Almost seven years ago (September 14th, 2015), researchers at the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves (GWs) for the first time. Their results were shared with the world six months later and earned the discovery team the Noble Prize in Physics the following year. Since then, a total of 90 signals have been observed that were created by binary systems of two black holes, two neutron stars, or one of each. This latter scenario presents some very interesting opportunities for astronomers.
If a merger involves a black hole and neutron star, the event will produce GWs and a serious light display! Using data collected from the three black hole-neutron star mergers we’ve detected so far, a team of astrophysicists from Japan and Germany was able to model the complete process of the collision of a black hole with a neutron star, which included everything from the final orbits of the binary to the merger and post-merger phase. Their results could help inform future surveys that are sensitive enough to study mergers and GW events in much greater detail.
Earlier this year, astronomers used microlensing and the Hubble Space Telescope to detect, for the first time, a rogue black hole that is about 5,000 lightyears away from Earth. Now, with more precise measurements, they have been able to determine an approximate mass of this hard-to-detect object. However, the surprisingly low mass means there’s a chance this object may not actually be a black hole.
There are a lot of amazing things in our Universe and a black hole is one of the most unknown. We don’t know for certain what happens inside a black hole and even the formation of supermassive black holes in the early universe is still being worked out. A group of physicists at Brookhaven National Laboratory have tackled this question and have come up with a possible solution to the mystery. The nature of dark matter may be resolved by their theory as well.
“The yet unanswered question of the nature of Dark Matter, and how primordial supermassive Black Holes could grow so fast in such a short amount of time are two pressing open questions in physics and astrophysics. Finding a common explanation for these observations is desirable and could provide us with insights into the inner workings of the Universe.”
Julia Gehrlein – Physicist at Brookhaven National Laboratory
Until recently, one of the closest orbiting each other pairs of supermassive blackholes was found in NGC 7727. That pair is about 89 million light-years away from Earth. Those black holes are only 1,600 light-years apart from each other. Another pair in OJ 287, about 3.5 billion light-years from Earth, are only separated by about 0.3 light years. Now scientists have discovered a pair orbiting each other at a distance of 200 AU to 2,000 AU apart, about 0.003 to 0.03 light years.
When two neutron stars collide, it creates a kilonova. The event causes both gravitational waves and emissions of electromagnetic energy. In 2017 the LIGO-Virgo gravitational-wave observatories detected a merger of two neutron stars about 130 million light-years away in the galaxy NGC 4993. The merger is called GW170817, and it remains the only cosmic event observed in both gravitational waves and electromagnetic radiation.
Astronomers have watched the expanding debris cloud from the kilonova for years. A clearer picture of what happens in the aftermath is emerging.
Both quantum computing and machine learning have been touted as the next big computer revolution for a fair while now. However, experts have pointed out that these techniques aren’t generalized tools – they will only be the great leap forward in computer power for very specialized algorithms, and even more rarely will they be able to work on the same problem. One such example of where they might work together is modeling the answer to one of the thorniest problems in physics: how does General Relativity relate to the Standard Model?
While black holes might always be black, they do occasionally emit some intense bursts of light from just outside their event horizon. Previously, what exactly caused these flares had been a mystery to science. That mystery was solved recently by a team of researchers that used a series of supercomputers to model the details of black holes’ magnetic fields in far more detail than any previous effort. The simulations point to the breaking and remaking of super-strong magnetic fields as the source of the super-bright flares.
In the history of science and physics, several scholars, theories, and equations have become household names. In terms of scientists, notable examples include Pythagoras, Aristotle, Galileo, Newton, Planck, and Hawking. In terms of theories, there’s Archimede’s “Eureka,” Newton’s Apple (Universal Gravitation), and Schrodinger’s Cat (quantum mechanics). But the most famous and renowned is arguably Albert Einstein, Relativity, and the famous equation, E=mc2. In fact, Relativity may be the best-known scientific concept that few people truly understand.
For example, Einstein’s Theory of Relativity comes in two parts: the Special Theory of Relativity (SR and the General Theory of Relativity (GR). And the term “Relativity” itself goes back to Galileo Galilee and his explanation for why motion and velocity are relative to the observer. As you can probably tell, explaining how Einstein’s groundbreaking theory works require a deep dive into the history of physics, some advanced concepts, and how it all came together for one of the greatest minds of all time!