May 17, 2026
Galactic Black Hole Eruptions, Snowball Earth Theories, and the Impact of SkyMapper
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RSS Feed RSS Feed SpaceTime Series 29 Episode 59 *Black hole flare explodes in the heart of our galaxy Astronomers have observed a dramatic mid-infrared flare erupting from Sagittarius A*- the supermassive black hole at the centre of our galaxy. *A new explanation for Snowball Earth Scientists have developed a new explanation for one of our planet’s great climate puzzles: how a snowball Earth event known as the Sturtian glaciation could have lasted so long. *The legacy of Australia’s Sky Mapper – so far The fourth and most recent data release by the Sky Mapper southern survey has covered more than half the sky, generating some four hundred thousand images, showing 700 million objects and achieving 15 billion detections. *The Science Report Obesity trends growing faster in low- and middle-income countries compared to high-income nations. The Gulf Stream continuing to weaken, threatening global climates. Palaeontologists discover a new type of plant-eating dinosaur in Southeast Asia. Skeptics guide to pseudo-archaeology. Our Guests This Week: Siding Spring Observatory director Dr. Christian Wolf Alex Mumford local Isle of Rum resident who organized the Dark Skies application And our regular guests: Alex Zaharov-Reutt from techadvice.life Tim Mendham from Australian Skeptics 🌏 Get Our Exclusive NordVPN deal here ➼ www.bitesz.com/nordvpn . The discounts and bonuses are incredible! And it’s risk-free with Nord’s 30-day money-back guarantee! ✌
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The Astronomy, Space, Technology & Science News Podcast.
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This is Spacetime Series twenty nine, Episode fifty nine, for
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broadcast on the eighteenth of May twenty twenty six. Coming
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up on Spacetime, A black hole flare explodes in the
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heart of our galaxy. Trying to explain one of the
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mysteries of snowball Earth and the legacy of Australia's Skymappers survey.
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So far, All that and more coming up on space Time.
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Welcome to space Time with Stuart Gary.
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Astronomers have observed a dramatic mid in for red flair
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erupting from Sagittarius, a star, supermassive black hole at the
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center of our galaxy. The discovery, reported on the pre
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press physics website archive dot org, follows twenty years of
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searching for just such an event. Sagittarius a star is
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located some twenty seven thousand light years away at the
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very heart of the galaxy, and it has some four
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point three million times the mass of our Sun. This
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new detection was made by the WEB Space telescope, which
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is exquisitely sensitive to admit infrared events. Web's observations show
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that the blast lasted some forty minutes, and its implications
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could fundamentally transform sciences understanding of black hole behavior and
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the violent magnetic environments just outside their event horizons. The
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event horizon is the point of no return around the
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black hole, beyond which matter falls forever into the black
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hole's singularity, a point of infinite density and zero volume,
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where science is understanding of the laws of physics, space
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and time break down. While Sagittarius a star has been
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seen flaring before, recorded in radio waves, near infrared and
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X ray frequencies, the mid infrared window has remained stubbornly
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dark until now, and so this new observation finally completes
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a long sort after supermassive black hole's multi wavelength portrait,
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astronomers think the flare was triggered by something called magnetic reconnection.
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This involves intensely tangled magnetic food lines near the black
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hole suddenly realigning, snapping, and then reconnecting, unleashing a massive
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pulse of energy in the process, and that energy accelerated
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electrons to relativistic speeds, which then emitted synotron radiation as
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they whipped around the reconfigured magnetic fields. This new observation
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has allowed astronomers to see the event unfold in real time,
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revealing the unmistakable spectral fingerprint of synotron radiation cooling as
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the high energy electrons bled away energy through radiation. These
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new observations will allow astronomers to better directly probe and
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measure the black hole's magnetic field strength near the event
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horizon with unprecedented detail, to develop a better understanding of
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how super massive black olds devour matter, ignite sudden outbursts,
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and exert their gravitational and magnetic dominance over entire galaxies.
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This is space time still to come, a new explanation
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for some of the unsolved riddles about snowball Earth, and
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we look at the legacy so far of Australia's SkyMapper project.
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All that and more still to come on space time.
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Scientists have developed a new explanation for one of Earth's
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great climatic puzzles, how a snowball Earth event known as
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the Sturdy and Glaciation could have lasted as long as
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it did. The research publishing the Proceedings in the National
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Academy of Sciences suggests that, rather than a single fifty
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seven million year long unbroken snowball Earth state, Sturdy Glaciation
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may have seen the planet oscillate between fully ice covered
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conditions and more ice free states. As the name suggests,
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snowball Earth events occur when our planet is almost completely
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covered in snow and ice. The exact reasons for this
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are still under active debate, although plate tectomics and changes
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in Earth's orbit and axial tilt are thought to have
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played at least a part in these dramatic climatic change events.
