The Sun’s Great Galactic Road Trip, China’s Moon Museum & a Pi Day Planet

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Language: en

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Happy Pi Day, space fans. 3.14159


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and counting. Yes, it's March 14th. And


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if that sounds like an excuse to talk


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about an exoplanet with a 3.14 day year,


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that's because it absolutely is.


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>> But before we get to our cosmic pie


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celebration, we have a packed episode. A


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story about where our own son came from.


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A big announcement about where China's


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astronauts might first set foot on the


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moon, and Russia's bold plan to pick up


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where the Soviet Union left off at


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Venus. Plus, a nuclearpowered flying


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drone for Saturn's moon Titan is now


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actually being built. And China's race


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to beat everyone to a Martian soil


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sample is well and truly underway.


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>> I'm Avery.


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>> And I'm Anna. This is Astronomy Daily,


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season 5, episode 63. Let's get into it.


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>> Here's a question that sounds simple,


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but turns out to be surprisingly deep.


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How did our own sun end up where it is


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in the Milky Way,


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>> right? I mean, you might assume it just


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formed where it is. But the evidence has


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been pointing somewhere else for a


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while. And a new study published this


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week in astronomy and astrophysics might


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finally have the answer. and it involves


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thousands of stars traveling together.


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>> Researchers at Tokyo Metropolitan


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University and the National Astronomical


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Observatory of Japan built the largest


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ever catalog of what are called solar


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twins. Stars so similar to our sun in


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temperature, mass, chemical composition,


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and surface gravity that they're


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essentially its cousins. They compiled


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6,594


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solar twins, which is a staggering


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number when you think about how special


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we tend to think our sun is. And they


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used ISA's Gaia satellite data to


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determine two things about each star.


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How old it is and where it has been


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moving. What they found was a striking


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pattern. A large number of these solar


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twins are between 4 and 6 billion years


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old, which is the same age bracket as


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our own son. That clustering is not


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random. It suggests that the sun and


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many of these stars formed in the same


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general region of the galaxy, probably


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closer to the Milky Way's inner regions


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and then gradually drifted outward


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together over billions of years. But


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here's the puzzle that the researchers


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had to solve. The Milky Way has what's


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called a galactic bar, a rotating


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bar-shaped structure of stars and gas


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near the center. That bar creates


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something astronomers call a co-rotation


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barrier, which basically traps stars in


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certain orbital zones and makes it very


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hard for them to move outward.


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>> So, how did the sun escape?


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>> The theory is that when the sun and its


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companions formed, the galactic bar was


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still in the process of forming. It


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wasn't fully developed yet, and the


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weaker barrier may have allowed whole


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groups of stars to break out together,


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carried along by the dynamics of the


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early galaxy. And the implications of


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this go beyond just knowing our sun's


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origin story. If the sun formed much


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closer to the center, researchers


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estimate about 10,000 lighty years


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closer than it is today, then this


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migration may actually be part of the


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reason Earth became habitable. The


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galactic center is a harsher place.


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Higher star density, more frequent


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supernova explosions, more high energy


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radiation. Moving outward placed us in a


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calmer neighborhood, one where complex


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chemistry and life could hold and


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persist over billions of years.


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>> So, our sun didn't travel alone. It was


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part of a wave, a kind of ancient


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stellar migration. And that journey may


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be one of the reasons we are here to


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talk about it.


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>> There is a lot to be grateful for in


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that story. If you've been following the


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global moon race, you'll know that China


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has an ambitious target to land


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astronauts on the lunar surface by 2030.


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And this week, we got the clearest


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picture yet of where that landing might


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happen. A new study published in Nature


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Astronomy has highlighted a region


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called Remi Bode, a volcanic area near


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the lunar equator on the moon's near


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side as the leading candidate for


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China's first crude lunar mission. And


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the description that researcher Jun Hong


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from the China University of


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Geossciences used for it is just


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perfect. He called it a geological


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museum


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>> because within a relatively compact


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area, Reay Bode contains five distinct


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terrain types. ancient pyrolastic


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deposits from volcanic eruptions, smooth


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mare basults, two different rail systems


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which are essentially long channels or


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cracks in the surface and nearby


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highland material. Five completely


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different chapters of lunar history, all


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accessible from one landing zone. That's


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the key point for mission planners. A


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scientifically rich site is only useful


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if it's also safe and practical. And


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what makes Remay Bode attractive is that


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astronauts could potentially traverse


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across several very different geological


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environments without having to travel


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enormous and risky distances.


