Milky Way’s Hidden Neighbours Come Into View with Rubin Observatory

[00:00:00] [SPEAKER_02] This is Space Time Series 29 Episode 136 for broadcast on the 13th of November 2026. Coming up on Space Time, the Milky Way Galaxy's new neighbours, moving a step closer to the Zeptoverse, and Tasmania's eye in the sky. All that and more coming up on Space Time.

[00:00:22] [SPEAKER_01] Welcome to Space Time with Stuart Gary.

[00:00:41] [SPEAKER_02] Astronomers have discovered two hidden companions of our Milky Way Galaxy. The findings, reported in the Astrophysical Journal Letters and on the pre-pressed physics website archive.org, add to the roughly 65 known satellite galaxies orbiting our Milky Way. The new detections are based on observations by the Vera C Rubin Observatory in Chile. They include an ultra-faint galaxy called Aquarius IV, located in the Milky Way's distant

[00:01:09] [SPEAKER_02] outskirts, roughly 355,000 light years away. The other is a star cluster named Rubin GC1, located on the far side of the Milky Way, inside a murky region shrouded by cosmic dust. Large galaxies, like the Milky Way, are often orbited by smaller satellite galaxies, or sometimes just star clusters. But many of these are extremely faint and therefore difficult to find. Astronomers speculate that hundreds more Milky Way satellite galaxies are out there,

[00:01:38] [SPEAKER_02] yet to be detected. One of the study's authors, William Cerny from Yale University, says these discoveries are just the beginning for the new Vera C Rubin telescope, and point to a wave of discoveries that may complete the census of the Milky Way's neighbouring galaxies, including its faintest companions. Cerny says if this new observatory can find systems this faint and difficult with only its preview data, its full 10-year survey mission will undoubtedly provide many more Milky Way satellite

[00:02:05] [SPEAKER_02] discoveries, giving astronomers new opportunities to test models of galaxy formation, trace the assembly history of the Milky Way, and investigate the nature of dark matter. The Vera C Rubin Observatory only began its 10-year legacy survey of space and time in June. The observatory uses an 8.4-meter survey telescope, and features the largest digital camera ever built, 3.2 gigapixels. One of its main

[00:02:31] [SPEAKER_02] missions is to map what's known about the Milky Way's halo, a cloud-like sphere of gas, dust, stars and dark matter that surrounds the main part of the galaxy. In the process, finding previously hidden satellite galaxies, star clusters and other substructures. Beyond the significance of these new discoveries themselves, the authors say their findings may provide valuable information about the nature of dark matter, that mysterious invisible substance thought to act like a scaffold which supports most of the

[00:03:00] [SPEAKER_02] matter in our universe. This is space-time. Still to come, physicists move closer to understanding the Zeptoverse and Tasmania's eye in the sky, the Greenhill Observatory. All that and more still to come, on Space-time. After a search lasting some 42 years, physicists have finally found evidence of a particle

[00:03:26] [SPEAKER_02] decay so rare that it's only expected to occur around once in every 10 billion bottom or beauty quark particles. The discovery at the world's large atom smasher, CERN's Large Hadron Collider beneath the Franco-Swiss border, brings physicists a step closer to exploring what they term the Zeptosphere, an unexplored world that exists at distances of a billionth of a trillionth of a metre, or a zeptometer, a region where new particles

[00:03:51] [SPEAKER_02] and forces of nature may be hiding. Quarks are subatomic elemental particles found inside protons and neutrons in the nucleus of atoms. There are six types, up, down, top, bottom, sometimes called beauty, charm and strange. The new findings will allow scientists to better understand the standard model of particle physics, the foundation stone of our understanding of the universe, which describes the

[00:04:16] [SPEAKER_02] fundamental particles and their interactions. It'll allow scientists to search for signs of new physics that may lie beyond the standard model. The research was carried out at the collider's LHCb experiment, which studies particles containing beauty quarks. Beauty quarks are produced in huge numbers in collisions at the LHC, but exist for only around one and a half trillionth of a second before decaying. By making precise measurements of the different ways beauty quarks decay, physicists can detect the

[00:04:45] [SPEAKER_02] influence of new particles that may be far too small to see at the Large Hadron Collider. The rarer the decay is, the more sensitive it can be to the influence of new particles, and these particles could alter how often the decay occurs. The new result concerns an especially rare decay known as Bd to µµ, in which a particle containing a beauty quark decays into two muons, heavier relatives of electrons. Scientists predict this only happens around once in every 10 billion beauty

