27 dr.s, -> #25, ilazarevic
/* Mislim da je problem u ekspoziciji. Da bi se snimile zvezde, potrebno je /* nekoliko sekundi. HABL radi tako da ekspozicija bude dve nedelje. Toliko o snimanju zvezda i sazvezdja...
zvezde.28 vstan,
BESPLATAN KURS ASTRONOMIJE U Planetarijumu Astronomskog društva "Ruđer Bošković" započeo je dvoipomesečni besplatan kurs za ljubitelje astronomije. Svakog petka i subote u isto vreme, do sredine decembra, u bivšem amamu na Kalemegdanu (ispod crkve Ružica) održavaće se predavanja iz ciklusa "Astronomija za početnike", praćena slajdovima iz oblasti o kojima će biti reč. Na kraju kursa polagaće se ispit za buduće saradnike Narodne opservatorije. (Politika, 7.oktobar)
zvezde.29 marco, -> #28, vstan
>> U Planetarijumu Astronomskog drustva "Ruder Boskovic" >> zapoceo je dvoipomesecni besplatan kurs za ljubitelje >> astronomije. Svakog petka i subote u isto vreme, do Kad je poceo i u koje (isto) vreme?
zvezde.30 vstan, -> #29, marco
> Kad je poceo i u koje (isto) vreme? Ne bih znao odgovor. Preneo sam ceo članak iz Politike. Probaj da saznaš njihov tel. pa se raspitaj. Možeš i nas da obavestiš :)
zvezde.31 vstan, -> #29, marco
>>> U Planetarijumu Astronomskog drustva "Ruder Boskovic" >>> zapoceo je dvoipomesecni besplatan kurs za ljubitelje >>> astronomije. Svakog petka i subote u isto vreme, > > Kad je poceo i u koje (isto) vreme? Kursevi su od 17h. Sve što vas interesuje možete saznati na tel.624-605 (Narodna opservatorija Kalemegdan).
zvezde.32 vstan,
Danas je bilo pomračenje Sunca, oko 25%, od 16.50 pa do oko 17.50. Uvertira za sutrašnji smak sveta ?
zvezde.33 nenad, -> #30, vstan
>> Kad je poceo i u koje (isto) vreme? > > Ne bih znao odgovor. Preneo sam ceo članak iz Politike. Obično je počinjao početkom oktobra tako da je sada verovatno već u toku. To nije kurs u klasičnom smislu, i osim ako neko baš ne želi da polaže ispit na kraju može ponekad neobavezno otići na predavanje, tj. senasu u planetarijumu. Kurs se inače ponavlja svake jeseni i proleća, tako da ništa nije propušteno. Predavanja su (bila) dva puta nedeljno, petkom i subotom popodne, pretpostavljam da je i sada tako.
zvezde.34 haevorn, -> #32, vstan
// vstan, 12.10.96. 19:32, 114 chr // // Danas je bilo pomračenje Sunca, oko 25%, od 16.50 pa do oko // 17.50. Pa što ne reče bar tri sata ranije? :(((( btw, taj smak sveta - po kom vremenu se računa? po našem ili američkom (čuo sam da će biti između 12 i 13h ;))
zvezde.35 biber, -> #32, vstan
>> Danas je bilo pomračenje Sunca, oko 25%, od 16.50 pa do oko >> 17.50. Što ne reče ranije :( Oduvek sam voleo da gledam pomračenja. Sećam se kako sam kao klinac čadio staklo, da bih gledao kroz. :)
zvezde.36 vstan, -> #34, haevorn
> // Danas je bilo pomračenje Sunca, oko 25%, od 16.50 pa do > > Pa što ne reče bar tri sata ranije? :(((( Da nisam slučajno pogledao kroz prozor ne bih ni ja video. Danas piše da je počelo već oko 15.50. Zahvaljujući priličnoj sumaglici moglo je lepo da se gleda bez pomagala.
zvezde.37 vstan, -> #35, biber
> Što ne reče ranije :( > Oduvek sam voleo da gledam pomračenja. Sećam se kako sam kao > klinac čadio staklo, da bih gledao kroz. :) Nije bili najave u novinama, a tv ne pratim. A moglo je lepo da se prati bez ikakvih "pomagala".
zvezde.38 baker,
Izgleda da nas je ta "planeta" promasila !?
zvezde.39 mileusna, -> #35, biber
>> Što ne reče ranije :( >> Oduvek sam voleo da gledam pomračenja. Sećam se kako sam kao >> klinac čadio staklo, da bih gledao kroz. :) Ako se ne varam, 11. avgusta 1999. godine nastupiće potpuno pomračenje Sunca... Navij sat i uživaj... ;)
zvezde.40 mileusna, -> #38, baker
>> Izgleda da nas je ta "planeta" promasila !? Zamalo... ;) Pitam se samo kako je nismo videli kad je tolika, a ovaj mali tunjavi Mesec gledamo svake noći. :) Da nam tako nešto zaista predstoji, ceo svet bi znao za to... Ili bi možda krili da ne bi došlo do nereda na ulicama, a? :) BTW, postoji i film na sličnu temu, kao meteor ide na Zemlju, pa se ondak Rusi i Ameri dogovaraju da ga gađaju nuklearnim bojevim glavama pripremljenim za rat zvezda itd. Davno beše, ne sećam se detalja, ali znam da je New York najeb'o na kraju... ;) I setih se izjave Artura Klarka koji je rekao da sve što se priča o posetama vanzemaljaca nije istina. Kada se isti zaista pojave, rekao je, ceo svet će za to saznati u istom trenutku... E sad, na šta je konkretno mislio ne znam. Da li na to da će nas NASA sve obavestiti, ili jednostavno neće biti moguće sakriti tako nešto...
zvezde.41 lepiaf, -> #40, mileusna
Film se zove Meteor..... Le Piaf
zvezde.42 marco, -> #40, mileusna
>> BTW, postoji i film na slicnu temu, kao meteor ide na A i knjiga, by Arthur C. Clarke "The Hammer of God" Pisao sam matruski rad o toj knjigi :)
zvezde.43 basrak, -> #34, haevorn
> btw, taj smak sveta - po kom vremenu se računa? po našem ili > američkom (čuo sam da će biti između 12 i 13h ;)) Ko je to uopšte provalio?
zvezde.44 basrak, -> #37, vstan
>> Oduvek sam voleo da gledam pomračenja. Sećam se kako sam kao >> klinac čadio staklo, da bih gledao kroz. :) > > A moglo je lepo da se prati bez ikakvih "pomagala". Da li pomagala, tipa začađeno staklo, služe da bi se eliminisala svetlost ili zračenja štetna po oko? Jer, kad je pomračenje totalno, onda svetlost nije jaka, dapače, i može lepo da se gleda golim okom, ali je isto toliko opasno kao što je i gledanje u Sunce bez pomračenja. Zato mislim da je gornja izjava malo opasna. (?)
zvezde.45 biber, -> #44, basrak
>> Da li pomagala, tipa začađeno staklo, služe da bi se eliminisala svetlost >> ili zračenja štetna po oko? Jer, kad je pomračenje totalno, onda svetlost >> nije jaka, dapače, i može lepo da se gleda golim okom, ali je isto toliko >> opasno kao što je i gledanje u Sunce bez pomračenja. Zato mislim da je >> gornja izjava malo opasna. (?) Jedini razlog da se direktno ne gleda u Sunce je jaka svetlost. Čak je i za vreme totalnog pomračenja, tj. dok je ono još nepotpuno, svetlost izuzetno jaka.
zvezde.46 basrak, -> #45, biber
> Jedini razlog da se direktno ne gleda u Sunce je jaka > svetlost. Ja sam baš čuo suprotno. Nikako, ali nikako *ne* gledati u Sunce (čak ni kad je pomračenje totalno (i potpuno)) golim okom, tj. bez ikakvih pomagala jer je isto toliko opasno kao i gledanje u "obično" Sunce. Čak i opasnije jer zbog drastično slabije svetlosti možeš duže gledati u njega, a UV i ostala zračenja sa Sunca pi*e nesmetano. Ajd' nek' neko od kolega astronoma razreši ovu, potencijalno vrlo opasnu, dilemu...
