Alien Planet May Be in Habitable Zone After All

The orbits of planets in the Gliese 581 system are compared to those of our own solar system. The Gliese 581 star has about 30 percent the mass of our sun, and the outermost planet is closer to its star than we are to the sun. Gliese 581d might be able to sustain liquid water on its surface.
The orbits of planets in the Gliese 581 system are compared to those of our own solar system. The Gliese 581 star has about 30 percent the mass of our sun, and the outermost planet is closer to its star than we are to the sun. Gliese 581d might be able to sustain liquid water on its surface. (Image credit: Zina Deretsky, National Science Foundation)

The alien planet

Gliese 581d, another

"The fact that

Article continues below

The Gliese 581

Gliese 581 is a red

Gliese

But some researchers

The two planets on

Gliese 581d, on the

Modeling an alien

Gliese 581d is

Von Paris and his

The research team

The team's model

In the end, the

A medium- or

"I found it

Von Paris and his

Lots of caveats

Another

Such work, while

"The problem,

Astronomers aren't

While von Paris is

"Gliese 581 is

  • Gallery:

You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall.

Mike Wall
Spaceflight and Tech Editor

Michael Wall is the Spaceflight and Tech Editor for Space.com and joined the team in 2010. He primarily covers human and robotic spaceflight, military space, and exoplanets, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.