When he earned his doctorate in the United States, 27-year-old cosmologist Pedro Bernardinelli had not expected to find a comet. “That was not the idea. What happened was actually luck,” he says.
In April of this year, he found a massive star in a table full of data on scattered objects in the universe. But not only that: it was the largest comet known to mankind, about 2.5 times larger than the previous record holder.
A few days later, the then-comet C/2014UN271 changed its name to Bernardinelli-Bernstein, a tribute to the Brazilian scientist and his doctoral advisor, Gary Bernstein. “There was a name change process, but it lasted a few days. They told me to keep it a secret. It was a fun experience,” he says.
The new star was first detected in 2014, but little was known about it. Until this year, he was just a speck of light in thousands of images of the sky taken by cosmological observing telescopes. So it took on a temporary nickname, a number. Now, from Brazilian analysis, we know that it is about 4.5 billion years old and has a diameter of 150 km (the distance between Rio de Janeiro and Cabo Frio or So Paulo and Bertioga), the largest ever recorded. .
That too is coming towards the earth, but there is nothing to worry about. Figures suggest that the comet will reach its closest point to the Sun in January 2031, and will still be at a distance of 11 AU (about 1.5 billion kilometers from Saturn’s orbit).
“A joke I usually tell: to say that this object is heading towards the Earth is not wrong, because it really is. But it is the same thing as saying that, every time I get my salary, So my fate comes closer to that of Silvio. Santos. Technically it’s correct, but that doesn’t mean it’s going to get there,” jokes the cosmologist.
Brazil is part of the Dark Energy Survey (DES), an initiative with university students from eight countries, including Brazil. Collaboratively, the group aims to “mapping hundreds of millions of galaxies, detecting supernovae and patterns of cosmic structure that may reveal the nature of dark energy accelerating the expansion of the universe,” the initiative said. According to the website.
According to Des, the comet discovered by Brazil is “about a thousand times more massive than a typical comet, making it the largest comet discovered in modern times”.
Bernardinelli’s doctoral and research project had another focus: measuring the size of galaxies and the effect of dark matter on the universe.
But in analyzing data collected over the past six years, he and other colleagues have begun to find some “trans-Neptunian objects” stars that lie beyond the orbit of Neptune, the eighth planet in the Solar System.
“The great grace of these objects is that they are a kind of debris from the formation of the Solar System, they are debris that was removed. It is very worthwhile to study them because, with them, it is possible to reconstruct the history of the Solar System.” “, it says.
This year, Bernardinelli came across a comet slightly larger and slightly closer to Neptune, while analyzing a table with thousands of numbers that represent stars found in images taken by telescopes.
“It was pure luck, a fluke. He was right on the limit of what was possible to recover with the data. It was very clear it was something different,” he says.
The comet soon attracted the attention of the cosmological community because it is a typical star coming from nuvem d’orte, the farthest region of the Solar System (after Uranus and Neptune) and believed to be occupied by billions of objects orbiting the Sun.
The orbits of these stars are considered “eccentric”: they can get very close to the Sun and then become extremely distant. Most long-cycle comets from the Oort Cloud take thousands and even millions of years to complete this loop around the star.
Last year, a comet named C/2002 F3 (NeoWise) coming from the Oort cloud could be seen from Earth during summer in the Northern Hemisphere. This was a unique opportunity, as it would pass by the planet again in just 6,800 years.
Bernardinelli-Bernstein, with a “flattened” orbit, is an even longer path. “We know that it passed through the Solar System about 3.5 million years ago and that such objects were kicked into the Oort cloud 4.5 billion years ago. So we estimate it to be that age,” he says. Scientist.
The comet will have perihelion (when it gets closer to the Sun) on January 21, 2031. “That’s when it gets brighter for anyone watching from Earth,” says Pedro Bernardinelli.
According to cosmologists, this ten-year period for perihelion is a positive point of discovery. “We’ve taken this object very far from the Sun, and that’s not always the case. We still don’t understand what comets do when they’re too far from the Sun. We have ten years to monitor it, This is an incredible opportunity”, it says.
From 2023, an observatory called the LSST (Large Synoptic Survey Telescope) in Chile, which aims to find objects in the universe, will begin taking pictures of the entire sky every three days. For the Brazilian scientist, this initiative will help to better understand the comet bearing his name. “The best way to describe it is that we’ll have a picture of him every three days, we’ll have a movie of him moving around the universe”, he explains.
‘Very boring’ work
Pedro Bernardinelli was born in Itaquera and grew up in Villa Matilde, on the outskirts of So Paulo’s east side. “When the entrance exam came, I loved physics and computers, so I chose physics because it merged the two”, he says.
He entered USP and graduated in 2015. During his graduation, when he began to study the universe, a professor convinced him to give up his master’s degree and try for a doctoral scholarship at a university in the United States. He obtained it at the University of Pennsylvania, where he joined the Dark Energy Survey.
The scientist says that the job of a cosmologist himself can be quite tedious. Therefore, the image of a normal person searching for a comet that will destroy Earth through a telescope in the window of his house is not true (as in the disaster movie “Deep Impact”).
“That’s not how it works. In fact, you spend days and days looking at tables with thousands of numbers and trying to find something out there. The job is basically processing data in a supercomputer” , they say.
The same happened with Comet Bernardinelli-Bernstein. “After the table, the verification process was essentially spending hours and hours looking at black-and-white images with a very faint ball in the middle to see what this object was,” he explains.
“It’s a very boring thing. I had to stop every half hour, open the window to rest my eyes, I was already seeing everything in black and white”, he says.
In recent months, Bernardinelli has earned a postdoctoral degree at the University of Washington in Seattle. Now, he intends to better study the comet of his namesake. There are many things to discover, he says.
“We still don’t understand what makes comets move away from the Sun. We are interested in knowing what processes occur on the surface of these objects, such as the melting of ice when the Sun approaches”, he explains. .
Cosmologists and other scientists also want to know how many of these stars exist. “This is the first comet of this size ever observed. But is it unique or are there others? What is the population of these objects in the Solar System?”, he asks.