What do we hope to learn?

Well for starters scientists have never had the opportunity to view an asteroid impact as it is happening.  They were able to watch the Shoemaker-Levy comet strike Jupiter, but that is a different type of observation entirely.

Here we are talking about a planet strike.  There it was an impact into the atmosphere.  For the potential Mars impact we have two ground based rovers and an orbiting satellite.  For the Jupiter impact...none of that.

This is historic.

According to the latest data the likelihood of an actual strike keeps going up.  From 1-in-75 down to now a 1-in-25 chance, or approximately a 4% chance.

LA-Times Story