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Science

European Plan for Gigantic New Gravitational Wave Detector Passes Milestone (sciencemag.org) 35

Posted by msmash from the moving-forward dept.
It's far from a done deal, but plans by European physicists to build a huge new gravitational wave observatory with a radical design received a boost last week. From a report: The European Strategy Forum on Research Infrastructures (ESFRI), which advises European governments on research priorities, added the $2.25 billion observatory, called the Einstein Telescope, to a road map of large science projects ripe for progress. Developers hope the move will give them the political validation needed to transform the Einstein Telescope idea into a project. "This isn't a promise of any funding, but it shows the clear intention to pursue this," says Harald Luck, a gravitational wave physicist at Leibniz University Hannover and the Max Planck Institute for Gravitational Physics and co-chair of the Einstein Telescope steering committee. âoeIt is more of a political commitment."

U.S. gravitational wave physicists welcomed the announcement, too, as they think it may bolster their plans to build a pair of detectors even bigger than the Einstein Telescope in a project called Cosmic Explorer. "In the U.S., I think the momentum is going to start to build," says David Reitze, executive director of the Laser Interferometer Gravitational-Wave Observatory (LIGO) and a physicist at the California Institute of Technology.
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European Plan for Gigantic New Gravitational Wave Detector Passes Milestone More

European Plan for Gigantic New Gravitational Wave Detector Passes Milestone

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  • "steering committee. âoeIt is more" FIX THIS (Score:4, Insightful)

    by correct0r ( 6532614 ) on Monday July 05, 2021 @02:24PM (#61553358)
    FIX THIS SHIT ! Signed, Any decent editor who gives a shit about their job

    • FIX THIS SHIT !

      Signed,

      Any decent editor who gives a shit about their job

      There are no editors left. They have long since automated the process of moving community submissions to the front page.

  • summary (Score:5, Informative)

    by doug141 ( 863552 ) on Monday July 05, 2021 @02:37PM (#61553380)

    LIGO has two 4km arms, in an L shape, Europe's version has 3km arms. They are sensitive to black hole mergers up to 10 billion light years away.
    Einstein Telescope would have three 10km arms, in a triangle instead of an L-shape. 10x the sensitivity, to 45 billion light years "to the edge of the observable universe."
    Cosmic Explorer would have two L-shaped 40km arms to get 10x sensitivity.

  • Unexplained (Score:4, Interesting)

    by Martin S. ( 98249 ) on Monday July 05, 2021 @02:37PM (#61553382) Journal

    Gravity waves stretch and contract space-time, space and time. I have never had a good explanation why stretching time doesn't cancel out the stretching of space.

    • Let's talk about the situation you're in. You are pulled towards the ground mostly by time dilation being greater at your feet than at your head, there is drag on your entire body in that direction. Hardly any space stretching is going on by the Earth. So the two effects aren't equal and don't cancel. An entire galaxy can stretch light from an even more distant object so we notice it, and of course space stretched (and pulled along by rotation even) near black hole or neutron star is another matter (an

      • Re: (Score:1)

        by dvice ( 6309704 )

        > You are pulled towards the ground

        You have it wrong. He is not pulled towards ground. He is floating freely in space. It is the ground that is accelerating towards him. Think of an astronaut floating in a space shuttle. And think the shuttle speeding up. When that happens the astronaut "falls" to the bottom of the ship. But actually astronaut stays in place, it is the ship that moves. At least this is what Einstein was thinking about this matter.

        • Re:Unexplained (Score:5, Insightful)

          by iggymanz ( 596061 ) on Monday July 05, 2021 @04:35PM (#61553574)

          False, that's just one of many layman's explanations. The math says the difference in time dilation is (mostly) responsible for drawing object to Earth.

          Or if you want better layman's explanation by actual physicists, go here

          https://www.youtube.com/watch?... [youtube.com]

          • This is true. I always like to emphasize that as long as you’re consistent and lay it out plainly to avoid confusion, it does not matter which reference frame you prefer or what force definitions are oppositely defined, the math works out to the same result in the end. Otherwise I’d probably have lost it and punched my first EE professor for backwards defined current flow.

        • So are you saying the expansion of the universe *is* (what we perceive as) gravity?

          • > So are you saying the expansion of the universe *is* (what we perceive as) gravity?

            The first /. Nobel!

    • I have never had a good explanation why stretching time doesn't cancel out the stretching of space.
      It does.
      As it stretches out into different "directions".

    • I don't think there is any reason to think they should cancel. Earth's gravity distorts space and objects near the earth (and not on the ground) follow locally "straight" paths that appear curved when viewed from a distance. Space time around the earth is curved, but not in a way where the time and space like components cancel. As another example, an electromagnetic wave has both electric and magnetic fields. For charged particles in some trajectories, these will cancel, but its not generally true - e

    • The wave of "stretch" passes us at the speed of light. But the rate of "stretch" is slow.

      Picture a tank of water, 1m deep. A bouy on the surface, using pulses of sound to measure depth. A wave 1km wide passes the bouy, also at the speed of sound. The bouy could send 1000 pulses before the wave disappears.