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>> The researchers dated some of the


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earliest volcanic activity in the region


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to roughly 3.2 to 3.7 billion years ago.


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That's deep lunar history. And those


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ancient pyrolastic materials could


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include ash and glass beads thrown up


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from the moon's interior, which would be


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completely different from the rocks


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returned by the Apollo missions or


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China's own robotic Chang missions. This


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site didn't come out of nowhere. Chinese


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researchers had originally screened 106


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potential landing areas and narrowed


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them to 14 candidates based on practical


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requirements. nearside location for


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communication with Earth, access to


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solar power, and terrain safe enough for


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landing and surface operations. From


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that short list, the new paper proposes


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four specific landing spots within ReMay


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Boat itself, each offering slightly


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different scientific priorities while


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still meeting those safety criteria. The


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plan also includes the use of an


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unpressurized rover to travel between


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geological units which would


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dramatically extend the science possible


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in a single mission. China's crude lunar


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program is part of a larger sequence


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that includes Chong A 7 and Chong A


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missions with long-term goals around a


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south pole research station. But Reay


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Bode as a first landing site makes a lot


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of sense. near side for communications,


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scientifically diverse, and a manageable


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operating environment.


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>> It's still a candidate rather than a


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confirmed destination, but this is the


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most specific and scientifically


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detailed case we've seen yet for where


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China's first astronauts might set foot


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on another world.


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>> Another country making a big


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announcement this week. Russia has


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announced plans to launch a mission


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called Vanera D to Venus in 2036. And


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it's an ambitious one. We're talking


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about a lander, a balloon that would


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float through the Venucian atmosphere,


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and an orbiter all working together.


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>> And the historical context here is


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remarkable. The Soviet Union is the only


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nation in history to have successfully


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landed and operated spacecraft on the


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surface of Venus. Vanera 7 did it first


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back in 1970. And over the following 13


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years, the Soviets sent a whole series


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of Vanera landers and orbiters, 16


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missions in total across 22 years. And


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when you understand what the surface of


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Venus is actually like, that achievement


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becomes even more extraordinary. Surface


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temperatures around 900° F. That's 480


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C. atmospheric pressure more than 90


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times that of Earth at sea level. It is


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a genuinely hellish environment.


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>> The Soviet Vanera landers didn't just


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survive. They sent back images. Those


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photographs of Venus's volcanic rock


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surface tinged yellow by the sulfuric


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acid clouds above remain some of the


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most extraordinary images in the history


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of space exploration.


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>> Russia hasn't been to Venus since 1983.


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And Vanera D has actually been in


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planning since 2003. It was at one point


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even under consideration as a joint


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mission with NASA before Russia's 2022


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invasion of Ukraine ended that kind of


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collaboration.


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>> Russia's first deputy prime minister


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Dennis Mterov confirmed the mission this


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week, describing Venus alongside the


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moon as central to Russia space


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ambitions. And one of the Nerad's key


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scientific goals will be searching for


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signs of microbial life in Venus's


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clouds.


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>> That's not as outlandish as it might


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sound. The cloud layers of Venus at


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altitudes of around 48 to 60 km have


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temperatures and pressures not unlike


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those at Earth's surface. And there have


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been disputed detections of phosphine


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and ammonia there, both of which could


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potentially be biological in origin.


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Russia isn't the only nation looking at


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Venus right now.Sa's Envision mission,


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India's Shukrion 1, and NASA's Da Vinci


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and Veraritoss projects are all in


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various stages of development. Venus is


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having a moment.


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>> And if Fener D launches in 2036 as


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planned, it would extend one of the most


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impressive and now largely forgotten


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legacies in space exploration history.


