A life in the shadow of giant planets


Audrey Vorbuger and her three children: a shared passion that might lead to careers. ltd

What if we found life in an ocean hidden beneath the ice surrounding one of the moons of Jupiter, Saturn, Uranus or Neptune? It’s a crazy gamble by the European Space Agency (ESA) that a young Bernese astrophysicist is willing to take.

This content was published on January 11, 2023 – 09:33

At 38, Audrey Vorbuger hit the jackpot. Juice is now a co-investigator on the missionExternal linkThe astrophysicist from the University of Bern, who will leave this spring to study three moons of the Jupiter system, was appointed last year to the ESA Expert Committee Moons of the Giant Planets.External link. His task: to outline a large European mission to replace Juice, a satellite of one of the four gas giants of the solar system. The team will need to determine the most appropriate mission profile to answer the question: is there life out there?

ESA Roadmap 2035-2050

A space mission is planned years, even decades, in advance. Back in March 2019, ESA launched a wide-ranging consultation with scientists across the continent to develop Voyage 2050.External linkIt is supposed to last from 2035 to the middle of the century.

Three priorities have been identified for future missions:

– Search for biosignatures on moons of giant planets. This is the research area of ​​Audrey Vorburger and her colleagues

– Characterization of our galaxy’s temperate exoplanets to see if they offer favorable conditions for life. The goal here is to find successors to the present and future space telescopes Cheops, Plato and Ariel.

– Exploring the primordial universe. The goal here is to seek answers to fundamental physics questions about the formation of the first cosmic structures and the first black holes.

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swissinfo.ch: It’s hard to imagine that one of our best chances for finding life in the Solar System other than Mars is on icy moons so far away…

Audrey Vorburger: Until about 1995, it was not believed that life could exist in the outer solar system. First we focused on the Moon, where we found no life, then we looked at Mars, and we are still looking there for possible traces of past life.

Then something interesting happened with America’s Galileo probe. All objects in the outer solar system were thought to be geologically dead, lacking the energy to sustain life. But we found that under the ice there are huge oceans of water during these months. Jupiter’s moon Europa, which is much smaller than Earth, contains more water than all of Earth’s oceans. And there may be life in these protected oceans.

But they are miles under the ice, it must be dark there. Isn’t light essential to life?

For the most widespread life on Earth, yes. But there is life in our oceans without even light. In fact, light is only one form of energy, and it is the energy that life needs. There are other forms of it, nuclear radioactivity and tidal forces from motions around the planets, which generate heat. And all this is energy.

>> This ESA video animation shows the complex trajectory of the Juice probe, which will launch to Jupiter’s moons this year.

External content

This second European mission to the ice moons is due to leave in the 2040s. So counting the journey and the work of analyzing the data, you’ll be close to retirement by the time the results are announced. Isn’t that a little frustrating?

On the contrary. I am very happy to be there at the very beginning of the conceptualization of the mission. And I’m so glad to see how it’s grounded in science and science.

ESA does not tell us “this is what is technologically possible, tell us what mission we can do with this technology”. On the contrary, the Agency asked scientists “what does humanity want to know?” What should we do and how do we make it possible?” So we brainstorm, come up with crazy ideas, and say to ESA, “this is what we want, is it possible?”

Then we have this game where the scientists are pushing for more and ESA is responding to us in terms of technology, budget, power and weight constraints, and we’ve put it all together in one mission.

And where is the development of this future mission today?

In the first half of 2022, we discussed the targets, as they will determine the type of mission. Jupiter’s Ganymede and Callisto have geologically quiet surfaces, but so does Saturn’s moon Enceladus, which has giant geysers spewing matter into space. It can also be in Europe.


This artist’s impression shows what the geysers of Saturn’s moon Enceladus might look like. ESA

To search for possible habitats and signs of life, we must first determine which months are the most promising. We don’t have to limit ourselves to a single moon, in theory multiple missions to visit the moons of Jupiter and Saturn would be possible. Next, we need to determine the most promising mission profile. This will vary from month to month depending on where the potential habitats are and how they are sampled – soil? to the geyser? the ocean?

But here, too, we quickly reach the technological limits of mass and power, because being so far from the Sun, there is very little light left to power the solar panels. Having a nuclear-type power source like the Americans plan to use would be the solution, but the ESA made a political decision not to send radioactive material into space. So we will deal with batteries and panels.

So far we have talked about Jupiter and Saturn. Could there also be possible targets around Uranus or Neptune?

Of course yes. There is Triton, a stellite of Neptune, which also has geysers. But we must remember that Jupiter is eight years away, Saturn twice, Uranus four and Neptune six. So, if we have a good chance around Jupiter or Saturn, there is no point in planning a mission to Uranus or Neptune, which will cause even more technological problems.

At the same time, NASA plans to go to Uranus. So there is potential for collaboration.

>> Audrey Vorburger explains her fascination with Uranus and what would happen if she tried to land on the “surface” of these giant planets, which actually have no surface.

The goal, we said, is to find alien life — even if it’s just bacteria. What is your personal belief on this? Are we alone in the universe?

I’m sure there is life elsewhere. I don’t know if life on Earth happens by chance, or if conditions are similar elsewhere, we’ll have the same chance of seeing life. Because we still don’t understand how life originated. But I think it’s worth seeing in our solar system.

And for the universe as a whole, I think it’s even harder for us to be so special. There must be life elsewhere, there are many possibilities.

What would you say to those who believe that money spent on the space sector is a waste when there is so much to do on Earth?

People have always been curious, they want to know why we are here, where we came from and why things are the way they are.

At the same time, one cannot forget how much technology came out of these space programs. It’s not immediately obvious, but think of survival blankets, water purification systems, adjustable smoke detectors, memory foam, computer mice, wireless headsets, telecommunications, earth observation foils that help us with weather forecasts or tsunami warnings. a few examples.

I also think it’s good to look at what can happen to the Earth if we don’t take enough care of it. For example, look at Mars and Venus, they are very similar planets to ours, but both are uninhabitable. On Mars, there is no air to breathe, and on Venus, with the terrible greenhouse effect, a person is immediately crushed by pressure, burned by temperature and killed by toxic gases.

You are a woman in a rather masculine environment. How does this happen?

It’s a competitive field like many others. Look at the statistics: how many people start studying physics, how many go to doctorates, and then to professorships. You really have to prove yourself.

But I never felt any difference between my male colleagues, my office and the neighborhood. There are about ten of us in this team of ESA experts, half women and half men. We are getting used to seeing more and more women and they are respected like men.

So, personally, I have never experienced discrimination. The fact is that you have fewer women, especially outside of Ph.D., and that’s something we need to discuss. But we are moving forward: I have three children, I was able to take care of them after they were born, and I work only 60%.

Is one of your three children a future space scientist?

i would like It’s an interesting job, they are very passionate about everything related to space. My 4 year old daughter already knows all the planets in the solar system. On the other hand, it’s a lot of work, I travel a lot, I’m often away from them. But when I’m there, I work a lot from home and they see how much I like it. This is something I want to pass on to them, that work can be experienced not as a chore, but as an activity that you really enjoy.

Reviewed and approved by Sabrina Weiss

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