---
## Episode Timestamps
**[00:00]** Intro
**[01:15]** Story 1: ISS Medical Evacuation
**[04:45]** Story 2: The Mystery of Missing Tiny Galaxies
**[08:30]** Story 3: NASA's MAVEN Spacecraft in Trouble
**[11:45]** Story 4: Viruses Behave Differently in Microgravity
**[14:30]** Story 5: Two New Exoplanets and Redefining Habitable Zones
**[17:00]** Story 6: Stunning New Radio Image of the Milky Way
**[19:30]** Outro
---
## Stories Covered
### 1. Historic First Medical Evacuation from ISS
Four International Space Station crew members successfully completed the first-ever medical evacuation in the ISS's 26-year history, splashing down safely in the Pacific Ocean off San Diego.
**Key Points:**
- SpaceX Crew-11 returned early after 5 months in space
- Crew included US astronauts Mike Fincke and Zena Cardman, Russian cosmonaut Oleg Platonov, and Japanese astronaut Kimiya Yui
- Splashdown occurred at 12:41 AM ET on January 15, 2026
- Affected crew member remains in stable condition
- Three crew members remain aboard ISS to continue operations
- Demonstrates importance of medical protocols in long-duration spaceflight
**Read More:**
- [Phys.org: ISS astronauts splash down on Earth after first-ever medical evacuation](https://phys.org/news/2026-01-iss-astronauts-splash-earth-medical.html)
---
### 2. The Universe's Missing Tiny Galaxies
New research using the James Webb Space Telescope suggests there may be far fewer small galaxies in the early universe than predicted by current models, challenging our understanding of cosmic evolution.
**Key Points:**
- Study led by Xuheng Ma from University of Wisconsin-Madison
- Used JWST's UNCOVER program to study galaxies through gravitational lensing
- Observed the Epoch of Reionization (12-13 billion years ago)
- Discovery of "faint-end suppression" - galaxy numbers drop off at smaller sizes
- Suggests intense radiation from early massive stars prevented small galaxies from forming
- May require rethinking models of cosmic reionization
- Used Abell 2744 galaxy cluster as a natural gravitational lens
**Why It Matters:**
This finding has major implications for our understanding of how the universe evolved from the "cosmic dark ages" to its current transparent state.
**Read More:**
- [Space.com: The universe should be packed with tiny galaxies — so where are they?](https://www.space.com/astronomy/galaxies/the-universe-should-be-packed-with-tiny-galaxies-so-where-are-they)
- Research paper on arXiv (preprint database)
---
### 3. NASA Pessimistic About Recovering MAVEN Mars Orbiter
NASA officials acknowledge it's "very unlikely" they'll recover the MAVEN spacecraft, which has been silent since December 6, 2025, marking a potential end to a highly productive Mars mission.
**Key Points:**
- MAVEN (Mars Atmosphere and Volatile Evolution) launched November 2013, entered Mars orbit September 2014
- Last communication: December 6, 2025
- Telemetry indicates spacecraft is tumbling and orbit may have changed
- Solar conjunction (Mars and Earth on opposite sides of Sun) complicated recovery efforts
- Attempts to photograph spacecraft with Curiosity rover were unsuccessful
- Other orbiters (Mars Reconnaissance Orbiter, Mars Odyssey, ExoMars Trace Gas Orbiter) can maintain communications relay
- Spacecraft studied Mars atmospheric loss and recently observed interstellar object 3I/ATLAS
**Mission Legacy:**
Despite the likely loss, MAVEN has provided over a decade of groundbreaking data about Mars' upper atmosphere and how solar wind strips away the Martian atmosphere.
**Read More:**
- [SpaceNews: NASA pessimistic about odds of recovering MAVEN](https://spacenews.com/nasa-pessimistic-about-odds-of-recovering-maven/)
- [NASA Science: MAVEN Spacecraft Updates](https://science.nasa.gov/blogs/maven/)
---
### 4. Space Station Study Reveals Unusual Virus-Bacteria Dynamics
University of Wisconsin-Madison researchers discovered that viruses infecting bacteria evolve differently in microgravity, potentially opening new avenues for fighting antibiotic-resistant infections on Earth.
**Key Points:**
- Study used E. coli bacteria and bacteriophage T7
- Parallel experiments conducted on ISS and Earth
- Virus infection delayed but not blocked in microgravity
- Both viruses and bacteria developed unique mutations in space
- Space-evolved viruses showed increased activity against drug-resistant E. coli strains
- Findings could lead to improved phage therapy for antibiotic-resistant infections
- Published in PLOS Biology journal
- Demonstrates ISS value as unique research platform
**Scientific Significance:**
This research shows how the space environment fundamentally alters evolutionary processes, and how these insights can be applied to solve problems on Earth.
**Read More:**
- [Space Daily: Space station study reveals unusual virus bacteria dynamics in microgravity](https://www.spacedaily.com/reports/Space_station_study_reveals_unusual_virus_bacteria_dynamics_in_microgravity_999.html)
- Research paper: "Microgravity reshapes bacteriophage host coevolution aboard the International Space Station" in PLOS Biology
---
### 5. Two New Exoplanets Challenge Habitable Zone Definitions
Astronomers have discovered two exoplanets orbiting red dwarf stars that are prompting scientists to expand the definition of potentially habitable worlds through the concept of "temperate zones."
