A spiral galaxy with a disc made up of several swirling arms. Patchy blue clouds of gas are speckled over the disc, where stars are forming and lighting up the gas around them. The core of the galaxy is large and shines brightly gold, while the spiral arms are a paler and faint reddish colour. Neighbouring galaxies - from small, elongated spots to larger swirling spirals - can be seen across the black background.
Take a grain of rice and hold it between your thumb and forefinger at arm’s length while looking up at the night sky. The patch of sky hidden behind that tiny grain of rice probably contains thousands of galaxies—each with around half a trillion stars. Some of these stars are ancient, nearing the end of their tens-of-millions-of-years lifespans; others are just beginning to form from clouds of gas and debris left behind by older stars that exploded as supernovae.
What lies behind that grain of rice is a tiny fragment of a dynamic, evolving, ever-changing, and expanding universe. A universe of which our ancient prophets were completely unaware as they crafted imaginative descriptions of its origins—descriptions written just a few thousand years ago that portrayed it as a small, unchanging cosmos, with a flat Earth at the centre covered by a dome.
But let’s not be too hard on them. As they stood in their Canaanite pastures, the Earth must indeed have looked flat and small, and the sky would have seemed like the roof of a great tent, adorned with tiny lights and with the sun and moon suspended from it. To them, the Earth appeared fixed and immobile while the dome overhead turned slowly, or perhaps invisible spirits moved the lights across the heavens each night. They didn’t know where the sun went after sunset and imagined the moon might hide in a deep valley during the day.
This image, taken with ESO’s Very Large Telescope (VLT), shows a spiral disc around the young star HD 135344B.
ESO/F. Maio et al.
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This image, captured with ESO’s Very Large Telescope (VLT), shows a spiral disc around the young star HD 135344B. The image, which was released in 2016, was obtained with the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument.
It takes a special form of self-deluding immunity to facts and reason for creationists to cling to the absurd belief that the Bible’s description of a small universe formed *ex nihilo* in a few days — by nothing more than a few magic words spoken in a language no one was alive to understand — could possibly reflect reality.
Meanwhile, science continues to produce evidence for a very old, immense universe that is constantly changing and evolving, where new stars and planetary systems are being observed as they form. Many of these systems lie so far away that the light from them has taken billions of years to reach us — in stark contrast to the few thousand years allowed by the Biblical narrative.
As I’ve previously explained on this blog, modern astronomy and the wealth of evidence it provides shows that the Biblical account is not merely inaccurate — it is irredeemably wrong. It can’t even be salvaged as metaphor or allegory. It is exactly as wrong as one would expect from people who believed the Earth was a small, flat disc with a dome over it, and that life was created out of soil, fully formed, just a few thousand years ago.
Today, we have yet more evidence that utterly refutes the Bible’s creation myth — and this time, it doesn’t come from events billions of years ago, but from a mere 440 light-years away. That means the light we’re seeing now set off on its journey in 1585 — the same year Sir Walter Raleigh attempted to found the ill-fated Roanoke Colony in North America, and the Anglo-Spanish War broke out.
Astronomers at the European Southern Observatory (ESO), using the Very Large Telescope (VLT), have observed a giant planet forming within the accretion disk of a young star — exactly as the modern theory of planetary formation predicts. In other words, the universe is still forming and evolving, in complete contradiction to the static, one-time-only creation described in Genesis.
HOPS-315, a baby star where astronomers have observed evidence for the earliest stages of planet formation.
This image shows jets of silicon monoxide (SiO) blowing away from the baby star HOPS-315. The image was obtained with the with the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner.
One of the more dishonest tactics employed by creationist grifter Ken Ham is his infamous question: "Were you there?" As though the only valid form of evidence is eye-witness testimony. The implication is clear—if you didn’t personally observe a species evolving, then you have no grounds to claim that evolution occurred. And by extension, Ham suggests that his own creationist claims are equally valid and deserve the same consideration as scientific explanations, despite the fact that he wasn't there either.
Of course, this deliberately ignores the many well-documented instances of observed evolution and the overwhelming fossil evidence showing gradual transitions over time.
He applies the same fallacious reasoning to cosmology, dismissing scientific accounts of Earth’s and the solar system’s origins on the grounds that no one was there to witness them. As though this somehow makes the biblical Bronze Age myth—a magical spontaneous assembly in response to divine incantation—equally plausible.
