behind the Flight over Ganymede by the Juno probe in June 2021, we have all, starting with a server, been amazed by the quality of the images obtained by the modest JunoCam camera. However, the NASA probe intended to study the interior of Jupiter has made the closest flyby of a Jovian satellite that it will make in the rest of the mission. On September 29, 2022 at 09:36 UTC, Juno passed just 358 kilometers from the surface of Europe taking advantage of the passage through Perijovian number 45 (PJ45). This is the closest encounter with this moon of Jupiter since the Galileo probe traveled 351 kilometers on January 3, 2000. Of course, Galileo obtained higher resolution images thanks to its more powerful cameras since its speed does not was not that high. And it is that Juno exceeded Europa at nothing more and nothing less than 23.6 km/s.
Even so, the images are certainly stunning. As luck would have it, Juno also photographed in detail an area of the moon that had been seen in low resolution by Galileo, the so-called Annwn Regio (the name comes from Annwn, the world after death in the Welsh mythology). Although the presence of the ocean under the crust makes the surface of Europa very young, it does not change that much in such a short time, but you can join the thousands of professional and amateur experts who compare these images with those taken by Galileo in search of some change in these two decades. Da escalofríos pensar that Juno estuvo a point de ser lanzada sin la cámara JunoCam, que solo fue añadida en el último momento para no contravener la nueva norma de que toda sonda de la NASA debía llevar algún type de cámara, aunque fuese como ejercicio de “ public relations”. Because let’s not forget that JunoCam, despite the spectacular nature of its images, is not a scientific instrument of the mission and it is the amateur community which is responsible for processing and publishing the images.
In the Juno images, we can see the lines that cover the European surface, divided into line Yes pits, and which have been produced by the tensions and compressions of the icy crust. In fact, although this is Juno’s first close flyby of Europa, the spacecraft had already passed about 50,000 and 90,000 kilometers from the satellite about a year ago in two distant passes. Unfortunately, it will be the last, as Juno continues to change the latitude of its perikhovium orbiting Jupiter in order to scan the planet’s higher latitudes. It will now be necessary to wait until the end of 2023 and 2024 for Juno to approach about 1,500 kilometers from Io, the world with the greatest volcanic activity in the solar system.
Europa is a fascinating world due to the more than probable existence of an underground ocean under the outer crust of ice and, at present, it is one of the places with the greatest astrobiological potential outside of Earth. Over the next decade, Europa will be studied by NASA’s Europa Clipper mission and, to a lesser extent, by ESA’s JUICE probe and China’s Tianwen 4 probe. Unlike other ocean worlds in the solar system , the ocean of Europa is thought to be in contact with the hot, rocky interior of the moon, which increases the chances that life has appeared, and, at the same time, is also in direct contact with the surface, which allows its study from the outside thanks to the analysis of the composition of the surface ice. Unfortunately, Juno lacks spectrometers and other scientific instruments to study the composition of Europa’s ice in detail, so we will have to wait for Europa Clipper. In recent years, the biggest mystery in Europe is the possible existence of geysers.
If so, its ocean could be studied from the outside in a much simpler and more accurate way. Although there is evidence that water vapor and other substances are expelled from the surface, it has not been possible to confirm that these are real geysers, as on Enceladus. In this sense, Juno’s plasma sensors can give limited information about the mystery of the geysers, while the magnetometer can provide new information about the interior of this moon. Similarly, the MWR (Microwave Radiometer) instrument will be able to give us a new view of the temperature of the icy crust. After this flyby, Juno will continue to orbit Jupiter every 43 to 38 days to study Jupiter’s interior, which is its primary mission. The last orbit of the current extended Juno mission will take place in September 2025. In any case, these images are a small taste of what awaits us with Europa Clipper. The wait will be very long!
Thanks @NASAJunothere is a new picture of #Europe it made me super jazzed about science. Just what I needed today! Here are some side-by-sides I put together of Galileo/Voyager tiles (left) and new Juno data (right). pic.twitter.com/OCECUvycpU
— Alyssa Rhoden (@aRhoDynamics) September 30, 2022