S26E01: How Spiral Galaxies Lose Their Arms // Ryugu Sheds New Light on Solar System’s History // Sun Mystery Solved?

AI Transcript

[0:01] 00:00:00.504" data-end="00:00:14.817">This is Space Time Series 26 Episode 1, full broadcast on the 2nd of January 2023. 0:08">Coming up on Space Time, how spiral galaxies lose their arms, the asteroid Raegu sheds
00:00:22.370">0:15">new light on the solar system's history, and solar orbiters solves one of the Sun's 0:21">great magnetic mysteries.
00:00:30.157">0:23">All that and more coming up on Space Time. 0:27">Welcome to Space Time with Stuart Gary.

[0:30] 0:46" data-start="00:00:30.160" data-end="00:00:45.520">Music.

[0:47] 00:00:46.919" data-end="00:00:58.163">A new study suggests that spiral galaxies, like our Milky Way galaxy for example, 0:52">to lose their spiral arms when they lose the molecular gas needed for star formation.
00:01:09.146">0:59">The findings, reported in the Monthly Notices of the Royal Astronomical Society, are based 1:03">on new computer simulation tools using artificial intelligence to accelerate their learning.
00:01:24.729">1:10">Ever since the Hubble Tuning Fork, sometimes referred to as the Hubble Sequence, which 1:14">classifies galaxy morphologies was invented back in 1926, astronomers have been refining 1:20">understanding of galaxy evolution and morphology as technology advances.
00:01:25.296" data-end="00:01:31.436">For example, by the 1970s, scientists had confirmed that lone galaxies 1:30">tend to be spiral-shaped.
00:01:43.400">1:32">However, those found in galaxy clusters were more likely to either be 1:36">spherical and featureless, what we refer to as elliptical galaxies, 1:40">or flat, lens-shaped lenticular galaxies.
00:01:55.084">1:44">And the new AI computer simulations may finally have vented the decades-long 1:49">debate about exactly how spiral galaxies evolve to become either ellipticals or lenticulars.
00:02:01.417">1:56">The simulations are showing there's a whole bunch of different things going on when lots 2:00">the galaxies get packed together.

[2:02] 00:02:02.097" data-end="00:02:11.343">It seems the spiral arms in galaxies are really fragile, 2:06">and as you get higher densities in galaxy clusters, 2:09">spiral galaxies start to lose their gas.
00:02:18.832">2:12">And this loss of gas causes them to drop their spiral arms, 2:16">transforming them into lenticular galaxies.
00:02:19.337" data-end="00:02:31.202">On the other hand, when two similar mass galaxies merge, 2:23">as the Milky Way and M31 Andromeda will do in around 4 billion years time, 2:27">they'll coalesce to form a single large elliptical galaxy.
00:02:42.247">2:32">To reach these findings, the study utilized the powerful Eagle simulations to analyze a group of galaxies in detail, 2:39">using AI algorithms to classify galaxies by their shape.

[2:43] 00:02:51.097">The neural network-based algorithm can classify about 20,000 galaxies per minute, 2:48">compressing what typically would have taken weeks into just an hour.
00:03:04.168">2:52">And the results of those simulations closely match what's actually been observed in the real universe, 2:58">giving researchers the confidence to use the simulation results 3:01">to interpret observations of galaxy clusters.
00:03:11.802">3:05">But the studies also identified several inticular galaxies 3:08">outside of the high density regions where they're expected to be found.
00:03:12.342" data-end="00:03:17.869">And here the modeling suggests that they were also created 3:15">by the merging of two separate galaxies.
00:03:18.391" data-end="00:03:32.647">One of the study's authors, Kenji Beke, 3:20">from the University of Western Australia node 3:23">of the International Centre for Radio Astronomy Research, 3:26">says there's been lots of suggestions over time, but this is the first work to put all 3:30">the pieces of the puzzle together in a single package.
00:03:39.898">3:33">So in this work we try to identify galaxies in the supercomputer simulation.

