Mars Has a Surprise Layer of Molten Rock Inside (nature.com) 35
Alexandra Witze reports via Nature: A meteorite that slammed into Mars in September 2021 has rewritten what scientists know about the planet's interior. By analysing the seismic energy that vibrated through the planet after the impact, researchers have discovered a layer of molten rock that envelops Mars's liquid-metal core. The finding, reported today in two papers in Nature, means that the Martian core is smaller than previously thought. It also resolves some lingering questions about how the red planet formed and evolved over billions of years.
The discovery comes from NASA's InSight mission, which landed a craft with a seismometer on Mars's surface. Between 2018 and 2022, that instrument detected hundreds of "marsquakes' shaking the planet. In July 2021, on the basis of the mission's observations of 11 quakes, researchers reported that the liquid core of Mars seemed to have a radius of around 1,830 kilometers3. That was bigger than many scientists were expecting. And it suggested that the core contained surprisingly high amounts of light chemical elements, such as sulfur, mixed with iron. But the September 2021 meteorite impact "unlocked everything," says Henri Samuel, a geophysicist at the Institute of Earth Physics of Paris and lead author of one of today's papers1. The meteorite struck the planet on the side opposite to where InSight was located. That's much more distant than the marsquakes that InSight had previously studied, and allowed the probe to detect seismic energy traveling all the way through the Martian core4. "We were so excited," says Jessica Irving, a seismologist at the University of Bristol, UK, and a co-author of Samuel's paper.
For Samuel, it was an opportunity to test his idea that a molten layer of rock surrounds Mars's core5. The way the seismic energy traversed the planet showed that what scientists had thought was the boundary between the liquid core and the solid mantle, 1,830 kilometers from the planet's centre, was actually a different boundary between liquid and solid. It was the top of the newfound layer of molten rock meeting the mantle (see 'Rethinking the Martian core'). The actual core is buried beneath that molten-rock layer and has a radius of only 1,650 kilometers, Samuel says. The revised core size solves some puzzles. It means that the Martian core doesn't have to contain high amounts of light elements -- a better match to laboratory and theoretical estimates. A second liquid layer inside the planet also meshes better with other evidence, such as how Mars responds to being deformed by the gravitational tug of its moon Phobos.
The second paper in Nature today2, from a team independent of Samuel's, agrees that Mars's core is enveloped by a layer of molten rock, but estimates that the core has a radius of 1,675 kilometers. The work analyzed seismic waves from the same distant meteorite impact, as well as simulations of the properties of mixtures of molten elements such as iron, nickel and sulfur at the high pressures and temperatures in the Martian core. Having molten rock right up against molten iron "appears to be unique," says lead author Amir Khan, a geophysicist at ETH Zurich. "You have this peculiarity of liquid-liquid layering, which is something that doesn't exist on the Earth." The molten-rock layer might be left over from a magma ocean that once covered Mars. As it cooled and solidified into rock, the magma would have left behind a deep layer of radioactive elements that still release heat and keep rock molten at the base of the mantle, Samuel says.
The discovery comes from NASA's InSight mission, which landed a craft with a seismometer on Mars's surface. Between 2018 and 2022, that instrument detected hundreds of "marsquakes' shaking the planet. In July 2021, on the basis of the mission's observations of 11 quakes, researchers reported that the liquid core of Mars seemed to have a radius of around 1,830 kilometers3. That was bigger than many scientists were expecting. And it suggested that the core contained surprisingly high amounts of light chemical elements, such as sulfur, mixed with iron. But the September 2021 meteorite impact "unlocked everything," says Henri Samuel, a geophysicist at the Institute of Earth Physics of Paris and lead author of one of today's papers1. The meteorite struck the planet on the side opposite to where InSight was located. That's much more distant than the marsquakes that InSight had previously studied, and allowed the probe to detect seismic energy traveling all the way through the Martian core4. "We were so excited," says Jessica Irving, a seismologist at the University of Bristol, UK, and a co-author of Samuel's paper.
For Samuel, it was an opportunity to test his idea that a molten layer of rock surrounds Mars's core5. The way the seismic energy traversed the planet showed that what scientists had thought was the boundary between the liquid core and the solid mantle, 1,830 kilometers from the planet's centre, was actually a different boundary between liquid and solid. It was the top of the newfound layer of molten rock meeting the mantle (see 'Rethinking the Martian core'). The actual core is buried beneath that molten-rock layer and has a radius of only 1,650 kilometers, Samuel says. The revised core size solves some puzzles. It means that the Martian core doesn't have to contain high amounts of light elements -- a better match to laboratory and theoretical estimates. A second liquid layer inside the planet also meshes better with other evidence, such as how Mars responds to being deformed by the gravitational tug of its moon Phobos.
