One of the primary drivers for the distinct lack of a Martian atmosphere is believed to be the loss of atmospheric molecules that are stripped away by the passing solar wind. A strong planetary magnetic field would divert the solar wind around the planet and protect the Martian atmosphere. The MAVEN spacecraft confirmed this is happening, and some interesting ideas have been floated to mitigate the effect.
A recent paper published in JGR: Space Physics used Magnetohydrodynamic (MHD) models to investigate the magnitude of the effect on atmospheric retention that a magnetic field would have on Mars and found a very interesting result. Their models confirmed that the rate of atmospheric loss was six times higher for a planet with no magnetic field compared to a planet with a strong magnetic field; however, they found the highest rate of atmospheric loss was actually when there was a weak magnetic field.
But the highest rate of atmospheric ion loss was with a weak magnetic field—6 times faster than with no magnetic field at all. The team found the reason was the magnetic field lines, which guide the motion of charged particles, were easily blown back by the solar wind, creating a path for these ions to escape into space above Mars's nightside. This means that instead of providing a small measure of protection, Mars's remnant magnetic field could actually have sped the planet's transformation into the cold, barren world it is today.
Research Paper: Sakata, et al., Effects of an Intrinsic Magnetic Field on Ion Loss From Ancient Mars Based on Multispecies MHD Simulations, Journal of Geophysical Research: Space Physics, https://doi.org/10.1029/2019JA026945, 2020
Author's Plain Language Summary:
It has been suggested that ancient Mars had an atmosphere thick enough to sustain liquid water on its surface, while present Mars only has a thin atmosphere. Ion loss to space is one of the important processes for the removal of the atmosphere because a younger Mars would have been exposed to much stronger solar activity. Over 4 Ga, Mars had an intrinsic magnetic field like that of the Earth. The existence of an intrinsic magnetic field changes the electromagnetic environment around the planet and affects the ion loss. We investigate the ion loss from Mars at approximately 4.5 Ga, assuming both the strong solar conditions and the existence of an intrinsic magnetic field using numerical simulations. The results show that the existence of the weak dipole field increases the loss of molecular ions such as O2+ and CO2+. Contrary to the weak intrinsic magnetic field, however, a strong intrinsic magnetic field substantially decreases the loss of molecular ions. The ion loss processes are also affected by the intrinsic magnetic field. These effects of the intrinsic magnetic field are less pronounced for O+ loss because of the extended O+ corona.
Related Stories
NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission has been gathering information on Mars' upper atmosphere, ionosphere, and solar and solar-wind interactions since its orbit insertion in September 2014. On November 5th the first MAVEN results were published in a special issue of Geophysical Research Letters . The issue contains over 40 articles investigating measurements of the overall geometry and variability of the Martian magnetosphere, upper atmosphere, and ionosphere and their responses to interplanetary coronal mass ejections and solar energetic particle influxes, with the highlights covered in the introductory article. NASA also held a news briefing discussing the results.
One of the many results presented was the identification of the process that transitioned the Martian climate from warm and wet to cold and arid. MAVEN has measured the rate at which the solar wind is stripping the Martian atmosphere of gas:
"Mars appears to have had a thick atmosphere warm enough to support liquid water which is a key ingredient and medium for life as we currently know it," said John Grunsfeld, astronaut and associate administrator for the NASA Science Mission Directorate in Washington. "Understanding what happened to the Mars atmosphere will inform our knowledge of the dynamics and evolution of any planetary atmosphere. Learning what can cause changes to a planet's environment from one that could host microbes at the surface to one that doesn't is important to know, and is a key question that is being addressed in NASA's journey to Mars."
https://m.phys.org/news/2017-03-nasa-magnetic-shield-mars-atmosphere.html
In essence, they suggested that by positioning a magnetic dipole shield at the Mars L1 Lagrange Point, an artificial magnetosphere could be formed that would encompass the entire planet, thus shielding it from solar wind and radiation.
[...] In addition, the positioning of this magnetic shield would ensure that the two regions where most of Mars' atmosphere is lost would be shielded
[...] As a result, Mars atmosphere would naturally thicken over time, which lead to many new possibilities for human exploration and colonization. According to Green and his colleagues, these would include an average increase of about 4 °C (~7 °F), which would be enough to melt the carbon dioxide ice in the northern polar ice cap. This would trigger a greenhouse effect, warming the atmosphere further and causing the water ice in the polar caps to melt.
