Sunday, March 31, 2013


Last year in Morocco there was an amazing find; a green rock. But not just any rock. This rock has the distinction of coming from Mercury. It has been decided (by meteorite scientist Anthony Irving) that it is either of Mercury itself or a body smaller than Mercury but very much like her.

The most common location meteorites hail from is Mars or Vesta. (Vesta is one of the largest Asteroids in our system.) These meteorites have very specific chemical make ups that cause them to be easy to distinguish. The green rock of recent discovery has a very different composition, unlike any other previously discovered.

Believing that this green rock resulted from a planet or asteroid with flowing magma on its surface, Meteorite Scientist Anthony Irving thinks that perhaps the rock formed as “scum” on the cooling magma. The data sent back from NASA’s Messenger, a robotic NASA spacecraft now circling Mercury, has been found to give parallels from the planet’s low magnetism to that of the green meteor. Additionally the iron content the data represents as present on Mercury’s surface is also found in the green rock.

Looking beyond the Green Rock of Mercury one has to wonder where in general Meteors come from – are there meteors from Earth on Mars?

In January, NASA reported that a meteorite found in 2011 and nicknamed Black Beauty was determined to have originated on Mars. While coming from a planet seems an odd distinction consider that over 61,000 meteorites have been known to plummet to earth and of those 114 have been identified as Martian due to their elemental and isotopic compositions.

So how would it be possible for there to be earth meteorites elsewhere?

While we can only speculate on the process, we have determined that an action called accretion exists where dust granules collide and become stuck together forming a pebble, then a boulder, and eventually planets. This process can result in a planet and some left over material that then becomes a meteoroid but with the same composition that the planet would have. Of course some may be parts of asteroids or moons or planets, cast off when a large asteroid or meteoroid collided with them. Thus it follows that if earth had numerous collisions over its long history amounting to one every 20,000 years or so, there may very well be meteorites on Mars from Earth.

To further clarify, there are many terms – asteroid, meteors and meteorites or micro-meteorites and finally meteoroids, which might seem confusing. Their definitions starting with asteroid are; an asteroid is a rocky object in space that is smaller than a planet. Often they are called planetoid or minor planets. A meteor is an asteroid or similar object that vaporizes upon entry into the earth’s atmosphere. Another common ‘name’ would be shooting star referring of course to the dramatic plunge into our atmosphere, burning up in the process. And what if it survives entry through the atmosphere and lands on our planet? Then it earns the name meteorite. (A micro-meteorite is just a meteorite of 2mm or less) Finally meteoroids are pieces of either a comet or asteroid that remains in orbit around the sun.

OF INTEREST: NASA has proposed an Asteroid-Capture mission in its 2014 budget. There are several reasons for wanting this mission. Besides having an Obama deadline for a manned mission to an asteroid looming overhead, there are so many positives for NASA. From the spoils of the journey – the resources obtained, to the know-how that is gained in the experience and discovery of a substance from asteroid rock to a specific element that an provide a shield to radiation in space. And as is always the case when NASA goes new places, here on earth there are new inventions and discoveries in unrelated areas that benefit all mankind!

No comments:

Post a Comment