The second paper in Nature today2, from a team independent of Samuel's, agrees that Mars's core is enveloped by a layer of molten rock, but estimates that the core has a radius of 1,675 kilometers. The work analyzed seismic waves from the same distant meteorite impact, as well as simulations of the properties of mixtures of molten elements such as iron, nickel and sulfur at the high pressures and temperatures in the Martian core. Having molten rock right up against molten iron "appears to be unique," says lead author Amir Khan, a geophysicist at ETH Zurich. "You have this peculiarity of liquid-liquid layering, which is something that doesn't exist on the Earth." The molten-rock layer might be left over from a magma ocean that once covered Mars. As it cooled and solidified into rock, the magma would have left behind a deep layer of radioactive elements that still release heat and keep rock molten at the base of the mantle, Samuel says.
Okie dokie. Next on the to-do list ... (Score:5, Interesting)
Get a drilling ship to Mars with some nukes, get that core [wikipedia.org] rotating again - "somehow" - to start the magnetic field back up to protect it from the solar winds, build up some oxygen in the atmosphere and we're all set.
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I "recall" watching frame by frame the end sequence when Arnold is kicked out outside without oxygen just as they restart the oxygen/atmosphere generator. The special effects from back then were hilarious with his eyes almost popping out of his head, it was kind of cartoonish but very funny.
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I "recall" watching frame by frame the end sequence when Arnold is kicked out outside without oxygen just as they restart the oxygen/atmosphere generator. The special effects from back then were hilarious with his eyes almost popping out of his head, it was kind of cartoonish but very funny.
The Two Weeks Lady's head effect was pretty laugh-worthy as well. Still a fun movie.
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yeah both of them were funny...
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Underground living is the way to go. So many benefits.
Just need to simulate that homeworld sunlight spectrum at appropriate times, since it turns out that is quite important for long-term Human health and well-being.
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Then why bother going to Mars?
What you want is surface area to mine and extract minerals from (it's almost irrelevant whether you look at the few % of metal rich small bodies, or the 90%+ more normal bodies).
You'll never get Mars to have an Earth-like gravity unless you add almost every body not in orbit around Jupiter (which is going to incur some transport costs), and you'd use most of the asteroid belt just trying to get the atmospheric pressure up
A molten layer would be somewhere, wouldn't it? (Score:3)
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Liquid metal core, radioactive.
Hard crust at the top.
Yeah, what would be the other possibility?
Probably TFA is missing the point of the research?
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At some point in it's history, yes. But you've got the gist here : Maybe a planet similar to it that's twice as old?
Mars is (checks notes) a touch over half the diameter of Earth (6792 versus 12742 km), but only about 1/10th the mass of Earth (0.642 vs 5.97 *10^24 kg) (Geometrically, you'd expect 1/8th, but there is significant compression in the bottom 6000km of the Earth's structure that Mars just does not have.) That works out as me
Life? (Score:3)
It occurs to me, it's believed by many that life on Earth either started or crept down deep into the Earth, where it's warm.
If that' the case, wouldn't have life on Mars likely have survived there?
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It occurs to me, it's believed by many that life on Earth either started or crept down deep into the Earth, where it's warm.
If that' the case, wouldn't have life on Mars likely have survived there?
The main hypothesis that involves the Earth's own heat is that life started/formed around the heat vents in the ocean floor. So, if Mars had a large body of water on it at one point, with some decent heat vents pouring chemicals into it? It's possible life was there. Life doesn't tend to survive within the molten material itself. At least not life that we here on Earth understand at this point. If the transition from water-bearing to desert planet was slow enough, perhaps life could evolve to survive in the
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No, what I've seen is the hypothesis that life could also have evolved many miles underneath that. In any case, it's believed to have moved down since then, and permeated the crust into internal chasms, often where water is scarce and doesn't evaporate away.
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No, what I've seen is the hypothesis that life could also have evolved many miles underneath that. In any case, it's believed to have moved down since then, and permeated the crust into internal chasms, often where water is scarce and doesn't evaporate away.
Hmm. Hadn't heard of this theory before. Looks like I have more research to do.
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Wish I could recall where I'd heard that one. Some YouTube video about abiogenesis no doubt.
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Even Gold puts the origin of life no more than a few miles below the surface of the oceans. He asserts (with no substantive evidence) that life then migrated both upwards (to the atmosphere-[lithosphere or hydrosphere] boundary); for wh
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So, if Mars had a large body of water on it at one point, with some decent heat vents pouring chemicals into it? It's possible life was there.
Not if. It is a near certainty that not only was mars covered in water, but lots of vents.
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So basically... (Score:1)
Mars is a planetary sized Pop Tart. Delicious on the outside, molten lava on the inside.
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Mars is a planetary sized Pop Tart. Delicious on the outside, molten lava on the inside.
Perhaps a Hot Pocket or Pizza Rolls?
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What I want to know is where do you get a planet sized toaster?
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What I want to know is where do you get a planet sized toaster?
See that bright ball in the sky? It's been toasting planets for billions of years.
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What I want to know is where do you get a planet sized toaster?
Same store as the vacuum cleaner in Spaceballs....
Surprise Magma. (Score:3)
Hyuuuge Molten Layer (Score:2)
OK, I'm putting on my Red Planet MAGMA hat.
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Make America Generate Magma Again!
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Title! (Score:2)