Speed of Light

Originally posted by agryson
Oh, in that case, the answer is that you look like a pancake flying through space. But at least you now know how to make space pancakes, right?

Cool, thanks 🙂

My pleasure. Pub physics is an important vocation. Did you know that if you have several dry beermats on a dry table, it is possible to stack them in such a way that the top beermat is over the edge of the table? Practice at home before you go, or be drunk, that's always a handy excuse.

Originally posted by adam warlock
Ever heard of tachyons? Superluminal motion isn't prohibited in general reltivity. Only bodies that start with v

All well and good but I think the theory gods have ruled them out.

Originally posted by agryson
My pleasure. Pub physics is an important vocation. Did you know that if you have several dry beermats on a dry table, it is possible to stack them in such a way that the top beermat is over the edge of the table? Practice at home before you go, or be drunk, that's always a handy excuse.

I shall have a go at that next time I go to the pub. Another good pub trick that can win you free drink is bet someone that the circumferance of a pint glass is longer than its height. No one will believe you, but it is! I guess you will probably know that already.

Originally posted by torchmoon
Lets say you can travel faster than the speed of light. If you travelled a certain distance stopped and turned round. What would you see? Would you see yourself going away from you or coming towards you?

Think of a quick turning on and off of a laser beam. So you turn on the laser for say, one nanosecond. thats a piece of the light beam that would be about 300 MM thick. So you can simulate what you are talking about by going sublight speed, say going to the moon, then setting up a com circuit where, because there is about a 2 second delay of light going from earth to moon, then you send a signal and they respond by sending out that 1 nanosecond flash. Think about it.
You are at position B, the light comes from position A, when you send the signal to tell the dude on earth to switch on the beam, you have to wait say 3 or 4 seconds at least before you see the laser flash.
So think about your hypothetical faster than light trip. The beam representing you is back towards where you left. So you go faster than light and say you outpace the beam by 10 seconds, turn around and look back, its exactly the same situation as my example on the moon.
You see NOTHING, because the light representing where you were has not reached you yet. 10 seconds later the light catches up to you and you see yourself or your vehicle. Capesh?

Originally posted by sonhouse
Think of a quick turning on and off of a laser beam. So you turn on the laser for say, one nanosecond. thats a piece of the light beam that would be about 300 MM thick. So you can simulate what you are talking about by going sublight speed, say going to the moon, then setting up a com circuit where, because there is about a 2 second delay of light going fro ...[text shortened]... yet. 10 seconds later the light catches up to you and you see yourself or your vehicle. Capesh?

Say you pass points A and B to reach point C. If you turn round at C wouldn't the light from B reach you first, and then the light from point A second? So wouldn't this appear as if you were travelling backwards?

Originally posted by sonhouse
Think of a quick turning on and off of a laser beam. So you turn on the laser for say, one nanosecond. thats a piece of the light beam that would be about 300 MM thick. So you can simulate what you are talking about by going sublight speed, say going to the moon, then setting up a com circuit where, because there is about a 2 second delay of light going fro ...[text shortened]... yet. 10 seconds later the light catches up to you and you see yourself or your vehicle. Capesh?

It's called the Achilles paradox.

A tortoise has a rocket pack strapped to its back, and Achilles lets the turtle have a 5 second headstart. Well, as long as that turtle is moving at a speed at least 90 % of Achilles speed and continues to accelerate, Achilles can spend all the time in the world trying to catch up to that turtle, but he never can because the turtle is constantly accelerating. As he gets closer and closer to the turtle, the more time will elapse. Say AChilles was 50 yards away but the turtle still moves ahead at 90% of his speed and continues accelerating. As Achilles closes the distance, years turn into decades, decades turn to centuries, and centuries turn into millenia. But Achilles will never overtake the turtle.

Now wherever I said "Achilles", replace with "light".
Wherever I said "turtle" or "tortoise", replace with "spaceship"

And you don't even have to be moving at superluminous speeds. as long as you have a head start on a beam of light, say a laser beam for instance. If you look behind you as you go somewhat near but just under the speed of light (say 95 % of c), you would look behind you and see an accelerational black hole.

