[00:00:00] This is SpaceTime Series 27 Episode 61 for broadcast on the 20th of May 2024.
[00:00:06] Coming up on SpaceTime, a spectacular solar storm stuns the world, unusual activity in Earth's
[00:00:13] magnetodale, and scanning the skies for neutrinos from deep under the sea.
[00:00:20] All that and more coming up on SpaceTime.
[00:00:24] Welcome to SpaceTime with Stuart Gary.
[00:00:27] The Sun has produced its biggest solar flare in nearly two decades.
[00:00:48] The massive 8.7-class explosion rounded off more than a week of spectacular geomagnetic storms,
[00:00:55] which pummeled the Earth and created dazzling northern and southern auroral lights powerful
[00:01:00] enough to reach mid-latitude skies normally unaccustomed to seeing such spectacles.
[00:01:05] NASA's Solar Dynamics Observatory captured the bright blast,
[00:01:09] which was the strongest solar flare since 2005 and the biggest during the Sun's current 11-year
[00:01:14] solar cycle. The event is being classified as an extreme geomagnetic storm, the first since
[00:01:21] the Halloween storms of October 2003, which caused blackouts in Sweden and damaged power
[00:01:26] infrastructure in South Africa. The solar cycle is a nearly periodic 11-year change in the Sun's
[00:01:32] activity measured in terms of variations in the number of observed sunspots on the Sun's surface.
[00:01:38] Over the period of the solar cycle, levels of solar radiation and ejection of solar material,
[00:01:44] the number and size of sunspots, solar flares and coronal loops all exhibit a synchronized
[00:01:49] fluctuation from a period of minimum activity known as solar minimum to a period of maximum
[00:01:54] activity known as solar maxima or solar max for short and then back to a period of minimum activity
[00:02:00] again. The Sun's magnetic field flips polarity during each solar cycle, with the star's magnetic
[00:02:07] north pole becoming south and its south pole becoming north. This flip occurs at solar max.
[00:02:14] After two solar cycles, the Sun's magnetic field returns to its original state, completing what's
[00:02:19] known as a hail cycle. The current solar cycle, number 25, began back in December 2019 and
[00:02:26] appears to be happening unusually quickly, with solar max likely to occur a year earlier than
[00:02:31] expected. The good news is the powerful X8.7 class solar flare which erupted last week was
[00:02:37] facing away from the Earth as sunspots which spawned it were rotating over the Sun's western
[00:02:43] or right-hand limb. The flare was caused by a cluster of sunspots known as Active Region 3664.
[00:02:50] The cluster was around 17 times as wide as the planet Earth itself, and it was by far the largest
[00:02:56] and most complex solar sunspot region observed during the current cycle. Starting around May 8,
[00:03:03] Active Region 3664 sent at least seven solar flares and coronal mass ejections racing towards
[00:03:09] the Earth, often reaching speeds of up to 1,800 km per second, and they triggered the most intense
[00:03:15] geomagnetic storms or space weather events of the current solar cycle. Space weather is a sudden
[00:03:21] flood of energy and ionized particles, such as protons, electrons and atomic nuclei, triggered by
[00:03:28] powerful eruptions of solar flares and coronal mass ejections on the Sun's surface. Solar flares are
[00:03:34] explosions of energy caused by the sudden snapping of tangled and twisted magnetic field lines.
[00:03:40] These are known as flux ropes, and they emanate from sunspots on the solar surface.
[00:03:45] Sunspots are cooler regions on the Sun's surface that appear darker than surrounding areas.
[00:03:51] That's because the magnetic field lines reaching out into space from deep inside the Sun at these
[00:03:55] places prevents some of the heat from within the Sun from reaching the surface. Sunspots usually
[00:04:01] appear in pairs of opposite magnetic polarity. The number varies according to the 11-year solar cycle.
[00:04:08] There are very few, and sometimes none at all, during solar minimum, and they reach a crescendo
[00:04:13] at solar max. Individual sunspots or groups of sunspots can last anywhere from a few days to
[00:04:20] several months, but they all eventually decay. Sunspots expand and contract as they move across
[00:04:26] the surface of the Sun, with diameters ranging from 16 to 160,000 kilometers.
[00:04:33] So what's behind them? Well, different latitudes of the Sun rotate at different rates, causing these
[00:04:38] magnetic field lines to become tangled and twisted, eventually snapping and then realigning
[00:04:43] through magnetic reconnection. And that produces secondary phenomena such as coronal loops,
[00:04:48] prominences and eruptions of electromagnetic energy which, if facing the Earth, can reach
[00:04:53] the planet in just 8.3 minutes. Now, if the solar flares are powerful enough, they'll also drag
[00:04:59] billions of tons of coronal plasma and embedded magnetic field frozen as flux with them, exploding
[00:05:05] out into space at speeds of up to 3,000 kilometers per second, which, if facing the Earth, will reach
[00:05:11] our planet in just 15 to 18 hours. When these geomagnetic storms reach the Earth, the flux of
[00:05:17] ionized particles slam into our planet's magnetosphere and they're then guided by the planet's
[00:05:22] magnetic field lines through the ionosphere, a region already filled with charged particles,
[00:05:26] and then down towards the north and south magnetic poles. Now, as these charged streams of plasma
[00:05:33] travel through the Earth's upper atmosphere, they collide with oxygen and nitrogen atoms and molecules,
[00:05:38] causing them to excite and emit photons, giving off a glow and producing colorful
[00:05:43] cone-like displays known as the northern and southern lights, the aurora borealis and aurora
[00:05:48] astralis. The colors being emitted by these lights depends on which particles are being ionized.
