Question about magnetic fields, solar winds, and atmospheres

GbreadMan · Nov 28, 2008

Hello,  new here, but had a question that's bugging me.Scientists believe Mars lost it's atmosphere because it has a very weak, intermittent magnetic field.  This caused the solar wind to blast most of the atmosphere off into space.In this logic, Earth has a more robust atmosphere (and biosphere) because of our magnetic field.So my question is:  Why isn't Venus just like Mars?   Venus has no measurable magnetic field, gets bombarded even more than the Earth or Mars by the solar wind, yet has a robust atmosphere 93 times as dense as the earth.Thanks,Dan  <div class="Discussion_UserSignature"> </div>

origin · Nov 29, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hello,  new here, but had a question that's bugging me.Scientists believe Mars lost it's atmosphere because it has a very weak, intermittent magnetic field.  This caused the solar wind to blast most of the atmosphere off into space.In this logic, Earth has a more robust atmosphere (and biosphere) because of our magnetic field.So my question is:  Why isn't Venus just like Mars?   Venus has no measurable magnetic field, gets bombarded even more than the Earth or Mars by the solar wind, yet has a robust atmosphere 93 times as dense as the earth.Thanks,Dan  Posted by GbreadMan</DIV> I think that there ar multiple reasons that a planet has an atmosphere.  Gravity is a major reason that a planet has an atmosphere.  I think that mars has a minimal atmosphere because of it's size and low magnetic field.Venus is losing it's atmosphere due to the solar winds but it's large size means it is losing it much more slowly than mars. <div class="Discussion_UserSignature"> </div>

3488 · Nov 29, 2008

Welcome to SDC Dan.  Replying to: <DIV CLASS='Discussion_PostQuote'>I think that there ar multiple reasons that a planet has an atmosphere.  Gravity is a major reason that a planet has an atmosphere.  I think that mars has a minimal atmosphere because of it's size and low magnetic field.Venus is losing it's atmosphere due to the solar winds but it's large size means it is losing it much more slowly than mars. Posted by origin</DIV>origin has is pretty well spot on.Also Venus appears to have active volcanoes which also replenish said atmosphere off setting the slow loss from the Solar Wind. Mars's volcanoes appear dead & as you say, Mars is far too small & not enough mass to retain a dense atmosphere at that distance from the Sun, despite receiving only about a fifth of the solar energy Venus does. With Mars it will get even worse, with the extreme long term future of Mars losing all of it's ice, low temperature volatiles & atmosphere totally & becoming a truly atmosphere less world like the Moon or Mercury.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

why06 · Nov 29, 2008

Just a random question:With respect to Earth how large are Mars and Venus? <div class="Discussion_UserSignature"> <div>________________________________________ </div><div><ul><li>your move...</li></ul></div> </div>

MeteorWayne · Nov 29, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Just a random question:With respect to Earth how large are Mars and Venus? Posted by why06</DIV> For the purpose of this discussion, the more important question is how massive are they compared to earth.Venus has 0.815 the mass of earth, Mars 0.107, Mercury 0.055, Pluto and Eris 0.003 <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

why06 · Nov 29, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>For the purpose of this discussion, the more important question is how massive are they compared to earth.Venus has 0.815 the mass of earth, Mars 0.107, Mercury 0.055, Pluto and Eris 0.003 Posted by MeteorWayne</DIV>thanks that really puts things in perspective. <div class="Discussion_UserSignature"> <div>________________________________________ </div><div><ul><li>your move...</li></ul></div> </div>

MeteorWayne · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>thanks that really puts things in perspective. Posted by why06</DIV> U R Welcome

<div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

vogon13 · Nov 30, 2008

Earth has a tremendous amount of CO2 locked up as a solid in the form of carbonate rocks.  Should it all be released, YOIKS !!    <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

a_lost_packet_ · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Just a random question:With respect to Earth how large are Mars and Venus? Posted by why06</DIV>This is a pretty good illustrative pic:  <img src="http://sitelife.space.com/ver1.0/Content/images/store/4/8/44bdd1d8-d02a-493d-b875-80e5932df139.Medium.gif" alt="" />  http://www.nineplanets.org/overview.html <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