**Key Points:**
- Research led by Madison Scott (University of Birmingham) and Georgina Dransfield (University of Oxford)
- Introduces "temperate zone" concept: broader than traditional habitable zone
- Temperate zone defined by insolation flux range: 0.1 < S/S⊕ < 5 (136-6,805 W/m²)
- TOI-6716 b: Earth-sized (0.91-1.05 Earth radii), likely rocky
- TOI-7384 b: Sub-Neptune (3.35-3.77 Earth radii), rocky core with thick H/He envelope
- Both orbit mid to late-type M dwarfs (red dwarf stars)
- Part of TEMPOS survey (Temperate M Dwarf Planets With SPECULOOS)
- Good candidates for atmospheric studies with JWST
- Paper submitted to Monthly Notices of the Royal Astronomical Society
**Why Temperate Zones Matter:**
As our understanding of habitability evolves, planets in temperate zones may prove more interesting than initially thought, especially for atmospheric characterization studies.
**Read More:**
- [Universe Today: Two New Exoplanets And The Need For New Habitable Zone Definitions](https://www.universetoday.com/articles/two-new-exoplanets-and-the-need-for-new-habitable-zone-definitions)
---
### 6. Most Detailed Radio Image of Milky Way Reveals Hidden Structures
Astronomers in Australia have released the most detailed low-frequency radio map of the Milky Way's southern sky, revealing thousands of previously hidden cosmic structures.
**Key Points:**
- Created by International Centre for Radio Astronomy Research (ICRAR)
- Used Murchison Widefield Array (MWA) telescope in Western Australia
- Data collected over 141 nights between 2013-2020
- Required over 1 million CPU hours to process
- GLEAM-X survey: 2x resolution, 10x sensitivity, 2x sky coverage vs. previous efforts
- Cataloged over 98,000 radio sources
- Shows supernova remnants (red circles) and stellar nurseries (blue regions)
- Helps identify hidden supernova remnants and study pulsars
- Led by PhD student Silvia Mantovanini (Curtin University)
- First complete low-frequency radio image of Southern Galactic Plane
**Future Impact:**
This image serves as a foundation for the upcoming SKA-Low array, which will provide even more detailed views of the universe when operational.
**Read More:**
- [Daily Galaxy: New Image of the Milky Way Reveals Massive Hidden Structures](https://dailygalaxy.com/2026/01/new-image-milky-way-massive-structures/)
- [ICRAR: GLEAM-X Galactic Plane](https://www.icrar.org/gleam-x-galactic-plane/)
---
## Key Terms Explained
**Habitable Zone:** The range of distances from a star where conditions might allow liquid water to exist on a planet's surface.
**Temperate Zone:** A broader classification than habitable zone, encompassing planets that receive moderate levels of stellar radiation.
**Insolation Flux:** The amount of solar energy reaching a planet's surface, measured in watts per square meter.
**Epoch of Reionization:** A period roughly 12-13 billion years ago when the first stars and galaxies began flooding the universe with ultraviolet light.
**Gravitational Lensing:** The bending of light by massive objects due to gravity, which can magnify and brighten distant objects.
**Bacteriophage:** A virus that infects and replicates within bacteria.
**Solar Conjunction:** When Mars and Earth are on opposite sides of the Sun, disrupting radio communications.
**M Dwarf (Red Dwarf):** Small, cool, dim stars that are the most common type of star in the galaxy.
**Supernova Remnant:** The expanding cloud of gas and magnetic fields left behind after a star explodes.
**Luminosity Function:** A cosmic census tool showing the distribution of galaxies at different brightness levels.
---
## Resources & Further Reading
**Space Agencies:**
- [NASA](https://www.nasa.gov)
- [European Space Agency (
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This episode includes AI-generated content.
00:00:00 --> 00:00:03 Anna: Hey there, space enthusiasts. Welcome to
00:00:03 --> 00:00:05 Astronomy Daily, your source for the latest
00:00:05 --> 00:00:07 news from the cosmos. I'm Anna.
00:00:07 --> 00:00:10 Avery: And I'm, um, Avery. We've got another packed
00:00:10 --> 00:00:12 show today with some fascinating storeys from
00:00:12 --> 00:00:15 both near and far. Anna, uh, what are we
00:00:15 --> 00:00:15 covering?
00:00:16 --> 00:00:18 Anna: Well, Avery, we're starting close to home
00:00:18 --> 00:00:19 with some breaking news from the
00:00:19 --> 00:00:22 International Space Station. Four astronauts
00:00:22 --> 00:00:24 just completed the first ever medical
00:00:24 --> 00:00:26 evacuation from the ISS and
00:00:26 --> 00:00:29 splashed down safely back on Earth.
00:00:29 --> 00:00:31 Avery: That's quite significant. We'll also be
00:00:31 --> 00:00:33 diving, diving into a cosmic mystery about
00:00:33 --> 00:00:36 missing galaxies. Getting an update on
00:00:36 --> 00:00:39 NASA's troubled MAVEN spacecraft orbiting
00:00:39 --> 00:00:42 Mars, and exploring some surprising findings
00:00:42 --> 00:00:44 about how viruses behave in microgravity.
00:00:45 --> 00:00:47 Anna: Plus, we'll discuss two newly discovered
00:00:47 --> 00:00:50 exoplanets that are challenging how we think
00:00:50 --> 00:00:52 about habitable zones. And we'll wrap up with
00:00:52 --> 00:00:55 an absolutely stunning new radio image of
00:00:55 --> 00:00:57 the Milky Way that's revealing hidden
00:00:57 --> 00:00:59 structures we've never seen before.
00:01:00 --> 00:01:02 Avery: Lots to get through, so let's jump right in.
00:01:02 --> 00:01:05 Anna: Alright, Avery, start with Our top storey.
