ASTRONOMIJA

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omar little
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#101 Re: ASTRONOMIJA

Post by omar little » 25/04/2008 13:35

GALAXIES GONE WILD!

Fotografije mozete pogledati ovdje: http://www.spacetelescope.org/news/html/heic0810.html
Interacting galaxies are found throughout the Universe, sometimes as dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that result in new galaxies. A series of 59 new images of colliding galaxies has been released from the several terabytes of archived raw images from the NASA/ESA Hubble Space Telescope to mark the 18th anniversary of the telescope’s launch. This is the largest collection of Hubble images ever released to the public simultaneously.

Galaxy mergers, which were more common in the early Universe than they are today, are thought to be one of the main driving forces for cosmic evolution, turning on quasars, sparking frenetic star births and explosive stellar deaths. Even apparently isolated galaxies will show signs in their internal structure that they have experienced one or more mergers in their past. Each of the various merging galaxies in this series of images is a snapshot of a different instant in the long interaction process.

Our own Milky Way contains the debris of the many smaller galaxies it has encountered and devoured in the past, and it is currently absorbing the Sagittarius dwarf elliptical galaxy. In turn, it looks as if our Milky Way will be subsumed into its giant neighbour, the Andromeda galaxy, resulting in an elliptical galaxy, dubbed "Milkomeda", the new home for the Earth, the Sun and the rest of the Solar System in about two billion years time. The two galaxies are currently rushing towards each other at approximately 500,000 kilometres per hour.

Cutting-edge observations and sophisticated computer models, such as those pioneered by the two Estonian brothers Alar Toomre and Juri Toomre in the 1970s, demonstrate that galaxy collisions are far more common than previously thought. Interactions are slow stately affairs, despite the typically high relative speeds of the interacting galaxies, taking hundreds of millions of years to complete. The interactions usually follow the same progression, and are driven by the tidal pull of gravity. Actual collisions between stars are rare as so much of a galaxy is simply empty space, but as the gravitational webs linking the stars in each galaxy begin to mesh, strong tidal effects disrupt and distort the old patterns leading to new structures, and finally to a new stable configuration.

The pull of the Moon that produces the twice-daily rise and fall of the Earth’s oceans illustrates the nature of tidal interactions. Tides between galaxies are much more disruptive than oceanic tides for two main reasons. Firstly, stars in galaxies, unlike the matter that makes up the Earth, are bound together only by the force of gravity. Secondly, galaxies can pass much closer to each other, relative to their size, than do the Earth and the Moon. The billions of stars in each interacting galaxy move individually, following the pull of gravity from all the other stars, so the interwoven tidal forces can produce the most intricate and varied effects as galaxies pass close to each other.

Typically the first tentative sign of an interaction will be a bridge of matter as the first gentle tugs of gravity tease out dust and gas from the approaching galaxies (IC 2810). As the outer reaches of the galaxies begin to intermingle, long streamers of gas and dust, known as tidal tails, stretch out and sweep back to wrap around the cores (NGC 6786, UCG 335, NGC 6050). These long, often spectacular, tidal tails are the signature of an interaction and can persist long after the main action is over. As the galaxy cores approach each other their gas and dust clouds are buffeted and accelerated dramatically by the conflicting pull of matter from all directions (NGC 6621, NGC 5256). These forces can result in shockwaves rippling through the interstellar clouds (ARP 148). Gas and dust are siphoned into the active central regions, fuelling bursts of star formation that appear as characteristic blue knots of young stars (NGC 454). As the clouds of dust build they are heated so that they radiate strongly, becoming some of the brightest (luminous and ultraluminous) infrared objects (APG 220) in the sky.

These objects emit up to several thousand billion times the luminosity of our Sun. They are the most rapidly star-forming galaxies in today’s Universe and are linked to the occurrence of quasars. Unlike standard spiral galaxies like the Milky Way, which radiate from stars and hot gas distributed over their entire span of perhaps 100 000 light-years, the energy in luminous and ultraluminous infrared galaxies is primarily generated within their central portion, over an extent of 1000 to 10,000 light-years. This energy emanates both from vigorous star formation processes, which can generate up to a few hundred solar masses of new stars per year (in comparison, the Milky Way generates a few solar masses of new stars per year), and from massive accreting black holes, a million to a billion times the mass of the Sun, in the central region.

Intense star formation regions and high levels of infrared and far-infrared radiation are typical of the most active central period of the interaction and are seen in many of the objects in this release. Other visible signs of an interaction are disruptions to the galaxy nuclei (NGC 3256, NGC 17). This disruption may persist long after the interaction is over, both for the case where a larger galaxy has swallowed a much smaller companion and where two more closely matched galaxies have finally separated.

