Scientists have made a groundbreaking discovery, observing the faint ripples caused by the motion of black holes that are gently stretching and squeezing everything in the universe. This is the first time that researchers have been able to observe low-frequency gravitational waves, which are changes in the fabric of the universe created by large objects moving and colliding in space. The research collaboration NANOGrav published their findings in The Astrophysical Journal Letters.
Albert Einstein predicted the existence of these ripples, and the detection of gravitational waves in 2015 confirmed his theory. However, previous methods could only detect waves at high frequencies. The latest research focused on finding waves at much lower frequencies, which can take years or even decades to cycle up and down. These slow ripples are likely caused by supermassive black holes billions of times the mass of our sun, which orbit each other before eventually merging.
To detect these low-frequency waves, scientists used pulsars, which emit regular bursts of radio waves as they spin in space. Gravitational waves affect the distance between Earth and these pulsars, causing tiny changes in the arrival time of the radio waves. By analyzing these changes across different pulsars, scientists confirmed the existence of gravitational waves.
The research involved 15 years of data from NANOGrav, which used telescopes across North America to search for the waves. Similar evidence was also found by other international teams of gravitational wave hunters. However, the research has not yet determined the exact sources of these low-frequency waves. Nevertheless, the discovery opens up new opportunities for studying the history of black holes and galaxies merging, providing insights into the biggest objects in the universe.
The background noise from these waves was found to be “louder” than expected, suggesting the possibility of more black hole mergers or other sources of gravitational waves that challenge current understanding. Scientists hope that further study of low-frequency gravitational waves will shed more light on the mysteries of the universe and expand our knowledge of cosmic archaeology.
This groundbreaking research highlights the progress being made in the field of astrophysics and our understanding of the universe. The study reminds us of the awe-inspiring power and beauty of the cosmos and the remarkable capabilities of human exploration and discovery.
The research article titled “The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background” was published in The Astrophysical Journal Letters.