InSight: Mars’ crust is thin, and its interior is many layered with a molten core
Scientists yesterday released results from the seismometer on the Mars InSight lander that suggest that the crust of the red planet is thin and that its interior is many layered with a molten core.
[T]wo moderate quakes, at magnitude 3.7 and 3.3, have been treasure troves for the mission. Traced to Cerberus Fossae, deep fissures in the crust 1600 kilometers east of the landing site that were suspected of being seismically active, the quakes sent a one-two punch of compressive pressure (P) waves, followed by sidewinding shear (S) waves, barreling toward the lander. Some of the waves were confined to the crust; others reflected off the top of the mantle. Offsets in the travel times of the P and S waves hint at the thickness of the crust and suggest distinct layers within it, Brigitte Knapmeyer-Endrun, a seismologist at the University of Cologne, said in an AGU presentation. The top layer may reflect material ground up in the planet’s first billion years, a period of intense asteroid bombardment, says Steven Hauck, a planetary scientist at Case Western Reserve University.
At 20 or 37 kilometers thick, depending on whether the reflections accurately trace the top of the mantle, the martian crust appears to be thinner than Earth’s continental crust—a surprise. Researchers had thought that Mars, a smaller planet with less internal heat, would have built up a thicker crust, with heat escaping through limited conduction and bouts of volcanism. (Though Mars is volcanically dead today, giant volcanoes dot its surface.) A thin crust, however, might mean Mars was losing heat efficiently, recycling its early crust, rather than just building it up, perhaps through a rudimentary form of plate tectonics, Mojzsis says.
The thin crust provides a solid basis for explaining the large volcanoes and vast lava plains on the planet. Combined with the light gravity, magma would have found an easier path to the surface. Handed this knowledge, planetary geologists can now make a first stab at outlining more precisely the planet’s early volcanic history.
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You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
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Scientists yesterday released results from the seismometer on the Mars InSight lander that suggest that the crust of the red planet is thin and that its interior is many layered with a molten core.
[T]wo moderate quakes, at magnitude 3.7 and 3.3, have been treasure troves for the mission. Traced to Cerberus Fossae, deep fissures in the crust 1600 kilometers east of the landing site that were suspected of being seismically active, the quakes sent a one-two punch of compressive pressure (P) waves, followed by sidewinding shear (S) waves, barreling toward the lander. Some of the waves were confined to the crust; others reflected off the top of the mantle. Offsets in the travel times of the P and S waves hint at the thickness of the crust and suggest distinct layers within it, Brigitte Knapmeyer-Endrun, a seismologist at the University of Cologne, said in an AGU presentation. The top layer may reflect material ground up in the planet’s first billion years, a period of intense asteroid bombardment, says Steven Hauck, a planetary scientist at Case Western Reserve University.
At 20 or 37 kilometers thick, depending on whether the reflections accurately trace the top of the mantle, the martian crust appears to be thinner than Earth’s continental crust—a surprise. Researchers had thought that Mars, a smaller planet with less internal heat, would have built up a thicker crust, with heat escaping through limited conduction and bouts of volcanism. (Though Mars is volcanically dead today, giant volcanoes dot its surface.) A thin crust, however, might mean Mars was losing heat efficiently, recycling its early crust, rather than just building it up, perhaps through a rudimentary form of plate tectonics, Mojzsis says.
The thin crust provides a solid basis for explaining the large volcanoes and vast lava plains on the planet. Combined with the light gravity, magma would have found an easier path to the surface. Handed this knowledge, planetary geologists can now make a first stab at outlining more precisely the planet’s early volcanic history.
Readers!
Every February I run a fund-raising drive during my birthday month. This year I celebrate my 72nd birthday, and hope and plan to continue writing and posting on Behind the Black for as long as I am able.
I hope my readers will support this effort. As I did in my November fund-raising drive, I am offering autographed copies of my books for large donations. Donate $250 and you can have a choice of the hardback of either Genesis: the Story of Apollo 8 or Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space. Donate $200 and you can get an autographed paperback copy of either.
Please consider supporting my work here at Behind the Black. My analysis of space, politics, and culture, taken from the perspective of an historian, is almost always on the money and ahead of the game. For example, in 2020 I correctly predicted that the COVID panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Every one of those 2020 conclusions has turned out right.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
So with a thin crust I would expect the seismometer could pick up the impact of a booster or other item IFF it hit in a relatively close but known location.
A thin Martian crust would be somewhat surprising. I’d thought it would be thick for the reasons cited. If Mars is ‘”. . . losing heat efficiently . . “, how, exactly, is that accomplished?
So Mars is a New York pizza and not a Chicago pizza.
I am with Blair Ivey on this one, the Martian moons are not much more than captured astroids, the tidal pull would be insufficient to keep a large hot molten core for this reason, unlike earth. Let’s explore other factors.
A meteor impact to create a hole in the Martian surface as big as the Helena’s basin “without a thick crust” would’ve broken the planet, or had been filled with molten core lava. (note that Mars does not have rings, or a moon formed from the debris)
The observed evidence suggest a hypothesis that the Helena’s impact created the Thyrsus bulge on the opposite side of the planet. The fractured “thick” crust allowed the volcanoes to relieve the pressure as the fragments of the surface pushed softly, over millions of years, back into their resting possibly floating position.
This occurred long after the entire northern hemisphere was flattened thousands of feet lower than the southern hemisphere by what could’ve been an immense impact, or a minutes long plunge through an atmosphere of a gas giant… or through the edge of the sun itself if Mars was a moon of a theoretical missing planet where the astroid belt is now. (something happened to cover Mars with craters… )
Either way, Mars has had a good reason to still have a molten core.