10 to the minus 19! It's mind boggling. Semiconductor process nodes constantly boggle my mind, and yet they sit at a cool 10 to the minus 9. These vibrations are smaller relative to a CPU transistor than a CPU transistor is to me.
LIGO scientist here. The way this is presented can be a little deceptive - the isolation is very frequency dependent. At high frequencies (>10Hz), the pendulums and blade springs in the suspension isolate the mirrors very well, so they are moving by only these small amplitudes (10^-19 meters). But at low frequencies (<1Hz) the isolation ratio is essentially 1, so the amplitude of the mirror motion is roughly the same as that of the ground (about 10^-6 meters).
Yes, which makes sense physically. If the earth's rotation slowed by a constant velocity, in order to damp that motion the mirrors would have to displace themselves in the opposite velocity. Of course, there's no room for them to do so, so damping such low frequencies is not possible.
That's impressive. They didn't have to put it in orbit to get sufficient vibration isolation. The eLISA team must be so frustrated about this.[2] Their gravitational wave detector is in orbit at the L1 point, and their test masses just float in space. But they're not quite ready to turn everything on; that happens in early March.
LISA and LIGO aren't in competition. They are very different projects trying to be sensitive to very different frequencies. (Likewise, Hubble isn't competing with ground-based arrays of radar antenna even though both are looking for electromagnetic waves.)
Furthermore, the only satellite currently in orbit is the LISA pathfinder mission, which is just a testbed for some of the requisite tech. It is incapable of detecting gravitational waves.
The multiple pendulum systems sound really cool. I wish they would put up more images, and high resolution ones, to show what is going on from different angles.
That averages out over the timespan involved in gravitational wave detection. The waves detected by LIGO are on the order of 100 Hz while molecular vibrations are many orders of magnitude higher.
