A new study argues that dark matter and dark energy might be illusions caused by the universe’s forces fading over time.
For many years, scientists have thought that dark matter and dark energy make up most of the cosmos. A new study, however, challenges that long-held belief by proposing that these mysterious components might not exist at all. Instead, what appears to be dark matter and dark energy could actually result from the gradual weakening of the universe’s fundamental forces as it grows older.
The research, led by Rajendra Gupta, an Adjunct Professor in the Department of Physics at the University of Ottawa, suggests that if the core strengths of nature’s forces (like gravity) change slowly across time and space, they could account for the puzzling behaviors astronomers see—such as how galaxies rotate, evolve, and how the universe continues to expand.
Windows and mirrors embedded with liquid crystals can hide images that appear only when the right kind of light is shined on them. The technique, inspired by a 4000-year-old trick for building “magic mirrors”, may be a step towards developing better displays for 3D images.
A magic mirror or window looks transparent until a light is shined onto it to reveal a secret image. Craftspeople in ancient China and Japan made magic mirrors out of bronze that similarly hid images, but physicists only began to understand how they work around 15 years ago.
Felix Hufnagel at the University of Ottawa in Canada and his colleagues used those insights to build a new type of magic mirror and window. Their versions contain a state of matter known as a liquid crystal. While liquids flow freely and crystal atoms are organised in stiff grids, liquid crystals split the difference: their molecules are both fluid and arranged in patterns. READ MORE...