[3:41] 00:03:40.607" data-end="00:03:49.953">So in this simulation we produce many southern galaxies and then try to classify galaxies 3:46">into elliptical galaxies and spiral galaxies and then ticular galaxies.
00:03:50.647" data-end="00:03:55.847">3:51">So range-guided galaxies are very interesting objects because they don't have any spiral arms.

[3:57] 00:03:56.876" data-end="00:04:09.974">And this galaxy can be found in cluster environment or group environment. 4:03">And on the other hand, spiral galaxy can be found mostly in the field environment where 4:08">the density of galaxy is very, very low.

[4:11] 00:04:10.926" data-end="00:04:19.175">For a key question of the Hubble sequence is why the H-Pillar galaxy can be found mostly 4:17">in the group or cluster environment.
00:04:20.066" data-end="00:04:36.774">And this paper discuss this origin. 4:22">And what conclusions did the simulations show? 4:25">So simulations show for the very first time that lenticular galaxies can be formed through 4:32">gas stripping or galaxy merging in a group and cluster environment.
00:04:42.995">4:37">So you've got these spiral galaxies. 4:39">The spirals are very delicate, aren't they? 4:41">And lots of gas there.
00:04:43.326" data-end="00:04:56.534">That's when new stars are being formed. 4:45">These galaxies, for some reason, are losing their spiral arms and becoming lenticular? 4:50">So spiral arms can keep their spiral arms due to star formation within the gut.

[4:58] 00:04:58.173" data-end="00:05:09.966">So spiral arms are composed mostly of young stars. 5:02">If the spiral actually loses their gut, they can no longer form stars, so spiral arms gradually 5:10">disappear.

[5:11] 00:05:11.307" data-end="00:05:22.461">So spiral galaxy can be transformed into lenticular galaxy without any spiral arm. 5:18">So gas is very important for the maintenance of spiral arm in galaxy.
00:05:23.037" data-end="00:05:25.089">So this is a kind of a basic physics.
00:05:34.037">5:26">So in a cluster environment, spiral galaxy can lose their gas by stripping, 5:32">what we call ram pressure stripping.
00:05:42.842">5:35">So, land pressure slipping is caused by interaction between cold gas within the disk and hot gas in the cluster.

[5:44] 00:05:44.138" data-end="00:05:57.164">So, when the gas galaxy can lose gas, they can also lose their power. 5:49">So, there's got to be a galaxy cluster nearby and that's drawing the cold gas from within 5:55">the galaxy itself. 5:56">Yes, yes, yes.
00:06:09.877">5:58">So, the key physical process is the slipping of cold gas. 6:02">cold gas can form stars so if the star formation cannot continue, spiral galaxy can lose their.

[6:11] 00:06:10.992" data-end="00:06:26.926">Spiral arm. I guess the other side of the Hubble fork in this case would be elliptical galaxies and 6:17">I take it that's pretty well understood now it's merging of spiral galaxies that causes them to 6:22">convert into elliptical galaxies what we're going to become in five billion years from now. Yeah so,
00:06:27.237" data-end="00:06:30.707">So okay, the galaxy matter can create a different type of galaxy.
00:06:31.557" data-end="00:06:40.654">6:32">If the mass ratio of two galaxies is larger than 0.3, the two spiral galaxies can be transformed 6:39">into the elliptical galaxies.

[6:42] 00:06:41.771" data-end="00:06:48.306">But the mass ratio of the two galaxies is very small, like 0.1. 6:46">These two galaxies can become the S-galaxies.

[6:49] 00:06:49.277" data-end="00:06:54.491">So the first one is major mergers. 6:53">Second one is minor mergers.
00:07:02.116">6:55">So major measure can create elliptical reaction, 6:59">but minor measure can create ester reaction.
00:07:07.157">7:03">And this minor measure can happen 7:05">in a field or a small group of reaction.

