Humanosity says…We are on the brink of providing an answer to one of humanity’s oldest questions – are we alone in the Universe. Space telescopes have found 1000s of planets around other stars but now they are starting to find planets that bear similarities to our own. This article details the latest discovery of water on a potentially habitable planet…
According to details were published in the journal Nature Astronomy the planet was found orbiting a star 124 light-years away. So far some 4000 planets have been discovered orbiting stars and the unimaginatively named K2-18b was one of a set of planets discovered by the Hubble and the Kepler telescopes.
The team then examined changes to the light coming from the star that passed through the planet’s atmosphere. Based on these observations came to the conclusion that one of the chemicals present in the planet’s atmosphere was water.
Red Dwarves and The Habitable Zone
K2-18b takes 33 days to orbit its star, a type of star called a red dwarf or M-type star. These are the most numerous types of stars in the universe, making up around 70% of all-stars. They are much smaller than our sun and much cooler. Being less bright makes it easier for astronomers to detect planets that orbit this class of stars.
The habitable zone of a star is the band around a star where the temperature is just right to allow water to exist in its liquid form. Because these stars are much cooler than our sun this means the habitable zone is much closer to the star.
Dr Angelos Tsiaras, an astronomer on the UCL team that made the discovery, said that finding water in the atmosphere of a “potentially habitable exoplanet was incredibly exciting”.
However, the finding has been challenged by other astronomers who suggest that the planet is too big to be habitable. They say that the planet is much more massive than the Earth and should instead be thought of as more like a mini Neptune. This matters because current theories suggest that planets this big are unlikely to have a rocky surface.
Just what makes a planet habitable or not is still open to question as we only have the Earth as a guide. The Earth has liquid water, oxygen and ozone and the next generation of telescopes like the James Webb telescope being built by NASA will be able to detect these chemicals in the atmospheres of distant planets.
“This is one of the biggest questions in science and we have always wondered if we are alone in the Universe,” Dr Waldmann said. “Within the next 10 years, we will know whether there are chemicals that are due to life in those atmospheres……