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Scientists generally agree on two major snowball Earth periods. These
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were the Sturdy Glaciation, which went from around seven hundred
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and seventeen to six hundred and sixty million years ago,
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and the Marino Glaciation from around six hundred and fifty
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to six hundred and thirty five million years ago. Some
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scientists suggest there may will have been a third earlier
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glaciation event, known as the mcganny Glaciation, which occurred at
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around two point two billion years ago. However, the exact
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length and intensity of all these events remains uncertain, and
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the fifty six million YU duration of the Sturdy Glaciation
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during Earth's Crogian period is especially problematic as it challenges
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some climate models. The studies lead author Charlotte Minsky from
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Harvard University says this was a time which predates the
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age of the dinosaurs in most complex lifeforms. Minsky and
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colleagues used a coupled model of the ancient climate and
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the global carbon cycle to show that the Earth may
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not have been locked in a single unbroken snowboll earth
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state or period when the entire planet was frozen over. Instead,
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they proposed a planet likely oscillated between fully ice covered
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snowball conditions and more ice free hothouse intervals throughout the
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sturdy In period. The author's simulation suggest that intense weathering
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of basalt in the Franklent large igneous province, a vast
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volcanic region located in northern Canada, leave to have erupted
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just before the onset of the Sturdy glaciation, may have
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drawn down atmospheric cab dioxide, a greenhouse gam and it
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removed enough of it from the atmosphere to trigger modible
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global glaciations. As volcanoes and other processes slowly rebuilt atmospheric
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carb dioxide, the climate warmed again and the ice retreated,
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and large areas of fresh basalt were again exposed to
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the atmosphere. The renewed breakdown from weathering then pulled cob
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dioxide back down, pushing the climate into another snowball phase.
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The authors argued that this repeating cycle of calm dioxide
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driven freezing and thawing could naturally sustain glacial interglacial swings
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over tens of millions of years. The mechanisms revealed by
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this study resolved several long standing paradoxes, most noticeably the
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previously inexplicable length of the Sturtian compared with physical climate models.
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The study also matches observed sedimentary patterns from that time
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period and it explains how atmospheric oxygen levels could have
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remained stable despite extreme climate up evils. The study seeings
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that repeated returns to warmer, ice free conditions may have
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helped prevent a complete collapse of atmospheric oxygen, and Minski
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says this could explain how aerobic life persisted through such
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an extreme period. This is space time still to come.
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We look back at the legacy so far of Australia's
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sky Mapper Southern Survey, and later in the science report,
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paleontologists discover fossils of a new type of plant eating
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dinosaur in Thailand all that and more still to come
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on space time. It was almost exactly ten years ago
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that the Australian National University sky Mapper telescope released an
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initial eighteen terabytes of observations of the Southern Skies. Was
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the first of more than two petabytes of raw and
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calibrated information that has helped change forever sciences understanding of
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the cosmos and our play in it. By the time
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of its fourth and most recent data release, SkyMapper Southern
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Survey covered more than half the sky, generating some four
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hundred thousand images showing seven hundred million objects and achieving
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fifteen billion detections. SkyMapper is a wide field survey telescope
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located at the Siting Spring Observatory in far western New
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South Wales. Observatory is director Christian Wolf, says skymappers unprecedented
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images and measurements are creating the first comprehensive digital survey
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of the entire Southern Sky. He says the end result
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will be a massively detailed record of more than a
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billion stars and galaxies, all to a sensitivity of a
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million times fainter than what the human eye can see.
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Yes, we've been looking for quasars, especially e quasars at
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high redshift in the early Universe quite a while. Now.
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Sky Mapper is a bit late to that game, because
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a lot of quasars in the Early Universe have been
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found by the Sloan Digital Sky Survey or the Northern
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Sky and SkyMapper is in the first survey that really
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goes to similar depths studying the Southern skies. But really
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what we want to do is push the envelope and
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really get good demographics of the fastest growing and most
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massive black holes in the universe. What we also can
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do is quasars are supposed to be a really really
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large distances, and especially when we believe they are in
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the early Universe, then they're not supposed to move at all,
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as opposed to the foreground stars of our own Milky Way.
