Category Astronomy/Space

Thought to make up 85% of matter in the universe, dark matter is non-luminous and its nature is not well understood. While normal matter absorbs, reflects, and emits light, dark matter cannot be seen directly, making it harder to detect. A theory called “self-interacting dark matter,” or SIDM, proposes that dark matter particles self-interact through a dark force, strongly colliding with one another close to the center of a galaxy.

In work published in The Astrophysical Journal Letters, a research team led by Hai-Bo Yu, a professor of physics and astronomy at the University of California, Riverside, reports that SIDM simultaneously can explain two astrophysics puzzles in opposite extremes.

“The first is a high-density dark matter halo in a massive elliptical galaxy,” Yu said...

Phenomena called ‘Steve’ and ‘picket fence’ are masquerading as auroras, graduate student argues

While auroras occur at high latitude, the associated phenomena Steve and the picket fence occur farther south and at lower altitude. Their emissions also differ from aurora...

Our sun actively produces solar flares that can impact Earth, with the strongest flares having the capacity to cause blackouts and disrupt communications—potentially on a global scale. While solar flares can be powerful, they are insignificant compared to the thousands of “super flares” observed by NASA’s Kepler and TESS missions. “Super flares” are produced by stars that are 100–10,000 times brighter than those on the sun.

The physics are thought to be the same between solar flares and super flares: a sudden release of magnetic energy...

Galactic winds enable the exchange of matter between galaxies and their surroundings. In this way, they limit the growth of galaxies, that is, their star formation rate...