StarDate

A star in a nearby galaxy appears to be going through a rare transition — from a monster to a super-monster. If that’s the case, it could be setting up for another transition: blasting itself to bits as a supernova.

The star is in the galaxy M33, in the constellation Triangulum, which is in the east-northeast at nightfall.

M33 is less than three million light-years away — a next-door neighbor. The galaxy is a beautiful spiral. We see it at a bit of an angle, so it looks like an octopus twirling in a cosmic ballet. The galaxy is home to perhaps 40 billion stars, and it’s giving birth to many more.

Some of the new stars belong to class “O” — the biggest, brightest, and heaviest class. Such stars burn for only a few million years before they explode.

Some of those stars undergo a brief transition before they blow up. They become Wolf-Rayet stars. They’re the hottest and brightest stars of all, but they explode quickly. Before they explode, they blow huge amounts of gas into space — enough to make several stars as massive as the Sun in less than a million years.

The winds enwrap the star in clouds of gas and dust, and that’s one way astronomers identify them. A recent study identified several chemical elements around a monster star in M33. One of those elements has only recently become visible, suggesting that the star is undergoing rapid change — from a monster into a super-monster.
 

Script by Damond Benningfield

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Until we started sending missions to the Moon, the concept of the lunar surface was one of jagged mountains and steep-walled canyons. That concept was molded mainly by the amazing artwork of Chesley Bonestell, which was featured in magazines and movies.

The reality is much different. The mountains and canyons are smooth and rounded — the result of billions of years of pounding by space rocks. Most of the rocks that hit the Moon are tiny — the size of pebbles or smaller. They slowly erode the mountains and churn the surface into a powdery soil.

But a few impacts are bigger — big enough to gouge visible impact craters.

A recent study looked at how often those larger impacts take place. Scientists compared pictures taken 42 years apart — the first by Apollo 15, the second by Lunar Reconnaissance Orbiter. The images covered about 10 square miles, near the Apollo 15 landing site.

The comparison showed about 320 new craters. The largest was 50 feet across. Some of the craters could be secondary — formed when the debris from a collision splashed out around the impact site. Even so, the study shows that the surface of the Moon continues to be resculpted — beaten into shape by a rain of space rocks.

The Moon has a prominent companion late tonight: Aldebaran, the bright orange heart of Taurus, the bull. The star is close to the lower right of the Moon as they climb into good view, by about 11 o’clock.
 

Script by Damond Benningfield

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It’s “take two” for a mission to a heavy-metal asteroid. The billion-dollar mission was supposed to launch in September of last year. But software problems forced NASA to cancel that attempt. The new launch window opens on Thursday, and continues through October 25th. If the craft gets off as planned, it’ll reach its target in 2029.

Psyche will orbit an asteroid of the same name. Most asteroids are made mostly of rock. But Psyche consists mainly of metals — primarily iron and nickel. It’s the largest metallic asteroid yet discovered — about 140 miles in diameter.

Most of the millions of asteroids that orbit the Sun probably are debris left over from the formation of the planets. But Psyche could be the remains of a much-larger body — something that was bigger than most asteroids, but not as big as a planet.

The original body could have been massive enough to form distinct layers. Iron and nickel fell to the middle, as they did in our own planet. So taking a look at Psyche could be like peeking into the heart of Earth.

We’ll get that peek because Psyche somehow lost its outer layers — perhaps in collisions with other asteroids. Only its core remained.

Psyche is about three times farther from the Sun than Earth is. The launch delay extended the travel time of Psyche the spacecraft. It’ll have to swing past Mars to get a gravitational “kick” — boosting it toward a heavy ball of metal in the asteroid belt.
 

Script by Damond Benningfield

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The Moon and the planet Jupiter stage a beautiful encounter tonight. They climb into view about 9 or 9:30. Jupiter looks like a brilliant star quite close to the Moon, which is just past full. They’ll move slightly farther apart by dawn, with Jupiter below the Moon.

