MAVEN’s Silence: Unravelling the Mystery of Mars’ Lost Contact

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Language: en

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This is Spacetime series 28, episode 147


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for broadcast on the 15th of December,


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2025.


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Coming up on Spaceime, NASA loses


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contact with its maven Mars Orbiter. How


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the cosmic landscape impacts the


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galaxy's life cycle, and a new study


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suggests the planets Uranus and Neptune


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might be rock giants rather than ice


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giants. All that and more coming up on


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Spaceime.


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Welcome to Space Time with Stuart Garry.


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NASA has lost contact with its Mars


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Atmosphere and Volatile Evolution or


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Maven spacecraft. The agency says the


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probe disappeared off the proverbial


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screens on December the 6th. At the


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time, telemetry showed Maven was working


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nominally as it passed behind Mars as


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seen from Earth, but the spacecraft


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didn't resume communications after


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emerging from behind the planet. Mission


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managers are now investigating the


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anomaly and are yet to determine what's


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gone wrong. The orbit has been circling


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the red planet for more than a decade,


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gathering scientific data and serving as


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a key communications relay satellite.


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Maven launched back in November 2013 and


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entered orbit around Mars in September


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2014. The spacecraft's primary mission


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has been to study the planet's upper


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atmosphere and interactions with the


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solar wind, including how the atmosphere


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escapes into space, helping scientists


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better understand how the red planet


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changed from a warm, wet world with a


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thick atmosphere, one capable of


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supporting liquid water on its surface


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and turning it into the inhospitable,


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freeze-dried desert it is today. This


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report from NASA TV. Today, Mars is a


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cold, dry world with a tenuous


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atmosphere only 1% as thick as Earth's.


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But in the ancient past, water flowed


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freely across the Martian surface,


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maintained by a thick, early atmosphere.


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Since it first arrived at the red planet


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in September 2014, NASA's Maven


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spacecraft has been studying how that


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atmosphere was lost to space and with


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it, the water.


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In 2015, Maven observed the solar wind


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eroding the Martian atmosphere. The


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solar wind is a stream of electrically


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charged particles blowing from the sun.


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Maven watched as ions from the Mars


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upper atmosphere were accelerated by the


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solar winds magnetic field and driven


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into space, confirming that this process


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has deeply eroded the Martian


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atmosphere.


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In 2017, Maven showed that a process


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called sputtering has had an even


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greater effect on the atmosphere. When


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ions from Mars get picked up by the


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solar winds magnetic field, they can


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crash into neutral atoms at the top of


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the atmosphere, sputtering them into


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space. Maven measured present-day


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isotopes of argon, which can be removed


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only by sputtering, to determine that


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65% of the noble gas has been lost over


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time. This allowed scientists to


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estimate the escape of other gases, and


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determine that sputtering has been the


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primary mechanism driving the atmosphere


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into space. Later in 2017, Maven


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revealed a twist in Mars' invisible


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magnetic tail. When the sun's magnetic


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fields reach Mars, they pile up and wrap


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around the planet, creating an induced


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magnetic field that is drawn out behind


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Mars like a comet's tail. The Martian


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crust also contains small pockets of its


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own early magnetic field, which rotate


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along with the planet. Maven discovered


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that when these two fields interact,


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they put a twist in the magneto tail,


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confirming model predictions.


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In 2018, a runaway series of dust storms


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created a dust cloud so large that it


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enveloped the planet. During this global


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dust storm, Maven observed an abrupt


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unexpected spike in the amount of water


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in the upper atmosphere. It discovered


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that heating from dust storms can loft


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water molecules far higher into the


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atmosphere than usual, leading to a


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sudden surge in water lost to space.


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Later in 2018, Maven announced the


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discovery of a new type of aurora at


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Mars. The mission had previously


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observed auroras during solar storms


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after electrons from the sun struck the


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upper atmosphere, causing it to glow


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with ultraviolet light. Maven's 2018


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discovery was the first observation of a


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Mars proton aurora. When protons from


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the solar wind pick up electrons from


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the Martian ionosphere, they can slip


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through the planet's bow shock and


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plunge into its upper atmosphere,


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causing widespread auroras. On Earth,


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proton auroras are isolated near the


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poles, but on Mars, they can bathe the


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dayside in ultraviolet radiation.


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In 2019, Maven produced the first map of


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wind currents in the Martian


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thermosphere, revealing disturbances and


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high altitude winds caused by terrain


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features on the surface. Maven sensed


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these disturbances as it skimmed through


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the upper atmosphere, feeling the


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imprint of mountains and valleys far


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below.


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In 2020, data for Maven led to the


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creation of another new map showing the


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Martian atmosphere's electric current


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systems for the first time. Maven


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detected these currents indirectly by


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observing the solar winds magnetic field


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lines drape around the planet. Mapping


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the electric current systems can help


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scientists to better understand the


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forces that drive atmospheric escape.


