Neil spoke about it on Real Time last week as well.
All these worlds are yours except Europa.
Attempt no landing there.
Use them together. Use them in peace.
Why, I can smile, and murder while I smile,
And cry 'Content' to that which grieves my heart,
And wet my cheeks with artificial tears,
And frame my face to all occasions.
I can add colours to the chameleon,
Change shapes with Proteus for advantages,
And set the murderous Machiavel to school.
Can I do this, and cannot get a crown?