(ABC News) An asteroid 100 feet in diameter is expected to whiz by the Earth later today (Wednesday) at only 216-thousand miles away. That's a close call as far as astronomers are concerned although it poses no threat to Earth. To put its distance in perspective, the big rock will pass 20-thousand miles closer than the moon. It will be nearest to Earth at around 4:07 pm [ET] but it's not expected to be visible to the naked eye. Star-gazers can track it virtually though right here.