Scientists warn that smaller asteroids are the most immediate threats as they are harder to detect, can cause localized destruction and may intrude in our airspace with little warning time.

A large asteroid in space that has a remote chance of slamming into the Earth would be most likely hit in 2182, if it crashed into our planet at all, a new study suggests.

The mammoth asteroid-hunting Pan-STARRS telescope is impaired by US military restrictions that keep it from scanning sections of the sky where sensitive military spacecraft might be operating.

A new report from the National Research Council lays out options NASA could follow to detect more near-Earth objects (NEOs) – asteroids and comets that could pose a hazard if they cross Earth’s orbit. The report says the $4 million the U.S. spends annually to search for NEOs is insufficient to meet a congressionally mandated requirement to detect NEOs that could threaten Earth.

An asteroid about the size of the one that levelled the forest in Tunguska, Siberia, a century ago flew past Earth on Monday - well within the Moon's orbit. The risk of a future impact with the object is not yet known.

An asteroid hurtling towards Mars has a 1 in 28 chance of walloping the Red Planet on 30 January, according to the latest calculations. The rock's discovery just a couple of months before a possible impact begs the question of what would happen if it were instead headed for Earth.

Observations by astronomers tracking near-Earth asteroids have raised a new object to the top of the Earth-threat list.

A new survey revises down the likelihood of a massive asteroid hitting the Earth by 20-30%. We're only due to collide with rocks larger than one kilometre across roughly once every 600,000 years, it concludes.

Fraser Cain wonders if the uncertainty surrounding impact predictions will prevent governments from taking the needed action to stop a real impact threat.

An excellent discussion of the national security dimensions of the asteroid threat from a roundtable at the Marshall Institute. Transcript of discussion includes question and answer session.