StarDate

The first meteor shower of the year doesn’t waste time. It comes early, flares quickly, and disappears in a hurry. And it’s at its peak late tonight.

The Quadrantid shower gets its name from an old constellation. Quadrans Muralis represented an astronomical instrument used in the 18th century. When astronomers reworked the list of constellations in the 1920s, though, they dropped Quadrans Muralis. Most of its stars were incorporated into Boötes the herdsman.

By then, the shower had already taken the constellation’s name. That’s because if you trace its meteors, they all appear to “rain” into the sky from that region. So even though the constellation vanished, the meteor shower kept the name.

The Quadrantids form one of the best showers of the year. At their peak, you might see several dozen “shooting stars” per hour. Yet that rate lasts only a short time. That’s because the trail of “comet dust” that spawns the meteors isn’t very wide. So Earth plunges right through it — limiting the Quadrantids to a busy but quick showing.

For American skywatchers, this year’s Quadrantids should be at their best before dawn tomorrow. Unfortunately, the gibbous Moon will be shining brightly — overpowering all but the brightest meteors.

Even though it spoils the shower, the Moon does offer up a bit of a consolation. It’s close to Regulus, the heart of Leo, the lion — forming a beautiful pairing in the early morning sky.

Script by Damond Benningfield

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Earth begins the new year by snuggling close to the Sun. Early tomorrow, the Sun will be closest for the whole year — just 91 million miles away. That’s less than two percent closer than the average distance, though, so we really won’t notice the difference.

We do receive a little more sunlight, but Earth’s oceans and atmosphere do a good job of keeping the temperatures evened out.

The lopsidedness in a planet’s orbit is known as eccentricity. Earth’s orbit is pretty close to circular, so right now the eccentricity is low. But that’s not always the case.

The other planets of the solar system constantly tug at Earth — especially Jupiter and Saturn, the biggest and heaviest planets. Over a period of a hundred thousand years, they cause a sizeable change in the shape of Earth’s orbit.

At its maximum, the orbit is about four times more eccentric than it is today. During those times, the distance to the Sun varies by more than 12 million miles, so the orbit looks more stretched out. But at its minimum, the eccentricity is less than a third of what it is today. At those times, the distance to the Sun changes by just one million miles.

Today, the orbit is getting less eccentric. So there will be less change in our planet’s distance from the Sun in the coming centuries.

For this year, we’ll start moving away from the Sun by tomorrow afternoon. We’ll be farthest from it the day after another holiday: the Fourth of July.

Script by Damond Benningfield

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One of the strangest and most chaotic years any of us are ever likely to see comes to an end tonight. And we have to skip many of the usual year-end celebrations. But you can see the old year out — and the new one in — with a quiet celebration of your own. Just look to the midnight sky. It features a bright Moon, a fading planet, and the beautiful constellations of winter.

The Moon is high in the sky as the new year arrives. It’s only a couple of days past full, so it’s still big and bright. In fact, its glow overpowers many of the stars.

Only one planet is in view at that hour: Mars. It’s low in the west, and looks like a bright orange star. It’s lost a good bit of its brilliance from earlier in the year. But it’ll still be a beautiful sight as we head into 2021.

The constellation Orion is high in the south at midnight. It has lots of bright stars that shine through the moonlight. Look for its three-star belt, with orange Betelgeuse above and blue-white Rigel below.

And if you follow the line of the belt to the lower left, you’ll come to Sirius, the brightest star in the night sky.

And even though spring is almost three months away, one of the harbingers of the season is already in view. Leo, the lion, is well to the lower left of the Moon. Its mighty heart is marked by the bright star Regulus.

So enjoy the beauty of the night sky as one year gives way to another — one we hope will be calm, safe, and happy for all.

Script by Damond Benningfield

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You don’t have to get too close to an exploding star for it to ruin your day. A recent study, for example, says that one or more exploding stars about 65 light-years from Earth could have caused a mass extinction.

The extinction took place about 360 million years ago. Some fish and other animals survived, but most organisms died off. Over the decades, scientists have proposed several possible causes, from huge volcanic eruptions to a collision with a comet or asteroid.

But the new study has another explanation: a supernova.

