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Fraser
2008-Jan-15, 02:50 AM
Thanks to GLAST, Astronomy Cast is now able to provide equipment to send to high school teachers who want to Pamela and Fraser to do a special questions show just for their class. We will be making this shows available on the feed on days other than Monday (that's still reserved for your regularly scheduled Astronomy Cast). This is the first one available and comes with questions from Farmersburg School.http://feeds.feedburner.com/~r/astronomycast/~4/212774482

More... (http://feeds.feedburner.com/~r/astronomycast/~3/212774482/)

NHR+
2008-Jan-15, 03:22 PM
I already wrote this elsewhere, but I'll copy it here, too:

In the Farmersburg School Questions Show, I just heard Fraser say, that if you go fast enough you'll turn into a black hole. Is that really so? I remember reading somewhere before, that speed does NOT really increase the mass of a moving body. Momentum and kinetic energy, yes, but NOT the mass. And that the whole concept of "relativistic mass" is just confusing and not really needed.

I happened to find a couple of links that say just this:

http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/black_fast.html
http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html

Are these just plain old ** then? :confused:

Steve Limpus
2008-Jan-15, 07:12 PM
Are these just plain old ** then? :confused:

nope - I would say you're dead right - the notion that (invariant) mass increases at relativistic speeds and that relativistic particles should form blackholes is mistaken, or at least oversimplified.

Great links - I'd not heard of the issue before.

Buck Rogers would be pleased. Turning your spaceship into a black hole would sure ruin your day, not to mention your federal funding!

Steve Limpus
2008-Jan-15, 07:22 PM
nope - I would say you're dead right - the notion that (invariant) mass increases at relativistic speeds and that relativistic particles should form blackholes is mistaken, or at least oversimplified.

Great links - I'd not heard of the issue before.

Buck Rogers would be pleased. Turning your spaceship into a black hole would sure ruin your day, not to mention your federal funding!

... I should say too: with all due respect to Fraser and the team. I haven't had a chance to listen to the show yet so I'm not aware of the context of Fraser's comment... and I ain't no expert! At the very least it stimulates thought about relativity. It did for me anyway.

Steve Limpus
2008-Jan-15, 07:44 PM
Another thought... the people at CERN talk about creating tiny black holes at the LHC.

Does anyone know if this is a similar concept or completely different? If the CERN guys say they can make black holes I tend to believe them, but I assume that relativistic motion of particles is not the mechanism they're referring to?

clint
2008-Jan-17, 01:26 AM
Another thought... the people at CERN talk about creating tiny black holes at the LHC.

Does anyone know if this is a similar concept or completely different? If the CERN guys say they can make black holes I tend to believe them, but I assume that relativistic motion of particles is not the mechanism they're referring to?

Probably not, since they do not get anywhere near light speed
(on the show, a current max. speed of 10% of light speed was mentioned)

Steve Limpus
2008-Jan-17, 03:50 AM
This seems to be a pretty good take on it:


"Some current theories suggest that gravity is so much weaker than the other forces not because it is intrinsically weak, but because gravity is allowed to spread out its lines of force into several extra dimensions, while the other three forces are confined to the 3+1 dimensional "brane" that we perceive as our universe. The implication of this idea is that at small distances (less than a millimeter) and/or high energies (more than 1 TeV) gravity may become quite a strong force... The implication of these ideas for the LHC is that the machine may be able to reach collision energies at which gravity becomes a very strong force and small black holes are produced in the collision."

http://www.analogsf.com/0305/altview.shtml

So not as a consequence of relativistic motion, rather a possible outcome of 1 TeV particle collisions and the possible extra-dimensional properties of gravity.

squid
2008-Jan-21, 12:27 PM
Would fast-moving particles create black holes in the sense of gravity wells, or would it be more of a low-pressure system vacuum? Objects in motion do create low pressure systems (Bernoule effect), so it seems to me that if something was moving fast enough (faster than the speed of light, say) it would be able to suck things toward it using pressure instead of gravity.