In a typically cynical move, Ham teaches children to parrot this question as a way to shut down scientific discussion. Rather than encouraging curiosity with the far more constructive question, "How do you know that?" — a gateway to learning about observation, extrapolation, and logical reasoning — he arms them with a slogan designed to obstruct inquiry and preserve ignorance, while making them feel smugly superior to the scientists having exposed the 'flaw' in their reasoning.
But now, thanks to cutting-edge astronomical research, science has delivered something akin to “being there” at the birth of a planet.
An international team of researchers, using the ALMA telescope (operated in part by the European Southern Observatory) and the James Webb Space Telescope, have observed what appears to be the formation of an Earth-like planet in the accretion disk of a young star. This is direct evidence supporting the scientific model of planetary formation — the very process that explains the origins of Earth and the solar system.
Predictably, this discovery will require some creative misrepresentation from creationists to dismiss it. No doubt we’ll hear claims that it’s not really the same process that formed Earth, or that it doesn’t disprove Genesis — because defending ancient mythology apparently requires ignoring any modern evidence that makes it look absurdly naive.
Credit: ESA/Hubble & NASA, M. Monelli
Acknowledgement: M. H. Özsaraç
A cluster of stars in space. It’s bright in the centre, where the stars are densely packed together in the cluster’s core, and grows dimmer and more diffuse out to the edges, as the stars give way to the dark background of space. A few orange stars are spread across the cluster, but most are pale, bluish-white points of light. Three large stars with cross-shaped spikes around them lie between us and the cluster
Credit: ESA/Hubble & NASA, M. Monelli
Acknowledgement: M. H. Özsaraç
The ESA/Hubble photograph of the week offers a glimpse into a vast and ancient universe—one that starkly contrasts with the primitive cosmology described in the Bible. The image captures a globular cluster in the Large Magellanic Cloud, a small satellite galaxy of the Milky Way, located some 160,000 light-years from Earth. What we’re seeing, then, is a snapshot of this cluster as it was 160,000 years ago—long before the writers of the Bible imagined their god creating a small, flat Earth with a dome over it, to which the sun, moon, and stars were affixed, somewhere in the vicinity of the Canaanite hills.
At the time, the light we’re now seeing began its journey across space, early humans in Africa were evolving the skills and traits that would eventually allow them to leave the continent and colonise new territories. According to [a recent study](https://www.science.org/doi/10.1126/science.adi1768), there had been earlier migration attempts northward, but these failed to establish lasting populations for reasons still debated by researchers.
What this photograph shows us—quite literally—is a universe that predates the biblical account of creation by well over 150,000 years, and a cosmos that bears no resemblance to the geocentric, dome-covered world described in Genesis. While we can’t know exactly how our early ancestors viewed the night sky, their understanding was likely not very different from that of the later Bronze Age storytellers who wrote the biblical texts. Both were constrained by limited technology, and neither had any inkling of galaxies, light-years, or cosmic timescales.
The day long anticipated by those who understand both science and theology may finally have arrived. Scientists have detected—with a 99.7% probability—the unmistakable signs of life on the distant exoplanet K2-18b.
Although this degree of certainty doesn't yet satisfy the rigorous standards of science, which typically require a confidence level of greater than 99.99994%, researchers anticipate surpassing that threshold within the next 16 to 24 hours (as of this article's publication).
The theological implications of this discovery are profound. If confirmed, as now seems highly likely, it would indicate that Earth is not unique as a cradle of life, directly challenging biblical narratives which position Earth exclusively as the divinely chosen habitat for humanity. The Bible remains thoroughly anthropocentric and geocentric, offering no indication that life or divine creation occurred elsewhere in the comparatively small and flat universe it describes.
For creationists, this finding significantly undermines their long-standing argument—summarised by the simplistic slogan, "You can't get life from non-life"—which claims life could only arise through divine intervention. The presence of life on K2-18b demonstrates that life can indeed emerge naturally under the right conditions, suggesting such events may be far more common across the universe than creationist arguments would allow. Indeed, with potentially trillions of planets sharing Earth-like conditions, life may not only be possible but prevalent.