[00:05:55] Reddish brown glows are caused by the collision of particles with single oxygen atoms in the Earth's
[00:06:01] upper atmosphere, usually above 300 kilometers. Lower down, a green hue is created by single
[00:06:07] oxygen atoms down to altitudes of around 100 kilometers. The kaleidoscope then turns a whiteish
[00:06:12] yellow beige when nitrogen is mixed in with the oxygen. Aurora also exhibit a blue, red, or even
[00:06:18] purple glow in the lower atmosphere caused by the excitation of molecular nitrogen below 100 kilometers.
[00:06:25] However, as well as the spectacular aurora light shows, these highly charged particles can also
[00:06:30] cause a lot of damage, even destroying spacecraft by shorting out electronics and damaging circuits.
[00:06:36] They also cause the Earth's atmosphere to expand and contract, wobbling like jello,
[00:06:41] and that increases atmospheric drag on orbiting spacecraft, resulting in premature orbital decay
[00:06:47] and the need to use up more fuel in order to maintain an operational orbit.
[00:06:51] Worse still, space weather increases the level of radiation exposure astronauts experience,
[00:06:56] affecting their health. On the ground, these solar storms can overload power lines,
[00:07:01] blowing transformers, and causing widespread blackouts. In 1989, one such geomagnetic storm
[00:07:07] blew out a whole bunch of transformers, causing massive blackouts across eastern North America.
[00:07:13] Geomagnetic storms also affect communications and navigation satellites. But satellite operators,
[00:07:19] electrical grid managers, and engineers who maintain crucial technological infrastructure
[00:07:23] say while they're still assessing the impact of this historic event, most major systems
[00:07:28] seem to have weathered the blast okay. Although New Zealand's electrical transmission services
[00:07:33] did temporarily turn off some circuits around the country to prevent equipment damage.
[00:07:38] As a precaution, NASA temporarily stopped gathering astronomical data from its Chandra
[00:07:42] X-ray Observatory and stowed its instruments in order to protect them from the radiation blasts.
[00:07:48] And the agency's ICESat-2 spacecraft suddenly shut down when it experienced unexpected rotation
[00:07:53] during the storm, probably caused by increased atmospheric drag. The agency says however there
[00:07:59] was no threat to crew aboard the International Space Station and Beijing says their Tiangong
[00:08:04] space station also remained operational. But concerns like that were far from the minds of
[00:08:09] the general public, with the northern and southern lights at their best and social media being
[00:08:15] flooded with stunning images. Normally restricted to polar regions and higher latitudes, the auroral
[00:08:21] light show was visible all the way south to Mexico and the Bahamas, and north as far as Tasmania,
[00:08:26] Melbourne, Perth and Adelaide. Now the cause of all this, Active Region 3664 has now rotated off
[00:08:33] the side of the sun seen from Earth and entered the field of view of the European Space Agency's
[00:08:38] solar orbiter which is in the middle of a series of dives through the sun's outer atmosphere and
[00:08:43] will undoubtedly provide a new perspective on all the activity. And NASA's Parker Solar Probe
[00:08:48] spacecraft, which is currently at the outer part of its looping orbit around the sun, will also be
[00:08:53] able to provide some unique data. And it doesn't end there. For two of NASA's Mars spacecraft, the
[00:08:59] solar storm provides an unprecedented opportunity to study how intense solar activity hits the red
[00:09:05] planet. NASA's Mars Atmosphere and Volatile Evolution spacecraft MAVEN monitored the
[00:09:11] geomagnetic storm's effects on the red planet's atmosphere while the agency's Curiosity rover in
[00:09:16] Gale Crater studied those same effects from the ground. For the record, the most powerful geomagnetic
[00:09:22] storm in recorded history was the Carrington event, named after British astronomer Richard Carrington.
[00:09:28] It peaked around the first and second of September in 1859 during what was solar cycle 10. It created
[00:09:35] strong auroral displays that were reported globally and caused sparking and even fires at multiple
[00:09:41] telegraph stations. A geomagnetic storm of that magnitude occurring today would cause widespread
[00:09:47] electrical disruptions, power blackouts and other damage due to extended outages of the electrical
[00:09:52] grid. But it's not all over yet folks. We're getting our first glimpse of a new active sunspot
[00:09:58] region. This one's been named 3685, which is now rotating into view around the eastern or left-hand
[00:10:04] limb of the sun. And it's already erupted in major X-class solar flares, including one X2.99 event.
[00:10:12] It certainly looks like the upcoming solar max will be really interesting. This is Space Time.
[00:10:19] Still to come, unusual activity in the Earth's magnetotail and scanning the skies for neutrinos
[00:10:26] from deep under the sea. All that and more still to come on Space Time. Astronomers have detected
[00:10:48] an unusual event in Earth's magnetotail, the elongated portion of the planet's magnetosphere
[00:10:53] trailing away from the sun. The data from NASA's Magnetospheric Multiscale Mission spacecraft are
[00:10:59] showing fleeting disturbances in the magnetotail known as substorms that are releasing energy and
[00:11:04] triggering auroral activity. Since their launch in 2015, the four spacecraft have been surveying
[00:11:10] the magnetopause, the boundary between the magnetosphere and surrounding plasma. They're
[00:11:15] looking for signs of magnetic reconnection, which happens when magnetic field lines converge, break
[00:11:21] apart and then reconnect explosively, converting magnetic energy into heat and kinetic energy.
[00:11:26] In 2017, they observed signs of magnetic reconnection in the magnetotail, but not the
[00:11:32] normal signs of a substorm that accompany reconnection, such as strong electrical
[00:11:36] currents and perturbations in the magnetic field. One of the scientists involved in the study,
[00:11:41] Amy Marshall from the Southwest Research Institute in San Antonio, Texas, says scientists want to
[00:11:46] see how the local physics observed by the probes affects the entire global magnetosphere.
