StarDate

By Billy Henry

What's StarDate about?

StarDate, the longest-running national radio science feature in the U.S., tells listeners what to look for in the night sky.

Download our free app to listen on your phone

StarDate episodes:

04.23.2024
Immanuel Kant
Immanuel Kant is best known for his ideas about philosophy, from ethics to the nature of knowledge. But he also played a role in the development of an idea about how planets are born. And while many of the details...
04.22.2024
Moon and Spica
Few constellations have as many backstories as Virgo, the virgin. In ancient Greece and Rome, it was linked with several goddesses, each with her own story. In one story, she was Dike, the goddess of justice. She lived when the gods...
04.21.2024
Looking Up
If you look straight up as the sky gets dark this evening, you won’t see much of anything. The region that’s high overhead is populated by some especially faint stars and constellations. But there’s a ring of brighter stars around...
04.20.2024
Kochab
The Little Dipper is famous for the star at the tip of its handle: Polaris, the North Star. Earth’s axis points in that direction, so all the other stars in the night sky appear to circle around it. The second-brightest star...
04.19.2024
Lyrid Meteors
The Lyrid meteor shower is building toward its peak, on Sunday night. The Moon will be almost full then, so its glare will wash out all but the brightest of the “shooting stars.” The shower is the offspring of Comet Thatcher...
04.18.2024
Galactic ‘Twin?’
The Small Magellanic Cloud is a satellite galaxy of the Milky Way. It’s about 200,000 light-years away, it contains hundreds of millions of stars, and it’s easily visible to the eye alone — from the southern hemisphere. And it may...
04.17.2024
Moon and Leo
The heart of the lion stays close to the Moon the next couple of nights. The bright star that marks the lion’s heart is Regulus. It’s to the lower left of the Moon at nightfall this evening, and to the...
04.16.2024
Jupiter and Uranus
Two giants of the solar system huddle close together in the evening twilight the next few days. The viewing window is short, so you need to time it just right to see them. Jupiter and Uranus are low in the west...
04.15.2024
Arcturus
The star Arcturus is a little bit heavier than our own star, the Sun. Yet that small difference has a big effect on the star’s evolution: Arcturus entered a late stage billions of years earlier than the Sun will. Arcturus is...
04.14.2024
Moon and Gemini
The Moon creeps up on the twin stars of Gemini this evening. As night falls, Pollux and Castor are above the Moon. Pollux is on the left, and is a bit brighter than its “twin.” There’s a lot more to Gemini...
04.13.2024
Vanishing Hunter
This time of year is pretty inviting for some evening skywatching. The evening hours are warm but not usually too hot, and spring storm activity generally hasn’t reached its peak — pleasant conditions for watching the stars. Unfortunately, one of the...
04.12.2024
Vaporized Planets
Planetary systems can be violent. In our own solar system, for example, the Moon probably was born from the debris left over when a planet as big as Mars rammed into Earth billions of years ago. And the giant planet...
04.11.2024
Vaporizing Planet
Planets like Earth live in the “Goldilocks zone” — the region around a star where conditions are most comfortable for life. But most planets aren’t so cushy. They’re either far away and cold, or close in and hot. And some...
04.10.2024
Seeing Giants
If you heat up some alphabet soup, you shouldn’t end up with all the letters clumped together — they should be fairly evenly spread throughout the pot. According to the current understanding of the universe, the same thing should apply to...
04.09.2024
Moon and Planets
Europa is one of the more intriguing bodies in the solar system — and one that scientists are especially eager to land a spacecraft on. The big moon of Jupiter may have a global ocean below its icy crust —...
04.08.2024
Future Eclipses
In case you haven’t heard, there’s a big event this afternoon — a total eclipse of the Sun. Totality is visible along a narrow path from Texas to Maine. The parts of the country outside that path will see a...
04.07.2024
Total Eclipse
It’s almost time for the year’s big celestial event: a total eclipse of the Sun. Tomorrow afternoon, the Moon will pass directly between Earth and the Sun. That will block the Sun’s disk. The sky will grow dark, with a...
04.06.2024
Eclipse Flights
