Pontifícia Universidade Católica do Rio Grande do Sul







Recent findings on the black holes

Astrophysicist Janna Levin discusses major achievements of Physics at Frontiers of Thought

06/09/2019 - 10h11
Image: Luiz Munhoz

Image: Luiz Munhoz

The evolutionary findings of black holes in the universe was the central topic of discussion of US astrophysicist Janna Levin at the event Frontiers of Thought, on Aug 2, at the Commencement Hall of UFRGS. An eminent researcher, Levin holds a PhD in Theoretical Physics from the Massachusetts Institute of Technology (MIT). She has written the book The Music of the Universe. In her session, she commented on the great achievements of Physics, such as the sound of gravitational waves as two black holes merge and the images of some of these intriguing celestial bodies.

“We live on the edge, rather than at the center of the universe. There are thousands of stars and galaxies and we can only see them because they shine. On the other hand, black holes are dark phenomena, mere shadows”, she says. As she used animations in her presentation, Janna showed the audience how a star becomes a black hole. “Inside of it, it would look like it was dying. Do you know that light that you see right at the end of the tunnel? That is the image we are talking about”, she adds.

One of the greatest discoveries in Physics was the sound of gravitational waves as two black holes merge in 2016. Three billion years ago two large celestial bodies collided. This led to a massive explosion and formed a lonely object 49 times larger than the Sun. “When they move, black holes create waves and make sounds through gravitational waves. Contractions and expansions cause sounds to oscillate – from low to high – as they come closer to each other. When they collide they also make a sound”, she said as she presented the noises to the audience.

In order to make it happen, Janna though of the 40 years of dedication of her friend Rainer Weiss, a German physicist and one of the leading researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO). This observatory was where the sounds and sounds were captured. It is located in two US cities: in the states of Washington and Louisiana. LIGO employs over 800 people from various countries. This earned Weiss the 2017 Nobel Prize in Physics.

She also mentioned another major milestone for Physics this year: the first image of a black hole. It took a network of powerful radio telescopes to picture the hole. Although light cannot escape it, researchers could see it in the middle of the photon ring surrounding it. “There are as many as one billion black holes in our galaxy. That is why it is hard to believe that there is no life anywhere else”, she says.

Future discoveries

Image: Luiz Munhoz

Image: Luiz Munhoz

When she was asked about upcoming discoveries, Janna pointed out that in the last century, the great achievements of Physics allowed us to believe that the future is very promising. “We got to capture something we never thought about: the sound in the black hole”, she says.

The way she see it, 95% of the universe is dark, 25% of which consists of dark matter. “This shows that there is a lot to be discovered. The universe has extra dimensions. We can anticipate that Big Bang was not the only one”, she claims.

Opportunities for research

Astrophysicist Thaisa Storchi Bergmann talked about the context of research in Brazil and asked Janna about the importance of investments in research and the current scenario of the United States. To Levin’s mind, there are also investment problems in her country and that, in some cases, the money comes from different sources. “Research inspires people; it brings about major changes. We usually make wonderful discoveries. In our projects, we have scientists from several countries, including Brazil. The world benefits greatly from these investigations”, she concludes.