[Mitchell]

This object (2001 YB5) is big. Here are some comparisons, with approximate sizes for three actual impacts:

Tunguska, Siberia (1908)	50 m
Meteor Crater, Arizona (20,000 years ago)	100 m
2001 YB5 (now)	300 m
Chicxulub, Gulf of Mexico (65,000,000 years ago)	10,000 m

See 1908 Siberia Explosion: Reconstructing an Asteroid Impact from Eyewitness Accounts.

[blam]

The Arizona impact occurred 50,000 years ago.

[2nd_Amendment_Defender]

A meteor would most likely hit the Pacific Ocean and if it was big enough cause huge tsunamis and do great damage to Sydney, Australia, Japan, California and other places. Will you sleep soundly tonight now with that knowledge?