S27E141: Black Hole Banquet, Uranus' Magnetic Squeeze, and Earth's Shifting Surface

[00:00:00] This is SpaceTime Series 27 Episode 141 for broadcast of the 22nd of November 2024.

[00:00:06] Coming up on SpaceTime, a black hole found to be consuming matter faster than its theoretical limit, solving another one of the many mysteries of the planet Uranus, and a new spacecraft designed to track how Earth's surface moves.

[00:00:21] All that and more coming up on SpaceTime.

[00:00:26] Welcome to SpaceTime with Stuart Gary.

[00:00:45] Astronomers have discovered a supermassive black hole in the early universe that's consuming matter more than 40 times faster than its theoretical limit.

[00:00:54] The discovery of this black hole, apparently feasting on material at an extreme rate just one and a half billion years after the Big Bang,

[00:01:01] is providing scientists with valuable new insights into the mechanisms of rapidly growing black holes in the early universe.

[00:01:09] Supermassive black holes exist at the centers of most, if not all, galaxies.

[00:01:13] And modern telescopes are continuing to find them at surprisingly early times in the universe's evolution.

[00:01:20] But until now, it's been really difficult to understand how these black holes have been able to grow so big so quickly.

[00:01:27] The black hole, catalogued as LID 568, was discovered using the Webb Space Telescope, which was observing a sample of galaxies from the Chandra X-ray Observatory's Cosmos Legacy Survey.

[00:01:39] This population of galaxies are very bright in X-rays, but are invisible in optical and near-infrared.

[00:01:46] But Webb's unique infrared sensitivity allowed the telescope to detect these faint counterpart emissions.

[00:01:52] LID 568 stood out within the sample for its intense X-ray emissions,

[00:01:57] but its exact position couldn't be determined from the X-ray observations alone.

[00:02:01] And that raised concerns about properly centering the target within Webb's field of view.

[00:02:07] So, rather than using traditional slit spectroscopy, scientists decided to use the integral field spectrograph on Webb's near-infrared spectrometer.

[00:02:16] This instrument can get a spectrum from each pixel in its field of view, rather than being limited to just a narrow slice.

[00:02:22] It allowed the authors to get a full view of their target and its surrounding region,

[00:02:27] leading to the unexpected discovery of powerful outflows of gas around the central black hole.

[00:02:32] The speed and size of these outflows led scientists to infer that a substantial fraction of the mass of LID 568

[00:02:40] may have occurred in a single episode of rapid accretion.

[00:02:43] In a stunning discovery, they found that LID 568 appears to be feeding on matter at a rate more than 40 times its Eddington limit.

[00:02:53] Now, the Eddington limit relates to the maximum luminosity that a black hole can achieve,

[00:02:58] as well as how fast it can absorb matter, such that its inward gravitational force

[00:03:02] and outward photon pressure generated from the heat of the compressed inward-falling material remains in balance.

[00:03:08] It's possible that the powerful outflows observed in LID 568 may be acting as a sort of release valve

[00:03:15] for the excess energy generated by the extreme accretion, preventing the system from becoming too unstable.

[00:03:22] The study's lead author, He-Won Su from the National Science Foundation's National Optical Infrared Astronomy Research Laboratory,

[00:03:29] says these serendipitous results add a new dimension to science's understanding of the system

[00:03:33] and open up exciting new avenues for future investigation.

[00:03:37] The findings reported in the journal Nature show how this extreme case demonstrates that a fast-feeding mechanism above the Eddington limit

[00:03:45] is one of the possible explanations for why we see so many large supermassive black holes

[00:03:50] so early in the history of the universe.

[00:03:53] It means the results are providing new insights into the formation of supermassive black holes from smaller black hole seeds,

[00:04:00] which current theories suggest arise either from the death of the universe's first stars or from the direct collapse of giant gas clouds.

[00:04:08] Until now, these theories lacked any observational confirmation.

[00:04:12] Su says the discovery of a super-Eddington-accreting black hole suggests that a significant proportion of the mass growth of the black hole

[00:04:20] can occur during a single episode of rapid feeding, regardless of how the black hole originated.

