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Are we alone? This question is almost as old as humanity itself. Today, this question in astronomy focuses on the search for life beyond our planet. Are we
Are we alone? This question is almost as old as humanity itself. Today, this question in astronomy focuses on the search for life beyond our planet. Are we alone as a species and as a planet? Or is there life elsewhere?
Often this question inspires visions of strange, green versions of people. But life isn’t just about us: animals, fish, plants and even bacteria are all kinds of things we seek out in space. Life on Earth leaves traces in the chemical composition of the atmosphere. So what we look for when hunting aliens are traces that can be seen from afar.
Scientists from the United Kingdom and the United States have reported that there are some very interesting chemical signatures in the atmosphere of a planet called K2-18b, about 124 light-years away from Earth. In particular, they were able to detect a substance produced only by living things on Earth.
K2-18b is an interesting exoplanet; A planet orbiting another star. Discovered by the Kepler space telescope’s K2 mission in 2015, this planet is a type of planet called sub-Neptune. As you can imagine, they are smaller than Neptune in our solar system.
The planet is about eight and a half times more massive than Earth and orbits a red dwarf-type star that is much cooler than our Sun. However, K2-18b orbits much closer to its star than Neptune, in what we call the habitable zone. A place that is neither too hot nor too cold, where liquid water can be found (rather than freezing to ice or boiling to steam). Earth has been called a rocky planet (for obvious reasons), but sub-Neptunian planets are hydrogen- and helium-rich gas planets with much larger atmospheres. Their atmospheres may also contain other elements.
This brings us to the excitement surrounding K2-18b.
The planet was first discovered by the Kepler space telescope, which was observing distant stars and hoping for planets to pass in front of them. When the planet passes between us and the star, the star becomes dim for a moment; This tells us about the existence of the planet.
By measuring how large the drop in brightness is, how long it takes for the planet to pass in front of the star, and how often this happens, we can determine the planet’s size and orbit. This method is great for finding planets, but it doesn’t tell us about their atmospheres; This is an important piece of information to understand whether they are life or habitable.
NASA’s James Webb Space Telescope (a large space telescope set to launch in late 2021) observed and measured the exoplanet’s atmosphere. The telescope did this by measuring the color of light so precisely that it could detect traces of specific atoms and molecules. This process, called spectroscopy, is similar to measuring the fingerprints of elements.
Each element and molecule has its own color signature. If you can look at the color signature, you can determine which elements or compounds are present on the planet by doing a little detective work. Although the planet has no light of its own, astronomers waited for K2-18b to pass in front of its star and measured the starlight as it passed through the planet’s atmosphere, allowing the team to detect traces of matter in the atmosphere.
The new study found a lot of carbon dioxide and methane. This is interesting because it resembles Earth, Mars and Venus in our solar system, not Neptune. But it also detected small amounts of dimethyl sulfide. Dimethyl sulfide is an interesting molecule composed of carbon, hydrogen and sulfur.
The world in general is a bit stinky. But it is also closely related to life. The only process we know of for the formation of dimethyl sulfide on our planet is life. Especially marine creatures and plankton secrete it in gaseous form. So yes, scientists are excited about the idea of ​​alien sea farts. If it’s real. And it is connected to life.
Although dimethyl sulfide is associated with life on Earth, it may be associated with geological or chemical processes in some way on other planets. After all, K2-18b is something like Neptune, a planet we don’t know much about. Last month, researchers discovered that clouds on Neptune are closely related to the Sun’s 11-year activity cycle. We have a lot to learn about planets and their atmospheres.
Additionally, measurement of dimethyl sulfide is very sensitive; It is not as strong as carbon dioxide and methane. This means more detailed measurements are needed to increase signal strength. Other telescopes may need to join this effort. Instruments on the Very Large Telescope in Chile can also measure the atmospheres of planets around other stars, as can a new instrument called Veloce on the Anglo Australian Telescope at Siding Spring Observatory in Australia.
New space telescopes like Europe’s under-construction PLATO will also help us get a better look at alien atmospheres. So, although the dimethyl sulfide signature on K2-18b is not associated with life, it is still an exciting possibility. There’s still much to discover. Source
Source: Port Altele
As an experienced journalist and author, Mary has been reporting on the latest news and trends for over 5 years. With a passion for uncovering the stories behind the headlines, Mary has earned a reputation as a trusted voice in the world of journalism. Her writing style is insightful, engaging and thought-provoking, as she takes a deep dive into the most pressing issues of our time.
