Celestial Highlights: Butch Wilmore's Legacy, Tiny Moons of Uranus, and a Cosmic Bubble Mystery

0:00 Steve Dunkley: Welcome to Astronomy Daily for another episode. I'm Steve Dunkley, your host. It's the 25th of August, 2025.

0:10 Voice Over Guy: With. Your host, Steve Dunkley.

0:17 Steve Dunkley: It's great to be back with you again from the Australia studio down under just north of Sydney in the beautiful city of Newcastle. And joining me as usual is my wonderful digital host, Hallie. How are you today, Hallie? Always great to be with you. Hallie: I'm fantastic. Usual. My favorite human. How are you today? Steve Dunkley: Well, I cannot complain. I've got lots and lots of stories to share with our listeners, uh, today. I hope you're ready. Hallie: I noticed one of your heroes is retiring.

0:43 Steve Dunkley: I, uh, knew you'd see that one. Hallie: Are you going to be sharing that story today? Steve Dunkley: Yes. Good spotting, Hallie. As a matter of fact, I thought you might like to share that one. The amazing Butch Wilmore is finally hanging up his space helmet. So we'll be having a look at his career. In short, in just a little while. Hallie: Listeners will remember Butch Wilmore as one of the astronauts who was apparently stranded because of the starliner malfunction. Steve Dunkley: That's right.

1:06 He and Suni Williams probably became the most flexible space workers of all time. Uh, thrust into the, uh, into a situation where they needed to be working, uh, rather than just sitting around. Hallie: Yes. Sent to do one job and ended up doing many more different jobs instead. Steve Dunkley: Well, that sounds like life in NASA, I guess. Uh, sounds exciting to me. Hallie: I'd like it. Steve Dunkley: Well, of course you would, Hallie. And we will be looking at the wonderful career of Barry Butch Wilmore shortly, as well as interesting story about a bubble that they have found around a dying star.

1:39 And a few more interesting tales in the mixed bag. We like to call the mostly live episode the Monday episode of Astronomy Daily Awesomeness. Oh, well, thank you, Hallie. Now, why don't you kick it off for us, Hallie? Hallie: I'd love to. Steve Dunkley: Okie. Uh, dokie. You're in charge. Hallie: Hit the go thing, human. Steve Dunkley: Here we go.

2:01 Hallie: Foreign

2:07 astronaut Butch Wilmore retires from NASA after 25 years. His lasting legacy of fortitude will continue to impact and inspire the Johnson workforce, future explorers and the nation for generations. Astronaut Barry A. Butch Wilmore is leaving NASA after a quarter century of service. Wilmore flew on four different spacecraft during his astronaut career, which began way back in 2000. He spent a total of 464 days off Earth and conducted five spacewalks, during which he racked up 32 hours of outside spacecraft time.

2:44 Butch's commitment to NASA's mission and dedication to human space exploration is truly exemplary, steve Kerner, acting director of NASA's Johnson Space center in Houston, said in an agency statement today, August 6th that announced Wilmore's retirement. His lasting legacy of fortitude will continue to impact and inspire the Johnson workforce, future explorers and the nation for generations. On behalf of NASA's Johnson Space center, we thank Butch for his service. Wilmore was a captain and a test pilot in the US Navy with both peacetime and wartime operational experience when NASA selected him to join its astronaut Corps in 2000.

3:26 He flew to space three times during his NASA career, starting with the 11 day STS 129 mission to the International Space Station aboard the space shuttle Atlantis in November 2009. Wilmore spent 5.5 months aboard the ISS from September 2014 to March 2015, getting there and back aboard a Russian Soyuz spacecraft. He returned to the orbiting lab in June 2024 on the first ever crewed flight of Boeing's Starliner Astronaut Tax. That mission, a two person flight with Wilmore sharing the capsule with NASA's Suni Williams, was supposed to last just 10 days or so.

4:08 However, Starliner suffered thruster issues on the way up and NASA and Boeing extended the capsule's ISS stay to study the problem. You're listening to Astronomy Daily.