[00:05:14] [SPEAKER_02] particles, and until now no single experiment has found solid evidence of the process. The new measurement reached a statistical significance of 3.2 sigma. That's sufficient for physicists to describe the result as the first evidence of the decay, although further data will be needed to reach the 5 sigma threshold required to claim a discovery in particle physics. The authors hope measurements like

[00:05:38] [SPEAKER_02] this could allow them to probe the Zepto universe. Increasingly precise measurements of these rare decays could help physicists search for signs of new physics and reveal where the standard model might eventually begin to break down. One of the study's authors, Connor Fitzpatrick from the University of Manchester, says there's been a more than 40-year-long search by physicists worldwide to observe this decay. He says it's a golden channel to observe the effects of new physics from beyond our current knowledge.

[00:06:07] [SPEAKER_02] See, the standard model of particle physics explains a lot of the universe. But it doesn't explain everything. It can't explain dark matter or dark energy, two of the biggest mysteries dominating science today. This is space-time. Still to come, Tasmania's eye in the sky, the Greenhill Observatory, and later in the Science Report, a new study warns that being born preterm is linked to poorer cognitive performance in early adulthood.

[00:06:35] [SPEAKER_02] All that and more still to come on Space Time. Sitting on a peak about 70 kilometres north of Hobart is Tasmania's most advanced link to the cosmos.

[00:07:00] [SPEAKER_02] The Greenhill Observatory and its telescopes and antennae enable astronomy, space object tracking, and spacecraft communications. Established by the University of Tasmania in 2013, Greenhill was built to replace the Canopus Hill Observatory which dated back to the 1970s. Canopus Hill became swamped by light pollution from the outward growth of suburban Hobart over the decades. By contrast, the Greenhill

[00:07:25] [SPEAKER_02] Observatory is in a dark, radio-quiet location in a dry part of Tasmania, an ideal home for the University to continue its optical astronomy research. It features a 1.3-metre telescope as its astronomy workhorse, plus a 50-centimetre telescope for tracking satellites and space debris. In 2023, the Observatory added a 7.3-metre space communications antenna. That was thanks to a $2 million investment by

[00:07:51] [SPEAKER_02] Acer, the Australian Space Agency. Numerous organisations used the Observatory to communicate with their spacecraft. And the Japanese aerospace exploration agency JAXA is currently using the facility to talk with its Mars Moon Exploration MXX mission, which launched last month and is now heading towards the Red Planet's largest moon Phobos on an historic sample return mission. But one of Greenhill's most significant contributions so far has come from the field of

[00:08:18] [SPEAKER_02] space weather, a variety of phenomena that can damage and destroy spacecraft and disrupt communications and navigation systems, trigger widespread power blackouts and endanger astronauts with increased radiation exposure. You see, the Observatory's 7.3-metre satellite communications antenna detects changes in satellite orbits caused by space weather events, providing data on solar flares or coronal mass ejections erupting from the Sun. The Observatory also undertakes radio science experiments

[00:08:46] [SPEAKER_02] with spacecraft to study how space weather affects Earth's infrastructure. The data helps the Bureau of Meteorology protect assets by accurately predicting coronal mass ejections. Andrew Jackling from the Weather Bureau's Space Weather Forecasting Centre says when material from a coronal mass ejection reaches Earth, it causes a geomagnetic storm, the wobbling of Earth's magnetic field, which heats up the upper

[00:09:09] [SPEAKER_02] atmosphere, causing it to expand, increasing drag on low-Earth orbiting satellites. So if a satellite's not properly boosted during one of these events, the atmospheric drag could literally drop the spacecraft out of orbit. Geomagnetic storms also change the composition of the ionosphere, causing problems for high-frequency communications networks such as those commonly used in the Australian Outback. And they can induce currents in

[00:09:33] [SPEAKER_02] power lines, overloading transformers. And beyond hazardous space weather, there's an even more extreme threat from space that the Greenhill Observatory tracks – potentially dangerous near-Earth asteroids. Greenhill Observatory Director Professor Andrew Cole says asteroid tracking is a key area of research, which the University of Tasmania has been working on using the observatory's capability. Cole says Earth's kind of in the firing line for asteroid impacts,

[00:10:00] [SPEAKER_02] which is not something that people think about very often, because an average person on the ground will probably never be impacted by an asteroid during their lifetime. He says you need to have a presence always monitoring the sky, and develop the right tools and approaches to understand the risks, in order to get the earliest possible advanced warning.

