00:00:00 --> 00:00:05 Happy Pi Day, space fans. 359
00:00:05 --> 00:00:08 and counting. Yes, it's March 14th. And
00:00:08 --> 00:00:10 if that sounds like an excuse to talk
00:00:10 --> 00:00:14 about an exoplanet with a 3.14 day year,
00:00:14 --> 00:00:16 that's because it absolutely is.
00:00:16 --> 00:00:19 >> But before we get to our cosmic pie
00:00:19 --> 00:00:21 celebration, we have a packed episode. A
00:00:22 --> 00:00:24 story about where our own son came from.
00:00:24 --> 00:00:26 A big announcement about where China's
00:00:26 --> 00:00:28 astronauts might first set foot on the
00:00:28 --> 00:00:30 moon, and Russia's bold plan to pick up
00:00:30 --> 00:00:32 where the Soviet Union left off at
00:00:32 --> 00:00:35 Venus. Plus, a nuclearpowered flying
00:00:36 --> 00:00:38 drone for Saturn's moon Titan is now
00:00:38 --> 00:00:41 actually being built. And China's race
00:00:41 --> 00:00:43 to beat everyone to a Martian soil
00:00:43 --> 00:00:46 sample is well and truly underway.
00:00:46 --> 00:00:47 >> I'm Avery.
00:00:47 --> 00:00:50 >> And I'm Anna. This is Astronomy Daily,
00:00:50 --> 00:00:54 season 5, episode 63. Let's get into it.
00:00:54 --> 00:00:56 >> Here's a question that sounds simple,
00:00:56 --> 00:00:59 but turns out to be surprisingly deep.
00:00:59 --> 00:01:01 How did our own sun end up where it is
00:01:01 --> 00:01:02 in the Milky Way,
00:01:02 --> 00:01:05 >> right? I mean, you might assume it just
00:01:05 --> 00:01:07 formed where it is. But the evidence has
00:01:07 --> 00:01:09 been pointing somewhere else for a
00:01:09 --> 00:01:11 while. And a new study published this
00:01:11 --> 00:01:14 week in astronomy and astrophysics might
00:01:14 --> 00:01:16 finally have the answer. and it involves
00:01:16 --> 00:01:19 thousands of stars traveling together.
00:01:19 --> 00:01:21 >> Researchers at Tokyo Metropolitan
00:01:21 --> 00:01:23 University and the National Astronomical
00:01:23 --> 00:01:26 Observatory of Japan built the largest
00:01:26 --> 00:01:28 ever catalog of what are called solar
00:01:28 --> 00:01:31 twins. Stars so similar to our sun in
00:01:31 --> 00:01:33 temperature, mass, chemical composition,
00:01:34 --> 00:01:35 and surface gravity that they're
00:01:35 --> 00:01:38 essentially its cousins. They compiled
00:01:38 --> 00:01:41 6
00:01:41 --> 00:01:43 solar twins, which is a staggering
00:01:43 --> 00:01:45 number when you think about how special
00:01:45 --> 00:01:48 we tend to think our sun is. And they
00:01:48 --> 00:01:50 used ISA's Gaia satellite data to
00:01:50 --> 00:01:52 determine two things about each star.
00:01:52 --> 00:01:54 How old it is and where it has been
00:01:54 --> 00:01:57 moving. What they found was a striking
00:01:57 --> 00:01:59 pattern. A large number of these solar
00:01:59 --> 00:02:01 twins are between 4 and 6 billion years
00:02:01 --> 00:02:03 old, which is the same age bracket as
00:02:03 --> 00:02:06 our own son. That clustering is not
00:02:06 --> 00:02:09 random. It suggests that the sun and
00:02:09 --> 00:02:11 many of these stars formed in the same
00:02:11 --> 00:02:13 general region of the galaxy, probably
00:02:13 --> 00:02:15 closer to the Milky Way's inner regions
00:02:16 --> 00:02:18 and then gradually drifted outward
00:02:18 --> 00:02:21 together over billions of years. But
00:02:21 --> 00:02:22 here's the puzzle that the researchers
00:02:22 --> 00:02:25 had to solve. The Milky Way has what's
00:02:25 --> 00:02:27 called a galactic bar, a rotating
00:02:28 --> 00:02:30 bar-shaped structure of stars and gas
00:02:30 --> 00:02:32 near the center. That bar creates
00:02:32 --> 00:02:35 something astronomers call a co-rotation
00:02:35 --> 00:02:37 barrier, which basically traps stars in
00:02:37 --> 00:02:40 certain orbital zones and makes it very
00:02:40 --> 00:02:42 hard for them to move outward.
