Moldavite



8 gram Moldavite specimen, approximately 5cmx1cm.

Moldavite is a glassy substance believed to have been formed approximately 15 million years ago, as a result of the Nördlinger Ries meteorite impact in Bavaria, Germany.

As the meteorite impacted the Earth, huge quantities of dirt/rock were instantly melted/ejected from the newly forming crater, hurled dozens to hundreds of miles downrange, or into low Earth orbit.

As the molten droplets cooled while re-entering the upper atmosphere, the drag forces produced regmaglypt like features, similar to those found on meteorites.

Since Moldavite originated on Earth, and was ejected by a meteorite impact, but later returned to Earth, it belongs to a class of objects known as "Tektites".

via Flickr http://flic.kr/p/nyhBsw

Advertisements

Mommy, what are planets made from?


I’ve wanted a piece of Tagish Lake ever since I first heard about the event.  It’s the first meteor fall that I heard about as it happened and immediately thought “I wish I could have a piece of it.”  Little did I know, Tagish Lake would turn out to be a very special meteorite, and that eventually, I really could have a piece of it.  It’s one of the few meteorites who’s original orbit could be accurately determined from it’s entry path, since it was observed by so many people, radars, etc.  NORAD kinda keeps an eye on shit streaking in from space over North America.

Before it hit the atmosphere, it weighed in at 50-100 tons.  It exploded in the upper atmosphere, with a force of about 1/10th of a Hiroshima, the standard unit of measure for ridiculously large explosions.   Luckily, some of the fragments that didn’t get obliterated rained down on a frozen lake.  They were recovered just as the weather was starting to warm up.  In a few weeks, the ice was melted.  If they’d been a little later, they’d have found nothing.  As is, only about 10kg was recovered on the ground in total, much of it in the form of little piles of powder and crumbles.  It has a texture very similar to charcoal.

A Fragment of the Tagish Lake Meteorite

A Fragment of the Tagish Lake Meteorite

It’s part of a class known as carbonaceous chondrites, meaning it’s got a fuckload of carbon in it, thus the pitch black coloring, and chondritic, meaning that it’s undifferentiated, i.e. came from a time before planets began to stratify, which means it predates the formation of the planets themselves.  Put another way, its part of what would have made a planet, if Jupiter hadn’t rolled into the neighborhood all drunk and rowdy.  These are some of the oldest things in our solar system.  They are older than the Earth itself.  It’s about 4.5 billion years old.  Our Sun is about 4.7 billion years old.

Early on, Earth was much too hot to hold onto any water.  Fortunately, there was an ample supply was held in reserve, out there in the asteroid belt, where it was a little cooler.  As Jupiter migrated inwards towards the Sun, it cleared out the competition on the way in, swallowing some, ejecting others from the solar system, but most importantly, sending a metric fuckton of them towards the Sun, and the lowly inner planets. In a gravitational battle between Jupiter and a small moon, Jupiter wins.  You didn’t see Dick Cheney blow up the princesses gas giant homeworld, did you?  No, because Jupiter woulda donkeypunched him straight to DVD.  This period is known as the Late Heavy Bombardment.  It would have been a pretty unpleasant time to be on Earth.  It’s when the maria, and all the big craters you see on the moon were formed, as piles, and piles of asteroids large and small(some of them very large), collided with the Earth and Moon.  Anyway, it’s a good thing, because without those, there wouldn’t be any water here, or much carbon.  You know, the stuff pretty much everything you know and love is made with.   Say “Thank you, Jupiter…”

Destabilized onto my shelf, yo.

Destabilized onto my shelf, yo.

Tagish Lake is more special than just that, though.  We know exactly(probably) where it came from, specifically, an asteroid named Irmintraud 773.  By measuring Irmintraud 773’s light with a spectrograph, and comparing its spectra to the spectra of Tagish Lake, measured here on Earth, we can see that the two are a very close match.  It’s a slightly closer match to a different asteroid, Hadea 368, but Irmintraud773 orbits pretty close to a Kirkwood Gap,where orbits get destabilized due to gravitational interactions with Jupiter.  This tends to kick stuff towards the inner part of the solar system, where they occasionally collide with Earth, because shit rolls downhill.

But wait!  It’s more special than that!(Oh god, I Jobsed.)  It’s chock full of things like diamonds, fullerenes, and all kinds of organics, including a few amino acids, the things proteins are built from.  According to recent news, it has 4 times more formic acid than any other known meteorite.   Take that, all other meteorites!  Formic acid is useful in facilitating chemical reactions between organic molecules.  That probably has something to do with why ants use it in their venom.

The diamonds inside are really tiny, micrometers or nanometers across, but Tagish Lake contains more of them than any other known meteorite.  It also contains fullerenes, cage-like molecules of carbon that can trap other atoms, or even small molecules inside.  The fullerenes and diamonds are the product of ancient supernovas in solar systems that predated our own, making them potentially much older than 4.5 billion years.  Inside those fullerenes are gasses trapped during their creation billions of years ago in the aftermath of a dying star, before our star was even born.

It looks exactly like charcoal.  In a sense, that’s exactly what it is.

From Mars to Earth in 1 easy step.


