A spacecraft en route to the frozen moons of Jupiter has taken a very close look at Earth, and found that our homeworld is, in fact, habitable.
During an August 20 flyby, the European Space Agency's Juice probe turned its MAJIS imaging spectrometer and SWI submillimeter spectrometer to Earth's atmosphere, looking for molecules and elements that, together, indicate that life could not only emerge and survive on a world, but may even be there right now.
Of course, we know that life is crawling around on Earth. But that, in fact, is precisely why astronomers looked.
Juice is going to the moons of Jupiter that are most likely to harbor life as we know it – so scientists wanted to make sure that its instruments are able to make the relevant detections once they get there.
"We are obviously not surprised by these results… it would have been extremely concerning to find out that Earth was not habitable!" says planetary scientist Olivier Witasse of ESA.
"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."
The two instruments measured different ingredients in Earth's atmosphere. MAJIS measured the composition, including oxygen, water, ozone, and carbon dioxide. It also compiled infrared heat maps of Earth's surface.
SWI, on the other hand, took a tally of a suite of elements known as CHNOPS elements. That acronym stands for carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur – the six most common elemental ingredients in living organisms.
Everything appeared to be all present and correct, which is good news for us on a few levels, when you think about it. The Juice team will be digging further into the data like ferocious little data ferrets, analyzing it and making sure that the data collected is consistent with other data and observed reality.
Meanwhile, Juice, which launched in April of last year, is continuing to take the scenic route to Jupiter, with several more flybys of Earth and Venus scheduled before its arrival in Jovian orbit, currently slated for July 2031.
Once there, it will examine the giant planet and moons Ganymede, Callisto, and Europa – each of which harbors a hidden ocean whose floor may be teeming with marine life.
If there's anything there, Juice represents our best hope to date of detecting it. Safe travels, little spacecraft.