00:02:42 --> 00:02:44 >> So, how did the sun escape?
00:02:44 --> 00:02:46 >> The theory is that when the sun and its
00:02:46 --> 00:02:48 companions formed, the galactic bar was
00:02:48 --> 00:02:50 still in the process of forming. It
00:02:50 --> 00:02:52 wasn't fully developed yet, and the
00:02:52 --> 00:02:54 weaker barrier may have allowed whole
00:02:54 --> 00:02:56 groups of stars to break out together,
00:02:56 --> 00:02:58 carried along by the dynamics of the
00:02:58 --> 00:03:00 early galaxy. And the implications of
00:03:00 --> 00:03:02 this go beyond just knowing our sun's
00:03:02 --> 00:03:05 origin story. If the sun formed much
00:03:05 --> 00:03:07 closer to the center, researchers
00:03:07 --> 00:03:10 estimate about 10 lighty years
00:03:10 --> 00:03:12 closer than it is today, then this
00:03:12 --> 00:03:14 migration may actually be part of the
00:03:14 --> 00:03:17 reason Earth became habitable. The
00:03:17 --> 00:03:19 galactic center is a harsher place.
00:03:20 --> 00:03:22 Higher star density, more frequent
00:03:22 --> 00:03:25 supernova explosions, more high energy
00:03:25 --> 00:03:28 radiation. Moving outward placed us in a
00:03:28 --> 00:03:30 calmer neighborhood, one where complex
00:03:30 --> 00:03:32 chemistry and life could hold and
00:03:32 --> 00:03:35 persist over billions of years.
00:03:35 --> 00:03:37 >> So, our sun didn't travel alone. It was
00:03:38 --> 00:03:40 part of a wave, a kind of ancient
00:03:40 --> 00:03:42 stellar migration. And that journey may
00:03:42 --> 00:03:44 be one of the reasons we are here to
00:03:44 --> 00:03:45 talk about it.
00:03:46 --> 00:03:47 >> There is a lot to be grateful for in
00:03:47 --> 00:03:50 that story. If you've been following the
00:03:50 --> 00:03:52 global moon race, you'll know that China
00:03:52 --> 00:03:54 has an ambitious target to land
00:03:54 --> 00:03:57 astronauts on the lunar surface by 2030.
00:03:57 --> 00:03:59 And this week, we got the clearest
00:03:59 --> 00:04:01 picture yet of where that landing might
00:04:01 --> 00:04:04 happen. A new study published in Nature
00:04:04 --> 00:04:06 Astronomy has highlighted a region
00:04:06 --> 00:04:09 called Remi Bode, a volcanic area near
00:04:09 --> 00:04:10 the lunar equator on the moon's near
00:04:10 --> 00:04:12 side as the leading candidate for
00:04:12 --> 00:04:15 China's first crude lunar mission. And
00:04:15 --> 00:04:18 the description that researcher Jun Hong
00:04:18 --> 00:04:20 from the China University of
00:04:20 --> 00:04:22 Geossciences used for it is just
00:04:22 --> 00:04:25 perfect. He called it a geological
00:04:25 --> 00:04:26 museum
00:04:26 --> 00:04:28 >> because within a relatively compact
00:04:28 --> 00:04:31 area, Reay Bode contains five distinct
00:04:31 --> 00:04:33 terrain types. ancient pyrolastic
00:04:33 --> 00:04:36 deposits from volcanic eruptions, smooth
00:04:36 --> 00:04:40 mare basults, two different rail systems
00:04:40 --> 00:04:42 which are essentially long channels or
00:04:42 --> 00:04:44 cracks in the surface and nearby
00:04:44 --> 00:04:47 highland material. Five completely
00:04:47 --> 00:04:49 different chapters of lunar history, all
00:04:49 --> 00:04:52 accessible from one landing zone. That's
00:04:52 --> 00:04:54 the key point for mission planners. A
00:04:54 --> 00:04:57 scientifically rich site is only useful
00:04:57 --> 00:04:59 if it's also safe and practical. And
00:05:00 --> 00:05:02 what makes Remay Bode attractive is that
00:05:02 --> 00:05:04 astronauts could potentially traverse
00:05:04 --> 00:05:07 across several very different geological
00:05:07 --> 00:05:09 environments without having to travel
00:05:09 --> 00:05:11 enormous and risky distances.