Most of the 59 new Hubble images are part of a large investigation of luminous and ultraluminous infrared galaxies called the GOALS project (Great Observatories All-sky LIRG Survey). This survey combines observations from Hubble, the NASA Spitzer Space Observatory, the NASA Chandra X-Ray Observatory and NASA Galaxy Explorer. The Hubble observations are led by Professor Aaron S. Evans from the University of Virginia and the National Radio Astronomy Observatory (USA).

A number of the interacting galaxies seen here are included in the The Atlas of Peculiar Galaxies, a remarkable catalogue produced by the astronomer Halton Arp in the mid-1960s that built on work by B.A. Vorontsov-Velyaminov from 1959. Arp compiled the catalogue in a pioneering attempt to solve the mystery of the bizarre shapes of galaxies observed by ground-based telescopes. Today, the peculiar structures seen by Arp and others are well understood as the result of complex gravitational interactions.


policy
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#102 Re: ASTRONOMIJA

Post by policy » 25/04/2008 13:55

e hajdemo se sada lijepo spustiti na planetu Zemlju, u drzavu koju od milja zovu Bosna i Hercegovina i postaviti jedno lijepo pitanje: kako da vratimo, kako da uspostavimo, institucionaliziramo rad u astronomiji u BiH. Astronomsko univeriztetsko drustvo koje je postojalo prije rata, koje je vodila grupa entuzijasta na celu sa Muhamedom Muminovicem je vodila jednu od najjacih amaterskih astronosmkih opservatorija u ovom dijelu svijeta - Colina Kapa. Sada se stvara kriticna masa ljudi, na celu sa Muhamedom Muminovicem, koja zeli obnoviti tu opservatoriju te dodati jos neke sadrzaje. Dakle, sta mozete vi uraditi za ovu misiju naseg zivota?

Svaka cast liku koji je postavio ovu temu.

emra_a
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#103 Re: ASTRONOMIJA

Post by emra_a » 09/05/2008 03:03

mene fasciniraju te tzv crne rupe,a i svemir uopceno.Zamisljam jezivu situaciju..zamislite radite kao astronaut i dok ste gore nesto se pokvari,sta ja znam,,i vi "odletite"...koliko bi dugo mogli "lebditi" svemirom prije nego sto bi preminuli? :D

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ljubav_aha
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#104 Re: ASTRONOMIJA

Post by ljubav_aha » 09/05/2008 03:51

policy wrote:e hajdemo se sada lijepo spustiti na planetu Zemlju, u drzavu koju od milja zovu Bosna i Hercegovina i postaviti jedno lijepo pitanje: kako da vratimo, kako da uspostavimo, institucionaliziramo rad u astronomiji u BiH. Astronomsko univeriztetsko drustvo koje je postojalo prije rata, koje je vodila grupa entuzijasta na celu sa Muhamedom Muminovicem je vodila jednu od najjacih amaterskih astronosmkih opservatorija u ovom dijelu svijeta - Colina Kapa. Sada se stvara kriticna masa ljudi, na celu sa Muhamedom Muminovicem, koja zeli obnoviti tu opservatoriju te dodati jos neke sadrzaje. Dakle, sta mozete vi uraditi za ovu misiju naseg zivota?

Svaka cast liku koji je postavio ovu temu.

http://www.astronomija.co.yu/razno/astr ... ju1203.htm

dio iz clanka :

" Nakon rata počeo sam da radim u Federalnom meteorološkom zavodu obzirom da nije bilo daljeg finansiranja organizacije u kojoj sam bio zaposlen. Tu sam se izborio za formiranje Sektora za astronomiju u kome su pored mene još dvije osobe. Obzirom da ne raspolažemo sa nikakvim instrumentima, to je rad uglavnom za kompjuterom, Internet, obavljanje osnovnih astronomskih proračuna i sl. Ujedno radim kao pomoćnik direktora za međunarodnu saradnju pa dosta putujem. Astronomiju održavam na nekoj vrsti “stand by” aranžmana čekajući neka bolja vremena. Bilo je i nekih inicijativa za nabavku opreme ali ih nisam prihvatao jer su bile na skromnom nivou. Naime, neozbiljno bi mi bilo da se vraćam na totalni amaterski početak koji mogu raditi i bez oficijelne pomoći. "

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StLouis
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#105 Re: ASTRONOMIJA

Post by StLouis » 09/05/2008 05:03

emra_a wrote:mene fasciniraju te tzv crne rupe,a i svemir uopceno.Zamisljam jezivu situaciju..zamislite radite kao astronaut i dok ste gore nesto se pokvari,sta ja znam,,i vi "odletite"...koliko bi dugo mogli "lebditi" svemirom prije nego sto bi preminuli? :D
e, ovo i meni na um padne svaki put kada gledam neku emisju o astronomiji, dje's zavrsit'?? ajme majko, kud volontira, bem ti jupiter i milky way :D