In the mythology of ancient Egypt, Apep was the serpent god — the rival of Re, the sun god. He chased Re, and sometimes briefly caught him — creating a solar eclipse. NASA plans to launch an experiment named for the...
04.05.2024
Eclipse Animals
Colonial orb-weaver spiders may have some extra work to do on Monday, during a total solar eclipse. During an eclipse in 1991, scientists watched as spiders in Mexico began tearing down their webs as the sky darkened — something they...
04.04.2024
Eclipse Legends
A total solar eclipse occurs when the Moon passes in front of the Sun, briefly blocking it from view. Before people understood the science, however, they created legends to explain the Sun’s disappearance. Many of those legends involved animals or...
04.03.2024
Eclipse Forecasts
The Great North American Eclipse is coming up on Monday. The Moon will briefly cover the Sun. That will turn day to night along a narrow path across Mexico, the United States, and Canada. The timing of the eclipse is known...
04.02.2024
Corona
On Monday, millions of people will see something they’ve never seen before: the Sun’s corona — its hot outer atmosphere. It extends hundreds of thousands of miles from the surface of the Sun. But it’s so faint that it’s overpowered...
04.01.2024
Solar Eclipse
Many people dread Mondays and the start of the new work week. But there’s something to look forward to next Monday: the Great North American Eclipse. The Moon will completely cover the Sun, turning the sky dark. Tendrils of light...
03.31.2024
The Cup
In Greek mythology, you didn’t have to actually do anything to incur the wrath of the gods. One example is the constellation Crater, the cup, which is in the southeast at nightfall. The story says the god Apollo sent a...
03.30.2024
The Crow
The stories behind the constellations don’t always match the pictures we see in the sky. Consider Corvus, which rises in the southeast in mid-evening. In Greek mythology, it represented a naughty crow. The god Apollo sent the crow to fetch...
03.29.2024
Mars Simulations
No one knows for sure what living on Mars might be like. The planet is bitterly cold and almost completely dry. The atmosphere is less than one percent as thick as Earth’s. And Mars is a long, long way from...
03.28.2024
Mars on Earth
A couple of dozen missions have studied Mars. And they’ve told us a lot about the history of the Red Planet. We know that it was much warmer and wetter in the distant past. And there might have been pockets...
03.27.2024
Struggling Mars
Mars is working hard to climb into view in the dawn sky. But for much of the country, it’s not quite there yet. It’s low in the east-southeast as twilight brightens the sky. It looks like a moderately bright star....
03.26.2024
Soggy Observatories
Most astronomical observatories are up high. That gives them a clearer view of the heavens. But some go deep. They’re submerged in the oceans, or buried deep in the ice at the south pole. They use the water, ice, and the...
03.25.2024
Moon and Spica
The Moon passes by the star Spica the next couple of nights. The brightest star of Virgo is below the Moon as they climb into good view this evening, but closer above the Moon tomorrow night. One prominent lunar feature is...
03.24.2024
Penumbral Eclipse
Anyone standing on the Earth-facing hemisphere of the Moon tonight would see a partial solar eclipse, with Earth covering part of the Sun’s disk. From here on Earth, however, all we’ll see is a penumbral lunar eclipse. The eclipse is...
03.23.2024
Moon and Denebola
The star that marks the tip of the lion’s tail appears to be a loner. It doesn’t have a companion star. And so far, it doesn’t appear to have any planets, either. But it does have the raw materials for...
03.22.2024
Evening Mercury
Only two planets in our solar system are moonless: Mercury and Venus, the planets closest to the Sun. But 50 years ago this month, it looked like Mercury might have to drop off the list — but only for a...
03.21.2024
Moon and Regulus
It’s been more than half a century since the final Apollo mission left the Moon. But scientists are still learning from it. A few years ago, they started examining samples from Apollo 17 that hadn’t been touched before — a...
03.20.2024
A Small Search
It may be a cliche, but it’s true: If at first you don’t succeed, try, try again. That’s certainly the case for the scientists hunting for dark matter. They’ve conducted many big experiments over the past few decades. So far,...
03.19.2024
March Equinox
Spring arrives in the northern hemisphere tonight, at the moment of the March equinox, as the Sun crosses the celestial equator. Day and night are about equal across the entire planet — hence the name “equinox,” which means “equal nights.” The...