    • They do stretch everything out and it does cancel - but not exactly. Thus, it’s not the gravitational wave that is detected, but the distortion - as a quadrupolar wave amplitude - and that’s why [forbes.com] the wave energy doesn’t obey the inverse square law and falls off linearly instead.

      An imperfect analogy is you have two bits floating on water where they can only see each other and not the water, when a wave passes - they drift slightly closer and then slightly farther apart, much smaller tha

  • "LISA" is the truly gigantic new detector (Score:5, Insightful)

    by ffkom ( 3519199 ) on Monday July 05, 2021 @02:59PM (#61553414)
    ESA has already approved the Laser Interferometer Space Antenna [wikipedia.org], which will be orders of magnitude larger.
    • And almost six orders of magnitude larger. LISA is arranged as an equilateral triangle, 2.5 million kilometers on a side.
    • LISA is an excellent project that has been in development for a couple of decades. Its targeted frequency range is much lower than for the earth based GW observatories - its looking for different types of sources.
      At much much lower frequencies, there is work on using pulsar timing to measure extremely low frequency gravity waves.
      There is also work on atomic interferometers to look at the intermediate frequency range between LIGO style detectors and LISA.
      All good. Gravity waves a a new window on the

      • Re: (Score:2)

        by mattr ( 78516 )

        I was also wondering and looked up LISA. With arms 2.5 million km long the wavelength is much lower so mostly for massive objects. What I don't understand is why not fly LISA at much lower arm lengths, how would that compare to the underground ones that are being planned now?

        • From the wikipedia article it looks like the 2.5M KM is a maximum arm length but they could probably fly a closer separation if they wanted. It looks like the science goals are at the low frequency end, and they wanted as long as was practical, with an original design of 5M KM. At very short arm lengths, the terrestrial GW detectors are probably better because they use resonant optical cavities (Fabry Perot) which incrase their sensitivity. It would be much more difficult to do that in space, espeicially

  • As somebody from the EU:

    It's not my our telescope. It's *everyone*'s telescope.

    Actual scientists don't give a damn where you are from.

    Not letting an American run a very interesting experiment on a machine, just because the EU built it, is scientific insanity.

    • I do understand the spirit of what you're saying, but to nitpick, it is indeed the EU's telescope because the EU is going to pay to build it.

      That said, it's in the EU's interest to invite observing-proposals from all over the world, to encourage non-EU institutions to reciprocate. That improves the quality of research at all observatories.

  • I was wondering why create a very expensive km long L shaped vacuum construction costing a billion on Earth if you can launch 3 micro sats basically for free and do the experiment in orbit.

  • When an observatory detects a possible event, it is one thing. When another observatory confirms, the observation is much stronger.

  • How many of these do we really need? (Score:3)

    by argStyopa ( 232550 ) on Tuesday July 06, 2021 @09:53AM (#61555457) Journal

    I mean, I understand international scientific epeen is involved, but is there such a backlog for observations with LIGO that another multibillion-euro facility is needed?

    I am 1000% for space exploration, settlement, and research, but it's not hard to think of a bunch of better ways to spend those $ than on (functionally) a glorified, narrow-purpose telescope.

    This reminds me of Eisenhower's barely remembered "other" warning (in the same speech where he identified the threat of the military-industrial complex):

    Akin to, and largely responsible for the sweeping changes in our industrial-military posture, has been the technological revolution during recent decades.

            In this revolution, research has become central, it also becomes more formalized, complex, and costly. A steadily increasing share is conducted for, by, or at the direction of, the Federal government. ...

            The prospect of domination of the nation's scholars by Federal employment, project allocation, and the power of money is ever present and is gravely to be regarded.

            Yet in holding scientific discovery in respect, as we should, we must also be alert to the equal and opposite danger that public policy could itself become the captive of a scientific-technological elite.[1]

     

    • The thing to note is that the observatories are additive, not only combined will they be more sensitive but will also help triangulate the sources better so that astronomers can quickly follow up with optical observations. YMMV but I think the results from LIGO are orders of magnitude more interesting and impactful than what was accomplished with something like the LHC.
    • It offer much larger detection radius and sensitivity in the 1-10hz range which LIGO can't do. Gravitational waves detectors are a brand new way of observing the cosmos, If you believe you have a better idea for the use of funds by all means enlighten us.
      • I went to a summer program for high school students in the 80s at Caltech. I used to walk by one of the prototype detectors every day, it was about the length of a bowling lane. I've been following it's progress ever since. The physics and engineering are truly mind boggling- I was stunned when the first result was published. Many physicists devoted their entire career to the project both in technical and political (ie obtaining funding). I think it is one of the greatest achievements of the century.
        • LIGO itself was built as a research prototype and never detected anything, it wasn't until the detectors were replaced with generation 2 "advanced LIGO,' and a slew of other upgrades that they finally got a confirmed signal.
  • having a 'plan' is waaaay far away from having anything news worthy.

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