Snakebyt

while looking at the other thread about the hubble telescope pics, i began to wonder somthing, and it has bugged me for a couple days now. I am not sure how much sense that will make to most people, but in my strange little mind....

While looking at some of the pics i noticed that they listed one of them was 4000 light years away from earth. Since there has to light for a picture, and visions are made from light. Would that mean that the picture that was taken was actually 4000 years old? Since it took the light 4000 lightyears to get to us for us to me able to take the pic?
Does this make sense? i know its a stupid subject, but it has peaked my intrest.

lordjeebus

Yes, you are correct.

If that blows your mind -- we have telescopic images of objects billions of light-years away.

Snakebyt

thats really weird.. how do we know that it is even still there? after all, 4000 years is a long ass time!!

lordjeebus

4000 years isn't very long for a star -- it's probably still there.

But there are many stars that we see in the sky that burnt out or exploded millions of years ago.

Also, if you look really deep into space, you can see things like quasars that existed in the early years of the universe, billions of years before the solar system (or our galaxy, for that matter) formed.

Snakebyt

i think that it is all beyond what my mind percieves. Just never thought it about all of it on a grand scale

VitaminH

Makes ya feel kinda small and insignificant, doesn't it?

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Neato

If I remember correctly, can't we "see into the past" seconds before the suposed big bang? Seconds after the universe was created?

Psivage

I heard that as well. Also I could of swear couple of times I will be out looking at star and poof they are gone.

supersix2

You are correct about being able to see the big bang. We are able to observe and analyze the microwave background radiation and to determine a lot about the universe's beginnings.
Also, there is a theory that if we know the exact position and velocity simultaneously of all particles in the universe we will be able to predict and see everything that has happened and everything that will happen. Because of the uncertaintity principle it is impossible to know the exact position and velocity of a given particle at the same time.

Fearless_Hyena

sure, i think it's wild that the star in question could blink out this instant and we would not know it for 4000 years!

lordjeebus

There's a simple explanation for that -- your eye has no rods at the center of vision, just cones. Cones are used to determine color, but are less sensitive to light than rods. Hence, a star can seem to vanish when you look at it directly.

joesmith

if the big bang exists as common theories dictate - we can't see into the past becasue time began as space began - so before teh big bang.. time didn't exist
(i know.. then your brain tried to ask - ok but then WHEN did time start) but you can't ask that either... you have to look at time more as a thing that you can move around inside of rather than an infinite road you travel down

thejoker130

Something to help you sleep at night.

It takes the light form the sun 8 minutes to reach earth, so if the sun exploded it would take the blast that long to get here.

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tecoyah

actually it would take the blast much longer than the light....a good example is the recent solar storm that disrupted some communications. We had over 30 hours warning before the effects got here.

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ObieX

Yea it may take the *light* 8 minutes to get here. But solar matter would take a bit longer, since it wouldn't be traveling at the speed of light. So you'll have some time to kiss your ass good-bye, if our sun were to explode, before you would be olbliterated. (although our sun is too small to explode.. it'll probably just burn itself out. Never know though!)

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thejoker130

All true. However, we probably would freeze to death before we got blown up by the blast now that I think of it.

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Tiser

Yes stars don't have this spontaneous desire to dissipate at all. Lots of warning, even thousands of years ahead.

Dilbert1234567

kind of makes you feel small and insignificant huh

well get used to it, we are.

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yellowgowild

I liked the part in "3001" where they said supernovas were industrial accidents.

geodaro

It would even be wierded if the star was located 4,000 light years into the future. Then that light wouldn't have been created yet for the picture and we wouldn't be able to see it at all! (I wonder what it's like 4,000 years from now?).

jwoody

Suppose there was a massive explosion in space, big enough to wipe out the entire galaxy, we would see it long before it's effects reached us and wiped us out.

So, theoretically, there would be a huge wave of light hurtling towards us and eventually passing over the planet with relatively minimal effect, probably blinding all who were foolish enough to stare, followed some time later (days, months even) by the blast which would be our eventual end.

Cool.

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skier

Yeah our sun won't "blow up" in an impressive display of supernova goodness, but when it does reach the end of it's life cycle (about 6 billion years from now) it will undergo several periods of contraction and expansion due to the lack of hydrogen (converted to helium)- there won't be enough fusion reactions to support the star's massive weight. The core collapses until the helium begins to burn into carbon, while the remaining hydrogen expands and burns itself quicker due to the increased surface area- the expansion of the star (into a red giant) will stop a few million kilometres from earth, turning it into a red molten ball. This outer sphere of hydrogen and helium disperses aroudn the solar system, leaving the core of carbon, a white dwarf.

So if we managed to live a few billion years, we'd die a horrible burning death, not a cold frozen one.

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glytch

I think I'd rather die a horrible burning death as you described, skier. At least it would probably be quicker (and much more fun to watch). Too bad none of us will be around to witness it.

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Akira

http://www.mkaku.org/ go there and read about this guys theories, his book really makes you think. This article here makes you think about stuf http://www.mkaku.org/articles/blackh...ormholes.shtml

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