03.18.2024
Franz Gruithuisen
When he was just 14 years old, Franz von Paula Gruithuisen found himself in the middle of the Austro-Turkish War. He wasn’t a prisoner or a refugee. Instead, he was a field surgeon. But just a year later, he was...
03.17.2024
Missing Planets
The types of planets you have as neighbors may depend on your neighborhood. The planets discovered in our region of the Milky Way Galaxy come in just about every variety: hot Jupiters, super-Earths, mini-Neptunes, lava planets, ocean planets, and others. But...
03.16.2024
Moon and El Nath
The Moon hangs precariously above a star with a nasty-sounding name tonight: El Nath. The name comes from an Arabic phrase that means “butting” or “goring.” It indicates the star’s position in its constellation — at the tip of one...
03.15.2024
Summer Stars
If you’re ready for a taste of summer, look no farther than the dawn sky. The constellations in view at first light are just what you’ll see as night falls in July and August. Scorpius is low in the south,...
03.14.2024
Moon and Pleiades
Two beautiful objects team up this evening: the Moon and the Pleiades. The little star cluster is close above the Moon. Binoculars will help you pick out some of its brighter stars through the moonlight. The Pleiades has more than a...
03.13.2024
Moon and Jupiter
Scientists are finding so many moons of the solar system’s giant planets that they can hardly keep up with them. By the end of last year, Saturn was in the lead, with 146 confirmed moons. Jupiter — the biggest planet...
03.12.2024
Colorful Stars
Stars come in a whole spectrum of colors, from icy blue to deep red. But our eyes can see the color in only a few stars — most of them are simply specks of white. That’s because most stars are...
03.11.2024
Planetary Poetry
Planetary scientists may see many descriptions this week that are similar to this one: Return to Mimas Blow up the Death Star (moon) and Find hidden oceans. That’s from a presentation about one of Saturn’s moons by Adeene Denton and colleagues at last year’s...
03.10.2024
Puppis
Sometimes, you can have too much of a good thing. That was the case with a constellation that was created thousands of years ago. It was so big that astronomers eventually split it apart. Argo Navis represented the Argo — the...
03.09.2024
Close Moon
The Moon is nowhere in sight the next couple of days. That’s because it’s new — it crosses between Earth and the Sun, so it’s hidden in the Sun’s glare. But coastal residents will definitely feel its presence. That’s because...
03.08.2024
Moving Dipper
The Big Dipper is on the move. Not just its nightly circle around the North Star. And not even its shifting position from month to month. The stars themselves are moving through the Milky Way Galaxy. And most of them...
03.07.2024
Solar Soundings
The Sun is building toward the peak of its magnetic cycle, probably sometime this year. That’s when it produces more sunspots, flares, and giant clouds of charged particles. All of those can have an effect on our technology — knocking...
03.06.2024
Six in Sync
A nearby star has one of the largest families of planets yet seen — an even half-dozen. Only two other known exoplanet families are bigger. But this system is different from the others. All of the planets march in time...
03.05.2024
Coma Cluster
Descriptions of the Coma Cluster of galaxies sound like bad car-dealership commercials. The cluster contains more than a thousand galaxies. They’re bound together by their mutual gravitational pull. The heart of the cluster is about 330 million light-years away. But...

What's StarDate about?

Download our free app to listen on your phone

StarDate episodes:

Immanuel Kant

Moon and Spica

Looking Up

Kochab

Lyrid Meteors

Galactic ‘Twin?’

Moon and Leo

Jupiter and Uranus

Arcturus

Moon and Gemini

Vanishing Hunter

Vaporized Planets

Vaporizing Planet

Seeing Giants

Moon and Planets

Future Eclipses

Total Eclipse

Eclipse Flights

Eclipse Animals

Eclipse Legends

Eclipse Forecasts

Corona

Solar Eclipse

The Cup

The Crow

Mars Simulations

Mars on Earth

Struggling Mars

Soggy Observatories

Moon and Spica

Penumbral Eclipse

Moon and Denebola

Evening Mercury

Moon and Regulus

A Small Search

March Equinox

Franz Gruithuisen

Missing Planets

Moon and El Nath

Summer Stars

Moon and Pleiades

Moon and Jupiter

Colorful Stars

Planetary Poetry

Puppis

Close Moon

Moving Dipper

Solar Soundings

Six in Sync

Coma Cluster