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In 2022, Maven watched as the solar wind


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unexpectedly disappeared from Mars. The


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event occurred when a fastmoving patch


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of the solar wind overtook a slower


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moving region, leaving a void in its


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wake. In response, the Martian


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magnetosphere ballooned outward by


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thousands of kilome, engulfing Maven's


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orbit and causing the solar wind to


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temporarily disappear from view. In 2022


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and 2023, Maven captured stunning


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ultraviolet images of Mars when the


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planet was near opposite ends of its


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elliptical orbit. The first image was


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taken when the southern hemisphere was


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in summer, which coincides with Mars's


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closest approach to the sun. Canyons and


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basins are covered with a thin haze of


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ozone indicated by a tinge of pink. The


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second image was taken during northern


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spring after Mars had passed its


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furthest point from the sun. White


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clouds hint at rapidly changing


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conditions in the northern polar regions


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while deep magenta signals a buildup of


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ozone during the frigid winter.


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In 2024, Maven observed the aftermath of


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an ex-class solar flare, the strongest


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type of eruption from the sun. The flare


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was quickly followed by a burst of


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charged particles crashing into Mars,


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leaving black and white streaks on


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images taken by NASA's Curiosity rover.


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Maven watched from above as auroras lit


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up the planet in a brilliant display of


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celestial fireworks.


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Maven's other role as a communications


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relay satellite has provided a key link


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between both the Mars Curiosity and Mars


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Perseverance rovers down on the Martian


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surface and mission managers at the Jet


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Propulsion Laboratory in Pasadena,


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California by way of NASA's Deep Space


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Communications Network ground stations


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in Goldstone, California, Madrid, Spain,


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and Camber, Australia. NASA's Mars


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Odyssey spacecraft and Mars


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Reconnaissance Orbiter also serve as


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communications relays for the rovers,


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but both are significantly older than


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Maven. And this isn't the first time


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that Maven has suffered technical


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issues. Back in 2022, the prob's


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inertial measurement units, which are


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used for navigation, failed. That force


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mission manages to switch the orbiter to


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a stellar navigation system, minimizing


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reliance on the inertial measurement


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units. Maven has enough propellant to


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maintain its orbit through at least


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until the end of the decade.


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This is spaceime still to come. How a


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cosmic landscape can impact the galaxy's


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life cycle. And a new study suggests the


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solar systems two ice giants, Uranus and


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Neptune, might actually be more rocky


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than icy. All that and more still to


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come on Spaceime.


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A new study has shown how a galaxy's


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neighborhood can influence its


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evolution. The findings reported in the


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monthly notices of the Royal


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Astronomical Society offers a new level


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of detail into science's understanding


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of galactic evolution in the distant


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universe. The research is based on data


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from Devils, the Deep Extragalactic


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Visible Legacy Survey, an extensive


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galaxy evolution survey which shows that


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a galaxy's local environment plays a


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major role in how it changes over time,


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strongly influencing its shape, size,


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and even its growth rate. The survey


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combines data from a wide range of


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terrestrial and space-based telescopes


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to investigate various aspects of


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astrophysics for analyzing hundreds of


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thousands of galaxies. The project lead,


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Luke Davies, from the University of


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Western Australia, node of the


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International Center for Radioastronomy


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Research, says the Devil Survey is


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unique in that it's the first of its


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kind to explore detailed aspects of the


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distant universe. It focuses on galaxies


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that existed up to 5 billion years ago


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and examines how these galaxies have


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changed through to the present day. He


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says, "While previous surveys during


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this period of universal history have


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explored the broad evolution of galaxy


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properties, they've inherently lacked


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the capacity to determine the finer


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details of the cosmic landscape. The


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Devil Survey has allowed astronomers to


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zoom in and focus on mapping out the


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small scale environment of galaxies.


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This new approach has allowed Davies and


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colleagues to identify the number of


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stars in a galaxy, understand ongoing


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star formation, and analyze their visual


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appearance, shapes, and structures. They


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can then compare these properties


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between galaxies in the present day


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universe with galaxies that existed


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around 5 billion years ago. In order to


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determine how galaxies have changed over


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time, they found that galaxies that are


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surrounded by lots of other galaxies,


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one might say the bustling centers of


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galactic cities in the cosmos tend to


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grow more slowly and have different


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structures compared to their more


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isolated counterparts. In crowded


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regions of the universe, galaxies


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interact with each other and compete for


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resources such as gas to form new stars


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and grow. Davy says this competition can


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impact their evolution and in some


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instances cause star formation to slow


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down earlier than expected causing


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galaxies to die.


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>> It's a survey that's primarily based


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around observations which are done with


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the Anglo Australian telescope in New


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South Wales. So what we do is we pick a


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few patches of the night sky and we take


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a lot of imaging data that currently


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exists in those regions and we put it


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together to build a sample of galaxies


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that we want to explore. And then we go


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to the Anglo Australian telescope and we


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measure spectra for all of those


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galaxies. And what that primarily allows


00:11:23.519 --> 00:11:25.910
us to do is to measure the


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three-dimensional structure of the


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universe. So we map out the distances


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and the positions of all of the


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galaxies. And then we determine what the


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structure looks like. And we use that


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structure to work out places in the


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universe where there are lots of


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galaxies. So very sort of overdense


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regions which are your sort of bustling


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city centers of of the universe


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environment. So they're mostly galaxy


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groups which are slightly smaller than


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clusters. So given the volume Yeah.