This discovery also challenges creationist claims about Earth's position in the so-called 'Goldilocks zone'. Creationists frequently argue that Earth's precise placement around the Sun proves divine intent. However, the existence of life-supporting conditions on K2-18b shows that such habitable zones are not rare, singular phenomena but commonplace, existing around countless other stars across the cosmos.
The discovery, by astronomers, led by the University of Cambridge, using data from the James Webb Space Telescope (JWST), is the subject of an open access paper in The Astrophysical Journal Letters and is described in a Cambridge University press release by Sarah Collins:
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Analysing the cosmic microwave background in high definition has enabled researchers to confirm a simple model of the universe, ruling out many competing alternatives.
Creationists today face a distinct challenge compared to their predecessors from one or two centuries ago. They must continually devise ways to ignore or dismiss the relentless flow of scientific evidence disproving their beliefs, while simultaneously rationalizing the complete lack of evidence supporting claims of a young Earth, special creation through supernatural means, or the existence of a creator capable of producing a universe from nothing.
Individuals with a normal degree of intellectual honesty, when confronted with overwhelming evidence against their beliefs and a lack of supportive evidence, would naturally see this as grounds for doubt and reassessment. Creationists, however, appear undeterred, convinced that their personal beliefs override scientific evidence without the necessity for evidential justification.
Compounding their difficulties, scientists recently announced a significant advancement: they have mapped the cosmic microwave background radiation—the residual echo of the Big Bang—in unprecedented detail. Utilizing data from the Atacama Cosmology Telescope (ACT) collaboration, this new research reveals conditions in the universe as they existed only 380,000 years after the Big Bang, roughly 13.8 billion years ago.
On the scale of a human lifetime, this is the equivalent of a photograph of a now middle-aged person, taken one hour after they were born, and, in a confirmation of the principle of Occam's Razor, the simplest model is conformed as the correct model.
A point I never tire of making because it contrasts so vividly what the authors of the Bible thought the Universe was like and what science is showing us it is really like, is the ludicrously naive description of a small, flat planet with a dome over it, with the moon, sun and starts attached to the dome.
Don't take my word for it. Open your Bible and read the first few pages:
And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so. And God called the firmament Heaven. And the evening and the morning were the second day. And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so. And God called the dry land Earth; and the gathering together of the waters called he Seas: and God saw that it was good. (Genesis 1.6-10)
And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.(Genesis 1.16-18)
How the Bible's authors saw the Universe.
Now compare that with the view of just a small fragment of the universe that the European Space Agency's space telescope, Euclid, has revealed today:
It's one thing for creationists to dismiss evidence of life on Earth hundreds of millions, or even a billion or two years before the so-called 'Creation Week' by misrepresenting dating methods and making the absurd claim that the Universe is so finely tuned for life that altering just one parameter slightly would render life impossible, while also claiming that radioactive decay rates were much higher during 'Creation Week', making radiometric dating inaccurate by orders of magnitude.
However, it's quite another to argue that the speed of light was much slower in the past, which would mean that objects appearing to be billions of light-years away are actually much younger than we observe them today.
But a ludicrous and false argument which is not easy to spot by the scientifically illiterate fools that creationists target, was seen by creationists as any reason not to try to get away with it on a different audience.
So, if they don't simply ignore this discovery, it will be interesting to see which lies the creation cult uses to dismiss it. It is the discovery of a galaxy, designated JADES-GS-z14-0) from just 300 million years post Big Bang, discovered by the James Webb Space Telescope (JWST).
This discovery, along with the fact that it is chemically complex, challenges the standard model for galaxy formation as well as the synthesis of 'heavy' elements (i.e., heavier that hydrogen, helium and lithium) because JADES-GS-z14-0 shows evidence of substantial quantities of oxygen. The standard model explains that heavier elements are formed in the end-stages of the life of a sun when its hydrogen supply has all been used up and it collapses under its own gravity. This high gravity forces helium nuclei together to form the heavier elements. When the sun finally explodes in a supernova these elements are thrown into space supplying the next generation os stars with these higher elements.
Q. How do we know the Bible could not possibly have been written by the god described in it?
A. The Bible describes the god it purports to have been inspired by as all-knowing, yet there is a great deal the Bible gets wrong, and even more that is left out. Clearly, whoever wrote it was ignorant of a great deal and almost all of what little they thought they knew they got hopelessly wrong.
