After some rough calculations, Cooke has been able to estimate the mass of the incoming object - around 70 metric tons. This was a fairly hefty piece of space rock. From this estimate he was also able to arrive at an approximate size of the meteor: "Hazarding a further guess at the density of 3 grams per cubic centimeter (solid rock), I calculate a size of about 3-4 meters, or about the size of a minivan."
Although there were numerous reports of sightings in Nevada and California, there was few immediate clues as to where the fireball ended its journey. But with the help of two infrasound stations, the source of the explosion could be resolved.
"Elizabeth Silber at Western University has searched for infrasound signals from the explosion," said Cooke. "Infrasound is very low frequency sound which can travel great distances. There were strong signals at 2 stations, enabling a triangulation of the energy source at 37.6N, 120.5W. This is marked by a yellow flag in the map (above)."
Interestingly, the estimated size of the California fireball is bigger than the small 3-meter-wide asteroid that exploded over Sudan in 2008. That one delivered an energy of 1.1–2.1 kilotons of TNT. Asteroid 2008 TC3 was actually the first-ever space rock to be detected before it hit the Earth's atmosphere. With astonishing accuracy, astronomers at Mount Lemmon telescope in Arizona managed to spot the tiny asteroid and infrasound stations in Kenya triangulated the location where the asteroid hit. Using this information, meteorite hunters were able to recover fragments of the impact.