[7:09] 00:07:08.717" data-end="00:07:16.141">So that's a transformation process from spiral into S0 7:13">in a small group or a field environment.
00:07:22.083">7:17">So there are two physical mechanism of ester formation. 7:20">One is gas lifting in a cluster.
00:07:25.810">7:23">The other is minor matter in a field of small groups.

[7:27] 00:07:27.295" data-end="00:07:41.636">So there are two ways of losing the fire arm. One is just slipping, the other is minor merger. 7:35">And there is a very important distinction between minor and major mergers in galaxy transformers.
00:07:55.305">7:42">So when we see things like the Sagittarius dwarf galaxy being slowly stripped into the Milky Way, 7:48">is that considered a minor merger? It's a minima. That's the mass ratio of the Sagittarius dwarf,
00:08:03.736">to the middle way is too small, less than 0.1. So it's such matter cannot damage the,
00:08:04.305" data-end="00:08:04.907">Galactic disk.
00:08:05.411" data-end="00:08:18.986">Okay. 8:07">So yeah, it's too small. Yeah. It's like mini matter. 8:10">When you put this artificial intelligence program together, were you looking at a particular 8:15">epoch of the universe? I mean, today or 10 billion years ago?
00:08:19.185" data-end="00:08:22.470">We can apply this AI to any red ship.

[8:23] 00:08:23.307" data-end="00:08:29.591">So for this paper, we use AI to classify a galaxy for the red ship zero, the present reverse.
00:08:29.789" data-end="00:08:36.928">8:30">This is one of the innovations of this paper because our AI can classify a galaxy, one 8:35">thousand galaxies within one second.
00:08:37.657" data-end="00:08:50.377">8:38">That's a huge innovation. 8:39">So so far, Astronomers have to spend one minute or two minutes per galaxy to classify a galaxy, 8:46">But for this AI, it takes only one second for one thousand years.
00:08:51.065" data-end="00:09:01.000">This is the most innovative part of this paper. 8:54">That's astronomer Kenji Becky from the University of Western Australia node of the International 8:59">Centre for Radio Astronomy Research.
00:09:03.034">And this is space time.
00:09:12.685">9:04">Still to come, the asteroid Ryugu sheds new light on the solar system's history and 9:09">Solar Orbiter solves one of the sun's great magnetic mysteries.
00:09:13.065" data-end="00:09:16.105">All that and more still to come on Space Time.

[9:16] 9:31" data-start="00:09:16.400" data-end="00:09:31.440">Music.

[9:31] 00:09:41.780">Scientists studying samples returned to Earth from the asteroid Ryugu have found that it's 9:37">composed of some of the first solid material in our solar system.
00:09:42.386" data-end="00:09:53.726">The material is known as Ivernotype carbonaceous chondrites, and it's named after the Iverna 9:48">meteorite which landed near Iverna in Tanzania back on December 16, 1938.
00:09:54.346" data-end="00:10:00.334">Iverna is one of only nine known meteorites classified as Ci1 carbonaceous chondrites.
00:10:12.298">10:01">And these all have compositions very similar to that of the Sun, meaning they're essentially 10:05">unaltered since they were formed about the same time as the solar system itself, some 10:10">4.6 billion years ago.

[10:13] 00:10:13.036" data-end="00:10:24.892">Put simply, that means they're some of the most chemically primitive meteorites known. 10:18">The designation Ci1 means that Iwuna underwent a high degree of chemical change due to the presence of water.
00:10:25.586" data-end="00:10:34.038">10:26">This alteration took place in the parent body of the meteorite at low temperatures, probably 10:30">around 20 to 50 degrees Celsius in a water-rich environment.
00:10:43.401">10:35">By contrast, chondrites experience thermal metamorphism under dry conditions, 10:40">usually at temperatures between 600 and 900 degrees Celsius.
00:10:54.374">10:44">The findings reported in the journal Nature Astronomy show that nearly two years after 10:49">Japan's Hayabusa-2 mission returned samples of the asteroid Ryugu to Earth,
00:11:00.334">10:55">scientists are continuing to reveal valuable new information 10:58">about the early history of the Solar System.
00:11:07.266">11:01">In this particular study, scientists were looking at the isotopic composition 11:05">of zinc and copper within Ryugu.
00:11:14.890">11:08">It was these isotopic signatures that showed that Ryugu's composition 11:11">was close to Iverna-like carbonaceous chondrites.

