StarDate

The center of the Milky Way Galaxy is packed with treasures: stars, dead stars, gas clouds, and lots of planets. And a new space telescope will spend a lot of its time sorting it all out.

That’s one of several big projects for Nancy Grace Roman Space Telescope, NASA’s next big space observatory. The telescope will see the heavens as clearly as Hubble Space Telescope does. But its view will be much wider. And it’ll study the universe mainly in the infrared – wavelengths that are invisible to the human eye.

Roman will tackle some of the biggest problems in modern science. As one example, it’ll look away from the center of the Milky Way to study more than a billion other galaxies, and to look for exploding stars. That combination will help us understand how the universe is expanding – a key for deciphering the mystery of dark energy.

The telescope’s survey of the center of the galaxy could reveal thousands of new planets. And a special instrument – using a technique proposed by Nancy Roman herself – could provide images of some of those planets. A planet will appear only as a bright dot, with no detail. But breaking down its light will tell us a bit about the planet’s size, temperature, and composition.

The center of the Milky Way is in Sagittarius, which is low in the south at nightfall. Its brightest stars outline a teapot. The heart of the galaxy is in the steam above the spout of the teapot.

Script by Damond Benningfield

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