Recovering a meteorite
On the 4th of January this year, an Italian dog walker found a chunk of rock that had fallen from the sky three days earlier. How did he do this? He was looking for it after having been told it had landed in the area.
|January 1st, 18h 26min UT fireball trajectory calculated from the 8 PRISMA/FRIPON video detections. Credit: PRISMA/FRIPON|
This is the first meteorite that’s been found - in Italy at least - after a targeted search. Up until now, all meteorites have been found purely by accident.
Across Italy and surrounding countries, there is an extensive (and growing) network of all-sky cameras, a bit like the ASV’s camera at their dark sky site (asv.org.au/lmro_skycam). These cameras are co-ordinated by the Italian National Institute of Astrophysics, and are placed to detect meteors. Together, the system is known as PRISMA (Prima Rete Italiana per la Sorveglianza sistematica di Meteore e dell’Atmosfera).
When a meteor enters the atmosphere, it gets heated by the surrounding air and burns. The brightest meteors, known as bolides or fireballs, show up on the PRISMA cameras. If the system records the same fireball on several cameras, a computer can calculate the trajectory of the meteor as it falls.
In this case, eight cameras got to see the fireball for up to six seconds. They picked it up at an altitude of 32km, and lost it at about 20km. This was plenty of information to calculate the trajectory. It’s shown in the image, and was used to identify an oval-shaped search area 2.2 x 1.5km in size, including the village of Disvestro.
It looks pretty scary to me. Imagine an 8kg asteroid heading down towards you like that. It re-entered at around 12 km per second!
Once the search area was identified, the public was informed and it wasn’t long before the dog-walker found two lumps, which totalled a healthy 55 grams. Researchers are hoping that more will be found.
Talk about a needle in a haystack!
More information: www.imo.net/new-year-italian-meteorite-recovered