[11:16] 00:11:15.683" data-end="00:11:22.353">By the way, Ryugu-like material from the outer Solar System 11:19">accounts for about 5 to 6 percent of the Earth's mass.
00:11:28.266">11:23">So we're finding out not just about the Solar System itself, 11:26">but also about our own planet.
00:11:34.560">11:29">Meteorites found on Earth give scientists access to samples 11:32">representing the first moments of the solar system.
00:11:42.572">11:35">However, the return to Earth in December 2020 11:38">of the Japanese space agency's Ibusatou mission 11:41">provided much more than that.
00:11:43.086" data-end="00:11:53.586">It gave scientists five grams of pristine Ryugu fragments, 11:48">pieces of another world which have been completely unaltered 11:51">since their arrival and stay on Earth.

[11:55] 00:11:54.609" data-end="00:12:02.855">The first analysis showed that some isotopic signatures, including titanium and chromium, 12:00">overlap with other groups of carbonaceous chondrites.
00:12:03.089" data-end="00:12:09.066">So the details of the link between Ryugu and Avuna-like carbonaceous chondrites wasn't fully understood.
00:12:18.906">12:10">Zinc and copper are two moderately volatile elements, 12:13">and they're key to studying the process of a creation of volatiles during the formation of terrestrial planets.

[12:20] 00:12:19.761" data-end="00:12:30.203">The different groups of carbonaceous chondrites showed distinct copper and zinc isotopic compositions, 12:26">with iverna-like carbonaceous chondrites being more enriched in volatile elements.
00:12:41.429">12:31">So by carrying out the additional analysis of the copper and zinc isotopic compositions of Ryugu, 12:36">scientists wound up with access to a crucial tool for studying the origin of the asteroid.
00:12:51.665">12:42">They found that the isotopic ratios of copper and zinc in the samples of Ryugu 12:47">were identical to carbonaceous chondrites, but different from all other types of meteorites.
00:12:52.479" data-end="00:13:05.627">By finally confirming the similarity between Ryugu and carbonaceous chondrites, the study 12:58">establishes that these primitive samples of this asteroid represent the best estimate 13:03">for the solar composition to date for copper and zinc.
00:13:06.219" data-end="00:13:20.787">The 900-metre-wide asteroid Ryugu is classified both as a near or near-Earth object and as 13:12">the potentially hazardous asteroid of the Apollo group of asteroids whose orbit takes 13:16">them inside Earth's orbit around the Sun for at least part of their journey.
00:13:21.174" data-end="00:13:27.679">And that makes them pieces of space rock worth studying. 13:26">This is space time.
00:13:38.954">13:28">Still to come, Solar Orbiter solves one of the Sun's great mysteries and later in the 13:32">science report, researchers use artificial human embryos to study how the human spine is created.
00:13:39.319" data-end="00:13:42.199">All that and more still to come on Space Time.

[13:42] 13:57" data-start="00:13:42.480" data-end="00:13:57.360">Music.

[13:57] 00:14:08.484">New data obtained by the European Space Agency's Solar Orbiter spacecraft has found compelling 14:04">new clues about the origins of one of the Sun's great magnetic mysteries known as magnetic
00:14:18.504">switchbacks and how their formation accelerates the solar wind, the stream of charged particles 14:14">flowing out from the Sun which encompass and bathe the Earth.
00:14:20.103">Solar switchbacks are weird.
00:14:24.541">14:21">They're a sudden and large deflection of the solar wind's magnetic field.
00:14:25.144" data-end="00:14:34.144">Observations by Solar Orbiter provide scientists with a first full view of the structure, confirming 14:31">the hypothesis that it has an S-shaped character.