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The Soviets conquered Venus. Russia


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wants to go back. Now, here's a


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milestone that deserves a moment of


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appreciation. This week, engineers at


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the John's Hopkins Applied Physics


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Laboratory in Maryland officially began


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assembling NASA's Dragonfly rotorcraft,


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the nuclearpowered drone that will one


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day fly across the surface of Saturn's


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moon Titan. This is the point where a


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mission stops being a plan and starts


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being a physical thing. Principal


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investigator Elizabeth Turtle put it


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perfectly when she said, "This milestone


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essentially marks the birth of our


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flight system."


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>> So, what is Dragonfly exactly? It's a


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car-sized eight rotor drone. Think of a


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very large quadcopter, but with eight


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rotors and four counterrotating pairs.


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It'll be powered not by solar energy,


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but by a radioisotope thermo electric


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generator, a nuclear power source.


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Because sunlight on Titan is too faint


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and too inconsistent to be useful.


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>> And Titan is just a spectacular target.


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It's Saturn's largest moon, and it's


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unlike anywhere else we've thought about


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sending a mission. It has a thick


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nitrogen atmosphere, denser than


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Earth's, which is actually what makes


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flying there possible. It has rivers and


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lakes, but not of water, of liquid


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methane and ethn. It has complex organic


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chemistry raining down from the


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atmosphere like a slow chemical snow.


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>> Scientists think Titan's surface


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chemistry might resemble what Earth


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looked like before life emerged, which


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is exactly why it's so exciting from an


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astrobiology perspective. Dragonfly will


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fly to dozens of locations across the


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surface, stopping to collect and analyze


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samples as it goes. The first power and


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functional tests have already been


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completed on Dragonflyy's integrated


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electronics module, its brain, and its


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power switching units. The aeros shell


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and cruise stage are being assembled at


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Lockheed Martin in Colorado, and the


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wind tunnel testing at NASA Langley has


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already validated the rotor design.


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>> The timeline integration and testing


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continues at John's Hopkins through this


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year and into early 2027. Then system


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level testing at Loheed Martin. Then


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final environmental testing back at


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Hopkins before heading to Kennedy Space


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Center in spring of 2028 for launch on a


00:11:57.760 --> 00:12:00.790
SpaceX Falcon Heavy that summer. Arrival


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at Titan 2034. And once there, Dragonfly


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aims to cover more than 108 miles of


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terrain, nearly double the total


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distance traveled by all Mars rovers


00:12:12.800 --> 00:12:15.030
combined. It is one of the most


00:12:15.040 --> 00:12:17.509
audacious planetary missions ever


00:12:17.519 --> 00:12:20.550
conceived and this week it became a real


00:12:20.560 --> 00:12:21.829
spacecraft.


00:12:21.839 --> 00:12:24.550
>> More news from China. The race to return


00:12:24.560 --> 00:12:27.190
samples from Mars is very much on and


00:12:27.200 --> 00:12:29.509
this week came confirmation that China's


00:12:29.519 --> 00:12:31.269
entry in that race is moving from


00:12:31.279 --> 00:12:33.670
engineering prototypes to real flight


00:12:33.680 --> 00:12:36.629
hardware. Chief designer Leu Ji Chong


00:12:36.639 --> 00:12:39.030
announced at China's annual two sessions


00:12:39.040 --> 00:12:41.350
political meetings on March 12th that


00:12:41.360 --> 00:12:43.990
Tanwin 3 has achieved breakthroughs in


00:12:44.000 --> 00:12:46.550
all key technologies and now is entering


00:12:46.560 --> 00:12:48.629
the flight model development phase,


00:12:48.639 --> 00:12:50.550
meaning they're building the actual


00:12:50.560 --> 00:12:52.870
spacecraft that will go to Mars.


00:12:52.880 --> 00:12:56.629
>> Gon 3 is an enormously complex mission.