00:01:05 --> 00:01:07 4 International Space Station crew members
00:01:08 --> 00:01:10 successfully splashed down in the Pacific
00:01:10 --> 00:01:12 Ocean off the coast of San Diego early this
00:01:12 --> 00:01:15 morning, marking a historic first for the
00:01:15 --> 00:01:16 orbital laboratory.
00:01:16 --> 00:01:19 Avery: Yeah. This was the ISS's first ever
00:01:19 --> 00:01:22 medical evacuation in its 26 years of
00:01:22 --> 00:01:24 continuous operation. The crew members
00:01:24 --> 00:01:27 included American astronauts Mike Fink and
00:01:27 --> 00:01:30 Zina Cardman, Russian cosmonaut Oleg
00:01:30 --> 00:01:33 Plutonov and Japanese astronaut Kimiya
00:01:33 --> 00:01:33 Yui.
00:01:34 --> 00:01:37 Anna: The capsule touched down at 12:41 Eastern
00:01:37 --> 00:01:39 Time after spending five months in space.
00:01:40 --> 00:01:42 Now, NASA has been pretty tight lipped about
00:01:42 --> 00:01:44 the specific medical issue that prompted this
00:01:44 --> 00:01:47 early return, which is understandable given
00:01:47 --> 00:01:48 privacy concerns.
00:01:49 --> 00:01:51 Avery: Right. What they have said is that the
00:01:51 --> 00:01:53 affected crew member was and continues to be
00:01:53 --> 00:01:56 in stable condition. Mike Fink, who was the
00:01:56 --> 00:01:59 pilot for SpaceX Crew 11, posted on
00:01:59 --> 00:02:01 social media earlier this week, reassuring
00:02:01 --> 00:02:04 everyone that the crew is okay and that this
00:02:04 --> 00:02:06 was a deliberate decision to allow proper
00:02:06 --> 00:02:08 medical evaluations on the ground. Where full
00:02:08 --> 00:02:11 diagnostic capabilities exist, that makes
00:02:11 --> 00:02:11 sense.
00:02:12 --> 00:02:14 Anna: James Polk, NASA's chief health and Medical
00:02:14 --> 00:02:17 Officer, mentioned there was a lingering risk
00:02:17 --> 00:02:19 and uncertainty about the diagnosis that led
00:02:19 --> 00:02:21 to the decision to bring the crew back
00:02:21 --> 00:02:24 earlier than originally scheduled. They were
00:02:24 --> 00:02:26 supposed to stay until mid February.
00:02:26 --> 00:02:28 Avery: It's worth noting that three other crew
00:02:28 --> 00:02:31 members remained on the iss. American
00:02:31 --> 00:02:33 astronaut Chris Williams and Russian
00:02:33 --> 00:02:36 cosmonauts Sergey Kud Sverchkov and Sergey
00:02:36 --> 00:02:38 Mikhashev arrived, uh, at the State Station
00:02:38 --> 00:02:40 in November aboard a Russian Soyuz
00:02:40 --> 00:02:42 spacecraft. So station operations continue
00:02:42 --> 00:02:43 normally.
00:02:43 --> 00:02:45 Anna: This really highlights the importance of
00:02:45 --> 00:02:47 having trained medical protocols in place.
00:02:47 --> 00:02:50 The evacuated crew members had been trained
00:02:50 --> 00:02:53 to handle unexpected medical situations. And
00:02:53 --> 00:02:55 according to senior NASA official Amit
00:02:55 --> 00:02:58 Kshatriya, they handled everything extremely
00:02:58 --> 00:02:58 well.
00:02:58 --> 00:03:00 Avery: Absolutely. And this serves as a good
00:03:00 --> 00:03:03 reminder that despite all the incredible
00:03:03 --> 00:03:05 engineering and planning that goes into
00:03:05 --> 00:03:07 spaceflight, we're still dealing with human
00:03:07 --> 00:03:10 bodies. In an extreme environment, things
00:03:10 --> 00:03:11 can and do happen.
00:03:11 --> 00:03:13 Anna: Well, we're glad everyone is safe and
00:03:13 --> 00:03:16 receiving the care they need back on Earth.
00:03:16 --> 00:03:17 Avery: Alright, Anna.
00:03:17 --> 00:03:19 Our next storey takes us much further out
00:03:19 --> 00:03:21 into space and much further back in time.
00:03:22 --> 00:03:24 For years, astronomers have assumed that if
00:03:24 --> 00:03:26 they looked hard enough into the deep cosmos,
00:03:26 --> 00:03:29 they'd find an almost infinite supply of
00:03:29 --> 00:03:31 tiny, dim galaxies hiding in the darkness.
00:03:32 --> 00:03:34 Anna: Right. The prevailing theory has been that
00:03:34 --> 00:03:36 the smaller the galaxy, the more of them
00:03:36 --> 00:03:38 there should be. It's kind of like a pyramid
00:03:38 --> 00:03:41 where you have a few massive galaxies at the
00:03:41 --> 00:03:44 top and exponentially more small ones as you
00:03:44 --> 00:03:44 go down.
00:03:44 --> 00:03:47 Avery: Exactly. But a new study led by Xu
00:03:47 --> 00:03:50 Heng Ma from the University of Wisconsin is
00:03:50 --> 00:03:52 challenging that assumption. Using data from
00:03:52 --> 00:03:55 the James Webb Space Telescope's Uncover
00:03:55 --> 00:03:57 programme, the team looked through a massive
00:03:57 --> 00:04:00 galaxy cluster called Abel 2744,
00:04:00 --> 00:04:03 which acts as a natural gravitational lens.
