Are there any physisists on the forum?

[twentysix by twentyfive]

This one :- http://www.gravityfromthegroundup.org/

 

[02GF74]

ok, whilst we on this subject.

Let's say I am in my 2CV and have fitted twin turbos that allow me to drive at the speed of light.

what would I see through the side windows and rear view mirror?

i.e. am I travelling so fast that the light from object usually visiible in the side windows and rear camnnot reac me, hence the windows will be black?

 

[twentysix by twentyfive]

ok, whilst we on this subject.

Let's say I am in my 2CV and have fitted twin turbos that allow me to drive at the speed of light.

what would I see through the side windows and rear view mirror?

i.e. am I travelling so fast that the light from object usually visiible in the side windows and rear camnnot reac me, hence the windows will be black?

Err No. The stuff in front would look blue and the stuff from behind would look red. The stuff from the side would still look white. Over the 360 degrees you will cycle thro blue, white, red, white and back to blue with various shades between these extremes. Objects to the side will look rather distorted and you will be able to "see round corners". All to do with "Length Contraction" and "Time Dilation".

 

[Night Train]

ok, whilst we on this subject.

Let's say I am in my 2CV and have fitted twin turbos that allow me to drive at the speed of light.

what would I see through the side windows and rear view mirror?

i.e. am I travelling so fast that the light from object usually visiible in the side windows and rear camnnot reac me, hence the windows will be black?

What you would see in the rear view mirror is the rear view slowing down as you approach the speed of light and then stopping, frozen in time as you travel at the speed of light.

From the side windows you will see the landscape compressing. So if there was a row of trees then you will see new trees from ahead approaching the front edge of the side window but the trees you have passed will still be visible at teh back edge of the window so they all squash up to fit in.

 

[colly]

But as the particles are travelling in opposite directions on a collision course their relative speed is 2x speed of light. If one beam was fired at 90%. the impact would only have half of the energy.

Ah yes, BUT, and possibly this is the nub of the issue.

Will their velocity relative to one another still be less than the speed of light?

 

[Night Train]

It is perfectly possible to have a speed greater then c, 1,000,000,000 miles per second for instance is a lot greater then c.
However, it is a different matter to have a particle or wave traveling greater then c.

Two beams of light traveling towards each other would have a closing speed of 2c but each beam would still only be traveling at c.

I suppose you could say that in some circumstances an assumption could travel faster then c.
I assume that a particular star, 1000 light years away, has just gone nova.
In a thousand years we will know if my assumption was correct and a nova occured. You could then say that my assumption of the event was faster then our knowledge and awareness of it which only travelled at c.

This then becomes more complicated.
If my assumption was correct then I must have known at the same time as the event. That would mean that the moment in time must have been the same and so time must travel instantaneously, and so faster then c.

Alternatively you could say that the time of the event was 1000 years before it became knowledge. That would mean that my assumption time travelled backwards in time 1000 years.
General relativity (I think) says that anything that travels faster then c will experience time traveling backwards. So my assumption could have happened faster then c and travelled back in time 1000 years from the knowledge of it to now.

 

[mangaman]

Blimey - it makes my head hurts all of this cleverness.

Why can't someone just sit under an apple tree in a Newtonian way until one falls on his head. Surely we'd have the answer then?

 

[Night Train]

Blimey - it makes my head hurts all of this cleverness.

Why can't someone just sit under an apple tree in a Newtonian way until one falls on his head. Surely we'd have the answer then?

You mean random falling photons?

I suppose if you had enough people and dropped a load of photons on their heads you could tell by the scatter pattern of photons on the ground that they appeared to be waves and not particles.

 

[mangaman]

You mean random falling photons?

I suppose if you had enough people and dropped a load of photons on their heads you could tell by the scatter pattern of photons on the ground that they appeared to be waves and not particles.

Now you're just making it worse NT

Maybe I should go to bed!

 

[Night Train]

Now you're just making it worse NT

Maybe I should go to bed!

Moff to bed too.

 

[Yellow Fang]

Ah yes, BUT, and possibly this is the nub of the issue.

Will their velocity relative to one another still be less than the speed of light?

Yes, suppose you were Luke Skywalker flying at 99% light speed your X-Wing fighter and you fire your laser guns at Darth Vader coming back at you in his TIE fighter. Because time slows down the nearer to light speed you get, your laser blasts still look like they're going at full speed. When Darth Vader fires back at you, it looks like his laser blasts are coming at you at full light speed.

I could be wrong here, but due to you traveling at 99% light speed, you should be perceiving your laser blasts as traveling at 1% of light speed. Instead, you perceive them to be traveling at full light speed, which means that time for you has slowed down by 100 times. If time has slowed down for you, then you perceive Darth Vader coming towards you as being 100 times slower.

Back down on Tatooine, it seems like you and Darth Vader are closing in on each other while your laser blasts gradually edge ahead of your spacecraft.

 

[Chrisc]

So c is the constant but t is elastic.
How does all this affect my poor lap times? The faster I travel the slower I get relative to the track...

 

[levad]

I think Bonnie Tyler sang about all this in "Faster than the speed of light"
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or was it "Faster than the speed of night"?

 

[Yellow Fang]

Yes, suppose you were Luke Skywalker flying at 99% light speed your X-Wing fighter and you fire your laser guns at Darth Vader coming back at you in his TIE fighter. Because time slows down the nearer to light speed you get, your laser blasts still look like they're going at full speed. When Darth Vader fires back at you, it looks like his laser blasts are coming at you at full light speed.

I could be wrong here, but due to you traveling at 99% light speed, you should be perceiving your laser blasts as traveling at 1% of light speed. Instead, you perceive them to be traveling at full light speed, which means that time for you has slowed down by 100 times. If time has slowed down for you, then you perceive Darth Vader coming towards you as being 100 times slower.

Back down on Tatooine, it seems like you and Darth Vader are closing in on each other while your laser blasts gradually edge ahead of your spacecraft.

I suspect I got some of this wrong. I'm pretty sure that to Luke Skywalker, it appears that his laser blasts are travelling at 186,000 miles per sec, and that Darth Vader's are coming towards him at 186,000 miles per sec. I'm pretty sure that means time has slowed down by 100 times for Luke. I'm not sure what speed he thinks Darth Vader is travelling. He probably still thinks he and Darth are flying at 184,140 miles per sec. A curious thing is that in the time the laser blast has distanced itself from Luke's X-Wing by 186,000 miles, Luke himself has travelled 18,414,000 miles in what appears to him to be one second, which would be impossible as it's nearly 100 times the speed of light. I think this explained by Luke's perception that space has become squashed up. When he looks out the side of his cockpit, it appears that Tatooine and its two suns are discus shaped.

 

[Tollers]

Ah yes, BUT, and possibly this is the nub of the issue.

Will their velocity relative to one another still be less than the speed of light?

No, Their velocity relative to 2 objects moving in opposite direction to each other will be 2 x speed of light