[00:11:52] By comparing that event to more typical substorms, scientists are striving to improve their
[00:11:57] understanding of what causes a substorm and the relationship between substorms and magnetic
[00:12:02] reconnection. During this year-long project, scientists will compare in-situ measurements
[00:12:07] of magnetic reconnection affecting local fields and particles to global magnetosphere
[00:12:12] reconstructions created by NASA's Goddard Space Flight Center using space weather computer modeling.
[00:12:18] Marshall says it's possible significant differences exist between the global
[00:12:22] magnetotail convection patterns for substorms and non-substorm tail reconnection.
[00:12:27] Researchers haven't yet looked at the movement of magnetic field lines on a global scale,
[00:12:32] so it could be that this unusual substorm was a very localized occurrence that the spacecraft
[00:12:37] just happened to be lucky enough to observe. On the other hand, if not, it could completely
[00:12:42] reshape science's understanding of the relationship between tailside magnetic
[00:12:47] reconnection and substorms. Needless to say, we'll keep you informed.
[00:12:52] This is Space Time. Still to come, scanning the skies for neutrinos from deep under the sea.
[00:12:59] And later in the Science Report, new observations have now confirmed that April 2024 was the
[00:13:05] hottest month on planet Earth ever recorded. All that and more still to come on Space Time.
[00:13:27] China has started construction of the Deep-Sea Neutrino Telescope in the Western Pacific.
[00:13:32] The Tropical Deep-Sea Neutrino Telescope, or TRIDENT, will search for, detect, and analyze
[00:13:38] neutrinos in order to study the origins of cosmic rays and explore the extreme universe.
[00:13:44] Neutrinos are elementary subatomic particles. They're generated through radioactive decay
[00:13:50] in stars, in supernovae, in nuclear explosions, in particle accelerators, and in atomic reactors.
[00:13:57] The neutrino is so named because it's electrically neutral and because its rest
[00:14:01] mass is so small it was long thought to be zero. Neutrinos are the most common form of
[00:14:06] matter in the universe and having almost no mass, they're capable of being accelerated to
[00:14:11] almost the speed of light. They come in three known types or flavors, electron neutrinos,
[00:14:17] muon neutrinos, and tau neutrinos, each with its own specific properties. Now confusingly,
[00:14:23] the three flavors of neutrinos don't line up with the three mass species. It seems each of
[00:14:29] the three flavors is made up of a quantum mixture of the three mass species. So for example,
[00:14:34] a particular tau neutrino would have bits of all three mass species in it.
[00:14:39] Now those different mass species allow the neutrino to oscillate between the three flavors.
[00:14:44] For example, an electron neutrino produced in let's say a beta decay reaction could end up
[00:14:49] interacting in a distant detector as a muon or tau neutrino. Now although they have no electrical
[00:14:55] charge, neutrinos do have their own corresponding antimatter counterparts identified by the
[00:15:00] opposite chirality or handedness. Neutrinos interact with other matter only through gravity
[00:15:06] and the weak nuclear force. In fact, they're so weakly interactive that several trillion are
[00:15:11] passing through you every second without you even realizing it. China's neutrino observatory
[00:15:16] is being built on a deep sea plane some three and a half kilometers below the surface.
[00:15:21] The detector will comprise 1,200 vertical strings or cables, each 700 meters long and spaced between
[00:15:28] 70 and 100 meters apart. Each string will carry 20 high-resolution digital optical detector modules.
[00:15:36] Spanning around four kilometers and covering some 12 square kilometers, the array will monitor
[00:15:41] around eight cubic kilometers of seawater looking for high-energy neutrino interactions.
[00:15:47] It'll be the fourth neutrino array of this type. The others include the famous IceCube
[00:15:52] Observatory on Antarctica which is the world's leading neutrino telescope, the Baikal GVD
[00:15:57] Observatory on Lake Baikal, and the Cubic Kilometer Neutrino Telescope or KM3Net located
[00:16:04] some three and a half kilometers below the surface in the Mediterranean Sea at three locations off
[00:16:09] the coast of Sicily, France, and Greece. The Cubic Kilometer Neutrino Telescope is still under
[00:16:14] construction and it includes the Astroparticle Research with Cosmics in the Abyss or ARCA
[00:16:19] telescope which will search for neutrinos from distant astrophysical sources such as supernovae,
[00:16:25] gamma-ray bursts, and colliding stars. And the Oscillation Research with Cosmics in the Abyss or
[00:16:30] ARCA telescope which is studying neutrino properties exploiting neutrinos generated
[00:16:35] in Earth's atmosphere. Arrays of thousands of optical photomultiplier sensors will detect the
[00:16:40] faint light in the deep sea from charged particles originating from collisions between neutrinos and
[00:16:46] the Earth. The facility will also include instrumentation for Earth and Sea Sciences
[00:16:51] for long-term and online monitoring of the deep sea environment and of the seafloor.
