Scientists have been listening to Mars from Mars' surface.
NASA's InSight lander, which was touched down on Mars in November 2018, gave scientists the unprecedented ability to detect and monitor quakes on Mars. The lander's built-in seismometer detected its first quake in April, and since then, researchers have recorded more potential Mars quakes.
The nature of this shaking is changing what scientists thought they knew about the red planet.
So far, the biggest surprise is that seismic waves on Mars more closely resemble moon quakes earthquakes – which probably means Mars' crust is more dry and broken than we thought.
"So far, we have assumed that the crust of Mars is similar to Earth's crust," Simon Stähler, a Mars seismology researcher at ETH Zurich, said in a press release. Until then, we could only look at it from the outside. "" The Martian crust is internally structured. "
Mars, the moon, and Earth quake for different reasons
Studying seismic activity helps scientists to piece together the history of how rocky planets formed in our solar system move through the planet's interior researchers research the size of its core.
Reading the seismic waves on Mars, scientists hope, wants to reveal clues about what the plant's inside looks like and how it's changing.
"Seismology is how to get the details," Mark Panning, a seismologist on the NASA InSight team, told Business Insider.
Not all quakes are created equal. When the Earth shakes, it's because tectonic plates in the crust are clashing at fault lines. Mars does not have tectonic plates, though. So scientists think the quakes probably come from a constant internal-cooling process, which happens to be most rocky planets. As the core cools, the material contracts, which causes stress to build. This eventually cracks the crust and causes a quake.
On Earth, the source of seismic waves is easily detectable, since the crust is relatively uniform, solid rock (which has been melted and re-paved by volcanic activity over millions of years). That rock also has water in it, which absorbs energy, causing waves to out the faster. That's why earthquakes last for just a few minutes.
On the moon, however, can last longer than an hour.
"A moon quake builds up for minutes, then decays away for an hour or more." It looks very different "Panning said. It's been really dry and really broken up. It's been getting hit by meteorites. "
Still, researchers expected quakes on Mars to fall more on the Earth-like end of the spectrum. That's because they thought the planets had given it a lot of volcanic activity and water.
But the initial data suggests that this is not the case.
Mars is polar ice cap NASA / JPL-Caltech / MSSS
So far, the length of Mars quakes seems to fall somewhere in the middle of the moon's and Earth's, at about 10 to 20 minutes. Mars, therefore, appears to be a little more seismically active than the moon, but a lot less than Earth.
Mars' seismic waves also reverberate more than waves on Earth, and more like to moon quakes.
"It's bouncing off all those broken-up bits, so that gives you something that loads a long time," Panning said.
This is the moon that smashes into the sky.
The artist's representation below shows how seismic waves from a mars quake might move through the red planet's interior.
The animation, made by an InSight seismologist at ETH Zurich, shows the different types of waves the InSight team is studying. The blue waves are the initial bouncy pulses that spread quickly from the quake's source. The red ones follow as a result, and seismologists can use the lag between them to calculate how far away the quake's source is.
crusting materials – their reverberations are the moon-like qualities of Mars' crust.
The researchers expected Mars' crust to be more dry and broken than Earth's, but not quite this much. They do not know what to make of the new finding.
Much more to learn
A few dozen Mars quakes are not enough to reveal the red planet's secrets, however.
"Mars is now," Panning said. "That's telling you how much Mars is evolving over time."
So far, the signals from Mars quakes have also been written down. InSight's tools have been picked up.
In fact, a team of InSight seismologists in Zurich had to amplify those seismic signals by a factor of 10 million in order to accurately simulate the shaking on the scale of an earthquake.
For these reasons, the InSight team is still waiting for a big quake that travels through the planet's core.
"Then we can start making detailed pictures of what the Martian Interior looks like," Panning said. "There's a lot more things going on."
In the meantime, the InSight team tries to fix the lander's "mole," a tool that's supposed to be 16 feet and take Mars' temperature. The mole stopped working properly in February.
In the future, panning would like to see every planetary body's quakes, especially Enceladus, a moon of Saturn from which plots of water shoot out. Even better than a seismometer: a whole network of them.
"Seismology on Earth is almost entirely based on networks of data," Panning said. "I'd love to put seismometers everywhere."