Postavljacu teme veliki pozdrav! :thumbup:

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Arminovski
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#106 Re: ASTRONOMIJA

Post by Arminovski » 09/05/2008 12:54

emra_a wrote:mene fasciniraju te tzv crne rupe,a i svemir uopceno.Zamisljam jezivu situaciju..zamislite radite kao astronaut i dok ste gore nesto se pokvari,sta ja znam,,i vi "odletite"...koliko bi dugo mogli "lebditi" svemirom prije nego sto bi preminuli? :D
Dok bi nestalo vazduha :)

Ovo je jos jeziviji scenario:
http://www.aerospaceweb.org/question/at ... 0291.shtml

-------------------------------------------------------------------------------------------------------------------------------------

Za sve koji se interesuju preporucio bi stranicu: http://www.astronomynow.com

emra_a
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#107 Re: ASTRONOMIJA

Post by emra_a » 09/05/2008 13:36

znaci covjeka moze maksimalno par sekundi izdrzat? cuj...ja citala odgovor jednog astronauta gdje kaze drugacije :D t.j nastavio bi lebditi,i da postoje pomocna sredstva u tom slucaju..bacis nesto ka jednoj strani i onda se tjelo okrene ka tamo ,,i tako bi se mogao jedino vratiti stationu
Last edited by emra_a on 09/05/2008 13:40, edited 1 time in total.

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ljubav_aha
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#108 Re: ASTRONOMIJA

Post by ljubav_aha » 09/05/2008 13:39

svaki astroanut je izlozen nejverovatnim zracenjima i ostalim elementima tokom putovanja,ljubav je pokretac svih misija van planete zemlje ;-)

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Fiore
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#109 Re: ASTRONOMIJA

Post by Fiore » 09/05/2008 13:58

ljubav_aha wrote:
policy wrote:e hajdemo se sada lijepo spustiti na planetu Zemlju, u drzavu koju od milja zovu Bosna i Hercegovina i postaviti jedno lijepo pitanje: kako da vratimo, kako da uspostavimo, institucionaliziramo rad u astronomiji u BiH. Astronomsko univeriztetsko drustvo koje je postojalo prije rata, koje je vodila grupa entuzijasta na celu sa Muhamedom Muminovicem je vodila jednu od najjacih amaterskih astronosmkih opservatorija u ovom dijelu svijeta - Colina Kapa. Sada se stvara kriticna masa ljudi, na celu sa Muhamedom Muminovicem, koja zeli obnoviti tu opservatoriju te dodati jos neke sadrzaje. Dakle, sta mozete vi uraditi za ovu misiju naseg zivota?

Svaka cast liku koji je postavio ovu temu.

http://www.astronomija.co.yu/razno/astr ... ju1203.htm

dio iz clanka :

" Nakon rata počeo sam da radim u Federalnom meteorološkom zavodu obzirom da nije bilo daljeg finansiranja organizacije u kojoj sam bio zaposlen. Tu sam se izborio za formiranje Sektora za astronomiju u kome su pored mene još dvije osobe. Obzirom da ne raspolažemo sa nikakvim instrumentima, to je rad uglavnom za kompjuterom, Internet, obavljanje osnovnih astronomskih proračuna i sl. Ujedno radim kao pomoćnik direktora za međunarodnu saradnju pa dosta putujem. Astronomiju održavam na nekoj vrsti “stand by” aranžmana čekajući neka bolja vremena. Bilo je i nekih inicijativa za nabavku opreme ali ih nisam prihvatao jer su bile na skromnom nivou. Naime, neozbiljno bi mi bilo da se vraćam na totalni amaterski početak koji mogu raditi i bez oficijelne pomoći. "
Nek se ima love za seminare i sl.. :skoljka:

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Arminovski
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#110 Re: ASTRONOMIJA

Post by Arminovski » 10/05/2008 12:49

emra_a wrote:znaci covjeka moze maksimalno par sekundi izdrzat? cuj...ja citala odgovor jednog astronauta gdje kaze drugacije :D t.j nastavio bi lebditi,i da postoje pomocna sredstva u tom slucaju..bacis nesto ka jednoj strani i onda se tjelo okrene ka tamo ,,i tako bi se mogao jedino vratiti stationu
Nisi ti mene shvatila. Ono prvo sto sam ti odgovorio "dok imas vazduha" je ako imas odijelo. Logicno je pa mozda nisam trebao ni da odgovorim. Bilo malo na salu.
Za ono drugo (ako nemas odijelo) nisi ni pitala ali je meni to jeziviji scenario i nema sanse da nastavis da lebdis tako vec umires vrlo brzo.

daj nam link da vidimo i mi ostali sta kaze astronaut jer za navedenu protumjeru sam skeptican dok mi ne das izvor.

emra_a
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#111 Re: ASTRONOMIJA

Post by emra_a » 10/05/2008 19:44

nisam uopste komentirala to sto kazes vec ono sto pise u tekstu koji si postirao,astronaut je govorio o situaciji kad imas odjelo

koji dio ti je cudan u tome sto je receno?