For example, the opening few verses of Genesis make it plain that the authors thought the Universe consisted of a small, flat planet, on which they and everything they knew about lived. This planet had a dome over it from which the sun and moon were hung and in which the stars were embedded. The Bible even described how these stars could be shaken loose during earthquakes whereupon they would fall down to Earth.
This description of the universe bears no resemblance to the real universe and is clearly a description of what someone standing on a hill in Canaan thought his universe consisted of. It could scarcely be further from the truth.
There is simply no reason for an omniscient god to have got it so wrong; it's not even of the category of a 'lie to children', like the planetary model of an atom, designed to foster understanding of some of the properties of atoms without the complication of having to understand some quantum physics. The small, flat planet with a dome over it at the centre of the universe provides nothing by way of a useful model with which we can explain observed phenomena.
It is wrong, plainly and simply, and as such has served throughout the centuries to confuse and mislead, to endarken rather than to enlighten us.
No matter how much you insist that words meant something different in those days, or the description is a poetic allegory or a metaphor the meaning of which is beyond us, the early verses of the Bible clearly and unambiguously describe a universe consisting of a small flat planet with a dome over it with the sun, moon and stars stuck to the underside of the dome.
This, of course, is a childlike description of what the authors saw as they looked up into the sky and saw what looked like a dome, and Earth was more or less flat, give or take a few low hills, so that is what, in their child-like naivety, they described:
How the Bible's authors saw the Universe.
And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so. And God called the firmament Heaven. And the evening and the morning were the second day. And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so. And God called the dry land Earth; and the gathering together of the waters called he Seas: and God saw that it was good.
Genesis 1.6-10
And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years: And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so. And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.
Genesis 1.14-18
Now, as we learn more about the Universe as we develop increasingly sophisticated scientific instruments for examining it, we discover just how childishly naïve the Bible's authors were and so show to anyone interested in truth that the Bible could not possibly have been written or inspired by the creator god described in it, unless that god wanted to mislead us so that it would take humanity another three thousand years or more to discover its lies - and what would have been the point of that?
Mind you, the same creator god could have told us about germs, atoms or electricity or how to make a steam engine or a motor car, but either chose not to or didn't know about those things, because the people who invented it didn't know about those things either. What 'science' there is in the Bible is no better than the primitive understanding of Bronze Age pastoralists.
The Middle Eastern Bronze Age pastoralists who made up the Hebrew creation myths that later found themselves bound up in a book declared to be the inerrant word of a god, were probably aware of the planet Mars.
Certainly, the Sumerians, Egyptians, Greeks and Romans were and even named it after one of their gods - Nergal, Her Dashur, Ares and Mars, respectively. Because of its red colour, it was associated with blood and, by extension, war and violence.
But of course, the authors of Genesis thought it was stuck to the dome over their small flat planet, so they assumed it was made during 'Creation Week' and so had as little knowledge of its history as they had of their own planet - i.e., none at all. Had they realised Mars had water forming oceans, lakes and rivers 3 billion years earlier (they didn't even have a word for a number so large), they could have made up a slightly more plausible creation myth, at least as far as a time-scale is concerned.
But of course, as a small red light stuck to the dome, they had no more idea than fly how it got there, why it looked red or what it could tell them about planetary orbits. Although they don't even give it a mentions, presumably they must have had some inkling that it was different to the other little lights as it 'wandered' over the undersurface of the dome, like some of the other little lights - magical mystery, probably involving angels or other magic spirits, no doubt.
But what was it exactly that changed Mars from being a wet planet, with an atmosphere and probably suitable for life to evolve on, to being a cold, dry, unsuitable, even hostile place, where life as we know it could not exist, certainly on its surface or as advanced multicellular organisms.
I know I'm always writing about things that happened before creationism's mythical 'Creation Week', but the problem is, almost everything that happened happened then. 99.9975% of Earth's history happened then, for example, and far more of the Universe's, since the Universe is some 3-4 times as old as Earth and an awful lot happened between the Big Bang and the formation of the sun and its planetary system.
And so, true to form, this is about the time 466 million years ago, when, according to the findings of three researchers from Monash University, Melbourne, Victoria, Australia, led by Professor Andrew G. Thomkins, Earth had a ring system, somewhat like those of Jupiter and Saturn. They believe the ring was composed of the debris of a large asteroid that passed close enough to Earth to be broken up by gravitational tidal forces.
