Peruvian Meteorite May Rewrite Impact Theories
Written by Nicholos Wethington
On September 15th of last year, a meteorite impacted the Earth near the town of Carancas in Peru. The story made worldwide headlines when hundreds of people who flocked to see the crater reported getting ill. As it turned out, there were no mysterious space illnesses plaguing the population; the super-hot meteorite likely vaporized arsenic-containing water that was near the surface of the impact site, and onlookers and investigators breathed in the noxious gas. The meteorite is again in the spotlight, though not for making people sick.
Researchers estimate from their analysis of the crater that the meteorite was of a rocky composition, and that it impacted the ground at a whopping 15,000 miles (24,150 kilometers) per hour. That is really fast for a stony meteorite! It is calculated to have been between .2 and 2 meters at the point of impact, and upwards of 3 meters when it entered the atmosphere.
“Normally with a small object like this, the atmosphere slows it down, and it becomes the equivalent of a bowling ball dropping into the ground. It would make a hole in the ground, like a pit, but not a crater. But this meteorite kept on going at a speed about 40 to 50 times faster than it should have been going.” said Peter Schultz, professor of geological sciences at Brown University, who presented the findings of his travels to the impact site at the 39th annual Lunar and Planetary Science Conference in Texas last week. Schultz collaborated on his research with a team of scientist from Brown University, Peru and Uruguay.
Stony meteorites – called chondrites – generally break up in the atmosphere and impact the ground at rather slow speeds. In fact, most of the objects that enter Earth's atmosphere end up never hitting the ground because the gases are so thick that the heat caused by air compression vaporizes them.
Schultz and his team think the Carancas meteorite may have initially broken up and then reformed in such a way as to make it more aerodynamic, allowing it to bullet through the atmosphere instead of being braked by the friction with the gases in our atmosphere. As opposed to dissipating and burning up like other chondrites, the meteorite landed as one large chunk.
This contradicts the conventional theory that small, rocky asteroids either can't impact at all, or create only small impact pits. If the new theory is correct, we may have to rethink the history and influence of meteorite impacts on the Earth, as well as consider what kind of damage they are capable of doing in the future.
Source: Brown University News Release
Filed under: Meteorites
March 18th, 2008 at 1:14 pm
so, the asteroid hits the atmosphere, starts to melt and during the melting process changes into an arrow shape.
klendatu, anyone???
March 18th, 2008 at 2:24 pm
it doesn't melt through, the interior of the meteorite is probably only a few degrees Kelvin on impact. I missed LPSC this year I would have liked to see this talk, the theory sounds fishy
March 18th, 2008 at 2:26 pm
Unfortunately, the IQ of this site runs down. The bullet is stabilized by fast rotation around its axis. If the meteorite did the same, it would be great puzzle.
March 18th, 2008 at 6:36 pm
ok, first the bullet thing is a theory. second (i think the first comment is about a story or something)but it is very possible that a rocky formation was able to reform into into a natural way of "rifling" due to the layout and chemicals involved. it would be nice to see the follow up.
March 18th, 2008 at 6:58 pm
If certain meterorites can make a bigger impact than expected then this is cause for concern and for more detailled study until the reason is determined. The conclusions could highlight the importance of the recent effort to find smaller near earth objects.
March 18th, 2008 at 9:52 pm
The first comment was referring to the movie / story of Starship Troopers.
March 18th, 2008 at 11:59 pm
"that the friction vaporizes them" should be:
"that the ram pressure vaporizes them"
March 19th, 2008 at 12:13 am
This was originally reported as a 'suspected' or 'possible' US satellite deorbiting, and that the locals were experiencing a reaction to hydrazine, a highly toxic and volatile rocket fuel.
That would explain both the intactness, and the 'sleekness', no? (50x faster than 'expected' is just plain BS).
March 19th, 2008 at 4:47 am
hopefully the book on meotorite theory is still open despite the possibility of space industry debris creating impact craters. you never really know what will come flying into our atmosphere, or even what dynamics are involved. new theories can lead to new truths.
