Mystery object to whizz by earth on Wednesday

 
Scientist don't know what it is, an asteroid, space junk?  Something is going to pass within 80,000 miles of earth and they don't know what it is?  Seems strange.  It's 33-50 feet wide and it's 80,000 miles out (at it's closest), doesn't seem like a good candidate to be space junk.... at least not space junk from Earth (alien space junk maybe?).  If we assume it's an asteroid that would explain it's mysterious origin but it's a bit disturbing that something that big remained unknown until now and it still can't be identified.  At least they're saying that if it is an asteroid it's tiny, too small to cause much damage even if it does hit.  I assume most of it would burn up in the atmosphere before it reached the earth.  Hmm, maybe it's a Borg scout ship, or maybe a miniature Deathstar?