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Sculptor Nov 13, 2025

Nicolas-Louis de Lacaille had a great imagination. In the 1750s, the French astronomer mapped more than 10,000 stars from the southern tip of Africa. Lacaille used those stars to create 14 new constellations.

One of them is Sculptor. Lacaille originally called it the Sculptor’s Studio. It depicted a carved head atop a stool, plus a hammer and chisel and a block of granite.

But all of that takes a lot of imagination to see. All of the constellation’s stars are so faint that Sculptor is invisible from light-polluted cities and suburbs.

Sculptor is important to astronomers, though, because many galaxies lie within its borders. The closest of them is the Sculptor Dwarf. It’s just 300,000 light-years away, and it orbits our home galaxy, the Milky Way.

The galaxy contains only 30 million stars or so. But most of them are ancient – far older than most of the stars in the Milky Way. That means the Sculptor Dwarf may be a remnant from the early universe – like the many building blocks that came together to form the Milky Way. So studying the galaxy can tell us much more about the early universe, and the history of our own galaxy.

From most of the United States, Sculptor is low in the southeast in early evening,. But you need a dark sky to make out any of its stars – and a good imagination to “see” a pattern in them.

We’ll have more about Sculptor tomorrow.

Script by Damond Benningfield

Moon and Regulus Nov 12, 2025

The brightness of any star that’s in the prime phase of life is controlled by the star’s mass: Heavy stars are brighter than lightweight stars. But it’s not a simple one-to-one kind of relationship. A star that’s twice the mass of the Sun isn’t twice as bright – it’s more than 15 times as bright.

That’s because gravity squeezes the core of a heavier star more tightly. That increases the core’s temperature, which revs up the rate of nuclear reactions. That produces more energy, which makes its way to the surface and shines out into space.

Regulus illustrates the point. The heart of the lion consists of four stars, three of which are in the prime of life.

The star we see as Regulus – Regulus A – is a little more than four times the mass of the Sun, yet it radiates about 340 times more energy. Much of that energy is in the ultraviolet, which we can’t see. But even at visible wavelengths, it’s about 150 times the Sun’s brightness.

Regulus A has a couple of distant companions. Regulus B is about 80 percent the mass of the Sun, but only a third of the Sun’s total brightness. And Regulus C is even more dramatic: a third of the Sun’s mass, but just two percent its brightness – a cool, faint ember in the heart of the lion.

Look for Regulus standing close above the Moon as they climb into good view around 1:30 or 2 in the morning. The star will be a little farther from the Moon at dawn.

Script by Damond Benningfield

Vesto Slipher Nov 11, 2025

Edwin Hubble gets the credit for discovering that the universe is expanding. But that finding was made possible by work done by Vesto Slipher. He was the first to measure the motions of distant galaxies – the key to Hubble’s discovery.

Slipher was born 150 years ago today, in Mulberry, Indiana. He worked on the family farm, and developed an interest in astronomy. A college professor helped him get a job as an assistant at Lowell Observatory in Arizona, where he worked for the next five decades.

Slipher studied what were called “spiral nebulae.” It wasn’t certain whether these pinwheels were motes of matter in the Milky Way, or “island universes” of stars outside the Milky Way.

Slipher used a technique that splits an object’s light into its individual wavelengths. The object’s motion shifts those wavelengths. Objects that are moving away from us are shifted to longer, redder wavelengths.

Slipher found that most of the spirals were moving away from us in a hurry. He suggested the objects were far outside the Milky Way. But he couldn’t prove it because he had no way to measure the distances.

Hubble did measure the distances, proving that the spirals are separate galaxies. He then combined Slipher’s observations with his own to show that the farther a galaxy, the faster it was moving. Later, astronomers concluded that the universe is expanding – a finding made possible in large part by Vesto Slipher.

Script by Damond Benningfield

Makahiki Nov 10, 2025

There’s nothing in the night sky quite like the Pleiades. The star cluster forms a tiny dipper. Depending on sky conditions and the viewer’s eyesight, anywhere from a half dozen to a dozen stars or more are visible to the naked eye.

Its unique visage has made the Pleiades one of the most important sky objects in many cultures. The people of the Andes timed the start of the harvest season to its first appearance in the dawn sky. The Aztec year began at about the same time.

