Posted on 08/08/2023 11:51:42 AM PDT by Red Badger
Using NASA’s InSight Mars lander, scientists have precisely measured Mars’ rotation, detecting a subtle acceleration and the planet’s wobble due to its molten core. This study offers unprecedented insights into the Martian core’s size and shape, providing vital information for understanding Mars’ internal structure. Credit: NASA/JPL-Caltech/UArizona.
Data sent by the spacecraft before it retired last December has provided new details about how fast the planet rotates and how much it wobbles.
Scientists have made the most precise measurements ever of Mars’ rotation, for the first time detecting how the planet wobbles due to the “sloshing” of its molten metal core. The findings, detailed in a recent Nature paper, rely on data from NASA’s InSight Mars lander, which operated for four years before running out of power during its extended mission in December 2022.
To track the planet’s spin rate, the study’s authors relied on one of InSight’s instruments: a radio transponder and antennas collectively called the Rotation and Interior Structure Experiment, or RISE. They found the planet’s rotation is accelerating by about 4 milliarcseconds per year² – corresponding to a shortening of the length of the Martian day by a fraction of a millisecond per year.
NASA InSight's Final Selfie
NASA’s InSight lander captured this selfie on April 24, 2022, the 1,211th Martian day, or sol, of the mission. Dust on its solar panels caused the lander to lose power in December of that year, but data recorded by InSight’s instruments is still leading to new science. Credit: NASA/JPL-Caltech. Credit: NASA/JPL-Caltech
Understanding the Acceleration
It’s a subtle acceleration, and scientists aren’t entirely sure of the cause. But they have a few ideas, including ice accumulating on the polar caps or post-glacial rebound, where landmasses rise after being buried by ice. The shift in a planet’s mass can cause it to accelerate a bit like an ice skater spinning with their arms stretched out, then pulling their arms in.
“It’s really cool to be able to get this latest measurement – and so precisely,” said InSight’s principal investigator, Bruce Banerdt of NASA’s Jet Propulsion Laboratory (JPL) in Southern California. “I’ve been involved in efforts to get a geophysical station like InSight onto Mars for a long time, and results like this make all those decades of work worth it.”
This video explains how NASA’s Deep Space Network – made up of multiple giant antenna dishes arrayed at three roughly equidistant ground stations on Earth – helps conduct radio science around planets, moons, and other planetary bodies. Credit: NASA/JPL-Caltech
VIDEO AT LINK.............
How RISE Works
RISE is part of a long tradition of Mars landers using radio waves for science, including the twin Viking landers in the 1970s and the Pathfinder lander in the late ’90s. But none of those missions had the advantage of InSight’s advanced radio technology and upgrades to the antennas within NASA’s Deep Space Network on Earth. Together, these enhancements provided data about five times more accurate than what was available for the Viking landers.
In the case of InSight, scientists would beam a radio signal to the lander using the Deep Space Network. RISE would then reflect the signal back. When scientists received the reflected signal, they would look for tiny changes in frequency caused by the Doppler shift (the same effect that causes an ambulance siren to change pitch as it gets closer and farther away). Measuring the shift enabled researchers to determine how fast the planet rotates.
NASA InSight Lander Rotation and Interior Structure Experiment (RISE)
This annotated artist’s concept of NASA’s InSight lander on Mars points out the antennas on the spacecraft’s deck. Along with a radio transponder in the lander, these antennas made up an instrument called the Rotation and Interior Structure Experiment, or RISE. Credit: NASA/JPL-Caltech
Experiment Details
“What we’re looking for are variations that are just a few tens of centimeters over the course of a Martian year,” said the paper’s lead author and RISE’s principal investigator, Sebastien Le Maistre at the Royal Observatory of Belgium. “It takes a very long time and a lot of data to accumulate before we can even see these variations.”
The paper examined data from InSight’s first 900 Martian days – enough time to look for such variations. Scientists had their work cut out for them to eliminate sources of noise: Water slows radio signals, so moisture in the Earth’s atmosphere can distort the signal coming back from Mars. So can the solar wind, the electrons and protons flung into deep space from the Sun.
“It’s a historic experiment,” said Le Maistre. “We have spent a lot of time and energy preparing for the experiment and anticipating these discoveries. But despite this, we were still surprised along the way – and it’s not over, since RISE still has a lot to reveal about Mars.”
Martian Core Measurements
RISE data was also used by the study authors to measure Mars’ wobble – called its nutation – due to sloshing in its liquid core. The measurement allows scientists to determine the size of the core: Based on RISE data, the core has a radius of roughly 1,140 miles (1,835 kilometers).
The authors then compared that figure with two previous measurements of the core derived the from spacecraft’s seismometer. Specifically, they looked at how seismic waves traveled through the planet’s interior – whether they reflected off the core or passed through it unimpeded.