[00:10:18] [SPEAKER_01] There's sort of a continuous range of stones in space, from dust all the way up to house-sized objects and even bigger. Not all of them are known, so that you kind of want to deploy as many observatories as possible to identify them, work out what their orbits are, work out if there's any threat, study their composition and their origin to learn more about them.

[00:10:41] [SPEAKER_02] Can one dedicate a lot of time to this sort of research, tracking, considering the limited budgets available these days?

[00:10:48] [SPEAKER_01] So you don't need a billion dollar, 10 meter telescope or something that's been launched into space in order to do this. A relatively small facility can get it done, and really it's the people power and getting the eyes on the sky that is sort of the limiting factor. So obviously there's a lot to be done and won't be running out of things to observe anytime soon.

[00:11:11] [SPEAKER_02] Tracking neos near Earth objects is important, just ask any dinosaur. Is this something you can piggyback onto other observations the observatory is making, or is this something that really needs to be a stand-alone capability? In other words, you've got to dedicate observing time just to that.

[00:11:26] [SPEAKER_01] There's probably some scope for piggybacking on things and just looking for serendipitous detections when you happen to be looking at something else. But it really kind of has slightly different requirements on the equipment and observing strategies. So you'd probably dedicate specific times in order to do that.

[00:11:47] [SPEAKER_02] I have a special affinity with Green Hill because when I was a somewhat younger person, I was offered the opportunity to do a PhD through the University of Tasmania there.

[00:11:55] [SPEAKER_01] Oh, very cool.

[00:11:56] [SPEAKER_02] For me, Green Hill was something that will always be warm in my heart. Has it got a great camaraderie there among the scientists and researchers?

[00:12:03] [SPEAKER_01] Yeah, I think there's a certain amount of team spirit that kind of builds up when you're doing something and everyone feels like there's a bit of a mission. You know, not just clocking in the hours working for someone else, but there's an actual meaning to what gets done and sort of real world impact potentially.

[00:12:22] [SPEAKER_02] What's the looking like? What are the skies like? I'm talking to you from Sydney, so a lot of light pollution issues to deal with.

[00:12:28] [SPEAKER_01] So we're about 70 k's north of Hobart and it's a pretty rural agricultural area. So the skies are actually reasonably dark. There's a bit of artificial light pollution on the southern horizon, a little bit from the highways. But yeah, it's quite dark and the clear hours are obviously a bit more clear in the summer. In the winter, we tend to get a bit more gray, a bit more rain, but we get some

[00:12:56] [SPEAKER_01] stable weather patterns that can move in and we see things that get image quality that might be maybe comparable to the best sites in Australia. We have really nice, really optimal conditions about a third of the time. And then some other fraction of the time it's observable depending on what project you'd like to get done, depending on whether you want an absolute calibration or sort of relative brightnesses are okay and exactly how stable you need the conditions to be. And then

[00:13:26] [SPEAKER_01] about a third of the time, you might find that it's just no point in even opening up the dome. Is satellite pollution becoming an issue? Yeah, I think in most of our longer exposures, there's always a few satellite trails. If we lock onto one sort of satellite or near-earth object, we often will just notice some other ones kind of drifting through the background.

[00:13:48] [SPEAKER_02] Of course, that's going to get worse as time goes by.

[00:13:51] [SPEAKER_01] Yeah, there's no going back, I think, at this point. There's just every year more and more satellite trails going through the images and can be a real problem in some aspects. It's basically just creating a lot of confusion, a lot of false alarms and obscuring things that might be, you know,

[00:14:10] [SPEAKER_02] a real scientific interest. What are you working on at the moment? What's your project?