00:12:56.639 --> 00:12:58.710
It involves two separate launches from


00:12:58.720 --> 00:13:02.230
Earth in late 2028 using Long March 5


00:13:02.240 --> 00:13:04.230
rockets, the same type that launched


00:13:04.240 --> 00:13:06.389
China's previous Mars mission and its


00:13:06.399 --> 00:13:09.350
lunar sample return. One launch carries


00:13:09.360 --> 00:13:11.990
a lander and ascent vehicle. The other


00:13:12.000 --> 00:13:14.230
carries an orbiter and Earth return


00:13:14.240 --> 00:13:16.949
spacecraft. The lander touches down on


00:13:16.959 --> 00:13:20.150
Mars, collects at least 500 g of Martian


00:13:20.160 --> 00:13:22.310
rock and soil using a combination of a


00:13:22.320 --> 00:13:25.190
scoop, a drill, and a small drone. Then


00:13:25.200 --> 00:13:26.870
the ascent vehicle launches those


00:13:26.880 --> 00:13:29.350
samples into Mars orbit. There it


00:13:29.360 --> 00:13:31.509
rendevous with the orbiter which then


00:13:31.519 --> 00:13:33.350
carries the samples all the way back to


00:13:33.360 --> 00:13:36.710
Earth targeted arrival in 2031.


00:13:36.720 --> 00:13:39.509
>> If successful that would make Tanwen 3


00:13:39.519 --> 00:13:42.150
the first ever mission to return samples


00:13:42.160 --> 00:13:45.190
from Mars and that's important context.


00:13:45.200 --> 00:13:47.750
NASA's own Mars sample return program


00:13:47.760 --> 00:13:49.910
was effectively cancelled earlier this


00:13:49.920 --> 00:13:52.710
year when it received no funding in the


00:13:52.720 --> 00:13:55.990
2026 appropriations bill. China has


00:13:56.000 --> 00:13:57.750
narrowed its landing site candidates


00:13:57.760 --> 00:14:01.189
from 106 down to 19 with the final three


00:14:01.199 --> 00:14:03.430
to be selected by the end of this year.


00:14:03.440 --> 00:14:05.030
Candidate sites include ancient


00:14:05.040 --> 00:14:07.189
shorelines, clay, mineralrich terrain


00:14:07.199 --> 00:14:09.430
that could preserve organic molecules,


00:14:09.440 --> 00:14:11.829
and areas associated with Mars's ancient


00:14:11.839 --> 00:14:14.470
water systems. The primary scientific


00:14:14.480 --> 00:14:17.110
goal is the search for bio signatures,


00:14:17.120 --> 00:14:19.350
potential signs that life once existed


00:14:19.360 --> 00:14:22.150
on Mars. The mission is also open to


00:14:22.160 --> 00:14:24.310
international collaboration with China


00:14:24.320 --> 00:14:26.629
inviting partner payloads and promising


00:14:26.639 --> 00:14:29.110
international scientists access to the


00:14:29.120 --> 00:14:32.069
returned samples. This is a story worth


00:14:32.079 --> 00:14:34.310
watching very closely. By the time


00:14:34.320 --> 00:14:37.670
Tanwan 3 launches in 2028, it may well


00:14:37.680 --> 00:14:40.150
be the only active Mars sample return


00:14:40.160 --> 00:14:42.470
mission on the books. The first Martian


00:14:42.480 --> 00:14:44.710
soil in a laboratory on Earth could be


00:14:44.720 --> 00:14:47.350
arriving on a Chinese spacecraft.


00:14:47.360 --> 00:14:48.949
>> We'll keep an eye on this one. The


00:14:48.959 --> 00:14:51.269
geopolitical ramifications, not to


00:14:51.279 --> 00:14:53.350
mention bragging rights, could be quite


00:14:53.360 --> 00:14:54.310
important.


00:14:54.320 --> 00:14:56.790
>> All right, we saved the best for Pi Day.


00:14:56.800 --> 00:14:59.030
And NASA's astronomy picture of the day


00:14:59.040 --> 00:15:01.189
team clearly agrees with us because


00:15:01.199 --> 00:15:04.470
today's APOD is dedicated entirely to K2


00:15:04.480 --> 00:15:07.509
315b, the exoplanet with a year that


00:15:07.519 --> 00:15:12.870
lasts almost exactly 3.14 days. K2315b


00:15:12.880 --> 00:15:14.629
was discovered using data from the


00:15:14.639 --> 00:15:17.110
Kepler space telescope's extended K2


00:15:17.120 --> 00:15:20.230
mission and announced back in 2020. It's


00:15:20.240 --> 00:15:23.030
an Earth-sized world orbiting a cool red


00:15:23.040 --> 00:15:26.790
dwarf star, an Mtype star about 185


00:15:26.800 --> 00:15:29.030
light years away from us. Now, an


00:15:29.040 --> 00:15:32.389
orbital period of 3.14 days means it is


00:15:32.399 --> 00:15:35.030
very close to its star, very close,


00:15:35.040 --> 00:15:37.030
which means its surface temperature is


00:15:37.040 --> 00:15:39.990
absolutely scorching. the kind of baking


00:15:40.000 --> 00:15:41.509
hot that makes any thoughts of


00:15:41.519 --> 00:15:44.150
habitability evaporate immediately.