[00:04:25] This is space-time.

[00:04:27] Still to come.

[00:04:29] Solving one of the many mysteries of the planet Uranus.

[00:04:32] And a new spacecraft to launch next year to track how the Earth's surface moves.

[00:04:37] All that and more still to come on Space-time.

[00:04:55] Astronomers have discovered that an unusual space weather event literally squeezed the planet Uranus's magnetic field,

[00:05:02] dramatically compressing its magnetosphere, just before NASA's Voyager 2 spacecraft flew past it in 1986.

[00:05:10] The new findings, which were revealed while astronomers were mining 38-year-old data from Voyager 2,

[00:05:15] helps explain the ice giant's weird magnetic field at the time of the flyby.

[00:05:20] Voyager 2 has provided scientists with their first and so far only close glimpse of this strange, sideways rotating outer planet.

[00:05:29] Alongside the discovery of new moons and rings, baffling new mysteries about Uranus confronted the Voyager scientists.

[00:05:36] They discovered the energized particles around the planet defied their understanding of how magnetic fields work to trap particle radiation.

[00:05:44] And that earned Uranus a reputation as an outlier in our solar system.

[00:05:49] The study's lead author, Jamie Jaszinski from NASA's Jet Propulsion Laboratory in Pasadena, California,

[00:05:55] says that if Voyager 2 had arrived just a few days earlier, it would have observed a completely different magnetosphere around Uranus.

[00:06:02] Instead, the spacecraft saw Uranus in conditions that actually only occur about 4% of the time.

[00:06:09] Magnetospheres serve as protective bubbles around planets with magnetic cores and magnetic fields,

[00:06:15] shielding them from the ionized gas or plasma that streams out from the sun and the solar wind.

[00:06:21] Learning more about how these magnetospheres work is important both for understanding our own planet,

[00:06:26] as well as those in seldom visited corners of our solar system and beyond.

[00:06:30] That's why scientists were eager to study Uranus's magnetic field,

[00:06:34] and what they saw in the Voyager 2 data back in 1986 flummoxed them so badly.

[00:06:40] Inside Uranus's magnetosphere were electron radiation belts with an intensity

[00:06:44] second only to Jupiter's notoriously brutal radiation belts.

[00:06:49] Problem is, there was no apparent source of energized particles to feed those active belts.

[00:06:54] In fact, the rest of Uranus's magnetic field was almost devoid of plasma.

[00:06:58] The missing plasma also puzzled scientists because they knew that the five major Uranian moons in the magnetic bubble

[00:07:05] should have produced water ions as icy moons around other planets do.

[00:07:09] They therefore concluded that the moons must be inert with no ongoing activity.

[00:07:14] So, why was no plasma observed, and what was happening to beef up the radiation belts?

[00:07:19] The new data analysis reported in the journal Nature Astronomy points to the solar wind.

[00:07:25] When plasma from the Sun pounded and compressed the magnetosphere, it likely drove plasma out of the system.

[00:07:31] And the solar wind would also briefly intensify the dynamics of the magnetosphere,

[00:07:36] which would have fed the belts by ejecting electrons into them.

[00:07:39] And the findings could be good news for those five major moons of Uranus,

[00:07:43] some of which might be geologically active.

[00:07:46] With an explanation for the temporarily missing plasma, researchers say it's plausible that the moons actually may have been spewing ions into the surrounding bubble all along.

[00:07:56] Planetary scientists are focusing on bolstering their knowledge of the mysterious Uranus system,

[00:08:00] which is being prioritized as a target for a future NASA mission.

[00:08:04] As for the Voyager 2 spacecraft, while it's still operational, currently flying through unexplored interstellar space,

[00:08:11] some 21 billion kilometers from Earth.

[00:08:14] This is space-time.

[00:08:17] Still to come, scientists are developing a new satellite designed to measure ground movement on the Earth's surface.

[00:08:22] And later in the science report, the World Meteorological Organization says 2024 is on track to become the hottest year on record.

[00:08:30] All that and more still to come on Space Time.