The result was a sudden plunge into an ice age and a period of intense bombardment with meteorites lasting millions of years and producing an otherwise difficult to explain pattern of impact craters.
Creationist have been fooled by their cult to believe that the Universe is 'fine-tuned' for life and that this 'fine-tuning' is proof of their particular god and its particular holy book.
This is a blatant false dichotomy fallacy; even if it could be proved to be true by showing that the various (and usually ill-defined) parameters could have other values it does not follow that a randomly designated god is responsible for 'tuning' them.
It's also a blasphemy, if creationists did but realise it, because it assumes their supposedly omnipotent god is itself constrained by the fundamental laws of chemistry and physics and could only work to create life within very narrow constraints - which implies a higher power to set that constraint.
How many black holes are there in the known Universe?
Estimating the exact number of black holes in the known Universe is challenging, but astronomers have made some educated guesses based on our current understanding.
Stellar-Mass Black Holes
Stellar-mass black holes, which form from the collapse of massive stars, are the most common type. Based on the number of stars in the Universe and the fraction of those stars that are massive enough to form black holes, it is estimated that there are around 100 million to 1 billion stellar-mass black holes in the Milky Way galaxy alone. Given that the Milky Way is just one of about 2 trillion galaxies in the observable Universe, the number of stellar-mass black holes across the Universe could be in the range of \({10^{18}}\) to \({10^{19}}\) (a billion trillion to 10 billion trillion).
Supermassive Black Holes
Supermassive black holes, which exist at the centers of galaxies, are much rarer. Almost every galaxy with a significant size is thought to have a supermassive black hole at its center. This suggests there could be around 2 trillion supermassive black holes in the observable Universe, one for each galaxy.
Primordial Black Holes
There is also the theoretical possibility of primordial black holes, which might have formed in the early Universe. These could range in mass from very small to large and could number in the vast quantities, though their existence has not been confirmed.
Total Estimate
In total, combining these different types, the number of black holes in the observable Universe could be as high as \({10^{19}}\) or more. This estimate is still very rough, as it depends on many factors, including the formation rates of black holes, the life cycle of stars, and the evolution of galaxies.
But it is nonsensical for another reason: life is not the most abundant manifestation of the laws of physics in the Universe; that honour goes more deservedly to black holes, of which there are estimated \(\small {10^{19}}\) in the observable Universe - far more than there are living organisms - and black holes don't require special conditions in which to exist, other than a Universe with enough mass.
And black holes, far from showing that the Universe is a place designed to be friendly to life (which only the most parochial and naive simpletons could imagine, given that most of it above a few thousand feet of the surface of Earth is hostile to most forms of life and only a fraction of the surface is hospitable without special adaption or complex technology), are about the most destructive thing in the Universe, reducing everything that comes within their event horizon to energy which can only escape in the form of Hawking radiation.
So, if anything, the Universe appears to be 'fine-tuned' for self-destruction and the eventual extermination of life. Not exactly what the creation cults want their dupes to believe.
This theory has the advantage of a possible explanation for the appearance of design just as living organisms have, in the form of the Theory of Evolution. Black holes are believed to contain the quantum conditions for universes to spontaneously arise, so, if there were a mechanism for passing information through a black hole from the parent universe to a descendant one, natural selection should mean universes get better at making black holes.
How black holes swallow up entire suns, compete with any orbiting planets is the subject of a recent paper in Astrophysical Journal Letters which show computer generated simulations of the event. One notable observation if the 'spaghettification' effect where, from the point of view of a distant observer, an object falling into a black hole becomes drawn out into a thin string, like toothpaste out of a tube. This is caused by the dilation of space and time due to the increasing gravity as the black hole is approached and is an effect of General Relativity.
One of the authors of this paper, Professor Daniel Price of Monash University, Australia, has published an article about the team's findings in The Conversation. His article is reprinted here under a Creative Commons license, reformatted for stylistic consistency:
Watch a star get destroyed by a supermassive black hole in the first simulation of its kind
Giant black holes in the centres of galaxies like our own Milky Way are known to occasionally munch on nearby stars.
This leads to a dramatic and complex process as the star plunging towards the supermassive black hole is spaghettified and torn to shreds. The resulting fireworks are known as a tidal disruption event.
