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Author Topic: Could we "surf" on gravitational waves?  (Read 3979 times)

Offline JPC

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Could we "surf" on gravitational waves?
« on: 06/02/2011 20:30:03 »
Jeremy Cox asked the Naked Scientists:
   
Hi Chris, and all the other wonderful Naked Scientists

Thank you for the help with my recent question (positronium). It didn't quite answer the question I was after, but further reading (using information from the show) allowed me to realise a rather large oversight on my part. I think I will be able to sort out my confusion.

Liking the show, I listen to a podcast probably every day. Often you seem to include nationality, for that purpose I am in the last year (12) of high school in Australia. Sadly what I'm wondering right now does not relate to leprosy (next show), theres no harm in asking questions though.

Regarding gravitational waves, from my understanding, they are a compression and stretching of space, much like sound waves in air.

Would it be possible to go cosmic surfing on these waves, traveling at 0.5c in the compressed portion of space, if the space were compressed to 1/2 it's normal length in the gravitational wave?

-Such a transportation system would not need constant tweaking to keep in the right spot of the wave, the spaceship would move forward or backward through the wave until it's speed/c was equal to (compressed space length)/(normal space length)... I think?

-You would need some way of reliably producing gravitational waves. I am currently not sure what the scale of gravitational space compression looks like. Wikipedia tells me: " Gravitational waves passing through the Earth are many billion times weaker than this" in relation to waves that approximately halve the length of space.

Once again thanks in advance for any answers provided. Can't wait for the next show.

Keep on making this great show, you're doing a great job!
Jeremy Cox

What do you think?
« Last Edit: 06/02/2011 20:30:03 by _system »


 

Online yor_on

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« Reply #1 on: 06/02/2011 20:56:22 »
Sweet idea but you should be 'compressed' too, shouldn't you?
==

I know I have a good reference somewhere to this concept. I'll see if I can find it.
But assume that we somehow could use a gravity wave to become a 'standing wave'?
Equally compressed in every point, that should become a effective time dilation relative the rest of the universe. You wouldn't go anywhere specific, any faster though, except in time. :)
==

Here you got it :)
« Last Edit: 06/02/2011 21:20:50 by yor_on »
 

Offline imatfaal

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« Reply #2 on: 07/02/2011 12:05:25 »
Jeremy - agreed "sweet idea". 

My initial reaction would be that you require a surface to surf on, when you are swimming the wave just causes you to bob up and down; a surfboard allows you to continually "fall down" the leading slope of the wave.  There is no surface within spacetime for the gravitational wave surfer to ride on.  But I think you anticipated this by referring to sound waves; this would lead to another question - can you surf on a longitudinal compression wave like sound?  I would have thought you would just waft backwards and forwards unless you can find a way to get pushed forward but not sucked back.
 

Offline granpa

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« Reply #3 on: 07/02/2011 13:32:16 »
 

Online yor_on

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« Reply #4 on: 07/02/2011 20:28:20 »
Yep, but the Alcubierre drive is not gravity. It 'uses it' but as gravity always will move at the 'speed of light in a vacuum' according to main stream descriptions, it's not really gravity anymore.

"In general relativity, one often first specifies a plausible distribution of matter and energy, and then finds the geometry of the spacetime associated with it; but it is also possible to run the Einstein field equations in the other direction, first specifying a metric and then finding the energy-momentum tensor associated with it, and this is what Alcubierre did in building his metric.

This practice means that the solution can violate various energy conditions and require exotic matter. The need for exotic matter leads to questions about whether it is actually possible to find a way to distribute the matter in an initial spacetime which lacks a "warp bubble" in such a way that the bubble will be created at a later time. Yet another problem is that, according to Serguei Krasnikov, it would be impossible to generate the bubble without being able to force the exotic matter to move at locally FTL speeds, which would require the existence of tachyons. Some methods have been suggested which would avoid the problem of tachyonic motion, but would probably generate a naked singularity at the front of the bubble."

And a singularity is a 'breakdown' of SpaceTime in where "there might be thygers" and where our concept of 'speed' loses all meaning.
==

In fact its like 'tunneling', but here the 'tunneling is you being stationary inside a 'singularity', with the singularity 'moving' inside our SpaceTime. A highly original concept as it assume that a 'singularity' still exist inside the dimensions it can't be.
« Last Edit: 07/02/2011 20:33:26 by yor_on »
 

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