ARIEL Space Mission of Europe Space Agency.
                     ARIEL Space Mission of Europe 
Space Agency
INTRODUCTION
– The European Space Agency (ESA) has formally 
adopted Ariel, the explorer that will study the 
nature, formation and evolution of exoplanets.
– 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.
Source: indianexpress.com
Proxima Centauri b 
– 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.
Source: indianexpress.com
What are exoplanets?
– Planets that lie outside of the Solar System and 
orbit around stars other than the Sun are called 
exoplanets or extrasolar planets.
– Exoplanets are much less brighter than the stars 
they orbit and hence it is difficult to see them 
directly using telescopes.
Source: www.iasgyan.in
Detection of exoplanets
– Only a handful of exoplanets have been found 
using telescopes and the rest have been 
detected using indirect methods.
– One of these methods involves tracking the 
dimming of a star that happens when a planet 
passes in front of it.
Source: indianexpress.com
Methods of Detection
– NASA’s Kepler Space telescope uses tracking the 
dimming of a star to spot thousands of planets.
– Other methods to track exoplanets include 
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.
Source: www.iasgyan.in
Why do scientists study 
exoplanets?
– The search for exoplanets is driven by the 
possibility that life may exist beyond Earth and 
even if there is no evidence for this, scientists 
believe that their hunt for an answer will reveal 
details about where humans came from and 
where we’re headed.
Source: www.iasgyan.in
What is the Ariel Space 
Mission?
– Ariel (Atmospheric Remote-sensing Infrared 
Exoplanet Large-survey), which scientists are 
planning to launch in 2029, will perform a large-
scale survey of over a thousand exoplanets over 
a period of four years.
– These thousand exoplanets will range from gas 
giants to rocky planets, which will help them to 
compile a list of their compositions and 
properties thereby providing insights about how 
planetary systems form and evolve.
Source: : indianexpress.com
Insights about how planetary 
systems
– These thousand exoplanets will range from gas 
giants to rocky planets, which will help them to 
compile a list of their compositions and 
properties thereby providing insights about how 
planetary systems form and evolve.
Source: www.iasgyan.in
Cosmic Vision Plan
– Ariel is the first mission of its kind dedicated to 
measuring the chemical composition and thermal 
structures of hundreds of exoplanets.
– Ariel will help to answer one of the key questions 
of ESA’s Cosmic Vision Plan, that is the 
conditions for planet formation and the 
emergence of life.
Source: Wikipedia
Large-scale survey 
– 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.
– Therefore, a large-scale survey that Ariel will 
perform is required to know more about 
exoplanets and exoplanetary systems.
Source: indianexpress.com