CAPE CANAVERAL (Florida) • A large asteroid that scientists discovered only this month will make a relatively close approach to Earth early tomorrow morning, astronomers say, providing one of the best opportunities in years to gather data about a passing space rock.
The asteroid, estimated to be about 400m in diameter, will shoot past the planet at 35km per second at around 1am Singapore time. Known as 2015 TB145, it will come within about 480,000km of Earth, farther away than the moon but relatively close by cosmic measures.
Astronomers hope to capture radar images and other measurements of the asteroid during the encounter, a rarity for scientists who typically rely on expensive robotic space probes to gather information about such rocky bodies. Scientists expect to learn about the asteroid's shape, dimensions, surface features and other characteristics.
"The close approach of 2015 TB145... coupled with its size, suggests it will be one of the best asteroids for radar imaging we'll see for several years," Dr Lance Benner, an astronomer at Nasa's Jet Propulsion Laboratory in Pasadena, California, said in an article posted on the US space agency's website.
Aside from pure scientific value, the encounter may help engineers develop better tracking techniques and countermeasures for asteroids that may be on a collision course with Earth. Small space rocks rain down on Earth constantly, with most disintegrating as they blaze through the atmosphere.
About 65 million years ago, an asteroid or comet roughly 10km in diameter crashed into what is now Mexico's Yucatan peninsula, triggering global climate changes that killed off the dinosaurs along with about 75 per cent of life that existed at the time, scientists say.
More recently, a 20m asteroid broke apart over Chelyabinsk, Russia, in February 2013, shattering windows and damaging buildings. More than 1,000 people were injured by flying debris.
Nasa is working to map potentially dangerous asteroids and comets that pass within 48 million km of Earth. Asteroid 2015 TB145 was discovered less than three weeks ago.
"That such a large object, capable of doing... damage if it were to strike our planet, was discovered only 21 days before closest approach demonstrates the necessity for keeping daily watch of the night sky," European Space Agency astronomer Detlef Koschny said.