Because of the speed of light, are we really seeing what was years ago when we look up in the sky and why???

Answer 1

Yes, yes and yes, the people who answered your question were quite familiar with the night sky being a portal into the distant past.
I've been fascinated with the night sky and have studied books and articles on astronomy and astro-physics over the years just so I can try to keep up with current issues. In several bedrooms where I have lived, I have painted the night sky in deep, swirling cerulean blues and blacks with the comets(wasn't that neat we finally got to see some comets in the 1990's?) and galaxies, and shooting stars and suns and nebulae. The best, of course, is the images that have come in through the Hubble Telescope, such majesty and wonder, beyond my simple mind to grasp! Such distances, such an endless melange of mysteries and ideas to confront and wrap our minds around. You must love the sky as well, to ask such as you have. You must also be a teacher at heart. Thanks for your question.
--->>>Sincerely, UCSteve

Answer 2

Yes, when you look up into the sky and see stars you are seeing light that was emitted from those stars a long time ago. For instance, if you look up into the dark night time sky and see a star that is 100 light years away then you are seeing light from that star that left that star 100 years ago. This is because light travels at 186,000 miles per second (300,000 km per second) and 6 trillion miles per year. And during a sunny day you are feeling the warmth of the sun's radiation that left the sun 8 minutes and 19 seconds before.

Answer 3

Yes, amazing isn't it! A good analogy is available anywhere. Go to a big pool and throw in a rock. Watch the waves coming toward you. It takes a while before the wave information gets to the shore. So the shore only finds out about the rock long after the rock is on the bottom.

It is the same with the universe. We get the amazing chance to look at the past. A black hole swallowing a star ten billion years ago is seen here now, so long as it happened billions of light years away. Amazing!

Answer 4

The light from our Sun takes 8 minutes to get here - so we see the sun the way it was 8 minutes ago. The nearest star is about 6 light years away (light year = distance light travels in 1 year). We see that star as it was 6 years ago. The Hubble telescope has see stars and galaxies at the edge of the universe. When we look at these we are looking at the universe from the beginning of time - 6 billion years ago.
Think of it as in terms of the speed of sound (about 700 feet per second). When someone yells something and he is 700 feet away, we hear what he yelled 1 second ago, not instantaneously.

Answer 5

A good way of elaborating on what people said, it's like watching a baseball game and sitting in the upper deck or in the outfield bleachers. The batter swings, hits the ball - you'll notice that the ball is already flying in the air, by the time you hear the sound. You are actually hearing a past event, that has already occurred. The night sky is the same way - you are seeing past events, that have already occurred. Another example of this are fireworks...they explode, then you hear the sound later...you see the explosion first, because that is made up of light - sound comes after because sound is slower than light.

Answer 6

When you look into the night sky, you're seeing stars because of the light that travels from them to you. Now, it takes time for that light to reach you. Imagine you're looking at a star that is 6,000 light years away. You're seeing it as it was 6,000 years ago. When you look out across space, you're also looking back through time. That is why it is called spacetime. Information travels across spacetime at a maximum speed--the speed of light. Even when we look at the Sun, we see it as it was approx 8 minutes in the past. The moon, being lots closer, we see about a second and a half in the past.

Answer 7

Yes. Because space is big. Really big. Unbelievably, unimaginebly big. And even though light is fast (186, 000 miles per second) the nearest star (Proxima Centauri) is 4.2 light years away. That's 4.2 light years (186. 000 miles per second times the seconds in a year which is 60 seconds per minute times 60 minutes in an hour times 24 hours in a day times 365 days in a year), and a light year is 5,865,696,000,000 miles. And Proxima Centauri is 4.2 times that far. Meaning it takes the light 4.2 years to get here. And that's the closest one.

To answer the question again. Yes and because they're far far away.

Answer 8

Hard to say for sure. The speed of light is theory, not fact. It's not proveable. It's presented as fact, but it's not. It's very likely to be true, however, from a biblical standpoint, God created light before he created the sun. So who knows.

Answer 9

You're absolutely right; especially with regard to faraway galaxies, for which the light that we see them by was made in massive young stars whose lifetimes are much shorter than the time taken by their light to reach us. Most of those stars are *not* still there, and we can never know what they look like "now"!

That sounds depressing, but look at it this way-- seeing galaxies of stars as they were some time ago proportional to their distance gives us astronomers a vantage point on our universe that historians of human endeavors must envy. To be able to merely *look* directly into the past.

Stars live stable lifetimes (on the main sequence, thermostatically burning hydrogen into helium) that are proportional to the ratio (mass/luminosity). It makes sense-- divide total energy stored by the rate at which you use it up, and you get the time before you've used up your energy.

Because the stars have to liberate enough energy through fusion to balance their weight, more massive stars burn their energy a lot faster than smaller ones. Under more pressure, the most massive stars rip through their core hydrogen supply in only a tiny fraction of the time that it takes for the smallest stars.

For the Sun (on the smallish end of things, but interesting nonetheless), the stable lifetime is about 10 billion years (which we're about halfway through now). So, you know that if you see Solar mass stars more than about 10 billion light years away, they probably don't exist anymore. But that's pretty far away-- at a redshift of about 0.8 for a Hubble constant = 75 km/s/Mpc, and 10^10(ltyr)/3.26(pc/ltyr)= 3000 Mpc. It's out in the superclusters of galaxies!

But--the most massive stars are about 40 times the mass of the Sun. So they put out a lot more power, and die a lot quicker; in less than a couple of million years only. Well, a couple of million light years isn't very far now. It's only about 600 kpc-- just about the distance to the nearest galaxy, M31 (Andromeda).

The most massive stars are the most luminous, so those are what we tend to see when we look at galaxies other than our own. Bright lights are easier to see from far away than dim ones, right? Our quick calculations have shown us that even when we look at the nearest galaxies to our own, we are likely seeing them very differently from how they would look "now" in their own reference frame. I hope that answers your question. I'm sorry it took so long to reply, but I was out sick for a few days.

Answer 10

Yep.

When you look at the sun, you're seeing where it was 8 minutes ago.

When you look at stars, some of the light is thousands of years old. You're seeing the position of that star where it was a thousand years ago.

If you use the Hubble, you can see stars billions of years old.

Trippy, eh?