The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
Find out more about space activities in our 22 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
Exploring our Solar System and unlocking the secrets of the Universe
Go to topicProtecting life and infrastructure on Earth and in orbit
Go to topicUsing space to benefit citizens and meet future challenges on Earth
Go to topicMaking space accessible and developing the technologies for the future
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An artist's impression of the Jupiter-size extrasolar planet, HD 189733b, being eclipsed by its parent star.
Astronomers using the Hubble Space Telescope have measured carbon dioxide and carbon monoxide in the planet's atmosphere. The planet is a ‘hot Jupiter’, so close to its parent star that it completes an orbit in only 2.2 days.
This type of observation is best carried out when the planet's orbit takes it behind the star (as seen from Earth), allowing for an opportunity to subtract the light of the star alone (when the planet is hidden behind it) from that of the star and planet together before an eclipse. This allows astronomers to isolate the infrared emission of the planet and carry out spectroscopic observations that chemically analyse the day-side atmosphere.
The planet is too hot for life as we know it. But under the right conditions, on a more Earth-like world, carbon dioxide can indicate the presence of extraterrestrial life. This observation demonstrates that chemical biotracers can be detected by space telescope observations.