Taking all three measurements into account, they estimate the core’s radius to be between 1,112 and 1,150 miles (1,790 and 1,850 kilometers). Mars as a whole has a radius of 2,106 miles (3,390 kilometers) – about half the size of Earth’s.
Measuring Mars’ wobble also provided details about the shape of the core.
“RISE’s data indicate the core’s shape cannot be explained by its rotation alone,” said the paper’s second author, Attilio Rivoldini of the Royal Observatory of Belgium. “That shape requires regions of slightly higher or lower density buried deep within the mantle.”
While scientists will be mining InSight data for years to come, this study marks the final chapter for Banerdt’s role as the mission’s principal investigator. After 46 years with JPL, he retired on August 1.
Reference: “Spin state and deep interior structure of Mars from InSight radio tracking” by Sébastien Le Maistre, Attilio Rivoldini, Alfonso Caldiero, Marie Yseboodt, Rose-Marie Baland, Mikael Beuthe, Tim Van Hoolst, Véronique Dehant, William M. Folkner, Dustin Buccino, Daniel Kahan, Jean-Charles Marty, Daniele Antonangeli, James Badro, Mélanie Drilleau, Alex Konopliv, Marie-Julie Péters, Ana-Catalina Plesa, Henri Samuel, Nicola Tosi, Mark Wieczorek, Philippe Lognonné, Mark Panning, Suzanne Smrekar and W. Bruce Banerdt, 14 June 2023, Nature.
DOI: 10.1038/s41586-023-06150-0
More About the Mission
JPL managed InSight for NASA’s Science Mission Directorate. InSight was part of the Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supports spacecraft operations for the mission.
A number of European partners, including France’s Centre National d’Études Spatiales (CNES) and the German Aerospace Center (DLR), supported the InSight mission. CNES provided the Seismic Experiment for Interior Structure (SEIS) instrument to NASA, with the principal investigator at IPGP (Institut de Physique du Globe de Paris). Significant contributions for SEIS came from IPGP; the Max Planck Institute for Solar System Research (MPS) in Germany; the Swiss Federal Institute of Technology (ETH Zurich) in Switzerland; Imperial College London and Oxford University in the United Kingdom; and JPL. DLR provided the Heat Flow and Physical Properties Package (HP3) instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain’s Centro de Astrobiología (CAB) supplied the temperature and wind sensors.
That's what I remember they told us.
You'd think they'd have come up with a way to dust the panels, they have known about martian dust for decades.
Also, I thought Mars had no magnetic field to speak of. Wouldn't a 'sloshing molten core' generate one?
Depends on what is ‘molten’ and how big it is..................
“detecting a subtle acceleration and the planet’s wobble due to its molten core. “
Must be caused by globull warming on earth.
“a study analysing seismic wave data over the past 60 years by researchers at Peking University in China has concluded that the core’s rotation stopped around the year 2009, and then restarted in the opposite direction.”
Mars spinning faster but still not as fast as Joe Biden.
Anyway, for something to “slosh” there would need to be
an atmosphere inside the planet.
You can’t slosh a full bottle of water...
Bet its just another one of those scientific announcements that goes down the memory hole after someone redoes the calculations or assumptions...
And of course... It’s our fault.
I have my Slim Whitman records just in case.
Probably just trying to get farther away from earth.
Ack! Ack!
Is there ANYTHING that man made globull warming here on earth can’t do?
So the headline is wrong. Mars isn’t spinning faster, measurements are more accurate. Did I get that right? (Checking my speed reading comprehension)
/\
. urinalistic spin
on spin
to create missleading headline..
..its what they do by habit.
Sheila Jackson Lee wants to know if the American flag has been damaged.
All because of NASA SUV’s.
It depends on how big it is and what it is composed of. Earth is believed to have a solid iron-nickel inner core surrounded by a molten iron-nickel outer core. Mars could have a molten magma core.
Pretty interesting but these same scientists follow climate models on earth and are completely ignorant on what’s going on here.
Probably caused by my SUV, gas oven and charcoal grill.
If Mars continues to spin faster, all the Martians will fly off the planet by the end of the month. The recent influx of UFO sightings will decrease and we will probably have lost our only chance for positive interplanetary foreign relations with the red planet. We can’t pass up this chance to save the Martians.
This may sound improbable but using our extrapolations of Earth’s average monthly temperature over the past 6 months, global warming will push our temperatures to around 300 degrees a year from now. We have proposed a $50 Trillion Government program to fix the global warming problem. In the same spirit of intergalactic cooperation, we should propose a $100 Trillion Government program to fix the Mars rotation problem. If we don’t act now as an intergalactic community, a year from now, there may be no Martians left on Mars; all of them flung into the outer reaches of space.
Remember, it’s for the Martians.
I am so thankful we spent billion to find out about mars spinning faster, before -
…no wait.
Why do we need to know this?
Because if its spinning faster it means there are more days on Mars and we need to know how many days there are so we know how long it will take to get there!
At least that makes sense to the average government worker...
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