There would be no accurate GPS without Einstein. And no WiFi without Stephen Hawking’s discoveries on black holes. «Space research changes everyday life», says cosmologist Roberto Trotta whom we met at the Web Summit in Lisbon. «But above all, it will one day answer the Great Question: why do we exist?»
Roberto Trotta has become famous thanks to a book (The Edge of the Sky, Basic Books).in which he explains how the universe works using the 1000 most common words of the English language. It is so people-friendly that its main character sounds Harry Potterish (The-All- There-Is). And the publication was so powerful that the American magazine Foreign Policy included the 41-year-old Swiss theoretical cosmologist, who teaches at Imperial College London, among the 100 Global Thinkers who will change the world. Roberto Trotta
Yet while we talk to Roberto Trotta at the Web Summit in Lisbon (about dark matter, multiverse, coins that mysteriously fall all face up).every now and then we lose track. Shame on us! Unfortunately, physics lessons are, for who’s writing, not as much a memory to freshen up. but a nightmare to forget. «No, no, if you don’t understand what I’m saying it my fault, not yours», he says, kindly. Roberto Trotta
Why is it so difficult for scientists to share what they know?
«Because in order to do that, they must consider the detail irrelevant. Which is the opposite of what do when they work. In order to be understandable, it is necessary to provide a bird’s eye view and bring it back to the ground, clarifying why what seems distant and irrelevant is not».
Please enlighten me. I’m one of those people who always wondered what was the point in calculating the age difference between a twin in space and the other on earth.
«The point is to understand that time is not an absolute value. and its flow depends on the reference system with which it is measured. It is a theory – Albert Einstein’s relativity – that you uses every day without knowing it. This morning, for example, you probably used the satnav to come to our appointment. Without Einstein you would have ended up 10 km away from where we are. Because where satellites fly, time flows differently than what it does on earth. And smartphones use an algorithm based on Einstein’s theory of relativity to account for the gap. This is why they take us to their destination».
Without Einstein, no GPS?
«Exactly. Although Einstein
Give me another example.
«We could not use wi-fi if Stephen Hawking had not predicted, in 1974, that black holes evaporate over time». Roberto Trotta
What does wi-fi have to do with black holes?
«In the 1990s John O’Sullivan, an Australian engineer, developed an algorithm that eliminated radio interference. He was looking for a way to “clean up” the data from telescopes so he could detect Hawking’s predicted signal on the explotions of black holes. Without this algorithm, we could not use wi-fi. And without disturbing Hawking, I, too, in my small way, am applying astrostatistics to more ground-to-ground problems».
«With the startup Utonomy, I use methods that I invented for the analysis of powerful stellar explosions (the Supernovae) to predict the fluctuations in the demand for methane gas. For those who distribute it, adapting the supply means reducing the pressure on the pipes and consequently the leaks, which cost 200 billion a year in England alone. Not to mention the greenhouse effect. I also use statistical methods that discover anomalous events in the universe to analyze credit card data. Thus it is possible to identify suspicious transactions».
You convinced us. But why is it so important for scientists to involve an extended audience?
«Because space research is often accused of irrelevance. Especially when there are pressing and complex issues, such as Climate Change or the loss of ecosystems.which have finally become public domain. Why should we spend resources and energy on space? Why should young mathematicians waste their time with astrophysics.when they can get rich using statistics in finance? The answer to these questions must be given by scientists. And one of the possible ones is to explain, as we have done now, that this research has always proved fundamental for improving life on earth».
If this is one of the possible answers, what are the others?
«The less pragmatic but more fascinating ones. We study the universe because understanding its nature will make us figure out what is our place in it. Thanks to fundamental research one day, I am sure, we will understand why we are here».
So we will be able to explain the meaning of life?
«Basically yes. As physicists, the question we ask ourselves as a starting point is: how is it possible that the laws of the universe are such as to allow the evolution of biological entities such as ours?»
And what’s the answer?
«The one that is increasingly taking hold, since we are able to analyze a huge number of data from the universe, is probabilistic. It is also called the multiverse. It says that the universe is not unique but a collection of spheres, sub-universes that work each according to different laws. And that these are so many that, based on the calculation of probabilities, there has to be one with the exact physical laws that provide life». Roberto Trotta
The universe would be one of the thousand possible but also the only one able to make us live?
«If you say a thousand to indicate a much larger number, yes. But to clarify what we are talking about, I ask you to imagine entering a room and finding 400 coins on a table. all with the “head” up. Would you ever think that they were launched at random? Obviously not. The odds would be infinitesimal. But these are the same odds for our universe to have physical parameters like those that it possesses.
At this point my head is spinning.
«It’s very normal. Because it has been calculated that the multiverse contains 10 to the power of 500 spheres. That is, a number of spheres equal to 10 followed by 500 zeros, an unimaginable number. But that’s what we need to ensure that at least one has the right conditions for life».
Perhaps it is then simpler to think that God exists.
«Sure. It is the theological explanation. But it is not that of science, which instead gives it a probabilistic nature. The answer is still open because even the scientific explanation is not proven. For now».
How do you study something whose existence is not even sure?
«In small steps. My team and I work on dark matter and energy that represent 96% of the cosmos. Understanding what they are made of and how they work will help us clarift the fate of the universe. We know, in fact, that it started to expand from the Big Bang (30.7 billion years ago). Until not so long ago it was thought that the expansion was slowing down, with the energy released by the Big Bang that was depleted due to gravity.
But it has now been proven (by the team of Adam Riess, Nobel Prize for Physics 2011) that expansion is accelerating. The hypotheses on why this happens are different, but focus on the role of matter and dark energy. It would be the dark energy that, victorious on gravity, is leading galaxies to move away. The question then is: will the universe continue to expand? And if so, will it end up “tearing”? Or will the gravitational force take over the dark energy and the universe will gather on itself in a backward Big Bang, the so-called Big Crunch? Thanks to astrostatistics we can make more informed hypotheses about the future of the universe, on the multiverse. but also on the fundamental nature of the matter we are made of».
Mathematics has always been used in physics. What has changed today?
«The scale: we have more complex data that require more complex mathematical manipulations. The study of the universe is not done by looking into a telescope but by writing programs that manipulate, interpret.and analyze data that no human could ever understand with the naked eye. It is thanks to astrostatistics that today we are able to “visualize” the light after the Big Bang, the explosions of the most distant stars (the Supernovae) and the dissolution of galaxies. And to simulate the distribution of dark matter in the universe».
Let’s go back to the earth. Have you already convinced your children to study astrophysics?
«Emma is 8 and wants to be an astronaut. Ben is 3: he is reckless and loves stories. I’m on the right track».
Perhaps they will help you to realize your scientist’s dreams. What is the biggest?
«That of everyone like me. Finding the theory of everything. The equation that explains the nature of the cosmos. I would print it on a t-shirt right away, because no one says that science is not pop».