StarDate

For three centuries, an insect buzzed around the backside of Aries. But the ram got rid of the pest a century ago, claiming the stars as its own.

The buzzer was created in 1612, by Dutch astronomer Petrus Plancius. He took some faint stars from an empty region near Aries. He named his new constellation Apis — Latin for “bee.”

But there was already a celestial bee. So in 1687, German astronomer Johannes Hevelius renamed Apis. He called it Musca — the fly. And in 1822, it was adjusted to Musca Borealis, the northern fly, because there was already a fly in the southern hemisphere.

A century later, though, astronomers replotted the skies. They got rid of several constellations and gave their stars to others. Musca Borealis was one of the victims. Its stars were incorporated into the ram.

The northern fly was never much to look at. Its brightest star is too faint to see from a modern city. It’s known as 41 Arietis. It’s actually a triple system — three stars bound by their mutual gravity. Two stars form a tight pair, with a third star a good distance away from them. The leading member of the system is bigger than the Sun. It’s also about 160 times brighter, which is why the system is visible at all from its distance of 166 light-years.

The ghost of the northern fly flutters near the ram, which is half way up the eastern sky at nightfall. You need dark skies to see any of the fly’s faint stars.

Script by Damond Benningfield

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Cosmic rays are handy things for scientists. They tell us about some of the most powerful and dramatic events in the universe. They reveal details about the structure of matter. And for British scientist Patrick Blackett, they led to the 1948 Nobel Prize in Physics.

Blackett was born 125 years ago today. He enrolled in a naval academy at age 13. He served in the Royal Navy during World War I and saw combat in a couple of campaigns. After the war, he decided to study physics. In particular, he studied the newly discovered particles known as cosmic rays.

Today, we know they come from exploding stars and other powerful events far outside our galaxy. At the time, however, they were a complete mystery. Blackett and his colleagues examined the nature of the high-energy particles and how they react with other matter. That provided details on how atoms and their particles are put together. It also led to experiments in which he transformed oxygen atoms to nitrogen — the first successful “transmutation” in history.

During World War II, Blackett worked on defenses against German U-boats and on better anti-aircraft systems. After that, he developed a new scientific interest: the magnetic fields of Earth and the Sun. His work helped confirm that Earth’s continents move around.

Blackett died in 1974 — a man who helped us learn about our planet, our universe, and the tiniest particles of matter.

Script by Damond Benningfield

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Once every few weeks, the star system Z Camelopardalis pops off. It flares to about 50 times its normal brightness, then slowly fades. But at least once in the last couple of thousand years, it probably flared thousands of times brighter than its normal outbursts — like the difference between a flashlight and a searchlight. And today, astronomers can still see the residue of that blast.

The system is in Camelopardalis, the giraffe. The constellation is about half way up the north-northeastern sky at nightfall.

Z Cam consists of two stars. One is a white dwarf — the small, hot corpse of a once-normal star. Its companion is much like the Sun. The stars are so close together that the white dwarf “steals” some of the companion’s gas. The gas forms a swirling hot disk around the white dwarf. Every few weeks, the disk falls onto the white dwarf, creating an outburst.

But a few years back, astronomers discovered a shell of gas and dust around Z Cam. It’s several light-years wide, suggesting it’s been expanding into space for a long time.

The shell probably was produced in a much more powerful outburst. Lots of gas from the companion built up on the white dwarf. This material got so hot that it triggered a nuclear explosion, blasting the layer of gas into space.

The blast was so bright that it might have been visible from Earth. In fact, Chinese astronomers might have recorded it — 2100 years ago.

Script by Damond Benningfield

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An up-and-down meteor shower will be at its best the next few nights. On the downside, the Moon will be in the middle of the action. On the upside, the shower could produce a bonus on Friday night.

The Leonid meteor shower is the spawn of Comet Tempel-Tuttle. As the comet orbits the Sun, it sheds grains of dirt and rock. They form a wide trail behind the comet. Earth flies through that trail every November. Bits of comet dust ram into the atmosphere at more than 150,000 miles per hour. They quickly vaporize, forming the glowing streaks of light known as meteors or shooting stars.

