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StarDate Podcast

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

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

United States

Description:

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

Twitter:

@stardate

Language:

English

Contact:

512-475-6760


Episodes

Moon and Spica

3/21/2019
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By Earthly standards, a hard vacuum surrounds the surface of the Moon. Yet it’s not a complete vacuum — the Moon has a thin atmosphere. Much of the material that makes up the atmosphere comes from the surface. It’s kicked off of rocks and dirt by the solar wind or by impacts by tiny space rocks. And some of the material may come from inside the Moon — mainly from dormant volcanoes. Billions of years ago, volcanic activity might have given the Moon a much thicker atmosphere. Bombardment by...

Duration:00:02:19

More Vernal Equinox

3/20/2019
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Spring begins in the northern hemisphere today, as the Sun crosses the equator heading north. For many of us in modern times, that moment — the spring equinox — is little more than a notation on the calendar. But to many cultures in bygone centuries, it was a time for celebration, as the Sun warmed the earth and banished the long, cold nights of winter. For the Lakota of the Great Plains, the equinox marked the beginning of a new year. They commemorated the event with the start of a journey...

Duration:00:00:14

Vernal Equinox

3/19/2019
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Sometimes, you just can’t trust your lying eyes. If you observe the sky, for example, you might see the Sun rising and setting every day and conclude that it circles around Earth. And that’s what most people thought until about five centuries ago. They were wrong, of course — their eyes deceived them. Not everyone agreed with that idea, though. More than 2400 years ago, a Greek philosopher proposed that Earth, Sun, Moon, and planets all orbit the “central fire” of the universe. And a...

Duration:00:00:14

Moon and Regulus

3/18/2019
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The evolution of a star is dominated by one thing: the star’s mass. Heavy stars live short but brilliant lives. Lightweight stars are less showy, but they live a long time. And when there are two stars in a single system, a difference in mass can change the evolution of both. A prime example is Regulus, the brightest star of Leo, the lion, which is just a whisker away from the Moon tonight. The bright star we see as Regulus has a tiny companion — a white dwarf. It’s the dead core of a...

Duration:00:00:14

The Dominator

3/17/2019
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The Sun exerts a mighty influence on the space around it. Our star holds on to eight major planets, perhaps hundreds of dwarf planets, and a trillion or more smaller chunks of rock and ice. The key to this domination is the Sun’s mass. The Sun contains 99.9 percent of all the material in the solar system — more than 300,000 times the mass of Earth. That great heft generates a powerful gravitational pull. In fact, the Sun’s gravity dominates a “bubble” of space that spans more than two...

Duration:00:02:19

Spinning Stars

3/16/2019
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The beautiful Pleiades is high in the west as night falls at this time of year. The star cluster looks like a tiny dipper. Right now, it stands above bright orange Mars by about the width of your fist held at arm's length. The cluster contains hundreds of stars. All of them were born at the same time, from the same cloud of gas and dust. That makes the Pleiades a great laboratory for studying how stars evolve. Since all of the stars were born from the same raw materials, any differences are...

Duration:00:02:19

Radio Survey

3/15/2019
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When astronomers look at the universe, stuff often gets in the way — from clouds to airplanes to asteroids. And the operators of an extensive new survey of the sky have something else to avoid: the satellites that broadcast Sirius-XM radio. The VLA Sky Survey is using the Very Large Array — a collection of 27 radio antennas in New Mexico — to make the most detailed radio maps of the sky ever. But the satellites broadcast at some of the same frequencies the VLA is studying. In fact, the...

Duration:00:02:19

Getting Ready

3/14/2019
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A giant telescope is a marvel of science and engineering — tons of glass and steel that are molded into an impressive scientific instrument. But it's also a marvel of civil engineering — years of work just to get the site ready for construction. Consider GMT — the Giant Magellan Telescope. When it's finished, it'll be the largest telescope in the world, with a main mirror almost as big as a basketball court. It's being built atop Cerro Las Campanas, an 8200-foot mountain in Chile. The...

Duration:00:02:19

Making Mirrors

3/13/2019
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The mirrors of most telescopes consist of a single big piece of glass — a reflective surface that gathers and focuses the light from distant objects. But there's a limit to how big you can make a single mirror. Bigger mirrors are made of smaller segments that are pieced together like the tiles on a floor. A jumbo telescope that's under construction uses a slightly different approach. GMT — the Giant Magellan Telescope — will consist of seven mirrors. Each of them will be around the limit...

Duration:00:02:19

Moon and Aldebaran

3/12/2019
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For most of its lifetime, a star wages an internal battle — a battle between radiation and gravity. In the end, though, gravity always wins. A star that’s nearing the final stages of that battle stands near the Moon tonight. Aldebaran, the brightest star of Taurus, is to the upper left of the Moon at nightfall. A star is powered by the nuclear fusion reactions in its core. For stars like the Sun, hydrogen atoms are smashed together to make helium. When the hydrogen is gone, gravity...

