ESA’s Jupiter Icy Moons Explorer (Juice) made an extraordinary discovery during its flyby of Earth on August 20, 2024—confirming the presence of life-sustaining elements in our planet’s atmosphere. The flyby was not only significant for the data collected but also served as a crucial test for Juice’s science instruments, preparing them for their primary mission: exploring Jupiter and its icy moons.
Using the Moons and Jupiter Imaging Spectrometer (MAJIS) and the Submillimetre Wave Instrument (SWI), Juice gathered data confirming Earth’s habitability. MAJIS captured detailed images of the Pacific Ocean, providing an infrared temperature map of Earth’s surface. SWI focused on detecting signals from hundreds of molecules, especially the CHNOPS elements (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur), fundamental to all known life forms.
Through MAJIS, essential components like oxygen, ozone, carbon dioxide, and water were identified in Earth’s atmosphere. In particular, the MAJIS team is eager to analyze the concentration of oxygen further, hoping to better understand whether these levels are sufficient to support biological activity.
ESA Juice project scientist Olivier Witasse commented on the findings: “We are obviously not surprised by these results… it would have been extremely concerning to find out that Earth was not habitable! But they indicate that MAJIS and SWI will work very successfully at Jupiter, where they will help us investigate whether the icy moons could be potential habitats for past or present life.”
Once Juice reaches Jupiter, SWI will study the chemical composition of the planet and its icy moons to better understand their climates, origins, and histories. The data could unveil not only the moons’ habitability but also any signs of biological activity. Additionally, MAJIS will investigate Jupiter’s clouds and atmospheric ingredients, along with the ices and minerals on the surfaces of its moons.
The SWI instrument is a collaboration led by the Max Planck Institute for Solar System Research in Germany, with significant contributions from national agencies, including DLR Germany. MAJIS, on the other hand, was developed by a large European consortium, with major contributions from France and Italy.
This flyby has not only confirmed Earth’s life-supporting attributes but also set a promising precedent for the Juice mission’s objectives at Jupiter, potentially opening new doors to understanding extraterrestrial environments.