Mars atmosphere well protected from the solar wind

Posted: December 10, 2017 by oldbrew in research, solar system dynamics
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Mars from NASA’s Hubble Space Telescope


The report says ‘a stronger solar wind mainly accelerates particles already escaping the planet’s gravity, but does not increase the ion escape rate’. That also raises the question of the thick Venusian atmosphere around another planet with no magnetism to speak of. Maybe some aspects of magnetosphere theory needs to be looked at again?

Despite the absence of a global Earth-like magnetic dipole, the Martian atmosphere is well protected from the effects of the solar wind on ion escape from the planet, reports Phys.org.

New research shows this using measurements from the Swedish particle instrument ASPERA-3 on the Mars Express spacecraft.

The results have recently been presented in a doctoral thesis by Robin Ramstad, Swedish Institute of Space Physics and Umeå University, Sweden.

Present-day Mars is a cold and dry planet with less than 1 percent of Earth’s atmospheric pressure at the surface.

However, many geological features indicate the planet had an active hydrological cycle about 3 to 4 billion years ago. An active hydrological cycle would have required a warmer climate in the planet’s early history and therefore a thicker atmosphere, one capable of creating a strong greenhouse effect.

A common hypothesis maintains that the solar wind over time has eroded the early Martian atmosphere, causing the greenhouse effect, and thus the hydrological cycle, to collapse. Unlike Earth, Mars has no global magnetic dipole, but the solar wind instead induces currents in the ionized upper atmosphere (the ionosphere), creating an induced magnetosphere.

“It has long been thought that this induced magnetosphere is insufficient to protect the Martian atmosphere,” says Robin Ramstad. “However, our measurements show something different.”

Continued here.

Comments
  1. E.M.Smith says:

    When the nuclear fuel in the core runs out, volcanic activity stops and with it the recycle of water of hydration to the seas and gasses to the air. Oceans end up in rock hydrates and atmospheres in oxides and carbonates.

    Mars died when the natural reactor died.

    Best estimates are that Earth (having more mass so more fuel) is going to run out in the next few millions of years to few hundred millions of years. But it’s a slow process…

  2. oldbrew says:

    Did a Big Bang lead to every planet and star having its own nuclear/magnetic ‘dynamo’?
    – – –
    The ionosphere is the ionized part of Earth’s upper atmosphere, from about 60 km (37 mi) to 1,000 km (620 mi) altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. [bold added]

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC58687/

    Maybe what is attributed to the magnetosphere, i.e. repulsion of the solar wind, is more to do with the ionosphere? That seems to be what happens on Mars (see post above), maybe Venus too.

    IOW the magnetosphere is an optional extra, or so these observations suggest.

  3. Oldbrew, there is much evidence that the supposed big bang was only a local explosion in our part of the universe. Unless you are a believer in creation and make the assumption (without proof) energy can not suddenly exist at some point source. There is considerable evidence that there was a large planet between earth and Jupiter and that Mars is a remnant of the explosion. A fragment of that explosion may have hit Venus to make it rotate in the opposite direction of the other planets. However, I am no expert but understand enough maths and engineering theory to determine that the common idea of a “big bang” which formed the entire universe can not have occurred.

  4. Bloke down the pub says:

    Just guessing, but wouldn’t the thicker atmosphere on Venus cf Mars be due at least in part to the stronger gravitational attraction on the former, stopping the molecules from escaping?

  5. oldbrew says:

    Bloke – maybe, but Mars is 4 times further away from the Sun than Venus.
    – – –
    It’s impact – or lack of – theory time again…

    Why doesn’t Venus have a magnetosphere?
    December 11, 2017

    For many reasons, Venus is sometimes referred to as “Earth’s twin” (or “sister planet,” depending on who you ask). Like Earth, it is terrestrial (i.e. rocky) in nature, composed of silicate minerals and metals that are differentiated between an iron-nickel core and silicate mantle and crust. But when it comes to their respective atmospheres and magnetic fields, our two planets could not be more different.

    For some time, astronomers have struggled to answer why Earth has a magnetic field (which allows it to retain a thick atmosphere) and Venus do not. According to a new study conducted by an international team of scientists, it may have something to do with a massive impact that occurred in the past. Since Venus appears to have never suffered such an impact, it never developed the dynamo needed to generate a magnetic field.

    Read more at: http://phys.org/news/2017-12-doesnt-venus-magnetosphere.html
    – – –
    Earth’s magnetosphere is supposed to protect its atmosphere from the solar wind, but Venus has a much thicker atmosphere despite no magnetosphere and being much closer to the source of the solar wind.

  6. Jim says:

    Interesting concept, that Mars died when it’s radioactive core ceased. Since we live near a variable star, would that have something to do with the loss of energy? Since the planet formed so far out from the star, would the chemical composition be different than earth? As in fewer large atoms? And could a younger star have had a larger output several million years ago? As the decay progresses, is that what we have to look out for?