The annual Geminid meteor shower peaks this year on Dec. 13th and 14th. Researchers don't fully understand the Geminids, and new measurements make it more mysterious than ever.
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NASA-supported researchers have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism, which lives in California's Mono Lake, substitutes arsenic for phosphorus in the backbone of its DNA.
Some of the comets in our Solar System probably came from other stars, according to new research by NASA-supported scientists. Studying these 'alien' comets, they say, could reveal new information about stellar systems far, far away.
NASA's Hubble Space Telescope has captured rare images of a suspected asteroid collision. The snapshots show a bizarre X-shaped object at the head of a comet-like trail of material. Their findings will be published in the Oct. 14th issue of Nature.
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The western evening sky features several bright stars and planets in late May. This view, on May 22, is roughly an hour after sunset, and includes the crescent Moon. The Moon will move up and to the left on succeeding nights as the crescent grows fatter.
Text ©2015 The University of Texas at Austin McDonald Observatory
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
The crescent Moon stands at the middle of a beautiful celestial grouping this evening. That grouping includes the planets Venus and Jupiter — the second- and third-brightest objects in the night sky — and several bright stars.
Venus is to the lower right of the Moon. It’s the dazzling “evening star,” so there’s no way to miss it. In fact, it’s so bright that you might mistake it for an approaching airplane with its landing lights turned on. Keep an eye on it for a bit, though, and you’ll see that it doesn’t move — it maintains its position relative to the other astronomical objects around it.
Jupiter is about the same distant to the upper left of the Moon. It, too, is extremely bright — brighter than any true star in the night sky. That’s because Jupiter is the biggest planet in the solar system, and because it’s covered by clouds that reflect a lot of sunlight. It’s only about a tenth as bright as Venus, though, because it’s hundreds of millions of miles farther.
A few stars are part of the evening tableau as well. Procyon, the brightest star of Canis Minor, the little dog, stands below the Moon. And Pollux and Castor, the twins of Gemini, are off to the right of the Moon.
So enjoy this beautiful grouping throughout the evening. It’s especially pretty as the last of the twilight adds a bit of color to the view.
And since that’s a lot of stuff to keep track of, we’ve posted a chart on our web site.
Script by Damond Benningfield, Copyright 2015
Venus is slowing down.
Our closest planetary neighbor takes about 243 Earth days to make a single turn on its axis — far longer than any other planet in the solar system. But observations by Venus-orbiting spacecraft showed that from 1986 to 2012, that time increased by about six-and-a-half minutes.
We can’t see the surface of Venus from Earth because the planet is blanketed by clouds. In the 1980s, though, the Magellan spacecraft used radar to peer through the clouds. It mapped thousands of surface features. Scientists used the motions of those features to measure Venus’s rotation rate to within a few seconds.
A few years ago, another craft, Venus Express, found that those features weren’t where they were supposed to be. The features hadn’t actually moved, though. Instead, the time of a single rotation had gotten longer — by six-and-a-half minutes.
Scientists are still trying to understand the reason for the change. Some of it is probably caused by the planet’s atmosphere. It’s about 90 times denser than Earth’s air, so as Venus turns, the atmosphere exerts a drag on the planet itself. And strong weather systems may magnify the effect.
But the atmosphere can’t explain the entire difference, so scientists are still pondering why Venus is slowing down.
And Venus teams up with the Moon to put on a grand showing this evening. Venus is the brilliant “evening star” to the right of the Moon as night falls. More tomorrow.
A massive ring system surrounds a giant planet in the star system J1407, as depicted in this artist's concept. The rings are hundreds of times wider than those of Saturn. A moon that's somewhere between the size of Earth and Mars appears to be embedded in the rings. Most of the ring system may disappear of the next few million years. [Ron Miller]
The planet Saturn is best known for its amazing rings. They span about two-thirds of the distance from Earth to the Moon, and seen from the right angle they can double Saturn’s brightness. If you have a telescope, you can see them yourself right now. Saturn is low in the southeast at nightfall, and looks like a bright golden star.
Yet Saturn’s rings are puny compared to those that encircle a planet in the constellation Centaurus. Those rings are hundreds of times wider than Saturn’s — wide enough to span the distance from Earth to the Sun.
The system is more than 400 light-years away. It’s known by a catalog number — J1407. A few years ago, automated telescopes recorded a series of eclipses of the star. Its light dimmed by up to 95 percent, sometimes in as little as a few hours.
Earlier this year, astronomers from the U.S. and England produced a detailed profile of what was going on. They found that the eclipses were caused by a giant planet with a giant ring system passing in front of the star. There are at least 37 rings. One big gap in the rings probably was cleared out by a moon that’s between the size of Mars and Earth.
The rings probably won’t last long, though. The star system is only about 16 million years old, so things are still taking shape. Over the next few million years, much of the ring material may coalesce to make more moons — depriving the young planet of its glorious rings.
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