Transcript
[0:01] This is Space Time, Series 26, Episode 10, for broadcast on the 23rd of January, 2023. Coming up on Space Time… What brought the dwarf planet Ceres to life?
Lons de Light in the sky with diamonds?
And failure for Britain's first orbital rocket launch from home soil?
All that and more coming up on Space Time. Welcome to Space Time with Stuart Gary.
[0:29] Music.
[0:46] A new study suggests that the radioactive decay of some elements could account for all the heat needed to drive active geology early in the history of the dwarf planet Ceres.
At 945 km, Ceres is the largest spot in the main asteroid belt between Mars and Jupiter. But even though it contains a full third of the mass of the entire main asteroid belt,
it's still so small it was always assumed to be inactive.
The belt includes hundreds of thousands of asteroids spanning the snow line. The distance from the Sun where it's cold enough for volatile compounds such as water, ammonia, methane, carbon dioxide and carbon monoxide,
to condense into solid ice grains.
And Ceres appeared indistinguishable from any other mainboard asteroid in early telescopic observations from Earth.
[1:40] But all that changed in 2015, when this hazy orb suddenly came into sharp focus, thanks to the spectacular observations undertaken by NASA's Dawn spacecraft.
All of a sudden, Ceres became a real world, and one quite unique.
[1:58] We now know the dwarf planet appears to be differentiated to a rocky core in an icy mantle, and it may even have a remnant internal ocean of liquid water hiding under its icy crust.
Ceres' surface is a mixture of water ice and various hydrated minerals, such as carbonates and clays.
The data and images collected by Dorn have given a clearer picture of the dwarf planet's surface, including its composition and structure, and it's also revealed unexpected geological activity.
See, Dorns discovered a large continental-sized plateau on one side of Ceres, which actually covers a significant fraction of this frozen world.
Surrounding it were fractures in rocks, all clustered in one location. And there were visible traces of an ocean world, thanks to deposits all over the surface, where minerals had condensed as water evaporated, evidence of a freezing ocean.
And all this raises the question, where did Ceres get the energy to allow for the kind of geological activity that could account for the surface features seen by Dawn?
A possible answer is in a report in the journal AGU Advances.
It concludes that the heat needed to keep a small ward like Ceres active could be found in the decay of radioactive elements within Ceres' interior.
[3:19] The authors of the study reached their conclusions following detailed computer modelling. The study's lead author, Scott King from Virginia Tech, says studies of big planets such as Earth, Venus and Mars have shown that planets all start out hot.
Collisions between objects that form planets creates this internal heat.
But in contrast, Ceres simply never got big enough to become a planet and generate the to hate in that way.
To learn how Ceres could still generate enough heat to power geological activity, King and colleagues used theories and computational tools previously applied to bigger planets,
in order to study the dwarf world's interior. They then looked for evidence that could support,
their models in the data returned by the Dawn mission. The team's model of dwarf planet interiors showed a unique sequence. It seems Ceres started out cold, but then heated up because of the decay of radioactive elements such as thorium and uranium.
[4:19] And this alone would have been enough to power geological activity until the interior became unstable.
King says he then noticed that all of a sudden one part of Ceres' interior would start heating up and moving upwards while another part would be moving downwards.
And it's that instability which could explain at least some of the surface features that have been formed on Ceres as revealed by the Dawn mission.
The large plateau that formed an only one side of Ceres with nothing on the other side and the big fractures that all clustered at just one location around it.
The concentration of features in just one hemisphere signalled to King that instability had occurred and had left a visible effect.
[5:01] King says it turns out that he could show through the modelling that where one hemisphere had an instability that was rising up that would cause an extension at the surface and And that was consistent with the patterns of fractures seen on Ceres.
So based on this model, Ceres didn't follow a typical planetary pattern, hot first, then cold later.
But instead it had its own pattern of cold first, then hot, and then cool again. King says it shows that radiogenic heating on its own is enough to create interesting geology.