[14:35] 00:14:35.155" data-end="00:14:42.064">But it doesn't stop there, the findings also showed that these rapidly changing magnetic 14:39">fields have their origins near the Sun's surface.
00:14:51.206">14:43">While a number of spacecraft have flown through these puzzling regions before, in situ data 14:47">has only previously ever been measured at a single point in time.
00:14:58.462">14:52">Consequently, the structure and shape of the switchbacks had to be inferred from plasma 14:56">and magnetic field measurements taken at just one point.
00:14:59.224" data-end="00:15:09.201">When the German and American Helios 1 and 2 spacecraft flew close to the Sun back in 15:04">the mid-1970s, Earth probes recorded sudden reversals of the Sun's magnetic field.
00:15:19.932">15:10">These mysterious reversals were always abrupt and always temporary, lasting from just a 15:15">few seconds to a number of hours before the magnetic field switched back to its original direction.

[15:21] 00:15:20.664" data-end="00:15:28.268">These magnetic structures were also probed at much larger distances from the Sun by NASA's 15:25">Ulysses spacecraft in the late 1990s.
00:15:37.054">15:29">But instead of a third of Earth's orbital radius from the Sun, where the Helios missions 15:33">made their closest pass, Ulysses operated mostly beyond Earth's orbit.

[15:38] 00:15:50.693">The amount of data available, however, has risen dramatically with the arrival of NASA's Parker Solar Probe in 2018. 15:45">Parker showed that sudden magnetic field reversals were far more numerous close to the Sun,
00:15:56.220">15:51">and that led to suggestions that they were being caused by S-shaped kinks in the magnetic field itself.
00:16:06.978">15:57">And it was this puzzling, the still hypothetical behavior, which earned the phenomenon the name switchbacks. 16:03">A number of ideas were then proposed to try and explain how they formed.
00:16:07.491" data-end="00:16:18.402">Early last year, Solar Orbiter was just a day away from its close pass of the Sun, 16:13">well within the orbit of the planet Mercury, 16:15">and it was imaging the Sun's outer atmosphere known as the corona.
00:16:24.767">16:19">The particles in the corona are electrically charged, 16:21">and they follow the Sun's magnetic field lines out into space.
00:16:25.289" data-end="00:16:34.840">As Solar Orbiter was imaging the corona, 16:28">it recorded a distorted S-shaped link in the coronal plasma, 16:31">looking suspiciously like a possible solar switchback.

[16:35] 00:16:35.434" data-end="00:16:47.147">Later comparisons of visible light and extreme ultraviolet images of the event confirm this hypothesis. 16:42">Usually active regions are associated with sunspots and magnetic activity.
00:16:57.147">16:48">And further analysis showed the speed of the plasma above this region was actually very slow, 16:52">as would be expected from an active region that's yet to release stored energy.
00:17:07.023">16:58">The observations of the plasma resembled a generating mechanism for the switchbacks, 17:02">an idea first proposed by Gary Zank from the University of Alabama in Huntsville.
00:17:18.780">17:08">The hypothesis was looking at the way different magnetic regions near the Sun's surface interact with each other. 17:13">Close to the Sun, especially above active regions, there are closed and open magnetic field lines.

[17:19] 00:17:19.437" data-end="00:17:27.386">The closed lines are loops of magnetism which arch up into the solar atmosphere 17:24">before curving around and disappearing back deep into the Sun.
00:17:35.758">17:28">Now very little plasma can escape into space above these field lines, 17:32">so the speed of the solar wind around this area tends to be really slow.
00:17:36.254" data-end="00:17:44.086">But open field lines are the reverse, emanating from the Sun 17:40">and ultimately connecting with the interplanetary magnetic field lines of the solar system.
00:17:51.476">Figure them as magnetic highways, along which plasma can flow freely 17:49">and give rise to very fast solar wind.
00:17:52.007" data-end="00:17:58.903">The switchbacks seem to occur where there's an interaction between the region of open 17:56">field lines and a region of closed lines.
00:17:59.567" data-end="00:18:10.336">18:00">It seems as the field lines crowd together, they tend to reconnect into more stable configurations. 18:06">Magnetic reconnection is a bit like cracking a whip as it releases lots of energy at the,
00:18:15.260">18:11">same time setting up an S-shaped disturbance traveling off into space.
00:18:20.878">18:16">And it's this S-shaped disturbance passing the spacecraft, which is then recorded as a switchback.
00:18:21.527" data-end="00:18:27.332">18:22">The key observation here was that the switchbacks could be seen emanating from above an active 18:26">solar region.

