Exoplanet ‘remarkably similar to Earth’ could be habitable, NASA says

It’s one of the biggest unanswered questions in science: are there aliens out there, and if so, where are they hiding?

Now, a discovery by NASA has raised the tantalising possibility that we’re not alone after all. 

The US space agency has discovered an exoplanet 146 light-years away that is ‘remarkably similar to Earth’. 

Dubbed HD 137010 b, the planet might fall just within the outer edges of its star’s ‘habitable zone’, meaning there could be liquid water on its surface and a suitable atmosphere for life. 

However, any potential aliens living on this planet would need to be well adapted for cold weather. 

‘Although of a stellar type similar to our Sun, the star, HD 137010, is cooler and dimmer,’ NASA explained. 

‘That could mean a planetary surface temperature no higher than -90°F (-68°C).

‘By comparison, the average surface temperature on Mars runs about -85°F (-65°C).’

NASA’s scientists discovered the rocky exoplanet using data gathered by the Kepler Space Telescope.

This discovery comes from a single ‘transit’ – the planet crossing its star’s face – which was detected during Kepler’s second mission, K2. 

While one transit doesn’t sound like much, this was enough for the scientists to estimate the exoplanet’s orbital period. 

By tracking the time it took for the planet’s shadow to move across its sun’s face, the team estimated that the planet has an orbital period of 10 hours, compared to Earth’s 13 hours. 

Their calculations also suggest it’s probably freezing, although there is a chance HD 137010 b could turn out to be a temperate or even a watery world, according to NASA. 

‘It would just need an atmosphere richer in carbon dioxide than our own,’ the team explained. 

Based on modelling of the planet’s possible atmospheres, NASA says there is a 40 per cent chance that the planet falls within the ‘conservative’ habitable zone around the star, and a 51 per cent chance that it falls within the broader ‘optimistic’ habitable zone.

‘The planet has about a 50–50 chance of falling beyond the habitable zone entirely,’ the experts cautioned. 

To confirm whether or not the planet is habitable, the researchers will now conduct follow-up observations – although they admit this is going to be ‘tricky’. 

‘The planet’s orbital distance, so similar to Earth’s, means such transits happen far less often than for planets in tighter orbits around their stars – it’s a big reason why exoplanets with Earth-like orbits are so hard to detect in the first place,’ NASA explained. 

‘With luck, confirmation could come from further observation by the successor to Kepler/K2, NASA’s TESS (the Transiting Exoplanet Survey Satellite), the still-functioning workhorse for planetary detection, or from the European Space Agency’s CHEOPS (CHaracterising ExOPlanets Satellite).

‘Otherwise, gathering further data on planet HD 137010 b might have to wait for the next generation of space telescopes.’

KEY DISCOVERIES IN HUMANITY’S SEARCH FOR ALIEN LIFE

Discovery of pulsars

British astronomer Dame Jocelyn Bell Burnell was the first person to discover a pulsar in 1967 when she spotted a radio pulsar.

Since then other types of pulsars that emit X-rays and gamma rays have also been spotted.

Pulsars are essentially rotating, highly magnetised neutron stars but when they were first discovered it was believed they could have come from aliens.

‘Wow!’ radio signal

In 1977, an astronomer looking for alien life in the night sky above Ohio spotted a radio signal so powerful that he excitedly wrote ‘Wow!’ next to his data.

The 72-second blast, spotted by Dr Jerry Ehman through a radio telescope, came from Sagittarius but matched no known celestial object.

Conspiracy theorists have since claimed that the ‘Wow! signal’, which was 30 times stronger than background radiation, was a message from intelligent extraterrestrials.

Fossilised Martian microbes

In 1996 Nasa and the White House made the explosive announcement that the rock contained traces of Martian bugs.

The meteorite, catalogued as Allen Hills (ALH) 84001, crashed onto the frozen wastes of Antarctica 13,000 years ago and was recovered in 1984. 

Photographs were released showing elongated segmented objects that appeared strikingly lifelike.

However, the excitement did not last long. Other scientists questioned whether the meteorite samples were contaminated. 

They also argued that heat generated when the rock was blasted into space may have created mineral structures that could be mistaken for microfossils. 

Behaviour of Tabby’s Star in 2005 

The star, otherwise known as KIC 8462852, is located 1,400 light years away and has baffled astronomers since being discovered in 2015.

It dims at a much faster rate than other stars, which some experts have suggested is a sign of aliens harnessing the energy of a star.

Recent studies have ‘eliminated the possibility of an alien megastructure’, and instead, suggests that a ring of dust could be causing the strange signals.

Exoplanets in the Goldilocks zone in 2017 

In February 2017 astronomers announced they had spotted a star system with planets that could support life just 39 light years away.

Seven Earth-like planets were discovered orbiting nearby dwarf star ‘Trappist-1’, and all of them could have water at their surface, one of the key components of life.

Three of the planets have such good conditions, that scientists say life may have already evolved on them. 

Researchers claim that they will know whether or not there is life on any of the planets within a decade, and said: ‘This is just the beginning.’