Jupiter and the Moon are both passing through Aries, the ram. The Moon will complete that transit in a hurry. Tomorrow night, it’ll appear in Taurus, the next constellation over. And a few nights after that, it’ll move into Gemini.

That’s because the Moon is in a close orbit around Earth, so it moves quickly against the background of stars. It takes only about a month to complete a full circle through that background.

Jupiter, on the other hand, is orbiting the Sun, not Earth. And it’s a long way from the Sun — about half a billion miles. At that distance, it takes the giant planet almost 12 years to circle all the way through the starry background. So it’ll stay within the borders of Aries until the end of April. And once it exits, it won’t return to the ram until the spring of 2035.

During that interval, the Moon will make about 150 full turns across the sky — including many more close encounters with brilliant Jupiter.

Again, look for Jupiter and the bright gibbous Moon beginning in late evening, and continuing through the night — a beautiful pairing that repeats every month or so.

Tomorrow: a “psychic” mission of discovery.
 

Script by Damond Benningfield

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“Hot Jupiters” aren’t very friendly. Few of the giant planets have nearby companion planets. That could mean that the hot Jupiters have kicked other planets away.

Hot Jupiters were the first planets discovered in other star systems. They’re big, heavy balls of gas, like Jupiter, the giant of our own solar system. But while Jupiter is far from the Sun, hot Jupiters are quite close in, so they’re heated to hundreds or thousands of degrees.

Such planets can’t form that close to a star — it’s just too hot. They must have been born farther out, then moved inward. The question is whether that’s a gentle process, allowing the Jupiter to co-exist with other planets, or a more violent one that boots the other planets out of its way. And so far, the “violent” scenario has been the most likely, because astronomers have found few close companion planets.

But in a recent study, about one in eight hot Jupiters did have a nearby companion. Those Jupiter-like worlds must have migrated inward in the gentler process, sparing their sibling worlds. And warm Jupiters — those that are a little farther out — were more hospitable: about two-thirds had close companions. So there may be more than one way for a Jupiter to fall toward its parent star.

Our own Jupiter teams up with the Moon the next few nights. It looks like a brilliant star. It’s well to the lower left of the Moon tonight, but will huddle much closer tomorrow night.
 

Script by Damond Benningfield

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As the United States expanded westward in the late 1800s, it didn’t really know where everything was. The precise locations of towns and other landmarks were a little fuzzy, so maps could be off by quite a bit. To clear things up, the country turned to the stars. It dispatched surveying parties and established special observatories from Nebraska to Utah and Nevada. And one of those observatories took its first official look at the stars 150 years ago today.

The observatory was atop a hill near Ogden, Utah, a railroad junction with a population of about 2,000. The facility consisted of three rooms covered by a tin roof, including one room for recording the weather.

The observatory used a “transit” telescope to measure the positions of the stars. It then used telegraph signals to obtain the time from several cities whose exact positions were known. Comparing the star positions with the time allowed astronomers to accurately compute the location.

Ogden’s observatory operated through 1874, and took thousands of star sightings. In addition, several groups fanned out from Ogden to determine the positions of other locations.

The first stars observed from Ogden included several bright stars of Lyra, the harp, which is high overhead as night falls. Its leading light, Vega, is one of the brighter stars in all the night sky, so it’s easy to pick out — a bright light that helped illuminate the western United States.
 

Script by Damond Benningfield

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In the 14th century, the people of China were about to launch a revolt against the Yuan Dynasty. Legend says they coordinated the start of the revolution by passing messages inside mooncakes — pastries that are part of the celebration of mid-autumn. The messages said the rebellion would begin on the 15th day of the eighth month — the equivalent of the Harvest Moon in the western calendar.

The legend may or may not be true, but the Mid-Autumn Festival is still one of the most important events in the Chinese year — and it’s still tied to the Moon. And it’s getting underway now, because tonight is the night of the Harvest Moon — the full Moon closest to the autumnal equinox.

Many legends are associated with the Mid-Autumn Festival. Most are tied to the Moon goddess Chang’e. In one version, she became immortal by swallowing a pill that was intended for her husband. The angry husband chased her across the sky, but she escaped to the Moon — where she still lives today.