[00:08:48] Scientists are developing a new satellite designed to measure ground movement on the Earth's surface.

[00:08:54] The joint NASA Indian Space Research Organization synthetic aperture radar, or NISA, mission,

[00:09:00] will measure the motion of nearly all of the planet's land and ice-covered surfaces twice every 12 days.

[00:09:06] The joint US-Indian satellite will track the Earth's changing surface,

[00:09:10] improving science's understanding of phenomena like earthquakes, volcanoes and landslides.

[00:09:15] Now, other satellites have monitored ground movement before,

[00:09:18] but the pace of NISA's data collection will give researchers a more fuller picture of how the Earth's surface changes over time.

[00:09:26] The probe will also help people prepare for and recover from natural and human-caused disasters.

[00:09:31] NISA applications lead Kathleen Jones from NASA's Jet Propulsion Laboratory in Pasadena, California,

[00:09:37] says this kind of regular observation will allow scientists to look at how the Earth's surface moves across nearly the entire planet,

[00:09:44] providing a more complete picture both horizontally and vertically.

[00:09:48] Targeted for launch from India early next year,

[00:09:50] the mission will be able to detect surface motions down to centimetres and map changes in vegetation.

[00:09:56] It uses a pair of radar instruments that operate at long wavelengths,

[00:10:00] an L-band system built by JPL and an S-band system built by ISRO.

[00:10:05] And NISA will be the first satellite to carry both.

[00:10:08] Each instrument can collect measurements day and night,

[00:10:11] and they can see through clouds that would normally obstruct the view of optical instruments.

[00:10:16] The L-band instrument will also be able to penetrate dense vegetation to measure ground motion.

[00:10:20] This capability will be especially useful in areas surrounding volcanoes or fault lines that are often obscured by vegetation.

[00:10:28] This report from NASA TV.

[00:10:32] Infrastructure problems are common around the world.

[00:10:35] NISAR is a new Earth-observing mission to image all of the land across the globe.

[00:10:41] This is a partnership between NASA and the Indian Space Research Organization.

[00:10:45] The thing that's really cool about this instrument is that you can do interferometry,

[00:10:50] looking at how the surface is moving so that you can tell where something might be going wrong.

[00:10:57] Is this getting close to failure?

[00:11:00] For example, if a landslide is slipping, then put your ground attention on that point.

[00:11:06] In 2015, the airport had a major slope failure.

[00:11:09] That created a huge interruption to their operations and damaged their safety overrun area.

[00:11:14] And then we designed the replacement wall at the end of the runway.

[00:11:17] We have instrumentation in the wall.

[00:11:19] We'll be using NISAR to monitor the wall deformations and the surrounding area in the future.

[00:11:25] So when we think about the application of NISAR to a project like this,

[00:11:29] how does that feed into the overall mitigation?

[00:11:32] So I think the goal is to be able to use NISAR data as that early warning system.

[00:11:37] It'll give us an alert that something is starting to move,

[00:11:39] hopefully within plenty of time, to take action to assess the problem and take remediation before it becomes a problem.

[00:11:46] This instrument is going to give you an idea of what's happening over the whole system.

[00:11:51] So in the context of dams or levees, you can look at whether the slope of the dam is somehow shifting.

[00:11:59] We're interested in NISAR data because it'll provide us a good amount of information on a variety of our projects.

[00:12:06] We have over 700 dams in our inventory.

[00:12:08] We also have over 2,000 miles of levee.

[00:12:11] The Corps' responsibility is to make sure that it's functional and keeping people safe downstream should a flood event occur.

[00:12:17] The main purpose of our projects is for water supply, hydropower and flood control.

[00:12:22] It's really difficult to monitor every point on every project, but NISAR will provide us good coverage of a lot of projects that are difficult to get to in remote areas that are very large.

[00:12:34] And we can use that to supplement our existing monitoring programs to see are there any areas that we need to look at more closely,

[00:12:41] add additional instrumentation, basically as a screening level tool to see are there areas that we should be looking at that we're not already.

