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Why do we see light from stars that are millions of light years away?

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posted on Apr, 17 2012 @ 02:32 AM
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When I look at the stars at night the light seems continuous without any sudden blackouts. I don't understand why? (There is some minor fading in and out due to our planet's atmosphere, but that's not what I'm wondering about.)

Does that mean that the light emitted from a star has traveled uninterrupted for millions of years? Those are huge distances. The photons never hit any object on their long travel? It boggles my mind that space is really that empty.

Am I missing something? Given the speed of light and the time and distance of travel chances should be pretty good that "something" has temporarily blocked the light. Maybe just for a few seconds. It doesn't look that way when I watch the stars.




posted on Apr, 17 2012 @ 02:45 AM
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I think photons don't exactly travel in a straight path. It's said that light from the sun takes 7 minutes to reach Earth. That's true, but also it isn't. Something traveling at the speed of light will take seven minutes to travel the distance from Sun to Earth, but photons bounce around and zigzig. One photon may take thousands of years to reach Earth.

I believe the slit experiment is relevant here also. Light can be a wave or a particle so it can travel in funny ways.

Stars also emit a lot of light and energy, and they are very large. Perhaps you dont see them flicker for the same reason a cars headlights don't flicker when a bug flies in front of one.

However we do detect exoplanets by the slight drop in a stars luminosity when the planet passes in front, so in a way they do flicker, our eyes just aren't sensitive enough to detect it.
edit on 17-4-2012 by ZeroReady because: sp



posted on Apr, 17 2012 @ 02:48 AM
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reply to post by AllIsOne
 


Space isnt empty, it's booming with particles. Just not those that block light from passing trough.

Yet when you look at a star you will see it in a different position to where it actually is with most of them due to gravitational lenzing.

Actual mass that can physically absorb/block light is only 0.01% of the Universe (+/-
)



posted on Apr, 17 2012 @ 02:51 AM
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Originally posted by ZeroReady
I think photons don't exactly travel in a straight path.


While still in the sun their behaviour is irratic, as soon as they exit the corona it's a steady stream (i believe)



posted on Apr, 17 2012 @ 02:56 AM
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good observation...

they have been shining for millions of years so we can see it. If a star vanishes we won't see it happen. If a new star started to shine... we would not see it straight away. It would have to have been shining for a long time before we could see it.

I think that is amazing



posted on Apr, 17 2012 @ 03:01 AM
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Would you rather have a completely black sky?

Stop asking so many questions.




posted on Apr, 17 2012 @ 03:01 AM
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Originally posted by Thurisaz
good observation...

they have been shining for millions of years so we can see it. If a star vanishes we won't see it happen. If a new star started to shine... we would not see it straight away. It would have to have been shining for a long time before we could see it.

I think that is amazing




So if your close to the star that vanishes, you can see it vanish, but from far away you still see it?



posted on Apr, 17 2012 @ 03:04 AM
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It would take something at least the size of that star (perspectively speaking) to block all of it's light. There are things between us and the stars but they are generally not that big.

We actually use sensitive instruments to detect the dimming of a star's light (typically by only about 0.1 percent) when large objects pass in front of it. This is one of the modern day techniques for detecting planets orbiting those stars.


edit on 17-4-2012 by dainoyfb because: It needed clarification.



posted on Apr, 17 2012 @ 03:09 AM
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Originally posted by litterbaux
Would you rather have a completely black sky?

Stop asking so many questions.



I thought this is what a forum is for?

Ask, discuss, get answers...

Stop being a tool



posted on Apr, 17 2012 @ 03:11 AM
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reply to post by AllIsOne
 


What fry's my mind is some of these stars we see have burned out or exploded millions of years ago but we haven't seen this event yet because the light from them are just getting here....



posted on Apr, 17 2012 @ 03:15 AM
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reply to post by LDragonFire
 


It's hard to wrap your head around yeah. Now what's keeping that supernova from happening that's gonna give us a 2nd sun for a few days?
(we're overdue average wise)



posted on Apr, 17 2012 @ 03:17 AM
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Originally posted by dayve

So if your close to the star that vanishes, you can see it vanish, but from far away you still see it?


It depends how close you are to the star. If the sun blinked out right this second, you wouldn't know about it for 8.3 minutes. If a star 3.6ly away and vanished, we wouldn't know about it for 3.6 years.



posted on Apr, 17 2012 @ 04:41 AM
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reply to post by AllIsOne
 


And think of this, photon wise: There are so many photons emitted that the light (photons) from a star is constant whenever you look at it -- but also whereever you look at it. If you move an inch over it's an entire different area that the photons have to reach. And those too are a constant stream (it isn't even a stream as we envision it, as the amount of photons needed to keep up an image every moment of time is itself unimaginable). All in all, lots of photons.



posted on Apr, 17 2012 @ 07:59 AM
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reply to post by AllIsOne
 


The space is pretty empty. Just to give you an idea. The closest star to us is Proxima Centauri is 4.22 light years away. This is 39,900,000,000,000 km or 57,368,800 times the radius of the Sun. The distance between stars gets smaller the closer to the galactic center you get. But there is still plenty empty space in between.

Star light does fluctuate. This is how extra-solar planets are identified. It is just that the human eye is not sensitive enough to notice it.



posted on Apr, 17 2012 @ 08:18 AM
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Whats is truly amazing is that when we look at distant stars, we are looking back in time. At Light that was emmited from a star, millions of years ago, of course this depends on what star you are looking at, it could be less or more. For all we know, most of the distant stars could all be very different now, some gone in a Super Nova, some turned into Red Giants, and new ones being born changing the sky we adour forever.



posted on Apr, 17 2012 @ 09:33 AM
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I always wondered why the light these objects arent skewed or streaked.
Our planet is moving, our galaxy is moving, the star is moving and its galaxy is moving, you would think that after traveling such a long distance, by thr time its light gets here, it would be streaked across space.
*shrugs*



posted on Apr, 17 2012 @ 09:38 AM
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reply to post by AllIsOne
 


They are billions of years old and gigantic. Something super massive would have to pass by to block out that light.

You should scope out one of those star comparison size charts to see. It helps one understand why we can see these distant stars from so far away. The ones we see are usually much much bigger than our sun.
edit on 17-4-2012 by GogoVicMorrow because: (no reason given)



posted on Apr, 17 2012 @ 09:49 AM
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Amazing answers. I've learned something. Thank you all!



posted on Apr, 17 2012 @ 10:00 AM
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reply to post by AllIsOne
 

Great. Then here's another question. With so many stars in the universe, how come we see any dark patches at all? After all, the universe is thick with stars in every possible direction. We should be in the middle of a frying white-out, not darkness sprinkled with a few puny little lights. How come?

It's an old question, but it has an interesting answer.



posted on Apr, 17 2012 @ 10:00 AM
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its because your sight is faster than light i thought everyone knew that if you covered the sun up and instantly uncovered it it wouldnt take 7 minutes to see it how ever it may take 7 minutes to feel it
edit on 17-4-2012 by stealthmonkey because: (no reason given)




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