Ross 128: Why the newly discovered planet could be our best hope for finding alien life

Something new and very exciting has just moved into our neighbourhood

The new exoplanet, known as Ross 128 b, is the size of our own Earth (ESO/M Kornmesser)

We might just have spotted our new home – or someone else's.

A newly discovered star, known as Ross 128 b, has been held up as our most likely neighbour that could support life. And conditions there look much nicer than the other stars in our neighbourhood.

That has led to excitement across the world amid the possibility that we've found an entirely new one. If we have, it'll not only offer the potential to see what another planet like our own looks like – but potentially to meet the aliens that live there, or to move there ourselves.

Why are people so excited about Ross 128 b?

Because it looks a lot like us. And if it is like us, then it's likely to be both a decent place for aliens to potentially live, and a possible future home for ourselves.

The obvious things are that the planet is roughly the same size as ours, and might have a similar climate.

But what has got people especially excited is its star, Ross 128. That's a red dwarf – a type of sun that offers hope to scientists looking for exoplanets, but comes with some caveats.

Red dwarfs are good because they are cooler and more comfortable than our own star. That not only means that any life that is supported by them is more likely to flourish on planets that are closer, but it also means that they're easier for us to see, because there's not such a bright sun in the way.

Many of them throw out intense bursts of radiation and solar wind that would fry anything that tried to live on planets supported by them. But what's remarkable about Ross 128 is that it is especially calm and comfortable – it doesn't seem to be given to such outbursts, meaning that the chance of supporting life on the planet is vastly increased.

How does it compare with other exoplanets?

Many of the other candidates for nearby Earth 2s suffer from those problems.

Proxima Centauri b, for instance – which is just four lightyears away – orbits around its own red dwarf. But that star is a lot more temperamental, and throws out radiation that makes the conditions very unlikely to be able to support life, or at least like anything on Earth.

How did we spot it?

Ross 128b was spotted by a highly successful planet-finding instrument attached to the European Southern Observatory's 3.6-metre telescope at La Silla, Chile.

The High Accuracy Radial Velocity Planet Searcher (Harps) looks for tiny wobbles in a star's motion caused by its gravitational interaction with planets orbiting it.

The "tug-of-war" between star and planet is revealed in shifts in the wavelengths of light emitted by the star. From these readings, astronomers can make calculations about a planet's mass and orbit.

What do we do next?

While Ross 128b is considered to be a "temperate" planet, astronomers are still not certain where it lies in relation to its star's habitable zone.

Within the next 10 years, a new generation of ultra-powerful telescopes will start studying the atmospheres of exoplanets looking for signs of life, such as oxygen.

They include the ESO's 39-metre Extremely Large Telescope under construction in Chile which is due to begin operating in 2024.

Haven't I heard of Ross 128 before?

Maybe. This is the plucky star's second time in the spotlight this year.

Earlier this year, scientists said that they had received strange pulses coming from the star. The unusual signals didn't seem to have any sensible explanation, they said, and they committed to do further work.

But that further work suggested that the signals were just interference, and there wasn't anything coming from the star (or aliens living near it) at all. This time around, the news is a little more clear and certain, even if more work is still to be done.

Additional reporting by agencies