In a new study published today in the Astrophysical Journal Letters, we have produced the most detailed simulations to date of how this process evolves over the span of a year.
A black hole tearing apart a sun
American astronomer Jack G. Hills and British astronomer Martin Rees first theorised about tidal disruption events in the 1970s and 80s. Rees’s theory predicted that half of the debris from the star would remain bound to the black hole, colliding with itself to form a hot, luminous swirl of matter known as an accretion disc. The disc would be so hot, it should radiate a copious amount of X-rays.
An artist’s impression of a moderately warm star – not at all what a black hole with a hot accretion disc would be like.
But to everyone’s surprise, most of the more than 100 candidate tidal disruption events discovered to date have been found to glow mainly at visible wavelengths, not X-rays. The observed temperatures in the debris are a mere 10,000 degrees Celsius. That’s like the surface of a moderately warm star, not the millions of degrees expected from hot gas around a supermassive black hole.
Even weirder is the inferred size of the glowing material around the black hole: several times larger than our Solar System and expanding rapidly away from the black hole at a few percent of the speed of light.
Given that even a million-solar-mass black hole is just a bit bigger than our Sun, the huge size of the glowing ball of material inferred from observations was a total surprise.
While astrophysicists have speculated the black hole must be somehow smothered by material during the disruption to explain the lack of X-ray emissions, to date nobody had been able to show how this actually occurs. This is where our simulations come in.
A slurp and a burp
Black holes are messy eaters – not unlike a five-year-old with a bowl of spaghetti. A star starts out as a compact body but gets spaghettified: stretched to a long, thin strand by the extreme tides of the black hole.
As half of the matter from the now-shredded star gets slurped towards the black hole, only 1% of it is actually swallowed. The rest ends up being blown away from the black hole in a sort of cosmic “burp”.
Simulating tidal disruption events with a computer is hard. Newton’s laws of gravity don’t work near a supermassive black hole, so one has to include all the weird and wonderful effects from Einstein’s general theory of relativity.
But hard work is what PhD students are for. Our recent graduate, David Liptai, developed a new do-it-Einstein’s-way simulation method which enabled the team to experiment by throwing unsuspecting stars in the general direction of the nearest black hole. You can even do it yourself.
Spaghettification in action, a close up of the half of the star that returns to the black hole.
The resultant simulations, seen in the videos here, are the first to show tidal disruption events all the way from the slurp to the burp.
They follow the spaghettification of the star through to when the debris falls back on the black hole, then a close approach that turns the stream into something like a wriggling garden hose. The simulation lasts for more than a year after the initial plunge.
Zoomed-out view, showing the debris from a star that mostly doesn’t go down the black hole and instead gets blown away in an expanding outflow.
What did we discover?
To our great surprise, we found that the 1% of material that does drop to the black hole generates so much heat, it powers an extremely powerful and nearly spherical outflow. (A bit like that time you ate too much curry, and for much the same reason.)
When observed like they would be by our telescopes, the simulations explain a lot. Turns out previous researchers were right about the smothering. It looks like this:
The same spaghettification as seen in the other movies, but as would be seen with an optical telescope [if we had a good-enough one]. It looks like a boiling bubble. We’ve called it the “Eddington envelope”.
The new simulations reveal why tidal disruption events really do look like a solar-system-sized star expanding at a few percent of the speed of light, powered by a black hole inside. In fact, one could even call it a “black hole sun”.
Daniel Price, Professor of Astrophysics, Monash University
Published by The Conversation. Open access. (CC BY 4.0)
For the technically-minded, more detail is given in the paper in Astrophysical Journal Letters:
Any creationists wishing to refute this paper will need to refute the details given here:
Abstract
Stars falling too close to massive black holes in the centres of galaxies can be torn apart by the strong tidal forces. Simulating the subsequent feeding of the black hole with disrupted material has proved challenging because of the range of timescales involved. Here we report a set of simulations that capture the relativistic disruption of the star, followed by one year of evolution of the returning debris stream. These reveal the formation of an expanding asymmetric bubble of material extending to hundreds of astronomical units — an outflowing Eddington envelope with an optically thick inner region. Such outflows have been hypothesised as the reprocessing layer needed to explain optical/UV emission in tidal disruption events, but never produced self-consistently in a simulation. Our model broadly matches the observed light curves with low temperatures, faint luminosities, and line widths of \(\small {10,000}–{20,000}\;\text{km/s}\).
