StarDate

A small star with a planetary companion appears to be making a high-speed exit from the center of the Milky Way – perhaps fast enough to escape the galaxy entirely.

The system is more than 24,000 light-years away, in Sagittarius. It appears to contain a red-dwarf star – a cool, faint ember about 20 percent the mass of the Sun. It’s accompanied by a “super-Neptune” – a planet about 30 times the mass of Earth. They’re separated by less than the distance from Earth to the Sun.

What makes the system especially interesting is its high speed – at least 1.2 million miles per hour. That’s not fast enough to leave the Milky Way behind. But it could be moving a good bit faster.

The system might have started as a member of a binary – two stars bound by gravity. The stars passed too close to the monster black hole in the galaxy’s heart. The black hole grabbed the other star, and gave the escapee a giant kick. On the other hand, the kick could have come from an encounter with a smaller black hole in the Milky Way’s crowded center.

How the star maintained its grip on the planet is a key question. But the planet must have been in a tight orbit to avoid being yanked away.

Researchers were scheduled to take some follow-up observations this month. That might reveal whether the system really is a star and planet on a high-speed ride through the galaxy.

We’ll talk about another possible escapee tomorrow.

Script by Damond Benningfield

The supermassive black hole at the heart of the Milky Way is never quiet – it’s constantly popping off.

The black hole is more than four million times the mass of the Sun. It grabs passing gas clouds, asteroids, and other objects. It also sponges up gas from the “winds” produced by nearby stars. This forms a swirling disk around the black hole. As material spirals inward, it gets extremely hot.

Astronomers watched the black hole with James Webb Space Telescope. They found that it produces several bright outbursts every day, with each one lasting an hour or longer. Between these outbursts there were fainter flares that usually lasted less than a minute.

The flares may have different causes.

Shorter flares may be caused by turbulence in the disk, which squeezes and heats pockets of gas. Particles bounce around inside these pockets, heating up and producing outbursts of energy. The longer flares may explode when magnetic fields twist together, then snap. That produces big outbursts of particles and energy like the giant flares on the Sun.

The astronomers hope to take an even longer look at the system, helping them learn more about the constant flare-ups from the Milky Way’s monster black hole.

The black hole is in Sagittarius. The constellation is in the south on summer evenings, and forms the outline of a teapot. The black hole is immersed in the “steam” above the spout – 26,000 light-years away.

Script by Damond Benningfield

Sagittarius marks the center of our home galaxy, the Milky Way. So the constellation is packed with stars, star clouds, and star clusters. But one of the clusters doesn’t belong to the Milky Way at all – at least not yet. It’s in a small, puffy galaxy on the far edge of the Milky Way’s disk.

Messier 54 is a globular cluster – a ball-shaped region about 150 light-years across, packed with hundreds of thousands of stars.

Native globulars are among the Milky Way’s oldest residents – they were born with the galaxy itself. But a few of the clusters were born in other galaxies, then absorbed when their home galaxies were absorbed by the Milky Way.

For a long time, astronomers thought that M54 was a charter member of the Milky Way – one of its early globular clusters. A couple of decades ago, though, they found that it’s near the center of a newly discovered galaxy, the Sagittarius Dwarf. That puts it outside the Milky Way’s disk. But the Milky Way is pulling the smaller galaxy in. Eventually, it will incorporate all of the galaxy’s stars. So M54 will become a member of the Milky Way – one of its newest residents – and one of its oldest.

Sagittarius scoots low across the south on summer nights. It looks like the outline of a teapot. M54 is at the lower left corner of the teapot, but you need a telescope to see it.

Script by Damond Benningfield

Mars won’t exactly roll out the red carpet for human explorers. In fact, the Red Planet could be deadly. It’s bitterly cold, the air is too thin to breathe, there’s no ozone layer to block the Sun’s ultraviolet rays, and there’s no magnetic field to deflect solar storms.

And if that’s not enough, there’s one more potential hazard: dust. A recent study said the dust could damage lungs and other organs and cause nasty diseases.

