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| ||||| Thursday, March 07, 2002 - 08:01 pm Video showing on NASA TV at this time: "Visions of our Past: Hubble's Journey Back in Time." http://www.space.com/video/ Is there a transcript or article of this fascinating video please? Some of my friends do not have video capabilities at this time, and I would like to forward the dialogue from Scott Altman, John Grunsfeld and James Newman. Much appreciated. Oh-eh, just another question please. Can you describe, "back in time", of course the answer is obvious-- back in time... but Hubble (God willing), will it not be imaging what it sees as a reality for us - the present, the past being the time the image was captured? Of course light years play into this - the time it would take us to reach a point in light years... perhaps you can explain better in layman's terms please, if possible. | |
| ||||| Thursday, March 07, 2002 - 08:20 pm Betty, The point you raise is a point of considerable confusion to most people. When we look at things on earth, we see them happen while they are happening. This is because the light takes virtually no time to get to us. One way to understand what we mean by "back in time" is to consider a letter. You could recieve a letter from a friend on a Friday which says "Tuesday we are going to Paris". You understand that the trip occured before you got the letter because of the time it took for the letter to get from France to you. It is the same with light. The light from distant galaxies started on its trip to earth (in some cases) millions of years ago. It has been travelling very quickly for all this time. When the telescope takes a picture, it sees the light that just got here and sees what was going on back millions of years ago. Of course light years play into this (as you noticed) since one light year is the distance light travels in one year. It is about 6 trillion miles. That's pretty far for us, but right next door for space. The nearest stars are around 4 light years away. The sun is about 8 light minutes away (exceedingly close). So you see, there is no actual time-travel involved, it's just that the messenger (light) takes a while to deliver the message. | |
| ||||| Thursday, March 07, 2002 - 08:36 pm Betty, It looks as though that is a space.com production, since their logo is on it. Perhaps you thought it was done by NASATV because there is a NASATV link beneath the movie links. IF that is so, you would need to contact space.com | |
| ||||| Friday, March 08, 2002 - 12:59 am Thank you. I will need to digest this part Dave: "The light from distant galaxies started on its trip to earth (in some cases) millions of years ago. It has been travelling very quickly for all this time. When the telescope takes a picture, it sees the light that just got here and sees what was going on back millions of years ago." Thank you spacegrll for your help. Good wishes and continued success. | |
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