zvezde.47 ilazarevic, -> #46, basrak
> Ajd' nek' neko od kolega astronoma razreši ovu, potencijalno vrlo > opasnu, dilemu... Da vidimo šta na tu temu kaže kolega astronom Muhamed Muminović, "Praktična astronomija". "Sunce se može vizuelno posmatrati na više načina. No, prije nego što Vam uopšte padne na pamet da ga gledate, pročitajte važno upozorenje. _Nikad ne smijete gledati direktno u Sunce, ma kako mali teleskop bio._ Toplota koja se stvara u fokusu može trajno oštetiti vid i čak izazvati sljepilo. Neki manji komercijalni refraktori sadrže u svom priboru male filtere koji se postavljaju ispred ili iza okulara. Autor knjige, iz vlastitog iskustva (a to misli i većina drugih koji se bave posmatranjima) NE PREPORUČUJE OVAKVE FILTERE. Jer, ma kako taman bio ovaj filter, ne možemo biti sigurni da li on propušta infracrvene zrake koje su razorne, a koje ne vidimo. Takođe, usljed toplote u fokusu, može da dođe do pucanja filtera kada je oko u djeliću sekunde izloženo punom bljesku i toploti Sunca. ... Veoma bezbedno možemo posmatrati Sunce pomoću specijalne "sunčeve prizme" ili penta prizme. Zbog unutrašnjih refleksija svjetlosnih zraka, na okularni dio teleskopa dolazi samo veoma mali dio ukupnog zračenja Sunca. Dovoljno je koristiti neki obični filter i posmatranje je u potpunosti bezbjedno. ..." Ovo se odnosilo na posmatranje pomoću instrumenata. Posmatranje golim okom bi trebalo da bude slično, samo je opasnost manja za par redova veličine. Što se čađavog stakla tiče, ja se ne bih usudio da ga koristim, jer kroz njega IC i UV zraci prolaze nesmetano. Naravno, ozbiljan posmatrač uvek bi napravio seriju fotografija. P.S. Priznajem da bih gledao golim okom prstenasto pomračenje, ali samo dok je u piku.
zvezde.51 sale.car,
HI! Posto vidim da je ovako 'malo' zaostala tema... Ajde neka neko za pocetak obesi efemeride za ovu godinu (jesam li se lepo odrazio ? :)) Ja sam letos gledao Jupiter sasvim lepo sa durbinom povecanja 20x. Vide se i meseci... Pozdrav...
zvezde.52 vstan,
Juče je preminuo Karl Segan.
zvezde.53 nenad, -> #52, vstan
> Juče je preminuo Karl Segan. A sutra (subota) u 15:05:54 počinje zima.
zvezde.54 fortuna,
Neka mu je vechna slava
zvezde.55 lexus, -> #53, nenad
=>> Juče je preminuo Karl Segan. => => A sutra (subota) u 15:05:54 počinje zima. Moram priznati da mi nije jasno kako uz vest o smrti Karla Segana možeš da prilepiš vest o početku zime...
zvezde.56 darth.vader, -> #55, lexus
>> Moram priznati da mi nije jasno kako uz vest o smrti >> Karla Segana mozes da prilepis vest o pocetku zime... Pa jel vidis da moze ;)
zvezde.57 pifat,
Ko još nije saznao, evo email adrese Astronomskog društva "Ru"er Bošković" i URL-a sa njegovim home page-om: email: astrorbo@eunet.yu http://solair.eunet.yu/~astrorbo
zvezde.58 nenad,
Svetska saradnja u cilju eksploatacije teleskopa razlučivosti 1000 puta veće od one koju ima Hablov teleskop. Uz poruku je i slika koja simbolizuje princip rada klastera radio teleskopa, zbog čega se za ovaj i kaže da je "tri puta veći od zemlje". LAUNCH WILL CREATE A RADIO TELESCOPE LARGER THAN EARTH NASA and the National Radio Astronomy Observatory are joining with an international consortium of space agencies to support the launch of a Japanese satellite next week that will create the largest astronomical "instrument" ever built -- a radio telescope more than two-and-a-half times the diameter of the Earth that will give astronomers their sharpest view yet of the universe. The launch of the Very Long Base Interferometry (VLBI) Space Observatory Program satellite by Japan's Institute of Space and Astronautical Science (ISAS) is scheduled for February 10 at 8:50 p.m. Pacific time (1:50 p.m. February 11, Japan time.) The satellite is part of an international collaboration led by ISAS and backed by Japan's National Astronomical Observatory; NASA's Jet Propulsion Laboratory (JPL); the National Science Foundation's National Radio Astronomy Observatory (NRAO), Socorro, NM; the Canadian Space Agency; the Australia Telescope National Facility; the European VLBI Network and the Joint Institute for Very Long Baseline Interferometry in Europe. Very long baseline interferometry is a technique used by radio astronomers to electronically link widely-separated radio telescopes together so they work as if they were a single instrument with extraordinarily sharp "vision," or resolving power. The wider the distance between telescopes, the greater the resolving power. By taking this technique into space for the first time, astronomers will approximately triple the resolving power previously available with only ground-based telescopes. The satellite system will have resolving power almost 1,000 times greater than the Hubble Space Telescope has at optical wavelengths. The satellite's resolving power is equivalent to being able to see a grain of rice in Tokyo from Los Angeles. "Using space VLBI, we can probe the cores of quasars and active galaxies, believed to be powered by super-massive black holes," said Dr. Robert Preston, project scientist for the U.S. Space Very Long Baseline Interferometry project at JPL. "Observations of cosmic masers -- naturally-occurring microwave radio amplifiers -- will tell us new things about the process of star formation and activity in the heart of other galaxies." "By the 1980s, radio astronomers were observing the universe with assemblages of radio telescopes whose resolving power was limited only by the size of the Earth. Now, through a magnificent international effort, we will be able to break this barrier and see fine details of celestial objects that are beyond the reach of a purely ground-based telescope array. We anticipate a rich harvest of new scientific knowledge from VSOP," Dr. Paul Vanden Bout, director of NRAO. In the first weeks after launch, scientists and engineers will "test the deployment of the reflecting mesh telescope in orbit, the wide-band data link from the satellite to the ground, the performance of the low noise amplifiers in orbit, and the high-precision orbit determination and attitude control necessary for VLBI observations with an orbiting telescope," according to Dr. Joel Smith, manager of the U.S. Space Very Long Baseline Interferometry project at JPL. Scientific observations are expected to begin in May. The 8-meter (26-foot) diameter orbiting radio telescope will observe celestial radio sources in concert with a number of the world's ground-based radio telescopes. The 830-kilogram (1,830- pound) satellite will be launched from ISAS's Kagoshima Space Center, at the southern tip of Kyushu, one of Japan's main islands, and will be the first launch with ISAS's new M-5 series rocket. The satellite will go into an elliptical orbit, varying between 1,000 and 20,000 kilometers (620 to 12,400 miles) above the Earth's surface. This orbit provides a wide range of distances between the satellite and ground-based telescopes, which is important for producing a high-quality image of the radio source being observed. One orbit of the Earth will take about six hours. The satellite's observations will concentrate on some of the most distant and intriguing objects in the universe, where the extremely sharp radio "vision" of the new system can provide much-needed information about a number of astronomical mysteries. For years, astronomers have known that powerful "engines" in the hearts of quasars and many galaxies are pouring out tremendous amounts of energy. They suspect that supermassive black holes, with gravitational fields so strong that not even light can escape them, lie in the centers of these "engines." However, the mechanism at work in the centers of quasars and active galaxies remains a mystery. Ground-based radio telescopes, notably NRAO's Very Long Baseline Array (VLBA), have revealed fascinating new details in recent years, and VSOP is expected to add a wealth of new information on these objects, millions or billions of light-years distant from Earth. Many of these same objects act as super-powerful particle accelerators to eject "jets" of subatomic particles at nearly the speed of light. Scientists plan to use VSOP to monitor the changes and motions in these jets to learn more about how they originate and interact with their surroundings. The satellite also will aim at regions in the sky where giant collections of water and other molecules act as natural amplifiers of radio emission much as lasers amplify light. These regions, called cosmic masers, are found in regions where new stars are forming and near the centers of galaxies. Observations can provide the detail needed to measure motions of individual maser "spots" within these regions, and provide exciting new information about the star-forming regions and the galaxies where the masers reside. In addition, high-resolution studies of cosmic masers can allow astronomers to calculate distances to them with unprecedented accuracy, and thus help resolve continuing questions about the size and age of the universe. The project is a major international undertaking, with about 40 radio