Scientists of the European Southern Observatory (ESO, headquartered right here in Munich!) discovered a planet orbiting Proxima Centauri, the nearest star to us.

If the solar system were a condo, this planet---called Proxima Centauri b or Proxima b for short---would be an apartment in the building across the street! Whether anyone lives there, however, is a completely different story.

Unable to see the planet directly, the team of scientists used an ingenious system to find it, carefully analyzing the light from Proxima Centauri.

From our point of view, the star slowly moves back and forth, periodically, and as it does, its light shifts in color, like the sound of a siren shifts in pitch as it passes by. From this so-called "doppler shift", the scientists figured that the star's wobbling was due to Proxima b tugging on it with its gravity while orbiting.

They also teased out a few details about the planet: it's some 1.2 to 3 times the mass of Earth, probably has a rocky surface, and could have a permanent day on one side and a permanent night on the other.

Despite being very close to its star (just 7 million kilometers, much nearer than Mercury is to the Sun), Proxima b is right in the "habitable zone", where it is reasonably possible to have liquid water.

Whether it actually does is completely unknown, and less even whether it has life. A lot depends on the planet's atmosphere, and on whether it has a magnetic field to protect it from the radiation blasting from Proxima Centauri.

Reaching Proxima b with our current probes would take millennia, so we'll have to get our answers turning telescopes, including (when it launches) NASA's mighty James Webb Space Telescope.

Image credit: M.Kornmesser/ESO