StarDate

No one has found evidence of life anywhere else in the universe. But the chemistry of life is all around, in everything from the planets and moons of our own solar system to distant galaxies.

One location that contains a lot of that chemistry is IC 348 — a star cluster about a thousand light-years away, in Perseus. It’s part of a much larger complex known as the Perseus molecular cloud. The cloud contains several clusters of especially young stars.

The 400 known stars of IC 348, for example, are just two million years old. And most of them are encircled by the raw materials for making planets.

This year, astronomers in Spain reported the discovery of some of the basic building blocks of life in the gas and dust between the stars. Some of this material may be flowing into the young star systems, where it could be incorporated into new planets.

The compounds included water, carbon dioxide, and ammonia, along with acetylene, benzene, and other carbon-based molecules. These and others are the building blocks of amino acids, which are key building blocks of life. Later, the astronomers found one amino acid. So IC 348 is bursting with some of the ingredients for life.

Perseus is in the northeast this evening. IC 348 is about half way between the bright star Capella, to its lower left, and the brilliant planet Jupiter, to the upper right. We’ll talk about Jupiter tomorrow.
 

Script by Damond Benningfield

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UGC 2885 is the largest spiral galaxy yet seen in our cosmic neighborhood. It’s several times the diameter of our home galaxy, the Milky Way, and it contains several times as many stars. Yet the impact of all those stars is dwarfed by the part of the galaxy we can’t see: dark matter. In fact, it’s one of the galaxies that helped convince astronomers that dark matter exists.

Dark matter produces no energy at all, but its gravity pulls on the visible matter around it. That’s especially easy to notice in spiral galaxies like UGC 2885. Astronomers measure the motions of stars at various locations within the galaxy. They see that something is causing stars in the galaxy’s rim to orbit much faster than expected. That “something” is dark matter. It’s several times as massive as the visible stars and gas.

Vera Rubin and her colleagues paid special attention to UGC 2885 in the 1980s. Careful measurements showed that it’s dominated by a dark-matter halo — strong evidence that dark matter really does exist. So in her honor, UGC 2885 is also known as Rubin’s Galaxy.

This beautiful cosmic pinwheel is about 230 million light-years away, in Perseus. The constellation is in the northeast during the evening. Rubin’s Galaxy is at the edge of the stick-figure outline of the hero, to the upper right of the bright star Capella. But you need a good-sized telescope to pick it out.
 

Script by Damond Benningfield

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In mythology, Perseus was a hero. Today, we might give him a more dramatic title: monster killer. He dispatched not one, but two nasty creatures. As a result, he’s commemorated in the stars. His constellation is in the northeast at nightfall, above the bright star Capella.

Perseus was the son of Zeus, the king of the gods of Olympus, and a mortal woman. Polydectes, the king of Perseus’s home island, sent him to kill Medusa, one of the Gorgons — sisters with writhing snakes on their heads. One look at them turned the viewer to stone.

Perseus chopped off Medusa’s head. He then killed Cetus, a sea monster who’d been sent to ravage Ethiopia. Finally, Perseus used Medusa’s head to turn the king and his cronies to stone after they’d mistreated his mother. When Perseus died, Zeus placed him in the heavens.

The hero’s brightest star is Mirfak, a name that means “elbow.” It’s directly above Capella in early evening. It’s more than 500 light-years away. It’s more than 60 times the Sun’s diameter, and 5,000 times its brightness.

Mirfak is about 40 million years old — a mere infant. Yet its life is almost over. It’s about eight times the Sun’s mass. Such heavy stars burn out quickly. As Mirfak dies, it might expel its outer layers, leaving only a heavy white dwarf. On the other hand, it might blast itself to bits as a supernova, leaving a super-dense corpse known as a neutron star.
 

Script by Damond Benningfield

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LAUNCH CONTROL: Main engine start, six engines up and running. And lift-off! Lift-off of the Proton rocket and the Zarya control module. The International Space Station is under way.

The International Space Station was born 25 years ago today. The first piece of the station was launched from Baikonur Cosmodrome in Kazakhstan. It was built and launched by Russia, but paid for by the United States.

