The time it takes light to reach Earth

Ok, here is what will probably be considered a stupid question but there is something Ive been wondering.
When we see light from an object in the Universe, it has already been traveling for millions of years so by the time it gets here, the object that created the light has moved vast distances through space or is not there anymore at all. I understand all that, I was just laying some ground work.
Something I dont understand is since the object that created the light is constantly moving and we are constantly moving then why is it that we still only see a tiny spot of light?
What would make more sense to me but would look pretty strange, is if the objects the came from a deeper part of space looked more like what it looks like when a camera takes an image and leaves the shutter open for a long period of time, which arcs the light across the night sky.
The light is constantly being emitted from the object at precisely the same speed but the object is constantly in motion as are we.
Im sure there is an explanation but it is probably one that will not make sense to me. I started to say "I know this isnt rocket science" but I guess it really is..

Now why doesn't it create the kind of streaking you demand? Well, the answer is really very simple. The camera doesn't update it's film constantly which is what the eye does.
When something hits the film or digiback the light gets stored and remain where the film or digi has been exposed to it.
Since light rules over darkness, streaking will occur.

You eye is constantly moving on to the next frame if you will thus avoiding streaks.

My god... life would be horrible if our eyes didn't update xD


There's probably some formula which dictates how fast something must go before it appears to streak. Along with the distance between you and the object.
Ofcourse it would also help if your eyes didn't film with 24/25 images pr. sec. (or is it something else?)

[edit on 8/8/07 by flice]

I'm not an expert on this at all, but I'm guessing the reason is this. If the object is very far away it could move vast distances to the left or right and it would hardly seem to move to us due to the distance between ourselves and the light source. The amount that the light moves will depend on how far away the object is, how big it is and how far the object moved. Hope that helps in some way.

Originally posted by flice
Now why doesn't it create the kind of streaking you demand? Well, the answer is really very simple. The camera doesn't update it's film constantly which is what the eye does.
When something hits the film or digiback the light gets stored and remain where the film or digi has been exposed to it.
Since light rules over darkness, streaking will occur.

I was just using that as an example, i know how cameras work vs the way our brain converts images.

It would just make sense to me that as dynamic as our universe is, billions and billions of Stars and other objects constantly throwing off light and constantly on the move that there would be more of a sort of streaking or maybe a better word is ARCING effect in the light that we see.
After all, light is even able to be bent around large objects gravitational fields, or so they claim.

but hey, thanks for the replies anyway

To the OP...

For the same reason when we watch a moving car, we don't see it as a blurred car, we see it clearly. The distance away is irrelevant.

Originally posted by Kr0n0s

Im sure there is an explanation but it is probably one that will not make sense to me. I started to say "I know this isnt rocket science" but I guess it really is..

Actually Kr0n0s, the technology hasn't been developed yet that can come close to the incredible workings of the human eye. The subject used to be one of the many heated exchanges going on in FPS multi-player games such as Quake.

The postulate that we can only see 30 fps comes from a misinterpretation first documented when television was in it's infancy. At a time when shutter speeds were slow and 8 millimeter film was exhibiting that familiar flipping or stutter.

As time and technology progressed FPS like you see today in games can be much faster without seeing any blur. Nothing can focus and assimilate images in as many brilliant colors reflected off objects as the human eye.

Eagles having more rods then cones can see great distance but the trade off is what humans have as the best balance or biggest bang for the biological buck.

Astigmatism notwithstanding you can turn your head as fast as you can and see everything go by. It may bee blurred but that is the cleverness in our human design.

The alternative would be like watching a lag cheater in games. The other awesome feature we take for granted as merely a cosmic coincidence of Darwinian happenstance, is while you are looking at your monitor just turn your head and look at the television.

Notice the immediate adjustment in focus no matter how far away 20-20 sight will see it. Actually it happens so fast you can't notice it. it is instantaneous. The technology is what was limiting us from seeing past 30 fps and was interpreted as our own physical limitation.

We now know that the speed of sight is considerably faster. Until the technology of our finite understanding catches up with whatever the enigmatic phenomena that sparked life into us or that primordial soup from whence we came,,

It is anyone's guess.


-=[conspiriology]=-










[edit on 22-8-2007 by Conspiriology]

reply to post by Kr0n0s




Great video on speed of light travel, gives perspective


mod edit to fix video link
We Now Have YouTube and Google Video BBcode and ATS!

[edit on 24-8-2007 by sanctum]

reply to post by Kr0n0s


Though the speed of light in the vacuum remains constant, the frequency does change as we move in relation to the source. If we're moving away, it gets shifted to the red end of the spectrum, blue if we approach it. It's called the doppler effect. You can find out more about it here.

Hope this helps better your understanding of light

By the way, if I'm not mistaken, it takes light from the Sun about 8 minutes to reach Earth from the moment it is released off of the the surface.