Meteoroids Change Atmospheres of Earth, Mars, Venus

[Hum]

Meteoroids streaking through the atmospheres of planets such as Earth, Mars and Venus can change these worlds' air, in ways that researchers are just now beginning to understand.

Most planetary atmospheres are made up of simple, low-mass elements and compounds such as carbon dioxide, oxygen and nitrogen. But when a debris particle, or meteoroid, passes through, it can shed heavier, more exotic elements such as magnesium, silicon and iron.

Such elements can have a significant impact on the circulation and dynamics of winds in the atmosphere, researchers say.

"That opens up a whole new network of chemical pathways not usually there," said Paul Withers of Boston University.

Part of a planet's upper atmosphere, the ionosphere contains plasma ? a mixture of positively charged (ionized) atoms or molecules and the negatively charged electrons stripped from them. When simple elements such as oxygen move into this outer shell, they break apart easily, decaying in a matter of minutes.

But meteoroids streaking toward a planet's surface carry heavier metals that can be removed in a variety of ways. A grain of dust, for instance, may rapidly burn up, shedding already-ionized magnesium as it falls. Or, neutral magnesium may be torn from the small rock, then receive a charge from sunlight or from stripping an electron from another particle. The newly charged elements can take as much as a full day to decay.

Meteoroids that blaze a trail through the atmosphere are called meteors, or shooting stars. Only those that make it to the ground are meteorites.

"When we add metal ions to the ionosphere as a result of this meteoroid input, we create plasma in regions where there wasn't any plasma there to start out with," Withers told SPACE.com.

"If you stand at the surface of the two planets, they are very different," Withers said. "But up at about 100 kilometers (62 miles), conditions are surprisingly similar."

The pressures, temperatures, and chemistry at high altitudes are comparable for the two planets. So too are many of the properties of the layers of charged particles shed by meteoroids.

"The plasma densities are quite similar on average on all three planets, which is not what you might expect on the first impression," Withers said, referring to Earth, Mars and Venus.

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[zeta_immersion]

while I do agree, what is the extent of this ... also in the case of the earth ... all the junk from US/USSR-Russia/Europe/China-Japan that falls to earth impacts the atmosphere much more than the rocks ... then again, I have no clue as to the composition of rate of such events

Would be interesting if governments would dump 100bil on science and exploration annually ... hello f-ing science

[cacoe]

while I do agree, what is the extent of this ... also in the case of the earth ... all the junk from US/USSR-Russia/Europe/China-Japan that falls to earth impacts the atmosphere much more than the rocks ... then again, I have no clue as to the composition of rate of such events

Would be interesting if governments would dump 100bil on science and exploration annually ... hello f-ing science

In any given day, the estimates are than the Earth intercepts about 19,000 meteorites weighing over 3.5 ounces, every year of which fewer than 10 are ever recovered. About 2800 meteorites are in museums from previous 'falls' and are chemically found to represent about 20 or so distinct parent-bodies. The Earth acquires about 100 tons per day of dust-sized micro- meteoroids.

[Growled Member]

The Earth acquires about 100 tons per day of dust-sized micro- meteoroids.

That's a lot of little rocks.

[Hum]

^ What is not realized as yet, many of those little rocks are formed within the Earth's own vortex. ;)