[00:16:56] Once complete, the ARCA detector will form an array of more than 200 detection units. Each of
[00:17:02] these 700 meter long cables will hold 18 modules equipped with ultra-sensitive light detectors that
[00:17:08] register the faint flashes of Cherenkov radiation generated by neutrino interactions in the pitch
[00:17:13] black abyss of the Mediterranean Sea. The position and direction of the optical modules and the time
[00:17:19] of arrival of the light on the photomultiplier's inside is recorded and the trajectories of the
[00:17:24] particles then reconstructed from these measurements. The entire cubic kilometer
[00:17:29] neutrino telescope project should be completed and fully operational by 2026, occupying more than a
[00:17:35] cubic kilometer of water comprising hundreds of vertical detection lines anchored to the seabed
[00:17:40] and held in place by buoys. One of the project scientists, Dr. Clancy James from Curtin University
[00:17:46] in the International Center for Radio Astronomy Research, says such a huge volume of water was
[00:17:51] required to surround the instruments because neutrinos would otherwise be extremely difficult
[00:17:56] to detect. James says the underwater telescope is bombarded by millions of different particles
[00:18:01] but only neutrinos can pass through the Earth to reach the detector from below, so unlike normal
[00:18:07] telescopes which look upwards into the skies, this facility looks downwards towards the Earth.
[00:18:13] Thereby seeing the same skies as viewed by upwards facing telescopes in Australia.
[00:18:18] The particles that CAM3Net is detecting, neutrinos, you know they interact very rarely and we expect
[00:18:23] CAM3Net to only detect maybe of order dozens per year. However there's also particles from
[00:18:29] these cosmic ray interactions that hit the top of the atmosphere muons and come down. So what this
[00:18:33] means is that the detector is saturated by about a million muon events a day coming down from above.
[00:18:39] However only neutrinos can actually make it up from under the detector. So the best way of saying
[00:18:45] okay we detected this particle, was it a neutrino or was it something else, is to look for particles
[00:18:51] coming up underneath, from underneath the detector coming up through the Earth at which point you
[00:18:56] can say well the only thing that could have possibly made it through the whole Earth to
[00:18:59] the detector was a neutrino. So what this means is that neutrino telescopes mostly look downwards
[00:19:05] through the Earth as opposed to normal telescopes when you point them up at the sky above you.
[00:19:09] And so the sky, the region of the universe that CAM3Net will be studying is the region of the
[00:19:14] universe that's visible from normal telescopes on the opposite side of the world. That is to say
[00:19:19] Australia which means that the sky that Australian telescopes are viewing is exactly the same sky
[00:19:23] that CAM3Net is viewing all the time. Now neutrinos are the most common type of massive, I say massive
[00:19:30] particle in the universe, particle that has mass. But they almost never interact with things. So we
[00:19:36] have something like you know 10 to the 12 passing through us every second of that order from the sun.
[00:19:41] So the neutrinos are produced in nuclear reactions. The ones we're trying to look for are produced by
[00:19:46] high energy particle interactions going on in the universe somewhere. So I'm sure you're familiar
[00:19:51] with the Large Hadron Collider and you know this atom smasher smashing together particles at you
[00:19:56] know very high energies. Well this is happening out there in the universe but at even higher energies.
[00:20:00] Now the fact that it's being positioned in the Mediterranean Sea exactly opposite where Australia
[00:20:05] is, is that deliberate or is that just a coincidence? It's a coincidence. So the reason it's there is
[00:20:10] simply because it's a collaboration of European institutes and if you want to build an instrument
[00:20:16] it's easier to do it nearby. And the main constraint you need is to get this thing down deep.
[00:20:21] You need it to be deep down in the water for two reasons. One, so it's dark. So when you do
[00:20:26] sort of an estimate of the amount of light that you get detected, so what happens is a neutrino
[00:20:30] if it does interact will produce a burst of light and that light is extremely faint. So you might
[00:20:36] only detect maybe a dozen photons from that collision which is about the amount of light
[00:20:41] that you'd get in one second from my light globe here in my office that you would see in Sydney.
[00:20:45] So it's not very much light. So you need it to be in a really dark place and you don't actually get
[00:20:50] it to be dark enough unless you're more than a kilometre under the surface of the water.
[00:20:54] The other reason is that these cosmic rays I mentioned earlier, these high energy particles
[00:20:59] from space, they're hitting the top of our atmosphere all the time and they produce
[00:21:03] more particles that then sort of rain down on us at sea level and some of these particles called
[00:21:08] muons can actually go through kilometres of stuff. They actually don't get stopped very easily at all
[00:21:14] and so what you want to do is shield yourself from as many of these muons as possible by going deeper
[00:21:19] and deeper. Now you can't shield yourself from all of them so KM3Net will detect something like
[00:21:25] a million of these muons a day but nonetheless it's much easier to do at the surface. So the
[00:21:29] reason it's being built at the bottom of the Mediterranean is that there's some sufficiently
[00:21:33] deep places there to do this experiment. Is there a reason why you've chosen liquid water rather than
[00:21:38] solid water such as the South Pole neutrino detector which is in... Yeah exactly. So yeah,
[00:21:44] so IceCube is the name of the instrument you're referring to. So that's the one that first
[00:21:48] discovered this sort of high energy flux of neutrinos coming from the universe. So the two
[00:21:53] reasons we've chosen water, one it's just practical. It's there you know when you're building, when
[00:21:58] you're putting a large amount of money into an instrument you have a trade-off between what's
[00:22:02] nearby and the most optimal site ever but the main reason actually is that it turns out that water
[00:22:08] is an excellent medium to do this in because... So the problem with water is that it absorbs more light
[00:22:13] than ice so you want to detect light from these faint neutrinos but light gets absorbed in water
[00:22:18] with a length scale of say 50 meters whereas in ice a photon might bounce around for 200 meters
[00:22:23] before it gets absorbed. However if you ever like stand on top of the snow and look into ice versus
