Chances are, that UFO everyone saw yesterday at around 10pm wasn't asteroid 2012 BX34.

David Clarke, an astronomy prof at St. Mary's University says, unless your eyes are eight inches wide, you'd never see it.

"The brightest it will get is 14th magnitude---about the brightness of Pluto. One would need to know exactly where to look and have at least an 8-inch telescope to see it," said Clarke.

"If more than a hundred people worldwide are aware of its passing as it happens, I'll be surprised," Clarke adds.

According to Universe Today, the 11-metre-wide (BBC says that's about as big as a double-decker bus) asteroid is passing within 60,000km (inside the orbit of the moon) of the earth in its wobbly orbit around the sun.

You can't really tell the rock bus from the Earth on this orbit calculator thingy from Nasa's JPL Small-Body Database Browser
That's how close the two heavenly bodies seem.

But it's no threat to the Earth, says Clarke:

Were it to enter the atmosphere, it is too small to impact the surface intact. The atmosphere would break it up into much smaller bits that would give a hell of a light show to those in the immediate vicinity, but would pose no threat to the earth in general. If a large enough bit were to strike a building, the building could be severely damaged, but the odds against such a hit would be, well, astronomical."

It's kind of funny that this morning in our daily mailout (yeah, we use email to get this thing out, too—write me if you want in), I said "What the heck was that thing everyone saw in the sky last night? Was it the express bus from Mars?"

Nope. Now, we have no idea what the heck people saw. I guess we need another expert to fill us in on this. Anyone?