What is the next challenge of “Laser Interferometer Gravitational Wave Observatory”, the first in the world to observe gravitational waves?


US research facility “ Laser Interferometer Gravitational-Wave Observatory (LIGO) ” where more than 1000 scientists are experimenting with over 1 billion dollars The scientific journal Scientific American summarizes the achievements and future goals that have been given so far.

Gravitational Waves Discovered from Colliding Black Holes-Scientific American

In a paper on general relativity written in 1916, physicist Albert Einstein predicted the existence of gravitational waves , a phenomenon where space-time distortion propagates at the speed of light as waves .

In the 1960s, half a century later, many scientists tried to observe gravitational waves to confirm Einstein's prophecy, but none of them made remarkable results. Gravity waves will finally be observed directly in February 2016, when 100 years have passed since Einstein's prediction of its existence for another 50 years since the full-scale observation of gravity waves began, and its existence can be confirmed have become. At this time, the US observation facility “LIGO” succeeded in observing gravity waves.

Finally succeeded in observing gravitational waves, and the possibility of space research to expand greatly by supplementing space observation with light-GIGAZINE

Since observing gravity waves for the first time in 2016, LIGO has succeeded in observing gravity waves 23 times in total through three observation projects. Of these, 20 were the same black hole collisions as the first, and 2 were neutron star collisions. The most recent observations in August 2019 detected gravitational waves that were most likely generated by the first “ black hole-neutron star collision ” in the world.

As a result of these achievements, in 2016, the black hole collision that blew physicists around the world became a completely “boring event” in recent years. Professor Daniel Holz, an astrophysicist at the University of Chicago, said, “The study of black hole collision is now a statistically processed event, but what about gravitational waves going next? “It's a fascinating study to see how big or small the impact is compared to past observations.”

On the other hand, there are many new discoveries. At 6:34 on August 28, 2019 (at the time of the global agreement), LIGO observed the gravitational waves generated by the collisions between the black holes, but the exact same gravitational waves were detected again 21 minutes later.

Gravitational wave wavelengths rarely coincide by chance. Therefore, Robert Rutridge, an astronomer at McGill University who saw this announcement, tweeted that he had leaked unintentionally, “Wait, what?

Subsequent investigation revealed that these two observation records are likely to have been caused by gravitational waves generated by collisions of the same celestial body in different directions. The fact that what was emitted in different directions was observed at the same place means that the gravity wave is bent somewhere. For that reason, astronomers have speculated that gravitational waves are also bent by gravity , like a gravitational lens where light is bent by gravity .

The black holes and neutron stars that LIGO has observed through gravity waves so far are all considered to be celestial bodies formed when a huge star dies. Then, what LIGO is challenging for the next observation is the supernova explosion that prompts the birth of a new star. However, the gravitational waves generated by supernova explosions are so weak that they can only be observed by supernova explosions that occurred in the Milky Way Galaxy where the solar system is located.

Holz said, “Supernova explosions occur in the Milky Way Galaxy once every century, so LIGO has never been observed in the four years since it began full-scale operation. I'll have to wait, but someday I'll definitely get up, 'he said and looked forward to seeing a big event once every 100 years.

In the future, LIGO plans to upgrade to Advanced LIGO Plus (ALIGO +) , which has greatly improved accuracy with investment from the National Science Foundation, etc., and around 2023 when the renovation of the facility is over, `` 1 per hour Gravity waves can be detected at the pace of the times. '

in Science, Posted by log1l_ks