[00:12:47] This is like the culmination of a dream to be able to have this instrument operating and providing this kind of data for everywhere.

[00:12:56] And in their report from NASA TV, we heard from Alan Cadden, Principal with Schnabel Engineering,

[00:13:01] Ben Webster, who's also with Schnabel Engineering,

[00:13:04] and Georgette Helapis, Principal Geotechnical Engineer with the US Army Corps of Engineers.

[00:13:10] This is Space Time.

[00:13:27] And time now to take another brief look at some of the other stories making news and science this week with the Science Report.

[00:13:34] The World Meteorological Organization says 2024 is now on track to be the hottest year on record.

[00:13:41] The findings released at the COP29 climate change conference in Baku, Azerbaijan,

[00:13:46] follow an extended streak of exceptionally high monthly global average temperatures.

[00:13:50] The authors say the latest WMO State of the Climate 24 update once again puts the world on red alert

[00:13:57] at the sheer pace of climate change in a single generation.

[00:14:01] They say the increase in global temperatures is being caused by ever increasing greenhouse gas levels in the atmosphere.

[00:14:08] The 10 years from 2015 to 2024 will be the warmest decade on record.

[00:14:13] The loss of ice from glaciers, sea level rise and ocean heating are accelerating

[00:14:18] and extreme weather is wreaking havoc on communities and economies across the world.

[00:14:23] The World Meteorological Organization says China remains the world's biggest carbon dioxide polluter,

[00:14:29] producing over a third of the world's total output.

[00:14:32] That amounts to over 10.2 million tonnes annually.

[00:14:37] A new study has shown that ultra-processed foods are now dominating diets globally.

[00:14:42] The findings presented to the International Congress on Obesity suggest that ultra-processed foods

[00:14:48] are increasing their share of diets of people worldwide,

[00:14:50] and that's despite the known risks they come with.

[00:14:54] The study's authors say processed foods are already making up almost half of Australian diets.

[00:14:59] Ultra-processed foods have been linked to at least 25 chronic diseases,

[00:15:03] and the authors are now recommending that ultra-processed foods should be regulated

[00:15:07] in the same way as tobacco products.

[00:15:11] A new study has shown that so-called toy dog types, bred for companionship,

[00:15:16] have bigger brains relative to their body size, while working dogs tend to have smaller brains.

[00:15:21] Researchers measured the volumes inside some 1,700 skulls in 170 different dog breeds

[00:15:27] as an indicator of brain size.

[00:15:29] They found that they correlated to several behavioural traits.

[00:15:33] Dog breeds that were more fearful, aggressive and attention-seeking tended to have the largest brains

[00:15:38] compared to their body size, while highly trainable breeds tended to have smaller brains relative to body size.

[00:15:45] The findings reported in the journal Biological Letters shows how mammals' brain sizes are changeable

[00:15:51] with domestication and artificial selection.

[00:15:55] Back in 1996, NASA carried out a fascinating experiment to generate electricity from their ionosphere

[00:16:02] using a small satellite tethered to a space shuttle.

[00:16:05] The experiment aboard the space shuttle Columbia during mission STS-75

[00:16:09] saw the deployment of the satellite using a conductive tether attached to the shuttle.

[00:16:14] The tether satellite system circled the Earth at an altitude of 296 kilometres,

[00:16:19] placing the tether system within the rarefied, electrically charged layer of the ionosphere.

[00:16:25] Now, the electric conductor of the tether was a copper braid wound around a gnomic string.

[00:16:30] It was all encased in Teflon insulation with an outer cover of Kevlar inside a nylon sheath.

[00:16:37] Scientists hoped to deploy the tether out to a distance of 20.7 kilometres.

[00:16:41] Over five hours, some 19 kilometres of tether was reeled out.

[00:16:46] But then, all of a sudden, the tether snapped,

[00:16:49] producing numerous pieces of floating debris through plasma discharge

[00:16:52] as well as the rupture of the tether itself.

[00:16:55] The culprit turned out to be the innermost core,

[00:16:57] which was made of a porous metal which, during its manufacture,

[00:17:01] trapped bubbles of air at atmospheric pressure.