He sees similarities to Ceres in the moons of Uranus, which is study commissioned by NASA and the National Science Foundation recently deemed a high priority for a major robotic mission.
[5:45] NASA's Dawn spacecraft was launched back in September 2007 on a mission to explore the two worlds of Vesta and Ceres, the two largest bodies in the main asteroid belt between Mars and Jupiter.
The 1,218 kilogram spacecraft achieved orbit insertion around Vesta in July 2011. Vesta is by far the brightest asteroid visible from Earth,
and it contains some 9% of the total mass of the main asteroid belt.
The 525 kilogram wide world has a differentiated internal structure, typical of terrestrial planets, with a metallic iron-nickel core surrounded by a rocky mantle.
Then after 14 months of surveys, Dawn left Vesta and travelled to its second target, the dwarf planet Ceres, arriving there in March 2015.
Dawn studied Ceres until October 2018 when it ran out of fuel, and it remains in orbit around the frozen dwarf world.
This is space time. Still to come.
[6:49] Lons of the light in the sky with diamonds. And failure for Britain's first orbital rocket launch from home soil.
All that and more still to come on Space Time. Scientists searching for meteorites in outback South Australia are finding diamonds embedded.
[7:00] Music.
[7:22] In the space rocks.
[7:24] These are microscopic grains. They're known as Lonsdalites and they reside deep inside Uralite meteorites. Lonsdalites are a rare hexagonal form of diamond crystal.
And these are now thought to have originated in the mantle of an ancient dwarf planet which was hit by an asteroid around four and a half billion years ago.
Lonsdalite is named after the famous British pioneering female crystallographer Dame Kathleen Lonsdale. the first woman elected as a fellow to the Royal Society.
[7:55] A team of scientists carried out a series of tests trying to determine how lonsdolites formed.
The authors used advanced electron microscopy techniques in order to capture solid and intact slices of meteorites to create what are really snapshots of how lonsdolite and regular diamonds are formed.
Their findings, reported in the Journal of Proceedings of the National Academy of Sciences, PNAS, suggest that Lons Delites are formed in very different ways to other diamonds.
And during their analysis, they also discovered what are now considered to be the largest Lons Delite crystals known to date.
These are up to a micron in size, still much thinner than a human hair.
The authors say they think there's strong evidence that there's a newly discovered formation process for Lonsdaleite crystals as well as regular diamonds.
[8:49] This would be like a supercritical chemical vapour deposition process that has taken place in these space rocks, probably in the dwarf planet, shortly after a catastrophic collision.
And that's interesting because chemical vapour deposition is one of the ways humans make artificial diamonds in the laboratory, essentially by growing them atom by atom in a specialised chamber.
The study's lead author, Professor Andy Tompkins from Monash University, says the hexagonal structure of Lonsdaleite atoms makes it potentially much harder than regular diamonds, which have a cubic structure.
The unusual structure could help inform new manufacturing techniques for ultra-hard materials, especially in things like mining applications.
Tompkins says Lonsdaleite in meteorites form from a supercritical fluid at a high temperature but at moderate pressures, almost perfectly preserving the shape and textures of the pre-existing,
graphite. He says that later it was partially replaced by a diamond as the environment cooled and the pressure decreased.
Tompkins thinks Lonsdaleit could be used to make tiny ultra-hard machine parts. That's if they can develop an industrial process that promotes replacement of pre-shaped graphite pads with Launch Delight.
[10:04] But he says the important thing is that the study helps address the long-term standing mystery regarding the formation of different carbon phases in urolight meteorites.
These are the diamonds we found in urolight meteorites, one of the largest group of achondrite meteorites that we have in the global collection.
Scientists have known about the diamonds in urolights for quite a long time. But there's been a long debate about how the diamonds might have formed. So the long thought idea is they formed at high pressure when there was a big impact that disrupted the ureolite parent body, parent asteroid.
