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#1
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Stupid question
Can someone help me understand this ?
The powerful telescopes are supposed to see in the past. OK, I get thet. If you look at a distant star, you catch the light it emitted one year ago if it is at one light-year distance. But you cannot see the light it emitted 2 years ago, for that light has already travelled past you. Correct ? Now, some say they can watch light coming from stars created just after the big bang. This I cannot understand, because that light should have travelled past us already, from the original point. Please explain ... |
#2
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Albert wrote in news:41743ba2$0$29565
: Can someone help me understand this ? The powerful telescopes are supposed to see in the past. OK, I get thet. If you look at a distant star, you catch the light it emitted one year ago if it is at one light-year distance. But you cannot see the light it emitted 2 years ago, for that light has already travelled past you. Correct ? Now, some say they can watch light coming from stars created just after the big bang. This I cannot understand, because that light should have travelled past us already, from the original point. Please explain ... Read the FAQ section: http://www.astro.ucla.edu/~wright/cosmolog.htm LK. |
#3
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Simple, does not our own star ( the sun ) shine all the time? Those Stars
where shining for many many millions of years. So while we are looking at a star that's maybe 12 billion lightyears away, we are most likly seeing the light that it released anytime during it's long lift span. -- "And for the second time in four million years, the monolith awoke." Arthur C.Clarke 2062dyssey three SIAR http://starlords.netfirms.com Telescope Buyers FAQ http://home.inreach.com/starlord Bishop's Car Fund http://www.bishopcarfund.netfirms.com/ "Albert" wrote in message ... Can someone help me understand this ? The powerful telescopes are supposed to see in the past. OK, I get thet. If you look at a distant star, you catch the light it emitted one year ago if it is at one light-year distance. But you cannot see the light it emitted 2 years ago, for that light has already travelled past you. Correct ? Now, some say they can watch light coming from stars created just after the big bang. This I cannot understand, because that light should have travelled past us already, from the original point. Please explain ... --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.775 / Virus Database: 522 - Release Date: 10/8/04 |
#4
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Thank you, but I cannot find any answer in the web site.
We see the light from the sun which was emitted 8 minutes ago. The light emitted 10 minutes ago cannot be seen. The question is at what distance are we from the point of big bang ? If it is 10 billion light years, then we can see what happened in the past at that point 10 billion years ago, but there is probably nothing left there. The matter has gone away, and the interesting information has travelled past us during the travel to reach a distance of 10 billion light years ... starlord wrote: Simple, does not our own star ( the sun ) shine all the time? Those Stars where shining for many many millions of years. So while we are looking at a star that's maybe 12 billion lightyears away, we are most likly seeing the light that it released anytime during it's long lift span. -- "And for the second time in four million years, the monolith awoke." Arthur C.Clarke 2062dyssey three SIAR http://starlords.netfirms.com Telescope Buyers FAQ http://home.inreach.com/starlord Bishop's Car Fund http://www.bishopcarfund.netfirms.com/ "Albert" wrote in message ... Can someone help me understand this ? The powerful telescopes are supposed to see in the past. OK, I get thet. If you look at a distant star, you catch the light it emitted one year ago if it is at one light-year distance. But you cannot see the light it emitted 2 years ago, for that light has already travelled past you. Correct ? Now, some say they can watch light coming from stars created just after the big bang. This I cannot understand, because that light should have travelled past us already, from the original point. Please explain ... --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.775 / Virus Database: 522 - Release Date: 10/8/04 |
#5
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"Albert" wrote in message ... Thank you, but I cannot find any answer in the web site. We see the light from the sun which was emitted 8 minutes ago. The light emitted 10 minutes ago cannot be seen. The question is at what distance are we from the point of big bang ? If it is 10 billion light years, then we can see what happened in the past at that point 10 billion years ago, but there is probably nothing left there. The matter has gone away, and the interesting information has travelled past us during the travel to reach a distance of 10 billion light years ... Firstly, the big bang happened everywhere simultaneously - there was no centre. The standard analogy is that of a balloon being inflated from a point - any point on the surface could be considered as the centre of the expansion. If you imagine a dot on the balloon, at the start all of the balloons surface is right next to the point, and as the balloon expands it appears (to anybody at the point on the ballloon) that all otheer points are receding away from it. Any point on the balloon can equally well be considered the centre. So which ever way you look you are looking in the direction of the centre of the big bang, and if you look far enough (back in time) you are seeing the big bang itself. As to the distance away it is, same argument. If the big bang happened 15 billion years ago, and you look in any direction, what you will see 15 billion light years away is the big bang. Its actually a little more complicated than this, as you may imagine, but this is the basic argument. HTH Peter Webb |
#6
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On Mon, 18 Oct 2004 23:54:42 +0200, Albert
wrote: Can someone help me understand this ? The powerful telescopes are supposed to see in the past. OK, I get thet. If you look at a distant star, you catch the light it emitted one year ago if it is at one light-year distance. Absolutely. Actually, the speed of light is constant but finite. If we were in the same room, you would see me as I was just a few billionth of a second ago!! No matter how close, there is always a delay. It is just like the ( delicate ) sound of thunder during a thunderstorm: there is a delay between the time we see the lightning and the time we HEAR it depending on how far away it is (sound travel at 340 meters per second). Remember that there is already a delay between the time the lighting does happen and the time we see it! So, because Alpha Centauri is 4.3 light-years away, we see it as it was 4.3 years ago. The most distant quasars are about 13 billions light-years away so we know that there was something in the universe 13 billions years ago. But you cannot see the light it emitted 2 years ago, for that light has already travelled past you. Correct ? Absolutely again! Now, some say they can watch light coming from stars created just after the big bang. From quasars actually, here is an example: http://antwrp.gsfc.nasa.gov/apod/ap000419.html This I cannot understand, because that light should have travelled past us already, from the original point. There was an original point but as the universe is expanding, that point is now a sphere all around us. There is a misconception that the Big Bang exploded into space. It did not. There was no space at that time: the Universe create it's own space during it's expansion... If you think that one day, with a super-super telescope we will be able to see some kind of Big Bang like a super-super novae then think again: it can not happen because at that time we were INSIDE the "cosmic egg". All we can expect to see is a kind of shell of light around us. And yes, there is one: http://map.gsfc.nasa.gov/m_uni/uni_101Flucts.html Please explain ... It took thousands of years for humankind to understand that ( and yet we are not sure ). Don't be sorry if you can't understand in just a few minutes.... Have a good night! Benoît... |
#7
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Darn it Peter, thats exactly what I was going to say!!