1 Introduction
In the classical picture of tidal disruption events (TDEs), the debris from the tidal disruption of a star on a parabolic orbit by a supermassive black hole (SMBH) rapidly circularises to form an accretion disc via relativistic apsidal precession (Rees, 1988). The predicted mass return rate of debris (Phinney, 1989) is \(\small \propto t^{5/3}\) and the light curve is assumed to be powered by accretion and to follow the same decay.
This picture alone does not predict several properties of observed TDEs, mainly related to their puzzling optical emission (van Velzen et al., 2011; van Velzen, 2018; van Velzen et al., 2021). These properties include: i) low peak bolometric luminosities (Chornock et al., 2014) of \(\small \sim {10^{44}}\;\text{ergs/s}\) \(\small \sim\) 1 per cent of the value expected from radiatively efficient accretion (Svirski et al., 2017); ii) low temperatures, more consistent with the photosphere of a B-type star than with that of an accretion disc at a few tens of gravitational radii (\(\small R_{g}\equiv GM_{\mathrm{BH}}/c^{2}\)) (Gezari et al., 2012; Miller, 2015), and consequently large emission radii, \(\small \sim {10}-{100}\) au for a \(\small 10^{6}M_{\odot}\) black hole (Guillochon et al., 2014.1; Metzger & Stone, 2016); and iii) spectral line widths implying gas velocities of \(\small \sim {10^4}\;\text{km/s}\), much lower than expected from an accretion disc (Arcavi et al., 2014.2; Leloudas et al., 2019; Nicholl et al., 2019.1).
As a consequence, numerous authors have proposed alternative mechanisms for powering the TDE lightcurve, via either shocks from tidal stream collisions during disc formation (Lodato, 2012.1; Piran et al., 2015.1; Svirski et al., 2017; Ryu et al., 2023; Huang et al., 2023.1), or the reprocessing of photons through large scale optically thick layers, referred to as Eddington envelopes (Loeb & Ulmer, 1997), super-Eddington outflows (Strubbe & Quataert, 2009), quasi-static or cooling TDE envelopes (Roth et al., 2016.1; Coughlin & Begelman, 2014.3; Metzger, 2022) or mass-loaded outflows (Jiang et al., 2016.2; Metzger & Stone, 2016). Recent spectro-polarimetric observations suggest reprocessing in an outflowing, quasi-spherical envelope (Patra et al., 2022.1).
The wider problem is that few calculations exist that follow the debris from disruption to fallback for a parabolic orbit with the correct mass ratio. The challenge is to evolve a main-sequence star on a parabolic orbit around a SMBH from disruption and to follow the subsequent accretion of material (Metzger & Stone, 2016). The dynamic range involved when a \(\small 1M_{\odot}\) star on a parabolic orbit is tidally disrupted by a \(\small {10^6}_{\odot}\) SMBH is greater than four orders of magnitude: the tidal disruption radius is 50 times the gravitational radius, where general relativistic effects are important, while the apoapsis of even the most bound material is another factor of 200 further away. This challenge led previous studies to consider a variety of simplifications (Stone et al., 2019.2): i) reducing the mass ratio between the star and the black hole by considering intermediate mass black holes (Ramirez-Ruiz & Rosswog, 2009.1; Guillochon et al., 2014.1); ii) using a Newtonian gravitational potential (Evans & Kochanek, 1989.1; Rosswog et al., 2008; Lodato et al., 2009.2; Guillochon et al., 2009.3; Golightly et al., 2019.3), pseudo-Newtonian (Hayasaki et al., 2013; Bonnerot et al., 2016.3) or post-Newtonian approximations (Ayal et al., 2000; Hayasaki et al., 2016.4); iii) simulating only the first passage of the star (Evans & Kochanek, 1989.1; Laguna et al., 1993; Khokhlov et al., 1993.1; Frolov et al., 1994; Diener et al., 1997.1; Kobayashi et al., 2004; Guillochon et al., 2009.3; Guillochon & Ramirez-Ruiz, 2013.1; Tejeda et al., 2017.1; Gafton & Rosswog, 2019.4; Goicovic et al., 2019.5); and iv) assuming stars initially on bound, highly eccentric orbits instead of parabolic orbits (Sadowski et al., 2016.5; Hayasaki et al., 2013, 2016.4; Bonnerot et al., 2016.3; Liptai et al., 2019.6; Hu et al., 2024).
