Within our vast universe, the Earth is only one dot in comparison to the of countless other planets. However, our endeavors to find other worlds similar, or different, to our own continue each and every year, as we are captivated by the idea of otherworldly life. Currently, scientists, using cutting-edge technology, are discovering new planets and stars every year, both (relatively) near and far, at an incredible rate. I’m going to dive into just how these astronomers go about doing this and what their hopes are regarding extra-terrestrial life.

How do we find exoplanets?

Exoplanets is the name given to planets which orbit stars outside of our solar system. Discovering them can be quite difficult as they can be obstructed by the light of their host star or can be too far away to view easily. However, scientists have developed a range of different techniques to detect them nonetheless:

  • Transit Method: The process of observing the light emitted from a star and seeing if there are any dips in its brightness for when a planet may pass in front of it. This technique not only confirms the presence of a planet but also information such as its size and orbit which makes it obvious to why it’s the most common method used.
  • Radial Velocity Method: The method of measuring the variations in speed that a star moves towards/away from us. This is caused by the gravity of the orbiting exoplanet and also offers insights into its mass.
  • Direct Imaging: The picturing of planets themselves, by blocking out the light from the host star. It is particularly useful for large exoplanets with large orbits but it can be quite a challenging technique to use.

Possibility of alien life

With over 4,000 exoplanets discovered so far, the chances that alien life is out there seem exciting. The forefront of this research comes from finding planets similar to our own (i.e. rocky planets within a habitable orbit of their star), where liquid water can be found, as it is a crucial part of life as we know it. The discovery of these types of exoplanets has sparked interest and further research into the topic of potential life, as planets in the TRAPPIST-1 system (approx. 40 light years away) are thought to have temperate climates that could possibly support liquid water and therefore life [Gillion, 2017].

The Next Step

Missions like the James Webb Space Telescope (JWST) pose a bright future for the discovery of exoplanets and hope to provide us with a greater understanding of these worlds and their atmospheres. By analysing the gases present on these planets, JWST might help us detect biological activity which may just indicate extraterrestrial life. As we continue to improve technology and discover more of the cosmos, the odds of an Earth-like planet showcasing signs of life are becoming more and more likely. Through the study of these exoplanets we are getting closer to answering the age-old question; Are we alone in the universe?


  • Gillon, M., Triaud, A., Demory, BO. et al.Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1. Nature 542, 456–460 (2017).
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