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And so we were able to read out our candidate list,
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which are we're trying to look for these high retive quasars,
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and then because their colors are similar to cool stars
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in our own galaxies, our lists of possible high chif
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us are polluted with vast amounts of Milky Way stars
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that we're not really interested in. And when we want
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to know what a particular object is. We have to
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point a spectrograph at it, at a somewhat bigger telescope,
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and then we have to check them off one by one.
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So what is this exactly? If this is a start out,
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take the spectrum, a stuff, this one over here is that,
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let's take a spectrum, another star, and so on, and
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you can't afford to go through all of them because
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there would be millions of candidates. So really, Gaya has
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helped us to weed out a lot of this contamination
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by a milky ways four ground stars. It doesn't completely
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remove that we still find stars among our candidates, but
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at least it's now being realistic to find these very
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rare and very fast growing, very bright kays as. Our
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work right here with the skymert the telescope focused on
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getting the big guys, the monsters, and we believe that
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they have been largely overlooked. In fact, anytime someone has
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discovered the now brightest or now fastest growing black holes,
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they've been saying, wait a minute, we've had this on
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our candidate lists forever. We thought this was a star.
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We were pretty sure this was a star. We didn't
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you look at it in detail? Because it was so
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unlikely to actually be a quasus. When you look at
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very faint objects, you get a number of quadars among
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the stars. But as you go to brighter and brighter ones,
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quasars become rapidly raarer, up to the point where you think, well,
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we haven't seen anyone brighter than this one, so you
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know they are probably pretty rare. So everything you then
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see at that brightness you think must be a star anyway,
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So we have this kind of biased few that the
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brightest ones are most likely stars, so we don't go
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after them because we don't enjoy taking spectra of a
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thousand stars only to learn that there wasn't a single
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black hole or quasa among them. That we probably don't
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even get the time telescopes avoid for that, just because
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it's such an such an unlikely to be successful undertaking.
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And this is why we have missed the monsters. There
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are monsters out there, and but that's what we are
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setting out to correct now. So by combining Gaya that
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we thow a lot of the candidates from the candid
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list with Taypa. That can take still so many spectra
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of objects, most of which are not going to equas us,
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we can actually afford to attempt to get the complete
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demographics of bright praisers in the early universe and therefore
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map out the growth of black holes with time in
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the early epochs.
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With these sky data online and being available for everyone
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to see, that's got to be a tremendous boost for
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astronomy generally. I think it's what developing something like two
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petabytes of data starting the southern sky thirty six times
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six hundred thousand images something like that.
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Yes, that's the right order of magnitude indeed, And fortunately
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the sky Mapper project was intended to start up ten
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years earlier, but the first prototype of the Skyper system,
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that was actually at Mount Stromlow just outside of Canberra,
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was burned down in the early bushfires of January two
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thousand and three. Then it took a while to build
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a brand new sky Mapper, which then was of course
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put at siding Spring Observatory, which also almost precisely on
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the tenth anniversary of the Stromlow bushfires. The siding Spring
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bushfires happened and Skymper was about ready to start its
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survey and was inundated in ash and it took four
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months of meaning of the optic mechanics and everything to
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get it back to where we wanted it, and we
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actually did lose some kit in the process, some little kit,
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but anyway, so in some ways we are fortunate because
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the capacity of computers and discs and so on has
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improved a great deal over time, so now we can
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actually do it for a reasonable cost. We offer our
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data online over the Internet. Everyone can access it, scientists, teachers,
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the interested public who just wants to have a look.
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Guymapper has several color filters, six of them that cover
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the the color range from the near ultra violet, which
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the human eye just about cannot see anymore, through the
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visual that the I sees very well too, equipments in
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the near infrared that again the eye just about can't
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see anymore. And stars show usually typical color patterns, but
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the exact pattern depends on how many absorption lines are
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in the spectrum, and most stars in Milky Way have
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quite a lot of these absorption lines and have really
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areas where the absorption lines are heavily affecting the colors.
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And when you get something like a nearly perfect rainbow,
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then you know, oh we have a metal poor star.
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That's what we call it a star with few heavy elements,
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a star with few absorption lines. And so we're selecting
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these stars baits on their color. And then again we
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need to go to a bigger telescope and take some
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more refined measurements, measure the spectrum indeed, and see what
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we've got. How metal poor is it, how chemically pristine.
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On the one hand, we really look for thousands of
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these metal poor stars which are from the first generation
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of stars formed in our Milky Way galaxy around about
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thirteen billion years ago.
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These will be population two stars.
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Yeah, these are population two stars. And these are actually
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extreme population two stars, not just average population.
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The ones that actually were formed from those population threes.
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That's right, that's right. I mean, the term population two
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stars still covers a couple billion years of time in
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