Hours of research by our editors, distilled into minutes of clarity.
Look around you. Where are you? Where is this place you are occupying? Somewhere in a room, maybe in a city on a continent on a planet orbiting a star in a galaxy among billions. But… where is all of that?
For perspective on the universe's absolute massiveness, watch this four-minute video. Beginning at a facility in Germany, the "camera" pulls back revealing the surrounding countryside, Germany itself, Europe, the Earth, and so on. At one point stars form galaxies and galaxies, at a distance, become as seemingly "small" as the individual stars.
She discovered that stars on the outer edges of galaxies were orbiting much faster than expected based on visible matter alone, implying the presence of unseen mass exerting gravitational force. Without dark matter, the outer stars in galaxies would fly off into space instead of staying in orbit.
The theory of general relativity, widely regarded as Einstein's most significant accomplishment, posits that mass and energy bend space and slow down time. One consequence is that massive objects, such as black holes, bend spacetime so much that light coming from behind the object wraps back around it.
The James Webb Space Telescope has discovered a galaxy that formed just 280 million years after the Big Bang. It is another in a series of increasingly ancient galaxies that, according to current formation models, should not have been able to form so quickly after the birth of the universe.
Depth perception is hard to achieve when looking out into space. For decades, two camps of astrophysicists have disagreed over the nature of the North Polar Spur, a radio-wave emitting arc above the Milky Way galaxy's plane. Was it close and relatively small? Or was it faraway and much more massive? New research utilizing X-ray mapping of the galaxy has helped clarify the existence of both so-called smaller Fermi bubbles and larger X-ray ones.
In 2011, three scientists won the Nobel prize for discovering “dark energy”, which they believed to be responsible for the accelerated expansion of the universe. But recently a group of astrophysicists from the University of Canterbury challenged this prevailing notion, and suggested that the original model is incorrect. This article details their alternative "timescape” model and dives into the debate about dark energy’s existence.
Astronomers discovered that galaxies rotate in ways that visible matter alone cannot explain, pointing to the existence of dark matter. According to current models, forming galaxies like the Milky Way would be impossible without it.
Though it makes up about 25% of the universe, dark matter can't be seen directly; its existence is inferred through its gravitational effects, like the unexpectedly fast rotation of galaxies. The concept began in 1933 but gained wide acceptance after Vera Rubin’s galaxy rotation studies in the 1970s.
Theoretical candidates, like sterile neutrinos, axions, and WIMPs from supersymmetry, may open the door to a new branch of particle physics that shapes the cosmos through gravity. Some of these particles may constantly pass through us, but interact too weakly for detection.
