Scientists Detect Low-Frequency Gravitational Waves from Supermassive Black Holes

Key Highlights :

1. Scientists have observed the faint ripples caused by the motion of black holes for the first time.

2. These ripples are called low-frequency gravitational waves.

3. They were able to "hear" what are called low-frequency gravitational waves - changes in the fabric of the universe that are created by huge objects moving around and colliding in space.

4. The results released this week included 15 years of data from NANOGrav, which has been using telescopes across North America to search for the waves.

5. Other teams of gravitational wave hunters around the world also published studies, including in Europe, India, China and Australia.

     For the first time, scientists have detected low-frequency gravitational waves created by supermassive black holes. These waves, which ripple through the fabric of space-time, are caused by huge objects moving around and colliding in space. The discovery was made by the NANOGrav collaboration, who reported their findings in The Astrophysical Journal Letters.

     Gravitational waves were first predicted by Albert Einstein in 1915, when he theorized that when heavy objects move through space-time, they create ripples in the fabric of the universe. In 2015, scientists used the Laser Interferometer Gravitational-Wave Observatory (LIGO) to detect gravitational waves for the first time, showing that Einstein was right. However, the LIGO experiment only detected waves at high frequencies.

     In order to detect low-frequency gravitational waves, scientists had to search for waves that take years or even decades to cycle up and down. These waves are believed to come from supermassive black holes, which are billions of times the mass of our sun. When galaxies across the universe collide and merge, their enormous black holes come together and get locked into a dance before they finally collapse into each other. As they circle around in these pairings, they send off gravitational waves.

     In order to detect these waves, scientists used telescopes to observe dead stars called pulsars, which send out flashes of radio waves as they spin around in space. By analyzing tiny changes in the pulsars’ ticking rate, scientists were able to tell that gravitational waves were passing through. The NANOGrav team monitored 68 pulsars across the sky using the Green Bank Telescope, the Arecibo telescope, and the Very Large Array.

     The background noise they found was “louder” than some scientists expected, which could mean that there are more, or bigger, black hole mergers happening out in space than we thought. Continuing to study these low-frequency gravitational waves could help us learn more about the biggest objects in our universe and open new doors to “cosmic archaeology” that can track the history of black holes and galaxies merging all around us.

Continue Reading at Source : abc7