Earth's Water Origins Rewritten, Mars' Magnetic Mystery Unveiled

[00:00:00] This is Space Time Series 28 Episode 50, for broadcast on the 25th of April 2025. Coming up on Space Time, new evidence overturning theories on the origins of Earth's water, the strange mystery of the Red Planet's magnetic field, and what are humanity's oldest known meteor showers, now on full display. All that and more coming up on Space Time. Welcome to Space Time with Stuart Gary.

[00:00:44] Scientists have uncovered crucial new evidence overturning earlier hypotheses on the origins of Earth's water. The findings, reported in the journal Icarus, show that instead of coming from asteroid and comet impacts, the new data shows that Earth's water formed together with the early proto-Earth itself. Using a rare type of meteorite known as a statite chondrite, which has a composition analogous to that of the early Earth 4.55 billion years ago, the authors have found a source of hydrogen which would have been critical for the formation of water molecules.

[00:01:14] Now, crucially, the authors have demonstrated that the hydrogen present in this material was intrinsic, and not from contamination. And this suggests that the material from which our planet was built was far richer in hydrogen than previously thought. Without hydrogen, a fundamental elemental building block of water, it would have been impossible for planet Earth to develop the conditions needed to support life as we know it. So, the origins of hydrogen and by extension water on Earth has been a key issue of debate.

[00:01:42] The authors analyzed the elemental composition of a meteorite known as LAR 1225-2, originally collected from Antarctica. They used an elemental analysis technique called X-ray absorption near-edge structure spectroscopy at the Diamond Light Source Synchrotron in Oxfordshire. X-ray absorption near-edge structure spectroscopy is used to identify what elements are in the material by shining X-rays onto a sample, causing the atoms to absorb energy in a way that depends on what the element is,

[00:02:10] the chemical form it's in, and how the atoms are all bonded to one another. A previous study led by a French team had originally identified traces of hydrogen within the meteorite inside organic materials and non-crystalline parts of the chondral's millimeter-sized spherical objects within the meteorite. However, the remainder was unaccounted for, meaning it was unclear whether this hydrogen was native to the meteorite or due to contamination once it arrived on Earth.

[00:02:36] The authors of the new study suspected that a significant amount of hydrogen may have been attached to the meteorite's abundant sulfur content. Using the synchrotron, they shone powerful X-rays onto the meteorite structure in order to search for sulfur-bearing components. When initially scanning the sample, the authors focused their efforts on the non-crystalline parts of the chondral's, where the hydrogen had been found before. But when serendipitously analyzing the material just outside one of these chondral's,

[00:03:03] composed of a matrix of extremely fine sub-micrometer material, they discovered that the matrix itself was incredibly rich in hydrogen sulfide. In fact, their analysis showed that the amount of hydrogen in the matrix was five times higher than that in the non-crystalline sections. In other parts of the meteorite that had cracks and signs of obvious contamination such as rust, very little or no hydrogen was present. And all this makes it highly unlikely that the hydrogen sulfide compounds detected by the authors

[00:03:32] originated from an Earth source. Now, since the early proto-Earth was made from materials similar to N-stattite chondrites, it suggests that by the time the forming planet had become large enough to be struck by asteroids, it would have already amassed enough reserves of hydrogen to explain Earth's present-day water abundance. The study's lead author, Tom Barrett from the University of Oxford, says analysis shows that the samples contain hydrogen sulfide, but just not where it was expected.

[00:03:58] And because the likelihood of this hydrogen sulfide originating from terrestrial contamination was very low, the research provides key evidence to support the theory that water on Earth is native, that it was a natural outcome of what our planet was made of. See, a fundamental question for planetary scientists is how the Earth came to look the way it does today. This finding supports the idea that the formation of water on Earth was a natural process,

[00:04:23] rather than simply a fluke of hydrated asteroids and comets bombarding the planet after it had already formed. This is space-time. Still to come, the strange mystery of the red planet's magnetic field and one of humanity's oldest known meteor showers, now putting on a full display in the night skies. All that and more still to come, on Space-time.

[00:05:00] A new study suggests strange magnetic signatures detected on the red planet Mars could be due to a partially molten core only covering the Martian southern hemisphere. Like Earth, Mars once had a strong magnetic field that shielded its once thick atmosphere from the solar wind. But Mars is a lot smaller than the Earth, just a third its size, and so it's cooled a lot more quickly.

[00:05:24] As the planet cooled and solidified, its molten liquid-iron core, the geodynamo needed to generate its planetary magnetic field, also solidified and ceased working. Now, without a protective magnetic shield, the solar wind and cosmic rays gradually eroded away the Martian atmosphere, allowing the planet's water to degas into space, and turning the red planet from a warm, wet world capable of supporting life, had it ever existed there, into the freeze-dried, irradiated desert it is today.