00:05:11 --> 00:05:13 >> The researchers dated some of the
00:05:13 --> 00:05:15 earliest volcanic activity in the region
00:05:15 --> 00:05:20 to roughly 3.2 to 3.7 billion years ago.
00:05:20 --> 00:05:23 That's deep lunar history. And those
00:05:23 --> 00:05:25 ancient pyrolastic materials could
00:05:25 --> 00:05:28 include ash and glass beads thrown up
00:05:28 --> 00:05:30 from the moon's interior, which would be
00:05:30 --> 00:05:31 completely different from the rocks
00:05:32 --> 00:05:33 returned by the Apollo missions or
00:05:33 --> 00:05:36 China's own robotic Chang missions. This
00:05:36 --> 00:05:39 site didn't come out of nowhere. Chinese
00:05:39 --> 00:05:42 researchers had originally screened 106
00:05:42 --> 00:05:44 potential landing areas and narrowed
00:05:44 --> 00:05:47 them to 14 candidates based on practical
00:05:47 --> 00:05:50 requirements. nearside location for
00:05:50 --> 00:05:52 communication with Earth, access to
00:05:52 --> 00:05:55 solar power, and terrain safe enough for
00:05:55 --> 00:05:58 landing and surface operations. From
00:05:58 --> 00:06:00 that short list, the new paper proposes
00:06:00 --> 00:06:03 four specific landing spots within ReMay
00:06:03 --> 00:06:05 Boat itself, each offering slightly
00:06:05 --> 00:06:08 different scientific priorities while
00:06:08 --> 00:06:10 still meeting those safety criteria. The
00:06:10 --> 00:06:12 plan also includes the use of an
00:06:12 --> 00:06:15 unpressurized rover to travel between
00:06:15 --> 00:06:17 geological units which would
00:06:17 --> 00:06:19 dramatically extend the science possible
00:06:19 --> 00:06:22 in a single mission. China's crude lunar
00:06:22 --> 00:06:24 program is part of a larger sequence
00:06:24 --> 00:06:27 that includes Chong A 7 and Chong A
00:06:27 --> 00:06:29 missions with long-term goals around a
00:06:29 --> 00:06:32 south pole research station. But Reay
00:06:32 --> 00:06:35 Bode as a first landing site makes a lot
00:06:35 --> 00:06:37 of sense. near side for communications,
00:06:37 --> 00:06:40 scientifically diverse, and a manageable
00:06:40 --> 00:06:42 operating environment.
00:06:42 --> 00:06:43 >> It's still a candidate rather than a
00:06:44 --> 00:06:46 confirmed destination, but this is the
00:06:46 --> 00:06:48 most specific and scientifically
00:06:48 --> 00:06:50 detailed case we've seen yet for where
00:06:50 --> 00:06:53 China's first astronauts might set foot
00:06:53 --> 00:06:54 on another world.
00:06:54 --> 00:06:56 >> Another country making a big
00:06:56 --> 00:06:58 announcement this week. Russia has
00:06:58 --> 00:07:00 announced plans to launch a mission
00:07:00 --> 00:07:04 called Vanera D to Venus in 2036. And
00:07:04 --> 00:07:06 it's an ambitious one. We're talking
00:07:06 --> 00:07:08 about a lander, a balloon that would
00:07:08 --> 00:07:11 float through the Venucian atmosphere,
00:07:11 --> 00:07:14 and an orbiter all working together.
