Tallahassee Invaded by Martian Meteorites
The planet Mars is closer than you think. A Tallahassee researcher has a rare collection of rocks from the Red Planet and will be showing them off and talking about them the evening of Tuesday, October 1st.
The scientist’s name is Munir Humayun. And when you meet him, don’t be surprised if he’s quick to pull an object from his pocket and place it in your hand.
"That is an expoxy puck that contains a small piece of the meteorite inside it and it is that piece of meteorite that we have done our studies on and identified it as this ancient cratered terrain from Mars."
The sliver of rock inside the clear epoxy is a rather unremarkable dark gray color with a few even darker speckles on its surface. So the obvious question seems to be, how would we know this came from Mars?
"There have always been a class of meteorites that puzzled us because when you do radiometric ages of meteorites it's very easy to see that they're all 4.5 billion years old and there's no rock on earth that's ever given us a 4.5 billion year old age."
This particular piece of meteorite, Humayun says, fits neatly into that incredibly old age bracket. Also its mineral makeup matches the soil samples collected and analyzed by the robot spacecraft, such as the rover “Curiosity”, that have been checking out the planet‘s chemical composition. How do little chunks of Mars wind up on earth?
"Well it has to start with an impact on Mars and since Mars is close to the Asteroid Belt you can imagine there are plenty of impacts that occur. Mars has a small gravitational field and so when you hit it with a really big impact, bits of rock go flying out. Mars has very little atmosphere to stop those things from flying out into space and then they spiral in towards the sun and eventually some of them hit the earth."
Today, Mars seems to be a cold, dry lifeless world incapable of supporting life as we know it. However there is considerable water on the planet, now locked away within the soil itself. And, in the case of Humayun’s meteorite, there are tiny pockets of ancient Martian atmosphere. In essence, he says, a time capsule of Mars as it was millions of years ago.
"We now have the first of these samples that have just been recognized. It's very exciting because it opens up a whole new view of ancient Mars. And if there was ever a chance for life, this is where 'little green bacteria' would have first taken root."
All the marvelous research aside, there’s something indescribably wonderful about actually cradling a chunk of another planet in your hand.
"You're holding something that would cost hundreds of billions of dollars to recover if we had to go and grab one ourselves."
But this little piece of Mars came with a much cheaper price tag when it simply fell to earth in the Sahara Desert awhile ago and eventually wound up in Munir Humayun’s collection. Tuesday evening, he’ll bring part of that collection to Tallahassee’s Backwoods Bistro on East Tennessee Street for another in the National High Magnetic Field Lab’s series of Science Cafes. The free program starts at a quarter past six and, if you go, you might want to arrive early. After all, it’s not everyday you get a chance to hold another world in your hand.