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I recently watched a program on the Science network about the history of the universe, and a representative from Hubble said that pointing the Hubble Telescope into deep space represented looking back in time. What does this mean, exactly? It's not a literal statement, is it? Does it relate to how long light takes to reach us? I'm just getting into learning about the cosmos, so please help me! Thanks.
Yes, it does relate to the speed of light. And, yes, it is literal. However, it doesn't mean we are seeing what happened on earth back in time.
To put simply. Something 10 lightyears away, a star. When we see the light from that star, we are seeing the light it made 10 years ago. It may look like a white dwarf now, but between the time it took for the light to reach our eyes, that star could have died.
Does that make sense?
I took alot of astronomy in college and I can guanrantee you that when you look up in the sky, you are not seeing the stars or other distant objects as they are now, but what they looked light when the light that is hitting your eyes now was generated from their surface, this could be billions of years ago.
When you look at the Sun (don't make it a habit), you are seeing it as it was about 8 minutes ago.
i would argue that it is be meaningless to say that how we see the stars is not how they actually are. It doesn't really confer any actual information.
i would argue that it is be meaningless to say that how we see the stars is not how they actually are. It doesn't really confer any actual information.
This might be a little too philosophical though
Hmm... I see your point... I think... correct me if I'm wrong.
Since we can't travel at the speed of light, then how we see them, is how they exist from our point of refrence. Because the information we recieve is however old we think it is, and if we sent a deep space radio telemetry satelight to send us back information, that would take even longer, then how we observe anything through a telescope might as well be exactly how it is, because that light is the closest to a present reality we could ever experience here on Earth.
Or, at least, that's what I think you are saying.
But, because of the speed of light, from the stars' point of refrence, we are behind, but it really doesn't make any difference for us. (except a lot of headaches)
The knowledge that the image of a star is something that reflects past, not current reality is an important bit of knowledge to the science of astronomy. In determing how long it takes for the "image" of a star to get here, and how that image presents itself, we can draw scientific conclusions about the universe. In other words, we can learn things about the universe by knowing that what we are seeing is not present reality, but reality as it was sometime in the past. For example, by looking at the spectrum of the light from a distant star, we can learn something about its composition and its direction of travel.
We can also make some judgements about the size of our universe, because we find that images of stars are never are older than a certain age, and this might mean that the universe is no older than the oldest inages we see, or that there are objects out there that are much older but whose light has not got to us yet.
The more we know about what goes on in the universe, the closer we are to knowing about the true nature of its, and our own, existence. And we are just beginning in our quest.
We can also make some judgements about the size of our universe, because we find that images of stars are never are older than a certain age, and this might mean that the universe is no older than the oldest inages we see, or that there are objects out there that are much older but whose light has not got to us yet.
Or, that light cannot travel a certain distance, or plenty of other theories.
When it comes right down to it, by simply staying on Earth, we have no way of proving anything, and theories is all we can come up with.
I think it's a waste of time. We are investing so much money and time and effort on something that can't possibly help us right now. Why not cure cancer, for all you know, someone that has cancer could discover faster-than-light travel if he were to live 10 years longer. I mean, it was a farmer boy who invented the television by looking at rows of corn, so why can't we see that anyone could discover the next thing to further us, and work on saving people instead of making pointless theories?
Its amazing to me that there are actually arguments in favor of the notion that the study of astronomy is pointless. We cannot live on this plant forever, it is doomed by forces in the universe that will eventually destroy it. If we don't advance far enough in our study of the universe before these catastrophic events occur, all human life could be lost. What could be more important?
Okay, I think I'm getting a better understanding of it now. But what about when we use a telescope? How does that effect what "time" we are seeing? When we look through a telescope at something 1,000 light years away, are we still seeing the light from 1,000 years ago, or does the magnification affect it somehow?
I think it's a waste of time. We are investing so much money and time and effort on something that can't possibly help us right now. Why not cure cancer, for all you know, someone that has cancer could discover faster-than-light travel if he were to live 10 years longer. I mean, it was a farmer boy who invented the television by looking at rows of corn, so why can't we see that anyone could discover the next thing to further us, and work on saving people instead of making pointless theories?
This is a complete non-sequitur. Many of our breakthroughs in medical science have a direct correlation with breaththroughs in the technologies of our other sciences. Cures for cancer won't come from research in a scientific vacuum. Think of the way that discovering X-Rays - not a medical discovery, by the way - helped us with, well, obviously X-Rays. How many people's lives have been saved due to that?
Truth is, all of these things work in connection with one another, and we should encourage the advancement of most all sciences, since they end up helping humanity in most circumstances. It isn't just people looking into space for the sake of it (i.e. a waste of time). That is a quite monstrous assertion, and it is unenlightened dogma.
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