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Light, mirrors, gravity!

Posted 03-10-2008 by Francis Reddy

Yesterday’s Milwaukee Journal Sentinel ran a nice summary of efforts by the University of Wisconsin - Milwaukee to detect gravitational waves. The article focuses on NEMO, the $1.8 million, 1,560 CPU, Beowulf-class computing cluster built and operated by the school’s gravitational-wave group. (Ah, I love that kind of talk.)

NEMO was commissioned in 2006. Since then, it’s been chugging through data produced by the Laser Interferometer Gravitational Wave Observatories (LIGO) in Hanford, Washington, and Livingston, Louisiana. Here’s an informative cartoon of the setup.

These facilities bounce lasers back and forth to track length changes smaller than the diameter of a hydrogen atom. Such changes would occur when gravitational waves pass by and ripple through our local space-time. Relativity predicts such things, but so far, no one has detected them.

Scientists continually are improving the reach and sensitivity of these observatories. Sooner or later, they’ll detect signals from things like inspiraling pairs of neutron stars or black holes, core-collapse supernovae, and possibly even gravitational waves from the Big Bang.

You can participate, too. Since early 2005, LIGO data has been distributed to personal computers and processed using the Einstein@Home project’s nifty screensaver. This gives users eye candy in return for background use of their computers (more about it here).

Einstein@Home lets users “compete” as teams. I formed Team Astronomy as soon as the project went public. We now boast 69 members with computing credits, which are points awarded based on the amount and speed of data processing by each computer.

Team Astronomy now ranks in the top 45 in terms of recent average credits, but I think we can do better. Feel free to join us in search of gravitational waves. It may be the closest you’ll get to a Nobel prize.

Comments

  • Antitax said:

    What an agonizing wait! I know science can't get ahead of itself but sometimes discoveries come so late and so sparsely, we wonder if we'll be dead before the big questions are answered. Of course, no one will live forever to witness all there is to be found. But I wish more was discovered during my lifetime. Do many people suffer from the same impatience?

    March 13, 2008 6:25 AM
  • Francis Reddy said:

    It's easy to Google a fact. But there's an awful lot involved in acquiring such a fact in the first place.

    First, understand the situation well enough to figure out the right questions to ask. Then, determine the best ways to answer them. Next, decide where these questions rank among the many others scientists want answers to, and determine what fraction of a very limited pool of resources (human, technological, financial) you can afford to throw at them. Now, using those resources, leverage existing technology (cheaper) or invent new technology (costlier) to do the job.

    You may find you were asking the wrong questions. Or that you didn’t choose the best path for getting your answers.  

    To make matters more annoying, throwing all available resources at a problem isn’t the best solution. Science has a serendipitous side. Some discovery in, say, information theory or cryogenics or astrophysics may provide a theoretical or technological edge that makes a given problem much more tractable.

    Consider mapping the human genome. This was supposed to take 15 years. Additional resources made available as other countries signed onto the project, together with an innovative approach introduced in 1998, shaved almost 30 percent off this time.

    Here's another one: Up until the 1960s, rocket scientists thought exploration of the outer solar system would have to wait for the development of powerful new technologies, like nuclear propulsion. No one at the dawn of the space age would have believed space probes launched by chemical rockets alone could reach Neptune as early as 1989. What changed? Scientists realized they could use a planet's gravity and orbital momentum to change a spacecraft's course. No nuclear rockets needed. If you're willing to wait a bit, the solar system is yours.

    How about this? Astronomers discovered half of the Milky Way satellite galaxies we know about within the last 2 years.

    Try not to focus so much on the destination. It's the journey that matters.

    March 14, 2008 11:51 AM
  • Antitax said:

    Okay. I had the same impatience in my guitar tuition. Then I saw an interview of guitarist Eric Johnson who told the same advice that you give : "Try to enjoy the process, don't focus solely on the expected result". I'll try to enjoy the process of science. Even exploring the wrong directions is worthwhile exploration, after all. If there was no way to err, there would be no merit in finding.

    March 14, 2008 7:30 PM
  • Lamoure Tribune said:

    Wasn't a similar  experiment used by Michelson and Morley used as an attempt to detect the pre-Einstein "Aether" that was supposed to be the medium for light?

    May 10, 2008 12:33 AM

About Francis Reddy

Francis Reddy
  Francis Reddy is a senior editor with Astronomy magazine.
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