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Arminovski
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#112 Re: ASTRONOMIJA

Post by Arminovski » 10/05/2008 21:24

emra_a wrote:nisam uopste komentirala to sto kazes vec ono sto pise u tekstu koji si postirao,astronaut je govorio o situaciji kad imas odjelo

koji dio ti je cudan u tome sto je receno?
"i da postoje pomocna sredstva u tom slucaju..bacis nesto ka jednoj strani i onda se tjelo okrene ka tamo ,,i tako bi se mogao jedino vratiti stationu"

Sa ovim se ne slazem. Ne vidim da stoji ista o tome na linku koji sam postirao.
pozz.

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NIN
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#113 Re: ASTRONOMIJA

Post by NIN » 11/05/2008 13:52

Evo nesto zanimljivo:

Interactive Sky Chart

- Use our Interactive Sky Chart
- Submit astrophotos to SkyandTelescope.com's Photo Gallery
- Submit reader comments for blogs and selected articles
- Submit information about your astronomy club or event
- Sign up for our free SkyandTelescope.com e-newsletters

http://www.skyandtelescope.com/s?action ... scope.com/

Na postavljenom linku se mozete besplatno :D registrirati.

Pozdrav...

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Arminovski
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#114 Re: ASTRONOMIJA

Post by Arminovski » 11/05/2008 16:51

Poredite velicinu atoma, tranzistora, insekata sa planinama, planetama, zvijezdama.... svemirom.

Universcale

emra_a
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#115 Re: ASTRONOMIJA

Post by emra_a » 11/05/2008 17:21

Arminovski wrote:
emra_a wrote:nisam uopste komentirala to sto kazes vec ono sto pise u tekstu koji si postirao,astronaut je govorio o situaciji kad imas odjelo

koji dio ti je cudan u tome sto je receno?
"i da postoje pomocna sredstva u tom slucaju..bacis nesto ka jednoj strani i onda se tjelo okrene ka tamo ,,i tako bi se mogao jedino vratiti stationu"

Sa ovim se ne slazem. Ne vidim da stoji ista o tome na linku koji sam postirao.
pozz.
pa i ne pise u tvom..heh

procitala tvoj tekst,i onda samo napisala sta sam procitala negdje drugo


inace,kao sto vam je poznato"space tourism" vec postoji..prvi turista je bio neki jevrej,ne znam koliko ih je bilo do sad gore,no,da li bi vi ikada u buducnosti(kad bi imali finansijsku mogucnost) otisli into space kao turista?

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Arminovski
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#116 Re: ASTRONOMIJA

Post by Arminovski » 11/05/2008 18:52

emra_a wrote: procitala tvoj tekst,i onda samo napisala sta sam procitala negdje drugo
.
.
.
bacis nesto ka jednoj strani i onda se tjelo okrene ka tamo ,,i tako bi se mogao jedino vratiti stationu

Molim onda opet link jer mi je ta tvrdnja sumnjiva. Kao prvo, ne bi isla u istom pravcu kao i baceni objekt (ne znam sta to toliko ima astronaut da baci sa sebe i uz to dovoljno snazno da bi se mogao uopste pomjeriti neku znatnu distancu) vec u suprotnom (isti princip kao i kod rakete). Kao drugo, i kad bi ti uspjelo tvoj krajnji domet bi bila neka vrsta rotacije jer bi ti bilo tesko baciti doticni predmet tako da on tebe "odbaci" u zeljenom pravcu. Eto to je moje misljenje a ti dokazi da nisam u pravu :)

omar little
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#117 Re: ASTRONOMIJA

Post by omar little » 11/05/2008 20:14

emra_a wrote:
Arminovski wrote:
emra_a wrote:nisam uopste komentirala to sto kazes vec ono sto pise u tekstu koji si postirao,astronaut je govorio o situaciji kad imas odjelo

koji dio ti je cudan u tome sto je receno?
"i da postoje pomocna sredstva u tom slucaju..bacis nesto ka jednoj strani i onda se tjelo okrene ka tamo ,,i tako bi se mogao jedino vratiti stationu"

Sa ovim se ne slazem. Ne vidim da stoji ista o tome na linku koji sam postirao.
pozz.
pa i ne pise u tvom..heh

procitala tvoj tekst,i onda samo napisala sta sam procitala negdje drugo


inace,kao sto vam je poznato"space tourism" vec postoji..prvi turista je bio neki jevrej,ne znam koliko ih je bilo do sad gore,no,da li bi vi ikada u buducnosti(kad bi imali finansijsku mogucnost) otisli into space kao turista?
Pa, zar postoji neko ko ne bi?!?