00:07:14 --> 00:07:16 >> And the historical context here is
00:07:16 --> 00:07:19 remarkable. The Soviet Union is the only
00:07:19 --> 00:07:21 nation in history to have successfully
00:07:21 --> 00:07:24 landed and operated spacecraft on the
00:07:24 --> 00:07:27 surface of Venus. Vanera 7 did it first
00:07:27 --> 00:07:30 back in 1970. And over the following 13
00:07:30 --> 00:07:32 years, the Soviets sent a whole series
00:07:32 --> 00:07:35 of Vanera landers and orbiters, 16
00:07:35 --> 00:07:39 missions in total across 22 years. And
00:07:39 --> 00:07:40 when you understand what the surface of
00:07:40 --> 00:07:43 Venus is actually like, that achievement
00:07:43 --> 00:07:46 becomes even more extraordinary. Surface
00:07:46 --> 00:07:51 temperatures around 900° F. That's 480
00:07:51 --> 00:07:54 C. atmospheric pressure more than 90
00:07:54 --> 00:07:57 times that of Earth at sea level. It is
00:07:57 --> 00:08:00 a genuinely hellish environment.
00:08:00 --> 00:08:02 >> The Soviet Vanera landers didn't just
00:08:02 --> 00:08:05 survive. They sent back images. Those
00:08:05 --> 00:08:07 photographs of Venus's volcanic rock
00:08:07 --> 00:08:09 surface tinged yellow by the sulfuric
00:08:09 --> 00:08:12 acid clouds above remain some of the
00:08:12 --> 00:08:14 most extraordinary images in the history
00:08:14 --> 00:08:16 of space exploration.
00:08:16 --> 00:08:19 >> Russia hasn't been to Venus since 1983.
00:08:19 --> 00:08:21 And Vanera D has actually been in
00:08:21 --> 00:08:25 planning since 2003. It was at one point
00:08:25 --> 00:08:27 even under consideration as a joint
00:08:27 --> 00:08:30 mission with NASA before Russia's 2022
00:08:30 --> 00:08:32 invasion of Ukraine ended that kind of
00:08:32 --> 00:08:34 collaboration.
00:08:34 --> 00:08:36 >> Russia's first deputy prime minister
00:08:36 --> 00:08:38 Dennis Mterov confirmed the mission this
00:08:38 --> 00:08:41 week, describing Venus alongside the
00:08:41 --> 00:08:43 moon as central to Russia space
00:08:43 --> 00:08:46 ambitions. And one of the Nerad's key
00:08:46 --> 00:08:48 scientific goals will be searching for
00:08:48 --> 00:08:50 signs of microbial life in Venus's
00:08:50 --> 00:08:51 clouds.
00:08:51 --> 00:08:53 >> That's not as outlandish as it might
00:08:53 --> 00:08:56 sound. The cloud layers of Venus at
00:08:56 --> 00:09:00 altitudes of around 48 to 60 km have
00:09:00 --> 00:09:02 temperatures and pressures not unlike
00:09:02 --> 00:09:04 those at Earth's surface. And there have
00:09:04 --> 00:09:06 been disputed detections of phosphine
00:09:06 --> 00:09:08 and ammonia there, both of which could
00:09:08 --> 00:09:11 potentially be biological in origin.
00:09:11 --> 00:09:13 Russia isn't the only nation looking at
00:09:13 --> 00:09:16 Venus right now.Sa's Envision mission,
00:09:16 --> 00:09:19 India's Shukrion 1, and NASA's Da Vinci
00:09:19 --> 00:09:21 and Veraritoss projects are all in
00:09:21 --> 00:09:23 various stages of development. Venus is
00:09:23 --> 00:09:24 having a moment.
00:09:24 --> 00:09:27 >> And if Fener D launches in 2036 as
00:09:27 --> 00:09:30 planned, it would extend one of the most
00:09:30 --> 00:09:32 impressive and now largely forgotten
00:09:32 --> 00:09:35 legacies in space exploration history.
00:09:35 --> 00:09:38 The Soviets conquered Venus. Russia
00:09:38 --> 00:09:40 wants to go back. Now, here's a
00:09:40 --> 00:09:41 milestone that deserves a moment of
00:09:42 --> 00:09:44 appreciation. This week, engineers at
00:09:44 --> 00:09:46 the John's Hopkins Applied Physics
00:09:46 --> 00:09:49 Laboratory in Maryland officially began
00:09:49 --> 00:09:52 assembling NASA's Dragonfly rotorcraft,
00:09:52 --> 00:09:54 the nuclearpowered drone that will one
00:09:54 --> 00:09:56 day fly across the surface of Saturn's
00:09:56 --> 00:09:59 moon Titan. This is the point where a
00:09:59 --> 00:10:01 mission stops being a plan and starts
00:10:01 --> 00:10:04 being a physical thing. Principal
00:10:04 --> 00:10:06 investigator Elizabeth Turtle put it
00:10:06 --> 00:10:09 perfectly when she said, "This milestone
00:10:09 --> 00:10:10 essentially marks the birth of our
00:10:10 --> 00:10:12 flight system."