telescopes from more than 15 countries having committed time to co-observe with the satellite. This includes the National Science Foundation's Very Long Baseline Array (VLBA), an array of 10 telescopes spanning the United States from Hawaii to Saint Croix; NASA's Deep Space Network sites in California, Spain, and Australia; the European VLBI Network, more than a dozen telescopes ranging from the United Kingdom to China; a Southern Hemisphere array of telescopes stretching from eastern Australia to South Africa; and Japan's network of domestic radio telescopes. In the United States, NASA is funding critical roles in the VSOP mission at both JPL and NRAO. JPL has built an array of three new tracking stations at its DSN sites in Goldstone, California; Madrid, Spain; and near Canberra, Australia. A large existing tracking station at each of these sites has also been converted to an extremely sensitive radio telescope for simultaneous observations with the satellite. JPL also is providing precision orbit determination, scientific and operational planning support to the Japanese, and advice to U.S. astronomers who wish to observe with the satellite. NRAO is building a new tracking station at Green Bank, West Virginia; contributing observing time on the VLBA array of telescopes; modifying existing data analysis hardware and software, and aiding astronomers with the analysis of the VSOP data. Much of the observational data will be processed at NRAO's facility in Socorro, NM, using the VLBA Correlator, a special-purpose high- performance computer designed to process VLBI data. VSOP is the culmination of many years of planning and work by scientists and engineers around the world. Tests using NASA's Tracking and Data Relay Satellite System (TDRSS) proved the feasibility of space VLBI in 1986. Just last year, those old data were used again to successfully test the data-reduction facilities for VSOP. JPL manages the U.S. Space Very Long Baseline Interferometry project for NASA's Office of Space Science, Washington, D.C. The VLBA, headquartered in Socorro, New Mexico, is part of the National Radio Astronomy Observatory, a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. vlbi-2.gif
zvezde.59 nenad,
New Black-Hole Evidence Astronomers from around the world braved the wintry elements to gather in Toronto, Ontario, last week. Among the hundreds of presentations was new evidence that binary star systems emitting X-rays consist of recognizable stars orbiting black holes. V404 Cygni, a binary system 10,000 light-years away, gives off X-rays as matter shed by its visible star heats up while rushing into the black hole's gravitational well. But, according to Ramesh Narayan and his colleagues, only a tiny fraction of the energy expected from this infall seems to find its way out as visible light or X-rays; the rest, they conclude, is being reabsorbed by material which then falls into the black hole. Thus their model may be showing that "event horizons" -- the one-way doors from which energy and matter can never escape -- really exist.
zvezde.60 nenad,
Europa's Eruptions At a press conference on January 17th, NASA scientists presented views of the enigmatic ice moon Europa that show features only 35 meters across -- roughly the size of a baseball diamond. The jumble of cracks and ridges seen on a global scale continues in ever-finer variation right down to the limit of resolution. More important, some of the views reveal what appear to be eruptions onto the surface from the interior. Based on their thickness, the flows were not liquid water but had the consistency of thick slush. In addition to ice volcanism, investigators can see that the surface is modified by crustal spreading in some places and a strange tectonic collapse in others. More and more evidence suggests that Europa's outer crust is thin, perhaps only a few kilometers thick in places, and that something else -- an ocean or rock-ice-water slush -- lies just out of sight below.
zvezde.61 nenad,
Novi najveći optički teleskop... :) World's Largest Mirror Opticians at Steward Observatory are now casting the world's largest one-piece mirror blank, a giant monolith 8.4 meters (27.5 feet) across. It's all happening inside a giant oven that rotates about seven times per minute, inside which the molten glass forms a curved shape close to the desired final surface. Once the casting is complete, the oven will continue to spin as the 20-ton blank cools over the next few weeks. A second blank will be cast later, and when finished the two mirrors will form the heart of the Large Binocular Telescope
zvezde.62 nenad,
Detaljnije o "susretima" letelice Galileo sa Evropom ICE VOLCANOES RESHAPE EUROPA'S CHAOTIC SURFACE Ice-spewing volcanoes and the grinding and tearing of tectonic plates have reshaped the chaotic surface of Jupiter's frozen moon Europa, images from NASA's Galileo spacecraft reveal. The images, captured when Galileo flew within just 692 kilometers (430 miles) of Europa on Dec. 19, were released at a news briefing today at NASA Headquarters, Washington, DC. Although the images do not show currently active ice volcanoes or geysers, they do reveal flows of material on the surface that probably originated from them, said Galileo imaging team member Dr. Ronald Greeley of Arizona State University, Tempe, AZ. "This is the first time we've seen actual ice flows on any of the moons of Jupiter," said Greeley. "These flows, as well as dark scarring on some of Europa's cracks and ridges, appear to be remnants of ice volcanoes or geysers." The new images appear to enhance Europa's prospects as one of the places in the solar system that could have hosted the development of life, said Greeley. "There are three main criteria to consider when you are looking for the possibility of life outside the Earth -- the presence of water, organic compounds and adequate heat," said Greeley. "Europa obviously has substantial water ice, and organic compounds are known to be prevalent in the solar system. The big question mark has been how much heat is generated in the interior. "These new images demonstrate that there was enough heat to drive the flows on the surface. Europa thus has a high potential to meet the criteria for exobiology," Greeley added. "This doesn't prove that there is an ocean down there under the surface of Europa, but it does demonstrate that it is a scientifically exciting place," said Galileo imaging team member Dr. Robert Sullivan, also of Arizona State University. The images also reveal a remarkable diversity in the geological age of various regions of Europa's surface. Some areas appear relatively young, with smooth, crater-free terrain, while others contain large craters and numerous pits, suggesting that they are much older. The icy crust bears the signs of having been disrupted by the motion of tectonic plates. "There appear to be signs of different styles of tectonism," said Greeley. "In many areas we see that the crust was pulled apart in a spreading similar to the processes on the sea floor on Earth. This is different from the tectonic processes at work on, say, Jupiter's moon Ganymede. This suggests that Europa's interior may be different from Ganymede's." Galileo scientists will have a better chance to understand Europa's interior when the spacecraft gathers gravity data on another flyby next November. The gravity field is measured by tracking how the frequency of Galileo's radio signal changes as it flies past the moon. This was not possible during the recent flyby because radio conditions were degraded as Jupiter passed behind the Sun from Earth's point of view. Europa is crisscrossed by an amazingly complex network of ridges, said Sullivan. "Ridges are visible at all resolutions," he explained. "Closely paired ridges are most common. With higher resolution, ridges seen previously as singular features are revealed to be double." Some of the ridges may have formed by tension in the icy crust: as two plates pull apart slightly, warmer material from below might push up and freeze to form a ridge. Other ridges may have been formed by compression: as two plates push together, the material where they meet might crumple to form the ridge. In addition to ice flows and tectonics, Greeley and Sullivan noted that some areas on Europa seem to have been modified by unknown processes that scientists are still debating. Greeley said that some areas, for example, seem to have been modified by "sublimation erosion" -- the evaporation of water and other volatiles such as ammonia and methane into the vacuum of space. "Something is destroying the topography," said Greeley, "and this sublimation erosion is a good candidate for what is at work." During last month's encounter, Galileo flew more than 200 times closer to Europa than the Voyager 2 spacecraft did in 1979. After a swing past Jupiter next week in what mission engineers call a "phasing orbit," Galileo's next targeted flyby will take it again past Europa as it passes within 587 kilometers (364 miles) on February 20.
