Mars is about to dodge a big snowball — a comet that will swing just 82,000 miles above the planet’s surface on Sunday. That’s just a third of the distance between Earth and the Moon, so it’s quite a close call.
Until the middle of the 19th century, the stars were little more than mysterious points of light. Astronomers could plot a star’s position in the sky, or record changes in its brightness, but that was about all
A few of our stellar neighbors are hard to miss. Vega, which passes high overhead on August evenings, is just 25 light-years away. And Sirius, the brightest star in all the night sky, is nine light-years away.
In a time when astronomers are studying galaxies that are billions of light-years away, you might think that we know everything there is to know about our own cosmic neighborhood.
The center of the Milky Way is already crowded with stars. But in a few million years, tens of thousands more could flare to life in a region known as the Brick. It’s a vast cloud of cold, dark gas and dust that’s shaped like a brick.
One of the first items on almost any amateur astronomer’s “to-do” list is completing the Messier marathon — looking at all 110 objects cataloged by Charles Messier. Messier himself began the first marathon 250 years ago.
There’s nothing like a trip to the mountains to escape the summer heat — whether you’re here on Earth or on Venus, our nearest planetary neighbor.
At Christmas of 1934, a bright “new” star exploded to life in Hercules. For a few days, it was one of the brightest stars in the night sky. It made the front pages of newspapers, and astronomers tracked it for months as it slowly faded from sight.
A white dwarf sounds harmless enough. It’s the small, dead core of a once-normal star like the Sun. But to a close companion star, a white dwarf is anything but harmless.
Our solar system can be a dangerous place. The most striking evidence of that came 20 years ago today, when the first fragment of a shattered comet blasted the planet Jupiter.