The entire universe in blog form

March 5 2014 11:00 AM

“Tiny” Asteroid to Give Us a Close Shave Today

By Phil Plait
 

At about 21:00 UTC (4:00 p.m. Eastern time) today, the 25-30 meter-wide asteroid 2014 DX110 will pass just 350,000 km from the Earth—closer than the Moon!

We’re in no danger from this rock on this go-round, which is nice; it’s somewhat bigger than the one that exploded over Russia in 2013 so I prefer it keeps its distance. But you can watch the pass live using the Virtual Telescope Project, an observatory that will follow the asteroid and send images out on the web. The picture at the top of this post was taken yesterday, Mar. 4, 2014, when DX110 was still about 1.5 million km (900,000 miles) from Earth. It’s far too faint to see with the unaided eye even during this close encounter, so your best chance is to see it online.

An orbital diagram for the asteroid shows it passing so close the labels for it and Earth overlap. Space is big - that's why it's called "space" - so in fact it will miss us by a decent margin.

diagram by NASA / JPL

You should know that rocks this size pass close to the Earth fairly often, but rarely hit us—a circle 350,000 km in radius has 3,000 times the area of the Earth! So we’re a pretty small target as things go. Averaged over time, a 25 meter asteroid is expected to hit us very roughly every 50 years or so, and would generally do so over the ocean and uninhabited territory. But rocks this size do hit us and eventually one will if we don’t do anything about it. That’s why it’s something we should be aware of and working on.