Earth has sprung a leak. Every day, 90 metric tons of matter leaks from Earth’s upper atmosphere into space. This sounds scary, but in total the atmosphere weighs about five quadrillion metric tons, so we have a lot of atmosphere to work with. Still, scientists are paying attention to the leak, because it could help us understand what makes a planet habitable.
Back in 2000, the European Space Agency (ESA) launched their Cluster mission: four spacecraft that are currently gathering information on Earth’s atmosphere and magnetic field. Cluster has scrutinized the magnetic interactions of the Earth and the Sun.
The Sun shoots us solar wind – or “thin, hot, ionized gas that carries particles and magnetic fields,” according to ESA, but some of the particles can get in near the poles and atmospheric materials can escape. Scientists used to think the magnetic environment of the Earth contained only those particles from the sun, but realized as recently as the 1990’s that Earth’s atmosphere is leaking.
Understanding this phenomenon, however, could help us understand more about what makes a planet habitable – or not. For example, ancient Mars was maybe habitable, but its atmosphere is now severely depleted. Theoretically, we could apply knowledge of our own atmosphere to “any astrophysical object with both an atmosphere and a magnetic field.” ESA scientist Arnaud Masson, the Cluster mission’s Deputy Project Scientist, said, “Understanding how atmospheric matter escapes is crucial to understanding how life can develop on a planet.”
Another ESA Cluster mission scientist, Philippe Escoubet said, “Understanding more about our own atmosphere will help us when it comes to other planets throughout the Universe. We need to know more. Why does Earth have an atmosphere that can support life, while other planets do not? Overall, long-term space missions like Cluster are helping us to understand a whole lot more about our planet, its atmosphere, and atmospheric loss in general – which in turn will help us understand the Solar System in which we live.”