P.S.
Interesantno je da sam znala da se covjek preziva Tito (iz ocitih razloga mi je ostalo u pamcenju), da je multi-milioner, da je inzinjer i doktor financijskih nauka, da sam kad sam studirala financije ucila o njemu i njegovom Wilshire indeksu ali nikad nisam cula da ga se identificira i opisuje sa "neki Jevrej"...

walkabout
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#118 Re: ASTRONOMIJA

Post by walkabout » 13/05/2008 23:49

ovo nadjoh maloprije...

umjesto ulaganja u teleskope...bolje kupiti najmocniji kompjuter/malu mrezu, najvece monitore/ekrane, i koristiti najbrzu internet konekciju...umjesto starih dobrih teleskopa... :roll:

-------------------------------------

A free program launched today will effectively turn every computer that downloads it into a mini-planetarium capable of displaying high resolution images of millions of stars, planets and other celestial bodies.

The project, called the WorldWide Telescope (WWT), is the result of several years of hard labour by a small team at Microsoft Research, the software company's key R&D centre.

It has drawn lavish praise from some of the world's leading space scientists and educators, including Dr Roy Gould of the Harvard-Smithsonian Centre for Astrophysics.

"Galileo's telescope started to give us views of the universe that no one else had seen before and we started asking what was out there and why. And I think the WorldWide Telescope is going to do the same thing for the rest of us," he said in a telephone interview.

"In terms of pushing the envelope, this really pushes the envelope."

The program works in the same way as many online mapping tools, allowing users to zoom around on an interactive canvas combining images and data drawn from the world's leading astronomical research organisations.

At launch, the WWT has access to 12 terabytes of data - enough to fill the equivalent of 1.2 million books. But like the universe, this will expand as new images are added.

Dr Gould believes the WWT will give amateur astronomers and even complete novices an opportunity to assist the scientific community in furthering their research.

"This is going to change our relationship with the night sky in a significant way," he said.

WWT is being offered without strings attached from today as an educational tool and was created to honour the memory of the late Dr Jim Gray, a leading Microsoft computer scientist who was lost at sea in 2007.

Dr Gray believed that the vast amount of space data being collected would change astronomy from being an observational science into a computational one, said Dr Curtis Wong, a leading Microsoft research scientist and the head of the WWT project.

With the growth of the internet and the increasing processing power of standard computers, Gray could see the internet becoming the platform for a worldwide virtual observatory which anyone could use.

A key feature of the program is the ability of users - any user, not just the experts - to create rich media tours to showcase features found on the WWT database.

For instance, one of the tours takes you across the Martian landscape using images captured in the Mars Rover program.

"For millennia ... every different culture has their own story about the heavens," said Dr Wong in a telephone interview. "The WorldWide Telescope is an opportunity for people to create and share those stories."

The Microsoft project is being launched almost nine months after Google rolled out its Google Sky service, a layered map of astronomical images that its part of its Google Earth program.

But there is no sense of a space race between the two giants of the technology world. Both projects have no commercial application and exist as public service tools.

Dr Wong would not be drawn on making comparisons between the two although it has been previously reported that the WWT packs in much more data and imagery than its Google counterpart.

The WWT comes as a 20MB download and is available from the WorldWide Telescope site. The program only works on the Widows operating system.

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Sensei
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#119 Re: ASTRONOMIJA

Post by Sensei » 17/05/2008 07:51

...
Last edited by Sensei on 25/05/2019 17:50, edited 1 time in total.

guardian
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#120 Re: ASTRONOMIJA

Post by guardian » 22/05/2008 00:58

NASA TV ce direktno prenositi slijetanje Phoenix-a na Mars u nedjelju/ponedjeljak (pocinje u ponoc po centralnoevropskom vremenu, slijetanje je predvidjeno za ponedjeljak, 25.05., 1:53 poslije ponoci): http://www.nasa.gov/multimedia/nasatv/index.html

Phoenix je lansiran 04.08.2007. http://en.wikipedia.org/wiki/Phoenix_(spacecraft)

Image

omar little
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#121 Re: ASTRONOMIJA

Post by omar little » 24/05/2008 22:29

Scientists See Supernova in Action

A star trembled on the brink of eternity. Outwardly all was serene, but its inside was falling into chaos.

Far away on the day of Jan. 9, Earth time, a satellite telescope by the name of Swift, which happened to be gazing at the star’s galaxy, a smudge of stars 88 million light-years away in the constellation Lynx, recorded an unexpected burst of invisible X-rays 100 billion times as bright as the Sun.