[00:22:28] stand on top of water and look down you see further into water right and this is because
[00:22:34] water doesn't scatter light as much so what this means is when when a neutrino interacts it emits
[00:22:39] the light in a characteristic cone shape right it comes out with a cone with an opening angle
[00:22:43] of about 30 degrees this is Cherenkov radiation. That blue Cherenkov radiation light? Yep, exactly the
[00:22:49] kind of light that we're detecting. This light comes from these particles from high energy
[00:22:54] particles that have been in this case emitted by radioactivity and came through that emitted from
[00:22:59] the interaction of the neutrino and because they're going really fast through the water they emit a
[00:23:03] shock wave just like a supersonic jet emits a shock wave and that shock wave comes across in blue light
[00:23:11] whereas a supersonic jet shock wave comes across in terms of a sharp crack of sound. There's new
[00:23:16] science to be had here. Yes, exactly so the key part about KM3 now is that it's really going for
[00:23:22] a high resolution detector at the end of the day it's going to act like a telescope you're going to
[00:23:26] detect neutrinos you get some idea of how much energy they had but you want to find out where
[00:23:31] they're coming from right this is a big mystery we're trying to solve what's producing these high
[00:23:35] energy neutrinos in the universe there's a lot of ideas but we don't know the answer so in astronomy
[00:23:41] you take a telescope you point it somewhere and you see what you see right what's producing light
[00:23:46] or look at the star however the angular resolution of ice cube i mean it's not bad but it's not that
[00:23:53] great when typically maybe of order a degree or so for the best events or thereabouts and the
[00:23:59] universe is big so when you point back and say oh there's a neutrino that came from this direction
[00:24:03] what's there the answer is all sorts of things because you can't tell with enough precision
[00:24:08] where the neutrino came from so KM3 net's going to have an angular resolution of maybe five to
[00:24:13] ten times an improvement over ice cube and the idea being that you can really detect exactly
[00:24:19] where the neutrinos are coming from and be more definite about their sources better crosses to
[00:24:23] find your target exactly i'm right in thinking neutrinos are the most common substance in the
[00:24:28] universe other than photons well there's also dark matter particles that's what we don't really have
[00:24:34] that's what it's going to come to next and it's possible that neutrinos are well it's not possible
[00:24:39] neutrinos are also being considered as uh or some types of neutrinos that species not yet
[00:24:44] actually discovered are being considered as a possible candidate for dark matter yeah that's
[00:24:48] true so basically there's three let's call them normal types of neutrinos or flavors of neutrinos
[00:24:53] that are part of the standard model of particle physics so we know that these normal neutrinos
[00:24:58] can't be a dark matter they're not a dark matter candidate however there's quite a few different
[00:25:03] theories of what we call you know beyond the standard model particle physics for instance
[00:25:06] there's something called supersymmetry that predicts that for every normal particle we see
[00:25:10] there's something called a supersymmetric partner of that particle i want to go into the exact
[00:25:14] details of this mostly because i am not an expert on it and anything i say will probably be wrong
[00:25:18] however the supersymmetric partner of the neutrino or neutrino which is called is quite likely the
[00:25:25] lightest supersymmetric particle and therefore the easiest to detect so one of the goals that
[00:25:32] mostly what we're doing is detecting high energy astrophysical neutrinos from these sources that
[00:25:37] are detected called the archa detector will be detecting there's another component to km3 net
[00:25:41] which is called orca which will be a similar number of photon detectors but compacted into
[00:25:46] a smaller volume what that's going to be doing is studying a neutrino oscillation so let's say
[00:25:50] a neutrino starts as a muon neutrino it will travel a certain distance and then it might
[00:25:54] be an electron neutrino electron neutrino or can it go from a muon to a tau and then
[00:26:01] from a tau to an electron or does that have to do in a certain sequence or they don't have to
[00:26:04] do a certain sequence however there's a certain probability yeah so there's actually there's
[00:26:10] something called a mixing matrix which tells you how one neutrino that's created with a certain
[00:26:15] flavor and then has a certain energy what the probability of it is to mix into the other
[00:26:21] neutrino flakes and this is dependent upon how far it travels and what its energy is and what
[00:26:26] its initial flavor is one thing that's worthwhile noting though is that we know there's a three
[00:26:30] flavors of neutrinos but we don't know what the heaviest ones are right this is something called
[00:26:35] the neutrino mass hierarchy problem we actually don't know what the heaviest and what the lightest
[00:26:40] kind of neutrinos are so we know the differences in their masses but of course if i tell you that
[00:26:45] the difference between object a and object b is five kilograms you don't know if a or b is heavier
[00:26:51] right you just know the difference and and we know these differences from neutrino oscillations
[00:26:58] so and there's something called the normal hierarchy or the inverted hierarchy which gives
[00:27:03] you two different possible orderings of the masses so this is something that came through
[00:27:07] and it's going to try to resolve through this sort of in this much denser detector called orca and
[00:27:12] that's going to be studying neutrinos at lower energies and it's actually studying neutrinos
[00:27:16] that are produced by the cosmic rays hitting the atmosphere and it's going to try to work out
[00:27:20] the mass ordering you know weighing the masses of the most common particle in the standard model
[00:27:25] i'd say most common technically photons i think are more common but yeah so this is the other goal
[00:27:30] of k-m3 that is the two key science goals of the lower energy what we call atmospheric neutrinos
[00:27:35] because of the cause they come from the cosmic ray interactions with neutrinos in the atmosphere
[00:27:39] and using these neutrinos to understand the mass ordering of neutrinos and if that measurement that
[00:27:45] may turn up something that isn't consistent with the standard model of particle physics right as
[00:27:50] possible we could get hints of the dark matter candidate there and then the other aspect is
