How to watch a house-sized asteroid buzz by Earth – CNET

asteroid2012tc4

Near Earth Asteroid 2012 TC4 is surrounded by a blue circle in this ESO image.

ESO/ESA NEOCC/O. Hainaut (ESO), M. Micheli (ESA) & D. Koschny (ESA)

A cosmic close call is set to occur high above Earth late Wednesday night (Pacific time) when an asteroid the size of a house passes almost as close to us as some of the communications satellites that make it possible to read this story around the world. 

Asteroid 2012 TC4 is back for another visit almost four years to the day since it was seen for the first time zipping by our planet. This time there’s a few ways you can watch the space rock’s fly-by as it happens.

A week after being discovered in October 2012, TC4 passed us at a distance of 58,900 miles (94,800 kilometers). This time it will come closest at approximately 10:41 p.m. PT Wednesday (5:41 UTC Thursday morning) when it slices by safely at a distance of about 31,000 miles (50,000 kilometers). For reference, satellites in geosynchronous orbit are at an altitude of about 22,236 miles (35,786 km). The asteroid will actually pass closer than some satellites in more elliptical orbits, like NASA’s Interstellar Boundary Explorer.

Observatories around the world have been working to track the asteroid over the past several weeks, using it as an exercise to test the early warning network that would be used should another future space rock pose a real threat of impact.