And we're suggesting a new way that they formed by a sort of a mechanism that's similar to the way that they made today in the lab. How are they made in the lab these days? OK, so a lot of the time in the lab, they're made by a process called chemical mapadeposition.
And the way that works is they use a little seed diamond, like a tiny little diamond particle, and then they grow more diamond on top of that.
And they do that in a low pressure atmosphere that's hydrogen and methane and carbon monoxide.
[11:01] And the methane has carbon in it so the diamond literally goes from the carbon gas onto that sea diamond. So that happens at very high temperatures, 1000 degrees plus and lower pressure, so less than one atmospheric pressure.
And we're suggesting a similar sort of thing happened inside Demetra as the asteroid was disrupted by a large impact. Now that's very different to the way diamonds are normally formed on Earth usually in giant vents.
Yeah, so on Earth they normally form in the mantle, they're around about 150 feet down, and they're brought to the surface by volcanoes in their mind in Africa and Australia and Canada as those vent deposits of diamonds are brought up in the lava.
You stated the unusual structure of the diamond. Yeah, so I was actually looking down the microscope at these diamonds just to try and understand it a little bit better and we found these unusual fold shapes looking like,
bent crystals of diamond. The diamond is really really hard so if the immediate,
what comes to mind how and if you possibly hold diamonds.
The hardest thing you know. And so we did a little bit more work sort of delving into what could be going on here with Electron, lots of smooch.
[12:04] CSIRO and the transmission electron microscope at MIT and found out that the diamond was actually a hexagonal diamond called Lonsdaleite. So it's a little bit different to normal cubic diamond that
we're used to thinking about diamond rings and that sort of thing. This one's hexagonal and maybe even a little bit harder than regular diamond. So we were able to map the distribution of Lonsdaleite and normal regular diamond in the meteorites using some of the electron microscope techniques.
And that was, we were able to make some pretty cool maps out of that process. Are all Lonsdalite diamonds from extraterrestrial sources?
[12:36] I think they've been able to make some in the lab as well by chemical localization. Right. But they haven't been out.
So yeah, the ones in Nausia that have been overflown in the future, it's a kind of a future as well.
And the other exciting thing is their extraterrestrial origins. This is where dwarf planets in our area of the universe comes in. Yes, the other area is, I think that the Eurylochian body was quite large.
And if it was larger than about 500 kilometers, it would have been probably just getting into a better size range where it could start forming a spheroidal shape, something like this, or.
[13:07] Sort of bordering on being a dwarf planet and a serous dwarf planet, sort of thing. So they're the biggest asteroids in the solar system. Yeah, and so the urolights are thought to be from the
mantle of a dwarf planet, or a very large asteroid. We're not quite sure how big it is. So they come from very, very deep down beneath the surface. And they were sort of liberated by a gigantic,
impact that happened about five million years after the asteroid first formed.
Our listeners may have noticed that you're fading in and out and that's because you're at a really interesting place right now. You're basically on the very edge of the Nullarbor Plain in outback South Australia near Old Deer. Tell me about it. What are you doing there?
Yeah, so we're out on the Nullarbor Plain and trying to find more meteorites. Nullarbor is probably the best place in Australia to try and find meteorites because it's this large limestone covered plain in a sort of a desert sort of environment. So limestone's good because it's a white rock and meteorites tend to be dark so it can walk around across the desert for many,
kilometers and pick out all the dark rocks amongst the light colored rocks and the dark one.
[14:08] Has a good chance of being meteorite. And then the desert is lonely because the low rainfall.
[14:13] Meteorites don't weather away and rust away and be destroyed over time. And they don't get buried by sediment either. So basically what we do is turn out here and try and find some more meteorites.
We have quite a large collection of meteorites from the motherboard now. That's where most of Australia's meteorites come from. We even have found urulite meteorites in the motherboard as well. They were included in that study we've just published. So you get some pretty cool science results on the meteorites we find here. That's Professor Andy Tompkins from Monash University.