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Yeah. So sort of from the local group


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size up to a little bit bigger mainly


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because of the volumes that we probe are


00:11:54.320 --> 00:11:56.389
quite small in comparison to the nearby


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universe. So you actually don't get some


00:11:58.240 --> 00:12:00.550
of the really massive cluster type


00:12:00.560 --> 00:12:02.470
things. Then what we do is we try and


00:12:02.480 --> 00:12:04.230
combine all the information about what


00:12:04.240 --> 00:12:06.629
the galaxy's local environment is like.


00:12:06.639 --> 00:12:08.470
So how how clustered the regions are and


00:12:08.480 --> 00:12:09.990
link that up with the properties of the


00:12:10.000 --> 00:12:12.870
galaxies to see how where they live is


00:12:12.880 --> 00:12:14.629
impacting their life cycle.


00:12:14.639 --> 00:12:15.829
>> And what have you found?


00:12:15.839 --> 00:12:17.910
>> What we found is that when you start to


00:12:17.920 --> 00:12:20.310
to map out the universe on this sort of


00:12:20.320 --> 00:12:21.990
smallalish scale in terms of


00:12:22.000 --> 00:12:23.430
environments that the properties of


00:12:23.440 --> 00:12:25.750
galaxies are very strongly linked to


00:12:25.760 --> 00:12:27.430
where they live in the universe. So if


00:12:27.440 --> 00:12:29.590
you grow up in bustling sort of city


00:12:29.600 --> 00:12:31.269
centers of the the the galactic


00:12:31.279 --> 00:12:32.949
environment. You actually die more


00:12:32.959 --> 00:12:35.509
easily. Um you form less stars. you you


00:12:35.519 --> 00:12:37.350
look different. You grow in a different


00:12:37.360 --> 00:12:39.750
way to if you live in a sort of isolated


00:12:39.760 --> 00:12:41.030
remote region of space.


00:12:41.040 --> 00:12:42.389
>> I would have thought that if you're in a


00:12:42.399 --> 00:12:44.949
busy bustling area with lots of other


00:12:44.959 --> 00:12:46.949
galaxies, it'd be easier to steal gas


00:12:46.959 --> 00:12:49.110
from them and make more stars and even


00:12:49.120 --> 00:12:51.269
grow bigger because you can merge with


00:12:51.279 --> 00:12:52.949
them. That's not what you found. But


00:12:52.959 --> 00:12:55.350
>> so so that's largely true for the the


00:12:55.360 --> 00:12:57.590
sort of big central galaxies in those


00:12:57.600 --> 00:12:59.590
environments. We tend to split galaxies


00:12:59.600 --> 00:13:01.269
in those environments to centrals and


00:13:01.279 --> 00:13:03.030
satellites where central is sort of the


00:13:03.040 --> 00:13:04.790
main big galaxy in the middle and the


00:13:04.800 --> 00:13:06.389
satellites are all the other ones which


00:13:06.399 --> 00:13:08.389
are moving moving around it. So for the


00:13:08.399 --> 00:13:10.230
central region being in that over dense


00:13:10.240 --> 00:13:11.829
environment actually helps it to grow


00:13:11.839 --> 00:13:13.829
more massive but for the satellites it


00:13:13.839 --> 00:13:15.430
actually stops them from forming new


00:13:15.440 --> 00:13:17.750
stars so that they don't grow any bigger


00:13:17.760 --> 00:13:19.990
and all of those interactions with the


00:13:20.000 --> 00:13:21.590
other galaxies actually change the way


00:13:21.600 --> 00:13:24.310
the galaxy looks as well. So, we define


00:13:24.320 --> 00:13:25.670
how a galaxy looks at something called


00:13:25.680 --> 00:13:27.350
morphology, which basically defines


00:13:27.360 --> 00:13:29.670
whether it's sort of a big blobby red


00:13:29.680 --> 00:13:31.670
structure or a disc-like spiral


00:13:31.680 --> 00:13:33.670
structure. And where a galaxy lives in


00:13:33.680 --> 00:13:35.110
its environment and its interactions


00:13:35.120 --> 00:13:37.190
with other galaxies changes the type of


00:13:37.200 --> 00:13:38.949
morphology that that galaxy is.


