Cameron’s movie Avatar looks at telepresence and remote interaction. The biological telerobots portrayed are well beyond our present state of the art. However telepresence and telerobots made of metal, silicon and plastic aren't science fiction, they are being used today.

Avatar also portrays more plausible puppets made of metal, silicon and plastic ( Read more... )

In his blog  Stranded Resources Tom Murphy argues that space resources will likely remain beyond our reach. He concludes humanity should learn to live within its means and conserve our resources. This sound advice is the theme for most of his Do The Math blogs.

But the math on which he builds his argument is wrong.

To calculate delta V from earth to ( Read more... )