[/caption]According to a new set of NASA computer simulations, solar storms and Coronal Mass Ejections (CMEs) can erode the lunar surface. Researchers speculate that not only can these phenomena erode the lunar surface, but could also be a cause of atmospheric loss for planets without a global magnetic field, such as Mars.
A team led by Rosemary Killen at NASA’s Goddard Space Flight Center, has written papers exploring different aspects of these phenomena and will appear in an issue of the Journal of Geophysical Research Planets. The team’s research was also presented earlier this week during the fall meeting of the American Geophysical Union.
What are CME’s? Corona Mass Ejections are intense outbursts of the Sun’s usually normal solar wind which consists of electrically charged particles (plasma). CME’s blow outward from the surface of the Sun at speeds in excess of 1.6 million kilometers per hour into space and can contain over a billion tons of plasma in a cloud larger than Earth.
Our Moon has the faintest traces of an atmosphere, which is technically referred to as an exosphere. The lack of any significant atmosphere, combined with the lack of a magnetic field, makes the lunar surface vulnerable to the effects of CME’s.
William Farrell, DREAM (Dynamic Response of the Environment at the Moon) team lead at NASA Goddard, remarked, “We found that when this massive cloud of plasma strikes the Moon, it acts like a sandblaster and easily removes volatile material from the surface. The model predicts 100 to 200 tons of lunar material – the equivalent of 10 dump truck loads – could be stripped off the lunar surface during the typical 2-day passage of a CME.”
While CME’s have been extensively studied, Farrell’s research is the first of its kind that attempts to predict the effects of a CME on the Moon. “Connecting various models together to mimic conditions during solar storms is a major goal of the DREAM project” added Farrell.
When intense heat or radiation is applied to a gas, the electrons can be removed, turning the atoms into ions. This process is referred to as “ionization”, and creates the fourth form of matter, known as plasma. Our Sun’s intense heat and radiation excites gaseous emissions, thus creating a solar wind plasma of charged particles. When plasma ions eject atoms from a surface, the process is called “sputtering”.
The lead author of the research paper Rosemary Killen described this phenomenon: “Sputtering is among the top five processes that create the Moon’s exosphere under normal solar conditions, but our model predicts that during a CME, it becomes the dominant method by far, with up to 50 times the yield of the other methods.”
In an effort to better test the team’s predictions, studies will be performed using NASA’s Lunar Atmosphere And Dust Environment Explorer (LADEE). Scheduled to launch in 2013 and orbit the Moon, the team is confident that the strong sputtering effect will send atoms from the lunar surface to LADEE’s orbital altitude (20 to 50 km).
Farrell also added, “This huge CME sputtering effect will make LADEE almost like a surface mineralogy explorer, not because LADEE is on the surface, but because during solar storms surface atoms are blasted up to LADEE.”
Affecting more than just our Moon, solar storms also affect Earth’s magnetic field and are the root cause of the Northern and Southern lights (aurorae). The effect solar storms have on Mars is a bit more significant, due in part to the Red Planet’s lack of a planet-wide magnetic field. It is widely theorized that this lack of a magnetic field allows the solar wind and CME’s to erode the martian atmosphere. In late 2013, NASA will launch the Mars Atmosphere and Volatile Evolution (MAVEN) mission. The goal of MAVEN is to orbit Mars and help researchers better understand how solar activity, including CMEs, affects the atmosphere of the red planet.
Learn more about the DREAM team at: http://ssed.gsfc.nasa.gov/dream/
If you’d like to know more about NASA’s Lunar efforts, visit: http://lunarscience.nasa.gov/
Source: NASA Solar System News
This concept is not new. One of the reasons Apollo 12 returned parts from Surveyor III was to determine what effect the solar wind had on those parts.
It is always a wonder to me that when mentioning loss of atmosphere, for planets without an magnetosphere, resulting from solar winds/storms, Mars is always mentioned, yet Venus is not. They should at least mention why they think Venus retains a thick atmosphere is face of an onslaught from a significantly closer sun, instead of simply pointing to Mars as an example of the effects of the sun.
Matt,
My understanding (albeit planetary atmospheres aren’t my specialty) is that Venus is losing atmosphere to these effects as well. It’s thought that Venus undergoes periods of catastrophic volcanic activity which would throw tremendous amounts of noxious gases into its atmosphere. Most of what is being lost to space is Oxygen and Hydrogen ( from the disassociation of water molecules), so the heavier compounds like CO2 stay put.
