Crisis: Asteroids & Comets

Russia's space chief said Wednesday his agency will consider sending a spacecraft to a large asteroid to knock it off its path and prevent a possible collision with Earth.

Although no one noticed at the time, the Earth was almost hit by an asteroid last Friday.

Using updated information, NASA scientists have recalculated the path of a large asteroid. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth in 2036.

Existing sky surveys miss many asteroids smaller than 1 kilometre across, leaving the door open to damaging impacts on Earth with little or no warning, a panel of scientists reports. Doing better will require devoting more powerful telescopes to asteroid hunting, but no one has committed the funds needed to do so, it says.

Late word out of the IAU's Minor Planet Center: a small asteroid will pass close to Earth tomorrow (March 2nd) at 13:44 Universal Time. How close? The MPC's Timothy Spahr calculates that it'll be 0.00047 astronomical unit from Earth's center. That's only about 40,000 miles (63,500 km) up -- well inside the Moon's orbit and roughly twice the altitude of most communications satellites!

According to a new theory about how mass dyings work, cosmic collisions generally aren't enough to cause a major extinction event. To be truly devastating, they must be accompanied by another event that inflicts long-term suffering, like runaway climate change due to massive volcanic eruptions.

Hazardous comets and asteroids are monitored by various space agencies under an umbrella effort known as Spaceguard. The vast majority of objects found so far are rocky asteroids. Yet UK-based astronomers Bill Napier at Cardiff University and David Asher at Armagh Observatory in Northern Ireland claim that many comets could be going undetected. "There is a case to be made that dark, dormant comets are a significant but largely unseen hazard," says Napier.

A meteorite impact off Long Island 2,300 years ago may have set off a huge tsunami that flooded the New York City region, a new study says (New York City and Long Island map).

A blue-ribbon panel of scientists is trying to determine the best way to detect and ward off any wandering space rocks that might be on a collision course with Earth. "We're looking for the killer asteroid," James Heasley, of the University of Hawaii's Institute for Astronomy, recently told the committee that the National Academy of Sciences created at Congress' request.

How close have we come to death from the skies? The October 2008 encounter over Sudan with a three-metre-wide asteroid provides the best confirmation in a while that objects larger than harmless little "shooting star" particles can score a direct hit on Earth. Though this particular asteroid burned-up in the atmosphere, larger such objects could make landfall. The really scary thing is that we really have no way to detect what might be hurtling toward us right now.