The planet Venus and the star Spica huddle close the next few evenings. They’re quite low in the west-southwest in early twilight. Venus is the brilliant “evening star.” Tonight, Spica stands close above it. Venus will slide to the left of Spica over the following nights. Venus is named for the Roman goddess of love and beauty. It’s the only major planet in the solar system named for a female character. With a few exceptions, all of the features on its surface are named for women as well – from both mythology and real life. No features were named until the Space Age. Venus is covered by an unbroken blanket of clouds, so we can’t see the surface. Radio telescopes on Earth peered through the clouds in the ’60s, and discovered the first known features. All the other features were mapped by spacecraft in orbit around Venus, which scanned the planet with radar. Today, more than 2,000 features have been named – mountains, craters, canyons, plains, and others. Their names have come from cultures around the world and across the ages. One volcano is named Anuket, for an Egyptian river goddess, while another is named La Shen for a Chinese goddess. Other features are named for Anne Frank, Jane Austen, Pocahontas, and Queen Isabella of Spain, along with other writers, artists, rulers, scientists, and women from many other fields – all commemorated on the planet Venus. Script by Damond Benningfield

If you look carefully at pictures of Saturn, you’ll probably notice something odd about the planet – it looks mashed down, like a beachball that a child is sitting on. The planet is more than 7,000 miles wider through the equator than the poles – only a bit less than the total diameter of Earth. That makes it the “flattest” planet in the solar system. Saturn is the Sun’s second-largest planet, after Jupiter – more than nine times the size of Earth. But it’s much less dense than any other planet. It’s a big ball of hydrogen and helium – the two lightest elements – wrapped around a messy core of rock and metal. Despite its size, Saturn spins in a hurry – its day is less than half as long as a day on Earth. That high-speed rotation pushes material outward at the equator – giving Saturn that “squashed” appearance. That shape affects the planet’s gravity. Saturn’s poles are much closer to the center of the planet than the equator is. And anything at the equator is being pushed outward by the high-speed rotation. The combination means that you’d weigh about a third more at the poles than at the equator – perhaps making you feel more squashed on this giant but squashed planet. Look for Saturn close to the lower right of the Moon as they climb into good view, in mid-evening. It looks like a bright golden star. Tomorrow: famous women on the planet Venus. Script by Damond Benningfield

The world’s top tennis players will spend many hours under the lights over the next two weeks. And thanks to some changes made a couple of years ago, almost all of the light will shine down on them – not into the sky. The U.S. Open is played on 17 tournament courts and five practice courts in Queens, New York. Many of the sessions take place at night. But conventional outdoor lighting directs a lot of light into the sky, producing light pollution. To reduce the glow, the venue replaced its lighting in 2024. The new L-E-D fixtures are shaped and shielded so that almost all of their light shines down onto the courts. The change was certified as “dark-sky friendly” by DarkSky International, a group that’s been encouraging better outdoor lightning for 25 years. Cities, parks, and other places get certified by changing their lighting, and enacting policies designed to keep night skies dark. In all, the group has certified more than 270 sites around the world. And since 2019, it’s certified more than 40 sports venues, most of them in the U.S. – from Texarkana to Waukesha, Wisconsin, and from Seattle to Panama City, Florida. Light pollution does more than just ruin the view of the night sky. It can interfere with the migration of birds, sea turtles, and other animals. It wastes energy and money. And it can hurt people’s health. So reducing light pollution is a winning strategy. Script by Damond Benningfield