[18:28] 00:18:28.067" data-end="00:18:34.174">Late last year, Solar Orbiter made a gravity-assist flyby of Venus in order to adjust its orbit 18:33">around the Sun.
00:18:49.136">18:35">And subsequent Venus flybys will now start raising the inclination of the spacecraft's 18:39">orbit, allowing it to access higher latitudes of the Sun, heading more towards the Sun's 18:44">little understood polar regions, where more mysteries are waiting to be solved.

[18:50] 00:18:50.047" data-end="00:18:57.407">This report from ACTV. 18:53">Solar Orbiter will help answer fundamental questions about the Sun's activity.
00:19:07.527">After some 20 years of development, six years of construction and more than a year of testing, 19:04">engineers have had the challenging task of designing a mission to make detailed observations,
00:19:13.073">19:08">of the Sun, capture the closest ever pictures of our nearest star and the first images of,
the poles.
00:19:14.306" data-end="00:19:20.590">The spacecraft has a number of key new technologies that have been developed just for the purpose of flying close to the sun.

[19:22] 00:19:21.625" data-end="00:19:34.480">We have a specific heat shield designed just for solar orbiter that will reach temperatures 19:26">of over 500 degrees centigrade on the front side and will keep things as cool as just 19:31">about 50 degrees centigrade on the back side to protect the sensitive electronics.

[19:36] 00:19:35.727" data-end="00:19:47.732">The sun generates a bubble of plasma enveloping the entire solar system. 19:40">as the heliosphere, anything within it, including Earth, is subject to a stream of charged particles 19:46">called the solar wind.

[19:50] 00:19:49.586" data-end="00:20:00.155">Violent space weather from flares and coronal mass ejections has the potential to damage 19:55">satellites, disrupt communications and knock out power grids on the ground.
00:20:11.182">20:01">One of the key questions the scientists have is how the heliosphere is actually generated 20:07">and how it's accelerated, so what is really driving the solar winds.
00:20:28.098">20:12">And the second key question of the mission is understanding what makes the sun change 20:17">or vary over this 11-year cycle that we all know. So understanding the magnetic properties 20:24">of the Sun and how this changes over this 11-year cycle is one of the key scientific,
00:20:29.592">objectives of Solar Orbiter.
00:20:30.466" data-end="00:20:43.186">To measure the magnetic environment around the Sun, Solar Orbiter is fitted with a suite 20:35">of 10 extremely sensitive instruments. And so it can take pictures, the heat shield has 20:40">peep holes through it, covered by protective doors.

[20:44] 00:20:44.068" data-end="00:20:54.406">We are going to places where no other solar telescopes have been before. 20:47">We are going to be very close to the Sun to take very high resolution images of the Sun, unprecedented spatial resolution.
00:21:05.340">And we are also going to fly over the poles of the Sun, regions that are very much unknown because we don't see them very well from Earth, 21:01">but they are the source of the fast solar wind and therefore are very important.
00:21:06.006" data-end="00:21:12.218">Solar Orbiter will take several years, using the gravity of Venus and Earth to reach its operational orbit.
00:21:20.406">21:13">But once in position, the spacecraft will take measurements that complement NASA's 21:17">Parker Solar Probe, which launched in 2018.
00:21:21.130" data-end="00:21:28.683">We will not get as close to the sun, but we will have vastly bigger payload complements, 21:26">so more instruments with more cameras looking at the sun.
00:21:29.206" data-end="00:21:35.030">So we will do science that is complementary to solar probe and the two will really have 21:34">a great deal of synergy.

