The European Space Agency Green-Lit Its "LISA" Mission, This Past Week... In 2035 Or So, It Will Measure Ripples In Space-Time

The cube at left is a precision engineered marvel. . . of highly refined gold and platinum. One of six, in three small spacecraft -- about the size of three eggs, each.

LISA will use pairs of these cubes as "test masses" -- which free-float inside each of the three small ships, perfectly aligned as a vast. . . triangle, trailing Earth, in its orbit around the Sun by several million miles. Any gravitational waves passing through our local group will cause minute, temporary variances in the distances between the masses in these mini-ships, and the mission will track them, using laser interferometry.

This will require measuring laser beams from one spacecraft to the other and then superimposing their signal to determine changes in the masses’ distances down to a few billionths of a millimeter. Here's the latest, from ESA.int:

. . .LISA is not just one spacecraft but a constellation of three. They will trail Earth in its orbit around the Sun, forming an exquisitely accurate equilateral triangle in space. Each side of the triangle will be 2.5 million km long (more than six times the Earth-Moon distance), and the spacecraft will exchange laser beams over this distance. The launch of the three spacecraft is planned for 2035, on an Ariane 6 rocket. . . .

“LISA is an endeavour that has never been tried before. Using laser beams over distances of several kilometres, ground-based instrumentation can detect gravitational waves coming from events involving star-sized objects – such as supernova explosions or merging of hyper-dense stars and stellar-mass black holes. To expand the frontier of gravitational studies we must go to space,” explains LISA lead project scientist Nora Lützgendorf.

“Thanks to the huge distance travelled by the laser signals on LISA, and the superb stability of its instrumentation, we will probe gravitational waves of lower frequencies than is possible on Earth, uncovering events of a different scale, all the way back to the dawn of time. . . .”

Now you know. Grinning ear to ear -- what a sight to see, that would be -- if the Sun, and all our local system. . . suddenly shifted about ten feet, in the blinking of an eye, and then. . . shifted back. Of course, to see that, we'd have to be at least several hundred million miles or so above (or below) the local group, looking down (or up) with a JWST powered space 'scope. Indeed.

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