APOD 2005 05 16

Serge Cote · Post by **Serge Cote** » Thu Jun 16, 2005 9:25 pm

"The remaining crater may tell how Tempel 1 is constructed. If, for example, Comet Tempel 1 is an extremely loose pile of debris, the impactor may leave little or no discernable crater. On the other hand, if the comet's surface is relatively firm, the impactor's ripple may leave quite a large crater."

A copy from APOD text of 2005 05 16.

Is this prediction is inversed? The harder the commet is, the smaller the crater wiil be. Tell me if I am right or wrong.

Regards

makc · Post by **makc** » Fri Jun 17, 2005 10:47 am

imagine liquid comet. there would be no crater at all.
I guess it is about how much of impact energy can be consumed for plastic deformation - if none, it would have to crack, leaving large crater.

Orca · Post by **Orca** » Mon Jun 20, 2005 2:46 pm

makc wrote:imagine liquid comet. there would be no crater at all.
I guess it is about how much of impact energy can be consumed for plastic deformation - if none, it would have to crack, leaving large crater.

That sounds about right to me.

How about a brick dropped into a box of polystyrene packing peanuts? The surface layer of peanuts looks pretty much the same before and after the impact, because the peanuts are so loose that they just get jumbled around and rearrange themselves.

If you dropped the same brick on a glass table, it would make a nice hole (or at least some cracks due to the impact) because the glass can't move around freely when it gets impacted and the energy has got to go somewhere.