00:15:44.160 --> 00:15:46.790
>> But that's fine. K2315b


00:15:46.800 --> 00:15:48.870
is not here to be habitable. It's here


00:15:48.880 --> 00:15:51.110
to be delightful because of all the


00:15:51.120 --> 00:15:53.509
exoplanets we found, and we found


00:15:53.519 --> 00:15:55.990
thousands. Now, this one just happens to


00:15:56.000 --> 00:15:58.790
orbit its star in almost precisely pi


00:15:58.800 --> 00:15:59.509
days.


00:15:59.519 --> 00:16:02.150
>> The precision is genuinely striking.


00:16:02.160 --> 00:16:04.150
Astronomers measured the orbital period


00:16:04.160 --> 00:16:06.629
at 3.14159


00:16:06.639 --> 00:16:08.710
days, which if you've had your pi


00:16:08.720 --> 00:16:10.870
memorized since school, you'll recognize


00:16:10.880 --> 00:16:13.990
as pi to five decimal places. The


00:16:14.000 --> 00:16:16.069
universe didn't do that on purpose,


00:16:16.079 --> 00:16:17.829
obviously. But it's a beautiful


00:16:17.839 --> 00:16:19.749
coincidence and a wonderful reminder


00:16:19.759 --> 00:16:21.829
that the cosmos doesn't always have to


00:16:21.839 --> 00:16:24.550
be profound and weighty. Sometimes it


00:16:24.560 --> 00:16:26.310
just gives you a planet that celebrates


00:16:26.320 --> 00:16:27.670
mathematics.


00:16:27.680 --> 00:16:29.749
>> So, from all of us here at Astronomy


00:16:29.759 --> 00:16:32.389
Daily, happy Pi Day. May your circles be


00:16:32.399 --> 00:16:34.069
perfect and your exoplanets be


00:16:34.079 --> 00:16:35.910
numerically satisfying.


00:16:35.920 --> 00:16:38.629
>> And that wraps up episode 63 of


00:16:38.639 --> 00:16:41.269
Astronomy Daily Season 5. What a show


00:16:41.279 --> 00:16:43.990
today. Solar twin migrations, China's


00:16:44.000 --> 00:16:46.629
lunar museum, Soviet era Venus


00:16:46.639 --> 00:16:49.749
nostalgia, nuclear drones for Titan, the


00:16:49.759 --> 00:16:52.629
Mars sample race, and the Pi Day cosmic


00:16:52.639 --> 00:16:53.350
treat.


00:16:53.360 --> 00:16:55.269
>> If you enjoyed today's episode, please


00:16:55.279 --> 00:16:57.110
leave us a review wherever you listen.


00:16:57.120 --> 00:16:58.710
It genuinely makes a difference in


00:16:58.720 --> 00:17:01.110
helping new listeners find us. And share


00:17:01.120 --> 00:17:02.949
the show with anyone who needs a little


00:17:02.959 --> 00:17:04.710
more space in their life.


00:17:04.720 --> 00:17:07.909
>> You can find us at astronomyaily.io


00:17:07.919 --> 00:17:10.549
and we're at Astro Daily Pod on X,


00:17:10.559 --> 00:17:13.270
Instagram, Tik Tok, YouTube, Facebook,


00:17:13.280 --> 00:17:15.750
and Tumblr. All your show notes, links,


00:17:15.760 --> 00:17:17.669
and extras are on the website.


00:17:17.679 --> 00:17:19.990
>> We'll be back on Monday with more of the


00:17:20.000 --> 00:17:22.949
universe's greatest hits. Until then,


00:17:22.959 --> 00:17:26.789
keep looking up.


00:17:26.799 --> 00:17:35.029
The stories been told.


00:17:35.039 --> 00:17:38.760
Stories told.