NASA's InSight lander has likely detected its first 'marsquake,' seismologists say

It sounds like a subway train rushing by. But it's something much more exotic: in all likelihood, the first "marsquake" ever recorded by humans. NASA's InSight mission detected the quake on April 6, four months after the lander's highly sensitive seismometer was installed on the Martian surface. The instrument had previously registered the howling winds of the red planet and the motions of the lander's robotic arm. But the shaking picked up this month is believed to be the first quake from Mars' interior.