According to the study, a massive star — or maybe two of them — exploded when it reached the end of its life. That flooded Earth with radiation, destroying its protective ozone layer. Later, the supernova also bathed our planet in cosmic rays — heavy particles accelerated to near the speed of light. The combination created both a long decline in life — lasting a few hundred thousand years — and a shorter “pulse” of extinctions.

Other studies in recent years also suggested supernovae as engines of mass extinction. None of those ideas has been confirmed. But the new study offers a way to confirm it. Researchers say that debris from the explosion could be found in rock layers from the time of the die-off. In particular, even tiny amounts of plutonium or some other radioactive elements would be the “smoking gun” — confirmation that an exploding star zapped Earth almost 360 million years ago.

Script by Damond Benningfield

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Many New Year’s Eve celebrations include big displays of fireworks. Thanks to COVID-19, many of this year’s celebrations have been cancelled or scaled back. If our eyes were tuned to different wavelengths of light, though, we’d see big fireworks in the sky every night.

Some fireworks are at wavelengths that the human eye can perceive, but they’re just too faint to see. They include the exploding stars known as supernovae. Several of them pop off every day. And each one can outshine an entire galaxy of normal stars. None has exploded in our galaxy in four centuries. Those in other galaxies are so far away that you almost always need a telescope to see them.

And in fact, we don’t want a supernova to be too bright. An especially close one could cause big problems. We’ll have more about that tomorrow.

About once a day, orbiting satellites detect gamma-ray bursts. They’re extremely powerful explosions that “beam” gamma rays in our direction. Many of them are so bright that they’d be visible if our eyes could tune in to gamma rays.

The same thing applies to fast radio bursts. These outbursts last just a fraction of a second, but they can be extremely bright. So far, astronomers haven’t figured out their cause. They could be powered by collisions between the heavy cores of dead stars, but no one knows for sure.

So the universe produces dramatic fireworks — every night of the year.

Script by Damond Benningfield

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The Moon passes through one of the largest “asterisms” in the sky the next few nights: the Winter Circle. It contains several of the night sky’s brightest stars. But it’s so spread out that it’s hard to take in all at once.

An asterism is a pattern of stars that forms a distinctive shape or picture. It can be within a single constellation, or it can cross over constellation boundaries. The Winter Circle is in the latter category — it encompasses stars in six constellations. It spans about five times the width of your open hand held at arm’s length.

Tonight, the complete circle climbs into view by about 8 o’clock. Its hub is off to the lower right of the Moon: Betelgeuse, the orange shoulder of Orion the hunter. Orion’s brightest star, Rigel, forms part of the circle itself. It’s to the right of Betelgeuse, on the other side of Orion’s three-star belt.

If you go clockwise from Rigel, down near the horizon you’ll come to the Dog Star Sirius, the brightest star in all the night sky. Next up is Procyon, the little dog star, then Pollux and Castor, the twins of Gemini.

The circle sweeps upward from there to bright yellow-orange Capella, in Auriga the charioteer, and then over to Aldebaran, the eye of Taurus, the bull. Finally, it’s back down to Rigel to complete the circle.

It’s one of the grandest pictures in the night sky — a circle of bright stars that tonight forms a ring around the gibbous Moon.

Script by Damond Benningfield

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The Moon follows the follower across the sky tonight — the star Aldebaran, the eye of Taurus, the bull. Aldebaran is close to the right of the Moon as night falls, and below the Moon as they drop down the western sky in the wee hours of the morning.

Aldebaran is a red-giant star. It’s at the end of its life, so it’s puffed up to giant proportions. That’s made its surface much cooler than the Sun’s, so the star looks reddish orange. But it’s also much brighter than the Sun, so it’s an easy target.

The name “Aldebaran” comes from an Arabic phrase that means “the follower.” The name indicates that Aldebaran follows the Pleiades across the night sky — a tiny cluster of stars that forms the shoulder of the bull.

Aldebaran itself appears near another star cluster, the Hyades. The cluster forms the V-shaped outline of the bull’s face. Aldebaran is at one point of the V, so it represents the bull’s eye. But Aldebaran isn’t a member of the Hyades. It’s about 65 light-years away, which is only half as far as the Hyades.