In fact this question (again definitely not stupid) resolved a problem I had in visualizing the BB (Big Bang). I couldn't figure out satisfactory how the Universe started without immediately collapsing back into a BH (Black Hole). Clearly the reasoning here had to be the expansion of Space was literally pulling the Universe out of the primeval singularity at a rate faster than light speed. Without this FTLS expansion the Universe would have had nowhere to go - (in the most absolute way imaginable), which would have caused a BH. Gravity therefore was unable to catch up with enough matter/energy to return to its original singularity state, and still is without normal stellar evolution. This is why the further back we go the faster "That region of the Universe" is moving away from us. Taking this a little further, it also means the tiny bits of atoms or sub atomic particles were being created right outa the energy fluctuations of the intense gravity fields in the first few seconds of the BB. - way cool - no? The process would similar to an analogy of condensation, as this incredible expansion equals fantastic cooling. There is a predicted background radiation temperature of 3 degrees Kelvin, if the Universe is about 20 billion years old and the expansion rate is what it is. And this temperature has since been confirmed, and it is also coming from all directions equally. We are all getting a very light microwave tan. Regards Robert "Peter Webb" wrote in message u... "Albert" wrote in message ... Thank you, but I cannot find any answer in the web site. We see the light from the sun which was emitted 8 minutes ago. The light emitted 10 minutes ago cannot be seen. The question is at what distance are we from the point of big bang ? If it is 10 billion light years, then we can see what happened in the past at that point 10 billion years ago, but there is probably nothing left there. The matter has gone away, and the interesting information has travelled past us during the travel to reach a distance of 10 billion light years ... Firstly, the big bang happened everywhere simultaneously - there was no centre. The standard analogy is that of a balloon being inflated from a point - any point on the surface could be considered as the centre of the expansion. If you imagine a dot on the balloon, at the start all of the balloons surface is right next to the point, and as the balloon expands it appears (to anybody at the point on the ballloon) that all otheer points are receding away from it. Any point on the balloon can equally well be considered the centre. So which ever way you look you are looking in the direction of the centre of the big bang, and if you look far enough (back in time) you are seeing the big bang itself. As to the distance away it is, same argument. If the big bang happened 15 billion years ago, and you look in any direction, what you will see 15 billion light years away is the big bang. Its actually a little more complicated than this, as you may imagine, but this is the basic argument. HTH Peter Webb --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.773 / Virus Database: 520 - Release Date: 05/10/2004 ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#8
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"Albert" wrote in message ... Can someone help me understand this ? The powerful telescopes are supposed to see in the past. OK, I get thet. If you look at a distant star, you catch the light it emitted one year ago if it is at one light-year distance. But you cannot see the light it emitted 2 years ago, for that light has already travelled past you. Correct ? Now, some say they can watch light coming from stars created just after the big bang. This I cannot understand, because that light should have travelled past us already, from the original point. Please explain ... after the big bang (or during), space expanded at higher than lightspeed speed. |
#9
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md wrote: "Albert" wrote in message ... Can someone help me understand this ? The powerful telescopes are supposed to see in the past. OK, I get thet. If you look at a distant star, you catch the light it emitted one year ago if it is at one light-year distance. But you cannot see the light it emitted 2 years ago, for that light has already travelled past you. Correct ? Now, some say they can watch light coming from stars created just after the big bang. This I cannot understand, because that light should have travelled past us already, from the original point. Please explain ... after the big bang (or during), space expanded at higher than lightspeed speed. Forbidden subject. |
#10
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Please explain ...
after the big bang (or during), space expanded at higher than lightspeed speed. Forbidden subject. Explain!!!!!!!!!!!! _______ Blog, or dog? Who knows. But if you see my lost pup, please ping me! A HREF="http://journals.aol.com/virginiaz/DreamingofLeonardo"http://journal s.aol.com/virginiaz/DreamingofLeonardo/A |
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