zvezde.63 nenad,
Idemo na Saturn... :) CASSINI PROGRAM STATUS Having successfully completed recent space environmental tests, NASA's Cassini spacecraft, destined for the planet Saturn, has been returned to JPL's spacecraft assembly facility for a final round of systems testing. The program remains on schedule and within budget. The spacecraft, due for launch Oct. 6, will be shipped this spring to NASA's Kennedy Space Center in Florida for pre-launch preparations. Cassini last week completed a month of so-called "shake and bake" tests that imitate the vibration forces and extreme temperatures the spacecraft will have to withstand during its upcoming launch and flight through space. Reflective gold- colored space blankets have been sewn and laced into place on the Saturn orbiter. The 24-layer blankets will protect Cassini's computers and other systems from the extreme hot and cold of space. The painstaking assembly of Cassini, the most sophisticated U.S. planetary spacecraft ever built, has been under way at JPL since 1995. Development of the mission began in 1989 and has involved the efforts of thousands of people at university and government research labs and technology and business firms across the country. In Europe, work continues on the Huygens probe that will be mounted on Cassini and dropped via parachute to the surface of Saturn's largest and most mysterious moon, Titan. The Huygens probe will be mated with the Cassini spacecraft at Kennedy Space Center in late spring. After a nearly seven-year trip, Cassini will reach Saturn in July 2004. There, it will enter orbit around the ringed planet and make detailed, four-year observations of Saturn, its largest moon Titan, several smaller icy moons, and the magnetic environment surrounding the planet. The Huygens probe destined for Titan's surface is provided by the European Space Agency (ESA). The probe will parachute to the surface of Titan, thought to resemble an early Earthlike environment before life began. The mission is an international effort of NASA, ESA and the Italian Space Agency (ASI), and is managed for NASA by JPL.
zvezde.64 nenad,
Hubble Servicing Mission Under Way Early on February 14th a pair of space-walking astronauts aboard the shuttle Discovery successfully installed two new instruments on the Hubble Space Telescope. The one dubbed NICMOS (Near-Infrared Camera and Multi-Object Spectrometer) will explore the universe at infrared wavelengths longer than 1 micron. The other package, called STIS (Space Telescope Imaging Spectrograph) can obtain the spectra of many objects simultaneously. Project scientists say the instruments have passed a "liveness" test but that it will be several weeks before all their systems can be checked out. STIS, for example, operates with a high-voltage power supply that can't be turned on until air inside the instrument has been completely evacuated. Look for the first press conference to show off new results in early May
zvezde.65 nenad,
Novi rezultati pokazuju da su Plejade bliže nego što se mislilo, ali i da je svemir za oko 10% veći. Early Results from Hipparcos Today European astronomers announced a series of results from the Hipparcos mission, though the full data set will not be made public until June. Launched in August 1989, the spacecraft spent several years measuring the positions and brightnesses of stars down to magnitude 11 with unprecedented accuracy. Among the new findings is that the Pleiades star cluster appears to be about 10 percent nearer than previously thought. Hipparcos data pegs the distance at 360 light-years. Also Cepheid variables, the pulsating stars that astronomers use to gauge the distances to other galaxies, are intrinsically more luminous -- and thus farther away -- than believed. This implies that the universe may be larger than previous estimates by about 10 percent, and also that the most distant (and thus oldest) stars are no more than about 11 billion years old. Cosmologists should find that good news, since they now estimate that the universe as a whole is some 12 billion years old.
zvezde.66 vstan,
Dok ne stignu novi snimci sa Evrope evo tri stara snimka. evropa.zip
zvezde.67 morkin, -> #60, nenad
> Europa's Eruptions > strange tectonic collapse in others. More and more evidence > suggests that Europa's outer crust is thin, perhaps only a few > kilometers thick in places, and that something else -- an ocean > or rock-ice-water slush -- lies just out of sight below. Još samo da sačekamo da na Mesecu otkriju "crni objekat" čije su dimenzije u odnosu 1:4:9...
zvezde.68 space.ace, -> #67, morkin
>> Još samo da sačekamo da na Mesecu otkriju "crni objekat" čije su dimenzije >> u odnosu 1:4:9... Za to ćeš morati da sačekaš do 2001...
zvezde.69 nenad,
Does 51 Peg's Planet Really Exist? According to David Gray, an astronomer at the University of Western Ontario, the planet-size companion to the star 51 Pegasi does not exist. This is the star that started the current rush of extrasolar planet discoveries back in 1995. Astronomers Michel Mayor and Didier Queloz then claimed that subtle shifts in the star's spectrum show that it is nodding back and forth relative to Earth, the effect of an object with at least half Jupiter's mass circling nearby every 4.2 days. But Gray, who is an expert on stellar spectroscopy, believes that the star itself is causing the effect. He found that the shape of an absorption line was tilting one way, then the other, in lock step with the putative planet's orbit. Orbital motions can't change the shape of a spectral line, only its position. "Therefore," Gray wrote in Nature for February 27th, "the planet hypothesis is no longer an adequate interpretation of the data." Instead, says Gray, 51 Pegasi seems to undergo complex pulsations that somehow tilt the lines back and forth. However, planet-hunters are rising to 51 Peg's defense, arguing that the pulsations Gray envisions can't become strong enough to reproduce the observed behavior. The outcome of this debate will affect the viability of planets presumed to circle three other stars too.
zvezde.70 nenad,
Pioneer 10's Silver Anniversary March 2nd marks the 25th anniversary of the launch of Pioneer 10. A product of NASA's Ames Research Center, it might be called the "Energizer Bunny" of interplanetary spacecraft. It's now almost exactly 10 billion kilometers from Earth, more than 9 light-hours away. Pioneer 10 made history with its close flyby of Jupiter in December 1973. Along with Pioneer 11, which arrived the following year, this 570-pound spacecraft took many pictures of Jupiter and its major moons. But the twin spacecraft will be most remembered for their measurements of the fields and charged particles in Jupiter's immense magnetosphere. The 260-kilogram spacecraft was equipped with 11 instruments, only one of which continues to operate.