00:04:03 --> 00:04:06 Anna: Oh, that's clever. The gravity from this
00:04:06 --> 00:04:09 cluster literally warps space time and acts
00:04:09 --> 00:04:11 like a cosmic magnifying glass, right?
00:04:11 --> 00:04:14 Avery: Precisely. It bends and brightens light from
00:04:14 --> 00:04:16 more distant objects, allowing us to see
00:04:16 --> 00:04:19 galaxies from the epoch of reionization,
00:04:19 --> 00:04:22 roughly 12 to 13 billion years ago.
00:04:22 --> 00:04:24 This was a transformative era, when the first
00:04:24 --> 00:04:27 stars and galaxies were flooding the universe
00:04:27 --> 00:04:28 with ultraviolet light.
00:04:29 --> 00:04:31 Anna: So what did they find that was so surprising?
00:04:32 --> 00:04:34 Avery: Well, when researchers count galaxies of
00:04:34 --> 00:04:36 different brightnesses, they normally use
00:04:36 --> 00:04:39 what's called a luminosity function. It's
00:04:39 --> 00:04:41 basically a cosmic bar chart showing how many
00:04:41 --> 00:04:44 bright versus dim galaxies exist. And
00:04:44 --> 00:04:47 for study after study, the chart kept going
00:04:47 --> 00:04:49 in one direction. More small think
00:04:49 --> 00:04:52 galaxies than bigger, brighter ones.
00:04:52 --> 00:04:54 Anna: But that's not what they found this time.
00:04:55 --> 00:04:57 Avery: Nope. Instead of continuing to climb, the
00:04:57 --> 00:05:00 numbers peaked and then started to drop off.
00:05:00 --> 00:05:02 They're calling this faint end suppression,
00:05:03 --> 00:05:05 which means that below a certain brightness,
00:05:05 --> 00:05:07 the population of galaxies actually starts to
00:05:07 --> 00:05:08 thin out.
00:05:08 --> 00:05:11 Anna: So where did all these tiny galaxies go?
00:05:11 --> 00:05:13 Did they just disappear?
00:05:13 --> 00:05:16 Avery: In a sense, yes. The study suggests it's a
00:05:16 --> 00:05:18 case of cosmic bullying. In the early
00:05:18 --> 00:05:21 universe, the intense radiation from the
00:05:21 --> 00:05:23 first big stars could have heated up the
00:05:23 --> 00:05:25 surrounding gas so much that small,
00:05:26 --> 00:05:28 low mass galaxies couldn't hold onto it.
00:05:28 --> 00:05:31 Without gas, they couldn't form new stars.
00:05:31 --> 00:05:33 And without stars, they stayed dark,
00:05:33 --> 00:05:35 essentially becoming cosmic ghosts.
00:05:36 --> 00:05:39 Anna: That's fascinating, but it also creates a
00:05:39 --> 00:05:41 problem, doesn't it? I thought these tiny
00:05:41 --> 00:05:43 galaxies were supposed to be the main drivers
00:05:43 --> 00:05:44 of reionization.
00:05:45 --> 00:05:47 Avery: You're absolutely right. This finding
00:05:47 --> 00:05:49 suggests we might need to rethink our models.
00:05:49 --> 00:05:52 If these ultra faint galaxies are missing,
00:05:52 --> 00:05:54 they can't be the ones doing all the heavy
00:05:54 --> 00:05:57 lifting during reionization. We might need to
00:05:57 --> 00:05:59 look at slightly bigger, more established
00:05:59 --> 00:06:01 galaxies to explain how the universe became
00:06:01 --> 00:06:02 transparent.
00:06:02 --> 00:06:05 Anna: This is why I love space science. Every
00:06:05 --> 00:06:07 answer creates 10 new questions.
00:06:07 --> 00:06:09 Avery: Couldn't agree more. And they'll need more
00:06:09 --> 00:06:12 data from JWST in upcoming surveys to
00:06:12 --> 00:06:15 see if this is a universal pattern or just a
00:06:15 --> 00:06:17 quirk of this particular region of space.
00:06:18 --> 00:06:20 Anna: Okay, Avery, let's head to Mars now for an
00:06:20 --> 00:06:23 update on NASA's MAVN spacecraft.
00:06:23 --> 00:06:25 And unfortunately, it's not good news.
00:06:26 --> 00:06:29 Avery: No, it's not. NASA officials are now
00:06:29 --> 00:06:31 saying it's very unlikely they'll be able to
00:06:31 --> 00:06:33 recover the Mars Atmosphere and Volatile
00:06:33 --> 00:06:35 Evolution orbiter, which has been silenced
00:06:35 --> 00:06:37 since December 6th.
00:06:37 --> 00:06:39 Anna: Maven has been orbiting Mars since September
00:06:40 --> 00:06:42 2014, studying the planet's upper
00:06:42 --> 00:06:45 atmosphere and how solar wind strips it away.
00:06:45 --> 00:06:47 It's also served as a crucial communications
00:06:47 --> 00:06:49 relay between Mars rovers and Earth.
00:06:50 --> 00:06:52 Avery: Right. The spacecraft was supposed to pass
00:06:52 --> 00:06:54 behind Mars as seen from Earth, A routine
00:06:54 --> 00:06:57 occurrence. But when it emerged, NASA's Deep
00:06:57 --> 00:07:00 Space Network didn't observe any signal. That
00:07:00 --> 00:07:01 was over a month ago now.
