Magnetic field at Martian surface ten times stronger than expected

Posted: February 25, 2020 by oldbrew in atmosphere, Electro-magnetism, exploration, solar system dynamics
Tags: ,

Mars from NASA’s Hubble Space Telescope


Tales of the unexpected on Mars: ‘Day-night fluctuations and things that pulse in the dark’, and other mysteries. What’s unique to Mars?

New data gleaned from the magnetic sensor aboard NASA’s InSight spacecraft is offering an unprecedented close-up of magnetic fields on Mars, says Phys.org.

“One of the big unknowns from previous satellite missions was what the magnetization looked like over small areas,” said lead author Catherine Johnson, a professor at the University of British Columbia and senior scientist at the Planetary Science Institute.

“By placing the first magnetic sensor at the surface, we have gained valuable new clues about the interior structure and upper atmosphere of Mars that will help us understand how it – and other planets like it – formed.”

Zooming in on magnetic fields

Before the InSight mission, the best estimates of Martian magnetic fields came from satellites orbiting high above the planet, and were averaged over large distances of more than 150 kilometres.

“The ground-level data give us a much more sensitive picture of magnetization over smaller areas, and where it’s coming from,” said Johnson. “In addition to showing that the magnetic field at the landing site was ten times stronger than the satellites anticipated, the data implied it was coming from nearby sources.”

Scientists have known that Mars had an ancient global magnetic field billions of years ago that magnetized rocks on the planet, before mysteriously switching off. Because most rocks at the surface are too young to have been magnetized by this ancient field, the team thinks it must be coming from deeper underground.

“We think it’s coming from much older rocks that are buried anywhere from a couple hundred feet to ten kilometres below ground,” said Johnson. “We wouldn’t have been able to deduce this without the magnetic data and the geology and seismic information InSight has provided.”

The team hopes that by combining these InSight results with satellite magnetic data and future studies of Martian rocks, they can identify exactly which rocks carry the magnetization and how old they are.

Day-night fluctuations and things that pulse in the dark

The magnetic sensor has also provided new clues about phenomena that occur high in the upper atmosphere and the space environment around Mars.

Just like Earth, Mars is exposed to solar wind, which is a stream of charged particles from the Sun that carries an interplanetary magnetic field (IMF) with it, and can cause disturbances like solar storms. But because Mars lacks a global magnetic field, it is less protected from solar weather.

“Because all of our previous observations of Mars have been from the top of its atmosphere or even higher altitudes, we didn’t know whether disturbances in solar wind would propagate to the surface,” said Johnson. “That’s an important thing to understand for future astronaut missions to Mars.”

The sensor captured fluctuations in the magnetic field between day and night and short, mysterious pulsations around midnight, confirming that events in and above the upper atmosphere can be detected at the surface.

The team believe that the day-night fluctuations arise from a combination of how the solar wind and IMF drape around the planet, and solar radiation charging the upper atmosphere and producing electrical currents, which in turn generate magnetic fields.

“What we’re getting is an indirect picture of the atmospheric properties of Mars – how charged it becomes and what currents are in the upper atmosphere,” said co-author Anna Mittelholz, a postdoctoral fellow at the University of British Columbia.

And the mysterious pulsations that mostly appear at midnight and last only a few minutes?

“We think these pulses are also related to the solar wind interaction with Mars, but we don’t yet know exactly what causes them,” said Johnson. “Whenever you get to make measurements for the first time, you find surprises and this is one of our ‘magnetic’ surprises.”

Full report here.

Comments
  1. oldbrew says:

    Another report today:
    ‘Marsquakes caused by tectonic activity, NASA’s InSight probe confirms’

    InSight has detected more than 450 quakes on Mars since it arrived in November 2018.
    . . .
    Dr Bruce Banerdt, InSight principal investigator and lead author on one of the studies, said: “We finally have, for the first time, established that Mars is a seismically active planet.”

    https://www.sciencefocus.com/news/marsquakes-caused-by-tectonic-activity-nasas-insight-probe-confirms/
    – – –
    Tectonics of Mars

    Today, Mars is believed to be largely tectonically inactive.
    https://en.wikipedia.org/wiki/Tectonics_of_Mars

    Not with 450 earthquakes ’caused by tectonic activity’ since late 2018 April 2019?

  2. Damian says:

    Tectonic plate theory is nonsense. We don’t see it anywhere else, even where we do detect seismic activity, and it doesn’t fit observations on Earth.

  3. Damian says:

    Titan has an elliptical orbit which takes it out of Saturn’s magnetosphere at apoapsis. Titan has no magnetic field whilst within Saturn’s magnetosphere but has a magnetic field once it leaves Saturn’s electromagnetic environment and is within the Sun’s.

  4. Dodgy Geezer says:

    “We think it’s coming from much older rocks that are buried anywhere from a couple hundred feet to ten kilometres below ground,”

    This will bring out the activists, shouting:”No drilling on Mars!”…

  5. oldbrew says:

    Science Focus also says:
    The first so-called “Marsquake” was recorded by InSight’s onboard sensors in April 2019. Since then, it has detected more than 450 quivers, much smaller than anything that would be felt on Earth.

    So marsquakes are nothing like earthquakes, at least in terms of magnitude.

  6. Damian says:

    “We think it’s coming from much older rocks that are buried anywhere from a couple hundred feet to ten kilometres below ground,”
    Every time there is some sort of challenge to consensus science the solution is found somewhere that cannot be observed.

  7. Paul Vaughan says:

    “Whenever you get to make measurements for the first time, you find surprises and this is one of our ‘magnetic’ surprises.”

    Perfect 4 cynicism: Ban first-time measurements.

  8. oldbrew says:

    And the mysterious pulsations that mostly appear at midnight and last only a few minutes?

    Midnight depends on where the observer (sensor) is.

  9. oldbrew says:

    Seismic Activity on Mars Resembles that Found in the Swabian Jura
    February 27, 2020

    Twenty of these marsquakes had a magnitude of between three and four. Quakes of this intensity correspond to weak seismic activity of the kind that occurs repeatedly on Earth in the middle of continental plates, for example in Germany on the southern edge of the Swabian Jura hills.

    http://www.parabolicarc.com/2020/02/27/seismic-activity-on-mars-resembles-that-found-in-the-swabian-jura/

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