For years, it provided control, crew quarters, and storage. Today, it’s mainly a storage locker.

Zarya is a Russian word for “sunrise.” The module was based on the design of the first series of Russian space stations, called Salyut. It’s a steel can more than 40 feet long. It weighed more than 20 tons at launch, plus several tons of propellants.

It wasn’t alone for long. Space shuttle Endeavour delivered the second module, known as Unity, a couple of weeks later. Astronauts used a robotic arm to attach the two pieces. It took a couple of years for the station to really start to take shape, though. Today, it consists of dozens of major pieces. In all, they span more than the length of a football field, with a total mass of almost a million pounds.

But it all started with a single large can, delivered to orbit 25 years ago today.
LAUNCH CONTROL: 30 seconds into the flight, good first-stage performance. The Proton delivering 1.9 million pounds of thrust from its six engines. ...
 

Script by Damond Benningfield

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The Moon slides past the planet Saturn the next couple of nights. Saturn is to the upper left of the Moon as darkness falls tonight. It’ll be closer to the right of the Moon tomorrow night. The planet looks like a bright star.

Saturn is named for a Roman god. In ancient Greece, he was known as Cronus. He was the leader of the Titans, who came before the gods of Olympus.

Saturn is passing through Aquarius. The constellation is home to many stars that host their own planets. And like Saturn, many of those worlds have more than one name.

All of the planets bear the names of their stars followed by a letter of the alphabet, starting with “b.” The letters indicate the order of a planet’s discovery around its star.

Over the past few years, the International Astronomical Union has been assigning formal names to exoplanets. The latest batch was announced this year. It includes two planets in Aquarius.

The names were submitted as part of a competition. They come from many cultures and eras.

The planet HATS-72b was named Zembretta, after a tiny island off the coast of Tunisia. And WASP-69b was named Makombe, after a stream that feeds a major river in Cameroon. Both planets are giants — the size of Saturn or bigger. And they’re quite close to their parent stars, so they’re quite hot.

There’s no guarantee that astronomers will actually use the new names. But they offer a new way to think about some far-off worlds.
 

Script by Damond Benningfield

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Three of the five planets that are easily visible to the unaided eye are in decent view now, with one more just starting to join them. Brilliant Jupiter, the largest planet in the solar system, is in the east at nightfall. Saturn, the second-largest, is in the southwest at the same time, well to the upper left of the Moon. Venus, the “morning star,” is in the southeast at dawn. And little Mercury is about to climb into the western sky during evening twilight.

Only one planet is missing: Mars. It’s passing directly behind the Sun today. It won’t return to view, in the morning sky, until next year.

That’s an inconvenience not just for skywatchers. It’s also a problem for the scientists and engineers who operate Mars landers, rovers, and orbiters.

When Mars is within two degrees of the Sun — the width of your finger held at arm’s length — the Sun can interfere with radio transmissions. This year, that period spans November 11th through the 25th.

Scientists beamed up two weeks’ of commands before the blackout period. Some instruments were shut down. Others will record their observations for playback later on. And if anything goes wrong, the craft can go into “safe mode” — they shut down most operations and wait to hear from Earth.

So flight controllers are anxiously waiting for Mars to move away from the Sun a couple of days after Thanksgiving — allowing their charges to get back to work.
 

Script by Damond Benningfield

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For fans of rail travel, “meteor train” may evoke images of a classic rail line of the early 20th century, or of Amtrak’s modern-day silver meteor train. For skywatchers, though, the phrase conjures different images: glowing streaks in the night sky than can last for a long time.

And tonight is a good night to look for them, because the Leonid meteor shower should be at its peak.

A meteor shower flares to life when Earth flies through the path of a comet. Tiny bits of rock and dirt shed by the comet slam into the atmosphere at high speeds. They quickly vaporize, forming the trails of light known as meteors.

Most meteors last only a second or two. But a few leave behind longer-lasting trails, known as persistent trains. They’ve been known to keep glowing for several minutes.

Recent studies say they may form when metal-rich bits of comet dust burn up. They react with oxygen in the upper atmosphere. That continues to heat the atmosphere well after the meteor itself has vanished. The trains seem to be a little more common among slower meteors than faster ones.

