"Unprecedented" --Wednesday NASA Live Streams News Event on Mars Dust Storm Combined Size of North America & Russia
"Youngest in the Milky Way" --Three New Planets Observed Around Infant Star

Violent Solar Winds Create Exospheres of Shattered Rock Around the Moon & Mercury


832_24746_802303

The planets and moons of our solar system are continuously being bombarded by particles hurled away from the sun. On Earth this has hardly any effect, apart from the fascinating northern lights, because the dense atmosphere and the magnetic field of the Earth protect us from these solar wind particles. But on the Moon or on Mercury things are different: There, the uppermost layer of rock is gradually eroded by the impact of sun particles.

New results of the TU Wien now show that previous models of this process are incomplete. The effects of solar wind bombardment are in some cases much more drastic than previously thought. These findings are important for the ESA mission BepiColombo, Europe's first Mercury mission. The results have now been published in the planetology journal Icarus.

 

"The solar wind consists of charged particles - mainly hydrogen and helium ions, but heavier atoms up to iron also play a role," explains Prof. Friedrich Aumayr from the Institute of Applied Physics at TU Wien. These particles hit the surface rocks at a speed of 400 to 800 km per second and the impact can eject numerous other atoms. These particles can rise high before they fall back to the surface, creating an "exosphere" around the Moon or Mercury - an extremely thin atmosphere of atoms sputtered from the surface rocks by solar wind bombardment.

This exosphere is of great interest for space research because its composition allows scientists to deduce the chemical composition of the rock surface - and it is much easier to analyse the exosphere than to land a spacecraft on the surface. In October 2018, ESA will send the BepiColombo probe to Mercury, which is to obtain information about the geological and chemical properties of Mercury from the composition of the exosphere.

However, this requires a precise understanding of the effects of the solar wind on the rock surfaces, and this is precisely where decisive gaps in knowledge still exist. Therefore, the TU Wien investigated the effect of ion bombardment on wollastonite, a typical moon rock. "Up to now it was assumed that the kinetic energy of the fast particles is primarily responsible for atomization of the rock surface," says Paul Szabo, PhD student in Friedrich Aumayr's team and first author of the current publication. "But this is only half the truth: we were able to show that the high electrical charge of the particles plays a decisive role. It is the reason that the particles on the surface can do much more damage than previously thought."

When the particles of the solar wind are multiply charged, i.e. when they lack several electrons, they carry a large amount of energy which is released in a flash on impact. "If this is not taken into account, the effects of the solar wind on various rocks are misjudged," says Paul Szabo. Therefore, it is not possible to draw exact conclusions about the surface rocks with an incorrect model from the composition of the exosphere.

Protons make up by far the largest part of the solar wind, and so it was previously thought that they had the strongest influence on the rock. But as it turns out, helium actually plays the main role because, unlike protons, it can be charged twice as positively. And the contribution of heavier ions with an even greater electrical charge must not be neglected either.

A cooperation of different research groups was necessary for these findings: High-precision measurements were carried out with a specifically developed microbalance at the Institute of Applied Physics. At the Vienna Scientific Cluster VSC-3 complex computer simulations with codes developed for nuclear fusion research were carried out in order to be able to interpret the results correctly. The Analytical Instrumentation Center and the Institute for Chemical Technologies and Analytics of the TU Vienna also made important contributions.

The Daily Galaxy via Institute of Applied Physics at TU Wien

Most Viewed Space & Science Headlines

Homo Naledi, Newly Discovered Species --"Maybe We've Had the Story of Human Evolution Wrong the Whole Time"

Stephen Hawking's Great Question --"Why Isn't the Milky Way Crawling With Mechanical or Biological Life?"

"Alien Minds" --'Artificial Intelligence Is Already Out There, and It's Billions of Years Old' (VIDEO)

"Point of No Return" --MIT Scientist Predicts the Event Horizon for Earth's 6th Mass Extinction 

A Neutron Star Collision in Our Milky Way Neighborhood Could Destroy Earth

 "300-Million Nuclear Bombs" --New Insights Into Global Impact of Titanic Chicxulub Mass-Extinction Event

Stephen Hawking: Wake Up, Science Deniers! --"Earth is Morphing into Venus" (WATCH Today's 'Galaxy' Stream)

"Evolutionary Leap?" AI is Mimicing the Human Brain --"But Several Orders of Magnitude Faster and More Efficiently

China Creates a Laser of Mind-Boggling Power --"Could Rip Space Asunder, Breaking the Vacuum"

"Stop Saying That Dinosaurs Went Extinct. They Didn't"

6a00d8341bf7f753ef01bb09f898b6970d-800wi

Comments

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Your Information

(Name is required. Email address will not be displayed with the comment.)