The universe has remained so huge and mysterious and interesting. Among all those terrors, which might include the exoplanets or planets orbiting other stars outside our Solar System, Thus, this single fact has made them pursue an earthlike world amongst them too captivating for any scientist and a dreamer who wonders if life on Earth may be everywhere else in those faraway stars. Maybe someday, they could be the future home of humans. Exoplanets are planets that orbit other stars outside our solar system. This article shall touch on the brilliant journey of the discovery of exoplanets and their possibility of being Earth-like.
Otherwise known as an extrasolar planet, an exoplanet is any planet that orbits any other star than the Sun within our solar system. That all changed in 1992 with the first confirmed detection of an exoplanet, where astronomers detected two planets orbiting a pulsar—a rapidly spinning neutron star. Those planets were not hospitable to life, however. It wasn’t until 1995 that a planet in orbit around a main-sequence star was confirmed, and with improved technology and tireless work by astronomers around the world, the discovery of thousands of exoplanets has been made to date.
How Do We Find Exoplanets?
Finding exoplanets is not particularly easy. For one thing, they are exceedingly distant and almost always behind the bright light of their parent star. To work around such hassles, astronomers have concocted several ingenious techniques:
1. Transit Method: Probably one of the most successful techniques, it monitors the star’s light for periodic diminutions of brightness that could indicate the transit of a planet in front of it. It is with this very method that thousands of exoplanets were revealed by NASA missions like Kepler and TESS.
2. Radial Velocity Method: This is a method by which one measures the gravitational “wobble” of a star caused by tugs from a planet in orbit about the star. It works extremely well in finding large planets close in to their stars.
3. Direct Imaging: Quite impossible to obtain because they are normally very faint and quite near some brilliant stars. Nowadays, better telescopes along with imaging skills have made such a thing realistic for bigger-sized planets, though.
4. Gravitational Microlensing: This technique is based on the gravitational field of a heavy object being used to focus light coming out from a star that lies in its background. It may even allow the identification of planets across the foreground object.
All these techniques combined keep updating the list of exoplanets and bring us closer to understanding the universe a little better.
What Is an Earth-like Exoplanet?
They are not all equal in terms of hosting life possibilities. In other words, besides what has been mentioned, an Earth-like planet needs to drop into what many people call the habitable zone. It is that zone around a star where conditions might allow, for the very first time, liquid water to be on the surface of some certain planet. As we know, liquid water is one of the major ingredients of life.
The Earth-like planets must be rocky in nature and with mass as similar to that of Earth as what the Earth needs, but so far as the gas giants are concerned, they are not at all apt for life. Jupiter and Saturn being some examples.
Atmosphere: It has to be stable enough to retain life on it, or it also has to safeguard against lethal radiations so that temperature gets regulated on the surface.
– Stable Star: The star with the exoplanet should be stable and long-lived. Too active or
Some Notable Earth-like Exoplanets
Few exoplanets have been termed as potentially earth-like. Few of these are
1. Kepler-452b: This was termed as Earth’s cousin lying in the habitable zone of a star almost identical to the Sun. It has been estimated to be about 1.6 times bigger than Earth and is of rocky composition.
2. Proxima Centauri b: This exoplanet orbits the nearest star to the Sun, Proxima Centauri. It lies within its star’s habitable zone, yet it is still debated with respect to whether it could host life on it since the star is very active.
3. TRAPPIST-1 comprises seven Earth-sized planets. Three of the planets are well within what is called the habitable zone of the star. Given the proximity among themselves and to the star, it has become unique among the follow-up targets.
4.1140b—This LHS 1140b—This is one of the most promising terrestrial candidates discovered to date for atmospheric characterisation, a rocky planet sitting in the habitable zone of a nearby red dwarf star.
Why Find Earth-like Planets?
While searching for an Earth-like exoplanet, generally speaking, there is a following reason:
1. Life Understanding: Locating the planets that could support life will help in understanding those conditions that will eventually provide life.
2. Expansion of Knowledge: The detection of Earth-like planets extends our knowledge of the planetary system and their diversities.
3. Future Emigration: Considering Earth is facing lots of problems arising due to climatic and population explosion, such a viable twin would serve as an option for humankind—Plan B—at some point in the future.
4. Scientific Curiosity: Some find the excitement related to exoplanets rather overwhelming to answer questions such as “Are we alone in the universe?”.
Challenges and Future Prospects
Despite these spectacular successes, the study of the exoplanets carries lots of specific complications:
• Distance: Most of the exoplanets happen to be light-years away, thus making the detailed observation quite impossible.
• Technological Limitations: Present instruments are faulty in detecting small or Earth-sized planets, especially those that tend to stay farther away from their stars.
– Complexity of Life: Besides all that, a planet literally just has to meet every habitable criterion to start with life there—which again is a major challenge.
The near-future prospects are good, with to-be-launched telescopes like the James Webb Space Telescope, but even more so ESA’s ARIEL mission, coming for the first time with revolutionary capabilities in the quest to characterise exoplanetary atmospheres in parallel searching for biosignatures. Big leaps ahead can also come from next-generation ground-based facilities.
In conclusion, presently, one of the most heated peripheries in the domains of modern astronomy deals with or takes place over searching for earth-like planets. Closer it gets, with every discovery, to finding a place in the universe, maybe for life. Whether it will ever lead to an Earth twin is a bold adventure, proving that the human mind is full of curiosity and intellect. We can always look up towards the stars and contemplate the infinite possibility that exists within the universe, yet so few things we’ve truly understood or could ever comprehend.