[21:36] 00:21:36.038" data-end="00:21:56.666">This is Space Time. 21:53">And time now to take a brief look at some of the other stories making news in Science.

[21:37] 21:52" data-start="00:21:37.200" data-end="00:21:52.080">Music.

[21:57] 00:22:00.266">This week with a science report.
00:22:08.077">Have used artificial human embryos to study how a lump of tissue will elongate and form 22:06">segments creating a spine.
00:22:15.018">22:09">A report in the journal Nature claims scientists created the embryo surrogates from pluripotent 22:14">stem cells.
00:22:32.419">22:16">These differentiated artificial human embryos when exposed to specific chemical signals. 22:22">The authors are using these artificial human embryos to model human congenital spine diseases 22:27">such as scoliosis by disrupting the organism's artificial spines development.

[22:34] 00:22:33.932" data-end="00:22:48.741">The British medical journal has been slammed by scientists and medical practitioners around 22:38">the world after publishing a meta-analysis study which wrongly claimed that acupuncture 22:44">helped relieve lower back and pelvic pain often experienced during pregnancy.

[22:49] 00:22:49.334" data-end="00:22:58.679">Dr Steve Novella from Science Based Medicine criticized the analysis, saying the study 22:54">clearly showed that acupuncture didn't work other than as a placebo.
00:22:59.261" data-end="00:23:09.013">He says the authors of the study still tried to spin it the other way. 23:04">He questioned how the authors could have reached their conclusions based on the scientific 23:08">data they published.
00:23:17.926">23:10">Novella says the meta-analysis was based on just 10 studies. 23:14">Most of those studies weren't blind, which would have disqualified them immediately.
00:23:18.321" data-end="00:23:23.264">And none of the studies were double-blinded, which is the accepted standard for scientific research.
00:23:23.781" data-end="00:23:33.526">23:24">The British Medical Journal's analysis also glossed over studies with unfavorable results. 23:30">Two of the studies it did include had a greater than 20% dropout rate.
00:23:40.026">23:34">The people dropped out because the acupuncture wasn't working, meaning those left were skewing 23:39">the results.
00:23:49.929">23:41">Neville says the studies were showing publication bias, with the scientifically stronger more 23:46">rigorous studies which showed less support for acupuncture given less attention, while,
00:23:50.321" data-end="00:23:57.284">the scientifically weaker, less rigorous studies which were more supportive of acupuncture 23:55">given far greater prominence.
00:24:03.468">23:58">Importantly, the meta-analysis also failed to show which acupuncture points were being used.

[24:04] 00:24:04.062" data-end="00:24:16.980">That's important because different acupuncture practitioners use different locations on the body 24:09">because there's no agreement between practitioners about where the acupuncture points are actually 24:14">meant to be, or for that matter what each point does.
00:24:17.467" data-end="00:24:25.921">None of the studies shown in the meta-analysis use the same acupuncture points. 24:22">Avila says that's because they don't really work so it doesn't matter.
00:24:26.568" data-end="00:24:39.612">24:27">It's worth pointing out that the organisations behind these studies in the meta-analysis 24:31">were the Ku Ming Municipal Hospital of Traditional Chinese Medicine 24:35">and the third affiliated hospital of the Yunnan University of Chinese Medicine.
00:24:45.905">24:40">And the entire study was funded by the Traditional Chinese Medicine Bureau of Guidan Province.

[24:47] 00:24:47.435" data-end="00:24:56.482">A new study has found that Australian baby boomers, those born in the 1950s and 60s, 24:53">are still the most likely to use cannabis were it legal.
00:25:06.340">24:57">The findings reported in the Journal of Drug and Alcohol Review looked at the cannabis use 25:02">of some 160,000 Australians aged between 18 and 79.
00:25:16.782">25:07">The authors found favourable attitudes towards cannabis use have increased over time, moreso 25:12">in children of the 1950s and 60s than among older or younger generations.
00:25:17.269" data-end="00:25:24.939">However, the study also found that children of the 90s are beginning to catch up when 25:22">it comes to their willingness to try cannabis were illegal.