Dust covers much of the planet, giving Mars its orange color. It’s easily lofted by the wind, and dust storms can blanket much or all of the planet.

Researchers studied the dust, along with problems that Apollo astronauts experienced with Moon dust. They found that the Mars dust grains are too small to be filtered out by the lungs. Instead, they’d enter a person’s bloodstream. Not only are the grains abrasive, but the dust contains high levels of some nasty compounds. So the dust could cause everything from thyroid problems to a condition similar to black-lung disease.

Some ailments could be treated on Mars. But any serious problems might require help from Earth – a journey of months. So Mars travelers will need good air filters, self-cleaning spacesuits, and other methods to protect them from the deadly sands of Mars.

Mars stands close to the crescent Moon as darkness falls this evening. It looks like a fairly bright star – a hazardous destination for human explorers.

Script by Damond Benningfield

Astronomers generally don’t play many official practical jokes. But an Italian astronomer played one more than two centuries ago. And the joke is still there for everyone to see. It’s in Delphinus, the dolphin.

The constellation is small and fairly dim. But five of its stars form an outline that really does resemble a dolphin, making it easy to find. It’s a third of the way up the eastern sky at nightfall, with the dolphin’s tail on the right and its snout on the left.

The brightest members of the outline are Beta and Alpha Delphini. Beta is a binary – two stars bound by their mutual gravitational pull. Both are bigger, brighter, and heavier than the Sun. Alpha consists of three stars. All of them are more impressive than the Sun, with the main star almost four times the mass of the Sun.

The stars also have proper names. Beta is known as Rotanev; Alpha is called Sualocin. And that’s where the joke comes in.

The names first appeared in 1814, in an atlas published by the director of the Palermo Observatory. The names caught on, but their origin was a mystery. It was solved by a British astronomer 45 years later.

He realized that the observatory’s assistant director at the time was Niccolo Cacciatori. In English, the name would be Nicholas Hunter; in Latin, Nicolaus Venator. Spell the Latin names backwards, and you come up with Sualocin and Rotanev – a little joke among the stars of the dolphin.

Script by Damond Benningfield

Zeta Tauri is the kind of star that few of us really notice. It’s at the tip of one of the horns of Taurus, the bull. But it shines at only third magnitude. That’s no problem under dark skies, but tough to see from a light-polluted city. It’ll be much easier to find before dawn tomorrow, though, because it’ll stand just a whisker from Venus, the brilliant “morning star.”

Zeta Tauri is actually two stars, not one. They’re separated by a bit more than the distance from Earth to the Sun. But at the system’s distance of about 440 light-years from Earth, it’s impossible to see them as individual stars, even with the largest of telescopes. In fact, it’s tough to even learn the nature of the two stars.

One of the stars is easy to figure out. It’s about 11 times the mass of the Sun, five times wider than the Sun, and thousands of times brighter. But its companion isn’t fully understood. It may be a white dwarf – a stellar corpse as heavy as the Sun.

The main star is blowing a strong wind of gas into space. That’s formed a cloud around the star. The white dwarf may pull in some of that material. As it piles up on the white dwarf it gets much hotter, making the system a strong source of X-rays.

In the next few million years, the heavier star of Zeta Tauri is likely to explode as a supernova. That’ll make it impossible to overlook this currently meager star.

Script by Damond Benningfield

Water, water everywhere, nor any drop to drink.

The line from “The Rime of the Ancient Mariner” is true not only on Earth, but across the solar system. Water is everywhere. But it’s not in a form you could drink. It’s in the clouds of the giant outer planets, frozen in the surfaces and ice caps of planets and moons, or buried far below their surfaces.

One example is Pluto. The dwarf planet is billions of miles from the Sun, so its surface is frozen. But there’s evidence that liquid water lurks far below. In fact, there could be a global ocean up to a hundred miles deep.

One bit of evidence is a feature called Sputnik Planitia – a fairly smooth plain about 600 miles across. It’s almost pure white. And there are no impact craters, suggesting that the surface is young.