And this is space time. Still to come. Failure for Britain's first orbit rocket launch off home soil and later in the science report. New data shows COVID-19 is now the third highest cause of death in Australia. All that and more still to on space time.
[15:01] Music.
[15:16] Britain's Air Accidents Investigation Board will work together with Washington's FAA to determine the exact cause of Virgin Orbit's failed rocket launch from the UK spaceport Cornwall earlier this month.
[15:30] The mission saw Virgin Orbit's modified Boeing 747-400 airliner Cosmic Girl drop-launch the company's two-stage rocket launcher-1 from a pylon under the jet's port wing in the,
skies 35,000 feet above the North Atlantic Ocean off the coast of southwestern England.
Following its launch, the first stage of the Launcher One rocket performed nominally. We have, it looks to be a successful ignition of the Stage One engine as we make our way to space.
We're actually getting towards the end of our Stage One burn. Everything is nominal so far. We've had our pitch up on the bottom on the burn time.
We have made it through Max-Q alpha, which is one of the most stressful physical moments for the rocket. Very comfortably through Max-Q and then also through our aerodynamic heat heating.
We have made it through MECO, our main engine cutoff. That is our Newton 3 engine shutdown is reported as nominal. Bearing, brake wire is broken.
Once that was exhausted and jettisoned, the second stage lit up. The trajectory is now tracking Launcher 1 as she makes her way down the Atlantic Ocean,
towards the Canary Islands.
Stage 2 trajectory nominal.
That means our flight path is as expected being picked up by those ground stations.
[16:54] We're probably almost coming up on halfway through our stage 2 burn number 1. Altitude now is looking at around about 600,000 feet.
Approximately three miles per second. Bus voltages for the batteries are nominal. We had a lower voltage while we were in captive air and that's because the power was being provided by Cosmic Girl at that point before we switched over to the rocket's internal batteries.
Stage two burn is a little longer than the stage one burn so this might take a little while for us to get to second engine cutoff one.
There are points of the flight where we don't have the telemetry coming from the rocket because we are out of view of the ground stations.
Flight software folks have implemented a store and forward on our rocket which means that when we are out of view of the ground stations we are storing that data so that the next time we do come in view of ground station we can download,
it and from target back from Madrid data source switch to Madrid Madrid ground station has locked on to our rocket and is streaming the data now confirmed signal from mass below miss switching telemetry source to mass below miss.
[17:59] Newton 4 shutdown initiated.
You just heard the call for a Newton 4 shutdown. Newton 4 is our stage 2 engine. engine. So that is the completion of the first burn.
Of our second stage. But then failed to deploy its nine satellite payload, apparently due to a technical issue somewhere in the second stage rocket engine. It appears that Launcher One has suffered an anomaly which will prevent us from making orbit for this mission. We are looking at,
the information and data that we have gotten. The failed launch was also the first rocket launch attempt by Virgin Orbit outside its home base at the Mojave Air and Space Port in California.
And it comes in the lead up to plans for a demonstration launch at Queensland's Toowoomba Airport in 2024.
Britain has previously successfully launched orbital rockets. They were in association with Australia from the Woomera rocket range in outback South Australia.
But the Virgin Orbit launch failure was the first launch attempt from British soil.
Is space-time. And time now to take a brief look at some of the other stories making news in science.
[19:00] Music.
[19:20] This week with the Science Report.
[19:23] A new study shows that COVID-19 is now the third highest cause of death in Australia. The figures were reported by AusAGE, a broad group of medical experts looking at the well-being of Australians before, during and after the COVID-19 pandemic.
The organisation provided a comparison of causes of deaths in recent years and says it's clear more needs to be done to reduce the excess deaths coming from COVID.
This would include higher levels of booster vaccinations, delivery of safe indoor air in public settings, the use of masks in poorly ventilated indoor areas, the return to free wildly accessible testing and a review of the mitigations being used in high-risk settings,
such as aged care facilities.
