Galileo Galilei only needed a small telescope to see Jupiter’s moons four centuries ago. When he looked again the next day, they had changed sides. He realized that these moons orbit Jupiter. This completely changed the idea of our solar system: it proved that not everything revolves around the Earth. Thus, the Galilean moons are the cradle of modern astronomy,” says Nick Oberg (33), who has studied the formation of Jupiter’s moons.
Oberg lives in Almere with his girlfriend. “The last two years of my PhD research were in Delft, but my girlfriend is still working in Groningen. Elmere was within reach for both of us,” he says. Their living room is lined with garlands of planets. Hans Kluck’s face is large on the cup of tea served. This mug comes from a thrift store, where they make choosing “shy” mugs a game. The cookies come from Belgium, where Oberg originated.
“I fantasized about spaceships like any little kid would, and for a long time I thought studying astronomy was just a childhood dream of mine. It occurred to me that I could chase that dream. But astronomy is less romantic to some than it seems. It’s mainly a lot of heavy math and programming.” After the lecture The first, about dimensional analysis, I was terrified.”
However, he immediately wanted to become a scientist. At the University of Groningen and TU Delft, he delved into the formation of the moons of Jupiter, the fifth planet in our solar system and the largest. When our solar system formed, the sun was at the center of a colony of stars. Some of these massive stars exploded immediately after their formation, and the waves from these exploding stars affected the formation of planets in our solar system. I wondered what that meant for the formation of moons.”
Space for hundreds of large moons
The planets’ gravity pulls matter in, but the radiation from those giant stars blasts it away. “When this attraction and repulsion balance out, a small disk of dust and gas is created. That clumps together into moons.”
Jupiter has room for hundreds of large moons due to its strong gravity, but it only has four. Oberg: “Maybe because this disk was so young. Unfortunately, we can’t verify that easily, because it all happened over four billion years ago. So we simulated the radiation of all those stars, based on observations of other star clusters forming.”
Oberg also identified the material the moons are likely to be made of. He had to go back to chemistry, which he hadn’t seen since high school. Half of the moons are ice. But what exactly was the type of ice cream that was a big question mark. There are many more types of ice than water. For example CO2Ice cream for parties. Or ammonia ice, which melts at a lower temperature. This may indicate that there is a larger ocean beneath the surface, which is interesting to search for life.”
“Liquid water in itself is not an indication of life, but it would be a good sign. Unfortunately, the moons of Jupiter have no atmosphere. It could tell us a lot about the interior if they did.”
In April, the European Space Agency launched the Juice mission: the space agency launched a probe destined for the moons of Jupiter. “It would be a big surprise if there wasn’t an ocean hidden under the ice on Europa, one of Jupiter’s moons. The question is rather what that ocean looks like. But we’ll have to wait patiently for another eight years until the probe arrives.”
The telescope is forty meters wide
The world’s largest optical telescope, with all mirrors about 40 meters wide, is currently being built in Chile’s Atacama Desert: the Extremely Large Telescope. “Astronomers aren’t very creative when it comes to naming things,” Oberg says, laughing about the rather simple name. “With ELT, we would like to capture the formation of moons in the solar system HD100546, post Attractive The name, to see if those moons are actually forming from dust and gas disks. “
Oberg says that actually witnessing space phenomena is usually only the last step in the investigation. “You have to be able to fully justify your research to book time with such an expensive telescope, you have to prove a lot up front. Logical, but that reduces the chance that we’ll discover something by chance.
Galileo’s discovery was a stroke of luck: Jupiter’s moons appeared in his field of vision. He himself did not go in search of satellites of other planets, because they simply had no idea about their existence. I think we should take bigger risks in space research, to find things outside of our model as Galileo did. We don’t know what we’re looking for, so we don’t look for it.”
