StarDate

The Moon will briefly cover up the tail of the sea-goat tonight – Deneb Algedi, the brightest star of Capricornus. The sequence will be visible across much of the United States.

This vanishing act is…

The planet Jupiter will slide past one of the brighter stars of Gemini the next few mornings. At their closest, they’ll be separated by just a fraction of a degree.

The star is Wasat – from an Arabic…

Water is the key ingredient for life on Earth. And as far as we know, it’s a key ingredient for life everywhere else in the universe as well. That shouldn’t be a problem, though, because there’s plen…

Earth is the only body in the solar system with liquid water on its surface. But it’s not the only one where you can find water. In fact, water is everywhere – from comets and asteroids to the giant …

Water is all about extremes. The atoms that make up water molecules were forged in some of the hottest environments in the universe. But most of the molecules formed in the cold of deep space.

A wate…

To have a strong heart, you naturally need strong arteries. And that’s not a problem for Antares, the heart of the scorpion. It’s flanked by two fairly bright stars that historically have shared a na…

A spacecraft that’s on it way to Jupiter is “pinballing” around the solar system, getting an extra “kick” as it zips close to the planets. It’ll get the next kick tomorrow, from Venus.

The spacecraft…

Only a few of the thousands of known planets in other star systems have ever been seen. Most exoplanets are discovered through their effects on their parent stars. But a system in Pegasus is a major …

A recently discovered planet is facing its final days. It’s evaporating, leaving a trail of debris that stretches halfway along its orbit.

The planet is known by a catalog number – BD +05 4868 Ab. It…

The Sun isn’t bothered by much. That’s because it travels through the Milky Way on its own. But most of the stars in the galaxy have at least one companion star. And the interactions between them can…

Mars is dry, cold, and quiet. But that hasn’t always been the case. Billions of years ago it was much busier – and perhaps a comfortable home for life.

Mars has had three major geological ages. The o…

Every pilot knows to check the weather before takeoff – no one wants to fly into a storm. And in the future, they might want to check the space weather as well. Storms on the Sun can interfere with t…

As Earth was thawing out at the end of the last ice age, it was hit by a powerful blast from the Sun. The storm would have triggered spectacular displays of the northern and southern lights. And it l…

If you watch the stars on a dark night, it’s easy to think of the sky as a great dome. But as the night goes on, the dome rotates. New stars rise in the east, while others disappear in the west. So a…

Many “open” star clusters arch high overhead on summer nights. They’re lined up along the glowing band of the Milky Way – the outline of our home galaxy. Each cluster is a family of stars – from a fe…

Human eyes are perfectly tuned to see sunlight. But that’s a thin slice of the total range of light. As a result, we miss a lot of what’s out there – even objects that are big and close.

A recently d…

Many centuries ago, people knew of only seven metals. That also was the number of known “planets” – the five true planets that are visible to the naked eye, plus the Sun and Moon. So each metal was a…

Early risers are in for a treat tomorrow. Venus, Jupiter, and the twins of Gemini congregate around the Moon. The group climbs into good view a couple of hours before dawn. Venus is close to the lowe…

The crescent Moon will slide past three bright planets over the next three mornings, growing thinner as it does so. First up is Jupiter, the largest planet in the solar system. It looks like a bright…

The Moon butts up against the tip of one of the horns of Taurus early tomorrow. They’ll appear to almost touch as they climb into good view, around 2:30 or 3 a.m. They’ll be closest as viewed from th…