In Hawaii, the Pleiades was known as Makali’i. And the year began when Makali’i first appeared in the evening twilight – the middle of November. The year, the new year, and a festival period shared a name: Makahiki.

The customs varied from island to island. But they had a lot in common. The celebration lasted for several months. Warfare and most work were banned. Instead, people danced, feasted, played sports, and reconnected with family and friends. And they made offerings to Lono, a god of agriculture, music, and peace.

The Pleiades is just climbing into the evening twilight, in the east-northeast, across Hawaii and most of the rest of the country. In some Hawaiian traditions, Makahiki doesn’t begin until the first appearance of the crescent Moon in the west after the Pleiades returns. That’s coming up on the 21st – the start of the new year and the celebration that honors it. Hau’oli makahiki hou! – Happy New Year!

Script by Damond Benningfield

Moon and Companions Nov 09, 2025

The Moon shoots the gap between some bright companions tonight: the planet Jupiter and the star Pollux, the brighter “twin” of Gemini. They climb into good view by about 10:30 or 11, and stand high overhead at dawn tomorrow.

Jupiter is the largest planet in the solar system, and it has the most turbulent atmosphere. Hurricane-like storms as big as continents twirl across it.

Thunderstorms can produce lightning bolts far more powerful than any on Earth, as recorded by a passing spacecraft. And the storms might produce their own giant hailstones: “mushballs” as big as softballs.

The idea was first proposed in 2020. And a study published earlier this year supports it. The study used observations by the Juno spacecraft, which is orbiting Jupiter, along with Hubble Space Telescope and a radio telescope on Earth

The study says the mushballs may begin as droplets of frozen water far below the cloud deck. They get caught in updrafts that howl at 200 miles an hour.

They’re carried to the tops of the clouds, which can be tens of miles thick. Along the way, the ice mixes with ammonia, forming a slushy liquid. When the balls get heavy enough, they begin to drop. As they descend, they’re coated with fresh ice, giving them a hard shell around a slushy middle – mushballs.

The mushballs plunge hundreds of miles below the clouds, where they vaporize – “mushing” into the depths of the giant planet.

Script by Damond Benningfield

Cosmic Rays Nov 08, 2025

In the early 20th century, scientists discovered a mysterious new type of radiation. The higher they went, the stronger it became. They realized that it came from beyond Earth. And 100 years ago tomorrow, it got a name: cosmic rays.

Nobel Prize winner Robert Millikan had become fascinated by the rays from outer space in the early ’20s. He coined the name “cosmic rays” in a paper about them, which he presented to a meeting on November 9th, 1925.

Millikan thought the rays were a form of energy produced by matter that was being born in the space between the stars. Others disagreed, especially Arthur Compton – a future Nobel Prize winner himself. He argued they were subatomic particles racing through the universe at almost the speed of light.

Compton was right. Cosmic rays are electrons, protons, or the nuclei of atoms. Most of the ones that hit Earth are produced by the Sun. But others come from far beyond our own solar system – and even from beyond our galaxy. The most energetic ones come from exploding stars, or from the violent regions around black holes.

Most of these distant cosmic rays are blocked by the Sun or by Earth’s magnetic field. But a few enter the atmosphere. They strike atoms and molecules in the air, creating “showers” of other particles. If a shower occurs above the right kind of clouds, it can create lightning – a terrestrial light show with an extra-terrestrial origin.

Script by Damond Benningfield

Lunar Excursion Nov 07, 2025

Nothing can survive the brutal conditions on the surface of the Moon. But a story that debuted 125 years ago depicted a vast civilization below the surface – a society of insects.

First Men in the Moon was written by H.G. Wells. It was published over several months in two magazines – “The Cosmopolitan” in the United States, and “The Strand” in Britain. The first installment appeared in November of 1900.

In the story, a man named Bedford befriends a scientist named Cavor who’s invented “cavorite” – a substance that nullifies gravity. He builds a ship and covers it with shutters that are coated in the stuff. Opening and closing the shutters allows the ship to move through space.