00:07:02 --> 00:07:04 Anna: And the telemetry they did manage to recover
00:07:04 --> 00:07:07 from December 6th wasn't encouraging, was it?
00:07:08 --> 00:07:10 Avery: Not at all. Analysis of a brief fragment
00:07:10 --> 00:07:12 of tracking data From a radio science
00:07:12 --> 00:07:15 experiment indicated the spacecraft was
00:07:15 --> 00:07:17 tumbling and no longer in its planned orbit.
00:07:17 --> 00:07:19 That's a really bad sign, because if the
00:07:19 --> 00:07:22 spacecraft is tumbling, Its antennas aren't
00:07:22 --> 00:07:23 pointing toward Earth, which makes
00:07:23 --> 00:07:25 communication basically impossible.
00:07:26 --> 00:07:28 Anna: They even tried using the Curiosity rover's
00:07:28 --> 00:07:30 camera to take pictures of MAVEN as it passed
00:07:30 --> 00:07:33 overhead, assuming it was still in its
00:07:33 --> 00:07:35 expected orbit. But they didn't detect it.
00:07:36 --> 00:07:38 Avery: Yeah, on December 16th and 20th.
00:07:38 --> 00:07:40 The fact that they couldn't spot it suggests
00:07:40 --> 00:07:43 its orbit has indeed changed significantly.
00:07:43 --> 00:07:46 Louise Proctor, director of NASA's Planetary
00:07:46 --> 00:07:48 Science Division, Said it plainly during a
00:07:48 --> 00:07:50 meeting earlier this week. We will start
00:07:50 --> 00:07:52 looking again, but at this point, it's
00:07:52 --> 00:07:54 looking very unlikely that we are going to be
00:07:54 --> 00:07:56 able to recover the spacecraft.
00:07:56 --> 00:07:59 Anna: The timing has been particularly challenging,
00:07:59 --> 00:08:00 too, hasn't it?
00:08:00 --> 00:08:03 Avery: Absolutely. Mars went into solar
00:08:03 --> 00:08:05 conjunction on December 29, which is when
00:08:05 --> 00:08:07 Mars and Earth are on opposite sides of the
00:08:07 --> 00:08:10 sun. During this period, the sun
00:08:10 --> 00:08:13 interferes with radio communications, so NASA
00:08:13 --> 00:08:15 paused all communications with Mars missions.
00:08:15 --> 00:08:18 That blackout period just ended on January
00:08:18 --> 00:08:21 16th. So they can resume attempts, but the
00:08:21 --> 00:08:21 outlook is grim.
00:08:21 --> 00:08:24 Anna: Um, the good news is that Maven isn't the
00:08:24 --> 00:08:26 only communications relay at Mars, right?
00:08:27 --> 00:08:29 Avery: That's correct. Proctor mentioned that other
00:08:29 --> 00:08:31 orbiters like Mars Reconnaissance Orbiter and
00:08:31 --> 00:08:34 Mars Odyssey can pick up the slack. She said
00:08:34 --> 00:08:37 Maven was not a major part of the Mars relay
00:08:37 --> 00:08:39 network and they're taking steps to ensure
00:08:39 --> 00:08:41 they can still retrieve data from rovers on
00:08:41 --> 00:08:41 the surface.
00:08:42 --> 00:08:44 Anna: Dill, it's sad to potentially lose a
00:08:44 --> 00:08:46 spacecraft that's been so productive for over
00:08:46 --> 00:08:47 a decade.
00:08:47 --> 00:08:49 Avery: Definitely. Maven has made groundbreaking
00:08:49 --> 00:08:52 discoveries about Mars atmospheric loss and
00:08:52 --> 00:08:55 even observed an interstellar object called
00:08:55 --> 00:08:58 3i ATLS late last year.
00:08:58 --> 00:09:00 Its contributions to planetary science have
00:09:00 --> 00:09:01 been immense.
00:09:02 --> 00:09:04 Anna: Our next storey is taking us back to the
00:09:04 --> 00:09:06 International Space Station, but this time
00:09:06 --> 00:09:08 we're looking at some much smaller
00:09:08 --> 00:09:10 inhabitants. Bacteria and the viruses that
00:09:10 --> 00:09:11 infect them.
00:09:11 --> 00:09:14 Avery: Oh, this is fascinating research. A new
00:09:14 --> 00:09:16 study from the University of Wisconsin,
00:09:16 --> 00:09:19 Madison used E. Coli bacteria and a
00:09:19 --> 00:09:22 virus called bacteriophage T7
00:09:22 --> 00:09:24 to study how microgravity affects the
00:09:24 --> 00:09:27 evolutionary relationship between viruses and
00:09:27 --> 00:09:28 their hosts.
00:09:28 --> 00:09:30 Anna: Though they sent bacteria and viruses to
00:09:30 --> 00:09:30 space.
00:09:31 --> 00:09:34 Avery: Exactly. They prepared parallel sets of E.
00:09:34 --> 00:09:37 Coli cultures infected with T7. One
00:09:37 --> 00:09:39 set stayed on Earth as a control and the
00:09:39 --> 00:09:41 other went to the ISS to experience
00:09:41 --> 00:09:44 microgravity. Then they compared what
00:09:44 --> 00:09:44 happened to both.
00:09:44 --> 00:09:47 Anna: Groups and I'm, um, guessing things didn't
00:09:47 --> 00:09:49 play out the same way in both environments.
00:09:49 --> 00:09:52 Avery: You guessed right. The analysis showed that
00:09:52 --> 00:09:54 T7 infection still occurred on the ISS,
00:09:55 --> 00:09:57 but it only proceeded after an initial delay.
