Thanks to NASA’s InSight mission, launched in November 2018, we have been hearing new sounds on Mars. The technology that NASA has placed on Mars has led to the discovery of “Marsquakes” (earthquakes on Mars) and has given us useful data in the exploration of our neighboring planet.

But recently, NASA says that the lander on Mars has been picking up some strange sounds from the red planet. These noises have included a breeze and some rumbling sounds from Mars’ inner core that were too low for the human range of hearing. These noises were taken from the InSight lander’s extremely sensitive seismometer, known as the Seismic Experiment for Interior Structure (SEIS). InSight, or Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, is a two-year mission to explore a part of Mars that we know the least about: its deep interior.

“The recent Marsquake had a surprisingly high-frequency seismic signal compared to what our science team has heard since then,” NASA wrote in a post. “Out of more than 100 events detected to date, 21 are considered to be Marsquakes. The remainder could be quakes as well, but our science team hasn’t ruled out other causes.”

NASA added that SEIS has had no issues identifying the quakes, but because of how sensitive it is, it has had to filter out a lot of background noise while identifying different sounds.

“It’s been exciting, especially in the beginning, hearing the first vibrations from the lander,” said Constantinos Charalambous, an InSight science team member.  “You’re imagining what’s really happening on Mars as InSight sits on the open landscape.”

Quakes on earth and quakes on Mars are different. Mars doesn’t have tectonic plates, which are the cause of quakes on Earth. Martian quakes are caused by cooling and contraction, which create stress fractures on the crust. Mars has a surface covered in craters, which allows quakes to continue for about a minute at a time. On Earth, earthquakes last for only seconds at a time.

Nightfall on Mars has its own unique sounds. The InSight researchers call them “dinks and donks.” It’s probable that these noises are the expansion and contraction of parts inside the seismometer itself, most likely as a result of heat loss. InSight researchers are continuing to study these strange noises on Mars.