Context: The European Space Agency (ESA) has formally adopted Ariel - Atmospheric Remote-sensing Infrared Exoplanet Large-survey, which scientists are planning to launch in 2029.

More on the news:

  • As of now the existence of more than 4,000 exoplanets is considered confirmed, while there are thousands of other candidate exoplanets that need further observations.
  • Proxima Centauri b is the closest exoplanet to Earth and is four light-years away and inhabits the “habitable zone” of its star, which means that it could possibly have liquid water on its surface.

About Ariel Space Mission:

  • Need: According to the ESA, while a large number of exoplanets have already been discovered, there is no clear link between the presence, size or orbital parameters of the planet and the nature of their parent stars. 
  • A large-scale survey: The explorer will perform a large-scale survey of over a thousand exoplanets over a period of four years that will help in studying the nature, formation and evolution of exoplanets.  
    • Ariel is the first of its kind mission dedicated to measuring the chemical composition and thermal structures of hundreds of exoplanets. 
    • Further, Ariel will help to answer one of the key questions of ESA’s Cosmic Vision Plan - What are the conditions for planet formation and the emergence of life?.

About exoplanets:

  • Lie outside the solar system: Planets that lie outside of the Solar System and orbit around stars other than the Sun are called exoplanets or extrasolar planets. 
  • Not easy to detect: Since they are much less brighter than the stars they orbit and hence it is difficult to see them directly using telescopes.
  • Methods to detect exoplanets: Only a handful of exoplanets have been found using telescopes and the rest have been detected using indirect methods, such as, 
    • Tracking the dimming of a star: That happens when a planet passes in front of it. NASA’s Kepler Space telescope uses this method to spot thousands of planets.
    • Gravitational lensing and the wobbling method: Which is based on the idea that an orbiting planet will cause its parent star to orbit slightly off-centre.

Significance of studying exoplanets:

  • Possibility of existence of life beyond Earth: Scientists believe that the hunt of exoplanets will reveal details about where humans came from and where we are headed.
  • Teaches a little bit more about how the universe works: And how the Earth, Sun and own planetary system fit into the whole.

Image Source: IE