[00:27:54] looking at the high energy astrophysical neutrinos where we'll be studying neutrinos from
[00:27:58] these particle collisions in the vicinity of black holes or exploding stars and that's going to tell
[00:28:04] us about the sort of most violent and powerful processes in the universe one of the most
[00:28:09] fascinating things about the explosion of supernova 1987a was that the neutrinos arrived slightly
[00:28:14] before the visible light and that's because the visible light had to travel through all the
[00:28:20] turbulence and and refuse and debris of the supernova explosion itself whereas neutrinos
[00:28:25] being so weakly interactive just traveled in a straight line exactly yeah so it's interesting
[00:28:31] that people think of new of supernova as these optically bright things but actually most of
[00:28:36] the energy in a supernova gets emitted as neutrinos so a supernova is basically a neutrino
[00:28:41] explosion that has this tiny optical signature and i love that because that is exactly the right
[00:28:45] definition one thing worth noting is that the neutrinos that we detected from supernova 1987a
[00:28:52] and the sun are at much lower energies than the neutrinos that km3 net will be studying so the
[00:28:57] lowest energy neutrinos that came through net will be studying are merely a thousand times more
[00:29:01] energetic than the neutrinos we detect from you know the solar neutrinos and the highest energy
[00:29:07] ones will be more like a million times as energetic or perhaps even a billion times as energetic
[00:29:12] actually when i think about it being so far down in the ocean i guess you don't have to worry about
[00:29:16] things like storms and that sort of stuff but what about the uh just the uh the dust and uh
[00:29:22] or some dust is it at work just the um the tight detritus that's uh floating down there at that
[00:29:29] depth is that a problem for the detectors yes so actually there's a whole lot of oceanographic
[00:29:35] physics oceanographic science that i had no idea existed and now do because i'm working with km3
[00:29:42] the other thing to note by the way is that came through and had a predecessor instrument
[00:29:46] antares which is still functioning but it's only about two percent the size of what came
[00:29:50] through net will be so we know exactly how it's going to operate because of our experience with
[00:29:55] this previous instrument so uh in terms of our experience with this thing this this stuff you're
[00:30:02] talking about the detritus one of the official names of this is gelbstoff um so yellow stuff
[00:30:07] in german and this is also known as marine snow so one of the problems is that this sometimes
[00:30:13] accumulates on the top of your light detectors right and will block them what you find though
[00:30:19] is that every every now and then you get stronger undersea currents because there's still currents
[00:30:25] in the ocean even down at two and a half kilometers and so what you can do is you can say well as time
[00:30:30] goes on more and more of this marine snow accumulates on the top of your instruments
[00:30:34] so the light detectors that are facing upwards get a bit less sensitive and a bit less sensitive
[00:30:37] then there's a period where there's a higher oceanographic current it washes the detectors
[00:30:41] clean and then your sensitivity goes up again and then time goes on and it slowly gets less
[00:30:46] sensitive and then there's another high current event and washes it clean so you see all these
[00:30:50] sort of interesting effects in your instrument from the ocean floor here one of the other
[00:30:54] interesting things you do is that you're throwing a detector into the ocean the way it's set up is
[00:30:59] that the optical detectors are held on um on strings these are very long pieces of mostly
[00:31:05] nylon cable let's say 700 meters long and there's current these currents i mentioned will cause
[00:31:11] these strings to sway in the ocean now when you detect this light signature of a neutrino
[00:31:16] you need to know where your detectors were when they detected it so you can reconstruct the direction
[00:31:20] neutrino came from so what you do is you use acoustic pingers and sensors so you have some
[00:31:25] pingers that say go ping from known locations on the seabed and then you have detectors which will
[00:31:29] listen for this and then you can measure it by measuring the distances from the pinger to the
[00:31:33] acoustic receiver you can find out you know where your instrument is so okay that's a technical
[00:31:39] detail the cool thing about this is that it means you hear everything else going on in the ocean
[00:31:44] whale song, shrimps doing... and so you can actually use this yeah you can use this detector
[00:31:50] to track sperm whales and because you've got an array of many many of these receivers there's
[00:31:55] actually ocean science groups that use the data from what to me is just a calibration instrument
[00:32:00] to actually track the feeding patterns of sperm whales and say you know what times a day they're
[00:32:06] feeding because these things can dive down almost a kilometer or more deep into the ocean it's
[00:32:09] amazing so i think it might be even a kilometer and a half or so um to huge depths and what they
[00:32:14] do is when they're hunting squid they have a sonar that pings off the front of the whale and then
[00:32:20] you can also see this ping go forward that you can detect you also get a reflection off the back of
[00:32:24] the whale skull so by measuring the time between the initial sort of while ping if you like and
[00:32:30] the reflection you can get an estimate for the size of the whale so there's all sorts of fascinating
[00:32:35] studies you could do. That's Dr Clancy James from Curtin University and the International Center
[00:32:40] for Radio Astronomy and Research. This is Space Time.
[00:32:48] And time now to take a brief look at some of the other stories making use in science this week
[00:33:04] with the Science Report. New observations have confirmed that April 2024 was the hottest month
[00:33:10] on record and the 11th consecutive month of record heat. The European Union's Copernicus
[00:33:16] Climate Change Service made the observations based on both surface and satellite data which
[00:33:21] confirmed that April 2024 was globally warmer than any previous April dating back to 1940.
[00:33:28] It was also 1.58 degrees Celsius warmer than the estimated average for pre-industrial levels.
[00:33:35] It follows a string of record hot months starting from the hottest June on record last year.
[00:33:40] Global warmings added 1.25 degrees Celsius to global average temperatures since pre-industrial
[00:33:45] times and the El Nino added an additional quarter of a degree on top of that. Overall,
[00:33:51] the data shows that planet Earth is warming by roughly 0.25 degrees Celsius per decade.