zvezde.71 nenad,
COOL, SAFE, COMPACT, LIGHT, EFFICIENT, NON-POLLUTING New JPL-USC Methanol Fuel Cell Shows Promise For Zero-Emission Vehicles A revolutionary design for a cool-process, zero-emission methanol fuel cell just patented by Caltech's Jet Propulsion Laboratory and the University of Southern California is already under fast-track development for a wide range of uses. In one major project, developers believe they can create a unit about the size of a thick paperback book that can run continuously for weeks at a time, producing 50 watts of power, consuming about a pint of methanol fuel per day, and emitting only water and carbon dioxide. The technology, whose development was funded by the U.S. Defense Advanced Research Projects Agency (DARPA) and private sources, is easily scaleable into larger units capable of powering portable non-polluting electronic equipment or, eventually, zero-emission motor scooters or cars. The U.S. military is interested in the technology for its potential of providing portable power to soldiers in the field. A private sector corporation, DTI Energy, Inc., headquartered in Los Angeles, has licensed the technology and intends to develop and sublicense various prototypes and applications. It has initially designed units of up to 5 kilowatt output, powerful enough to run a light-duty vehicle. "This fuel cell may well become the power source of choice for energy-efficient, non-polluting electric vehicles," said JPL fuel cell team manager Gerald Halpert. "This invention also has vast potential to improve the environment by providing clean energy in portable form," noted Nobel prize-winning chemist George Olah of USC, one of the co- inventors. Like all fuel cells, the JPL/USC device, called a "Direct Methanol, Liquid Feed Fuel Cell," converts the chemical energy of its fuel directly into electrical current without burning the fuel. It has many remarkable advantages: - It uses the common and widely used substance, methanol (a liquid also known as methyl alcohol) as the base fuel mixed with water. Methanol is inexpensive (currently, approximately 40 cents per gallon), easily manufactured from coal or natural gas, and safe to store--existing gas stations could easily sell it. - It runs relatively cool--below the boiling point of water- -and is compact. Existing fuel cells typically operate at high temperatures, some at temperatures hot enough to melt many metals, thus requiring bulky thermal insulation and structural reinforcement to mitigate safety hazards. - It creates no toxic byproducts whatsoever. The methanol fuel is completely converted to carbon dioxide (CO2 ) and water. - It is simple and relatively inexpensive to manufacture, consisting of little more than a membrane coated with platinum or other noble metals. The cell itself has no moving parts. Its precious metals are used in small amounts and can be completely recovered and recycled at the end of the device's life. - It is efficient. In its existing configuration, it converts more than 34 percent of the theoretical energy content of the fuel into usable power. This is twice the efficiency of existing gasoline engines. Developers believe that improvements now on the drawing board will push the efficiency to more than 45 percent of theoretical energy content. A U.S. patent for an "aqueous liquid-feed organic fuel cell using solid polymer electrolytic membrane" was issued early this month with Caltech, JPL's parent organization, and USC as joint patent holders. "In addition to not polluting the environment," noted JPL's Dr. Subbarao Surampudi, who supervises JPL's Electrochemical Technologies Group, "we believe that cells of this design can replace batteries in many applications and provide reliable emergency power in disasters." Battery manufacturing involves toxic materials, so the disposal of used batteries has become a major problem, scientists note. Prototype cells have been assembled and tested at JPL. According to Dr. Halpert, these models have run for more than 200 hours continuously at JPL and for more than 3000 hours intermittently--equivalent to approximately 150,000 miles--at partner Giner Inc.'s labs without loss of performance. Current design goals envision units that can operate continuously for 1000 or more hours, and, eventually, units that can produce the 40 kilowatts or more required to power a full-sized car. "The system's simplicity as a clean-energy alternative to the use of fossil fuel-powered combustion engines will generate widespread appeal in the automotive industry," predicts Halpert. The fuel cell's design is quite simple. A membrane divides the cell in half, with methanol fuel in water on one side and gas, either oxygen or air, on the other. The membrane is coated on both sides with a special, electrochemically active catalytic coating developed by JPL. The liquid side is the anode. Methanol--a molecule consisting a single carbon atom linked to three hydrogen atoms and one oxygen-hydrogen (hydroxyl) group-- spontaneously reacts at the catalytic surface. In this reaction, the carbon-hydrogen bonds are broken. The hydrogen atoms lose their electrons and become protons, also known as hydrogen ions, and migrate across the membrane to the gas side, the cathode. There, on the cathode's catalytic surface, they combine with oxygen from the air to produce water. The electrons given up on the anode side generate the current. The carbon left on the liquid side is completely converted into non-toxic carbon dioxide. The cell is fuel-versatile, operating on methanol-derived fuels. "A major problem with the existing device, however, is that the membrane used allows not just protons to cross to the cathode side, but also methanol, thus degrading performance," according to Sekharipuram R. Narayanan, who spearheaded the catalyst development work. The Loker Institute's Drs. Prakash, Olah, Qungie Wang and Marshall Smart, along with JPL's Drs. Narayanan, Surumpudi and Halpert, have pioneered the development of improved proton membranes that will permit the construction of a new generation of cells achieving greater efficiency by blocking methanol migration. USC and JPL have applied for patents on these new membranes. The research team also hopes to drastically cut the cost of the proton exchange membrane, which is currently very expensive, the major economic roadblock to widespread applications. Prakash, a professor in the department of chemistry in the University of Southern California's College of Letters, Arts and Sciences and at the Donald P. and Katherine T. Loker Hydrocarbon Institute, has collaborated with Dr. Olah, the Institute's director, for decades. Olah was awarded the Nobel Prize in chemistry in 1994 for his work with superacids, similar to substances used in the creation of the methanol fuel cell membrane. Olah has long maintained that chemistry can provide solutions to environmental problems while maintaining economic growth without destructive effects. "Both George and I think that this fuel cell is a prime example of this belief," said Prakash. It was Prakash who in 1989 approached Surampudi of JPL seeking expertise in electrochemistry to design the cell and electrocatalysts to make the system work. Anthony Laconti, John Kosek and Cecilia Cropley of Giner Corp. were also involved in the development of the cell. "We think this new technology will bring the fuel cell down to earth for good," Prakash added. JPL/USC, together with Giner Corp., is working on a contract from the Department of Defense to develop a 50-watt methanol fuel cell to replace lithium batteries used in various Department of Defense applications; a 150-Watt development program will begin in April, 1997. Other government entities involved include the Army Research Office and the Army Research and development command. Harvey Frank, one of the co-inventors, has been working on fuel cells since 1960. Starting in 1989, the methanol fuel cell work was conducted by chemists Olah and Surya Prakash of USC and developed in cooperation with JPL researchers Halpert, Surampudi, Narayanan and Eugene Vamos, as well as the support of JPL team members Thomas Valdez, Andrew Kindler, Elizabeth Yen, William Chun, Barbara Nakamura and Albany Lee. Licensee DTI Energy Inc. intends to develop a hybrid system for vehicular applications, according to President Todd Marsh. The fuel cells will be used to recharge continuously both conventional batteries and more advanced batteries, extending the range of the vehicles they power. "As we develop expertise in this area," he explained, "we will concurrently be developing a full range of applications, including stand-alone power, power generators, uninterrupted power supplies, and consumer electronic battery replacement, among others." JPL's Technology Affiliates Program, which made the technology available for license to DTI Energy Inc., is designed to help U.S. companies improve their competitive positions in the global economy by transferring JPL technology into the marketplace. U.S. industry may tap the commercial potential of JPL's technology development activities via mechanisms ranging from reports, seminars, patent and software licenses to direct interaction with laboratory technologists. The nine-year-old JPL program now includes nearly 120 companies and has facilitated more than 200 technology transfer projects to benefit companies and the public.
zvezde.72 morkin, -> #70, nenad
> "Energizer Bunny" of interplanetary spacecraft. It's now almost > exactly 10 billion kilometers from Earth, more than 9 light-hours > away. Pioneer 10 made history with its close flyby of Jupiter in A gde je sada? Jel još između Neptuna i Plutona? Koliko ima do Plutona?
zvezde.75 zormi, -> #72, morkin
*> "Energizer Bunny" of interplanetary spacecraft. It's now almost *> exactly 10 billion kilometers from Earth, more than 9 light-hours *> away. Pioneer 10 made history with its close flyby of Jupiter in * * A gde je sada? Jel još između Neptuna i Plutona? Koliko ima do Plutona? Trenutno je otprilike dvostruko dalje od nas nego Pluton (koji nam je inače do 1999 god malo bliži od Neptuna jer mu orbita preseca Neptunovu). Pluton je inače udaljen 30-50 AU (astronomskih jedinica = razdaljina Zemlja-Sunce = oko 150 mil.km) dakle ima jako ekscentričnu putanju, ali je sonda daleko iza i njegovog krajnjeg dometa.
zvezde.76 nenad, -> #72, morkin
> A gde je sada? Jel još između Neptuna i Plutona? Koliko ima do Plutona? Meni se čini da je pre neku godinu izašao iz okvira orbite Plutona i napustio sunčev sistem.
zvezde.77 morkin, -> #75, zormi
> inače do 1999 god malo bliži od Neptuna jer mu orbita preseca > Neptunovu). Po toj logici, jednog dana će se sudariti. Zna li se kada (za koliko miliona godina)? > ali je sonda daleko iza i njegovog krajnjeg dometa. Da li šalje neke signale? Pisalo je da radi samo jedan uređaj. Koji? Ja baš zaređao sa pitanjima...