Alicia Soderberg, a Princeton astronomer who had been using the NASA satellite to study the fading remains of a previous supernova explosion, received the startling results of that observation by e-mail while giving a talk in Michigan. Recognizing that this was something extraordinary, she sounded a worldwide alert.

In the following hours and days, as most of the big telescopes on Earth, and the Hubble Space Telescope and the Chandra X-ray Observatory watched from space, the star erupted into cataclysmic explosion known as a supernova, lighting up its galaxy and delighting astronomers who had never been able to catch an exploding star before it exploded.

“We caught the whole thing on tape, so to speak,” Dr. Soderberg said in an interview. “I truly won the astronomy lottery. A star in the galaxy exploded right in front of my eyes.”

She and 42 colleagues from around the world have now told the tale of this discovery in a paper in Nature to be published Thursday and in a telephone news conference Wednesday. The observations, they say, provide a new window into the process by which the most massive stars end their lives and give astronomers new clues on how to look for these rare events and catch them while they are still in their most explosive, formative stages.

Most supernovas, Dr. Soderberg explained, are discovered and classified by their visible light, but that typically does not happen until the explosion is a month or more old and has brightened enough to be seen over intergalactic distances.

The true fireworks, she said, happen much earlier when a shock wave from the imploding core hits the star’s surface, producing so-called breakout light, which lasts only a few minutes.

“The physics of the explosion is encoded in the breakout light,” Dr. Soderberg said, adding that the chance that the Swift telescope was observing during those moments was “unfathomable.” Astronomers now know, however, that X-rays from the breakout can be an early alert. “Supernova 2008D was the first to be found from its X-ray emission,” said Robert Kirshner, a supernova expert at the Harvard-Smithsonian Center for Astrophysics, referring to the supernova by its official name, “but if we build the right type of X-ray satellites, it won’t be the last supernova we find this way.”

“That is really what is so wonderful here,” he said.

So new were the X-rays, said Dr. Soderberg, that she and her collaborators did not know they were looking at an incipient supernova until a day or two later and ground-based telescopes had seen it grow in visible light.

“It was a baby supernova in that sense,” Dr. Soderberg said. “Here was an object brand new. At first we didn’t recognize it.”

The supernova was of a sort known as Type Ibc, the rarest and most luminous of the explosions caused by the collapse of the cores of massive stars, the astronomers have concluded. Another kind, known as Type Ia supernovas, are believed to result from the destruction of much smaller stars and are beloved of cosmologists who use them to track the expansion of the universe and effects of dark energy.

The star that died last January could have been 20 times as massive as the Sun or even bigger, Dr. Soderberg said. It was probably a type called a Wolf-Rayet star. They are very hot stars with surface temperatures of 50,000 degrees Fahrenheit or more and are often blowing gas away in strong winds. Dr. Soderberg described them as “very violent stars, very massive.”

Because it is gravity that stokes the thermonuclear furnace at the centers of stars, the more massive they are, the younger they die. In the case of a star 10 or 20 times as massive as the Sun, it could be only a few million years. “These stars live fast and die young. We don’t know if they leave a beautiful corpse,” Dr. Kirshner said.

Many of the elements necessary for life and its accessories, like carbon, oxygen, iron and gold, are produced in a thermonuclear frenzy during the final stages of these explosions, which then fling them into space to be incorporated into new stars, new planets, new creatures.

“If you’re wearing gold jewelry,” Dr. Kirshner said, “it came from a supernova explosion.”

Or as Joni Mitchell sang poetically and accurately, “We are stardust.”

walkabout
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#122 Re: ASTRONOMIJA

Post by walkabout » 25/05/2008 00:09

Kad smo vec kod eksplozija...imam jedno pitanje za one koji su bolje upoznati sa astronomijom.

Naime, imao sam nevjerovatno (i potpuno neocekivano i nenadano) iskustvo da sam, gledajuci u zvjezdano nocno nebo, golim okom vidio nesto sto sam sebi objasnio da nista ne moze biti drugo nego eksplozija zvijezde (ili necega (puno) veceg).

Skoro svi znamo kako izgleda kad meteorit udje u atmosferu, zapali se i ostavi svijetli trag na nebu, sve traje mozda nekoliko desetinki sekunde. Eh ovo sto sam vidio je bilo sasvim drugacije. Fokusiran na jedan dio nocnog neba ("Juzno" nebo je u pitanju, sto je nebitno), sto ponekad radim kad sam u prilici, negdje otprilike "pravo" iznad glave, u jednoj tacki, najednom primijetim "pojavu" "nove" zvijezde. Naravno da je iznenadjenje i u momentu se paznja poveca 10-ak puta.