Among its features are floating blocks of frozen gases. They resemble slabs of ice in the polar regions of Earth. That suggests they could be floating atop liquid water. Plumes of water flow upward, freezing and pushing older ice outward. In fact, the feature might have formed when a big asteroid slammed into Pluto. It vaporized the surface, exposing the ocean below. The water quickly froze, forming the plain we see today.

Pluto lines up opposite the Sun this week. It’s in view all night, and shines brightest for the whole year.

Script by Damond Benningfield

The east coast of Florida first heard the roar of a rocket heading toward space 75 years ago today. It failed. But it set the stage for thousands more launches – payloads intended for Earth orbit, the Moon, and targets throughout the solar system.

The military had been conducting test flights from White Sands, New Mexico. But it was limited by the land-locked site. So it turned to a piece of scrubland known as Cape Canaveral.

The site was chosen because it was isolated, it offered a moderate climate, and it was close to the equator, so it gave east-bound rockets an extra kick.

Most important, it offered tens of thousands of square miles of open ocean to catch falling rockets. So workers carved out some space and built several launch pads.

And on July 24th of 1950, they put one of them to work, launching a rocket called Bumper 8. The first stage was a V-2 captured from Germany at the end of World War II. The second stage was a small American-built rocket.

As often happened in the early days, something went wrong. The rocket followed the wrong path, causing the second stage to fail. A second Bumper launch, nine days later, fared a bit better, but still didn’t achieve all of its goals.

Today, Cape Canaveral and the adjoining Kennedy Space Center are busier than ever. Last year, they hosted a record 93 launches – adding to the tally of a 75-year-old spaceport.

Script by Damond Benningfield

A big storm on the Sun in May of 2024 caused big trouble for satellites. And they could face even bigger troubles in the coming decades.

The storm was an especially powerful outburst of energy and particles. When the storm hit Earth, it heated the outer atmosphere, causing it to expand. That increased the drag on satellites in low orbit, causing them to lose altitude. A study put the average drop at about 600 feet per day – the length of two football fields.

The satellites had to fire their thrusters to stay where they belonged. The study said that thousands of satellites had to execute those maneuvers – up to 5,000 per day. It was impossible to calculate all those maneuvers at once, so the risk of collisions went way up.

No impacts were reported. But the number of satellites continues to skyrocket. And another study forecasts that the Sun should get even stormier over the next 40 years or so.

The Sun goes through an 11-year cycle of magnetic activity. But there’s also a cycle of cycles. The average level of activity goes down for four or five cycles, then goes up for the next four or five. The study says we’ve reached the bottom of that “super” cycle, and should be on the way up. That means more big storms from the Sun, and more maneuvering by satellites – increasing the risk of collisions in low Earth orbit.

Script by Damond Benningfield

Jupiter’s Great Red Spot is one of the most intriguing features in the solar system. It’s a storm that’s big enough to swallow Earth – but getting smaller.

Winds at its perimeter blow much faster than any hurricane on Earth. And it has a bright reddish orange color. Despite a century and a half of study, though, it’s still mysterious. Scientists don’t know why it’s red, why it’s getting smaller, or how it fired up in the first place.

They do know that the storm drifts westward around the planet. And a recent study found that it “inches” along like a garden slug.

Scientists monitored the storm for three months with Hubble Space Telescope. They already knew that the Great Red Spot goes through a 90-day cycle. But this was the first time they plotted the changes in detail.

The images revealed that the spot stretches and squeezes as it moves. When it’s moving slowest, it’s stretched out. When it’s moving fastest, it’s more compressed, so it’s a little rounder. The storm’s width varies by about a hundred miles, and its height by a bit more.

The spot’s average width is more than 8,000 miles. That’s only a third the size when it was first seen. No one knows whether it will continue to shrink – and eventually disappear.

Look for Jupiter close to the right of the Moon in tomorrow’s dawn twilight. It looks like a bright star. But it’s so low that you need a clear horizon to spot it.

Script by Damond Benningfield