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Maybe Sulfur Dioxide, Not Carbon Dioxide, Kept Mars Warm

Article written: 20 Dec , 2007
Updated: 26 Dec , 2015
by

Try to walk on Mars today, and the planet will simultaneously freeze and suffocate you. Not to mention the minimal air pressure and relentless radiation from space. But billions of years ago, the Red Planet was much warmer and liquid water flowed on its surface. Warm temperatures on Earth are maintained by the carbon cycle, but maybe another greenhouse gas – sulfur dioxide (SO2) – maintained the temperatures on Mars.

This is the hypothesis put forward by Harvard and MIT researchers, published in the December 21st edition of the journal Science.

Over millions of years on Earth, our climate has been controlled by the carbon cycle. Carbon dioxide is released from volcanoes, and then chemical reactions with silicate rocks on the Earth’s surface remove it back out of the atmosphere and turn it into limestone.

There are vast deposits of limestone on Earth; evidence that the carbon cycle has been going on for eons. But planetary geologists haven’t found any limestone on Mars. If the planet was kept warm, the limestone should be there.

Perhaps another greenhouse gas, sulfur dioxide – also released in vast quantities from volcanoes – kept the atmosphere warm. On Earth, sulfur dioxide is removed quickly from the atmosphere, since it’s even more reactive with silicate rocks than carbon dioxide.

“The sulfur dioxide would essentially preempt the role of carbon dioxide in surface weathering reactions,” says Itay Halevy, the first author of the report. “The presence of even a small amount of sulfur dioxide in the atmosphere would contribute to the warmer climate, and also prevent limestone deposits from forming.”

So if this is true, sulfur minerals, and not limestone, should have formed in bodies of water. This may help to explain the surprising discovery the rovers have made that sulfur minerals are an abundant component of Martian soils.

With sulfur dioxide, the Martian oceans would have been much more acidic than Earth’s oceans. There might have been periods on Earth when our atmosphere was similar, and there could be similar periods when sulfur kept us warm too.

The similarities and differences of the two planets still have much to teach scientists.

Original Source: Harvard News Release


9 Responses

  1. Duane says

    Hmmm. Something to think about should we ever make it to the surface of the red planet. Wouldn’t any water found be close to battery acid in toxicity?

    Also, all that sulphur: Makes me wonder if Mars doesn’t smell too good. Better pack a few air fresheners….

  2. Asmita says

    the presence of sulphur in water indicates acidic environment when water flowed…this can also signify the presence of archaebacteria and the likes of it ( or rather their fossils) , if life ever flourished there.

    or maybe some super modified acidophile did survive!

  3. Kevin says

    If that be the case,did the poles shifting cause the loss atmosphere,maybe phoenisx will give us a few clues,of why Mars started living a dies a quick death.

  4. tmayes1999 says

    there is a good chance of sulphur metabolizing archea bacteria on mars.
    it could be source of methane gas
    underground there too.
    tim

  5. Pete says

    The entire universe is a mystery. We’d like to think we know but unfortunately we don’t. We need to send serious probes to Mars to research the poles and drill the surface for water and other signs of life to really speculate what is happening and has potentially happened in our Solar System , Galaxy and Universe.
    Even then, it is only pure speculation

  6. Win Scott says

    According to many planetary geologists, Mars dies several billion years ago when it’s magnetic field dissipated due to a cooling of it’s molten core, resulting in a slow-down of the processes which generate electrical currents within the core. With it’s magnetic field strength severely reduced, Mars’s atmosphere was bombarded by radiation and solor winds, and without the magnetosphere to deflect the radiaiton from space, eventually most of the atmosphere was ripped away, exposing the surface to even more radiation.

    Geologists on Earth report that our own magnetic field strength has nose-dived more than 10 percent in the last 100 years. But this appears to be too fast a change to indicate that the field is dying… more likely a precursor to a reversal of the magnetic poles, which has happened on an average of every 300,000 years, but hasn’t happened since we’ve been around. The last pole-reversal happened about 750,000 years ago. When the shift gets into full swing, our magnetic field may be reduced in strength by as much as 90 percent for a period of as much as 300 years until the poles stabilize. This could mean loss of atmosphere and greater exposure to radiation from space. However, life on Earth has survived many pole-reversals in the past, though the transition periods may have been responsible for mass extinctions.

  7. Steve says

    It sounds as though there won’t be much hope of eventually terraforming Mars. With an abundance of sulpher dioxide rather than carbon dioxide, and no surface water, there is little chance that any type of plant life could take hold. No plants means no oxygen, and the lack of magnetic field means that there is nothing to hold it in place anyway.

    So why are we going there? Wouldn’t it be more useful to learn how to mine the asteroid belt, for example?

  8. Jon says

    this is interesting

  9. André van Marweijk says

    Simplifying: Mass extintions on earth have in common that sulfur consuming organisms predominated for a “short” time period over carbon consuming organisms, with an ventual resurgence and predominance of “us” in the overall time. Maybe the reverse is appliable to Mars.
    The “god of War” is more suitable a name than we might have thought of.

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