[00:14:14] [SPEAKER_01] Is your... So, we've been working on sort of a technical side of basically getting the mirror of the 1.3-meter telescope, sort of polished to a better geometric figure to produce sharper images and gain a lot more sensitivity back relative to how it had been performing. On the scientific side, we've got a couple of PhD students who are using the 50-centimeter telescope

[00:14:38] [SPEAKER_01] to chase up transits of exoplanets and confirm the existence or the non-existence of planetary candidates that have been identified by NASA's test satellite. So, when they detect a planet orbiting another star, those are not confirmed until someone goes back and double checks them all. Sometimes it can be a mistaken identity due to sunspots, star spots, I should say, or flares on a star

[00:15:06] [SPEAKER_01] that can mimic the presence of planets. So, that needs some follow-up. Obviously, the follow-up telescopes are not distributed evenly around the world. So, being pretty far into the Southern Hemisphere gives us a bit of a competitive advantage if we're confirming exoplanets that happen to be in the far Southern sky. So, that's been something that we've been able to do just from here with a couple of small

[00:15:27] [SPEAKER_02] telescopes. It's fantastic. And of course, in the Southern Hemisphere, you get the best view of the

[00:15:31] [SPEAKER_01] galaxy. Yeah, and that's one of the things we also have concentrated on is searching out things that are called gravitational micro-lensing events, where one star happens to pass behind a massive object. It could be a star, it could be a white dwarf, a neutron star, a black hole, anything with a lot of mass. And that mass will deflect the light of the background star, and that can cause it to get brighter and fainter over time. By measuring how that brightness grows and fades, you can learn about

[00:15:59] [SPEAKER_01] the object that's bending the light without actually necessarily seeing that object yourself. You're just using its gravity to tell you about it. You can discover black holes that way. You can discover planets around other stars. The one thing you need is a lot of background stars, and looking towards the centre of the Milky Way is the perfect place for that. That's the Greenhill Observatory's director,

[00:16:19] [SPEAKER_02] Professor Andrew Cole. And this is Space Time. And Time Matter Tech, another brief look at some of the other stories making news and science this week with a science report. A new study warns being born

[00:16:46] [SPEAKER_02] preterm or at low birth weight is linked to poorer cognitive performance in young adulthood. The findings reported in the Journal of the American Medical Association also showed that the effects were more pronounced among those born earlier or lighter. The authors looked at over 190,000 men from Finland who took part in cognitive testing as part of military service when they were 19 to 20 years old. And they found around 10,000 of them were born preterm. Crunching the numbers on preterm births,

[00:17:15] [SPEAKER_02] the authors found men who were born very preterm had the largest cognitive defects compared to those carried full term. Men born moderately preterm had defects but they were smaller. And there was no difference between men born late preterm and those born full term. On birth weight, they found men with extremely low birth weight scored lower on cognitive tests than those born at normal weight. Differences were mainly in tests on numerical and visual abilities and there was no marked

[00:17:42] [SPEAKER_02] differences in speaking ability. The findings suggest that preterm births and low birth weight have lasting effects on cognitive abilities later in life. A new study suggests that weight loss, rather than being on a Mediterranean diet, could be the best way to fight inflammation. Mediterranean diets are widely recommended for a range of health benefits, including reducing inflammation. But the new research reported in the journal Cell Metabolism suggests it may not be

[00:18:09] [SPEAKER_02] the diet itself but the subsequent weight loss that has the anti-inflammatory effect. Over eight weeks, scientists recruited 53 adults, providing half of them with a Mediterranean diet while the rest consumed their normal Western diet. Over the next eight weeks, the participants stayed on their respective diets, but added twice weekly fasting days to trigger weight loss. The authors say the anti-inflammatory effects of the Mediterranean diet relative to those on Western diets were only visible once participants

[00:18:38] [SPEAKER_02] started fasting and subsequently losing weight. That suggests improved weight loss linked to the diet may be the main driver of anti-inflammatory benefits. Scientists are calling for urgent action to protect Australia's native bees from global pollinator decline. A report in the journal Ecology and Evolution points out that Australia is home to an extraordinary diverse native bee population. But there are many major gaps in

[00:19:04] [SPEAKER_02] science's knowledge, which means species could be in decline before scientists have the data to recognise what's happening. The call comes as a new study has found that honey bee hives are actually living immune systems that protect the colony, their offspring and their food supplies from disease. A report in the journal ICME Communications claims the findings underline the need to protect bee habitats and ensure their health.