00:13:38.959 --> 00:13:41.269
>> Is that why the large and small melanic


00:13:41.279 --> 00:13:43.670
clouds are disrupted spirals or


00:13:43.680 --> 00:13:45.670
irregular spirals rather than grand


00:13:45.680 --> 00:13:47.750
spirals like say the Milky Way or


00:13:47.760 --> 00:13:49.910
>> Yeah. So, they're also much smaller. So


00:13:49.920 --> 00:13:51.590
these sort of smaller regular galaxies


00:13:51.600 --> 00:13:53.430
tend to form as more sort of blobby


00:13:53.440 --> 00:13:54.870
structures but yeah their interactions


00:13:54.880 --> 00:13:56.550
with the Milky Way will make them look


00:13:56.560 --> 00:13:58.150
different. So imagine if you have like


00:13:58.160 --> 00:14:00.150
say you have two big spiralally type


00:14:00.160 --> 00:14:01.590
galaxies and you smash them both


00:14:01.600 --> 00:14:03.030
together you end up with something that


00:14:03.040 --> 00:14:04.949
looks more like an elliptical galaxy and


00:14:04.959 --> 00:14:06.870
because those processes are happening


00:14:06.880 --> 00:14:08.870
more readily in group environments you


00:14:08.880 --> 00:14:10.870
end up getting more elliptical like


00:14:10.880 --> 00:14:12.389
things in group environments than you


00:14:12.399 --> 00:14:14.629
would in isolated environments. The real


00:14:14.639 --> 00:14:16.230
benefit of what we've done with devils


00:14:16.240 --> 00:14:18.230
in this is that this type of science of


00:14:18.240 --> 00:14:20.470
mapping out the sort of group scale, so


00:14:20.480 --> 00:14:22.150
the the much lower mass scale than


00:14:22.160 --> 00:14:23.829
clusters environments has only


00:14:23.839 --> 00:14:25.509
previously been done in the relatively


00:14:25.519 --> 00:14:27.269
local universe. The reason for this is


00:14:27.279 --> 00:14:28.949
that to be able to map out the


00:14:28.959 --> 00:14:30.230
three-dimensional structure of a


00:14:30.240 --> 00:14:32.150
universe, you need to measure red shifts


00:14:32.160 --> 00:14:33.750
basically for lots of galaxies to get to


00:14:33.760 --> 00:14:35.269
their distance. And doing that outside


00:14:35.279 --> 00:14:36.790
of the local universe is really


00:14:36.800 --> 00:14:38.550
problematic because you have to observe


00:14:38.560 --> 00:14:40.230
for a really long time to get enough


00:14:40.240 --> 00:14:41.829
signal to noise to measure the red


00:14:41.839 --> 00:14:43.269
shift. So we've done this in the local


00:14:43.279 --> 00:14:44.949
universe with other surveys, but with


00:14:44.959 --> 00:14:46.310
Devils, what we've done is we've


00:14:46.320 --> 00:14:47.990
stretched that out into the much more


00:14:48.000 --> 00:14:49.750
distant universe by observing the same


00:14:49.760 --> 00:14:51.990
galaxy for much longer time basically to


00:14:52.000 --> 00:14:53.350
get their red shift. So it's the first


00:14:53.360 --> 00:14:54.949
time we've really managed to map out


00:14:54.959 --> 00:14:56.870
this sort of group scale structure in


00:14:56.880 --> 00:14:58.230
the very distant universe


00:14:58.240 --> 00:15:00.550
>> and you're moving from devils to waves


00:15:00.560 --> 00:15:01.189
next.


00:15:01.199 --> 00:15:03.509
>> Yeah. So waves is a survey that going to


00:15:03.519 --> 00:15:05.910
be starting next year on a on a new


00:15:05.920 --> 00:15:07.750
facility which is called foremost which


00:15:07.760 --> 00:15:09.990
is the 4 m multiobject spectrograph


00:15:10.000 --> 00:15:11.910
telescope which is in Chile. And what


00:15:11.920 --> 00:15:13.350
we're doing with waves is that we


00:15:13.360 --> 00:15:15.110
actually have a few different sort of


00:15:15.120 --> 00:15:16.629
surveys that we're doing but one of the


00:15:16.639 --> 00:15:18.069
components of waves which is called


00:15:18.079 --> 00:15:19.670
waves deep. It's basically the same as


00:15:19.680 --> 00:15:22.230
devils but over a much much larger area.


00:15:22.240 --> 00:15:23.750
So essentially we'll be doing all of the


00:15:23.760 --> 00:15:25.350
science that we can do with devils now


00:15:25.360 --> 00:15:27.269
but to a much much finer degree over


00:15:27.279 --> 00:15:29.670
much larger volumes of the universe. We


00:15:29.680 --> 00:15:31.829
actually um have got the first test


00:15:31.839 --> 00:15:33.829
observations from foremost for some of


00:15:33.839 --> 00:15:35.189
the galaxies in waves which has been


00:15:35.199 --> 00:15:36.470
really exciting. So, we've all been


00:15:36.480 --> 00:15:37.990
working away to try and understand


00:15:38.000 --> 00:15:39.110
everything that's going on with the


00:15:39.120 --> 00:15:40.710
telescope and then we'll start waves in


00:15:40.720 --> 00:15:41.590
Earth next year.