Duration:00:02:19

Making Stars

3/11/2019
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Most galaxies of any appreciable size are giving birth to new stars. But some are a lot better at it than others. In fact, early results from a survey of star-forming galaxies suggests that smaller ones are better at it than bigger ones. Stars are born from stellar nurseries — collapsing clouds of gas and dust. The clouds break apart into smaller clumps that then form stars. Individual nurseries can give birth to anywhere from a few stars to hundreds of thousands of them. Astronomers are...

Duration:00:02:19

Moon and Mars

3/10/2019
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There’s a lot of talk these days about sending people to the Moon and Mars — not just for a few days, but for weeks or longer. Such expeditions won’t be able to get all the supplies they need from Earth. Instead, they’ll need to live off the land. They might use ice to provide drinking water, oxygen, and rocket fuel, for example. And they might be able to use the dirt, too. In fact, research teams around the world are making simulated Moon and Mars dirt for testing. The dirt could be used...

Duration:00:02:19

Stellar Enemies

3/9/2019
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Orion is a big constellation with a big story. The story is so big, in fact, that it incorporates several other constellations. Some of them surround the hunter, while another is on the opposite side of the sky — a separation designed to keep two mortal enemies apart. Orion is high in the south as night falls. The bright orange star Betelgeuse marks his shoulder, and blue-white Rigel is his foot. His three-star belt stands between them. In mythology, Orion was one of the major celebrities...

Duration:00:02:19

More Kepler

3/8/2019
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Astronomers recently reported the sixth planet orbiting a star in the constellation Aquarius. Known as K2-138g, it’s been classified as a “sub-Neptune” — a planet that’s bigger than Earth, but smaller than Neptune, the Sun’s outermost planet. That brings the number of systems with at least six known exoplanets to nine. And most of those worlds were discovered with the most successful planet hunter to date: the Kepler space telescope, which was launched 10 years ago and wrapped up its...

Duration:00:02:19

Kepler

3/7/2019
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The most-prolific planet hunter to date took flight 10 years ago today. By the time it was retired, late last year, Kepler had discovered about 5500 confirmed or possible planets. And astronomers will sift through its decade of observations for decades more. The space telescope discovered planets by looking for a star to grow a tiny bit fainter as a planet passed in front of it, blocking some of its light. How much the star faded, and for how long, revealed the planet’s size. And repeated...

Duration:00:02:19

Galactic Magnet

3/6/2019
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The center of the galaxy is dangerous. It’s dominated by a supermassive black hole. And to make things more hazardous, one of its closest neighbors is a magnetar — the ultra-dense corpse of a once-mighty star. It spins once every 3.8 seconds, emitting a “pulse” of energy with each spin. That makes it a pulsar. And it has a magnetic field that may be a trillion times stronger than Earth’s — fatal at a range of thousands of miles. Quite a few pulsars inhabit the galaxy’s core. But the...

Duration:00:02:19

Magnetars

3/5/2019
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You don’t want to get close to a magnetar. From a distance of hundreds of miles, the universe’s most powerful magnets would tug at the electrons in your body’s atoms, pulling the atoms out of shape — and causing you to fall apart. The first magnetar was discovered 40 years ago today. A wave of gamma rays swept across the solar system — the most powerful outburst seen to that time. It was detected by spacecraft in Earth orbit and beyond, allowing astronomers to pinpoint the source: clouds of...

Duration:00:02:19

Black Widows

3/4/2019
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Pulsars don’t play well with others. Some of them are destroying their companions, earning them an unflattering nickname: black widows. Pulsars are the ultra-dense corpses of once-mighty stars. They’re up to a couple of times as massive as the Sun, but no bigger than a city. They’re called “pulsars” because they spin rapidly — up to hundreds of times per second — and we see “pulses” of energy with each spin. Some pulsars have companions — stars or the stellar wannabes known as brown...

Duration:00:02:19

Double Cluster

3/3/2019
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One of the jewels of the winter Milky Way stands high in the northwest this evening. It’s actually two jewels that are quite close together — a pair of star clusters known as the Double Cluster. And they really do represent jewels — the jeweled handle of the sword of Perseus, the hero. Individually, the clusters are cataloged as NGC 884 and 869. Although they were known to ancient skywatchers, their true nature wasn’t discovered until the 18th century, when William Herschel studied them...

Duration:00:00:14

Orion Veil

3/2/2019
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A brilliant young star in the Orion Nebula apparently doesn’t want any more brothers or sisters. It’s blowing an intense “wind” that’s clearing out much of the gas around it — pushing away the raw materials for making more stars. The star is known by the somewhat clumsy name of Theta-1 Orionis C. It’s the heaviest member of the Trapezium — a cluster of hot, massive young stars. The star is many times heavier than the Sun, tens of thousands of degrees hotter, and hundreds of thousands of...

Duration:00:00:14