An artistic concept of the planet
Recent scientific developments point to the existence of an Earth-size planet orbiting the closest star to the Sun: Proxima Centauri (4.2 light years, 26 Trillion miles). The planet is at the right distance to its star to have liquid water, the essential element of life as we know it. This area which is not to close, but not too far from the sun is called the Goldilocks Zone.
Part of the Pale Red Dot initiative, scientists, have been observing the Proxima Centauri star in search of evidence of a planet. Because planets are usually tiny in relation to their star, and because the star tends to overwhelm any light-based sensors we have, it is very hard to actually “see” a planet.
There are several methods for detecting planets. One consists of looking at regular drops in the level of brightness of the star, which may indicate that something in orbit is passing in front of it. The other is to look at a wobble of the star, which would be caused by the gravity attraction between the star and the planet (the planet also pulls the star towards itself).
This wobbling motion of the star is probably induced by a nearby planet
It is this gravity-induced wobbling that leads scientists to establish a “fingerprint” of a planet, saying that this was strong evidence that something estimated to have 1.3X the mass of Earth was orbiting this star. According to the readings, the planet would orbit around its star every 11.2 days.
This means that the planet is extremely close to its sun when compared to Earth. However, Proxima Centauri is also much dimmer than the Sun, so the Goldilocks Zone is located closer as well. Before you get too excited, it should be said that although the conditions on the planet should allow for liquid water to exist, there’s also a good chance that the short distance to the sun makes the planet’s surface very exposed to solar radiations (X-Rays, UVs…). It’s just hard to tell.
Also, it is unclear at the moment if the planet’s surface has half of it always oriented towards the sun, or if it has a rotation which would distribute the solar exposure more evenly. In short: we need more direct observations, although it will take a very long time for a human satellite to reach that location: an estimated 81,000 years with current technologies. Although space may become key to our survival at some point, this new discovery is only one (very) tiny step towards space colonization.