NASA scientists have measured the size of a gigantic asteroid that could wipe out humanity while exploring a faraway galaxy, according to a news release from the National Radio Astronomy Observatory.
The asteroid, called Palma, was first spotted by French astronomer Auguste Charlois in 1893. It is in the main asteroid belt between Mars and Jupiter and orbits around the Sun along a steady trajectory, posing no threat to our planet.
Palma's true size remained unclear until a team of stargazers used the National Science Foundation's Very Long Baseline Array to study radio waves emanating from a remote galaxy called 0141+268. The asteroid blocked the radio waves from view while passing in front of it, helping the astronomers measure its size and even estimate its shape.
They discovered that Palma's diameter was 192 kilometers, dwarfing London (some 64km wide) and Berlin (45km). They also learned that Palma, like most other asteroids, differs significantly from a perfect circle, with one edge probably hollowed out.
"Observing an asteroid occultation using the VLBA turned out to be an extremely powerful method for asteroid sizing," said Kimmo Lehtinen of the Finnish Geospatial Research Institute. "In addition, such radio data would immediately reveal peculiar shapes or binary companions. That means that these techniques will undoubtedly be used for future asteroid studies."