00:15:41.600 --> 00:15:44.389
>> One of the big topics of recent papers


00:15:44.399 --> 00:15:46.949
that I've seen has been this ongoing


00:15:46.959 --> 00:15:50.069
hypothesis that the Milky Way may not be


00:15:50.079 --> 00:15:53.350
within a a strand of galaxies in the


00:15:53.360 --> 00:15:55.990
cosmic web of the universe, but rather


00:15:56.000 --> 00:15:58.310
it may actually be at or near the edge


00:15:58.320 --> 00:16:00.790
of a large void. Has your work in any


00:16:00.800 --> 00:16:02.790
way at all helped resolve that issue?


00:16:02.800 --> 00:16:05.030
The issue of this is is that some of our


00:16:05.040 --> 00:16:08.069
our results in terms of our cosmological


00:16:08.079 --> 00:16:10.230
analyses, so analyses of how the whole


00:16:10.240 --> 00:16:11.990
universe works essentially and how the


00:16:12.000 --> 00:16:13.590
whole universe is evolving are a little


00:16:13.600 --> 00:16:15.189
bit in tension with each other. And one


00:16:15.199 --> 00:16:16.949
of the possible solutions for that is


00:16:16.959 --> 00:16:19.269
that we live in a slightly atypical part


00:16:19.279 --> 00:16:21.269
of the universe. So next to a cosmic


00:16:21.279 --> 00:16:22.629
void which would mean that some of our


00:16:22.639 --> 00:16:24.710
our measurements that we use to infer


00:16:24.720 --> 00:16:26.629
cosmological principles are a little bit


00:16:26.639 --> 00:16:28.949
wrong because all of those assume


00:16:28.959 --> 00:16:30.710
basically that we live in a very


00:16:30.720 --> 00:16:32.629
representative place in the universe.


00:16:32.639 --> 00:16:34.870
Now it is really super interesting but


00:16:34.880 --> 00:16:36.550
it's not really something that I I work


00:16:36.560 --> 00:16:38.710
on massively. I look at galaxies which


00:16:38.720 --> 00:16:40.389
are much much further away than that


00:16:40.399 --> 00:16:41.990
local volume. But there is an


00:16:42.000 --> 00:16:43.990
Australian-led survey that's going to be


00:16:44.000 --> 00:16:45.910
happening on for almost as well called


00:16:45.920 --> 00:16:48.150
the 4HS which is being run from the


00:16:48.160 --> 00:16:49.590
country which will actually test some of


00:16:49.600 --> 00:16:50.949
these things about the distribution of


00:16:50.959 --> 00:16:52.790
galaxies in the very local universe as


00:16:52.800 --> 00:16:55.189
well. So I would say hold tight and in


00:16:55.199 --> 00:16:56.870
sort of four or five years time when we


00:16:56.880 --> 00:16:58.230
have results from foremost we might be


00:16:58.240 --> 00:16:59.670
able to say something a bit more about


00:16:59.680 --> 00:17:00.389
this problem.


00:17:00.399 --> 00:17:02.389
>> The reason for this assumption that


00:17:02.399 --> 00:17:04.789
we're in a of the edge of a void is


00:17:04.799 --> 00:17:06.870
simply because of studies looking at


00:17:06.880 --> 00:17:08.470
expansion of the universe based on dark


00:17:08.480 --> 00:17:08.949
energy.


00:17:08.959 --> 00:17:11.029
>> Yeah. So that's one of the cosmological


00:17:11.039 --> 00:17:12.789
measurements that I mentioned. So there


00:17:12.799 --> 00:17:14.470
there's currently just this tension as


00:17:14.480 --> 00:17:17.029
to how dark energy is evolving and


00:17:17.039 --> 00:17:18.470
whether it's changing with time or


00:17:18.480 --> 00:17:19.990
whether it's a constant. And one of the


00:17:20.000 --> 00:17:21.829
potential solutions to all of this


00:17:21.839 --> 00:17:23.510
conflict is that we live within this


00:17:23.520 --> 00:17:25.590
void which actually allows you to match


00:17:25.600 --> 00:17:27.029
up some of the sort of slightly


00:17:27.039 --> 00:17:28.710
disperate observations that you get from


00:17:28.720 --> 00:17:29.750
doing different measurements.


00:17:29.760 --> 00:17:31.830
>> Yeah, it's a small void if it is a void.


00:17:31.840 --> 00:17:32.870
But uh


00:17:32.880 --> 00:17:34.470
>> the interesting thing is of course there


00:17:34.480 --> 00:17:35.830
have been some new results that have


00:17:35.840 --> 00:17:37.830
just come out showing that dark energy


00:17:37.840 --> 00:17:40.710
isn't constant but in fact we have not


00:17:40.720 --> 00:17:42.950
just reached the maximum extent of dark


00:17:42.960 --> 00:17:44.950
energy but it may be going in reverse


00:17:44.960 --> 00:17:45.510
now.