Ali ta svijetla sicusna tacka poce da raste, relativno brzo, pojavise se sicusni kraci te "zvijezde" kako se povecavala a zatim i crna tacka/rupa u sredini nje savrsenog okruglog oblika koja se isto poce povecavati kako je i zvijezda "rasla" ali malo brze od nje tako da je na kraju "sustize" i zvijezde nestade na nebu. Sve skupa je trajalo mozda 1-2 sekunde, velicina koju je ta "nova zvijezda" dosegla je bilo oko "1-2 mm na nocnom nebu" - ne znam kako drugacije reci. Pogled mi je ostao prikovan za taj dio neba jos izvjesno vrijeme ali nista vise se nije desilo.

Ako ovaj opis nije dovoljno slikovit, mogu se potruditi i postaviti i crtez kako je to izgledalo.

Da li neko zna objasniti sta sam ja to vidio - po meni je to sigurno bila eksplozija ali cega? Sta je to eksplodiralo, i gdje, da se je moglo vidjeti golim okom na Zemlji?

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tranquil
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#123 Re: ASTRONOMIJA

Post by tranquil » 25/05/2008 14:09

walkabout wrote:Kad smo vec kod eksplozija...imam jedno pitanje za one koji su bolje upoznati sa astronomijom.

Naime, imao sam nevjerovatno (i potpuno neocekivano i nenadano) iskustvo da sam, gledajuci u zvjezdano nocno nebo, golim okom vidio nesto sto sam sebi objasnio da nista ne moze biti drugo nego eksplozija zvijezde (ili necega (puno) veceg).

Skoro svi znamo kako izgleda kad meteorit udje u atmosferu, zapali se i ostavi svijetli trag na nebu, sve traje mozda nekoliko desetinki sekunde. Eh ovo sto sam vidio je bilo sasvim drugacije. Fokusiran na jedan dio nocnog neba ("Juzno" nebo je u pitanju, sto je nebitno), sto ponekad radim kad sam u prilici, negdje otprilike "pravo" iznad glave, u jednoj tacki, najednom primijetim "pojavu" "nove" zvijezde. Naravno da je iznenadjenje i u momentu se paznja poveca 10-ak puta.

Ali ta svijetla sicusna tacka poce da raste, relativno brzo, pojavise se sicusni kraci te "zvijezde" kako se povecavala a zatim i crna tacka/rupa u sredini nje savrsenog okruglog oblika koja se isto poce povecavati kako je i zvijezda "rasla" ali malo brze od nje tako da je na kraju "sustize" i zvijezde nestade na nebu. Sve skupa je trajalo mozda 1-2 sekunde, velicina koju je ta "nova zvijezda" dosegla je bilo oko "1-2 mm na nocnom nebu" - ne znam kako drugacije reci. Pogled mi je ostao prikovan za taj dio neba jos izvjesno vrijeme ali nista vise se nije desilo.

Ako ovaj opis nije dovoljno slikovit, mogu se potruditi i postaviti i crtez kako je to izgledalo.

Da li neko zna objasniti sta sam ja to vidio - po meni je to sigurno bila eksplozija ali cega? Sta je to eksplodiralo, i gdje, da se je moglo vidjeti golim okom na Zemlji?
Eksplozije nove i supernove traju duže od 1-2 sekunde - evo u prethodnom tekstu kaže da je najjači dio jako kratak - nekoliko minuta :-D A da bi bile vidljive sa Zemlje, moraju biti u našoj galaksiji - obrati pažnju na prethodni tekst - ova supernova se desila u galaksiji udaljenoj 88.000.000 svjetlosnih godina i opet je viđena, naravno samo teleskopom. Ove u našoj galaksiji se mogu vidjeti na nebu, samo što se događaju jako rijetko - jednom u više vijekova.

Tako da ne znam šta bi moglo biti to što si vidio - možda bi ti odgovor mogli dati ne oni što se razumiju u astronomiju, nego oni što se razumiju u šta ja znam, meteorologiju (vezano i za meteore i za meteorološke fenomene - oluje, loptaste munje i sl. :)) ili možda halucinologiju :-)

walkabout
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#124 Re: ASTRONOMIJA

Post by walkabout » 25/05/2008 22:54

tranquil wrote: Eksplozije nove i supernove traju duže od 1-2 sekunde - evo u prethodnom tekstu kaže da je najjači dio jako kratak - nekoliko minuta :-D A da bi bile vidljive sa Zemlje, moraju biti u našoj galaksiji - obrati pažnju na prethodni tekst - ova supernova se desila u galaksiji udaljenoj 88.000.000 svjetlosnih godina i opet je viđena, naravno samo teleskopom. Ove u našoj galaksiji se mogu vidjeti na nebu, samo što se događaju jako rijetko - jednom u više vijekova.