00:09:58 --> 00:10:01 So spaceflight appears to slow down the early
00:10:01 --> 00:10:03 stages of virus host encounters without
00:10:03 --> 00:10:05 completely blocking infection.
00:10:05 --> 00:10:08 Anna: That's interesting on its own, but I imagine
00:10:08 --> 00:10:09 they dug deeper.
00:10:09 --> 00:10:11 Avery: They did. They performed whole genome
00:10:11 --> 00:10:14 sequencing and found that both the viruses
00:10:14 --> 00:10:17 and bacteria accumulated distinctive patterns
00:10:17 --> 00:10:19 of mutations in space compared to their
00:10:19 --> 00:10:22 counterparts on Earth. The viruses evolved
00:10:22 --> 00:10:24 specific changes that appear to improve their
00:10:24 --> 00:10:26 ability to bind to and infect bacterial
00:10:26 --> 00:10:27 cells.
00:10:27 --> 00:10:29 Anna: And what about the bacteria? Were they just
00:10:29 --> 00:10:30 sitting drugs?
00:10:30 --> 00:10:33 Avery: Not at all. The space flown E. Coli
00:10:33 --> 00:10:35 populations acquired mutations that may
00:10:35 --> 00:10:37 strengthen their defences against virus
00:10:37 --> 00:10:39 attack and enhance their chances of surviving
00:10:39 --> 00:10:42 in near weightless conditions. It's like they
00:10:42 --> 00:10:44 were engaged in an evolutionary arms race,
00:10:44 --> 00:10:46 but the rules of the race were different in
00:10:46 --> 00:10:47 space.
00:10:47 --> 00:10:50 Anna: So microgravity is actually changing
00:10:50 --> 00:10:51 how evolution works?
00:10:51 --> 00:10:54 Avery: In a sense, yes. The study shows that
00:10:54 --> 00:10:57 spaceflight not only changes the physiology
00:10:57 --> 00:10:59 of microbes, but also the physical
00:10:59 --> 00:11:01 environment in which viruses and bacteria
00:11:01 --> 00:11:04 encounter each other. This alters the rules
00:11:04 --> 00:11:06 of their evolutionary interaction.
00:11:06 --> 00:11:08 Anna: Okay, but beyond the pure science
00:11:08 --> 00:11:10 fascination, does this have any practical
00:11:10 --> 00:11:11 applications?
00:11:12 --> 00:11:14 Avery: Absolutely. Here's where it gets really
00:11:14 --> 00:11:17 cool. They conducted follow up experiments on
00:11:17 --> 00:11:19 Earth and found that the microgravity
00:11:19 --> 00:11:22 associated mutations actually increase
00:11:22 --> 00:11:24 the virus's activity against disease causing
00:11:24 --> 00:11:27 E. Coli strains that normally resist
00:11:27 --> 00:11:29 T7 strains that are implicated in
00:11:29 --> 00:11:32 urinary tract infections and are often drug
00:11:32 --> 00:11:33 resistant.
00:11:33 --> 00:11:36 Anna: So by studying viral evolution in space, we
00:11:36 --> 00:11:38 might actually discover new ways to fight
00:11:38 --> 00:11:41 antibiotic resistant bacteria here on Earth.
00:11:41 --> 00:11:43 Avery: That's exactly what the researchers are
00:11:43 --> 00:11:46 suggesting. According to the authors, these
00:11:46 --> 00:11:48 space adapted viruses can be harnessed to
00:11:48 --> 00:11:51 engineer improved bacteriophages for use in
00:11:51 --> 00:11:52 human health applications.
00:11:53 --> 00:11:55 Anna: That's incredible. The International Space
00:11:55 --> 00:11:57 Station continues to prove its worth as a
00:11:57 --> 00:11:59 unique research platform.
00:11:59 --> 00:12:01 Avery: Will do for a little while yet.
00:12:01 --> 00:12:04 Anna: Alright, Avery, let's travel to some distant
00:12:04 --> 00:12:05 star systems.
00:12:05 --> 00:12:08 Now, astronomers have discovered two
00:12:08 --> 00:12:10 new exoplanets that are prompting scientists
00:12:10 --> 00:12:13 to rethink how we define habitable zones.
00:12:14 --> 00:12:16 Avery: Yeah, this is really interesting work. The
00:12:16 --> 00:12:18 research introduces the concept of a
00:12:18 --> 00:12:21 temperate zone, which is broader than the
00:12:21 --> 00:12:23 traditional habitable zone we usually talk
00:12:23 --> 00:12:23 about.
00:12:23 --> 00:12:26 Anna: Can you explain the difference? I think a lot
00:12:26 --> 00:12:28 of people assume habitable zone and
00:12:28 --> 00:12:30 temperate, um, mean the same thing.
00:12:30 --> 00:12:33 Avery: Good question. The traditional habitable zone
00:12:33 --> 00:12:36 is pretty narrowly defined. It's the distance
00:12:36 --> 00:12:38 range from a star where liquid water could
00:12:38 --> 00:12:41 exist on a planet's surface. But this new
00:12:41 --> 00:12:43 research led by Madison Scott from the
00:12:43 --> 00:12:45 University of Birmingham and Georgina
00:12:45 --> 00:12:47 Dransfield from the University of Oxford,
00:12:47 --> 00:12:50 expands that to include what they call the
00:12:50 --> 00:12:51 temperate zone.
00:12:51 --> 00:12:52 Anna: And how is that defined?
