Radio’s Guide to the Universe

StarDate host Billy Henry

StarDate debuted in 1978, making it the longest-running national radio science feature in the country. It airs on more than 300 radio stations. It has been hosted by Billy Henry since July 2019.

StarDate tells listeners what to look for in the night sky, and explains the science, history, and skylore behind these objects. It also keeps listeners up to date on the latest research findings and space missions. And it offers tidbits on astronomy in the arts and popular culture, providing ways for people with diverse interests to keep up with the universe.

StarDate is a production of The University of Texas McDonald Observatory, which also produces the bi-monthly StarDate magazine.

The Voice of StarDate

Billy Henry, a voice talent, musician, composer, and college lecturer in Austin is the third narrator of the StarDate radio program. Read more »

The Music of StarDate

The StarDate background music was written by Bill Harwell and Patterson Barrett specifically for StarDate.

More Than 40 Years and Counting!

StarDate is radio’s longest-running nationally aired science program. It began in 1977 as a daily telephone message service by McDonald Observatory. It was picked up by Austin radio station KLBJ-FM, and aired as “Have You Seen the Stars Tonight?” beginning in June 1977. With a grant from the National Science Foundation, the program became “Star Date,” and began airing nationally, seven days per week, on October 1, 1978. It quickly reached more than 1,000 stations across the country. Read more »

Today’s Episode

Izar

Russian astronomer Friedrich Wilhelm von Struve discovered and catalogued thousands of binary stars — pairs of stars that are gravitationally bound to each other. But a system that he first saw in 1829 was so striking that he gave it a special name: Pulcherrima — “the most beautiful.” It honors the contrasting colors of the two stars. One looks pale orange, while the other looks blue-white or even green.The system is also known by an even older name: Izar, “the girdle,” because it represents the middle of Boötes, the herdsman. Regardless of what you call it, most skywatchers agree with Struve: Seen through a telescope, the pair is quite beautiful.The orange star is a giant. It’s burned through its original hydrogen fuel and is nearing the end of its life. As a result, it’s puffed up to many times the diameter of the Sun. That “puffiness” caused the star’s outer layers to cool, which is why it looks orange.Its companion is much hotter, so it shines almost pure white. It looks blue or green only when it’s compared to the orange star. It’s less massive than the companion, so it has a lot longer to go before it reaches its own “giant” phase.Boötes is in the east as night falls. Look for its brightest star, brilliant yellow-orange Arcturus. Izar is the first noticeable star to the left of Arcturus. To the eye alone, it looks like a single point of light. But a telescope reveals the true nature of this colorful duo.Script by Damond Benningfield
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Upcoming Topics

  • April 29-May 5: Planet Parade

    The Moon will pass by a parade of planets in the dawn sky late this week, and we’ll have details. We’ll also talk about a protective “blanket” around Earth, a small discovery, and more.

  • April 22-28: Taking a Trip

    A trip around the world would take a while, even in a passenger jet. But it’s the blink of an eye compared to the time it would take to go around a supergiant star.

  • April 15-21: A Cosmic “Dusting”

    Earth is headed through a ribbon of “comet dust” — debris that causes the Lyrid meteor shower. And some of that dust may have been found at the bottom of a river, and we’ll have details.

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