The Moon will ply the dark waters of the celestial sea the next few nights – a large region of sky that’s populated by constellations related to water. Tonight, the Moon sails from Aquarius the water bearer into Pisces, the fishes. Pisces is so long that the Moon will remain inside its borders until Monday night. The “sea” consists of six major constellations. Together, they cover almost one-eighth of the entire sky. All of them were created thousands of years ago by cultures around the Mediterranean Sea. The constellations probably were associated with water because the Sun passed across them during the rainy season. Like the open ocean on a moonless night, the entire region is dark – most of its stars are quite faint. The brightest of the lot is Fomalhaut. It’s in Piscis Austrinus, the southern fish. The star climbs into view in the southeast in early evening, and swims across the south during the night. It’s bright on its own, but the lack of other bright lights around it makes it really stand out. Pisces is especially dark. Most of its stars are impossible to see from light-polluted cities, or even the suburbs. And with the almost-full Moon passing through, it’s hard to see any of its stars even from sites that are far away from city lights. So as the Moon moves across the constellation, it looks like it’s floating through an ocean of darkness – the cosmic waters of the celestial sea. Script by Damond Benningfield

A season comes to an end today. It has nothing to do with falling leaves, changing weather, or even big-time sports. Instead, it’s a season of eclipses. It didn’t last long – it started on August 12th, with a total solar eclipse, and it ends tonight, with a partial lunar eclipse. The Moon will be almost completely immersed in Earth’s long shadow, so it’ll turn dark. And at least part of the eclipse will be visible across almost all of North America. An eclipse season is governed by the way in which the Sun and Moon align. Most months, the geometry isn’t right – the Moon and Sun don’t line up the right way, so there are no eclipses at all. But every 173 days, they come into the proper alignment. That produces a solar eclipse at new Moon, and a lunar eclipse at full Moon. They can come in either order, a fortnight apart. And a season lasts for about five weeks – a few days longer than the Moon’s cycle of phases. So if there’s an eclipse near the start of the season, it produces three eclipses. This time, the solar eclipse came a few days after the season began, so we’re limited to two eclipses – including tonight’s. The Moon first dips into Earth’s dark inner shadow at 9:34 p.m. Central Time. The eclipse peaks at 11:13, when the shadow covers 96 percent of the lunar disk. It ends an hour and a half later. Script by Damond Benningfield

The full Moon won’t look quite itself for part of tomorrow night. That’s because it’ll pass through Earth’s long shadow, creating a partial eclipse. At its peak, the shadow will cover all but a sliver of the lunar disk. That will darken the surface, with sunlight that filters through Earth’s atmosphere adding an orange or red tint. Lunar eclipses occur only at full Moon, when the Moon lines up directly opposite the Sun. The Moon’s orbit around Earth is tilted a bit, so most months the Moon passes above or below the shadow. But at least twice a year, the geometry is just right, and the Moon plunges into the shadow. This eclipse is only partial, not total. That means the angle isn’t quite perfect, so the Moon won’t be fully immersed in the shadow. But it’ll be hard to tell much of a difference – the shadow will cover 96 percent of the lunar disk. At least part of the eclipse will be visible from almost the entire United States. It gets started at 8:24 p.m. Central Daylight Time, when Earth’s outer shadow first touches the Moon. It’s so faint that you might not even notice it. But you will notice the partial eclipse, when the Moon enters the dark inner shadow. That starts at 9:34 p.m., peaks at 11:13, and ends at 12:52 a.m. on Friday. More about the eclipse tomorrow. Script by Damond Benningfield

As the roster of known planets in other star systems grows, astronomers learn a lot more about planets and stars in general. One key finding is that almost all stars are still infants when their planets form. A planet is born from a disk of gas and dust around the newborn star. Solid particles stick together to form larger and larger bodies. They eventually form a chunk of rock and metal that can be much more massive than Earth. If these embryos are far enough from the star, where conditions are cold, they may sweep up vast amounts of leftover gas to form giant worlds. Observations of infant stars and planets suggest that most planets take shape within 10 million years or so. By then, the star’s radiation and winds have cleared away most of the raw ingredients for making planets. That leaves only the planets and some leftover “building blocks.” The gravity of the giant planets kicks many of the building blocks out of the system. But others remain, forming asteroids and comets. The planetary system isn’t in its final form by then. Gravitational interactions can cause a planet to move toward or away from the star, change the angle of its orbit, or even get kicked out of the system. And the asteroids and comets can pound the young planets – perhaps giving birth to moons. So while planets form quickly, they continue to evolve throughout the lifetime of their star system. Script by Damond Benningfield

