Seismic waves from quakes detected by NASA’s robotic InSight lander have helped scientists decipher the anatomy of Mars, including the first estimates of the size of its large liquid metal core, thickness of its crust and nature of its mantle.
The findings disclosed on Thursday shed light on what had been a poorly understood internal structure of Earth’s smaller neighbor, and provided a few surprises as well as confirmation that the Red Planet’s center is molten.
The InSight lander, which touched down in 2018 to begin the first mission to study the deep interior of Mars, has detected more than 700 marsquakes, most of modest strength.
Photo: Reuters
Waves generated by quakes vary in speed and shape when journeying through different material inside a planet. Data from InSight’s seismometer instrument, covering about three dozen marsquakes, enabled the contours of the planet’s interior to come into focus.
“The real importance of these findings is that, for the first time, we actually have measurements of dimensions — sizes — of the fundamental building blocks of the planet Mars,” said planetary geophysicist Bruce Banerdt of NASA’s Jet Propulsion Laboratory, the InSight mission’s principal investigator.
“Before this, all we had were comparisons with Earth, theoretical calculations and indirect inferences from other observations like the trace isotope chemistry of Martian meteorites,” Banerdt added.
The Martian core, the innermost geologic layer, was found to have a diameter of approximately 3,660km, larger than previously thought.
This suggests that the core, made up mostly of iron and nickel, is less dense than previously known, with lighter elements such as sulfur, oxygen, carbon and hydrogen representing an unexpectedly large proportion.
The Martian crust, the outermost layer, is geologically quite different from Earth’s, the crust of which is divided into immense plates that move inexorably over a rocky inner layer called a mantle in a process called plate tectonics. Crust at certain spots below Earth’s oceans is constantly recycled.
“Since we don’t have active plate tectonics on Mars, nothing similar is happening there. This also means that the crust of Mars is very old,” said University of Cologne seismologist Brigitte Knapmeyer-Endrun, who led one of the three studies on the Martian interior published in the journal Science.
The global average crust thickness was found to be 24km to 72km. There was significant variability in the thickness, with a difference of about 100km between the minimum in a region called the Isidis Planitia impact basin and the maximum beneath a region called the Tharsis, a volcanic plateau.
“The crust at the landing site consists of at least two layers, and the global average crustal thickness is less than predicted by some previous models. The crust is rather thin,” Knapmeyer-Endrun said.
Earth’s crust thickness also varies, between almost zero near deep underwater mid-ocean ridges, where new crust is formed, to about 80km beneath the Himalayas.
The Martian mantle, sandwiched between the crust and core, extends about 1,560km below the surface. Its composition differs from Earth’s, suggesting that the two planets arose from different material when they formed more than 4.5 billion years ago.
Mars, the fourth planet from the sun, has a diameter of about 6,791km, compared with Earth’s diameter of about 12,755km.
Banerdt said the new findings allow scientists to test theories of planet formation.
“The understanding we will gain from this will apply not only to Mars but to the formation and history of the Earth and any other rocky planet in our solar system or beyond,” Banerdt added.
The pitch is a classic: A young celebrity with no climbing experience spends a year in hard training and scales Mount Everest, succeeding against some — if not all — odds. French YouTuber Ines Benazzouz, known as Inoxtag, brought the story to life with a two-hour-plus documentary about his year preparing for the ultimate challenge. The film, titled Kaizen, proved a smash hit on its release last weekend. Young fans queued around the block to get into a preview screening in Paris, with Inoxtag’s management on Monday saying the film had smashed the box office record for a special cinema
CRITICISM: ‘One has to choose the lesser of two evils,’ Pope Francis said, as he criticized Trump’s anti-immigrant policies and Harris’ pro-choice position Pope Francis on Friday accused both former US president Donald Trump and US Vice President Kamala Harris of being “against life” as he returned to Rome from a 12-day tour of the Asia-Pacific region. The 87-year-old pontiff’s comments on the US presidential hopefuls came as he defied health concerns to connect with believers from the jungle of Papua New Guinea to the skyscrapers of Singapore. It was Francis’ longest trip in duration and distance since becoming head of the world’s nearly 1.4 billion Roman Catholics more than 11 years ago. Despite the marathon visit, he held a long and spirited
CARTEL ARRESTS: The president said that a US government operation to arrest two cartel members made it jointly responsible for the unrest in the state’s capital Mexican President Andres Manuel Lopez Obrador on Thursday blamed the US in part for a surge in cartel violence in the northern state of Sinaloa that has left at least 30 people dead in the past week. Two warring factions of the Sinaloa cartel have clashed in the state capital of Culiacan in what appears to be a fight for power after two of its leaders were arrested in the US in late July. Teams of gunmen have shot at each other and the security forces. Meanwhile, dead bodies continued to be found across the city. On one busy street corner, cars drove
‘DISAPPEARED COMPLETELY’: The melting of thousands of glaciers is a major threat to people in the landlocked region that already suffers from a water shortage Near a wooden hut high up in the Kyrgyz mountains, scientist Gulbara Omorova walked to a pile of gray rocks, reminiscing how the same spot was a glacier just a few years ago. At an altitude of 4,000m, the 35-year-old researcher is surrounded by the giant peaks of the towering Tian Shan range that also stretches into China, Kazakhstan and Uzbekistan. The area is home to thousands of glaciers that are melting at an alarming rate in Central Asia, already hard-hit by climate change. A glaciologist, Omarova is recording that process — worried about the future. She hiked six hours to get to