Every 33 years or so, we fly through a denser clump of comet dust, creating a meteor storm — thousands of meteors per hour. Unfortunately, that’s not happening this year. Instead, we’ll see perhaps a dozen meteors per hour at the shower’s usual peak, tomorrow night.

A couple of meteor experts say we could encounter a denser part of the comet trail around midnight on Friday, producing a few dozen to a couple of hundred meteors per hour.

Unfortunately, the Moon is in the middle of the action. The focal point of the shower is in Leo. Tonight, the Moon is close to the lion’s brightest star, Regulus. Meteors can appear anywhere in the sky, but the Moon makes it harder to spot them. By Friday night, the Moon will rise late enough to provide a short window for watching the meteors, with peak hours from about midnight until 2 or 3 a.m.

Script by Damond Benningfield

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The last-quarter Moon moves toward a familiar companion late tonight: Regulus, the “heart” of Leo, the lion. The bright star rises below the Moon, and is in good view by 1 o’clock. The Moon will slide closer to Regulus during the night.

Regulus sits almost directly on the ecliptic — the Sun’s path across the sky. The Moon stays close to the ecliptic as well. That means the Moon can pass in front of Regulus, blocking the star from view. Such an event is called an occultation, from a Latin word that means “to hide.”

Occultations happen only when the Moon is crossing the ecliptic at the same time it’s passing Regulus. Thanks to that geometry, occultations come in bunches that are about eight or nine years apart. The last bunch wound up in July of 2017. The next one will begin in July 2025 and end a year and a half later.

The Moon isn’t the only body than can occult the star — so can the planets. Because the planets are much smaller targets in our sky, though, such events are quite rare. The last one came in 1959, with Venus crossing in front of Regulus. And our neighbor planet will repeat the performance in 2044.

For now, though, nothing is blocking our view of the lion’s magnificent heart. Watch it trail the Moon across the sky beginning after midnight. And if you miss it tonight, they’ll pair up again tomorrow night — but with the Moon following the star.

Tomorrow: the lion breathes fire.

Script by Damond Benningfield

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The asteroid that killed the dinosaurs might have had some help. A crater discovered off the coast of Africa formed at about the same time as the one gouged by the dinosaur killer. That suggests they could have been companions — perhaps formed by pieces of a larger asteroid.

Much of the life on Earth died when a miles-wide space rock slammed into our planet 66 million years ago. The impact formed a crater in the Gulf of Mexico. Known as Chicxulub, it’s more than a hundred miles wide. Debris that was blasted into the air blotted out the Sun and caused acid rain around the globe.

A couple of years ago, researchers were studying the floor of the Atlantic Ocean when they discovered a new crater near Africa. It’s only five or six miles wide. The asteroid that created it was about a quarter of a mile in diameter. The impact would have produced a massive fireball, vaporized rocks and ocean water, and triggered tsunamis.

The crater formed at about the same time as Chicxulub. So the asteroids that created them could have been companions — perhaps fragments of a single asteroid that broke apart when it reached Earth. Or perhaps the parent asteroid broke apart much earlier, with the two pieces hitting Earth at different times. Or perhaps it’s just a coincidence, and the two asteroids were unrelated.

Scientists plan to drill into the crater to learn exactly when it formed — telling us whether a dinosaur killer had some help.

Script by Damond Benningfield

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Many of the myths of ancient Greece sound like they were written for Hollywood. There’s beauty, mystery, and treachery, with enough nasty monsters to occupy hordes of computer animators. One of the nastiest is Cetus, the sea monster, which crawls across the southern sky on November evenings.

His story begins with Cassiopeia, the queen of Ethiopia. She was beautiful but vain — she bragged that she was the most beautiful of all. That didn’t sit well with the sea nymphs, who were also great beauties. They asked their father, Poseidon, to punish Cassiopeia for her boasting. He did, by sending Cetus to destroy the kingdom.

Cetus often is depicted as having the head and front legs of a land creature, but the body of a sea serpent. And he was huge — big enough to flatten villages.

The oracles told King Cepheus that the only way to save his kingdom was to sacrifice his daughter, Andromeda. So he ordered her chained at the shoreline.