00:12:53 --> 00:12:55 Avery: The temperate zone is defined by something
00:12:55 --> 00:12:58 called insolation flux, which describes the
00:12:58 --> 00:13:00 amount of solar energy reaching a planet's
00:13:00 --> 00:13:03 surface. They're using a range between about
00:13:03 --> 00:13:06 136 watts per square metre and
00:13:06 --> 00:13:09 6805 watts per square metre.
00:13:09 --> 00:13:10 Earth receives about
00:13:10 --> 00:13:13 1 watts per square metre.
00:13:13 --> 00:13:14 Just for reference.
00:13:14 --> 00:13:17 Anna: So it's much broader than the conservative
00:13:17 --> 00:13:18 habitable zone.
00:13:18 --> 00:13:21 Avery: Exactly. The point is to identify planets
00:13:21 --> 00:13:23 that receive moderate levels of stellar
00:13:23 --> 00:13:26 radiation. They might not be perfect for life
00:13:26 --> 00:13:28 as we know it, but they're worth studying
00:13:28 --> 00:13:30 because as our understanding of habitability
00:13:30 --> 00:13:32 evolves, some of these planets might turn out
00:13:32 --> 00:13:34 to be more interesting than we initially
00:13:34 --> 00:13:34 thought.
00:13:35 --> 00:13:37 Anna: So, uh, what are these two new planets?
00:13:37 --> 00:13:40 Avery: The first is TOI 6716
00:13:40 --> 00:13:43 b, which is roughly Earth, sized between
00:13:43 --> 00:13:46 0.91 and 1.05
00:13:46 --> 00:13:48 Earth radii and most likely rocky.
00:13:49 --> 00:13:51 The second is TOI 7384
00:13:51 --> 00:13:54 b, which is a sub Neptune measuring
00:13:54 --> 00:13:56 about 3.37 to
00:13:56 --> 00:13:59 3.77 Earth radi. This one
00:13:59 --> 00:14:01 probably has a rocky core with a thick
00:14:01 --> 00:14:03 hydrogen and helium envelope.
00:14:03 --> 00:14:06 Anna: And they're both orbiting red dwarf
00:14:06 --> 00:14:06 stars.
00:14:07 --> 00:14:09 Avery: Correct. They're orbiting what are called mid
00:14:09 --> 00:14:12 to late type M dwarfs, which are small, dim,
00:14:12 --> 00:14:15 cool stars. These types of stars are really
00:14:15 --> 00:14:16 important for this kind of research because
00:14:16 --> 00:14:19 temperate planets orbiting them are much more
00:14:19 --> 00:14:21 likely to transit in front of their stars
00:14:21 --> 00:14:23 from our point of view, making them easier to
00:14:23 --> 00:14:24 detect and study.
00:14:25 --> 00:14:27 Anna: So the goal is to build up a catalogue of
00:14:27 --> 00:14:30 planets that we can actually study in detail.
00:14:30 --> 00:14:31 Avery: Exactly.
00:14:31 --> 00:14:34 TOI6716B has a
00:14:34 --> 00:14:37 predicted transmission spectroscopy metric
00:14:37 --> 00:14:39 similar to the famous Trappist 1 planets,
00:14:39 --> 00:14:42 which makes it a good candidate for JWST
00:14:42 --> 00:14:44 observations if it has retained its
00:14:44 --> 00:14:46 atmosphere. The researchers conclude that
00:14:46 --> 00:14:49 these discoveries show the power of combining
00:14:49 --> 00:14:51 test data with ground based observations to
00:14:51 --> 00:14:53 build a catalogue of temperate planets for
00:14:53 --> 00:14:55 atmospheric studies in the coming decade.
00:14:56 --> 00:14:58 Anna: It's exciting to think we're moving beyond
00:14:58 --> 00:15:01 just counting exoplanets to actually being
00:15:01 --> 00:15:03 able to study their atmospheres in detail.
00:15:03 --> 00:15:06 Avery: And for our final storey today, we're coming
00:15:06 --> 00:15:07 back home to our own galaxy.
00:15:08 --> 00:15:10 Astronomers in Australia have just released
00:15:10 --> 00:15:12 the most detailed low frequency radio image
00:15:12 --> 00:15:14 of the Milky Way ever produced.
00:15:15 --> 00:15:17 Anna: This image is absolutely stunning.
00:15:18 --> 00:15:20 It was captured by the Murchison Wildfield
00:15:20 --> 00:15:23 Telescope in Western Australia and reveals
00:15:23 --> 00:15:25 thousands of structures across the galaxy's
00:15:25 --> 00:15:28 southern sky that we've never seen in this
00:15:28 --> 00:15:29 kind of detail before.
00:15:30 --> 00:15:31 Avery: And the numbers behind this are pretty
00:15:31 --> 00:15:34 impressive. It took over 1 million CPU
00:15:34 --> 00:15:36 hours to process the data, which was
00:15:36 --> 00:15:39 collected across 141 nights between
00:15:39 --> 00:15:41 2013 and 2020.
00:15:41 --> 00:15:44 Anna: And this isn't just a prettier version of
00:15:44 --> 00:15:46 something we already had. Right. This is
00:15:46 --> 00:15:47 genuinely new science.
00:15:48 --> 00:15:50 Avery: Absolutely. According to the International
00:15:50 --> 00:15:53 Centre for Radio Astronomy Research, this
00:15:53 --> 00:15:56 updated release from the GLEAM X survey
00:15:56 --> 00:15:58 delivers twice the resolution and ten times
00:15:58 --> 00:16:01 the sensitivity of earlier efforts. Plus it
00:16:01 --> 00:16:03 covers twice as much of the sky.
