Mars Has a Thick Crust. Its Internal Heat Mainly Comes from Radioactivity

Elevation data of Mars featuring the lower elevations of the northern lowlands primarily in blue and the much higher elevations of the southern highlands primarily in orange and red. (Credit: MOLA Science Team)

How thick is the crust of Mars? This question is what a recent study published in Geophysical Research Letters attempted to answer as it reported on data from a magnitude 4.7 marsquake recorded in May 2022 by NASA’s InSight lander, which remains the largest quake ever recorded on another planetary body. As it turns out, this data helped provide estimates of Mars’ global crustal thickness, along with a unique discovery regarding the crust in the northern and southern hemispheres, and how the interior of Mars produces its heat.

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Could We Resurrect the Spitzer Space Telescope?

NASA's Spitzer Space Telescope ceased operations in 2020. A new mission might bring it back to life. Image Credit: Rhea Space Activity

NASA’s Spitzer Space Telescope served the astronomy community well for 16 years. From its launch in 2003 to the end of its operations in January 2020, its infrared observations fuelled scientific discoveries too numerous to list.

Infrared telescopes need to be kept cool to operate, and eventually, it ran out of coolant. But that wasn’t the end of the mission; it kept operating in ‘warm’ mode, where observations were limited. Its mission only ended when it drifted too far away from Earth to communicate effectively.

Now the US Space Force thinks they can reboot the telescope.

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A Few Interstellar Objects Have Probably Been Captured

Artist’s impression of the first interstellar asteroid/comet, "Oumuamua". This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser

When Oumuamua travelled through our Solar System back in 2017, people around the world paid attention. It was the first Interstellar Object (ISO) astronomers had ever identified. Then in August 2019, Comet 2I Borisov travelled through our Solar System, becoming the second ISO to cruise through for a visit. Together, the visiting ISOs generated a wave of inquiry and speculation.

There’s bound to be more ISOs than just those two, and a new study says our Solar System has probably captured some of these interstellar visitors, though they don’t stay for long.

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Astronomers Find an Earth-Sized World That May Be Carpeted in Volcanoes

LP 791-18 d, shown here in an artist's concept, is an Earth-size world about 90 light-years away. The gravitational tug from a more massive planet in the system, shown as a blue disk in the background, may result in internal heating and volcanic eruptions – as much as Jupiter’s moon Io, the most geologically active body in the solar system. Credits: NASA’s Goddard Space Flight Center/Chris Smith (KRBwyle)

Astronomers think they’ve found an extrasolar planet covered in volcanoes like Jupiter’s moon Io, but this world is about the same size as Earth. Designated LP 791-18 d, the planet is probably tidally locked around a small, red dwarf star about 90 light-years away in the constellation Crater. There are two other more massive planets in the system, and their tidal interactions could cause enough tidal flexing that it unleashes planet-wide volcanoes on LP 791-18 d.

Planet d is located within the habitable zone of the star, and with all the other conditions, astronomers think it might be temperate enough on the permanent night side of this world to allow water to exist.

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Saturn's Rings are Much Younger Than the Planet

Light streams through Saturn’s rings. Credit: NASA/JPL/Space Science Institute

The rings of Saturn are an amazing sight. They are so iconic that it is hard to imagine Saturn without its rings. But throughout most of Saturn’s history, it didn’t have rings. The rings are much younger than the planet itself, and we now have good evidence to prove it.

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Four of Uranus’ Moons Might Have Liquid Oceans, Too

Recent computer models estimate the likelihood of interior oceans in four of Uranus’ major moons: Ariel, Umbriel, Titania, and Oberon, but Miranda is likely too small to sustain enough heat for an interior ocean. (Credit: NASA/JPL-Caltech)

The study of ocean worlds, planetary bodies with potential interior reservoirs of liquid water, has come to the forefront in terms of astrobiology and the search for life beyond Earth. From Jupiter’s Galilean Moons to Saturn’s Titan and Mimas to Neptune’s Triton and even Pluto, scientists are craving to better understand if these worlds truly possess interior bodies of liquid water. But what about Uranus and its more than two dozen moons? Could they harbor interior oceans, as well?

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JWST Finds a Comet Still Holding Onto Water in the Main Asteroid Belt

This artist's illustration shows the rocky body of a comet with a detailed, cratered surface. Glowing rays emanate from the rocky surface like sunlight through clouds, representing water ice being vapourised by the heat of the Sun. Image Credit: NASA, ESA

Comets are instantly recognizable by their tails of gas and dust. Most comets originate in the far, frozen reaches of our Solar System, and only visit the inner Solar System occasionally. But some are in the Main Asteroid Belt, mixed in with the debris left over after the Solar System formed.

Astronomers just found water vapour coming from one of them.

“With Webb’s observations of Comet Read, we can now demonstrate that water ice from the early Solar System can be preserved in the asteroid belt.”

Michael Kelley, University of Maryland
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Astronomers Prepare for the Next Thousand Years of Hazardous Asteroid Impacts

This diagram shows the orbits of 2,200 potentially hazardous objects as calculated by JPL’s Center for Near Earth Object Studies (CNEOS). Highlighted is the orbit of the double asteroid Didymos, the target of NASA’s Double Asteroid Redirect Test (DART) mission. Credit: NASA/JPL-Caltech

It is as inevitable as the rising of the Sun and the turning of the tides. Someday another large rock from space will crash into the Earth. It has happened for billions of years in the past and will continue to happen for billions of years into the future. So far humanity has been lucky, as we have not had to face such a catastrophic threat. But if we are to survive on this planet for the long term, we will have to come to terms with the reality of hazardous asteroids and prepare ourselves.

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Life Probably Didn't Have a Hand in Creating Organic Deposits on the Surface of Mars

ExoMars Trace Gas Orbiter analyses the martian atmosphere. Credit: ESA/ATG medialab

At this very moment, eleven robotic missions are exploring Mars, a combination of orbiters, landers, rovers, and one aerial vehicle (the Ingenuity helicopter). Like their predecessors, these missions are studying Mars’ atmosphere, surface, and subsurface to learn more about its past and evolution, including how it went from a once warmer and wetter environment to the freezing, dusty, and extremely dry planet we see today. In addition, these missions are looking for evidence of past life on Mars and perhaps learning if and where it might still exist today.

One particularly interesting issue is how the atmosphere of Mars – primarily composed of carbon dioxide (CO2) – is relatively enriched with Carbon-13 (13C), aka. “heavy carbon.” For years, scientists have speculated that the ratio of this isotope to “light carbon” (12C) might be responsible for organics found on the surface (a sign of biological processes!). But after analyzing data from the ESA’s ExoMars Trace Gas Orbiter (TGO) mission, an international team led by The Open University determined that these organics may be “abiotic” in origin (i.e., not biological).

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