SA Special Editions

Exceptionally massive and bright, the earliest stars changed the course of cosmic history

To make a star, gas and dust must fall inward. So why do astronomers see stuff streaming outward?

The surprising finding that even the youngest stars commonly exist in sets of two or three has revised thinking about the birth of star systems

Less massive than stars but more massive than planets, brown dwarfs were long assumed to be rare. New sky surveys, however, show that the objects may be as common as stars

Sunspot cycles--on other stars--are helping astronomers study the sun's variations and the ways they might affect Earth

Shock waves from the sun can trigger severe turbulence in the space around earth, endangering satellites and astronauts in orbit. A novel spacecraft is showing how space storms develop

When two stars smash into each other, it can be a very pretty sight (as long as you're not too close by). These occurrences were once considered impossible, but they have turned out to be common in certain galactic neighborhoods

In these systems, ultradense neutron stars feed on their more sedate companions. Such stellar cannibalism produces brilliant outpourings of x-rays and drastically alters the evolution of both stars

Some stars are magnetized so intensely that they emit huge bursts of magnetic energy and alter the very nature of the quantum vacuum

Several years ago astronomers came across a new type of starthat spews out unusually low energy x-rays. These so-called supersoft sources are now thought to be white dwarf stars that cannibalize their stellar companions and then, in many cases, explode

These paired stellar remnants supply exquisite confirmations of general relativity. Their inevitable collapse produces what may be the strongest explosions in the universe

Every time a gamma-ray burst goes off, a black hole is born