Very high frequency radiation makes dark matter visible

EurekAlert ^ | 12/14/06

[Maceman]

The pregalactic hydrogen has structures of all sizes which are the precursors of galaxies, and there are up to 1000 of these structures at different distances along every line of sight. A radio telescope can separate these because structures at different distances give signals at different observed wavelengths. Metcalf and White show that gravitational distortion of these structures would allow a radio telescope to produce high-resolution images of the cosmic mass distribution which are more than ten times sharper than the best that can be made using galaxy distortions. An object similar in mass to our own Milky Way could be detected all the way back to the time when the Universe was only 5% its present age. Such high-resolution imaging requires a extremely large telescope array, densely covering a region about 100 km across. This is 100 times the size planned for densely covered central part of LOFAR, and about 20 times bigger than densely covered core of the Square Kilometre Array (SKA) the biggest such facility currently under discussion. Such a giant telescope could map the entire gravitating mass distribution of the Universe, providing the ultimate comparison map for images produced by other telescopes which highlight only the tiny fraction of the mass which emits radiation they can detect.

Well, du-uh.

[unkus]

Yeah, uh, right.

[onedoug]

M-Theory re God.

[rjp2005]

Interesting, but way, way over my head. I read two sentences and my head is spinning.

[lowbridge]

Very high frequency radiation makes dark matter visible

Ah, more stuff we humans learned from that crashed spaceship in Roswell, NM in 1947. Finally the Pentagon has decided to release this info. ;-)

Oh, I'm gonna be intimidated and harassed by the mysterious Men in Black, I just know it.

[lowbridge]

The pregalactic hydrogen has structures of all sizes which are the precursors of galaxies, and there are up to 1000 of these structures at different distances along every line of sight. A radio telescope can separate these because structures at different distances give signals at different observed wavelengths. Metcalf and White show that gravitational distortion of these structures would allow a radio telescope to produce high-resolution images of the cosmic mass distribution which are more than ten times sharper than the best that can be made using galaxy distortions. An object similar in mass to our own Milky Way could be detected all the way back to the time when the Universe was only 5% its present age. Such high-resolution imaging requires a extremely large telescope array, densely covering a region about 100 km across. This is 100 times the size planned for densely covered central part of LOFAR, and about 20 times bigger than densely covered core of the Square Kilometre Array (SKA) the biggest such facility currently under discussion. Such a giant telescope could map the entire gravitating mass distribution of the Universe, providing the ultimate comparison map for images produced by other telescopes which highlight only the tiny fraction of the mass which emits radiation they can detect.

Can it turn on a tv?

[Lady Jag]

I didn't think it would work, but it does!

[OregonRancher]

Actually, when you think about it, it makes sense.

[Clioman]

Uncontrolled dark matter? Probably a Halliburton product. This, too, is obviously the fault of Chimpy Bushitler...

/s

[Robert A Cook PE]

Hmmmmn.

Somehow I'm distrustful of theories that "require" that 96% of the universe be not only invisible and not measurable, but that we "believe" this matter must exist because the "math is prettier" when 96 percent of the universe is "magically" created.

Yes, the math is simpler when dark matter can be used to explain bending and create a universe that will eventually close back on itself.

If Occam's razor holds, then the simplest theory requires that visible matter be explained. Not that a universe made of 96% "dark matter" and "dark energy" be created.

[LibWhacker]

Don't feel bad, you're not alone! I've read it several times and can't say I fully understand it.

[RightWhale]

Okay, gravitational lensing. Is the distribution of dark matter any different than real matter? Whatever matter is.

[LibWhacker]

Exactly, that's the question! It's amazing to me that the answer to so mundane a question as that could be so important for cosmologists. Yet apparently, it could tell us lots of new things about matter, dark matter, and the nature of the universe itself. It seems like THAT in itself ought to be telling us something.

[Radix]

A 100 kilometer diameter radio telescope could cost a few drachmas to construct.

It's been a long time since I took an astronomy course but I can't see the practicality of building a telescope that size.

Does the Earth's atmosphere effect radio in the same way that visual images are distorted?

Or did I misunderstand the reference?

[RightWhale]

There is no general agreement of what space is, or time, or matter. In physics class we had to answer up quite quickly and brightly of course. They don't allow the philosphy dept in the same building as the physics and engineering dept for good reason.

[LibWhacker]

Not sure if this is what you meant, but I'd hesitate to dismiss it as a purely philosophical question. For instance, the interaction between theorists and experimentalists has benefitted both many times over. Now, I don't know offhand if I'd want to spend $20 billion on a 100-km telescope... But I might be able to be convinced that it was desirable. :-)

[LibWhacker]

Hmmm... Gotta be careful here... I believe the atmosphere is transparent to most if not all radio wavelengths, ignoring the effects of lightning, etc. Anyone else know for sure?

[RightWhale]

A 100 km radio telescope could be built for $10. You need two antennas, any size, 100 km apart. They could be linked with anything, cell phones, for example. An old laptop would provide the software and data processing capability.

There have already been radio telescopes of 5000 km using off the shelf components to image the surface of Venus.

Not to say that a request for $20 billion is out of line, but it is extraordinary and will only populate Kant's 1755 nebular model with some more data.

[RadioAstronomer]

Nope.

http://en.wikipedia.org/wiki/Image:Atmospheric_electromagnetic_transmittance_or_opacity.jpg