The trains also produce radio waves. Today, scientists are using an array of radio telescopes to study these rare but beautiful sights — bright trains chugging across the sky.

The Leonids should be at their best between midnight and dawn. Under dark skies, you might see up to a dozen or so meteors per hour — and perhaps a few persistent trains.
 

Script by Damond Benningfield

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A meteor shower with a Jekyll-and-Hyde personality should be at its best over the next few nights. This is one of its “Jekyll” years, though, so it’ll be meek. At best, you might see 10 or so meteors per hour.

The Leonid meteors are spawned by Comet Tempel/Tuttle 55. It was discovered in 1866, and it returns to the inner solar system once every 33 years or so. As it orbits the Sun, it sheds comet dust — small bits of rock and dirt. Earth flies through trails of this material every November. The debris rams into our atmosphere, vaporizing as the glowing streaks of light known as meteors.

The shower shows its “Mr. Hyde” personality when the comet is closest to Earth, so the streams of particles are thickest. In 1866, for example, it produced up to a hundred thousand meteors per hour — the most spectacular meteor “storm” ever recorded.

Now, though, Tempel/Tuttle is far away, so the shower is puny. It’s expected to reach its peak tomorrow night. The best view comes in the hours before dawn, when your part of Earth turns most directly into the meteor stream. A second peak is possible on Monday night.

The shower is named for Leo, because the meteors appear to “rain” into the atmosphere from that direction. But they can bolt across any part of the sky, so you don’t have to look at Leo to see them. Find a dark, safe skywatching spot, bundle up against the chill, and watch the sky — for a meek showing of Leonid meteors.
 

Script by Damond Benningfield

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Astronomers have found planets orbiting all kinds of stars: big and small, young and old, and even dead. But they haven’t found many stars in globular clusters — tight balls of hundreds of thousands or millions of stars. In fact, they’ve confirmed only one planet in the Milky Way’s 150 globulars.

In part, that may be because it’s hard to make planets there. Globulars are the oldest residents of the Milky Way. Some date to less than a billion years after the Big Bang. So when the clusters were born, there weren’t many heavy elements for making planets. Those elements were created inside early stars, then expelled into space, where they could be incorporated into later generations of stars and planets.    

If planets tried to form in globulars, they might not have had a chance. Stars in the clusters are tightly packed. Encounters between stars might have stirred up the clouds of planet-making material. And even if planets did form, they could have been kicked out of their parent clusters by similar encounters.

On the other hand, globulars are a long way away, so perhaps they do have planets, but they’re just too hard to see.

The only known planet is a giant — heavier than Jupiter, the giant of our own solar system. It orbits a pair of dead stars. It’s likely that the planet was born elsewhere, then captured by the dead stars during a close encounter — giving them the only known planet in any globular cluster.
 

Script by Damond Benningfield

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Venus will reign as the “morning star” for the rest of the year. It’s the shiniest planet in the solar system. Because of its global cloud cover, it reflects more than three-quarters of the sunlight that strikes it. That’s compared to about 30 percent for Earth and just 12 percent for the Moon.

Scientists have found a brighter planet about 230 light-years away, in the constellation Sculptor. LTT 9779b reflects as much as 80 percent of the light from its parent star. That makes it the most reflective planet yet seen anywhere.

It’s classified as an “ultra-hot Neptune.” It’s a little bigger and more massive than Neptune, the Sun’s fourth-largest planet. But while Neptune is the Sun’s most remote major planet, LTT 9779b is so close in that it’s getting roasted — the dayside temperature hits more than 3,000 degrees.

At that temperature, the atmosphere may be saturated with silicates — the material that makes glass and sand. It also may contain metals, including titanium. In the lower atmosphere, these compounds are gasses. But at the top of the atmosphere, they condense to form clouds.

Scientists say the clouds are a surprise. At such high temperatures, the planet’s atmosphere should be blowing off into space. But the metals in the clouds may act as a protective lid, making the atmosphere harder to strip away — and keeping LTT 9779b intact.
 

Script by Damond Benningfield

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