zvezde.78 zormi, -> #77, morkin
*> inače do 1999 god malo bliži od Neptuna jer mu orbita preseca *> Neptunovu). * * Po toj logici, jednog dana će se sudariti. Zna li se kada (za koliko * miliona godina)? Teško. Svemir je suviše veliki, orbita Plutona je vrlo nagnuta i ne kači direktno Neptunovu, Pluton obidje Sunce za nekih 250 godina a Neptun za (zaboravio sam tačno) stotinak pa da se baš susretnu i pogode... *> ali je sonda daleko iza i njegovog krajnjeg dometa. * * Da li šalje neke signale? Šalje još signal ali je isti bar 50 dB ISPOD nivoa kosmičkog šuma tako da se teško izvlači i mala je propusna moć. Uglavnom se radi o merenjima solarnog "vetra" i magnetnog polja. Pored toga što je sonda sve dalje od nas pa signal slabi, sve je dalje i od Sunca koje napaja njene baterije (ne znam koji će uredjaj ostati poslednji da troši rezerve, mogu da potražim). Sa te daljine Sunce je naj- sjajnija zvezda na nebu - ali ništa više od toga. Uskoro će potpuno isključena sonda ohladjena na svega par stepeni iznad apsolutne nule nastaviti put ka zvezdama i za 30000 godina proći pored jedne slabašne zvezdice. Jedina funkcija koja joj preostaje je funkcija glasnika, odnosno činjenica da postoji, da je napravljena na Zemlji i da je stigla toliko daleko. Na sebi ima i ploču sa ugraviranim raznim simbolima o Zemlji i čoveku za slučaj da je neko presretne (posle najnovije serije SF filmova možda je bilo bolje detonirati neku ugradjenu bombu dok je još u dometu ;)
zvezde.79 nenad,
Hale-Bopp Spins Its Magic Recent observations by European astronomers using the 1-meter telescope at Pic du Midi Observatory in France show that Comet Hale-Bopp (C/1995 O1) rotates every 11.47 hours, but that the spin rate actually varies by about a half hour over a three-week period. This complex rotation, which may include precession, is combining with a prominent jet or jets of dust to create the multiple bright shells that have been observed on the sunward side of the nucleus. The comet will be closest to the Earth on March 22nd (197 million kilometers) and to the Sun on April 1st (137 million km).
zvezde.80 nenad,
Nova letelica namenjena kruženju oko Meseca je spremna, biće lansirana u septembru. Uz poruku je njen crtež. Lunar Prospector Rollout On March 12th project officials showed off the completed Lunar Prospector spacecraft at Lockheed-Martin in Sunnyvale, California. Costing a total of $63 million, the mission is set for launch on September 24th. Lunar Prospector will circle the Moon for a year, studying magnetic fields, gravity, and surface characteristics. One key experiment will look for telltale neutrons emitted by water ice thought to lie in the permanently shadowed lunar poles. lp01.jpg
zvezde.81 nenad,
Noćas je Mars u opoziciji, ovih dana je najbolje vreme ako želite da ga gledate. Uz poruku je jedna skorašnja slika marsa sa Hablovog svemirskog teleskopa. Mars at its Best The red planet reaches opposition on March 17th, when it rises around sunset and shines all night. Although ever so slightly dimmer than Sirius at magnitude -1.3, Mars will attract more attention -- partly because it stares steadily at us with little or no twinkling and shines with a distinctive, orange-gold light. It will gain special notice above the almost totally eclipsed Moon on the night of March 23rd. The Martian disk appears 14 arcseconds across, tipped slightly so that its north pole is in view. marshst.gif
zvezde.82 nenad,
A 20. marta u 5 minuta do 3 popodne počinje proleće. :) March Equinox Spring returns to the Northern Hemisphere, and autumn to the Southern, at 13:56 Universal Time on March 20th. At that moment the Sun crosses the celestial equator as it moves northward among the stars.
zvezde.83 pdeze,
Pozdrav! Gde se moze videti Hale Bopp ovih dana? P.S. Nisam bas u toku otkad sam potrosio vreme na internetu :(
zvezde.84 zormi, -> #83, pdeze
* Gde se moze videti Hale Bopp ovih dana? Posle zalaska Sunca (oko 19h) ka zapad-severozapadu negde 20-tak stepeni iznad horizonta, nećeš promašiti...
zvezde.85 stameni, -> #84, zormi
>> * Gde se moze videti Hale Bopp ovih dana? >> >> Posle zalaska Sunca (oko 19h) ka zapad-severozapadu negde 20-tak >> stepeni iznad horizonta, nećeš promašiti... Zna li ko u kom je sazvežđu? Ja mislim Zmijonoša, ali nisam siguran...
zvezde.86 nenad, -> #83, pdeze
> Gde se moze videti Hale Bopp ovih dana? The Great Comet of 1997 is now entering "prime time." The twin-tailed spectacle is obvious in both the morning and evening skies from midnorthern latitudes. Comet Hale-Bopp sports a long, thin, faint gas tail and a shorter, broader, brighter dust tail. The interplanetary interloper comes closest to Earth on March 22nd, though it will be on the far side of the Sun and 197 million kilometers away at the time. Over the following two days the comet sails just 5 degrees north of M31, the Andromeda Galaxy. The comet's total visual magnitude is now about -0.5. To see Comet Hale-Bopp at its best you should look at least 1╝ hours before sunrise or after sunset, though its starlike inner coma can still be seen in twilight. It's about 20░ above the northeastern horizon before dawn, and roughly the same height above the northwestern horizon in the evening.