Just as the monster approached, though, Perseus the hero came to the rescue. Depending on which version of the tale you read, he either hacked the monster up or turned him to stone with the head of Medusa, another nasty creature. Either way, Andromeda was saved, and Cetus was banished to the stars.

The constellation is climbing into view in the southeast at nightfall, and is in full view an hour or so later. But it has few bright stars, so you need dark skies to see this giant sea monster.

Script by Damond Benningfield

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Cassiopeia the queen stands high in the northeast at nightfall. Some of her stars form a giant letter M or W. 450 years ago this week, a brilliant new star appeared near the center point of that letter.

Today, it’s known as Tycho’s Supernova, for Tycho Brahe, who published an extensive study of it. But it might also be called Hamlet’s Supernova. A study a few years ago suggested the star might have inspired William Shakespeare to write the famous play.

The star appeared in 1572, when Shakespeare was eight years old. It became as bright as Venus. It flared into view when a “dead” star stole gas from a companion star, causing the dead star to explode.

At the time, the heavens were considered unchanging. A bright “new” star popping into view shook up that concept. The idea that Earth was the center of the universe also was changing, creating a time of uncertainty. And change and uncertainty are a theme in Hamlet, which was written around 1600.

A few years ago, a team led by Don Olson at Texas State University suggested the play was inspired by the supernova. Dialogue suggests it was set in November, and references a star that “burns” near the spot of the supernova. The play is set near Tycho’s observatory. And astronomy played a role in other Shakespeare plays.

There’s no “smoking gun” to confirm the idea. But it suggests that one of history’s great works of art could have been inspired by a great work of nature.

Script by Damond Benningfield

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Tycho Brahe was one of the greatest observers of the night sky. In the era before telescopes, he compiled some of the most accurate star catalogs in history. It didn’t take a lot of talent for him to notice a bright new star in Cassiopeia, though. Tycho logged it 450 years ago tonight. He studied the star extensively, so today it’s known as Tycho’s Supernova.

At the time, the heavens were considered not only unchanging, but unchangeable. A new star suddenly flaring to life didn’t fit that model at all. It helped create a revolution in our understanding of the universe.

It took centuries for astronomers to figure out what had created the new star: a supernova. A “dead” star known as a white dwarf had pulled gas off the surface of a companion star. Eventually, so much gas piled up on the white dwarf that it caused a runaway nuclear explosion. That blasted the white dwarf to cosmic dust.

The supernova was extremely bright. It eventually got as bright as Venus, the brightest object in the night sky after the Moon. And it remained visible for a year and a half.

Today, the debris from that explosion forms a bubble of gas and dust. It’s expanding at two or three percent of the speed of light.

The bubble is too faint to see without a telescope. But you can easily spot its location. It’s close to the left of the center point of the “W” that outlines Cassiopeia, high in the northeast at nightfall.

Script by Damond Benningfield

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A couple of bright orange dots accompany the gibbous Moon across the sky tonight: the planet Mars and the star Aldebaran. Mars is the brighter of the two, and rises close to the lower left of the Moon. Aldebaran is farther to the right of the Moon. They’re all in good view by about 8 o’clock.

Mars and Aldebaran appear orange for different reasons. Mars is “rusty” — it’s covered by dust that contains a lot of iron, which has a dark orange color. Aldebaran is orange because its surface is fairly cool, and cooler gas looks redder than hotter gas.

Mars is about eight times brighter than Aldebaran right now. Aldebaran’s brightness doesn’t really change. The star is so far away that any changes in its distance are insignificant.

But Mars is in our own solar system. It’s the next planet out from the Sun. So over a couple of years, its distance from Earth varies by a wide margin — from a maximum of almost 250 million miles to a minimum of less than 40 million.

Now, Earth and Mars are heading toward one of those close encounters. On December 1st, they’ll pass about 50 million miles apart. And as Mars gets closer, it gets brighter. At its brightest, the only objects in view in the night sky that will outshine it will be the Moon and the planet Jupiter.

Mars and the Moon will move closer to each other during the night, and will appear to almost touch each other at dawn. They’ll remain close tomorrow night.

Script by Damond Benningfield

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