00:17:45.520 --> 00:17:47.669
>> Yes. So most of those results are coming


00:17:47.679 --> 00:17:49.830
out of a surveill called DESI which is


00:17:49.840 --> 00:17:52.630
done in the the northern hemisphere and


00:17:52.640 --> 00:17:54.230
not to bang on about foremost too much


00:17:54.240 --> 00:17:56.070
as a pretty amazing instrument when it


00:17:56.080 --> 00:17:57.190
starts going but there's also a


00:17:57.200 --> 00:17:58.549
different survey that's going to be done


00:17:58.559 --> 00:18:00.950
on foremost which is a survey which is


00:18:00.960 --> 00:18:02.549
similar to DESI but will be in the


00:18:02.559 --> 00:18:04.310
southern hemisphere. So when that's done


00:18:04.320 --> 00:18:06.710
combining the data from DESI and this


00:18:06.720 --> 00:18:07.990
foremost survey in the southern


00:18:08.000 --> 00:18:09.909
hemisphere will actually produce way


00:18:09.919 --> 00:18:11.590
better constraints on all of these


00:18:11.600 --> 00:18:12.950
measurements. So it's quite exciting


00:18:12.960 --> 00:18:15.110
that we might have sort of desi times


00:18:15.120 --> 00:18:16.950
two in about five years time where we


00:18:16.960 --> 00:18:18.390
get much better constraints on all of


00:18:18.400 --> 00:18:19.669
this and we'll probably then get a


00:18:19.679 --> 00:18:21.590
definitive answer on to whether dark


00:18:21.600 --> 00:18:23.350
energy is changing with time or is


00:18:23.360 --> 00:18:23.909
constant.


00:18:23.919 --> 00:18:26.070
>> That's associate professor Luke Davies


00:18:26.080 --> 00:18:28.150
from the University of Western Australia


00:18:28.160 --> 00:18:29.909
node of the international center for


00:18:29.919 --> 00:18:33.029
radioastronomy research and this is


00:18:33.039 --> 00:18:36.230
spacetime still to come. A new study


00:18:36.240 --> 00:18:38.710
suggests the solar systems two ice giant


00:18:38.720 --> 00:18:40.950
planets Uranus and Neptune may actually


00:18:40.960 --> 00:18:43.669
be more rocky than icy. And later in the


00:18:43.679 --> 00:18:46.070
science report, a new study warns


00:18:46.080 --> 00:18:48.230
insufficient sleep may shorten your


00:18:48.240 --> 00:18:50.470
lifespan. All that and more still to


00:18:50.480 --> 00:19:08.310
come on Spaceime.


00:19:08.320 --> 00:19:10.630
A new study suggests the solar systems


00:19:10.640 --> 00:19:12.789
two ice giant planets, Uranus and


00:19:12.799 --> 00:19:14.870
Neptune, might actually be more rocky


00:19:14.880 --> 00:19:17.270
than icy. The findings follow new


00:19:17.280 --> 00:19:19.270
computer simulations examining the


00:19:19.280 --> 00:19:21.510
likely internal structures of the two


00:19:21.520 --> 00:19:23.990
worlds. Now, this new study isn't


00:19:24.000 --> 00:19:26.070
claiming that these two blue planets are


00:19:26.080 --> 00:19:28.549
one type of the other, water or rock.


00:19:28.559 --> 00:19:30.870
Rather, it simply challenges the idea


00:19:30.880 --> 00:19:32.789
that ice rich isn't the only


00:19:32.799 --> 00:19:35.350
possibility. This new interpretation is


00:19:35.360 --> 00:19:37.029
also consistent with the discovery that


00:19:37.039 --> 00:19:39.909
the dwarf planet Pluto is rock dominated


00:19:39.919 --> 00:19:41.990
in its composition.


00:19:42.000 --> 00:19:44.150
The planets in our solar system are


00:19:44.160 --> 00:19:46.230
typically divided into three broad


00:19:46.240 --> 00:19:47.830
categories based on their general


00:19:47.840 --> 00:19:50.070
composition. There are the four


00:19:50.080 --> 00:19:52.390
terrestrial rocky planets, Mercury,


00:19:52.400 --> 00:19:55.510
Venus, Earth, and Mars. Then the two gas


00:19:55.520 --> 00:19:57.510
giants, Jupiter, and Saturn. And


00:19:57.520 --> 00:20:00.230
finally, the two ice giants, Uranus and


00:20:00.240 --> 00:20:02.789
Neptune. Now, according to the new work


00:20:02.799 --> 00:20:04.789
carried out by the University of Zurich


00:20:04.799 --> 00:20:06.789
scientific team, Uranus and Neptune


00:20:06.799 --> 00:20:09.270
might actually be more rocky than icy.