Tako da ne znam šta bi moglo biti to što si vidio - možda bi ti odgovor mogli dati ne oni što se razumiju u astronomiju, nego oni što se razumiju u šta ja znam, meteorologiju (vezano i za meteore i za meteorološke fenomene - oluje, loptaste munje i sl. :)) ili možda halucinologiju :-)
hvala na odgovoru...koliko mogu da vidim, iskljucuje se mogucnost eksplozije nove/supernove, osim jednom u nekoliko vijekova...

glede drugog dijela odgovora...josh jedna potvrda da je diskusija nenadmasna disciplina na nasim prostorima...mora da je do mene...ali je dobro da se moja licna ocekivanja daju podesiti... :thumbup:

u medjuvremenu, jos jedna mogucnost :roll: ... da li je moguce da je to sto sam vidio bio meteorit ali koji je padao bash vertikalno prema mjestu posmatraca...zbunjuje me to sto je izgladalo bash daleko, "u razini zvijezda"...te ta pojava crne tacke/kruga/rupe u sredini koja se ubrzano prosiri i sve nestade u "trenu" kao sto je i doslo...

bicu zahvalan ako josh neko ponudi objasnjenje ili bar navede mogucnosti sto bi moglo biti...

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Arminovski
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#125 Re: ASTRONOMIJA

Post by Arminovski » 26/05/2008 00:00

Pozdrav

Nista definitivno od mene. Par mogucnosti. Uzeti sa dozom rezervacije.

I ja sam pomislio isto kao i ti, tj da je meteor (ne meteorit jer da je meteorit imao bi rupu na glavi hihihi. izvini nisam besserwisser ali sam morao (= ) ali me isto tako zbunjuje ta tacka koju navodis. Posto su ti meteori rijetko veci od par milimetara (velicine zrna pijeska) postoji mogucnost da je njegovu svjetlost bas zaklonila neka druga cestica na manjoj visini, onako kako zaklanjaju normalne zvijezde pa one trepere. Zasto je izgledalo kao da crna tacka raste? Ne znam, mozda zato sto si se ti u tom trenutku koncentrisao na tu tacku na nebu. Mozda je bilo obratno, tj da je meteor sagorijevao i postepeno se gasio (ispred pomenute cestice) a tvoj mozak je to "preveo" na povecavanje crne tacke. Oko duzine vremena (duze nego obicno), ponekad padaju i vise od nekoliko sekundi. Do sad sam tri puta u zivotu vidio meteor koji je padao najmanje 2-3 sekunde i jos se raspadao u atmosferi.

Pade mi na glupost i jedna druga stvar. Nerijetko su mi se desavale slicne stvari dok sam promatrao vedro nebo. Naime, ako gledas u jedan dio neba duze vremena, pojavljivace se nove zvijezde koje nisi vidio do tada. Ako je zvijezda jako slabe svjetlosti onda se mozda moze desiti da je to bila jedna od zIvijezda koje se golim okom mogu vidjeti samo ponekad tj one koje ih cestice u nasoj atmosferi vecinom zaklanjaju i da si ti vidio onaj rijetki trenutak kad je ta zvijezda bila vidljiva.

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Imam i ja jednu misteriju: Na Novu Godinu 1994. tamo negdje blizu sjevernog pola mrznuli smo se ja i jos par drugara napolju i kao iscekivali Novu (kako i zbog cega ne pitajte)... Posto je nebo bilo stvarno vedro svrljao sam pogledom po zvijezdama (navika) i ugledao nesto sto nikad prije nisam. Naime, u jednom trenutku ugledao sam svjetlost koja se kretala po nebu kao i sateliti/avioni samo malo brze i izgledala isto tako (danas vise nisam ni siguran da li je bila svjetlija od okolnih zvijezda). Nakon par sekundi ta svjetlost je iznenada promijenila pravac i to naglo i to me iznenadilo. Koji sekund kasnije promjena pravca na isti nacin i tako sve cik cak (nepravilan cik cak po nebu kao da udara u nesto svakih par sekundi). Sve se to odvijalo desetak sekundi i dok sam ja pozvao drugare da im pokazem izgubio sam iz vida taj objekt i vise ga nisam mogao naci na nebu. Sta bi ovo moglo biti? Halucinacija? :skoljka:

Prije pola godine negdje predvece vidio sam i nesto sto ne vjerujem da je bio avion jer se kretalo prebrzo a sto je preslo otprilike pola horizonta dok nije nestalo iza oblaka/brda. Mislim da je svjetlilo svojom svjetloscu jer je sunce bilo iza datog objekta tj ne meni iza ledja pa da vidim odsjaj metala... Asteroid okrznuo zemljinu atmosferu?
Last edited by Arminovski on 26/05/2008 00:22, edited 1 time in total.

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