Water on Another Planet

Water on Another Planet – May Be A Potentially Habitable Super-Earth

Astronomers have now, for the first time, discovered water in the atmosphere of a planet which is orbiting within a habitable zone of a distant star.

The study finding makes the world – which is called K2-18b – a plausible candidate in the search for alien life.

Within ten years, new space telescopes might be able to determine whether K2-18b’s atmosphere contains gases that could be produced by any living organisms.

The details of the study were published in the journal Nature Astronomy.

Prof Giovanna Tinetti of University College London, the lead scientist, described the discovery of water on another planet as mind-blowing.

She said that this is the first time that researchers have detected water on a planet in the habitable zone around a distant star where the temperature is potentially compatible with the presence of life.

The potentially habitable zone is the region around a distant star where the temperatures are sufficiently benign for water to exist in its liquid form on the surface of a planet.

The K2-18b is 111 light-years i.e, about 650 million million miles from Earth, too far to send a probe. Then the

only option left is to wait for the next generation of space telescopes which is to be launched in the 2020s and also to look for those gasses in the planet’s atmosphere that could only be produced by any living organisms, according to UCL’s Dr. Ingo Waldmann.

Dr. Waldmann said that this is one of the biggest questions in science and researchers have always wondered whether we are alone in the Universe. Within the next 10 years, we will know whether there are chemicals that are due to life in those atmospheres, Waldmann added.

Exoplanets- What are they?
  • Planets that are beyond our Solar System are called exoplanets
  • The first exoplanet was discovered in the year 1992, orbiting a pulsar i.e, a neutron star that emits electromagnetic radiation.
  • More than 4,000 exoplanets have been detected to date.
  • Many of these worlds are large planets believed to be like Jupiter or Neptune planets.
  • Many of the giant planets have been found orbiting very close to their stars

The research team behind the discovery looked through the planets discovered by the Hubble Space Telescope between the years 2016 and 2017. The scientists determined some of the chemicals in their atmosphere by studying the changes to the starlight as the planets orbited their suns. The light filtered through the planet’s atmospheres was subtly altered by the composition of the atmosphere.

Only K2-18b revealed the molecular signature of water- is a vital ingredient for life on Earth. Computer modeling of the data suggested that up to fifty percent of its atmosphere could be water.

The new planet is just over two times the size of Earth and has a temperature cool enough to have liquid water between 0 and 40C.

Dr. Angelos Tsiaras who is a member of the UCL team said that finding water on another planet or say in the atmosphere of a potentially habitable exoplanet was incredibly exciting.

He said that it brings us closer to answering the fundamental question! Is the Earth unique?!!

One difficulty with this approach is that astronomers can’t agree on which gases would constitute evidence of life. That might be more of a long haul.

And it is likely to require a survey of the chemical composition of, perhaps,100s of worlds and an understanding of how these are created and evolved, according to Prof Tinetti.

Our Earth is a planet that really stands out in our own Solar System. It has oxygen, water, and also ozone. But if we find all of these around a planet around a distant star we have to be very cautious about saying that it supports life, she added.

She said that this is why we need to understand not just a handful of planets in the galaxy but hundreds of them. What we all hope is that the habitable planets will stand out, that we will see a big difference between the planets that are habitable and the ones that are not.

Dr. Beth Biller of Edinburgh University’s Institute of Astronomy said she believed that the evidence of life on a planet around a distant star would eventually be discovered and this would be a paradigm shift for all of humanity, Biller told BBC News.

She added that it’s not going to be ET phoning home, necessarily more likely microbes or any other simple life. Even so (when it happens) it is going to be huge.

Nasa’s prospective launch much delayed James Webb Space Telescope (JWST) in the year 2021, and the European Space Agency‘s Ariel mission seven years later will enable astronomers to study in detail the atmospheres of the varied worlds that have been detected so far.

Formerly, water has been detected on other planets. Water has been detected on planets which are either too big or too hot to support life. The cooler smaller planets are much harder to detect. The research team at UCL was able to do this by developing algorithms that were capable of teasing out the chemical compositions of the atmospheres of potentially habitable worlds.

The K2-18b was discovered in the year 2015 and is one of the hundreds of super-Earths i.e, those planets with a mass between Earth and Neptune planets was found by Nasa’s Kepler spacecraft. The Tess mission of Nasa is expected to detect hundreds more in coming years.

The research study was funded by the European Research Council and the UK Science and Technology Facilities Council. This council is a part of the UK Research and Innovation agency (UKRI).


Ria Roy
Ria Roy completed her Post Grad degree at the Visvesvaraya Technological University. She has a great grounding in the skills, including technical, analytical and research skills. She is a motivated life science professional with experience of working in famous research institutes