The two men travel to the Moon, where they’re taken underground by the Selenites. Bedford escapes. Thinking Cavor is dead, he returns to Earth alone. But two years later, Cavor starts beaming messages to Earth. He describes the Moon and its inhabitants in detail. After he tells the Selenite’s leader of Earth’s war-like tendencies, though, he’s cut off – and never heard from again.

First Men in the Moon was a hit. It influenced scientists and other fiction writers alike for decades, inspiring more stories, plus efforts to reach the Moon – a world populated only in the imagination.

The Moon climbs into good view by about 8 o’clock tonight. Elnath – the second-brightest star of Taurus – is quite close to the Moon’s upper left.

Script by Damond Benningfield

Biggest Black Hole Nov 06, 2025

The black hole at the heart of the Milky Way is like the monster lurking under your bed. It’s four million times the mass of the Sun, and about 15 million miles across – just waiting to gobble up anything that gets too close.

But compared to the black holes in many other galaxies, the one in the Milky Way is less like a monster and more like a dust bunny. The largest ones yet seen are thousands of times bigger. They’re known as ultra-massive black holes. Informally, they’re also called SLABs – stupendously large black holes.

Just which one is the biggest is uncertain – it’s hard to measure the mass of something that might be billions of light-years away. A recent candidate is in a structure known as the Cosmic Horseshoe. The gravity of a stupendously large galaxy “warps” the view of a galaxy behind it, creating what looks like a big, blue horseshoe.

In a recent study, astronomers combined a couple of techniques to measure the mass of the black hole in the foreground galaxy: 36 billion times the mass of the Sun. Researchers say the combo makes the measurement the most accurate for any candidate for the “biggest black hole” honors.

But other black holes could be bigger. The biggest candidate is known as Phoenix A. It could be up to about 25 thousand times the mass of the Milky Way’s black hole. But that number is highly uncertain. So the search for the biggest black hole continues.

Script by Damond Benningfield

Oldest Black Hole Nov 05, 2025

A Little Red Dot might have a big black hole in its heart. And that’s a bit of a challenge to explain.

Little Red Dots are galaxies from the first 1.5 billion years of the universe. The name comes from their appearance – they’re small and red, but they’re especially bright. They don’t appear to have enough stars to make them so bright. So a good bit of their “shininess” could come from giant black holes that are devouring material around them. As they tumble inward, the hot gas, dust, and stars produce enormous amounts of energy.

Even so, the black hole in one Little Red Dot is a bit of a puzzler.

Led by astronomers at the University of Texas at Austin, a team looked at CAPERS-LRD-z9 with Webb Space Telescope. By measuring the speed of material orbiting the center of the galaxy, the team determined that the black hole is up to 300 million times the mass of the Sun.

And that’s where the challenge comes in. The galaxy is so far away that we see it as it looked when the universe was just 500 million years old – three percent of its current age. That makes the black hole the most-distant yet seen. But theories of how such monster black holes form say that half a billion years probably isn’t long enough to make one that big. So theorists have a lot of work to do to explain the giant black hole at the center of a Little Red Dot.

More about black holes tomorrow.

Script by Damond Benningfield

Hunter’s Moon Nov 04, 2025

With the autumn harvest safely stowed away, many people in bygone centuries turned their attention to hunting. And just as the Harvest Moon helped them bring in the crops, the Hunter’s Moon helped them find game. The moonlight made it easier to track animals through the empty fields and beyond.

Although most present-day Americans don’t have to worry about storing food for the winter, we still keep the names for those full Moons. We had the Harvest Moon last month. And tonight, it’s time for the Hunter’s Moon.

The names for both of these full Moons come mainly from parts of Europe and the British Isles. The names were recorded as far back as the early 1700s, but they’d probably been in everyday use for much longer. Variations of the “Hunter’s Moon” label were used by several native tribes and nations in the Americas as well.

The Harvest Moon is usually defined as the full Moon closest to the autumn equinox. Most years, that puts it in September. But this year, October’s full Moon edged out September by just a few hours. So the Hunter’s Moon got bumped into November.

Officially, the Moon will be full at 7:19 a.m. Central Standard Time tomorrow. So it will appear almost as “full” when it rises tomorrow night as it does tonight – extra time to appreciate the brilliant glow of the Hunter’s Moon.

Tomorrow: A giant black hole at the center of a little red dot.

Script by Damond Benningfield

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