An example of a cosmic-ray extensive air shower recorded by the Subaru Telescope. The highlighted tracks, which are mostly aligned in similar directions, show the shower particles induced from a high-energy cosmic ray. Credit: NAOJ/Hyper Suprime-Cam (HSC) Collaboration
“Oh My God,” someone must have said in 1991 when researchers detected the most energetic cosmic ray ever to strike Earth. Those three words were adopted as the name for the phenomenon: the Oh-My-God particle. Where did it come from?
Albert Einstein during a lecture in Vienna in 1921.
Credit: National Library of Austria/F Schmutzer/Public Domain
Near the end of his life Einstein worked tirelessly to find a way to unite electromagnetism with gravity. He could not, and never did, the notes scattered on his desk scrawled with fruitless probes and useless hypotheticals. Indeed, Einstein passed without even understanding why the two forces could not be united.
This all-sky Fermi view includes only sources with energies greater than 10 GeV. From some of these sources, Fermi's LAT detects only one gamma-ray photon every four months. Brighter colors indicate brighter gamma-ray sources. Credit: NASA/DOE/Fermi LAT Collaboration
It started with a simple experiment that was all the rage in the early 20th century. And as is usually the case, simple experiments often go on to change the world, leading Einstein himself to open the revolutionary door to the quantum world.
Hubble image of SDSSJ0146-0929, a galaxy cluster that is massive enough to severely distort the spacetime around it. There's the mass of the visible stars and gas, but there's also a hidden amount of dark matter that adds to the cluster's mass. Credit: ESA/Hubble & NASA; Acknowledgment: Judy Schmidt
In Einstein’s famous theory of relativity the concepts of immutable space and time aren’t just put aside, they’re explicitly and emphatically rejected. Space and time are now woven into a coexisting fabric. That is to say, we truly live in a four-dimensional universe. Space and time alone cease to exist; only the union of those dimensions remains.
Researchers crunched Einstein's theory of general relativity on the Columbia supercomputer at the NASA Ames Research Center to create a three-dimensional simulation of merging black holes. Image Credit: Henze, NASA
The theory of relativity is at once simple and elegant but also maddeningly nonintuitive. There’s no need to get into the full guts and glory of that theory here, but there is one feature of Einstein’s work that takes center stage, and would eventually lead him into a complete reshaping of Newton’s gravity, altering our very conceptions of the fabric of the universe.
These are just four of the women physicists profiled in "Her Space, Her Time": Henrietta Swan Leavitt, Cecilia Payne-Gaposchkin, Vera Rubin and Claudia Alexander. (Credits: Wikimedia; Smithsonian Institution; Rubin photo by Mark Godfrey, courtesy of AIP Emilio Segre Visual Archives; NASA)
But who else? In a new book titled “Her Space, Her Time,” quantum physicist Shohini Ghose explains why women astronomers and physicists have been mostly invisible in the past — and profiles 20 researchers who lost out on what should have been Nobel-level fame.
“This issue around having low representation of women in physics is something that’s common all around the world,” Ghose says in the latest episode of the Fiction Science podcast. “And I’ve certainly faced it in my own experiences as a physicist growing up. I really didn’t know of any woman physicist apart from Marie Curie.”
Physicists have shown that simulating models of hypothetical time travel can solve experimental problems that appear impossible to solve using standard physics. Credit: Yaroslav Kushta via Getty Images
Time travel. We’ve all thought about it at one time or another, and the subject has been explored extensively in science fiction. Once in a while, it is even the subject of scientific research, typically involving quantum mechanics and how the Universe’s four fundamental forces (electromagnetism, weak and strong nuclear forces, and gravity) fit together. In a recent experiment, researchers at the University of Cambridge showed that by manipulating quantum entanglements, they could simulate what could happen if the flow of time were reversed.
Illustration of how anti-hydrogen can test gravity. Credit: National Science Foundation
It’s a basic fact we’ve all learned in school. Drop any object, be it a baseball, feather, or cat, and it will fall toward the Earth at exactly the same rate. The cat will fortunately land on its feet thanks to a bit of feline grace, but the point is that everything falls at the same rate under gravity. It doesn’t matter what an object is made of, or how heavy it is. While we’ve all been taught this fact, calling it a fact was, until recently, a bit of a lie.
Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser
At the heart of large galaxies like our Milky Way, there resides a supermassive black hole (SMBH.) These behemoths draw stars, gas, and dust toward them with their irresistible gravitational pull. When they consume this material, there’s a bright flare of energy, the brightest of which are quasars.
While astrophysicists think that SMBHs eat too slowly to cause a particular type of quasar, new research suggests otherwise.