These studies have, nevertheless, provided useful insights into the details of the tidal disruption process. In particular, it has been shown that the distribution of orbital energies of the debris following the initial disruption is roughly consistent with \(\small dM/dE\) = const, consistent with the analytic prediction of a \(\small \propto t^{5/3}\) mass fallback rate, although the details can depend on many factors such as stellar spin, stellar composition, penetration factor and black hole spin (Lodato et al., 2009.2; Kesden, 2012.2; Guillochon & Ramirez-Ruiz, 2013.1; Golightly et al., 2019.3; Sacchi & Lodato, 2019.7). The importance of general relativistic effects in circularising debris has also been demonstrated. The self-intersection of the debris stream, which efficiently dissipates large amounts of orbital energy, is made possible by relativistic apsidal precession (Hayasaki et al., 2016.4; Bonnerot et al., 2016.3; Liptai et al., 2019.6; Calderón et al., 2024.1). But until recently debris circularisation has only been shown for stars on bound orbits, with correspondingly small apoapsis distances and often deep penetration factors (we define the penetration factor as \(\small \beta\equiv R_{\mathrm{t}}/R_{\mathrm{p}}\), where \(\small R_{\mathrm{t}}=R_{*}(M_{\mathrm{BH}}/M_{*})^{1/3}\) is the tidal radius and \(\small R_{\mathrm{p}}\) is the pericenter distance).
Recent works have shown that circularisation and initiation of accretion is possible in the parabolic case, by a combination of energy dissipation in the ‘nozzle shock’ that occurs on second pericenter passage (Steinberg & Stone 2024.2; but see Bonnerot & Lu 2022.2 and Appendix E for convergence studies of the nozzle shock) and/or relativistic precession leading to stream collisions (Andalman et al., 2022.3).
In this paper, we present a set of simulations that self-consistently evolve a one solar mass polytropic star on a parabolic orbit around a \(\small {10^6}\) solar mass black hole from the star’s disruption to circularization of the returning debris and then accretion. We follow the debris evolution for one year post-disruption, enabling us to approximately compute synthetic light curves which appear to match the key features of observations.
Figure 1:One year in the life of a tidal disruption event. We show shapshots of column density in the simulation of a \(\small 1M_{\odot}\) star on a parabolic orbit with \(\small \beta = {1}\), disrupted by a \(\small {10^6} M_{\odot}\) black hole, using \(\small 4\times 10^{6}\) SPH particles in the Schwarzschild metric. Main panel shows the large scale outflows after 365 days projected in the \(\small {x}-{y}\) plane with log scale. Inset panels show the stream evolution on small scales (\(\small{100}\times {100}\) au), showing snapshots of column density projected in the \(\small {x}-{y}\) plane on a linear scale from \(\small {0}\;\text{to}\; {1500}\;{g/cm^2}\) (colours are allowed to saturate). Animated versions of this figure are available in the online article. Data and scripts used to create the figure are available on Zenodo:https://doi.org/10.5281/zenodo.11438154 (catalog doi:10.5281/zenodo.11438154)
The Universe is far from the ideal environment for life to thrive in - known life only exists as an encrustation on or near the surface of a single planet. Instead, it is a violent and unstable chaos of competing forces with an estimated \(\small {10^{19}}\) supper-dense, massive black holes, which far exceeds the number of life forms in the known Universe, drawing to inevitable annihilation any body that strays too close.
It requires parochial ignorance of the first order to imagine that the entire Universe is designed for life. It is far easier to make a case for it being designed for black holes, although that, as with the 'designed for life' case, case would require a priori evidence of the existence of a creative entity in the form of an explanation of its origins and definitive evidence of it ever being recorded as creating anything. And by recorded, I don't mean written in the mythology of Bronze Age pastoralists who thought the Universe was a small flat place with a dome over it and containing nothing that was unknown within a day or two's walk of the Canaanite Hills where they grazed their goats, and later decreed to be literal history by people with a vested interest in people believing the myths.
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