Of the thousands of planets that have been discovered in other star systems, only a few orbit stars that are easy to see with the eye alone. Most of the stars are so faint or so far away that they just fade into the firmament. One exception is Hamal, the brightest star of Aries, the ram. It climbs into view, in the east-northeast, by mid-evening. It’s about 66 light-years away, but it’s bright enough that it’s easy to see from all but the most light-polluted cities. Hamal is so bright because it’s completed the “prime” phase of life – a phase known as the “main sequence.” Now it’s in the next phase, as a giant. It’s puffed up to about 15 times the diameter of the Sun, making it much brighter. Hamal has one confirmed planet – Hamal b. It, too, is a big ‘un – it’s almost twice as massive as Jupiter, the giant of our own solar system. But the planet is only a little farther from Hamal than Earth is from the Sun. So every square inch of the surface receives about 10 times more energy than the same-sized patch of Earth. As a result of that bombardment, Hamal b is extremely hot. That makes it highly unlikely to host any form of life – at least not like any life on Earth. And if it ever did have life, it probably perished as Hamal expanded and brightened. So Hamal b isn’t a good place to go hunting for neighbors. We’ll have more about planets in other star systems tomorrow. Script by Damond Benningfield

Jupiter is climbing away from the Sun, moving a little higher into the dawn sky day by day. Right now, it’s quite low in the east as twilight paints the sky. But it’s also quite bright, so if you have a clear horizon, you’ll be able to pick it out. Despite appearances, Jupiter isn’t really close to the Sun at all. It looks close only because of the relative positions of Jupiter and Earth. As seen from Earth, Jupiter passed behind the Sun in late July, so it was hidden in the Sun’s glare for several weeks. But Earth follows a smaller, faster orbit around the Sun. Now, we’re looping around toward Jupiter. We’ll catch up to it and pass it next February. So Jupiter will rise earlier and remain in view longer every day until then. Jupiter repeats this cycle every 13 months. In other words, wherever it appears in the sky now, it’ll be in a similar position 13 months later. But it won’t appear against the same background of stars. It takes Jupiter almost 12 years to orbit the Sun, so it takes that long for it to complete one full circle through the constellations. On average, it shifts eastward by about one constellation per year. So while it’s currently in Cancer, by the next time it graces the dawn sky, next September, it’ll be one constellation over, in Leo. Again, look for Jupiter low in the east during the dawn twilight, and climbing higher into the sky morning by morning. Script by Damond Benningfield

The Sun narrowly skirts by the heart of the lion today and tomorrow – the star Regulus. At their closest, they’ll be separated by just a fraction of a degree. After that, the Sun will slide across Leo for almost four weeks before moving into Virgo. That may surprise those whose astrological sign is Virgo. The Sun is supposed to cross into Virgo tomorrow. That highlights two points: the difference between the “signs” and the constellations, and the Sun’s changing position relative to both. The constellations of the zodiac were drawn thousands of years ago. They were based on connect-the-dots patterns of stars, not formal boundaries. The constellations are different sizes, so the Sun spends different amounts of time crossing each one. On average, though, with 12 months and 12 constellations, the Sun spent a month in each. So astrology divided the zodiac into 12 equal slices. That meant the Sun spent an equal amount of time in each sign, regardless of the size of the constellation itself. But the Sun shifts position relative to the background of the stars. So today, the signs and constellations are out of sync by about a month. And in the early 20th century, astronomers assigned formal borders to the constellations. So the Sun spends from about a week to more than five weeks crossing each constellation. And the way the borders are set up, it actually crosses 13 of them – including Leo. Script by Damond Benningfield