A known asteroid will sweep within 217,000 miles (about 350,000 kilometers) of Earth today (Wednesday, March 5, 2014). That is closer than the distance from Earth to the moon. The time will be about 2100 UTC (1 p.m. PST, 4 p.m. EST). You can watch online via the Virtual Telescope Project or via Slooh.com.
NASA says that – with current detection capabilities – it can see an asteroid passing this close about 20 times a year.
This asteroid, 2014 DX110, is estimated to be about 100 feet (30 meters) across. It is no threat to Earth.
Astronomers discovered 2014 DX110 on February 28, 2014 via the Pan-STARRS 1 survey. Its orbit was initially refined using follow up observations made by the Great Shefford Observatory in West Berkshire, England.
NASA detects, tracks and characterizes asteroids and comets using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called “Spaceguard,” discovers these objects, characterizes a subset of them and identifies their close approaches to determine if any could be potentially hazardous to our planet.