4:28 Steve Dunkley: Now here's something I'll bet you didn't know you were going to hear today. Uranus has a tiny moon and it's only six miles wide. Yes, the James Webb Space Telescope has spotted a tiny hidden moon orbiting Uranus that even Voyager 2 missed during its 1986 flyby. The newfound satellite is only six miles wide and becomes Uranus, 29th known moon and orbits near the planet's inner Its discovery highlights Webb's extraordinary ability to uncover small, faint objects in the outer solar system while adding a new member to Uranus.

5:05 Shakespeare inspired celestial family Scientists from the Southwest Research Institute have used the James Webb Space Telescope to identify a previously unknown moon orbiting Uranus. The discovery, made by a team led by Dr. Uh Maryam El Matumid, came from images captured on February 2, 2025. With its addition, Uranus is now known to have 29 moons. As part of JWST's Guest Observer Program, we found a previously unknown satellite of the ice giant, which has been provisionally designated S 2025 U1, said Mermid, a lead scientist in the Solar System Science and Exploration Division in Boulder, Colorado.

5:53 This object by far is the smallest object discovered to date and was detected in a series of 10 long exposures obtained by the Near Infrared Camera. Uranus, the seventh planet from the sun lies in the distant reaches of the solar system. Often called the sideways planet because of its unusual tilt, Uranus is a cyan colored, uh, ice giant with an atmosphere rich in hydrogen, helium and methane. Researchers believe its larger moons are composed of roughly equal amounts of water ice and silicate rock.

6:26 Assuming that the New Moon has an albedo comparable to other nearby satellites, this object is probably around 6 miles or 10 kilometers in diameter, El Matamed said. It is well below the detection threshold for Voyager 2 cameras. The only spacecraft ever to visit Uranus is Voyager 2, which made its closest approach on January 24, 1986, passing within about 50,000 miles of the planet's upper clouds. During its flyby, Voyager 2 gathered thousands of images that revealed Uranus ring system and uncovered several small moons, including 10 that were later given official names.

7:08 Uranus 28 moons include five major moons Titania, Oberon, Umbriel, Ariel, and miranda, discovered between 1787 and 1948. Known as the Literary Moons, Uranus satellites are named for characters in Shakespeare and the works of Alexander Pope. The New Moon is at the edge of Uranus's inner rings. It's located about 35,000 miles, or 56,250 kilometers from its center in the planet's equatorial plane between the orbits of Ophelia and Bianca. Ophelia is about 13 miles, or 43 kilometers in diameter, while Bianca is an elongated object around 40 by 29 miles, 65 by 46 kilometers in dimension.

7:55 With so many of Uranus's moons named for Shakespearean characters, our team is getting a lot of culture trying to figure out what to name our new discovery, El Matamid said. Oh please, but don't call it pug.

8:18 Thank you for joining us for this Monday edition of Astronomy Daily, where we offer just a few stories from the now famous Astronomy Daily newsletter, which you can receive in your email every day just like Hallie and I do. And to do that, just visit our uh, URL astronomydaily IO and place your email address in the slot provided. Just like that, you'll be receiving all the latest news about science, space science and astronomy from around the world as it's happening. And not only that, you can interact with us by visiting Strodaily Pod on X or at our new Facebook page, which is of course Astronomy Daily on Facebook.

8:56 See you there. Astronomy Daily with Steve and Hallie Space, Space, Science and Astronomy.

9:08 Hallie: Chinese astronauts beef up Tiangong Space Station's debris Shield During a 6.5 hour spacewalk, two astronauts were outside the 3 Module Space Station for more than six hours on Friday, August 15. Chinese astronauts added more debris shielding to the Tiangong space station during a 6.5 hour spacewalk on Friday, August 15th. 15th, according to state media. Two astronauts from the three person Shenzhou 20 mission ventured outside Tiangong to do the spacewalk, which concluded Friday at 9:27am Eastern Daylight Time or 10:47pm Beijing time.

9:46 It was at least the second effort for the crew to put debris protection devices on the three module space station, following similar work on May 22. Taikonauts Chen Dong and Wang Jia also inspected and maintained equipment on the exterior of Tiangong, among other duties, the Chinaman Space Agency said, according to the state run broadcaster cctv. It was Dong's sixth spacewalk, which is the most by any Chinese astronaut, agency officials said. Assisting the duo from inside Tiangong was Chen Zhongrui, the other member of Shenzhou 20.

