In recent years, the number of discoveries regarding new planetary systems has been on the rise.
Some of these systems may potentially harbor life, prompting space superpowers and private companies to reignite their search for extraterrestrial life.
Exoplanet 51 Pegasi b was discovered in 1995 within our galaxy. Prior to this, humans had no knowledge of celestial bodies existing outside our solar system.
According to astronomers, the existence of a planet with life beyond Earth is no longer a concept of science fiction (Image credit: National Geographic).
In fact, scientists were uncertain whether any planets existed outside the Solar System. In this context, imagining extraterrestrial life seemed purely fictional. However, a surprise occurred when astrophysicists discovered that 51 Pegasi b is a gigantic planet “squeezed” tightly by its star, with an orbital period of just 4 days.
To date, humanity has discovered over 4,000 exoplanets, yet the physical laws governing these celestial bodies differ significantly from those we know on Earth. For instance, some exoplanets orbit their stars within mere hours, while others take up to a million years. Some orbit two stars, while others wander alone in the vastness of space.
More than half of these were discovered thanks to the Kepler Space Telescope, launched into space in 2009. Kepler was tasked with discovering as many planets as possible. The telescope sought planets orbiting 150,000 stars in a small patch of the sky – roughly the area covered by your hand if you stretched your arm out in front of you and pointed it towards the sky.
However, the project’s ambitions extended far beyond simple discoveries. Most importantly, Kepler was part of a larger mission to find planets that could potentially support life. When “the eyes” of Kepler concluded its mission in October 2018, it had identified 2,662 exoplanets, with at least a quarter of these being Earth-sized and located in habitable zones. These regions have conditions that are neither too hot nor too cold for life.
There are at least 100 billion stars in our galaxy (the Milky Way), and at least 25 billion of these planets could be “homes” where life may arise. However, the Milky Way is just one galaxy among trillions within the vast universe.
Thanks to the information provided by the Kepler telescope, the question is no longer whether extraterrestrial life exists, but rather how we can find it. Kepler’s revelations about our galaxy, filled with numerous planets, have sparked the search for life in the universe. Many private space companies have invested billions of dollars into observation programs aimed at finding extraterrestrial life.
All efforts are directed towards one main goal: seeking signs of life, regardless of its form on other planets. The advancement of technology, as well as substantial funding from organizations and governments for space missions, has further propelled the quest for extraterrestrial life.
It is hoped that in the future, humanity will receive more positive signs regarding this matter, particularly concerning planets with environmental conditions suitable for human existence. Especially in a world facing climate change, with numerous warnings about habitat loss, the prospect of relocating humanity to another planet for habitation is increasingly becoming a reality.
However, significant obstacles remain in studying exoplanets; many celestial bodies situated in habitable zones are very close to their stars, resulting in a tidal locking phenomenon for their orbits. This is akin to the Moon in relation to Earth, where we can only observe one illuminated side of the Moon, while the dark side remains a complete mystery.
Consequently, many countries are striving to send probes to explore the dark side of the Moon. Recently, China became the first country in the world to successfully return samples from this planet and is on its way back to Earth. Scientists speculate that the dark sides of exoplanets may present extreme temperature conditions, making it hard to imagine that life could develop there, except perhaps at the boundary between the two regions (the light side and the dark side).