[00:19:29] [SPEAKER_02] Scientists have created a process using liquid metals powered by sunlight which they say can produce clean hydrogen from both fresh ants seawater. The method described in the journal Nature Communications allows researchers to harvest hydrogen molecules from water while avoiding many of the limits of current hydrogen production methods. The authors say it offers a new avenue for exploration for producing green hydrogen as a sustainable energy source in the future. Residents in the Canadian province of Ontario

[00:19:59] [SPEAKER_02] are now reporting a spate of Bigfoot sightings. Sasquatch has been seen roaming around Chatham, Kent, one of Ontario's least forested and most heavily farmed regions. After an initial sighting, other witnesses reported seeing two of the giant hominids in the same general area around sunrise. One big, the other not so big. Within days more reports were circulating online and were added to the Bigfoot mapping project, a database containing thousands of local Sasquatch sightings going back

[00:20:28] [SPEAKER_02] decades. The reports were then picked up by local media, prompting speculation about a giant undiscovered bipedal ape-like creature roaming the forests. Like the United States, Canada has a long history of cryptid sightings. Centuries before the arrival of Europeans, First Nations people from the North American West Coast were relating oral traditions about large human-like creatures living in the woods which could transition

[00:20:52] [SPEAKER_02] between physical and spiritual worlds. The skeptics Tim Mendham says science does not recognize Sasquatch as a real living animal. He says researchers attribute the phenomenon to a combination of folklore, misidentified wildlife such as bears, hoaxes and cultural storytelling. Mendham points out that despite decades of anecdotal sightings, blurry photos and cast footprints, no verifiable physical body or DNA proof has ever been produced. The thing about Sasquatch or Bigfoot is it's found

[00:21:21] [SPEAKER_00] everywhere. I think every state of America, US, has a Bigfoot sighting. Canada has a lot more too. Obviously it's the same sort of climate just over the border. Ontario, there's supposedly a recent batch of sightings. If you find a forest and that sort of thing, you'll find people sort of seeing strange animals. For example recently of someone saying the birds stopped, the winds died down and it got sort of oddly quiet. And then they had this strong earthy smell, which I presume is like the smell you get when you turn over a compost bin. And then they saw something briefly. And it's always

[00:21:51] [SPEAKER_00] briefly. And again, no one takes photographs of these things. Another one was saying they sort of had a cinnamon smell. There's the thing about Sasquatch, they do supposedly smell it.

[00:21:59] [SPEAKER_02] But every Bigfoot program I've ever seen, and I think I've seen them all, they've always described it as smelling like really bad feet. Yeah, bad feet, yes. Well, they have a very

[00:22:09] [SPEAKER_00] bad personal hygiene regimen. Okay, they don't go for showers. Obviously we need a Bigfoot underarm deodorant or underfoot deodorant, whatever. But yeah, I mean, sort of all these things. So there's a big bunch of sightings. It happens. One place someone sees something and then suddenly everyone does as well. They're in the mood for it. And then it'll die away and come back again. They haven't found the Bigfoot, they haven't got any photographs, they haven't got any bodies, they haven't got any bones. There's no good photography of it. Footprints are often dubious. The plaster of Paris sort of getting an example of a footprint is often sort of as much in the eye

[00:22:38] [SPEAKER_00] of a holder as it is anywhere else. But Sasquatch is everywhere. And we did a study once for our Skeptic magazine. We're finding Sasquatch examples in almost every country in the world, including Australia, including the UK, including obviously Yetis and the Bob and the Muls, Snowmans and that sort of thing. Singapore, you name it, there's a history of a hairy hominid tall wandering around scaring people with glimpses between trees. They can't be long videos of these things. They tend to be, you see it sort of fleeting, which makes it very hard to supply evidence of. It's just anecdotal and

[00:23:07] [SPEAKER_00] people can mistake things for a human. And someone's saying bears, they can stand up on their back legs and they're hairy and they probably smell. Are we hopeful it might be seen to be true? Yeah, probably. But I mean, are we expecting it to be found to be true? No. Which is sad. Because they had a bit of colour, even if it was brown, to our sad, lonely lives. That's the Skeptic's Tim Mendham,

[00:23:27] [SPEAKER_02] and this is Space Time. And that's the show for now. Space Time is available every Monday, Wednesday and Friday through Bytes.com, SoundCloud, YouTube, your favourite podcast download provider,

[00:23:54] [SPEAKER_02] and from Space Time with Stuart Gary.com. Space Time's also broadcast through the National Science Foundation on Science Zone Radio, and on both iHeart Radio and TuneIn Radio. And you can help to support our show by visiting the Space Time store for a range of promotional merchandising goodies. Or by becoming a Space Time patron, which gives you access to triple episode commercial free versions of the show, as well as lots of bonus audio content which doesn't go to air, access to our exclusive Facebook

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