March 19th, 2008 at 6:44 am
The notion that a US satellite cause that crater isn't impossible, but I'd call it highly unlikely. If a rocky meteorite didn't melt completely how would metal not melt? It's the reason that NASA puts ceramic based tiles on the bottom of the space shuttles - to decrease the effect of friction-caused heat on the fuselage during re-entry. The satellite would have broken apart during re-entry into the atmosphere (like Columbia) and it's probably not crazy to think that the satellite's fuel containment system would have probably exploded once the heat had worn down the exposed surface. Stop the conspiracy theories, people and just for a moment, use common sense.
March 19th, 2008 at 6:56 am
Ahhhh, some sense prevails… Thanks Eric
March 19th, 2008 at 7:46 am
It seems to me there is a lot more we don't know about our Universe than we do. Rather than immediately dismiss things that don't fit our expectations, let's ponder them for a few minutes.
Then dismiss them.
kcuhC
March 19th, 2008 at 9:26 am
If it hasn't been done already, find an archeologist with digging experience, and dig it up.
March 19th, 2008 at 10:14 am
Stoney meteorites are not always chondrites. Stoney meteorites can be either chondrites or achondrites.
March 20th, 2008 at 5:51 am
this may well be a nonstony meteorite but made of an unknown yet to be discovered matter which in contact with searing heat does not disentegrate but becomes plasticious its own velocity then causes it to elongate while retaining its whole mass and keep thining and lengthening and increeasing its velocity due to gravity in which case it is safe to assume the alien meteorite is still there with all its mass buried deep below the crater.
March 20th, 2008 at 6:44 am
That very well could be possible Giovanni. People need to just throw on some haz-mat suits and start digging. It's there gotta be in there somewhere - even trace amounts.
March 20th, 2008 at 8:29 pm
Chondritic material was found at the site. There is no doubt this was a meteorite impact.
Jon
March 24th, 2008 at 12:39 am
Is it already known from which direction the rock impacted Earth? Maybe that knowledge may give an explanation for the survival of the piece coming from heavens. If it hit the atmosphere right in front it had less atmosphere to pierce before impacting the ground.
March 24th, 2008 at 3:32 am
Yes we do. The object had came from an azimuth of 82 degrees relative to the crater (i.e. almost due east) and a descent angle of 63 degrees. The impact was an ordinary chondrite, class H4 or H5, travelling at 3-6 km/s. impacting at an angle of 45-60 degrees. Initial velocities were 12-18 km/s, mostly likely 16 km/s. The impactor’s orbit was probably inclined at 25 degrees to the ecliptic and an aphelion inside the orbit of Jupiter.
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1216.pdf
Jon
March 24th, 2008 at 3:34 am
The other LPSC abstracts about the event.
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2446.pdf
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2555.pdf
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2027.pdf
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2409.pdf
Jon
March 24th, 2008 at 7:52 am
Instead of pondering, why not experiment? Heat the remaining rock up with a torch and put a light source behind it and take a look with a spectroscope to see what it is made of. -Maybe it is space junk that made its way down.-Then put it in a wind tunnel and propel it through at a number of different speeds and record the results. We could always drop it from a balloon. Or, shape it into a bullet of the right calibre and fire it out of a cannon…?
What was the atmospheric conditions right where it entered? Did any jets leave some hot exhausts behind just moments before leaving some adhering gases in its wake?
March 25th, 2008 at 3:43 am
People have done that, it is an H4 or and H5 class chondrite.
March 26th, 2008 at 9:56 am
Thanks Jon.
March 26th, 2008 at 2:39 pm
You are welcome!
April 8th, 2008 at 6:00 pm
There's a difference between a rifle bullet which spins and a musket or smooth bore bullet which doesn't. The 2 are getting confused here. Second there seems to be some assumptions that rocks from space can't be big enough to hit the ground and are always round. It'd make more sense if the meteor was already elongated and found it's own path of least resistance. It would explain it hitting the ground in the first place and the speed in which it did. Hydrazine I believe is a caustic substance which would dissolve their lungs. As in not sick but dead.