Well,Setting a specific timeframe helps increase chances of the goal being met by Having a Specific time for that goal to be met,which leads to doing whatever the goal is by devoting time to that goal
The crater is not large enough to cause any permanent damage such as flooding, extinction for weather patterns. Since it is falling from the sky at such a great velocity it will of course leave a little "dent" in earths surface. This is short term because overtime the crater will fill in an become flat ground.