The group warns that there's every indication that unless Australia changes its stance on managing COVID-19, this trend will continue well into 2023.
So far over 6.8 million people have been killed by the COVID-19 coronavirus since it was first detected near the Wuhan Institute of Virology around September 2019.
The World Health Organization now estimates the true death toll from COVID-19 is likely to be around 16 million, with some 672 million confirmed cases globally.
[20:48] It's often been claimed that working from home can boost productivity, but new research shows that this was actually less likely to have been the case during the COVID-19 pandemic.
[21:00] The findings reported in the journal PLOS One are based on 37 studies, two-thirds of which were conducted before the COVID-19 pandemic took hold. Pre-pandemic, the researchers say the majority of
studies showed working from home actually boosted productivity and performance, and mostly positive impacts on work-life overall were noted.
However, follow-up mid-pandemic studies say 27% showed positive impacts, 38% showed negative impacts and another 38% reported mixed results.
Researchers say that while more studies are now needed, especially around productivity and performance, their research indicates that non-mandatory working-from-home arrangements may be more successful.
[21:47] A new Australian study suggests that boiling peanuts may reduce most of what triggers allergies from the legumes, meaning that ultimately peanuts could potentially be reintroduced to people to eliminate their peanut allergies.
The findings, reported in the journal Clinical and Experimental Allergy, are based on tests conducted on 70 children aged between 6 and 18, all of whom had peanut allergies.
They were each given 12-hour boiled peanuts for 12 weeks, 2-hour boiled peanuts for 20 weeks, and finished with roasted peanuts for 20 weeks.
Researchers found that 56 kids, that's 80% of the 70 participants, became desensitised to peanuts.
But the authors say treatment-related adverse effects were still reported in 43 participants at 61%, three of whom had to withdraw from the trials.
[22:42] Paranormal enthusiasts around the world have been hotly debating the scenes shown in a disturbing video of a flock of sheep in Inner Mongolia in China that have been apparently walking around in a circle for at least 12 days straight.
The farm owner claims what makes the entire ordeal mysterious is that although there are 34 sheep enclosures on the farm, these sheep were all from the same enclosure.
Number 13. And as you'd expect, that sent the supernatural snoops into a feeding frenzy, looking for any signs that this is the number of the beast, which I actually thought was 666.
Tim Mendham from Australian Skeptics says, despite a multitude of supernatural explanations being offered by paranormal investigators, the real answer is a bacterial disease called Listeriosis, which does affect sheep in this way.
[23:34] Caused by sheep eating contaminated food and it can be treated with an early aggressive course of antibiotics. There's a video which has just appeared recently which has been described as eerie and bizarre which shows a flock of Mongolian sheep walking in circles which they did for about 12 days.
They thought it's really weird, is this paranormal, is this sort of strange behavior that's been coming from outer space or aliens or whatever. The interesting thing is There is actually a disease called Listeriosis.
It causes exactly the same circumstance.
It actually makes things walk in circles and often actually favor one side more than the other.
So when you get a flock of sheep that are going around in circles for this, it's normally – it's probably only this disease, this Listeriosis, which does exactly what they was talking about.
So the article I saw about this thing, about this sheep, ran through all the paranormal explanations and said, oh, by the way, this is the reason why it's happening.
It's rather sad that people make all this effort to promote a occurrence whether it's eerie or not with the most simple rational and exact accurate assessment of it that finds out the real cause. Sheep walking in circles is probably due to Listeriosis, end of story. Occam's razor, the simplest explanation is usually the best. That's right Occam's razor says you don't have to go to all this extent of finding paranormal explanations and things for something which is readily explained very,
That's Tim Mendam from Australian Skeptics.
[25:03] Music.
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[26:45] And space time is brought to you in collaboration with Australian Sky and Telescope magazine, your window on the universe. You've been listening to space time with Stuart Gary. This has been another quality podcast production from Bytes.com.