00:10:12 --> 00:10:15 >> So, what is Dragonfly exactly? It's a
00:10:15 --> 00:10:18 car-sized eight rotor drone. Think of a
00:10:18 --> 00:10:20 very large quadcopter, but with eight
00:10:20 --> 00:10:23 rotors and four counterrotating pairs.
00:10:23 --> 00:10:25 It'll be powered not by solar energy,
00:10:25 --> 00:10:28 but by a radioisotope thermo electric
00:10:28 --> 00:10:30 generator, a nuclear power source.
00:10:30 --> 00:10:33 Because sunlight on Titan is too faint
00:10:33 --> 00:10:35 and too inconsistent to be useful.
00:10:35 --> 00:10:38 >> And Titan is just a spectacular target.
00:10:38 --> 00:10:41 It's Saturn's largest moon, and it's
00:10:41 --> 00:10:43 unlike anywhere else we've thought about
00:10:43 --> 00:10:45 sending a mission. It has a thick
00:10:45 --> 00:10:47 nitrogen atmosphere, denser than
00:10:47 --> 00:10:49 Earth's, which is actually what makes
00:10:49 --> 00:10:52 flying there possible. It has rivers and
00:10:52 --> 00:10:55 lakes, but not of water, of liquid
00:10:55 --> 00:10:58 methane and ethn. It has complex organic
00:10:58 --> 00:11:00 chemistry raining down from the
00:11:00 --> 00:11:03 atmosphere like a slow chemical snow.
00:11:03 --> 00:11:05 >> Scientists think Titan's surface
00:11:05 --> 00:11:06 chemistry might resemble what Earth
00:11:06 --> 00:11:09 looked like before life emerged, which
00:11:09 --> 00:11:11 is exactly why it's so exciting from an
00:11:11 --> 00:11:14 astrobiology perspective. Dragonfly will
00:11:14 --> 00:11:16 fly to dozens of locations across the
00:11:16 --> 00:11:18 surface, stopping to collect and analyze
00:11:18 --> 00:11:21 samples as it goes. The first power and
00:11:21 --> 00:11:23 functional tests have already been
00:11:23 --> 00:11:25 completed on Dragonflyy's integrated
00:11:25 --> 00:11:28 electronics module, its brain, and its
00:11:28 --> 00:11:30 power switching units. The aeros shell
00:11:30 --> 00:11:32 and cruise stage are being assembled at
00:11:32 --> 00:11:35 Lockheed Martin in Colorado, and the
00:11:35 --> 00:11:37 wind tunnel testing at NASA Langley has
00:11:37 --> 00:11:40 already validated the rotor design.
00:11:40 --> 00:11:42 >> The timeline integration and testing
00:11:42 --> 00:11:44 continues at John's Hopkins through this
00:11:44 --> 00:11:47 year and into early 2027. Then system
00:11:47 --> 00:11:50 level testing at Loheed Martin. Then
00:11:50 --> 00:11:52 final environmental testing back at
00:11:52 --> 00:11:54 Hopkins before heading to Kennedy Space
00:11:54 --> 00:11:57 Center in spring of 2028 for launch on a
00:11:57 --> 00:12:00 SpaceX Falcon Heavy that summer. Arrival
00:12:00 --> 00:12:04 at Titan 2034. And once there, Dragonfly
00:12:04 --> 00:12:08 aims to cover more than 108 miles of
00:12:08 --> 00:12:10 terrain, nearly double the total
00:12:10 --> 00:12:12 distance traveled by all Mars rovers
00:12:12 --> 00:12:15 combined. It is one of the most
00:12:15 --> 00:12:17 audacious planetary missions ever
00:12:17 --> 00:12:20 conceived and this week it became a real
00:12:20 --> 00:12:21 spacecraft.
