Fireball over Russia

I was planning on blogging about alien design today, but, really, how can I resist blogging about a major meteorite event and a close fly-by of an asteroid happening on the same day

Earlier today a fireball came apart over Russia and there are reported associated meteorites.

            http://rt.com/news/meteorite-crash-urals-chelyabinsk-283/

Someone on the American Meteor Society has already estimated a rough orbit:

            http://www.amsmeteors.org/2013/02/large-daytime-fireball-hits-russia/

I cannot wait to see what is learned from this event.  Very exciting!

And on the same day we have a close fly-by of an asteroid (closer to the Earth than the Moon or geosynchronous satellites).  But this one won’t hit us.

            http://www.space.com/19781-asteroid-2012-da14-flyby-webcasts.html

It is an exciting day for space news!

Rocks from Space!

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A number of years ago, during a visit to Texas Christian University, I visited the Oscar Monnig meteorite collection.

http://www.monnigmuseum.tcu.edu/Home.html

Before this visit, I knew what meteorites were (rocks from space that actually make it to the Earth’s surface), but I had never given much thought to where they came from (other than the famous Mars meteorite).

Scientists, of course, had thought about it and have figured out the “parent” source of some meteorites.

A few meteorites have been caught on camera as they heat up falling through the Earth’s atmosphere, and their previous orbits can be determined from that data.  The results show that most meteorites came from the asteroid belt.

An early example is here:

http://hyperion2.cc.uregina.ca/%7Eastro/Peek_1.pdf

Some clever scientists set up their cameras where it would be easy to find any meteorites that made it to the Earth.

http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_18-9-2009-11-20-41?newsid=73461

Radar data can also be used to find meteorites and figure out where they came from.

http://cams.seti.org/Science-Manuscript-SM.pdf

But meteorites that are caught on camera during reentry are rare.

Scientists can also measure the reflection spectra of meteorites (the amount of light reflected back at various frequencies) and compare them to the telescopic spectra of various asteroids.  They found some pretty close matches:

http://www.mtholyoke.edu/~tburbine/Burbine.asteroidsIII.20002.pdf

But not all meteorites come from asteroids.  Some come from planets.

Martian meteorites tend to be “young” and contain gases that match the Martian atmosphere measured by the Viking spacecraft.

http://curator.jsc.nasa.gov/antmet/mmc/Chap%20I.pdf

Lunar meteorites are also identified by their mineralogy and chemistry.

http://meteorites.wustl.edu/lunar/howdoweknow.htm

Recently, a meteorite was found in Africa that might originally be from Mercury:

http://www.skyandtelescope.com/news/home/The-First-Ever-Meteorite-from-Mercury-189374981.html

How cool is that?