[00:33:57] That's up from the way it was warming 25 years ago when it was more like 0.2 degrees Celsius
[00:34:03] per decade. Meanwhile, scientists say the summer of 2023 was overall the warmest in the northern
[00:34:09] hemispheres' tropical regions for the past 2,000 years. A report in the journal Nature reconstructed
[00:34:15] the past 2,000 years of land temperature data based on tree rings and combined this with
[00:34:21] observational measurements of more recent temperature records. They found that the
[00:34:25] summer of 2023 exceeded pre-instrumental average temperatures for the years 1 to 1890 CE by 2.2
[00:34:32] degrees Celsius and was 2.07 degrees Celsius higher in the summer of 2023 than instrumental
[00:34:38] averages between 1850 and 1900 CE. A new study based on 20 years of research has now confirmed
[00:34:47] beyond any reasonable doubt that plant-based foods are better for your health than a meat-based diet.
[00:34:53] The findings reported in the journal PLOS One found that vegetarian and vegan diets are better
[00:34:59] than meaty ones for your heart health and chances of avoiding cancer. The research is based on 48
[00:35:05] individual studies, all of which were conducted since the year 2000. They found that overall,
[00:35:10] vegetarian and vegan diets were strongly linked with reduced risks of heart disease, type 2
[00:35:15] diabetes, cancer and premature death. That's because it resulted in improvements in blood
[00:35:21] pressure and blood sugar management and lower body mass index. Primary plant-based diets were
[00:35:26] linked with reduced risk of heart disease caused by arteries narrowing, gastrointestinal and
[00:35:31] prostate cancer and dying early from heart disease. However, in pregnant women they found
[00:35:36] no benefits of plant-based diets incurring gastrointestinal diabetes or high blood pressure.
[00:35:43] A new study claims that males with low levels of testosterone may have an increased risk of dying
[00:35:49] prematurely. The findings reported in the Journal of the Annals of Internal Medicine follow an
[00:35:54] investigation looking at the relationship between testosterone and other sex hormone levels together
[00:35:59] with health in aging men. The authors reviewed the results of 11 previous studies measuring the sex
[00:36:05] hormones of a total of 24,000 men using the same technique, all following up with participants for
[00:36:11] at least five years. When they reanalyzed all the data together, researchers found men with low
[00:36:16] levels of testosterone concentrations had a higher risk of dying from any cause and men with very low
[00:36:22] testosterone concentrations had a higher risk of dying due to heart problems. There's been yet
[00:36:29] another call for an investigation into the authenticity of the Shroud of Turin. The Shroud
[00:36:34] is believed by some to be the death shroud of Jesus Christ, but multiple scientific studies,
[00:36:40] including carbon dating, have conclusively proven that it was actually created in the 12th century.
[00:36:46] Tim Mendham from Australian Skeptics says it's all part of a new film which fails to provide any new
[00:36:52] evidence. Yeah, there's a bit of an industry of documentaries on the Shroud of Turin and book solid
[00:36:57] etc. It's an ongoing debate despite scientific investigations it doesn't seem to go away.
[00:37:03] Now, the Shroud of Turin is a cloth that supposedly shows that was wrapped around
[00:37:09] Jesus after the crucifixion and the story goes that for some reason his image was imprinted on
[00:37:15] the cloth okay and the cloth is now kept in the cathedral in Turin and shown every nth number
[00:37:20] of years, not very often and when it is, you get crowds coming to see it. The trouble is you can't
[00:37:25] see much because it's actually pretty faint and vague but if you take a photo of it and put it
[00:37:30] in negative, you actually see a lot more. Do we have negative photos anymore? I don't know but
[00:37:33] certainly in the old days when you took a photograph, you got a negative and that's when someone said
[00:37:37] oh there's a lot more detail here than we thought. The detail includes, it looks like blood from a
[00:37:43] crown of thorns might have left or caused, not the crown itself. It looks like holes in his hands
[00:37:48] where he would have been crucified which is not the way you were crucified at the time but never
[00:37:51] mind we'll leave that one for the time being and that he has possibly broken arms, he possibly has
[00:37:56] a spear, certainly a hole in his side where the story goes that a Roman soldier speared him which
[00:38:01] is what they used to do to kill someone off rather than just hang around there all the time being
[00:38:05] miserable. Now this story goes that when did this shroud first appear and the church did a bit of
[00:38:10] investigate, Catholic Church did a bit of investigation and found out it was really sort of about medieval
[00:38:14] days 1200 something like that and there are stories about it and some illustrations of it
[00:38:19] having been found or at least displayed and discussed around that time. There's also somewhere
[00:38:24] that there's a record of a word of warning about it saying there's this guy hoisting this shroud
[00:38:28] around as a bit of a tourist thing, a bit of a circus object and it's a fake. Now what it comes
[00:38:33] down to is, is the shroud as we know it a genuine object from the first century CE wrapped around Jesus
[00:38:41] and that shows him his image etc, his whole body image front and back or is it something that was
[00:38:45] made up a thousand years later for a bit of a tourist thing, a bit of a miracle cloth. There's
[00:38:50] been scientific investigations of it over and over and over again. Part of the problem was that at
[00:38:56] one stage the cloth was folded like you'd fold a towel or a sheet and put away and there was a fire
[00:39:02] in the place where it was being stored and some I think silver reliquaries melted onto the cloth
[00:39:08] and where it was folded it got burnt so when you unfold it, you get these little burn marks of
[00:39:13] various places around the whole shroud and they're suggesting that that might have
[00:39:16] impacted on the image. Certainly you can still see the image but you can see these burn bits
[00:39:20] pretty clearly but scientific tests, x-ray, carbon dating which is not crash site for this sort of
[00:39:26] thing but you know looking at the cloth itself, looking at any herbal or you know seeds or any
[00:39:30] residue in the cloth, looking at the historical record where it's been etc. I think it first appeared
[00:39:35] in France somewhere. A group called the Shroud of Turin Research Project had a lot of people
[00:39:40] involved. Some people have complained that some of the, it had dozens of people involved, physicists
[00:39:44] and chemists. This is the one where they took samples to different universities? That's right,
[00:39:49] at least three different universities I think to try and get carbon dating and they all came
[00:39:52] back the same or pretty close to each other as much as you can get an accuracy of carbon dating
[00:39:56] for something that old and they all came back with it being about 1200 roughly around there
[00:40:01] suggesting that the shroud is not an ancient bit of material that would have been around at the
[00:40:04] time of Jesus. It is a bit of material that was woven in 1200 and therefore the image,
[00:40:09] the suggestion therefore is the image dates from the same time. So that was the agreement that
[00:40:13] came into there. Now people are saying oh well we can't trust them. Someone is suggesting in
[00:40:16] a recent article, a recent documentary that's coming out about the shroud that you can't trust
[00:40:21] because some of the scientists were agnostics. You think well some of them were scientists.
