We have not been created out of nothing, but from primeval "ur-matter," atoms formed billions of years ago that have for a brief while been gathered into collections that think they are us.

I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail for replacement in as many decades

Like most scientists, we felt that in the past human space exploration had been driven by politics and the science had been extremely thin.

The past may show the right way to behave if you live in the past, Stil, but circumstances change.

Autonomous robots alone will be unable to realize those scientific goals in the foreseeable future,

Human space flight beyond Mars is just not possible because of the increased exposure to galactic cosmic rays,