“It’s mind-boggling to actually witness material orbiting a massive black hole at 30% of the speed of light,” marveled Oliver Pfuhl, a scientist at the Max Planck Institute for Extraterrestrial Physics.
In 2018, astronomers discovered several bizarre objects at the Galactic Center using 12 years of data taken from W. M. Keck Observatory on Mauna Kea, Hawaii. The objects are concealing their true identity behind an opaque screen of dust; they look like gas clouds, but behave like stars. “These compact dusty stellar objects move extremely fast and close to our Galaxy’s supermassive black hole. It is fascinating to watch them move from year to year,” said astronomer Anna Ciurlo at UCLA. “How did they get there? And what will they become? They must have an interesting story to tell.” (more…)
“The fate of black holes in a quantum theory of gravity is, in my view, the most important problem in theoretical physics,” said Jorge Pullin, the Horace Hearne professor of theoretical physics at LSU.
Astronomers studying the motions of galaxies and the character of the cosmic microwave background radiation came to realize in the last century that most of the matter in the universe was not visible. About 84 percent of the matter in the cosmos is dark matter, much of it located in halos around galaxies. It was dubbed dark matter because it does not emit light, but it is also mysterious: it is not composed of atoms or their usual constituents like electrons and protons.
The coldest, darkest reaches of our Solar System – a region still to be visited by human spacecraft – is a strange, frigid cloud that contains material from other stars and an unconfirmed object known as Planet Nine that may actually be a planet-mass black hole. This forbidding uncharted region, an enormous bubble of material encasing the planets and our Sun, is known as the Oort Cloud. This far-away shell surrounding our Solar System underscores Edwin Hubble’s observation in 1936 that “with increasing distance, our knowledge fades, and fades rapidly. Eventually, we reach the dim boundary—the utmost limits of our telescopes. There, we measure shadows.”
Astronomers may soon be able to confirm the existence of a primordial black hole –gravity wells formed just moments after the Big Bang–in our Solar System with gravitational-wave experiments that will look back to a time before the formation of the first stars. “Ancient black holes would give us access to physics we would never otherwise be able to do,” wrote Dan Hooper, head of the theoretical astrophysics group at FermiLab, in an email to The Daily Galaxy. “If primordial black holes are real,’ he wrote, “they’d have potential to solve a whole host of the biggest problems in cosmology, not the least being the mystery of dark matter, considered to be the backbone to the structure of the universe.”