Hubble Telescope images taken are billion years old?
2016-01-23 8:12 pm
The telescope takes photos of star millions of light years away, dows that mean the images we are seeeing are of light that has been emmited by it millions of year ago, so that also means they must have changed lot by present time?
回答 (11)
2016-01-23 9:16 pm
✔ 最佳答案
You are correct. When we look at stars, we are looking into the past. We don't know what they look like at this moment. Even the stars you can see with your eyes are images from the past. If you look at Betelgeuse (in the Orion constellation), you are looking at about 650 years in the past. For all we know, it could have died and exploded in a supernova today, but we would not know about it for 650 years.They say time travel is not possible, but you can observe the past just by looking up into the night sky. Even looking at the moon is looking at what it was 1.3 seconds ago.
2016-01-23 8:37 pm
Yes, the light has been traveling all that time, and the objects that far away have "now" evolved considerably. Actually this is extremely useful, because we can actually see the time evolution of the Universe from shortly after the Big Bang to the present, by looking out to different distances.
2016-01-23 9:04 pm
Yes, that's true. The further away an object is, the further back in time we see how that object *was*. It's possible that galaxies billions of light years away have changed much; while those closer in we may not notice any difference in what they would look like up close as compared to a few million years ago when their light left for Earth.
2016-01-23 8:51 pm
Yes, so the further away the objects are, the earlier in the history of Universe they existed- Quasars existed in an early stage of the Universe, so by looking at distant Quasars it is like looking at an image of our own creation billions of years ago.
If an advanced civilization exists among the site of those Quasars, they might be looking back at our creation! When we see the Andromeda Galaxy, it is over 2 million years ago.
If an advanced civilization exists among the site of those Quasars, they might be looking back at our creation! When we see the Andromeda Galaxy, it is over 2 million years ago.
2016-01-23 8:37 pm
Yes and yes.
However ...
we can never see them as they are - we can only see them as they were when the light left them.
The universe is thought to be about 13.8 billion years old.
An object that is 4.5 billion light years away is seen by us today by light that left it 4.5 billion years ago. Which is when our solar system was forming.
The most distant objects detected by the Hubble Space Telescope are about 13 billion light years from us. Light from those started on its journey to us about 13 billion years ago when the universe was less than 1 billion years old.
However ...
we can never see them as they are - we can only see them as they were when the light left them.
The universe is thought to be about 13.8 billion years old.
An object that is 4.5 billion light years away is seen by us today by light that left it 4.5 billion years ago. Which is when our solar system was forming.
The most distant objects detected by the Hubble Space Telescope are about 13 billion light years from us. Light from those started on its journey to us about 13 billion years ago when the universe was less than 1 billion years old.
2016-01-24 12:08 am
Your assumptions are correct. It's all about gaining a perspective of how far back in time the images portray.
2016-01-23 9:04 pm
Yes
2016-01-24 4:41 am
>> "The telescope takes photos of star millions of light years away, does that mean the images we are seeing are of light that has been emitted by it millions of year ago, so that also means they must have changed lot by present time."
It most certainly means that.
So, what's your point?
It most certainly means that.
So, what's your point?
2016-01-24 12:14 am
"Hubble Telescope images taken are billion years old?"
No, the *images* have just been taken, and are fresh and new.
"The telescope takes photos of star millions of light years away, [does] that mean the images we are seeing are of light that has been emmited by it millions of year ago,"
Think of the snapshot of a single image, as the arrival of a subway train. A whole bunch of people (photons) arrived, and they represent the cultures (spectrum) of their point of origin and the time that train stopped at their originating locale.
"so that also means they must have changed lot by present time?"
Does not mean "must have", means "may have" changed. Those stars, lots of them, look just like our own. Our star has not changed a whole lot in a million years, even 4 billion years has brought galactically-small (if important to us) changes in our solar system.
No, the *images* have just been taken, and are fresh and new.
"The telescope takes photos of star millions of light years away, [does] that mean the images we are seeing are of light that has been emmited by it millions of year ago,"
Think of the snapshot of a single image, as the arrival of a subway train. A whole bunch of people (photons) arrived, and they represent the cultures (spectrum) of their point of origin and the time that train stopped at their originating locale.
"so that also means they must have changed lot by present time?"
Does not mean "must have", means "may have" changed. Those stars, lots of them, look just like our own. Our star has not changed a whole lot in a million years, even 4 billion years has brought galactically-small (if important to us) changes in our solar system.
2016-01-25 1:59 pm
When you look at the palm of your out-stretched hand, it was really about 1 nanosecond old. Think of that. Light takes time to travel before reaching your eyeballs.
2016-01-23 9:47 pm
That's exactly right.
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