[00:17:03] Later vacuum chamber experiments suggested that the unwinding of the reel

[00:17:08] uncovered pinholes within the insulation.

[00:17:10] Now, that in itself would not have caused a major problem,

[00:17:13] because the ionosphere around the tether, under normal circumstances,

[00:17:17] would have been too rarefied to divert much of the current.

[00:17:20] However, the air trapped within the insulation changed that.

[00:17:23] As the air bubbled out of the pinholes,

[00:17:26] the high 3,500 volts of the nearby tether converted it into a relatively dense plasma,

[00:17:32] making it a much better conductor of electricity.

[00:17:34] And this plasma diverted to the metal of the shuttle

[00:17:37] and from there to the ionospheric return circuit.

[00:17:40] That current was enough to melt the cable.

[00:17:43] Well, that's the science.

[00:17:45] However, UFO fans have come up with a very different takeaway message.

[00:17:50] And of course, it involves alien life.

[00:17:52] But Tim Mindham from Australian Skeptic says,

[00:17:55] astronauts, including one involved in the experiment,

[00:17:58] say they've never seen any evidence of alien life.

[00:18:00] So this satellite launched and the tether of the rope that's connecting it to the,

[00:18:04] like an umbilical cord connecting it to the space shuttle,

[00:18:07] apparently broke, snapped.

[00:18:08] And the astronaut who was actually on that space shuttle,

[00:18:11] his name was Tom Jones.

[00:18:12] That's not unusual.

[00:18:14] That's not unusual.

[00:18:15] He said, no, all these things that were around it,

[00:18:18] everyone was saying it's all UFOs interested in the satellite,

[00:18:20] et cetera, little spots and dots and blobs.

[00:18:23] He was saying that this readiness to suggest a UFO alien extraterrestrial

[00:18:28] explanation for things is pretty common.

[00:18:30] And the astronauts themselves get confronted with these views quite readily.

[00:18:34] And he says, but as far as he knows,

[00:18:35] no astronauts have actually seen any evidence of alien life.

[00:18:38] And he's been up four times, I think, in the space shuttle.

[00:18:40] There is one astronaut who's sighted a lot by the UFO community

[00:18:44] and that's Edgar Mitchell, who was the sixth man to walk on the moon.

[00:18:47] And he has said that he believes in alien life

[00:18:49] and that he's seen evidence of it and UFOs and all sorts of things.

[00:18:53] And he's been going around for years, although he's passed away now.

[00:18:55] I saw him once way back when in the dim, dark, distant ages.

[00:18:59] And I was quite disappointed with him

[00:19:00] because he obviously comes from a bit of a technical background,

[00:19:03] but he was applying totally non-technical reasons to his belief.

[00:19:06] But anyway, he's been sighted many times.

[00:19:08] He's the hero, a bit of the UFO community.

[00:19:10] He's the astronaut, you know, the one who should know.

[00:19:12] But according to Tom Jones, every other astronaut,

[00:19:14] no other astronaut has ever seen any evidence of this sort of thing.

[00:19:17] Anything they've seen which is strange, they can explain.

[00:19:19] And that's the big thing is that an unidentified flying object

[00:19:22] is unidentified until someone identifies it.

[00:19:25] So, an interesting story.

[00:19:26] He was actually interviewed for the Smithsonian and put out this story.

[00:19:30] Astronauts have not seen any evidence of alien life

[00:19:32] and he used the Tether incident to actually give an example

[00:19:36] of how people misinterpreted a quite normal, explicable event

[00:19:39] that people applied alien solutions to it, alien explanations for it.

[00:19:42] Looking at what's happened to this planet over the last few centuries,

[00:19:46] any self-respecting alien life form flying past would immediately wind up the windows

[00:19:52] and lock the doors and keep on going.

[00:19:54] Yeah, yeah.

[00:19:54] They wouldn't hang around here.

[00:19:55] No, it's a bad neighborhood.

[00:19:56] That's Tim Mendham from Australian Skeptics.

[00:20:00] And that's the show for now.

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