Portuguese 
English 
Spanish 
4 min of reading 
0 comments 
Scientists Found New Evidence That Supermassive Black Holes May Be Responsible For The Generation Of Gravitational Waves
Ten years ago, a discovery changed physics. Using detectors in Washington and Louisiana, scientists identified, for the first time, gravitational waves – small ripples in spacetime.
The confirmation of Albert Einstein’s theory earned the Nobel Prize in Physics in 2017 and opened a new window for the study of the cosmos.
Now, a new detection promotes even further progress in this field. Scientists identified a background hum generated by a different type of gravitational wave, possibly produced by supermassive black holes.
-
A country surrounded by scarcity transforms treated sewage into an “agricultural weapon” while the river that supplied generations becomes a regional dispute: Israel recycles almost 90% of its wastewater for irrigation and exposes the water abyss of its neighbors who still depend on what’s left in the Jordan River.
-
Climate change and pollution elevate heart risks: analysis with over 8 million people links extreme heat to 7.5% more complications and 9.5% more deaths, while pollutants already appear in 13% of cardiovascular deaths.
-
An online tool recreates the position of your house on Earth over up to 320 million years and shows how tectonic plates, lost continents, and geological collisions changed the planet’s map up to the present day.
-
China proposes to transform the rarefied atmosphere of Mars into electricity, heat, and fuel with CO₂, nuclear microreactors, and a Sabatier reactor, in a study that could reduce dependence on cargo sent from Earth and pave the way for more autonomous human missions.
The discovery raises intriguing questions and may lead to a deeper understanding of the structure of the universe.
What Are Gravitational Waves?
Gravitational waves arise whenever a massive object accelerates. In the case of the first detection in 2015, they were produced by two black holes within our galaxy that collided after orbiting each other.
The concern was captured by LIGO (Laser Interferometer Gravitational-Wave Observatory), which has arms of 4 km and detected tiny variations smaller than the width of an atom.
This time, the signal detected is different. Instead of high-frequency gravitational waves that last only a few seconds, astronomers are detecting low-frequency waves, with wavelengths that can stretch across light-years.
They appear to come from all directions in the sky and are produced by supermassive black holes orbiting each other for millions of years before merging.
How Was The New Detection Made?
To identify this cosmic hum, scientists developed radio telescopes known as “pulsar timing arrays.”
Pulsars are extremely dense and rotating neutron stars that emit very precise radio signals.
As a low-frequency gravitational wave passes, these signals undergo slight changes. Researchers analyze these changes to infer the presence of the gravitational waves.
The latest data was obtained by the MeerKAT radio telescope in South Africa. With just four and a half years of observation, MeerKAT achieved results similar to previous studies that required over 15 years of data collection.
The discovery was published in the journal Monthly Notices of the Royal Astronomical Society.
Matthew Miles, an astrophysicist at Swinburne University of Technology in Australia, explains that low-frequency gravitational waves stretch or contract the universe by about 20 meters.
This means that pulsars, located thousands of light-years away, function as a natural detector, much larger than any equipment built by humanity.
Mysteries Still Unanswered
The new data brings some enigmas. One of them is that the background hum seems more intense than expected. This could mean that there are more supermassive black holes in the universe than previously thought, or that these objects are even larger than earlier models.
Another mystery is the gradual increase in the intensity of the hum. One hypothesis is that some source of gravitational waves is relatively close to our solar system, affecting the data.
Furthermore, the intensity of the gravitational waves seems greater in the sky of the Southern Hemisphere than in the Northern Hemisphere, something scientists call a “hot spot.”
One possibility is that a pair of supermassive black holes in question is closer than others, influencing the data. However, it is still uncertain whether this asymmetry is real or just a statistical error.
The Future Of Gravitational-Wave Astronomy
The expectation is that new telescopes and technologies will help clarify these questions. The Square Kilometer Array (SKA), a large array of radio telescopes in South Africa and Australia, is set to start operations in 2027 and promises to significantly improve the accuracy of directions.
Scientists believe that in the next decade, it will be possible to directly detect pairs of individual supermassive black holes instead of just a diffuse hum in the background of the universe. This will allow for better study of the origin and evolution of these cosmic structures.
Astrophysicist Floor Broekgaarden from the University of California compares this discovery to listening to different types of sounds in a busy square.
If the first gravitational waves detected in 2015 were like the higher vocals of a choir, now scientists are starting to hear the low instruments.
The existence of supermassive black holes at the center of galaxies was already known. The one in the Milky Way, called Sagittarius A*, was detected in the 1970s by its radio emissions and photographed in 2022 by the Event Horizon Telescope.
Now, astronomers want to understand how these giants form and interact over time.
With information from Smithsonianmag.
Be the first to react!