Planets can really get around. In the early days of our own solar system, for example, the giant outer planets may have moved toward or away from the Sun by hundreds of millions of miles. And many of the planets seen in other star systems probably have spiraled inward from their birthplaces. One example is a planet orbiting the star Gliese 1214. Th…

A star system in the constellation Ophiuchus keeps blowing up. Every 15 years or so, it flares about 1500 times brighter than average. And it could be building up to an even bigger outburst – a final act that would make it shine billions of times brighter. RS Ophiuchi consists of two stars. One of them is a white dwarf – a small, hot stellar corpse…

For a few weeks in the spring of 1764, Charles Messier was a star-cluster-discovering machine. He found five globular clusters in Ophiuchus, the serpent bearer. He cataloged them as Messier 9, 10, 12, 14, and 19. Messier wasn’t interested in the clusters – or even in the stars. Instead, he was looking for comets. At the time, finding a comet was a …

Barnard 68 is one of the darkest objects in our section of the galaxy. It’s a small cloud that absorbs the light of the stars behind it, so it looks like a dark “hole” in the Milky Way. Before long, though, that void may shine with the warmth of newly forming stars. Barnard 68 is a Bok globule – a small, dark sphere of gas and dust. It’s about 500 …

The gods of ancient Greece had complicated relationships. As an example, consider Ophiuchus. He’s represented by a constellation that passes across the southern sky on summer evenings. The constellation represented Asclepius, the god of medicine and the son of the god Apollo. In one version of the story, Asclepius killed a snake with his staff. But…

Earth has something in common with Titan, the largest moon of Saturn. They’re the only two bodies in the solar system with liquids flowing and ponding on the surface. In the case of Earth, that liquid is water. But on frigid Titan, it’s liquid hydrocarbons – methane and ethane. Titan is the second-largest moon in the solar system – a bit bigger tha…

One of the best-known meteor showers will be at its best the next couple of nights. Unfortunately, the gibbous Moon will be in the sky during the best hours for meteor watching. That will spoil the view of all but the brightest meteors. Perseid meteors are spawned by Comet Swift-Tuttle. The comet orbits the Sun once every 133 years or so. As it pli…

Social media may go wild the next few days – filled with reports of UFOs in the early morning sky. Ignore them. The objects are fully identified. They’re the planets Venus and Jupiter – the brightest objects in the night sky after the Moon. They’re crossing paths, as Jupiter pulls away from the Sun as seen from Earth, and Venus drops toward it. Ven…

Based on how bright the stars look to our eyes alone, Deneb ranks among the 20 brightest stars in the night sky. Because the stars are at different distances, though, that ranking is a little misleading. If we could arrange them based on their true brightness, Deneb would outshine them all. In fact, it might be the brightest of all the stars that a…

Altair is a close neighbor – just 16.7 light-years away. Only about 50 star systems are closer. And it’s bigger and brighter than the Sun, so it’s easy to study. Even so, not even the largest individual telescopes can see it as more than a bright dot. Yet astronomers have managed to take a fairly detailed picture of it. They’ve done so with a techn…