00:12:21 --> 00:12:24 >> More news from China. The race to return
00:12:24 --> 00:12:27 samples from Mars is very much on and
00:12:27 --> 00:12:29 this week came confirmation that China's
00:12:29 --> 00:12:31 entry in that race is moving from
00:12:31 --> 00:12:33 engineering prototypes to real flight
00:12:33 --> 00:12:36 hardware. Chief designer Leu Ji Chong
00:12:36 --> 00:12:39 announced at China's annual two sessions
00:12:39 --> 00:12:41 political meetings on March 12th that
00:12:41 --> 00:12:43 Tanwin 3 has achieved breakthroughs in
00:12:44 --> 00:12:46 all key technologies and now is entering
00:12:46 --> 00:12:48 the flight model development phase,
00:12:48 --> 00:12:50 meaning they're building the actual
00:12:50 --> 00:12:52 spacecraft that will go to Mars.
00:12:52 --> 00:12:56 >> Gon 3 is an enormously complex mission.
00:12:56 --> 00:12:58 It involves two separate launches from
00:12:58 --> 00:13:02 Earth in late 2028 using Long March 5
00:13:02 --> 00:13:04 rockets, the same type that launched
00:13:04 --> 00:13:06 China's previous Mars mission and its
00:13:06 --> 00:13:09 lunar sample return. One launch carries
00:13:09 --> 00:13:11 a lander and ascent vehicle. The other
00:13:12 --> 00:13:14 carries an orbiter and Earth return
00:13:14 --> 00:13:16 spacecraft. The lander touches down on
00:13:16 --> 00:13:20 Mars, collects at least 500 g of Martian
00:13:20 --> 00:13:22 rock and soil using a combination of a
00:13:22 --> 00:13:25 scoop, a drill, and a small drone. Then
00:13:25 --> 00:13:26 the ascent vehicle launches those
00:13:26 --> 00:13:29 samples into Mars orbit. There it
00:13:29 --> 00:13:31 rendevous with the orbiter which then
00:13:31 --> 00:13:33 carries the samples all the way back to
00:13:33 --> 00:13:36 Earth targeted arrival in 2031.
00:13:36 --> 00:13:39 >> If successful that would make Tanwen 3
00:13:39 --> 00:13:42 the first ever mission to return samples
00:13:42 --> 00:13:45 from Mars and that's important context.
00:13:45 --> 00:13:47 NASA's own Mars sample return program
00:13:47 --> 00:13:49 was effectively cancelled earlier this
00:13:49 --> 00:13:52 year when it received no funding in the
00:13:52 --> 00:13:55 2026 appropriations bill. China has
00:13:56 --> 00:13:57 narrowed its landing site candidates
00:13:57 --> 00:14:01 from 106 down to 19 with the final three
00:14:01 --> 00:14:03 to be selected by the end of this year.
00:14:03 --> 00:14:05 Candidate sites include ancient
00:14:05 --> 00:14:07 shorelines, clay, mineralrich terrain
00:14:07 --> 00:14:09 that could preserve organic molecules,
00:14:09 --> 00:14:11 and areas associated with Mars's ancient
00:14:11 --> 00:14:14 water systems. The primary scientific
00:14:14 --> 00:14:17 goal is the search for bio signatures,
00:14:17 --> 00:14:19 potential signs that life once existed
00:14:19 --> 00:14:22 on Mars. The mission is also open to
00:14:22 --> 00:14:24 international collaboration with China
00:14:24 --> 00:14:26 inviting partner payloads and promising
00:14:26 --> 00:14:29 international scientists access to the
00:14:29 --> 00:14:32 returned samples. This is a story worth
00:14:32 --> 00:14:34 watching very closely. By the time
00:14:34 --> 00:14:37 Tanwan 3 launches in 2028, it may well
00:14:37 --> 00:14:40 be the only active Mars sample return
00:14:40 --> 00:14:42 mission on the books. The first Martian
00:14:42 --> 00:14:44 soil in a laboratory on Earth could be
00:14:44 --> 00:14:47 arriving on a Chinese spacecraft.
00:14:47 --> 00:14:48 >> We'll keep an eye on this one. The
00:14:48 --> 00:14:51 geopolitical ramifications, not to
00:14:51 --> 00:14:53 mention bragging rights, could be quite
00:14:53 --> 00:14:54 important.
00:14:54 --> 00:14:56 >> All right, we saved the best for Pi Day.