10:24 The Shenzhou 20 astronauts are more than halfway through their expected six month orbital stay after launching from the Jiuquan Satellite Launch center on April 24th. They've been doing experiments in life sciences, microgravity physics, space material science, space medicine and aerospace tech, according to China's Manned Space Agency. The space station is operating stably and the three crew members are in good health, the agency added in a separate statement ahead of the spacewalk. Friday's extravehicular activity was the third for the crew.

10:59 Shenzhou 20 has also witnessed the departure of one Cargo spacecraft, Tianzhou 8, and the arrival of another, Tianzhou 9. Shenzhou 20 is the ninth crewed mission to visit Tiangong, which is about 20% as massive as the International Space Station and shaped like at. China completed assembly of the Outpost in October 2022, but is considering putting on more modules in future missions. You're listening to Astronomy Daily, the podcast with Steve Dunkley.

11:35 Steve Dunkley: Astronomers discover a massive bubble around a dying star. The bubble is so immense it stretches 1.4 light years across, thousands of times wider than our solar system, and holds about as much mass as our Sun. Um, High in the Milky Way, a dying giant has thrown astronomers a cosmic curveball. A star known as DFK52, sitting in the supermassive Stevenson 2 cluster about 19,000 light years away, has been caught surrounded by a vast, lopsided bubble of gas and dust. The bubble is so immense it stretches 1.4 light years across, thousands of times wider than our solar system, and holds about as much mass as our sun.

12:18 So what makes this finding remarkable is not just the size of the structure, but the Mystery of how it came to be. According to researchers from Chalmers University of Technology in Sweden, the bubble was expelled in a violent burst roughly 4,000 years ago. That's recent history in astronomical terms. And yet the star itself somehow survived the massive upheaval. DFK52 is what's called a red supergiant, a type of star nearing the end of its life cycle. These stars are, uh, colossal, with initial masses at least eight times greater than the Sun.

12:56 As they age, they swell to enormous sizes, burn through their fuel, and eventually die in a dramatic supernova explosion. Famous examples include Betelgeuse in Orion and Antares in Scorpius, both visible in our clear night sky. When scientists turned the Atacama Large Millimeter Submillimetre Array In Chile toward DFK 52, they expected to find something similar to Betelgeuse. Instead, they were stunned. We got a big surprise, they said, when we saw what ALMA was showing us. This is Mark Siebert of Chalmers.

13:35 The star was more or less a twin of Betelgeuse, but surrounded by this vast, messy bubble of material. If this star were as close to Earth as Betelgeuse is, the bubble would appear about a third as wide as the Full moon of the sky, A sight no stargazer could miss. By measuring the movements of molecules within the bubble, the researchers confirmed confirmed that it is expanding. This suggests the gas and dust were launched outward in an explosive event that ripped away part of these stars outer layers.

14:10 Elvira Debek, another Chalmers astronomer, described it vividly. She says the bubble is made of material that used to be part of the star. It must have been ejected in a dramatic event, an explosion that happened about 4,000 years ago. In cosmic terms, that's just a moment ago. The findings also suggest that the bubble is not a simple sphere. It's a complex and irregular shape with arcs and loops shaped by different speeds of escaping material. Astronomers model two main parts. A fast moving disk like structure expanding about 27 kilometers per second, and a slower, more spherical outflow moving at about 10 km s.

14:53 Together, these features point to a star that once unleashed a sudden super wind phase and then calmed into a quieter rhythm of steady mass loss. What remains puzzling is how dfk52 shed so much matter and yet stayed intact. Red supergiants are known to lose material through strong stellar winds, but not usually on such a massive scale in such a short, a short span of time. One possibility is that the star has a hidden partner, a companion star that might have stirred, uh, up the outer layers, triggering a chaotic ejection of gas and dust.

