Friday, February 06, 2009

Our Universe May be a Giant Hologram

I'm going to have to get back to reading The Road To Reality to understand this... Our world may be a giant hologram. The GEO600 is a gravitational wave detector. It splits a laser beam and precisely measures a distance. If a gravity wave passes through it, it would stretch space-time and change the measurement. It turns out that there's some noise in the measurements they can't explain. Physicist Craig Hogan independently came up with a theory that would predict noise in the GEO600 contacted them and told they were seeing similar noise.

As best as I can understand it goes like this. Based on theories about black holes and extended to the universe itself, the holographic principle says that all the information about the contents of a volume are encoded in bits on the (2D) surface of that volume. The name stems from a hologram which in 2D encodes information to show a 3D image. The theories have been that the information of the universe is encoded at tiny Planck length scales on the boundary of space-time (just go with it :). Planck scale stuff is too small for us to ever measure, but Hogan's idea was that if the info on the surface exactly described the volume, then the volume must be at larger scales, scales we could detect. This would make the universe a "grainy hologram". His idea was that we could detect quantum fluctuations of the tiny 2D surface by looking at their effects in the larger 3D volume. Essentially the the universe would be blurry and the GEO600 would be able to detect that.

If all this proves out, it would be a huge discovery about the nature of the universe. And it would have been found by noise in an instrument designed to measure something else. It's far too early to say history is repeating itself, but such things have happened before.

In 1964 Arno Penzias and Robert Woodrow Wilson had built a radio telescope and it was picking up static that they couldn't identify. This turned out to be the first detection of the cosmic microwave background radiation (CMB). About 400,000 years after the Big Bang, when the early dense hot universe cooled from a plasma to allow electrons and protons to combine into stable hydrogen atoms, it turned transparent (and I guess into a gas). The CMB is the left over photons that were no longer being absorbed by the plasma and have since become less energetic. Penzias and Wilson won the 1978 Nobel Prize in Physics for detecting this antenna static (and not ignoring it).

(I'm really just trying to follow articles written for the laymen here. If anyone can correct me I'd be appreciative.)

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