Originally posted by sonhouse
Think of a quick turning on and off of a laser beam. So you turn on the laser for say, one nanosecond. thats a piece of the light beam that would be about 300 MM thick. So you can simulate what you are talking about by going sublight speed, say going to the moon, then setting up a com circuit where, because there is about a 2 second delay of light going fro ...[text shortened]... yet. 10 seconds later the light catches up to you and you see yourself or your vehicle. Capesh?

But when the light catches up to you, you see it coming at you all packed together hence the pancake effect. Of course, you might have to wait a while, but you would see something.
As for the light from b reaching you before a, the light from a has a headstart (see achilles) so a and b should reach you at pretty much the same time.

Originally posted by EinsteinMind
It's called the Achilles paradox.

A tortoise has a rocket pack strapped to its back, and Achilles lets the turtle have a 5 second headstart. Well, as long as that turtle is moving at a speed at least 90 % of Achilles speed and continues to accelerate, Achilles can spend all the time in the world trying to catch up to that turtle, but he never can be ...[text shortened]... ght (say 95 % of c), you would look behind you and see an accelerational black hole.

Well with Einsteins mind you should know better than that🙂
Why do you think you will see ANYTHING before the light reaches your eyes? If it's totally dark in the direction the light is coming from when the light gets to you the only dif you will see is the light not being at the right wavelength, you will see a doppler shifted version. But the light will be perceived by you as coming in at C anyway, because your time frame will be slowed down by relativistic effects since you are at 0.95C. You can't make any trickery with light. Einstein showed that.

Originally posted by torchmoon
I'm female not a guy (sounds of groans and oh that explains it heard), and kind of wish i never asked. I'm not big on physics as you all now know! I don't understand a word of what you all have said. It was supposed to be a fun question based on pub talk with my mates, sorry guys 😳

AWWW bless aren't you just the sweetest but seriously ladies' fuzzy little brains cannot cope with physics.

Originally posted by demonseed
AWWW bless aren't you just the sweetest but seriously ladies' fuzzy little brains cannot cope with physics.

I know, that's why I'm a microbiologist. Any time you want to know anything about food poisoning organisms, I'm your girl! 🙂

Originally posted by adam warlock
You could just answer the question the guy posted in the frame of reference of a tachyon then.

If I could answer his question, I would be a candidate for the Nobel Prize in physics.

No one knows yet if there exist any of these ghostly particles or if they just appear in mathematical formulae. No one has yet observed them, and no one knows how to observe them if possible.

The question is Newtonian and not Einsteinian. That means that one should avoid the relativistic effects to answer the question. This is not possible.

No one knows how the universe works in a above light velocities, even when you take the mass' complex component. Why do then any one think it is possible to answer the question?

the question is un-answerable and should be treated this way. this is not the Spirituality Forum where religion is taken into account.

Originally posted by torchmoon
I know, that's why I'm a microbiologist. Any time you want to know anything about food poisoning organisms, I'm your girl! 🙂

You would have had a good life in ancient Rome, eh! Hi, haven't had the pleasure of meeting you yet. If you are into music you could take a look at my myspace account, give a listen, donjenningsguitar.
Just to show you some of us are into other things than just chess🙂

Originally posted by FabianFnas
If I could answer his question, I would be a candidate for the Nobel Prize in physics.

No one knows yet if there exist any of these ghostly particles or if they just appear in mathematical formulae. No one has yet observed them, and no one knows how to observe them if possible.

The question is Newtonian and not Einsteinian. That means that one shoul ...[text shortened]... d be treated this way. this is not the Spirituality Forum where religion is taken into account.

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html

Read on. A lot of question about tachyons and how they see the universe were answered long ago and nobody received a Nobel Prize for it.

Originally posted by sonhouse
All well and good but I think the theory gods have ruled them out.

no they haven't. To this days a lot of articles are being written. I even once a book on them on the Library of my work+lace. They are not part of my field of work but I know that a lot of bright guys and girls work on them. If you want you can go http://arxiv.org/ and look for tachyons on it and read some articles to see that they are not ruled out. Yet that is.