Researchers are particularly fascinated by these exoplanets.

In recent decades, research has found thousands of exoplanets and gained insights into potentially habitable worlds.

Frankfurt – The search for signs of life in the universe is not over yet. For the first time, there are now signs that there is a chance to find traces of life outside our solar system. Thanks to exoplanet research, more than 5,000 potentially habitable planets have been discovered in the past few decades. And this number is constantly growing.

Experts now assume that there are more planets in our galaxy than stars. From hot, gas giants to unimaginably cold worlds and even life-friendly celestial bodies, every type is represented. But all exoplanets have one thing in common: They offer countless insights into the universe.

These exoplanets fascinate science and give researchers many ideas:

1. HD 28185 B: A major milestone in exoplanet research was the identification of this giant planet, which lies in the so-called habitable zone. This zone covers the area where temperatures could theoretically be suitable to sustain liquid water permanently. However, this supposedly life-friendly exoplanet is a gas giant with no solid surface and is about six times the mass of Jupiter.
2. Trappist System-1: The recent discovery of a complete planetary system around the dwarf star Trappist-1 is particularly interesting for astrobiology. The system is located about 40 light-years from Earth and consists of at least seven Earth-sized planets. There is a possibility that some of these planets could host liquid water, with three of them located in the star’s habitable zone, where conditions could be favorable for life to emerge.
3. Inner Circle of Trappist-1: New instruments, such as the James Webb Space Telescope, are allowing for more precise analysis of distant worlds. Recently, an international team of researchers examined the innermost of the seven TRAPPIST planets using the Webb telescope. They discovered that this planet has no atmosphere, and is closer to our innermost planet, Mercury.
4. HD 209458 B: Although the conditions on this gas giant are too harsh for life, they are even more important for research. In 1999, it was discovered as the first exoplanet to be discovered using the transit method. This method looks at the gradients in brightness that occur when a planet passes in front of its star from our perspective. Since this groundbreaking discovery, scientists have not only been able to prove the existence of exoplanets, but also to draw conclusions about their size and orbit.
5. Kilt-9B: Kelt-9b is the hottest exoplanet known to date. Because of its location, the day side of this exoplanet is exposed to intense radiation, reaching temperatures of about 5,000 degrees Celsius. It is located about 650 light-years from Earth and completes an orbit around its star in just 36 hours. Even on the exoplanet's night side, temperatures do not drop below 2,500 degrees Celsius.
6. 51 Pegasus B: In 1995, Swiss astronomers Michel Mayor and Didier Queloz discovered this exoplanet in the spectrum of a Sun-like star. This groundbreaking discovery earned them the 2019 Nobel Prize in Physics. The exoplanet is located about 50 light-years from Earth and is similar in structure to the gas giant Jupiter. Despite its proximity to Earth and its Sun-like star, this planet is not at all friendly to life, with a surface temperature of 1,000 degrees Celsius.
7. Glaze 667cc: The exoplanet is just 22 light-years away from Earth and is said to be at least 4.5 times larger than our own, according to NASA. The planet orbits its star in just 28 days. However, its star is much cooler than our Sun. For this reason, scientists suspect that the planet may be in the habitable zone. However, there is a chance that Gliese 667Cc is close enough to its star to burn with its own flames.
8. Kepler: When NASA’s Kepler space telescope launched in 2009, it marked a milestone in space exploration. During its nine-year mission, Kepler researchers were pleasantly surprised to find evidence of more than 2,600 exoplanets. A prime example is Kepler-186f, which in 2014 was identified as the first Earth-like exoplanet in the habitable zone. Although the exoplanet is closer to its star than Earth is to the sun, its smaller size could mean it has favorable conditions, such as temperatures, seasons, and a stable climate conducive to life.
9. Kepler-452b: In 2015, the Kepler telescope encountered a fascinating exoplanet. This planet is about 1.6 times more massive than Earth and orbits a sun-like star. Its orbit, which is about the same length as an Earth year and lasts 385 days, could provide conditions that are suitable for life and liquid water. It is also possible that this celestial body is a kind of hot Venus due to its strong greenhouse effect.
10. Exoplanet No. 5000: Exoplanet research reached a major milestone in March 2022 with the discovery of the 5,000th confirmed exoplanet by NASA. This number shows how rapidly the field of research is evolving and becoming increasingly rich in results.

The latest findings suggest that there may be another planet in our solar system.

What are the critical criteria when searching for an exoplanet suitable for life?

Our Earth is currently the only planet in our solar system that contains water in all physical states. Water in liquid form is particularly important. Earth's location also plays a crucial role. If it were just 3% closer to the Sun, the water would evaporate.

The arrangement of the planets in our solar system is also important. Researchers believe that exoplanets are protected from interplanetary collisions by their high gravity. In addition, a potentially habitable planet would have to be about the same size as Earth. A smaller size would result in lower air pressure and less oxygen. And if the planet is too big, gravity could be too strong, which could limit the freedom of movement of living organisms. Currently, only 20 exoplanets are considered to have potential life, according to NASA. mentioned. (CG)