zvezde.87 nenad,
> Zna li ko u kom je sazvežđu? Ja mislim Zmijonoša, ali nisam > siguran... Na ovoj slici se vidi po danima gde će se nalaziti i moći videti u večernjim časovima. marpm2.jpg
zvezde.88 nenad,
> Zna li ko u kom je sazvežđu? Ja mislim Zmijonoša, ali nisam > siguran... ...a na ovoj gde se može videti u jutarnjim časovima, takođe po danima. maram2.jpg
zvezde.89 nenad,
A za one zainteresovane šta učene glave misle i rade po tom pitanju (Hale-Bopp kometa), evo i te informacije. :) ULYSSES SCIENTISTS BEGIN CAPTURING UNIQUE VIEW OF HALE-BOPP Scientists on a joint NASA-European Space Agency mission to study the poles of the Sun are using the Ulysses spacecraft's unique, high latitude orbit to help understand changes in comet Hale-Bopp as it nears the lower latitudes of the Sun while spewing its outer layers of gas and dust. Using solar wind data from the spacecraft, a team of interdisciplinary scientists at NASA's Jet Propulsion Laboratory, the University of Colorado at Boulder and an international group of amateur astronomers known as the "Ulysses Comet Watch" have been observing other comets in the same way as they return from the far reaches of space. This unique, collaborative research effort focuses specifically on what happens to comets as they are exposed to different solar wind conditions at various solar latitudes. "Until recently, no spacecraft had flown through high latitudes above the Sun's equator and the properties of the solar wind at these latitudes could only be surmised," said Dr. Edward Smith, project scientist of the Ulysses mission at JPL. "In the last two years, Ulysses has studied the steady, high-speed winds at high latitudes, and alternating, slow and fast winds near the Sun's equator. Hale-Bopp is about to enter the lower latitude zone, where the disturbed solar wind resides, and where dramatic changes in the comet's plasma tail are expected to occur." The Ulysses Comet Watch group, spearheaded by Drs. John C. Brandt and Martin Snow of the University of Colorado's Laboratory for Atmospheric and Space Physics, and Carolyn Collins Petersen, now of Sky Publishing Corp. in Cambridge, MA, will provide worldwide observations of the returning comet as it descends from the polar regions of the Sun. Images from more than 200 observers around the world will be posted on the Ulysses Comet Watch home page on the Internet at http://lasp.colorado.edu/ucw/. Observations will continue to be posted well after the comet makes its closest approach to the Sun on April 1. The Ulysses group is not watching for changes in the comet's more visible, wider and yellowish dust tail, though, but rather for changes in its narrower, paler, often bluish plasma tail, which consists of ionized gas being emitted by the comet and picked up by the magnetic field being swept along by the solar wind. "We are particularly interested in the comet's plasma tail, which 'turned on,' or began to outgas, when Hale-Bopp was about 1.5 astronomical units (140 million miles) from the Sun, the equivalent of 1.5 times the distance between the Earth and the Sun," Brandt said. Cometary plasma tails change constantly due to their interactions with slow and high-speed solar wind. One of the more dramatic changes that can occur is the abrupt disconnection of the tail, which then drifts away. Often a new tail will form within hours. "Comets lose their plasma tails when they are subjected to abrupt reversals in the direction of the solar wind magnetic field," Smith said. "This magnetic field reversal typically happens in the equatorial regions twice per solar rotation, or about every 13 days. They don't occur at high latitudes." Consequently, Brandt and his team expect to see such dramatic changes in the comet's plasma tail only in the equatorial regions of the solar wind -- between 20 degrees north and 20 degrees south of the Sun's equator. Modeled after the very successful international Halley Watch observation networks, which operated during 1985 and 1986, the Ulysses Comet Watch network has been operating since late 1992. Observers have studied a number of comets, and have supplied sequences of high-quality images of comets de Vico, which returned in September 1995, and Hyakutake, which was discovered and observed last year. Scientists first discovered that the plasma tails of these comets change and drop off according to their latitudes with respect to the Sun during these two comet returns. Observers are now beginning to submit early images of Hale-Bopp, which, according to Brandt, are looking equally as promising. "In fact, we expect the network's output of Hale-Bopp images to be fantastic," he said. "At equatorial latitudes, the solar wind moves at an average speed of about 450 kilometers per second (970,000 miles per hour) with large variations in speed and density," Brandt continued. "This type of wind apparently comes from the equatorial streamers so clear at solar eclipses. The plasma tail of a comet experiencing this part of the solar wind has a distinctly disturbed appearance which varies over time, and undergoes disconnection events as it experiences reversals of the magnetic field. "By contrast, when the same comet travels through the polar latitudes, it encounters a more steady, less dense and faster solar wind, moving at about 750 kilometers per second or 1.6 million miles per hour," Brandt said. "There are smaller variations in speed and density and no magnetic field reversals. Consequently, the plasma tail looks much less turbulent and does not have disconnection events. So, the comet, by acting as a 'solar wind sock,' can be used to map the conditions in different latitudes of the solar wind." Comet Hale-Bopp is ideally suited to show these types of tail changes because of its high-latitude orbit. Ulysses' measurements of the solar wind from the same latitude, combined with ground-based observations of comet tails, will help scientists better understand the physics involved in cometary gases and their interaction with the outward-flowing solar wind. From this information, they may be able to understand the solar wind in regions that have never been accessible to spacecraft before, such as very close to the Sun or at much higher latitudes above and below the Sun's equator.
zvezde.90 nenad,
Sutra uveče, odnosno iz Evrope prekosutra ujutru biće moguće videti pomračenje Meseca. A Deep Partial Lunar Eclipse Skywatchers almost everywhere in the Americas will have a fine view of the Moon being eclipsed on the night of March 23rd, if the weather is clear. Viewed from Europe and Africa, the Moon will be in the western sky before or during dawn on the morning of the 24th. Adding to the scene will be the bright orange planet Mars about 12° above or to the upper right of the Moon. Here are Eastern Standard Times of the major events: Partial eclipse begins at 9:58 p.m.; mid-eclipse is at 11:39 p.m.; partial eclipse ends at 1:21 a.m. March 24th (convert these to your local time zone).
zvezde.91 nenad,
Naučnici još uvek ispituju fosilne ostatke pronađenje na meteoritu koji potiče sa Marsa, ali po svemu sudeći to njihovo istraživanje neće dovesti ni do kakvih konačnih zaključaka. Life on Mars Revisited Planetary scientists gathered in Houston, Texas, this week to debate the likelihood that life existed on Mars billions of years ago. The focus of their attention was a Martian meteorite designated ALH 84001. Last August, scientists from NASA and Stanford University built a case for microscopic fossils within the 4-pound stone, and at the Houston meeting more that 30 papers detailed new studies of the rock. The life hypothesis hinges in part on the origin of bits of carbonate minerals within which the putative fossils were found. Several presenters maintained that the carbonates formed slowly at temperatures below the boiling point of water. But others argued that the minerals came together while at several hundred degrees -- much too hot to sustain any known organisms. Meanwhile, several research teams have searched for chemical fingerprints of life, and whether ultramicroscopic structures are fossilized microbes or just flecks of mineral. As NASA scientist Doug Blanchard summed up, "It's still too early to conclude about life on Mars -- no one knows the truth just yet." NASA and the National Science Foundation plan to distribute more samples of the unique meteorite next month, to begin a new round of tests by scores of scientific teams worldwide.
zvezde.92 nenad,
A Binary's Dust Disk Using a coronagraphic camera on Mauna Kea, astronomers have found what may be a gigantic disk of dust, some 2 trillion kilometers in diameter, surrounding BD +31°643, an 8th-magnitude binary star 1,100 light-years distant in the constellation Perseus. Dust disks or shells have been indirectly discerned around dozens of stars via infrared spectral measurements. But, until now, astronomers had only managed to "photograph" such a feature around one main-sequence star, Beta Pictoris. In Nature for March 6th, Paul Kalas (Max-Planck Institute for Astronomy) and David Jewitt (University of Hawaii) surmise that the newfound disk would require a Jupiter's worth of planetesimals, which create dust by smashing into one another, to sustain itself. If each of these putative colliders were a typical large rocky asteroid, 100 km across, at least a billion such objects must swarm around the binary's two B-type stars. Kalas's upcoming Hubble Space Telescope observations will inspect the enigmatic disk with 10 times better resolution than the discovery image.
zvezde.93 guta,
U čast Hale-Bopp komete, prenosim nekoliko sličica sa NASA site-a. Uz ovu poruku je slika zamišljenog udara komete u Zemlju - u pitanju je umetnički prikaz, i fenomenalno izgleda. comet.jpg
zvezde.94 guta,
Još jedan prikaz udara komete u Zemlju, NASA site. earth.gif
zvezde.95 guta,
U arhivi uz poruku se nalazi 11 slika Hale-Bopp komete, u raznim stadijumima približavanja Zemlji, pored koje sada prolazi. Lepo se može videti formiranje repova kako se kometa približava Suncu. halebopp.zip
zvezde.96 vlajel, -> #95, guta
*> *> U arhivi uz poruku se nalazi 11 slika Hale-Bopp komete, u *> raznim stadijumima približavanja Zemlji, pored koje sada *> prolazi. Lepo se Ima li podataka kada će se najbolje videti sa ovih naših prostora ?