Interestingly in this context, the consensus opinion on Venus crustal turnover recently faced observations hinting on that it may be wrong:
“Today’s announcement concerns a paper published by Sue Smrekar and seven coauthors in Science: “Recent Hot-Spot Volcanism on Venus from VIRTIS Emissivity Data.” Smrekar et al. outline evidence suggesting that lava flows around several large Venusian volcanoes are fresh and unweathered, implying that they are no older than 2.5 million years, and possibly are younger than 250,000 years old. That is young enough to suggest strongly that Venus is active right now.
The data that they are using come from the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument on Venus Express. […]
The conclusion to be drawn from the present paper is that Imdr Regio is a currently active hot spot, producing recent flows at Idunn Mons. There are other Venusian volcanoes that may be currently active as well, including Innini and Hathor Montes in Dione Regio, and several volcanoes including Mielikki Mons within Themis Regio. […]
It’s funny how debates in geology always seem to come down to a fight between catastrophists and uniformitarians. It’s no different on Venus. There’s one camp of people who say that all of Venus suffered a global catastrophe at the same time, leading to different styles of volcanism and tectonism that evolved fairly quickly over time from one style of geologic activity to another, ending a few hundred million years ago. And there’s another camp of people who argue that this point of view is ludicrous, that Venusian geology is, like Earth’s, local, with different processes operating in different places at different times, and that the whole planet has been geologically active, continuously renewing the crust, leading to an average surface age of a few hundred million years but an actual age that varies from place to place.
That’s why people are so interested in looking for active volcanism on Venus. If someone discovered very recent or active volcanism on Venus, it would be a major win for the uniformitarian camp (not to mention the fact that it would be really cool to add Venus to the list of planets we know to be geologically active today).”
My take is that Venus now looks a lot more like Earth and Mars, having active mantle hot spots and recent or ongoing volcanism. The difference is more like between a single plate and many plates, not between a stagnant lid with turnovers and plates.
Not to forget that Venus has much more mass compared to Mars making it a lot easier to keep all that gases around. Also the atmosphere of Venus contains a lot of very heavy molecules (CO2, for example), which can be kept much easier than lightweight molecules like H2.
I have a question
It is known that on our planet are investments pole N and S, as shown in the stratigraphic record submarines.
Lel timely period during which the investment is made. Is the Earth can be unprotected?
Is there any coincidence with mass extinction species with these periods?
Jordi,
Take a look at an article from last week. Should answer your question. Also, I don’t think you’re using the word “investments” correctly but it’s obvious English is not your first language. I think the word you’re looking for is “inversions”.
http://www.universetoday.com/91561/earths-magnetic-pole-reversal-dont-flip-out/
Oh, Thanks!
My Primary language is Spanish.
Thanks for this article
What is interesting to me [once a researcher in reactive sputtering] is that it is the heavier ions of CMEs (helium) that enhance sputtering.
If you think about the energy transfer between colliding particles m1 & m2, it goes as m1*m2 and hence the maximum as m = m1 = m2.
Speaking of which, some mistakes here and in the NASA source:
No, sputtering is but one possible mechanism.
Sputtering is the process whereby collision cascades knocks out material, by momentum transfer (low velocities) or heat assisted momentum transfer (high velocities).
Other mechanisms is thermally induced absorption, surface chemical reactions making gases et cetera.
If you nitpick the definition on a micro scale [micro nits? =D], technically no non-relativistic ions sputter a solid target. Ions will be neutralized by electrons jumping out of the surface before they hit. This also means the incoming flow is not “plasma” at the time.
This gives the impression that high velocity means high sputter yield. (Yield := number of sputtered atoms/incoming ion.)
This is not always the case.
– Physical sputtering maximizes for ions of the same kind as the sputter target, this is why the CME is more efficient.
– Higher energy ions burrow deeper, so the collisional cascade has longer distance and more volume to disperse before the surface release sputter atoms. Generally you can see a local maximum in the yield at low velocities before it increases again.
Of course the yield tends to go up with velocity. And the ion flow as well, adding to the increase in sputter flow.
Am always curious about the actual content of the solar wind. Does it change over time? That is to say spectral lines of one element becoming prominent due to solar core evolution.
There’s a 30% chance of increased ionized Hydrogen in the solar wind today… with wide bands of calcium and oxygen present as the solar jet stream heads south…