00:20:09.280 --> 00:20:11.430
The study's lead author, Luca Morph,


00:20:11.440 --> 00:20:13.669
says the ice giant classification might


00:20:13.679 --> 00:20:16.310
be an oversimplification, but he admits


00:20:16.320 --> 00:20:18.630
both worlds are still poorly understood


00:20:18.640 --> 00:20:20.710
and models on the two based on physics


00:20:20.720 --> 00:20:22.710
are too assumptionheavy, while imperial


00:20:22.720 --> 00:20:25.110
models are too simplistic. Morphin


00:20:25.120 --> 00:20:27.430
colleagues combined both approaches in


00:20:27.440 --> 00:20:29.430
order to get internal models of the two


00:20:29.440 --> 00:20:31.669
planets that are both agnostic and


00:20:31.679 --> 00:20:34.390
physically consistent. Now to do this


00:20:34.400 --> 00:20:36.549
they first started with random density


00:20:36.559 --> 00:20:38.630
profiles for each planet's interior


00:20:38.640 --> 00:20:41.110
based on a numerical framework. They


00:20:41.120 --> 00:20:43.029
then calculated planetary gravitational


00:20:43.039 --> 00:20:44.789
fields in a way that was consistent with


00:20:44.799 --> 00:20:47.029
the observed data available and that


00:20:47.039 --> 00:20:48.789
allowed them to infer a possible


00:20:48.799 --> 00:20:51.590
internal composition. Finally, the


00:20:51.600 --> 00:20:53.669
process is repeated to obtain the best


00:20:53.679 --> 00:20:55.590
possible match between models and


00:20:55.600 --> 00:20:58.230
observational data. And the authors


00:20:58.240 --> 00:20:59.909
found that the potential internal


00:20:59.919 --> 00:21:02.149
composition of the pair isn't limited to


00:21:02.159 --> 00:21:05.990
mostly ices. Instead, a new range of


00:21:06.000 --> 00:21:08.149
internal compositions show that both


00:21:08.159 --> 00:21:10.789
planets can either be water-rich ice or


00:21:10.799 --> 00:21:13.990
rockri material. The study has also


00:21:14.000 --> 00:21:16.149
brought a new perspective on both Uranus


00:21:16.159 --> 00:21:18.789
and Neptune's puzzling magnetic fields.


00:21:18.799 --> 00:21:20.470
While the Earth has clear north and


00:21:20.480 --> 00:21:22.149
south magnetic poles, the magnetic


00:21:22.159 --> 00:21:24.070
fields of Uranus and Neptune are far


00:21:24.080 --> 00:21:26.549
more complex and include more than just


00:21:26.559 --> 00:21:29.510
two poles. The new models show ionic


00:21:29.520 --> 00:21:31.510
water layers which generate magnetic


00:21:31.520 --> 00:21:34.070
dynamos at locations that help explain


00:21:34.080 --> 00:21:37.350
the observed nondipolar magnetic fields.


00:21:37.360 --> 00:21:39.430
They also found that Uranus's magnetic


00:21:39.440 --> 00:21:41.990
field originates far deeper inside the


00:21:42.000 --> 00:21:44.710
planet than that of Neptune. While these


00:21:44.720 --> 00:21:47.270
new results are promising, uncertainty


00:21:47.280 --> 00:21:50.230
still remains. One of the main issues is


00:21:50.240 --> 00:21:52.710
that physicists still barely understand


00:21:52.720 --> 00:21:54.870
how materials behave under the exotic


00:21:54.880 --> 00:21:56.710
conditions of pressure and temperature


00:21:56.720 --> 00:21:58.630
which are found at the heart of a planet


00:21:58.640 --> 00:22:01.510
and that will impact results. Still,


00:22:01.520 --> 00:22:03.430
despite the uncertainties, these new


00:22:03.440 --> 00:22:05.350
results are paving the way for new


00:22:05.360 --> 00:22:07.029
potential interior composition


00:22:07.039 --> 00:22:09.350
scenarios. scenarios which are


00:22:09.360 --> 00:22:11.909
challenging decades old assumptions and


00:22:11.919 --> 00:22:14.310
which could guide future research into


00:22:14.320 --> 00:22:16.470
planetary conditions.


00:22:16.480 --> 00:22:33.750
This is spacetime.


00:22:33.760 --> 00:22:35.270
And time now to take a brief look at


00:22:35.280 --> 00:22:37.029
some of the other stories making news in


00:22:37.039 --> 00:22:39.909
science this week with a science report.


00:22:39.919 --> 00:22:42.870
A new study warns insufficient sleep may


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shorten your life. The findings reported


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in the journal Sleep Advances compared


00:22:47.919 --> 00:22:50.470
sleep patterns with life expectancy. And


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the authors found that as a behavioral


00:22:52.720 --> 00:22:55.510
driver for life expectancy, sleep stood


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out far more than diet, exercise,


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loneliness, and indeed more than any


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other factor except smoking. For the


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study, the CDC, the Centers for Disease


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Control and Prevention, defined


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sufficient sleep as at least 7 hours per


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night, which is recommended by the


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American Academy of Sleep Medicine and


00:23:13.120 --> 00:23:15.669
by the Sleep Research Society. Although


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previous research has shown broadly that


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a lack of adequate sleep does lead to


00:23:19.679 --> 00:23:22.230
high mortality risk, the new research is


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the first to reveal year-to-year


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correlations between sleep and life


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expectancy.


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The World Meteorological Organization


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says there's now a 55% chance of a weak


00:23:33.679 --> 00:23:35.750
leninia weather pattern developing over


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the next 3 months. Leninia conditions


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typically bring higher rainfall and


00:23:40.799 --> 00:23:42.710
cooler temperatures across Australia.


