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Messenger Data Says Mercury's Magnetic Past Goes Back Billions of Years

Posted by timothy on from the do-you-have-receipts? dept.

Space.com notes a study published in the May 7th issue of Science (abstract) which concludes not only that Mercury has a magnetic history dating back billions of years, but also that the strength of that field means that it once rivaled Earth's own magnetic field, though it is now "about 100 times weaker." The source of this conclusion is data gathered prior to the crash of NASA's Messenger probe into Mercury's surface on April 30 of this year. Says the story: The researchers analyzed magnetic data collected by MESSENGER in the fall of 2014 and 2015, when the spacecraft flew incredibly close to the planet's surface, at altitudes as low as 9 miles (15 kilometers). In contrast, the lowest that MESSENGER flew in previous years was between 125 and 250 miles (200 and 400 km). ... The scientists detected magnetized rocks in a part of Mercury's crust that, due to the presence of many craters from cosmic impacts, appears to be quite ancient. The researchers suggest the rocks were once magnetized by the planet's magnetic field, and based on the age and amount of the magnetized rocks, as well as how strongly they were magnetized, the investigators deduced that Mercury's magnetic field has persisted for 3.8 billion years.

26 comments

  1. The core by Anonymous Coward · · Score: 0

    it stopped spinning.

    1. Re:The core by antiperimetaparalogo · · Score: 1

      it stopped spinning.

      Yes, based on the dynamo theory, the core stoped spinning, so no generation of magnetic field.

      --
      Antisthenes: "Wisdom begins by examining the words/names." - excuse my English, i am (slightly...) better with my Greek!
    2. Re:The core by Tablizer · · Score: 2

      it stopped spinning.

      Quick, elect it!

      --
      Table-ized A.I.
    3. Re:The core by PPH · · Score: 1

      Possibly due to tidal locking

      --
      Have gnu, will travel.
    4. Re:The core by antiperimetaparalogo · · Score: 1

      Hmmm... i think your comment is more correctly/accurately related to Mercury's generation (or not) of magnetic field than mine!

      --
      Antisthenes: "Wisdom begins by examining the words/names." - excuse my English, i am (slightly...) better with my Greek!
    5. Re:The core by X0563511 · · Score: 1

      That close to the sun, however... isn't it possible for the core to have some convective motion?

      --
      For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
    6. Re:The core by PPH · · Score: 1

      convective motion

      Yes. But that might not be moving in the correct direction to produce a magnetic field external to the core. Fleming's right hand rule and all that.

      --
      Have gnu, will travel.
    7. Re:The core by Anonymous Coward · · Score: 0

      Convection is an inherently 2D motion in normal fluids, so it can't avoid interacting with the magnetic field due to being aligned to the field line. However, Cowling's theorem prevents a dynamo from being axisymmetric, and requires 3D effects like differential rotation or Coriolis effect to generate a sizable magnetic field. Mercury's rotation is too slow and rigid to support those options.

  2. Significance? by Anonymous Coward · · Score: 0

    What does this tell us about Mercury other than the fact that it has and has had a magnetic field?

    1. Re:Significance? by Anonymous Coward · · Score: 0

      > What does this tell us about Mercury other than the fact that it has and has had a magnetic field?

      Since it is now a 100 times weaker, we can only suppose some planetary scale event did away with the magnetism. But what could it be? Now it's time for some theories to try to explain and be proved or refuted.

      Like e.g. magnets are nullified by heat. Maybe the entire planet has gone through some kind of artificially induced climate warming? Nah, that is impossible.

    2. Re: Significance? by Anonymous Coward · · Score: 0

      Or that, you know, it was created with a magnetic core around the time the sun formed, and since then it has been eroded due to close proximity to the sun?

    3. Re:Significance? by Anonymous Coward · · Score: 0

      we can only suppose some planetary scale event did away with the magnetism.

      And your reasoning for this is...?

  3. Someone installed systemd. by Hognoxious · · Score: 1

    They tried to restart the core-spin service, but something was in an inconsistent state and they couldn't read the stupid binary logs to find out what.

    --
    Confucius say, "Find worm in apple - bad. Find half a worm - worse."
    1. Re:Someone installed systemd. by Anonymous Coward · · Score: 0

      I hear it's fixed in Kit Kat, but I doubt it'll be getting the update.

  4. OP by Anonymous Coward · · Score: 0

    I want to care.... I really do. Someone please tell me why I should.

  5. Have you stopped to considered the written history by Anonymous Coward · · Score: 0

    I see no such notice in this Bible. Maybe YOUR Bible published by Satan does but I assure you mine does not!

  6. heh. by Black+Parrot · · Score: 4, Funny

    n the fall of 2014 and 2015, when the spacecraft flew incredibly close to the planet's surface, at altitudes as low as 9 miles (15 kilometers)

    I do believe it flew a lot closer than that in 2015.

    --
    Sheesh, evil *and* a jerk. -- Jade
    1. Re:heh. by Anonymous Coward · · Score: 0

      that was because it switched to another type of flying called falling.

    2. Re:heh. by Anonymous Coward · · Score: 0

      It threw itself deliberately at Mercury and didn't miss.

    3. Re:heh. by Anonymous Coward · · Score: 0

      That's not flying... That's falling, with style.

  7. global warming / climate change by Anonymous Coward · · Score: 0

    Thats why.

  8. They omitted the best part by Anonymous Coward · · Score: 0

    [...] the spacecraft flew incredibly close to the planet's surface, at altitudes as low as 9 miles (15 kilometers), causing Mercury to travel back in time 3.8 billion years like in Superman : The Movie (1978)

  9. Troll fail by Anonymous Coward · · Score: 0

    Just give it up, you fail.

  10. Solar wind interactions by Gary+Perkins · · Score: 2

    If I remember correctly, auroras here on Earth are produced by charged particles being funneled into the atmosphere by our magnetic field, and the lights are produced by ionization of various elements in the process. However, I can't help but wonder if there would be any observable effects of a strong planetary magnetic field so close to the sun? In other words, would Mercury appear any different than it does now in our sky, viewed either against black space or as it traverses across the Sun?

  11. Good thing. by nospam007 · · Score: 1

    So when can we expect mercury harddisks?

    1. Re:Good thing. by vandamme · · Score: 1

      They're not popular, because you have to keep them below -40 degrees (F or C) or they melt.