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Only a small handful of objects are known to pose a serious threat to Earth, and the gigantic asteroid Apophis is one of them. Scientists are now re-evaluating its potential to strike our planet in 48 years, owing to improved observations of the problematic asteroid. Observations made earlier this year from the Subaru Telescope in Hawai’i are providing astronomers with a better sense of how the Yarkovsky effect is influencing the orbital path of asteroid 99942 Apophis. This effect is like a built-in propulsion system for asteroids, in which trace amounts of leaking radiation can alter an object’s momentum in...

The English tabloid Express ran a story today (Feb. 11) with the headline "NASA warn 'APOCALYPSE asteroid' Bennu WILL appear in the sky this Valentine's Day." The piece claimed that the 1,640-foot-wide (500 meters) asteroid Bennu — "a doomsday asteroid which has a high probability of impacting Earth in one hundred years time" — will be "visible to the naked eye" on the night of Feb. 14, slightly to the right of Mars. This is entirely wrong. First of all, Bennu is not an "apocalypse asteroid," and NASA never labeled it such. (Agency scientists aren't known for their hyperbolic and...

Bennu has a shape that looks a bit like a spinning top. It is roughly 500 meters (1,640 feet) in diameter and orbits the sun once every 1.2 years, or 436.604 days. Every six years or so, it comes very close to Earth — about 0.002 AU, according to the University of Arizona. (... well within the orbit of Earth's moon.) Bennu is part of a small class of carbonaceous (dark) asteroids that likely have primitive materials in them. Called a B-type class, Bennu and other asteroids like it have materials such as volatiles (compounds with a low boiling point),...

Scientists on NASA's asteroid sample return mission, Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx), have measured the orbit of their destination asteroid, 1999 RQ36, with such accuracy they were able to directly measure the drift resulting from a subtle but important force called the Yarkovsky effect -- the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat... Observations that Michael Nolan at Arecibo Observatory in Puerto Rico made in September 2011, along with Arecibo and Goldstone radar observations made in 1999 and 2005, when 1999 RQ36 passed much closer to Earth, show that...