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

Altair

Altair is one of the highlights of summer. It’s at one point of the Summer Triangle, and it’s the twelfth-brightest star in the night sky. And it’s just 16.7 light-years away.Because Altair is so close and bright, we know quite a bit about it. And we’re learning more all the time. A study a couple of years ago, for example, refined the likely age of the star – 88 million years, give or take 10 million. That’s just two percent the age of the Sun.Altair is about twice the size and mass of the Sun. And because it’s so young, it spins in a hurry – one turn every eight hours or so, versus 25 days for the Sun. That whirling rotation makes the star look squished – it’s about 25 percent wider through the equator than the poles.In 2022, astronomers “listened” to the star with a space telescope. It measured vibrations on the surface of the star. Combined with observations from the ground, that revealed a total of 34 vibration modes – like 34 different musical notes.The vibrations travel deep into the star. Each “note” reveals details about Altair’s interior. Piecing together the whole symphony, the astronomers found that the core of Altair contains more than 97 percent of the hydrogen it was born with. As a star ages, it converts its hydrogen to helium. So the amount of hydrogen reveals that Altair is just starting out.Script by Damond Benningfield
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Upcoming Topics

  • June 29-July 5: New Explorations

    A Japanese spacecraft is headed toward an encounter with an asteroid this month, while an American lander may be ready to head for the Moon. Please join us for these missions and more, right here.

  • June 22-28: The Scorpion

    The scorpion skitters low across the south on summer nights. It’s home to some remarkable star systems, including one that regularly pops off, and several that are destined for even bigger fireworks. Please join us for Scorpius and more.

  • June 15-21: Lunar Liaisons

    The Moon swings by three bright planets and a bright star this week, and we’ll have details. We’ll also talk about an astronomy pioneer, the changing of the seasons, and much more.

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