[00:05:53] Now, only a magnetic imprint of that ancient shield remains. But what's long baffled scientists is why the imprint appears most strongly in only its southern half. See, Mars has a dramatic hemispheric dichotomy where the topography, terrain and the magnetic field of the northern hemisphere's lowlands and southern hemisphere's highlands are dramatically different. Now, a new study, reported in the journal Geophysical Research Letters, could help explain this one-sided imprint.

[00:06:21] It presents evidence that the planet's magnetic field covered only its southern half. The study's lead author, Chai Yan from the University of Texas, says the resulting lopsided magnetic field would have matched the imprint we see today. Of course, it would also make the Martian magnetic field very different from Earth's, which covers the entire globe. Yan says that the one-sided magnetic field could arise if Mars' inner core was liquid.

[00:06:47] He says that with no solid inner core, it's much easier to produce a one-sided hemispheric magnetic field. And that would have implications for Mars' ancient geodynamo, and possibly how long it was able to sustain an atmosphere. Yan and colleagues reached their conclusions using supercomputer simulations to model their scenario. Until now, most studies of early Mars had relied on magnetic models that gave the red planet an Earth-like inner-solid core, surrounded by a molten outer core.

[00:07:16] But the authors were inspired to try simulating a fully liquid core after NASA's Mars InSight lander found the red planet's core was made of much lighter elements than expected. That means the core's melting temperature is different from that of the Earth, and therefore quite possibly fully molten. If the red planet's core is still molten now, it almost certainly would have been fully molten 4 billion years ago when the Martian magnetic field is known to have been active.

[00:07:41] To test the idea, the authors prepared simulations of early Mars with a liquid core, and then ran them a dozen times on supercomputers. With each run, the authors made the planet's northern half of the mantle a little hotter than the southern half. Eventually, the temperature difference between the hotter mantle in the north and the cooler mantle in the south led to the heat escaping from the core to be released only at the southern end of the planet. Now, channeled this way, the escaping heat was sufficiently vigorous to drive a geodynamo

[00:08:10] and generate a strong magnetic field focused on the southern hemisphere. A planetary geodynamo is a self-sustaining mechanism that generates a magnetic field, typically through movement in a molten metallic core. These new findings offer a compelling alternative theory to a common assumption that involves asteroid impacts obliterating evidence of a planetary-wide magnetic field in the northern hemisphere's rocks. This is Space Time. Still to come, the Lyrids meteor shower now on full display,

[00:08:40] and later in the Science Report, the world's first full combination eye and face transplant. All that and more still to come on Space Time. One of humanity's oldest known meteor showers, the Lyrids, are now on full display in the night sky.

[00:09:10] They were first recorded some 2,700 years ago by Chinese scientists in the 7th century BCE. The Lyrids come from the tale of the comet Thatcher, which last came close to the Sun back in 1861. This comet takes more than 400 years to complete its orbit around the Sun, so it won't be close to Earth again until the 23rd century. Although not as plentiful as the Perseids meteor showers in August or the Geminids in December, the Lyrids will still make an entertaining celestial show over the next week.

[00:09:40] Dr Robert Massey, deputy executive of the Royal Astronomical Society, says the Lyrids can be spotted because they look like short, fuzzy streaks of light across the night sky. With the Lyrids, you'll be looking really for a little flurry of short-lived streaks of light, what you might popularly call shooting stars. Now, with this particular shower, you could expect to see maybe 10 to 15 an hour at the peak, so it's not massively prolific because, you know, you can look in the wrong part of the sky when one happens.

[00:10:09] But if you've got a clear sky, it's still very much worth a look. A meteor shower originates essentially from bits of comets, bits in cometary tails entering the Earth's atmosphere. What you have to imagine is that you've got these small particles running into the atmosphere at high speed. There's a lot of friction as they come into the upper atmosphere of the Earth. They heat up, the air around them is superheated, and you see this streak of light as a result. The Lyrids are like many meteor showers, they've been observed for a long time,

[00:10:37] but these are particularly special because in this case, we think they're the earliest meteor shower ever seen. More than 2,700 years ago, right back in the 7th century BC. The good thing about a meteor shower, and the Lyrids are no exception, is that you don't need any special equipment. The best equipment is just your eyes, you're looking up at the sky. Now in this particular case, the radium, the point of the sky they appear to come from, is in the constellation of Lyra, in bright star Vega, perhaps the Sun and Triangle.

[00:11:05] And so if you're looking in the small hours of the morning, which is essentially the best time to be watching, if you've got a clear sky, really just look up. The radium will be slightly over towards the east, but it's not absolutely critical which direction you look. That's Robert Massey, the Deputy Executive Director of the Royal Astronomical Society. And this is Space Time.

