Dark spots sometimes dot the surface of the Sun – magnetic storms that can last for days or weeks. But the storms on other stars can make those on the Sun look puny. They can be so monstrous that they can change the star’s brightness by quite a bit. An example is one of the stars of Cor Caroli – the Heart of Charles. As seen by the eye alone, the s…

The stars Kochab and Pherkad serve several roles. They’re part of the body of Ursa Minor, the little bear. They form the outer edge of the bowl of the Little Dipper. And they’re “guardians of the pole” – they circle around Polaris, the star that marks the north celestial pole. Both stars are giants – they’ve puffed up at the end of the prime phase …

A Chinese spacecraft that’s scheduled for launch as early as next month has a double destination: a “quasi-moon” of Earth and an asteroid that acts like a comet. The first destination for Tianwen-2 is an asteroid, Kamo’oalewa. It’s a chunk of rock no more than the length of two or three football fields. What makes it intriguing is that it weaves ar…

A beautiful triangle decorates the dawn sky tomorrow. Two of its points are easy to see: the crescent Moon and the planet Venus, the “morning star.” The final point is a bit tougher: the planet Saturn, to the upper right of the Moon. It’s just half of one percent as bright as Venus, but its proximity to the brighter bodies will help it stand out. S…

Two bright crescents team up in the early morning the next couple of days: the Moon and the planet Venus – the brilliant “morning star.” They’re quite low as twilight begins to paint the dawn sky. The Moon is an obvious crescent. The Sun illuminates only about one-sixth of the lunar hemisphere that faces our way – the crescent. It’s nighttime acros…

The story of a black hole in Cygnus, the swan, is like the tale of an angler – there’s the star it caught, and the one that got away. V404 Cygni is about 7800 light-years away. It appears fairly close to the star that marks the intersection of the swan’s body and wings, which is high in the sky at dawn. The system was first noticed in 1938, when it…

The most amazing object visible through a small telescope doesn’t look all that remarkable. In fact, it looks like a faint star. Yet that point of light packs the power of 10 trillion Suns – the power of a quasar. 3C 273 is the first quasar ever discovered. When astronomers first saw it, they thought it was just another star. It looks like a star, …

The mild nights of spring are good times for skywatching. Only one thing is missing: a great meteor shower. The best showers are clustered in fall and winter, with the Perseids of August sometimes joining the list. Although the season doesn’t offer a great shower, a pretty good one should reach its peak tomorrow night: the Lyrids. Under a dark sky,…

The Sun is four and a half billion years old – a third of the age of the universe. Compared to the stars in globular clusters, though, it’s a youngster. Those stars were born when the universe was young. An example is Messier 3 – a family of about half a million stars. The cluster is about 11.4 billion years old. That means its stars were born just…

The Lucy spacecraft is headed for the Trojan asteroids – big chunks of rock and metal that share an orbit with Jupiter. But it’s checking out some other sights along the way. This weekend, for example, it’ll pass just a few hundred miles from a body in the asteroid belt, between the orbits of Jupiter and Mars. Lucy is named for the fossilized remai…