This is a piece of Mars, the planet.  It came to me via a meteorite, Dar Al Gani 476, some 60,000 years after it plopped itself down in the Libyan Sahara, to later be discovered on May 1, 1998.  This particular piece is about the size of your thumbnail, assuming you’re not some kinda freak with abnormally sized thumbnails.  It weighs in at a hefty .240 grams.

Dar Al Gani 476 a meteorite known to be from Mars

Dar Al Gani 476 a meteorite known to be from Mars

It was evicted from Mars with significant force some 1.1 million years ago, as a completely different, and much larger meteorite slammed into Mars with enough force to blast chunks of the planet clear into space, out of Mars’ orbit, and into orbit around the Sun, where they chilled out for a while, until a few of them eventually ran smack into Earth. DAG 476 was the 13th meteorite from Mars to be found, giving it the nickname “Lucky 13”.  It was the first to be found after ALH84001 was made famous in all that brouhaha about whether or not it contained traces of life, which unfortunately, it probably doesn’t.

DAG 476 is an achondrite, belonging to a class of meteorites known as the SNC group, which stands for Shergottites, Nakhlites, Chassignites, of which all members originate from Mars.  DAG 476 is of the Shergottite variety, which got its name from the Shergotty fall in 1865 in India.  It’s the most common sub-group of martian meteorites, having characteristics which suggest they solidified at, or near the surface of Mars out of magma from deep beneath the surface.  They don’t all come from the same place on Mars though, which means this has happened many times.  The composition of DAG 476 matches up perfectly with 4 other martian meteorites, DAG 489, DAG 670, DAG 735 and DAG 836, suggesting that all five were probably from the same body that broke up upon entry into our atmosphere.  There are about 30 different distinct meteorites known to be from Mars in total, if you count the multiples as one.  As a consequence of lying there on Earth for 60,000 years, the original fusion crust generated on entry into the atmosphere has long since eroded away, with veins of carbonate running through the occasional crack due to weathering.  I think those are the light greyish parts at the top, running down the left side, but I’m pulling that straight out of my ass, without any confidence whatsoever.

It’s kind of astonishing how much Science can tell us about this rock.  It crystallized originally to form a rock about 474 million years ago, which is actually quite young, by meteoritic standards, just a meter or two below the surface of Mars.  They can tell how deep it was buried by the rate at which it cooled, which affects the crystallization process.  There are shock features within, that point to it experiencing enormous shock, as it was blasted free of its homeworld, into space.  Incidentally, the age of 474 million years would also imply that there was volcanic activity on Mars less than half a billion years ago.  Geologically speaking, that’s pretty recent.  The alignment of the olivine, and pyroxene crystals within it indicate that it formed in an extruded lava flow.  I guess that means they’re stretched in one direction.  If Mars was geologically active 474 million years ago, there’s probably at least *some* activity today.  Perhaps not full fledged eruptions with lava flows, but it’s fairly likely that there is something.   When it was floating around in space, it was being bombarded by high energy cosmic rays, which are capable of smashing the atoms they collide with into smithereens, or being absorbed by them, turning into new, radioactive elements, like Helium-3, and Argon-38.  By measuring the relative quantities of these gasses, it can be determined how long it was in space.  When this rock landed on Earth, Man was just getting the knack of making stone tools.

The other side of Dar Al Gani 476, known to be from Mars

The other side of Dar Al Gani 476, known to be from Mars

How do we know it’s from Mars?  Well, back in the 1970s, one of the things the Viking landers did was sample the atmosphere on Mars, characterizing the relative abundances of gasses in the air.  It also sampled the soil, to determine the chemistry.  Inside this meteorite are wee little microscopic bubbles of trapped gasses that have been locked up in there ever since this rock formed, trapped inside of crystal cages.  Wouldn’t you know it, when sampled, those bubbles turn out to have the exact same proportion of gasses as the Martian atmosphere did, when measured by the Viking landers.  The composition of the rock itself is very similar to the composition of rocks on Mars.  In a neat scientific coincidence, one of the Mars meteorites, known as EETA79001, discovered in Antarctica in 1979, was found to be highly similar in composition to a rock nicknamed “Bounce” that was studied on Mars, by the Opportunity Rover.  The data seems to indicate that Bounce itself is from elsewhere on Mars.  It was also ejected in an impact, but not with enough energy to get launched into orbit around the Sun.  It’s conceivable that Bounce is even from the same event as EETA79001, it’s at least likely to be from the same place on Mars.  What are the odds of finding pieces ejected from the *same* meteorite impact on two different planets?  It boggles the mind.

This is my single most treasured possession.   What could possibly beat a piece of another planet?    I can point to it in the sky, and say “Yup, I’ve got a piece of that.”  It’s tens of millions of miles away, and it’s on my bookshelf.  It’s the only place in this solar system where we can seriously see ourselves living one day, in our craziest dreams and hilariously bad movies, perhaps not even in bubbles, or space suits.  It’s the only place remotely similar to Earth.  And it was generous enough to send a souvenier all the way here, to inspire us to dream big, so that one day, if we’re good little human beings, and we don’t kill ourselves first, we can go to Mars, and steal all that precious, precious land.  The best part?  There aren’t even any natives to oppress/subjugate/relocate/eliminate!  No guilt, and we get all the casinos to ourselves!