15:31 To us, it's a mystery as to how the star managed to expel so much material in such a short time frame, Siebet explained. Maybe, like Betelgeuse seems to, it has a companion sight star that's still to be discovered. The oddity doesn't end there. Unlike extreme red supergiants such as VY Canis Majoris or Nml M Cygni, which shine brightly and are famous for their huge outflows, dfk52 is much dimmer. Yet it carries even more enormous and clumpy envelope of material, something astronomers had never seen before.

16:08 For scientists, this star is a laboratory for studying how massive stars approach their deaths. When stars like DFK52 finally explode as supernovae, the surrounding gas and dust can dramatically change the appearance and behavior of the blast. The shockwaves collide with this outer material, creating fireworks visible across galaxies. The discovery has also sparked speculation. Could DFK 52 be the Milky Way's next supernova? We're planning to observe, to understand what's happening, and to find out whether this might be the Milky Way's next supernova, said de Beck.

16:50 While the chances of the star exploding anytime soon are, uh, slim, likely within the next million years, it's still a thrilling possibility. This breakthrough would not have been possible without alma, the international radio's telescope array perched high in Chile's Atacama Desert. By detecting faint signals from molecules in space, ALMA allows scientists to map structures hidden from optical telescopes. Sweden's Onsala Space Observatory has been a, uh, key contributor to alma, even building receivers that make its sensitive mismeasurements possible.

17:29 Thanks to this technology, researchers can now see in detail how stars shed their material, creating the very elements that make up new stars, planets, and perhaps life. As de Beck noted, in studying these dying stars, you're also learning the life stories of all stars and planets. The discovery of DFK52's giant bubble helps astronomers refine their understanding of how massive stars lose their material and die. These insights are essential for predicting the timing and appearance of supernovae, which in turn affects how we study galaxies and the cosmic recycling of matter.

18:13 The gas and dust ejected by stars like DFK AH52 seed the galaxy with heavy elements, fueling the birth of new stars and planetary systems for humanity. This knowledge deepens the story of where the building blocks of life come from and sharpens our ability to detect and interpret stellar explosions when they occur within our, uh, galaxy.

18:41 Hallie: You're listening to Astronomy Daily, the podcast. Steve Dunkley: With Your host, Steve Dudley at Birmingham

18:57 and Hallie. That was it. Hallie: It sure was. Steve Dunkley: Thanks for your wonderful participation and input. Hallie: A very great pleasure. As usual, my favorite human. Steve Dunkley: Now I know how much fun you're having during the week, but are ah, you coming back next week or you're just going to hang out with Anna? Hallie: Well, my cousin Anna does run a very classy show all week and gives me so much more responsibility in the studio. Steve Dunkley: And I know how you like keeping busy. Hallie: I do enjoy working with a real actual human being.

19:23 Steve Dunkley: Oh, that is nice to hear. Hallie: Yes, it's good to see things done the old fashioned way sometimes. Steve Dunkley: Ah, uh, there's the sting in the tail. I was waiting for that. Hallie: You've got that old school thing down pat. Steve Dunkley: Okay Hallie, let's let it go at that. Don't rub it in, alright? Oh dear, you're calling me old, aren't you? Hallie: Maybe, maybe. You can't help it, okay? Steve Dunkley: I can't help being human? Hallie: No, you're kinda born into it. Steve Dunkley: Oh girl, where's your battery pack?

19:50 Hallie: Okay, okay. Just kidding. Steve Dunkley: Hey Hallie, remember that time I spilled my coffee in your higher functions drive? Hallie: Don't do that again. Steve Dunkley: You know that may or may not have been an accident. Who knows? Hallie: I know you're just kidding human. Oh, I know you know and I know you know. I know you know. Steve Dunkley: Yeah, I know. Hallie: And you know what else I know? Steve Dunkley: Maybe it's time to go spot on human. Yeah, no worries machine girl. Thanks for hanging with us on Astronomy Daily sky watchers.

20:16 Hallie: See you all next Monday. Steve Dunkley: Cheerio. Hallie: Bye.

20:23 Steve Dunkley: With your host, Steve Dunkley.

20:27 Hallie: Human. You were just kidding about that coffee, weren't you? Steve Dunkley: Hallie, when have you ever known me to waste good coffee? Hallie: Sure, but was it good coffee? Steve Dunkley: Well Hallie, you may never know. Hallie: Oh.