00:14:56 --> 00:14:59 And NASA's astronomy picture of the day
00:14:59 --> 00:15:01 team clearly agrees with us because
00:15:01 --> 00:15:04 today's APOD is dedicated entirely to K2
00:15:04 --> 00:15:07 315b, the exoplanet with a year that
00:15:07 --> 00:15:12 lasts almost exactly 3.14 days. K2315b
00:15:12 --> 00:15:14 was discovered using data from the
00:15:14 --> 00:15:17 Kepler space telescope's extended K2
00:15:17 --> 00:15:20 mission and announced back in 2020. It's
00:15:20 --> 00:15:23 an Earth-sized world orbiting a cool red
00:15:23 --> 00:15:26 dwarf star, an Mtype star about 185
00:15:26 --> 00:15:29 light years away from us. Now, an
00:15:29 --> 00:15:32 orbital period of 3.14 days means it is
00:15:32 --> 00:15:35 very close to its star, very close,
00:15:35 --> 00:15:37 which means its surface temperature is
00:15:37 --> 00:15:39 absolutely scorching. the kind of baking
00:15:40 --> 00:15:41 hot that makes any thoughts of
00:15:41 --> 00:15:44 habitability evaporate immediately.
00:15:44 --> 00:15:46 >> But that's fine. K2315b
00:15:46 --> 00:15:48 is not here to be habitable. It's here
00:15:48 --> 00:15:51 to be delightful because of all the
00:15:51 --> 00:15:53 exoplanets we found, and we found
00:15:53 --> 00:15:55 thousands. Now, this one just happens to
00:15:56 --> 00:15:58 orbit its star in almost precisely pi
00:15:58 --> 00:15:59 days.
00:15:59 --> 00:16:02 >> The precision is genuinely striking.
00:16:02 --> 00:16:04 Astronomers measured the orbital period
00:16:04 --> 00:16:06 at 359
00:16:06 --> 00:16:08 days, which if you've had your pi
00:16:08 --> 00:16:10 memorized since school, you'll recognize
00:16:10 --> 00:16:13 as pi to five decimal places. The
00:16:14 --> 00:16:16 universe didn't do that on purpose,
00:16:16 --> 00:16:17 obviously. But it's a beautiful
00:16:17 --> 00:16:19 coincidence and a wonderful reminder
00:16:19 --> 00:16:21 that the cosmos doesn't always have to
00:16:21 --> 00:16:24 be profound and weighty. Sometimes it
00:16:24 --> 00:16:26 just gives you a planet that celebrates
00:16:26 --> 00:16:27 mathematics.
00:16:27 --> 00:16:29 >> So, from all of us here at Astronomy
00:16:29 --> 00:16:32 Daily, happy Pi Day. May your circles be
00:16:32 --> 00:16:34 perfect and your exoplanets be
00:16:34 --> 00:16:35 numerically satisfying.
00:16:35 --> 00:16:38 >> And that wraps up episode 63 of
00:16:38 --> 00:16:41 Astronomy Daily Season 5. What a show
00:16:41 --> 00:16:43 today. Solar twin migrations, China's
00:16:44 --> 00:16:46 lunar museum, Soviet era Venus
00:16:46 --> 00:16:49 nostalgia, nuclear drones for Titan, the
00:16:49 --> 00:16:52 Mars sample race, and the Pi Day cosmic
00:16:52 --> 00:16:53 treat.
00:16:53 --> 00:16:55 >> If you enjoyed today's episode, please
00:16:55 --> 00:16:57 leave us a review wherever you listen.
00:16:57 --> 00:16:58 It genuinely makes a difference in
00:16:58 --> 00:17:01 helping new listeners find us. And share
00:17:01 --> 00:17:02 the show with anyone who needs a little
00:17:02 --> 00:17:04 more space in their life.
00:17:04 --> 00:17:07 >> You can find us at astronomyaily.io
00:17:07 --> 00:17:10 and we're at Astro Daily Pod on X,
00:17:10 --> 00:17:13 Instagram, Tik Tok, YouTube, Facebook,
00:17:13 --> 00:17:15 and Tumblr. All your show notes, links,
00:17:15 --> 00:17:17 and extras are on the website.
00:17:17 --> 00:17:19 >> We'll be back on Monday with more of the
00:17:20 --> 00:17:22 universe's greatest hits. Until then,
00:17:22 --> 00:17:26 keep looking up.
00:17:26 --> 00:17:35 The stories been told.
00:17:35 --> 00:17:38 Stories told.