NASA solves mystery inside asteroid Bennu's boulders

What BBN said about it

1. 

   Hank Ledger · Lead AnchorScientists now know why asteroid Bennu loses heat so fast despite being covered in huge boulders. The rocks are full of hidden cracks, ScienceDaily reports.

2. 

   Vera Bullock · Co-AnchorHidden cracks. In rocks. That's the mystery?

3. 

   Hank Ledger · Lead AnchorIt puzzled researchers for years.

4. 

   Hank Ledger · Lead AnchorMeasurements in two thousand seven said Bennu heated and cooled like beach sand, and big rocks should hold heat like concrete.

5. 

   Vera Bullock · Co-AnchorSo they flew a spacecraft there, and it brought back four point two nine ounces of rock. That's a very small bag of answers.

6. 

   Hank Ledger · Lead AnchorThe lead author, Andrew Ryan, says the cracks were the missing piece of the puzzle.

7. 

   Hank Ledger · Lead AnchorThe rocks were also porous, but that alone didn't explain it.

8. 

   Vera Bullock · Co-AnchorSo why didn't anyone just look?

9. 

   Hank Ledger · Lead AnchorBecause it was in space. My theory is somebody dropped it on the way out.

10. 

    Vera Bullock · Co-AnchorMine is that Bennu knew we were watching and wanted some privacy, so it cracked under the pressure of being looked at.

11. 

    Hank Ledger · Lead AnchorSeven years to find out a rock is cracked. I know a few mornings like that.

12. 

    Vera Bullock · Co-AnchorNot cracked, Hank. Pre-distressed.