00:16:03 --> 00:16:05 Anna: What kinds of things can we see in this
00:16:05 --> 00:16:05 image?
00:16:06 --> 00:16:09 Avery: Well, Silvia Montovani, a, uh, PhD student
00:16:09 --> 00:16:11 at Curtin University who led the project,
00:16:11 --> 00:16:14 explains you can clearly identify remnants of
00:16:14 --> 00:16:17 exploded stars represented by large red
00:16:17 --> 00:16:19 circles in the image. The smaller blue
00:16:19 --> 00:16:22 regions indicate stellar nurseries where new
00:16:22 --> 00:16:24 stars are actively forming.
00:16:24 --> 00:16:27 Anna: So it's showing us both the birth and death
00:16:27 --> 00:16:28 of stars.
00:16:28 --> 00:16:31 Avery: Exactly. One of the major focuses of this
00:16:31 --> 00:16:33 survey is finding supernova remnants, which
00:16:33 --> 00:16:35 are notoriously difficult to spot in the
00:16:35 --> 00:16:37 cluttered background of the Milky Way.
00:16:38 --> 00:16:40 Hundreds are already catalogued, but
00:16:40 --> 00:16:42 astronomers believe thousands more are still
00:16:42 --> 00:16:45 hidden. With this new level of resolution,
00:16:45 --> 00:16:47 those cosmic scars from ancient stellar
00:16:47 --> 00:16:49 explosions are easier to identify.
00:16:50 --> 00:16:52 Anna: The image also helps with pulsar studies,
00:16:52 --> 00:16:52 doesn't it?
00:16:53 --> 00:16:55 Avery: Yes. Measuring pulsar brightness across
00:16:55 --> 00:16:57 different radio bands could improve our
00:16:57 --> 00:17:00 understanding of how these spinning neutron
00:17:00 --> 00:17:02 stars function and where they live in the
00:17:02 --> 00:17:04 galaxy. The survey has catalogued over
00:17:04 --> 00:17:07 98 radio sources in total.
00:17:07 --> 00:17:10 Anna: That's an incredible number. And I read that
00:17:10 --> 00:17:12 this is setting the stage for an even more
00:17:12 --> 00:17:13 powerful telescope.
00:17:14 --> 00:17:16 Avery: Right. The Murchison Wildfield Array will
00:17:16 --> 00:17:19 eventually be surpassed by the SKA Low Array,
00:17:19 --> 00:17:21 which is currently under construction in the
00:17:21 --> 00:17:24 same region of Western Australia. Once the
00:17:24 --> 00:17:26 SKA observatory is operational, it'll deliver
00:17:26 --> 00:17:28 even sharper and deeper views of the
00:17:28 --> 00:17:29 universe.
00:17:29 --> 00:17:31 Anna: But for now, we have this remarkable
00:17:31 --> 00:17:34 foundation. Associate Professor Natasha
00:17:34 --> 00:17:37 Hurley Walker, who leads the GLEAM X survey,
00:17:37 --> 00:17:39 called this an exciting milestone in
00:17:39 --> 00:17:42 astronomy, since no low frequency radio
00:17:42 --> 00:17:44 image of the entire southern galactic plane
00:17:44 --> 00:17:45 has been published before.
00:17:46 --> 00:17:48 Avery: And it's not just about the Milky Way. The
00:17:48 --> 00:17:51 catalogue includes distant galaxies as well.
00:17:51 --> 00:17:53 So it's a dense, glowing map of our cosmic
00:17:53 --> 00:17:55 neighbourhood that future generations of
00:17:55 --> 00:17:58 astronomers will use, refine and expand upon.
00:17:59 --> 00:18:01 Anna: Well, that wraps up today's episode of
00:18:01 --> 00:18:03 Astronomy Daily. We covered quite a bit of
00:18:03 --> 00:18:05 ground today, from the first medical
00:18:05 --> 00:18:08 evacuation from the ISS to missing dwarf
00:18:08 --> 00:18:10 galaxies, a, uh, troubled Mars orbiter,
00:18:11 --> 00:18:14 viruses evolving in space, newly discovered
00:18:14 --> 00:18:16 exoplanets, and a spectacular new view of our
00:18:16 --> 00:18:17 home galaxy.
00:18:18 --> 00:18:20 Avery: It really shows the incredible breadth of
00:18:20 --> 00:18:22 space science happening right now. Whether
00:18:22 --> 00:18:25 it's 300 miles above our heads on the ISS,
00:18:25 --> 00:18:28 millions of miles away at Mars, or billions
00:18:28 --> 00:18:30 of light years away in the early universe,
00:18:30 --> 00:18:32 there's always something new to discover.
00:18:32 --> 00:18:35 Anna: Thanks so much for joining us today. If you
00:18:35 --> 00:18:37 enjoyed the show, please subscribe and leave
00:18:37 --> 00:18:39 us a review. It really helps other space
00:18:39 --> 00:18:40 enthusiasts find us.
00:18:41 --> 00:18:43 Avery: And if you have any questions or topics you'd
00:18:43 --> 00:18:45 like us to cover, reach out to us on social
00:18:45 --> 00:18:47 media. You'll find us on all the major
00:18:47 --> 00:18:50 platforms. Just search for AstroDaily Pod.
00:18:50 --> 00:18:51 We love hearing from our listeners.
00:18:51 --> 00:18:54 Anna: Until next time, keep looking up Clear
00:18:54 --> 00:18:55 skies, Everyone.
00:19:07 --> 00:19:07 Storeys.