Ersilia Vaudo: Mirabilis and our idea of ​​the universe

“NoWe are children of the stars” sang Alan Sorrenti in 1977. Reading Mirabilis. Five intuitions (more to come) that have revolutionized our idea of ​​the universe of astrophysicist Ersilia Vaudo, it makes you smile because the song, unintentionally, evoked a scientific truth. «Apart from the first lighter elements, born in the first moments after the Big Bang, most of the others that make up our world were born in the heart of the stars or in one of the explosions that mark their end» says the scientist, who in this book takes the reader by the hand and tells him about our extraordinary adventure towards the knowledge of the cosmos.

Ersilia Vaudo, we with our eyes to the sky

Human beings have been observing the sky since ancient times. For centuries, those objects at sidereal distances – including our satellite, the Sun and the planets of the Solar System – have seemed unknowable to us, worthy of conjecture related to myth or religion. Then, scientists have entered the scene by discovering pieces of truth of this immense puzzle, thanks to their brilliant insights. The gravity that causes an apple to fall is also responsible for the orbit of the planets, Newton’s word. ANDinstein reflects on the speed of light and the relationship with space and time to develop his theory of special relativityfollowed by general relativity.

The universe ceases to be immutable, it even has a beginning – the Big Bang – and Hubble reveals the existence of other galaxies besides ours. Then comes Dirac, with an equation: every known particle has a kind of opposite twin, the antimatter. The author guides us along the way making this complex subject within anyone’s reach. A graduate in Astrophysics from the Sapienza University of Rome, Ersilia Vaudo has been working for the European Space Agency (ESA)currently holding the role of Chief Diversity Officer in Paris. She is also president and co-founder of the association “Traveling Heaven“ which promotes the scientific literacy of children in areas at risk of dropping out of school. “We go around in a minibus equipped with telescopes and laboratories so that the little ones can get their hands dirty with science and observe the sky,” she underlines.

How was your love for this subject born?
I had the privilege of growing up in a family where science was valued. My mother wrote the chemical formula of the contents on the jars in the kitchen so that my brothers and I could get used to other languages. I wanted to study Philosophy, but I chose Physics because it gave me a sense of freedom, of empowerment. It’s the only subject that takes you out of the comfort zone of your experience by asking you to change your way of thinking.

What is the genesis of this book?
It all starts with a 2015 Ted Talk on the resilience of the universe, in which I told how important it was to keep an open mind to the arrival of new ideas. The scientist must be curious, sometimes stubborn. I’m very passionate about talking about this reality that is bigger than us, which ignores us and contains us, which is unknown to us but is not antagonistic and capable of activating great emotions. The book was born from the idea of ​​sharing in written form the wonderful that is part of our daily lives.

Earthrise, 1968, and Pale Blue Dot, 1990 are two photographs that have gone down in history. Why?
They represent those first times when we encounter something unexpected. In 1968, as they circled the Moon, Apollo 8 astronaut Bill Anders snapped a picture of the Earth rising on the horizon, suspended in eternal night, shrouded in a thin blue halo. It made possible the thrill of watching ourselves from afar. Pale Blue Dot is the last photo taken by Voyager 1 as it was exiting the solar system in 1990: six billion kilometers away, the Earth is a fragile and insignificant dot, “a speck of dust suspended in a ray of the sun”. as Carl Sagan said. Our only home. That shot makes me think of the greeting of a child who looks at his mother before leaving on the first day of school.

A sunset by the sea: we would like time to stop in that instant, in reality we are living in the past. Why?
Light propagates at a precise and insurmountable speed: 300,000 km per second. To travel the distance between the Sun and the shore on Earth takes about eight minutes. Thus, the scene before our eyes already belongs to the past. The further away a star is, the more the image we observe dates back to a remote time. The light of Rigel, in the constellation of Orion, that we see today started when Dante was being born in our world.

Time passes more slowly by the sea than on a mountain top. Why?
It is one of Einstein’s great insights. Gravity also affects the passage of time. The closer you are to Earth, the slower time passes. If you go further away, up a mountain or in an airplane, time advances, even if imperceptibly, faster.

Does gold also come from the stars?
I would say rather from their clash. In 2017, the collision between two neutron stars was observed for the first time. Many heavy elements were formed including an amount of gold equal to tens times the mass of the Earth.

Do the stars die?
Of course and in different ways, depending on their weight. When it runs out of fuel, the Sun will expand and collapse into a white dwarf. Heavier stars can become supernovae and black holes. In 4.5 billion years, the Sun will also go out.

In reality, the Andromeda galaxy poses a more imminent risk.
Thankfully, not too much. Andromeda is “running” towards the Milky Way. In four billion years, there will be a great clash.

With all these discoveries, is there still something left for you astrophysicists to study?
The mysteries are still many. For example, we know that there are about 100 billion observable galaxies. But with our telescopes we can see only that which emits light, which makes up no more than 5 percent of the universe’s contents. There remains a 95 percent that we know exists only from gravitation, of which 20 percent is probably made up of dark matter while the rest could be some kind of dark energy, which fills the universe and is responsible for its acceleration. The ESA Euclid mission which will start next July will have the task of investigating.

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