In fact, Chang’e has a bigger role in Chinese life than ever. It’s the name given to China’s lunar exploration program. Five missions have taken place so far — orbiters, landers, and rovers. The series has included the only craft to land on the far side of the Moon — the side we never see. It also includes the first mission to bring back samples of the Moon since the 1970s. The next Chang’e mission is set for launch in 2025.
 

Script by Damond Benningfield

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Astronomers and their telescopes get a lot of alerts — up to thousands per day. They report discoveries of some of the most impressive objects and events in the universe — and some of the most dangerous. The list includes many varieties of exploding stars, the mergers of heavy dead stars, nearby asteroids, and more. The alerts aren’t just for fun, though. They can trigger follow-up observations by astronomers and telescopes around the world.

The follow-up is needed to provide a complete picture of what’s going on. If astronomers discover a gamma-ray burst — one of the most powerful explosions in the universe — they want to see what’s happening with other “eyes” — telescopes that are sensitive to other wavelengths. That can tell them more about the blast and its aftermath, which helps them explain the explosion, its effects on its surroundings, and much more.

Many telescopes — both on the ground and in space — send alerts automatically. In some cases, astronomers look at the alerts and decide whether to turn their own telescopes toward the event. But some telescopes and networks of telescopes are designed to respond automatically.

A change in targets can disrupt scheduled observations, damaging other research. So systems have to be carefully designed — responding to the most important alerts, while leaving others for later.
 

Script by Damond Benningfield

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One of the moons of Saturn is like a water sprinkler that won’t turn off — it sprays everything around it. It provides the water and ice that make up one of Saturn’s rings, and squirts more water throughout the entire Saturn system.

Enceladus is about 300 miles in diameter. In 2005, the Cassini spacecraft discovered “geysers” of water shooting into space from the moon’s south pole. Later, Cassini even flew through the geysers, measuring their composition.

The water comes from a global ocean below the moon’s icy crust. “Vents” of hot water may shoot into the ocean from below, bringing along a variety of minerals. That appears to give Enceladus all the ingredients for life.

Late last year, James Webb Space Telescope took a look at Enceladus. It found that the geysers are still there, shooting out enough water to fill an Olympic pool in about two hours. They merge to form a “plume” that extends more than 6,000 miles from Enceladus. The moon orbits Saturn once every 33 hours, so the plume spreads out, forming a “doughnut” of ice around Saturn. The planet’s outermost ring lies within the doughnut, so it’s resupplied by the plume. But about two-thirds of the water spreads out, forming a thin, cold “fog” throughout Saturn’s rings.

Saturn is in great view tonight. It’s just a few degrees from the gibbous Moon — the width of a couple of fingers held at arm’s length. It looks like a bright star.
 

Script by Damond Benningfield

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During her days at Swarthmore College, Charlotte Moore found out two things: she was really good at mathematics, and she didn’t like teaching. Those realizations led to a long career in astronomy and physics.

Moore was born 125 years ago yesterday, in Pennsylvania. Her parents were teachers, and they encouraged her to get a good education. She earned a degree in math from Swarthmore. She worked as a substitute teacher to pay her way, but she didn’t like the experience.

Moore got a job at Princeton as a “computer” — she did the tedious calculations that today are done by electronic computers. She worked for Henry Norris Russell, a leading astronomer. They published many papers on binary stars and the chemistry of the stars.

In 1931, Moore moved to Mount Wilson Observatory in California. She studied the Sun — especially sunspots. She came up with the first good idea of the temperatures of the dark blotches, which are much cooler than the surrounding gas. While in California, she also earned her PhD, in astronomy.

Moore later returned to Princeton, where she worked with Norris. She married a fellow scientist, Bancroft Sitterley. And she developed reference tables for the chemical elements that are still in use today.

Charlotte Moore Sitterley finished her career at the National Bureau of Standards. Yet she continued to work for decades after retiring — all the way up to her death, at age 91.

Script by Damond Benningfield

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