[25:26] 00:25:26.478" data-end="00:25:33.023">Ouija boards have been with us for over a hundred years now, becoming especially popular 25:31">for teenagers in movie scripts everywhere.
00:25:37.587">25:34">And of course they also make an appearance in real life, especially around Halloween.
00:25:38.198" data-end="00:25:47.998">While most see it as harmless fun, just to pile a game a while away the hours, others 25:43">swear by the board's ability to communicate with those who have passed across to the other side.
00:25:48.444" data-end="00:25:55.173">But Tim Mendham from Australian Skeptics says what the true believers are really seeing 25:53">is something called the idiomotor effect.
00:26:03.549">In your youth when you do a séance as you do with your mates, you darken the room, you 26:01">stick a few candles around. 26:02">I've been there, done that, yeah. Yeah, you often set up a homemade Ouija board, right?
00:26:03.773" data-end="00:26:07.773">26:04">Well, you write the letters on a bit of paper and you put those around the table, really yes, no.
00:26:07.773" data-end="00:26:17.773">26:08">So it doesn't have to be the upmarket, expensive wooden Ouija boards. 26:11">They were actually made, a lot of them, by Hasbro, which makes a lot of board games,
00:26:24.013">26:18">by the way, and with a little plonchette thing, a little wooden thing that you did with wheels 26:22">that you put your fingers on and then moves around.
00:26:36.813">So, you know, we're just supposed to be channeling spirits who then can read out particular suggestions 26:30">by going through a letter and spelling out a word or going to yes or no or goodbye actually, 26:35">if here's one of the options as well.
00:26:40.828">26:37">So you've got a yes and no and then lots of letters around and that's the way you spell out a message.

[26:41] 00:26:41.093" data-end="00:26:45.333">And lo and behold, someone's discovered that people might be manipulating this. 26:44">Oh no!
00:26:51.333">I'm the one who usually did that. 26:47">Yes, didn't we all? 26:49">And you think, and then you get the argument, no, I didn't push it.
00:26:57.333">Did you push it? No, I didn't push it. 26:53">What they're suggesting is not even consciously pushing, 26:55">it might be unconsciously pushing.
00:27:02.333">And this is the suggestion that it's something called the idiomotor effect, 27:00">which is brain over physics, if you like.
00:27:10.333">Your brain subconsciously wants something to happen, so it manipulates what you do. 27:06">It's often used as an explanation for how divining rods, dousing rods,
00:27:21.248">the little sort of bent stick or the bent bit of wire or something, 27:13">bit of wire or something, why they move and why they cross over etc. But if you look at 27:17">people who are using those things, their hands tend to move a little bit, only a tiny bit,
00:27:25.733">because these things are way off center of balance, so a tiny movement subconsciously,
00:27:30.773">27:26">can move dividing rods and the same thing can apply to moving this little planche around.
00:27:43.173">27:31">That's not accounting for the fact that some people are pushing it on purpose like you and me. 27:35">Yeah, unconsciously people who are sincere might be moving down to a particular result, 27:40">but probably you get a lot of people who are sincere all doing the same thing at the same time.
00:27:56.933">They're probably going to get a very sort of a weird result spelling out words that don't exist. 27:48">They're moving all over the place. Of course, they often move quickly and you don't have to push 27:52">very hard on these things, these things to move. And so practical joke, idiom motor effect,
00:27:57.059" data-end="00:28:01.333">not necessarily spirits is basically what this article is saying and I would agree with that.
00:28:03.874">That's Tumendam from Australian Skeptics.

[28:05] 28:20" data-start="00:28:05.360" data-end="00:28:19.760">Music.

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00:30:01.044">You've been listening to Space Time with Stuart Gary. 29:57">This has been another quality podcast production from Bitesz.com.