[00:40:25] I mean which way? You only trust… One would sort of hope they were agnostics.
[00:40:29] Hope they were, yeah. You'd hope you get a mixture right of some people who were agnostics.
[00:40:33] You want someone who's not going to be biased in their reporting,
[00:40:35] in whether they carry out their study. That's exactly right and this documentary
[00:40:39] thinks only an agnostic would be biased against the shroud. Obviously those who are
[00:40:43] religious people are not going to be biased. No, they wouldn't care. An agnostic wouldn't care.
[00:40:46] That's right. Well it might be a bit sort of antagonistic to it but really if you're
[00:40:51] agnostic rather than atheist say… Exactly.
[00:40:56] …to be more equanimity. But anyway this has been going on and on and on for ages and supposedly
[00:41:00] finding new evidence. These keep popping up. There's been others that have been investigating
[00:41:03] it over the years, various things and some came back saying oh it is a real cloth or
[00:41:08] but the image is not new. It's not as old as the cloth or that cloth is not ancient,
[00:41:14] it's a thousand years old etc. etc. And it's a messy area especially if the church doesn't
[00:41:18] really like putting it out for everybody and their dog coming and taking a snip of it.
[00:41:22] Now look I'll tell you what, if it was real it'd be a pretty weird looking person to start with
[00:41:28] wouldn't he? Yes. It's a very elongated image. The arms, the forearms in particular look too long.
[00:41:35] The way it's sort of draped doesn't almost… there's two aspects. Some say someone created
[00:41:40] a statue or a carving of a man lying down, put a cloth over it, did a rubbing as you can do on
[00:41:45] church tombs and that sort of stuff. Did a rubbing with some sort of material, with some sort of
[00:41:49] chemical and did it both sides, turned him over, flipped him over, put the shroud. The shroud is
[00:41:53] in one long piece that goes from the head down to the toes and then back up again up the back. So
[00:41:58] the suggestion is that he was using a carving or an actual person, he didn't mind sitting there
[00:42:03] and being messed around with and that's so therefore some of the elongation and some of
[00:42:06] the weird things that because of the distortion from the way the cloth was draped over the
[00:42:10] person or the statue. Others would say that because the cloth is supposed… the image on the cloth is
[00:42:15] supposedly a discharge when Jesus was resurrected which is sort of the suggestion that it was,
[00:42:21] and suddenly get this image implanted on the cloth that that should be more accurate as to
[00:42:26] a physical person. I mentioned before about the holes in the hands, people who are crucified
[00:42:31] normally and crucifixion was fairly common in those days. You see Spartacus, everyone gets
[00:42:35] crucified at the end of Spartacus, that was a fairly common punishment.
[00:42:38] I'm Spartacus! No, I'm Spartacus! No, I'm Spartacus and so is my wife!
[00:42:44] The crucifixion you'd normally be tied up, rope around your arms and tied to a cross.
[00:42:49] That's nailing someone to a cross, that was certainly not common I don't think but if you're
[00:42:54] going to nail someone to a cross you have to do it through the wrist. If you do it through the hand,
[00:42:58] the palm of the hand unfortunately it tears straight through between your fingers or you
[00:43:02] pulled off, that's a bit nasty because your weight is leaning forward and your hand pulls straight,
[00:43:07] the nail goes straight through your hand or it comes out between the fingers etc.
[00:43:11] This is even nastier. You put it through the wrist and then the nail can't move because it's stopped
[00:43:15] by the hand bones, right? So the wrist is a bit of a place, if you're going to nail someone to a cross
[00:43:18] you do it through the wrist. As for nailing their feet, half the time their feet was on a platform,
[00:43:22] other times they wasn't. The way you died generally was that you suffocated because your arms are up
[00:43:27] and don't try hanging up on your arms for too long. It's not good for your chest, not good for your
[00:43:31] lungs and therefore after a few hours the person might be sort of suffering and which is when the
[00:43:36] soldier comes along and sticks a spear in your side to basically hurry things along. Now Jesus
[00:43:40] was supposed to be up there for a long time, they put him down alive, buried him in a cave,
[00:43:45] rolled the rock, unrolled the rock, he's not there etc but the shroud still works. So this is a story
[00:43:49] that's been going on for a long long time. It's interesting, it's romantic but apparently
[00:43:52] scientifically it doesn't hold up that well. But for the religious people they believe it.
[00:43:57] That's Tim Endam from Australian Skeptics.
[00:44:02] And that's the show for now. Space Time is available every Monday, Wednesday and Friday
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