[00:11:39] And time out to take another brief look at some of the other stories making news in science this week, with a science report. A new study has shown that two mixtures of common food additives could be linked to an increase in the risk of type 2 diabetes. A report in the journal PLOS Medicine looked at a French cohort of 108,643 people and found two of five frequently consumed food additive mixtures were linked with type 2 diabetes.

[00:12:05] The first mixture is mostly found in a variety of industrially processed foods, such as broth, dairy desserts, fats and sauces. While the second mixture is often found in artificially sweetened beverages and sugary drinks. Paleontologists have for the first time identified the footprints of an armoured Ankylosaur dinosaur. Ankylosaur is a stubby, spiky, scaly, tank-like herbivores with tail clubs that roamed what are now the Canadian Rockies during the middle of the Cretaceous period

[00:12:34] between 100 million and 94 million years ago. A report in the journal Vertebrate Paleontology claims the 100 million year old fossilised footprints belonged to Ankylosaurid Ankylosaurus, which would have been about 5 to 6 metres long, with a sledgehammer-like tail club and only three toes on each foot, unlike the better known four-toed Notosaurid Ankylosaurus which had flexible tails. The tracks were uncovered at sites at both Tumbler Ridge in British Columbia and in north-western Alberta.

[00:13:03] Scientists say the transplanted eye of the ward's first whole eye and face transplant recipient is responding to light, although the recipient himself can't see it. The team tested the response of his retina, the light-sensitive screen at the back of the eye, to light, finding there was some retinal function. A report in the Journal of the American Medical Association claims that although the patient can't see through his new eye, the experts say its pressure is normal and blood flow is good.

[00:13:29] They say this is the first successful whole eye transplant without rejection by the body and a promising step towards being able to restore sight. The 46-year-old transplant recipient suffered a high-voltage electrical injury in 2021, resulting in the loss of his left eye, eyelid, nose, lips and facial tissue. Initial surgical reconstruction left him struggling to eat and breathe comfortably, issues the full face transplant, which was also not rejected by his body, as help to address.

[00:13:58] A survey of Australian, Canadian and American TikTok users has found that 87% of millennials and Generation Z's got at least some of their health advice from social media. The findings come hot on the heels of the Netflix drama series based on the actions of convicted con artist, Bill Gibson. Tim Mendham from Australian Skeptic says the findings show that people are ripe for the picking and the pickers are out there in large numbers. Bill Gibson was a young woman, quite attractive, so that helped in promoting her cause,

[00:14:28] who claimed she had brain cancer and that it had been cured or was being cured with certain diets and exercise and lifestyle issues and things like that. She put on an influencer sort of website that she had, pronouncing all this, stalling the virtues to this, and people thought, oh, wonderful, because she's actually pretty as well and helps her sell her story. People saying, oh, great, we're so happy for you. I've got brain cancer, what do I do? And then she'd start selling things. Or she'd take money to sell things. She'd put up diets on her website. She'd take money which she said would go to charities and all sorts of cons.

[00:14:58] She had a book that came out, a cookery book that was published, and then suddenly people realised, hang on, for a start they followed the money trail and they found out that she wasn't giving money to charities. Then they started looking at what she was saying about her medical case and things that just didn't make sense. So it turned out that she's a fake. She never had brain cancer. She never had any of the conditions. She's a con artist and apparently has been a con artist for a while. And of course, you know, there's a TV show that came out on Netflix called Apple Cider Vinegar, which tells all about her story. Well, she'll sound guilty of the fraud of the charity cases, the financial.

[00:15:27] Okay, now the issue is that there's a lot of other influencers out there who are basically selling snake oil and all sorts of things like that. False cures, false hope is what they're selling. And it is false hope because you can look at it and see that the evidence is very poor. A study looked at TikTok users and they found that 87% of people who are aged between say teens and 40, especially women, it is in this particular case, as was Bill Gibson's audience, 87% get a lot of their health care, health advice from social media.

[00:15:55] And yet at the same time, roughly 2% with this study they found of the health advice on social media, only 2% aligned with public health guidelines. So there's a lot of false information out there and a lot of people following it. The trouble is the victims are victims and they're not necessarily stupid people or bright people or whatever. These are desperate people and it's sad. And you understand what their situation is and you understand how desperate they can be. Some of these people are dying, right? They'll cling to any sort of advice they get. And if you get an attractive, convincing influencer out there who says,

[00:16:25] look at me, gorgeous body, here I am in my bikini. And again, most of these influencers are women and say, this is what I did. I was sick, but here's my QE. And by the way, I will sell it to you. And they're out there. They're out there in masses of numbers and they have millions of followers. So Bill Gibson is a warning message, which should be, to other people. That's Tim Mendham from Australian Skeptics.

[00:16:46] And that's the show for now.

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