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Gwnewch y pethau bychain

Boom-de-ah-da, boom-de-ah-da

Someone once said, “Not only is the universe stranger than we imagine, it is stranger than we can imagine.” While this is almost certainly true, the universe is awesome in its vast complexity, and the more we understand of it, the more amazing and mysterious it is.

So, on that note, here’s some fun stuff from the world of science.

First up, from camwyn, an animated GIF file that illustrates the relative sizes of celestial bodies, starting with the Earth and moving outward. As she notes:

Turns out that when you are conscious of the size of the largest known astronomical object in existence- VY Canis Majoris, a star so huge that it literally takes eight days for light to get from one side to the other- you have a hard time taking “But you ruined my view!” as quite so relevant to the greater scheme of things.

If that wasn’t enough to confirm that we're all really puny , epi_lj points me to an article in New Scientist magazine which suggests that it’s entirely possible that the entire universe is, in fact, a giant hologram:

For many months, the GEO600 team-members had been scratching their heads over inexplicable noise that is plaguing their giant detector. Then, out of the blue, a researcher approached them with an explanation. In fact, he had even predicted the noise before he knew they were detecting it. According to Craig Hogan, a physicist at the Fermilab particle physics lab in Batavia, Illinois, GEO600 has stumbled upon the fundamental limit of space-time – the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into “grains”, just as a newspaper photograph dissolves into dots as you zoom in. “It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time,” says Hogan.

If this doesn’t blow your socks off, then Hogan, who has just been appointed director of Fermilab’s Center for Particle Astrophysics, has an even bigger shock in store: “If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram.”

The best part about this story is that it was discovered more or less by accident. Issac Asimov once said that the most exciting words in science were not “Eureka! I have it!”, but “Hmmmm. That’s funny.”:

So would they be able to detect a holographic projection of grainy space-time? Of the five gravitational wave detectors around the world, Hogan realised that the Anglo-German GEO600 experiment ought to be the most sensitive to what he had in mind. He predicted that if the experiment’s beam splitter is buffeted by the quantum convulsions of space-time, this will show up in its measurements (Physical Review D, vol 77, p 104031). “This random jitter would cause noise in the laser light signal,” says Hogan.

In June he sent his prediction to the GEO600 team. “Incredibly, I discovered that the experiment was picking up unexpected noise,” says Hogan. GEO600’s principal investigator Karsten Danzmann of the Max Planck Institute for Gravitational Physics in Potsdam, Germany, and also the University of Hanover, admits that the excess noise, with frequencies of between 300 and 1500 hertz, had been bothering the team for a long time. He replied to Hogan and sent him a plot of the noise. “It looked exactly the same as my prediction,” says Hogan. “It was as if the beam splitter had an extra sideways jitter.”

I love the whole world. The world is just awesome.


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  1. a star so huge that it literally takes eight days for light to get from one side to the other
    I remember seeing a show that said that the light of the sun, because of the gravity well, actually took thousands (or hundreds of thousands) of years to get out (subjective time) … but I know what the article means 🙂

  2. A few puny facts

    Wikipedia and Wisegeek both have the radius of VY Canis Majoris as 9 AU. Since one AU is 8 light-minutes, that gives us a radius of 144 light-minutes, or not quite 2.5 light-hours.

    Just to complicate things further, that’s c, the speed of light in a vacuum. The speed of light in a star is another matter entirely. I don’t recall all the physics, but the basic idea is that it’s dense enough in there that photons bounce off things, constantly. I saw an estimate for the time it would take a photon generated by fusion at the center of the sun to reach Earth: 10 million years. The density of a hypergiant might be significantly less, but the distance to be travelled is a lot greater.

    (The Wikipedia article gives the time it would take light to circle the star, which avoids that problem, but how do you curve the light? Light-minutes, or light-years, are a useful distance measurement, but it’s sometimes best not to take them too literally.)

  3. Actually the most exciting phrase in science is “Oh shit”. However “Hmmm. That’s funny” is vastly more productive.

  4. a star so huge that it literally takes eight days for light to get from one side to the other

    As others have noted, this is not correct, at least in the expected interpretation.

    Toward the large end for the size estimates, the star is some 3x10^12 meters across. In a vacuum, light travels at 3x10^8 meters per second. Thus it takes light approximately 10,000 seconds (~2 hours 45 minutes) to travel across that sort of distance in a vacuum.

    The wikipedia article notes that it’d take light about eight hours to go around the star.

    It takes a very long time for light (or any energy) generated within a star to get out -- the mean free flight path for a photon (the distance the photon can go before hitting something) in the interior of a star is very short.

    • Yeah. Of course, even this small error in fact (which was from a quote) doesn’t actually make the body less awesome — 2.5 hours is a incredibly long time in terms of light travelling.

      The fundamental point of the entire post still stands though: The universe is a wicked cool place.

  5. the ‘stranger than we can imagine’ line was from haldane, though it’s been attributed to eddington too.


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