GbreadMan · Nov 30, 2008

Thanks for the replies,  I guess the stellar wind works over a very long period of time.  Being smaller and "cooler" doesn't help Mars' situation, either.   One extra question.   Would the magnetic field (on mars or venus or any planet with a molen core) become greater if the planet spun at a faster rate?  Mars is smaller, and its rotation is similar (almost identical) to the Earth's...but due to it's smaller size, would a faster rotation trigger a more active magnetic field? Thanks,Dan <div class="Discussion_UserSignature"> </div>

MeteorWayne · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Thanks for the replies,  I guess the stellar wind works over a very long period of time.  Being smaller and "cooler" doesn't help Mars' situation, either.   One extra question.   Would the magnetic field (on mars or venus or any planet with a molen core) become greater if the planet spun at a faster rate?  Mars is smaller, and its rotation is similar (almost identical) to the Earth's...but due to it's smaller size, would a faster rotation trigger a more active magnetic field? Thanks,Dan Posted by GbreadMan</DIV> Since Mars no longer has a significant liquid core, there's no means to generate a dynamo which creates the magnetic field. So currently (haha) a faster spin rate would make no difference. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Dec 2, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Since Mars no longer has a significant liquid core, there's no means to generate a dynamo which creates the magnetic field. So currently (haha) a faster spin rate would make no difference. Posted by MeteorWayne</DIV>That's very true Wayne.Also Mercury & Jupiter's moon Ganymede both have appreciable internally driven magnetospheres, weak by Earth's standards, but still appreciable (not fossil fields or induced secondary fields like Europa & Callisto, induced by Jupiter's own field) & they rotate far more slowly than Mars, approx 59 days & 7 days respectively.Ganymede & almost certainly Mercury too, as well as Earth are the only planetary bodies known to have dual layered cores (outer & inner). Even Venus appears to lack this, despite the density & mass of Venus only being slightly inferior to Earth's. Mars also lacks this & Mars's core certainly does not convect. Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

Mee_n_Mac · Dec 2, 2008

FWIW : I thought the OP might find this interesting ....From http://www.sciencedaily.com/releases/2008/11/081123142222.htmScienceDaily (Nov. 29, 2008) — Researchers have found new evidence that the atmosphere of Mars is being stripped away by solar wind. It's not a gently continuous erosion, but rather a ripping process in which chunks of Martian air detach themselves from the planet and tumble into deep space. This surprising mechanism could help solve a longstanding mystery about the Red Planet."It helps explain why Mars has so little air," says David Brain of UC Berkeley, who presented the findings at the 2008 Huntsville Plasma Workshop on October 27th.Billions of years ago, Mars had a lot more air than it does today. (Note: Martian "air" is primarily carbon dioxide, not the nitrogen-oxygen mix we breathe on Earth.) Ancient martian lake-beds and river channels tell the tale of a planet covered by abundant water and wrapped in an atmosphere thick enough to prevent that water from evaporating into space.Some researchers believe the atmosphere of Mars was once as thick as Earth's. Today, however, all those lakes and rivers are dry and the atmospheric pressure on Mars is only 1% that of Earth at sea-level. A cup of water placed almost anywhere on the Martian surface would quickly and violently boil away—a result of the super-low air pressure.So where did the air go? Researchers entertain several possibilities: An asteroid hitting Mars long ago might have blown away a portion of the planet's atmosphere in a single violent upheaval. Or the loss might have been slow and gradual, the result of billions of years of relentless "sand-blasting" by solar wind particles. Or both mechanisms could be at work.Brain has uncovered a new possibility--a daily ripping process intermediate between the great cataclysm and slow erosion models. The evidence comes from NASA's now-retired Mars Global Surveyor (MGS) spacecraft.In 1998, MGS discovered that Mars has a very strange magnetic field. Instead of a global bubble, like Earth's, the Martian field is in the form of magnetic umbrellas that sprout out of the ground and reach beyond the top of Mars' atmosphere. These umbrellas number in the dozens and they cover about 40% of the planet’s surface, mainly in the southern hemisphere. More at the URL above. <div class="Discussion_UserSignature"> -----------------------------------------------------Ask not what your Forum Software can do do on you,Ask it to, please for the love of all that's Holy, STOP ! </div>

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Question about magnetic fields, solar winds, and atmospheres

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