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

Dimensional challenges

[SimonInOz]

I read that as a 4.6m cube of gold/platinum alloy and was thinking that was just the sort of thing Lex Luthor would want to steal.

Now come on, it'd make a great show ...

Lousy Democrats

[BitHive]

Shooting all our remaining gold into space so they can shine lasers at it. Typical.

Re:Lousy Democrats

[jandoedel]

it's only the thin coating surrounding the mass that is made of a gold/platinum alloy, not the entire cube. So it is NOT 2kg of gold...
actually gold coatings are used quite a lot for these things.

They have a mass floating freely in space, and surrounding it is this gold/platinum coat, that never touches it, it just flies around it and has microthrusters to keep it away from the central mass. This gold/platinum coat is shielding the mass from some external influences, like the solar magnetic field, so that the central mass only feels the influence of the gravitational waves.

Unlike the "Galaxy sized detector"

[TwineLogic]

This detector would be 3,000,000 miles across when measured from one man-made component to another. The article linked to as a 'galaxy sized detector' is actually about a proposal to observe pulsars looking for the effect of gravitational waves.

When observing pulsars, I assume it is not possible to be 100% of what one is seeing, considering that pulsar observations continue to accumulate and scientists have not had the chance to see a pulsar close-up.

In comparison, using man-made scientific instruments, which are much more under the control of the investigating scientists, to perform the measurement is more trustworthy than observing pulsars. In this regard, the huge scale of the equipment (3 Million Miles) is very significant -- the instruments will be able to make a fine measurement across this distance -- and comparing it with the size of the galaxy is not really a valid comparison.

On the other hand, the snark-value of the comparison was high, and providing the link without these details only raised the snark-tasticness.

Costing

[kakapo]

From memory, LISA is usually listed as being in the $1.5- $2 billion dollar range, which puts in the same category as Hubble or the forthcoming James Webb telescope.

Worth every penny, too, in my opinion.

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:not funded yet

[HBoar]

I think you need to look up what the word 'orbit' means.....

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.

I was like wtf?

[future assassin]

Won't the Ferengi attack the satellites to steal the gold-pressed latinum?