The closest habitable extra-terrestial planet is in fact on one of our nearest stars
Just yesterday, researchers revealed that they discovered a rocky planet orbiting Proxima Centauri, the nearest star to our solar system at 4.5 light years away. In case you're unfamiliar with the term, a light year is the distance that a particle/wave of light travels in a year, which is 9.46 trillion kilometres. It's quite safe to say that we will not be visiting anytime soon.
Before you get your hopes up about escaping the planet before the world is consumed by runaway greenhouse gases and global warming melts the polar ice caps completely, here are a few things you should know about Proxima b.
1. We don't know if it has an atmosphere.
That's right. Assuming it doesn't, temperatures on the rocky surface would be a lovely -20 to -40 deg C. If it does have an atmosphere, the average temperature would be around 31-40 deg C. (Hello, Singapore weather all over again.) In addition that would also affect the planet's exposure to UV rays. It doesn't mean that the planet cannot host life, but it might be a bit different from us.
2. It's a lot closer to its star.
Proxima b has an orbit of 11.2 days which is great news for people who like to celebrate birthdays. That distance means it's incredibly close to its star, which is a dwarf star and therefore a lot cooler than the earth. That's why it's in the habitable zone of the star and also why it's taken so long to discover it. The planet's presence was pretty much hidden by the star and its surrounding brighter stars until the Very Large Telescope in Chile was directed to the star system, using the effect of gravitational wobble to detect the planet's presence.
3. We don't know much about its star.
The Proxima Centauri star is a red dwarf, an M-class star that's in a binary star system. It has a much brighter partner, Alpha Centauri AB, and we have little familiarity with these stars. The great thing about red dwarves are that they are long-lived. They are also much cooler and so are more difficult to study, especially with a star system when one outshines the other greatly.
4. There could be various challenges with living there.
Everything from magnetic fields to X-rays to tidal locks could be a challenge, assuming there's liquid water on the planet. Plus, it'd take us 18,447 years to arrive at our current technologies. Until the starship Enterprise is realised, we'll be spending more time making sure we don't become Venus.