Greenland’s 836,000 square miles are mostly frozen—but only on top. It has the potential to be as cozy as a den with a fireplace

The (currently) Danish possession of Greenland can be a proving ground for the next stage of human civilization.

The core of the Earth is as hot as 7,000 degrees Fahrenheit —about the same temperature as the surface of the Sun .

Houston is on its way to becoming the world’s geothermal hub.

It may take a while for even our solar system to be safe for human spacefarers, says John F. Kennedy /Elon Musk vision of spacefaring.

Space is guided by the misanthropic principle: the briefest unprotected exposure will instantly kill a person.

Astronauts who spend three months in space are bombarded by 10 times the millisieverts judged to spur cancer.

The longer they’re in space, the worse off, the longer they are in space.

Frida Ghitis: The Moon has 16 percent of Earth ’s gravity, and Mars has 38 percent as much as much.

Ghitis asks: Is that enough to keep humans healthy? She says it's doubtful, but there's only one way to find out—spending long periods of time on each planet.

She says C.S. Lewis foresaw this in his work of 1943 , The Abolition of Man: Our power over human biology is really our power over individuals, as well as over humanity as a whole.