Question 2 Light Speed over 1 metre?

Question

So light travels at the speeds a few of you have given, thanks for that. So the fact is that we exist in present TIME but live in the PAST according to the speed of light. Everything we see is actually delayed by a fraction of time. Am I Right?

Answer 1

Correct. Granted, for any everyday purpose, the delay is so small as to be irrelevant. But that is the way things are.

BTW--that won't always be true--as humanity starts to move out into space, the speed-of-light limit will start changinghow we communicate. Example: Mars is (at best) over 3 "light-minutes" away. So if you're talking to a freind on tha tplaneddt via radio and ask a question, you'll have to wait 6-40 minutes for the answer (depending on where Mars is relative to Earth). So "conversations" in the usual sense will be impossible. That's one thing we'll have to start dealing with ina few decades.

Answer 2

Yes the speed of light is very fast and until proved other wise is believed to be a constant. (it does not change). Yes we live or dwell in the present (Now) and look at any object is seeing the object as it was when the light from it or reflected by it left it. On normal a day to day view, this makes little different to what we see but looking at the night sky, as has been said, we see stars which may be long since extinct. on the other hand, as you look at my answer, the information is probable being carried on a fibre optic, a cable which uses light pulses rather than electrons on an electrode (normal copper cable) to move the information to you. Why, because this information could be sent round the world at the speed of light. Think how many computer services we use which are linked into the WWW in some way all using fibre optic cable and you see we are very dependent on the speed of light every day for so many things.

Answer 3

In a sense you are correct: it takes an amount of time for light to reach the retinas of our eyes, and so by the time the eye detects the photons from something, that something has already occurred in the past.

But for most of the things in our lives, this 'delay' is so small it might not even be measurable with sensitive instruments.

There is a much larger delay between the detection of light by the retina and the time at which the brain realizes that a photon has reached the retina.

And then there is even more of a delay as the brain processes the information to generate the perception of an image.

And then there is an even longer delay as the brain organizes a response.

For example, you are shown a picture of a cow ...
Light from the picture reaches your retina in 3 X 10^-9 seconds or something.
Then it takes perhaps 0.3 seconds for that info to reach the brain,
And another 0.3 seconds to process the input,
And another 0.4 seconds to send out a response,
And so, 1.0 + 0.000000003 seconds later, you say "A cow!"

You can demonstrate this also by tapping your own knee to trigger the reflexive knee jerk: with your leg dangling loosely, hit the tendon at the bottom of your knee cap gently with the side of your hand. If you watch and feel closely, you will see your hand hit, and then see your leg move.

Another demonstration is if you accidentally burn your finger = you will jerk your hand back before you realize it has burned. This is because the spinal cord moves your hand away from the danger before the brain even gets and processes the information. Thus, your hand moves before you even perceive the trouble.

So, as you say, in a sense we are really living and reacting in the past, but much more because of the physics, chemistry, and biology of our brains, than because of the physics of the speed of light.

But in another sense, it really doesn't matter = everyone is equally delayed, and our brains compensate when necessary, or don't pay attention when it doesn't matter.

Answer 4

Yes, we see everything as it was when light left the surface of the object we are viewing. We do exist in the present time, now, you are using the wrong tense, it should be, we lived in the past. Nothing changes because of the delay in time when you see an object. When you watch a sunset, the sun is already below the horizon when you see it as just above the horizon because it takes 8.5 minutes for light from the sun to reach us. Nothing has changed because of this, it is still, now.

Answer 5

Yeah, but what if you're blind?

Reflected light from the moon takes more than a second to reach earth. The heat and light generated by the sun takes about 8 and a half minutes and light from the next nearest sun, Proxima Centauri, takes more than 4 years.

I recommend you never look at the the night sky because, if you're right, you would instantly travel so far back in time, the human race would not exist..

(Actually, that really is what happens.)

Answer 6

Yes your right-but it depends on how far you are away from what you wish to observe!.
To all intents and purposes all that goes on around us is in real time-we see it as it happens milliseconds later-due to the speed of light.
But if we observe our galaxy and the stars they are beyond our imaginable perception of distance-they are that far away that the light can take many,many years to reach our eyes-ie the stars we can see now could have in fact 'died' many years ago and the 'vision' has only just been received by us.
so we could dependent on the distance be seeing things in our distant past-which then asks the question does light degrade?.
If a light beam is sent out does it fade after a certain distance-does it fade or disappear??????.where does it end or begin..
Regards Richard U

Answer 7

Everything we see is delayed by the time it takes for our eyes to react to the light = a few 10's of picoseconds. Plus the time it takes for the image signal to travel on the optic nerve to the brain = a few hundred nanoseconds. Plus the time for the brain to form a mental image = again a few hundred nanoseconds. Call the total about 1000 nanoseconds.

Light travels about 300 meters in the same time.

Of course, that 1000 nanoseconds is just the beginning of a several millisecond process ( millions of nanoseconds) that it takes for your brain to recognize a "cow".

Answer 8

No, we live in the present. We see the past of the things we look at because it has taken time for light to get to us. We all live in our own personal 'present' and no two are the same.

Answer 9

Yes. We travel though time looking backwards. Everything we see is in the past.

Answer 10

Everything is relative. Distort the sense enough and you can make someone relive past memories, see and talk to cartoon characters, feel as if they are flying, and anything else that our minds can think of. Our brains are wonderful instruments of possibilities.