San Francisco Chronicle - (Sunday)

Quakes enable first detailed look at Mars’ interior

- By Marcia Dunn Marcia Dunn is an Associated Press writer.

CAPE CANAVERAL — A quakemeasu­ring device on Mars is providing the first detailed look at the Red Planet’s interior, revealing a surprising­ly thin crust and a hot molten core beneath the frigid surface.

In a series of articles published last week, scientists reported that the Martian crust is within the thickness range of Earth’s. The Martian mantle between the crust and core is roughly half as thick as Earth’s. And the Martian core is on the high side of what scientists anticipate­d, although smaller than the core of our own nearly twiceasbig planet.

These new studies confirm that the Martian core is molten. But more research is needed to know whether Mars has a solid inner core like Earth’s, surrounded by a molten outer core, according to the internatio­nal research teams.

Stronger marsquakes could help identify any multiple core layers, scientists said Friday.

The findings are based on about 35 marsquakes registered by a French seismomete­r on NASA’s InSight stationary lander, which arrived at Mars in 2018. The domed seismomete­r has actually detected 733 marsquakes so far, but the 35 with magnitudes from 3.0 to 4.0 served as the basis for these studies. Most of the sizable quakes originated in a volcanic region 1,000 miles away where lava may have flowed just millions of years ago.

Mark Panning of NASA’s Jet Propulsion Laboratory, who took part in the crust study, said even the biggest marsquakes are so weak they would barely be felt on Earth. He’s hoping for “the big one” which would make it easier to process the data and define the Martian interior. Current measuremen­ts show Mars’ crust possibly reaching as deep as 12 miles to 23 miles; the mantle extending down nearly 1,000 miles; and the relatively lightweigh­t core with a radius of 1,137 miles.

By comparison, Earth’s crust ranges from a few miles beneath the oceans to more than 45 miles beneath the Himalayas. Earth is almost double the size of Mars.

“By going from cartoon understand­ing of what the inside of Mars looks like, putting real numbers on it … we are able to really expand the family tree of understand­ing” how our solar system’s rocky planet formed, Panning said.

The three studies and a companion article appeared in Thursday’s edition of the journal Science.

Newspapers in English

Newspapers from United States