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And the study's authors say climate has


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been at borderline leninia conditions


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since mid- November. The agency says


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Leninia is just one of the climatic


00:23:51.679 --> 00:23:53.590
patterns influencing our weather with


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climate change also having a major


00:23:55.679 --> 00:23:57.750
impact on temperatures and extreme


00:23:57.760 --> 00:24:00.230
weather events.


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One of the longest and most intact


00:24:02.159 --> 00:24:04.310
segments of Jerusalem's city wall has


00:24:04.320 --> 00:24:06.310
been uncovered by archaeologists with


00:24:06.320 --> 00:24:09.110
the Israeli Antiquities Authority. The


00:24:09.120 --> 00:24:11.350
remarkably well preserved segment dates


00:24:11.360 --> 00:24:13.830
back to the Hassamean Makabe period of


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the late 2nd century B.C.E. Some 200


00:24:17.360 --> 00:24:20.230
years before Christ and 800 years before


00:24:20.240 --> 00:24:22.870
the birth of Islam, the ancient Jewish


00:24:22.880 --> 00:24:24.870
fortification was unearthed within the


00:24:24.880 --> 00:24:27.190
Kishel complex at the Tower of David


00:24:27.200 --> 00:24:29.669
adjacent to the historic citadel. The


00:24:29.679 --> 00:24:32.310
newly uncovered segment is over 40 m


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long and some 5 m wide. It was built


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from massive stone blocks that were


00:24:37.039 --> 00:24:38.549
finally dressed with a distinctive


00:24:38.559 --> 00:24:40.950
chiseled boss typical of the Himmonian


00:24:40.960 --> 00:24:43.350
period. The authors believe the wall


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originally stood over 10 m high. Similar


00:24:47.039 --> 00:24:48.870
sections of the defensive system have


00:24:48.880 --> 00:24:50.870
been uncovered around Mount Zion, the


00:24:50.880 --> 00:24:52.710
city of David, the courtyard of the


00:24:52.720 --> 00:24:54.950
citadel, and along parts of the western


00:24:54.960 --> 00:24:57.510
boundary of Jerusalem, but none are as


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extensive or as well preserved.


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A new study by Noah, the National


00:25:03.360 --> 00:25:05.590
Oceanic and Atmospheric Administration,


00:25:05.600 --> 00:25:07.830
has debunked the idea that increases in


00:25:07.840 --> 00:25:10.070
atmospheric carbon dioxide levels will


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provide long-term improvements in plant


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growth. Skeptics Tim Mendum says while


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some increases in CO2 levels are


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beneficial for plants, too much does end


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up killing them.


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>> There's a lot of people saying that


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because we're putting out carbon dioxide


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as part of our sort of energy activities


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and that plants take in carbon dioxide


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to help them grow. If it's a good thing


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we're putting out the food that plants


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use. That's actually to a certain


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extent, a little extent, that's correct.


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Plants do take on carbon dioxide. And


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there can be times when they flourish in


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certain environments, but the trouble is


00:25:39.919 --> 00:25:41.830
you can have too much and plants can


00:25:41.840 --> 00:25:43.750
only absorb so much in the same way as


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the sea can only absorb so much. In


00:25:45.760 --> 00:25:47.590
fact, it's the sea which is absorbing


00:25:47.600 --> 00:25:49.110
most of the carbon dioxide that is


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absorbed. So the trees can only take so


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much they can bloom and blossom and then


00:25:52.559 --> 00:25:53.830
after a while it'll start to kill them.


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And then when it kills them, you get


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drought. So you get less trees and that


00:25:56.480 --> 00:25:57.909
sort of stuff. Also, of course, when a


00:25:57.919 --> 00:25:59.350
plant dies, it gives up the carbon


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dioxide it's taking in and storing,


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especially for trees and things like


00:26:02.559 --> 00:26:04.710
that. So, the argument that's being put


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forward by a lot of people saying that


00:26:06.320 --> 00:26:08.230
carbon dioxide is good for plants and


00:26:08.240 --> 00:26:09.990
things and therefore we'll reforest


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everything is wrong. And this has been


00:26:11.520 --> 00:26:14.149
shown both in laboratory work and in


00:26:14.159 --> 00:26:15.830
atmospheric work and satellite


00:26:15.840 --> 00:26:17.510
photography. So, what will happen is


00:26:17.520 --> 00:26:19.430
that plants will flourish and then die.


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And when they die, you get drought, you


00:26:20.880 --> 00:26:22.070
get low crop yield.


00:26:22.080 --> 00:26:24.230
>> That's Tim Mendum from Australian


00:26:24.240 --> 00:26:40.230
Skeptics.


00:26:40.240 --> 00:26:43.110
and that's the show for now. Spacetime


00:26:43.120 --> 00:26:44.950
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>> You've been listening to Spacetime with


00:27:28.640 --> 00:27:30.950
Stuart Garry. This has been another


00:27:30.960 --> 00:27:32.789
quality podcast production from


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