Pretty SF but I enjoyed the article.
NASA's MAVEN spacecraft has found that solar wind and radiation are responsible for stripping away most of the Martian atmosphere, and that the rate of atmosphere loss was higher earlier in the history of the solar system:
Solar wind and radiation are responsible for stripping the Martian atmosphere, transforming Mars from a planet that could have supported life billions of years ago into a frigid desert world, according to new results from NASA's MAVEN spacecraft. "We've determined that most of the gas ever present in the Mars atmosphere has been lost to space," said Bruce Jakosky, principal investigator for the Mars Atmosphere and Volatile Evolution Mission (MAVEN), University of Colorado in Boulder. The team made this determination from the latest results, which reveal that about 65 percent of the argon that was ever in the atmosphere has been lost to space. Jakosky is lead author of a paper on this research to be published in Science on Friday, March 31.
In 2015, MAVEN team members previously announced results that showed atmospheric gas is being lost to space today and described how atmosphere is stripped away. The present analysis uses measurements of today's atmosphere for the first estimate of how much gas was lost through time. Liquid water, essential for life, is not stable on Mars' surface today because the atmosphere is too cold and thin to support it. However, evidence such as features resembling dry riverbeds and minerals that only form in the presence of liquid water indicates the ancient Martian climate was much different – warm enough for water to flow on the surface for extended periods.
It's time to stop it.
YouTube video attached to the article, and infographic. Also at University of Colorado Boulder.
Mars' atmospheric history derived from upper-atmosphere measurements of 38Ar/36Ar (DOI: 10.1126/science.aai7721) (DX)
(Score: 0) by Anonymous Coward on Saturday April 04 2020, @02:09AM (3 children)
It had to be said.
(Score: 2) by crb3 on Saturday April 04 2020, @02:19AM (1 child)
They're talking about solar wind, not wind from Uranus.
(Score: 0) by Anonymous Coward on Saturday April 04 2020, @03:59AM
HEW BLEW MY COVAAAARRRR!
PS: penis
(Score: 2) by DannyB on Saturday April 04 2020, @07:58PM
I think Elon is wrong to set his sights on Mars.
I hear that Jupiter is much larger than Mars. This would make possible much larger scale agriculture.
The lower I set my standards the more accomplishments I have.
(Score: -1, Offtopic) by Anonymous Coward on Saturday April 04 2020, @03:11AM
CRZH FA2020 CRZH JFZOLPLCQ CRZH DXQBP ALKQ QXHB QEB JXOH
(Score: 2) by deimtee on Saturday April 04 2020, @05:50AM (4 children)
Put superconductors around the equator and run a total of a million amps through them.
Compared to the rest of terraforming it's a pretty small project.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 0) by Anonymous Coward on Saturday April 04 2020, @09:01AM
> Put superconductors
Woah - for a minute there I was worried.
I read that as PET SUPERCONDUCTORS.
(Score: 2) by DannyB on Saturday April 04 2020, @07:59PM (2 children)
These superconductors could be part of a new, larger super collider project.
The lower I set my standards the more accomplishments I have.
(Score: 0) by Anonymous Coward on Monday April 06 2020, @05:26PM (1 child)
Do supercoliders run constantly? Would a pulsating magnetic field work at all?
(Score: 2) by deimtee on Tuesday April 07 2020, @03:57AM
Not usually, but the electromagnets probably stay on. DannyB was being funny. Combining an artificial planetary magnetic field with a supercollider would be more difficult than just building the two separate things.
It would work in proportion to the time it was pulsed on. The main reason for superconductors was that once the current and magnetic field were established it would need very little energy to maintain. Pulsing would require a continuous large power input.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 0) by Anonymous Coward on Sunday April 05 2020, @12:15AM
That explains why you need an artificial moon like Earth's to protect the planet. Then put in an atmosphere by hitting the planet with meteors that contain the needed gases in solid form, and meteors that contain solid ice to make the oceans. Then add life to it and watch it take over the planet and destroy it like a virus. The jews already know this because they are from another humanoid race from another place.