Biggest Detector To Look For Gravitational Waves

Hugh Pickens sends in coverage in the Telegraph of a joint NASA-ESA experimental mission, to launch around 2020. It involves three spacecraft orbiting the Sun, separated by 3 million miles, each with a payload of two lasers and a 4.6-cm cube of gold-platinum alloy. The point of it all is to look for gravitational waves. The mission is called LISA, a reasonably non-strained acronym for Laser Interferometer Space Antenna. The Telegraph makes a point of LISA being the largest experiment ever constructed (in terms of its dimensions). Neither that newspaper nor the project page at NASA mentions how much the experiment will cost, but it's almost certainly an order of magnitude or more above the $66 million estimated for a gravitational wave detector the size of the galaxy, which we discussed last fall.

Comments

not funded yet

[bcrowell]

I believe the slashdot summary and TFA are misleading, because they make it sound like LISA will definitely be built. According to the WP article, LISA is competing against two other space-based science projects for funding, and the decision won't be made until 2013.

Personally, I would love to see LISA fly. Gravitational waves were first predicted in about 1914. Most aspects of general relativity have been tested pretty thoroughly at this point, but almost a century later we still have no direct confirmation that gravitational waves exist (although there is very strong indirect evidence). And if they can be detected, then it opens up an entirely new way of doing astronomy: not with electromagnetic waves, but with gravitational ones.

Re:not funded yet

[Chris Burke]

The NASA and JPL mission pages don't make it clear that this is unfunded as of yet either, which is annoying since I've been reading up on this experiment for some time and am pretty excited about it!

I, too, would love to see LISA fly. We really do need robust tests of gravity waves, and a whole new world of observations will open up to us if it pans out.

One of the coolest things about the mission itself that I read about is the 'drag free' aspect. To ensure that the test masses are in free-fall around the sun without interference by things like the pesky solar wind, they're housed free-floating in a chamber inside the LISA spacecrafts themselves. The spacecraft absorbs the solar wind or other outside forces while measuring any change in relative position to the test mass and using micro-thrusters to keep itself centered on the mass and thus in the same free-fall drag-less orbit. Effin cool imo, even if I don't think it's first time it's been done. :)

Re:So I didn't RTFA

[jasno]

I guess they do carry energy, and we think we've seen proof of it: http://en.wikipedia.org/wiki/Hulse-Taylor_binary.