“I spent an hour just staring at this image,” lead researcher, astronomer Pieter van Dokkum of Yale University says as he recalls first seeing the Hubble image of NGC 1052-DF2, a galaxy completely void of dark matter. “This thing is astonishing, a gigantic blob so sparse that you see the galaxies behind it. It is literally a see-through galaxy. It’s so rare, particularly these days after so many years of Hubble, that you get an image of something and you say, ‘I’ve never seen that before.”
What if gravity is an illusion, a cosmic side effect of something else going on at deeper levels of reality? The classical theory of gravity is in dire need of new approaches, since it doesn’t combine well with quantum physics. Both theories, crown jewels of 20th century physics, cannot be true at the same time. A Dutch theoretical physicist and string theorist, Erik Verlinde, proposes a starkly different theory – the theory of emergent gravity. “For me gravity doesn’t exist,” he says. “We might be standing on the brink of a new scientific revolution that will radically change our views on the very nature of space, time and gravity.”
“We do not know what dark matter is, but if it has anything to do with any scalar particles, it may be older than the Big Bang,” says astrophysicist Tommi Tenkanen at the Johns Hopkins University, who was not part of a 2019 University of Tokyo study that proposed the axion as a candidate for dark matter. The only fundamental scalar quantum field that has been observed in nature is the Higgs field-a field of energy that is thought to exist in every region of the universe.
Miguel Zumalacarregui was a Marie Curie Global Fellow at the Berkeley Center for Cosmological Physics prior to joining The Max Planck Institute for Gravitational Physics (Einstein Institute) in 2021. A Google Scholar, his research is directed towards finding new theoretical and observational approaches to the problem of cosmic acceleration, the nature of dark matter, and their connections to fundamental physics.
One new theory, says physicist Michio Kaku, is that the as yet undetected dark matter of the universe may be ordinary matter that makes up stars, planets and galaxies in a parallel universe. “If a galaxy is hovering above in another dimension,’ says Kaku, “we would not be able to see it. It would be invisible, yet we would feel its gravity. Hence, it might explain dark matter.”
In 2018 a team of physicists linked to the massive IceCube Observatory detector buried under the South Pole, and to a command center at Penn State University, advanced satellites, and several land-based observatories, pinpointed the first known cosmic source of a neutrino, a ghost-like particle that passes through virtually all matter on Earth. It’s estimated that each second there are about 100 billion neutrinos passing through your body. (more…)