zvezde.97 nenad,
Večeras se kometa videla i iz Beograda golim okom. Uz poruku je slika sa šemom gde treba tražiti kometu u prvoj polovini aprila, ali prema onome što sam video lakše je uočiti nju nego zvezde i sazvežđa na osnovu kojih je treba pronaći... aprpm1.jpg
zvezde.98 nenad,
Uz poruku je crtež gde treba tražiti kometu krajem aprila i početkom maja... Hale-Bopp Weakened By the Moon The glory of Comet Hale-Bopp suffers slightly due to a sky significantly brightened by the Moon, which will be full on the night of April 22nd. Reports indicate that the comet is still near magnitude -0.5 with a dust tail visible to the unaided eye and an ion tail visible in binoculars. Even in strong moonlight, the comet will be unmistakable. Look at least 1Ż hours after sunset when the sky is completely dark. Comet Hale-Bopp should be obvious about 20° to 30° above the west-northwestern horizon (depending on your latitude). aprpm2.jpg
zvezde.99 nenad,
Zakonetka stara 30 godina je možda pred rešenjem - šta je uzrok iznenadnim emisijama gama zraka u kosmosu? Skorašnja posmatranja su ponudila neka moguća rešenja... Gamma-Ray Bursters: Far or Near? Astronomers may have come one step closer to solving a 30-year-old puzzle -- the nature and origin of gamma-ray bursts. On February 28th a gamma-ray detector aboard the Italian-Dutch spacecraft BeppoSAX was triggered, and the satellite's X-ray cameras saw a simultaneous flash in the constellation Orion. That alone was reason for interest. But the news that followed has sent observatories worldwide into a flurry of activity. In a March 12th IAU Circular, Paul J. Groot (University of Amsterdam) and his colleagues announced that they pointed the 4.2-meter William Herschel Telescope on La Palma to the location of the X-ray hot spot and found an exceedingly faint light source that then faded from view between March 1st and 8th. Images from other observatories confirm the existence of what appears to be a distant galaxy. This encourages scientists who think gamma-ray bursts originate billions of light-years away. However, another IAU Circular on April 17th reintroduced the uncertainty. Patricia Caraveo (Institute of Cosmic Physics, Milan) and her colleagues report that a pointlike object seen by the Hubble Space Telescope in the same spot is moving across the sky at a rate of a half arcsecond per year. This could mean that the bursting gamma-ray source may be a relatively nearby object within our own Milky Way. Establishing the distances to gamma-ray bursters is crucial since that determines how much energy they actually give off.
zvezde.100 nenad,
Da li se ceo svemir okreće oko svoje ose? Možda će neki osnovni zakoni morati opet da se menjaju, možda se svetlost ne kreće svuda istom brzinom... A New Spin on the Universe Does the universe have something akin to a rotational axis? Two astronomers suggest it might. They made the surprising finding by studying radio observations of distant galaxies. In Monday's issue of Physical Review Letters, John Ralston (University of Kansas) and Borge Nodland (University of Rochester) report on how radio signals in the cosmos seem to be polarized preferentially in certain directions, suggesting that there is a universal axis. If confirmed, this could have significant consequences for our understanding of the universe. Ralston and Nodland explain that the laws of electromagnetism may need revising, that the universe didn't expand as uniformly as now thought, or that light in intergalactic space may travel at different speeds for some reason.
zvezde.101 nenad,
Šema za gledanje Hale-Bopp komete u prvoj polovini maja. maypm1.jpg
zvezde.102 nenad,
Nova planeta je otkrivena, istina ne u našem sistemu ali na svega 50-ak svetlosnih godina daleko. Kruži oko Ro zvezde u sazvežđu Severna Kruna i verovatno je veličine Jupitera. Astronomi kažeu da o životu na njoj nema ni govora. Prema tome sledeće izbore definitivno treba dobiti. ;) A New Extrasolar Planet A team of eight astronomers has found evidence for a planet around Rho Coronae Borealis, a 5th-magntiude star about 50 light-years away. Spectroscopic measurements made over 11 months show that the star's velocity toward and away from Earth varies by +/- 67 meters per second over a 40-day period. These values argue for a companion at least as massive as Jupiter in an orbit only about 40 million km in radius -- 1/4 of the Earth-Sun distance. Since Rho Cor Bor is a star much like our Sun, the suspected planet would have a temperature of about 300° Celsius (more than 500° F) -- making it an unlikely habitat for life. The companion's orbit is roughly circular, implying it formed at roughly that location from gas and dust in the coalescing nebula that created the star. The observing team was led by Robert Noyes of the Harvard-Smithsonian Center for Astrophysics.
zvezde.103 nenad,
Po svemu sudeći ipak je dokazano postojanje malih (veličine kuće ;) ledenih kometa koje konstantno padaju na Zemlju praveći rupe u jonosferi. Ako se dokaz potvrdi i ako se ispostavi da su one u tom istom ritmu padale na Zemlju od njenog postanka, to bi značilo da večina vode na Zemlji potiče sa njih, a isto bi važilo i za većinu organskih materija. Return of the Minicomets Spectacular images from an orbiting satellite show that the Earth is being pelted more or less continuously by small comet-like objects. The new views were released on May 28th by Louis A. Frank (University of Iowa), whose camera on the Polar spacecraft recorded the intruders as they sliced through the upper atmosphere. Frank first called attention to these minicomets in 1986, based on their appearance in other spacecraft data. But his idea was widely criticized because there was no other observational evidence for the comets' existence (for example, Apollo seismographs did not record them striking the Moon, nor does the tenuous lunar atmosphere contain water). However, the new Polar images have convinced many former skeptics. Frank believes the interlopers have a mass of 20 to 40 tons and consist of almost pure ice. They begin to break up at altitudes at least 10,000 kilometers above Earth, and their water creates neutralized "holes" in the ionosphere that are seen by Polar's cameras. The comets strike at rates of five to 30 per minute. If this rate has been steady over billions of years, they have contributed much of Earth's water and perhaps a large proportion of its organic constituents. For additional information and images, see Louis Frank's Web site at the University of Iowa's Physics Department.
zvezde.104 burazer,
Ovo poruku nisam znao gde drugde da stavim. U Beogradu se u petak i subotu (20 i 21) odrzava BAV - Beogradski astronomski vikend (Narodna opservatorija na Kalemegdanu), pa ko je zainteresovan neka se oseca slobodnim i dodje. PS Ulaz je slobodan. Ocekuje se velika guzva, a videcemo da li ce je biti ;)))
zvezde.105 nenad,
Astronomi se spore da li na mesečevim polarnim kapama ima vode (leda) ili ne. Konačni odgovor će izgleda morati da sačeka kraj godine kada će se "otići" na lice mesta. A Dry Moon After All? A new report, published in Science for June 6th, suggests that there might not be any water at the lunar poles after all. Radar echoes collected during the Clementine mission in April 1994 hinted that patches of ice might lie near the lunar south pole, mixed with dust in the frigid floors of permanently shadowed craters. But additional radar work with the 1,000-foot Arecibo radio dish has dimmed that prospect. Exploiting favorable Earth-Moon geometry in 1992, Nicholas J. S. Stacy (Defense Science and Technology Organization, Australia), Donald Campbell (Cornell University), and Peter Ford (MIT) used Arecibo's radar beam to peer into the shadowed craters. The presence of water ice would have changed the returning beam's polarization in a telltale way, but that's not what happened. "We don't see anything that suggests ice," says Campbell. However, Clementine scientists are standing by their results. The truth may be learned later this year, when a spacecraft called Lunar Prospector returns to the Moon to conduct a sensitive search for ice in the polar regions. If the Moon proves to be bone dry, as the Arecibo data suggest, it would place stringent constraints on the amount of water that could be delivered to the lunar surface by infalling comets -- miniature or otherwise.
zvezde.106 nenad,
Ulazak letelice Galilej u atmosferu Jupitera rezultirao je neočekivanim ishodom - ali nova merenja pokazuju da gasoviti džin ipak sadrži puno vode, a da je stiacaj okolnosti doveo do toga da letelica prođe kroz jedan od malih i retkih delova gde vlage nema. Jupiter: Wet and Dry Results from the Galileo spacecraft have restored scientists' belief that the clouds of Jupiter contain water. This view had been shaken when Galileo's probe found virtually no water during its December 1995 descent into the clouds. However, Galileo's near-infrared mapper has found some areas so humid that, according to investigator Robert Carlson (Jet Propulsion Laboratory), "it's either going to rain or it's raining right now." Apparently the probe chanced to enter the atmosphere in one of a few very dry parcels, which together cover only about 2% to 5% of the planet. These dry spots appear to be areas of downwelling gas. "Winds rise from the deep atmosphere and lose water and ammonia," explains Glenn Orton (JPL). "At the top, when they converge and drop back down, nothing is left to condense into clouds, and a dry clearing is created."