Although Aldebaran is one of the brighter stars in the night sky, it won’t look its normal self tonight. Its closeness to the almost-full Moon will make it look a bit pale. And the star’s orange color will be washed out. Even so, Aldebaran will be easy to find — as the “follower” is followed by the brilliant Moon.

We’ll have more about the Moon, Aldebaran, and a circle of other bright stars tomorrow.

Script by Damond Benningfield

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A hundred years ago this month, Charles Abbot returned to the Smithsonian Observatory’s field station in the mountains west of Phoenix. Harqua Hala had been finished just months earlier. Yet as Abbot, the observatory’s director, climbed a five-mile trail to reach it, he saw that the station was a shamble. Some of the instruments had been destroyed. The water tank leaked. And one of the walls had buckled so severely that birds could fly through the cracks. “Devil appears to have claimed everything,” Abbot wrote.

During Harqua Hala’s five years of operations, the devils never went away. Weather, isolation, and the complexity of the work made life next to impossible.

Isolation was one of the site’s original selling points. The Smithsonian had operated a Sun-watching station near Los Angeles, but development spoiled the view. Abbot searched across the southwest for a better site, and picked Harqua Hala.

Observers there measured the Sun’s energy output, which Abbot hoped would lead to better weather forecasts. The work required exact timing and precise teamwork, plus long hours of calculations.

The weather added to their woes. Winds could reach gale force, and the summer monsoon brought heavy rains and vicious lightning. And high clouds and dust sometimes blocked the Sun, ruining a day’s work.

In 1925, Abbot decided the hazy skies were too much. So Harqua Hala was abandoned — left to the many “devils” of the Arizona desert.

Script by Damond Benningfield

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One of the most prominent constellations of summer transforms itself when the weather turns cold. It’s still the same pattern of stars, but because of the different viewing angle, it’s often seen as a different picture.

The constellation is Cygnus, the swan. During the summer months, it soars high across the evening sky. Its brightest stars form a pattern that looks like a graceful bird. Its long body lines up roughly parallel to the horizon, with its wings extending above and below the body.

By this time of year, though, Cygnus is in the western sky during the evening hours. Its bill points downward. And its wings are almost parallel to the horizon, as though the swan is plunging toward the ground. Seen at this angle, it more closely resembles the constellation’s nickname — the Northern Cross.

The star at the top of the cross represents the tail of the swan — blue-white Deneb. It’s one of the biggest, brightest, hottest stars in our region of the galaxy. Although there’s some wiggle room in the distance, the star probably is close to 1500 light-years away. That means the light we see from Deneb tonight has been crossing the Milky Way Galaxy for a millennium and a half — a long-distance trek from a star that anchors two star patterns.

Look for the swan in its alternate guise — the Northern Cross — standing well up in the western sky as darkness falls. It perches directly atop the horizon in mid-evening.

Script by Damond Benningfield

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The sky offers some beautiful holiday treats the next couple of nights: the gibbous Moon, some brilliant planets, and the bright constellations of winter.

Step outside before dinner to see Jupiter and Saturn in the southwest. The giant planets look like they’re about to touch each other. Jupiter is the brighter of the two, with Saturn a little lower in the sky. They’re inching away from each other, but will remain quite close through the end of the year.

At that same hour, the planet Mars shines like an orange star to the upper right of the Moon. Mars is among the half-dozen brightest objects in the night sky, so you can’t miss it. Mars and the Moon will remain close throughout the night, but will be farther apart by tomorrow night.

The constellations of winter take over after dinner. Orion, perhaps the most beautiful of all constellations, is in great view in the east and southeast by about 8 p.m. Look for its “belt” of three stars, with bright orange Betelgeuse to the left and blue-white Rigel to the right.

Follow the line of the belt toward the horizon to find Sirius, the Dog Star. It’s the brightest star in the entire night sky.

Other bright constellations encircle Orion, including Taurus, the bull, and Gemini, the twins.

And for those who start their Christmas Day early, the planet Venus is in the southeast during the dawn twilight. It’s the brilliant “morning star” — a beautiful treat for an early Christmas morn’.

Script by Damond Benningfield

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