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.
This image of the galaxy REBELS-25 was taken by the Atacama Large Millimeter/submillimeter Array (ALMA), an international facility co-owned by ESO. It shows how cold gas is distributed in the galaxy, and exhibits hints of an elongated bar structure at its centre.
Credit: ALMA (ESO/NAOJ/NRAO)/ L. Rowland et al.
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This image shows the motion of cold gas in the REBELS-25 galaxy as seen with the Atacama Large Millimeter/submillimeter Array (ALMA). Blue colouring indicates movement towards Earth and red indicates movement away from Earth, with a darker shade representing faster movement. In this case, the red-blue divide of the image shows clearly that the object is rotating, making REBELS-25 the most distant rotating disc galaxy ever discovered.
It looks like it's the turn of cosmologists to casually refute creationism by revealing the facts - normally the privilege of biologists and archaeologists who do so with almost every science paper they publish. But of course it would also be difficult for cosmologists to reveal anything about the cosmos that doesn't make those who described it as consisting of a small flat planet with a dome over it, look like anything other than ignorant simpletons who can't be taken seriously.
But of course, they were probably expert at being cattle-herding pastoralists, quite familiar with their few square miles of the Bronze Age Middle East; they just didn't know anything about science or history, so made up tales to fill the gap in their understanding.
Here for example is another cosmology paper showing just how old, immense and awe-inspiring the real Universe is, by reporting the discovery of a stable, rotating disc galaxy, rather like our own Milky Way galaxy, but from just 700 million years after the Big Bang. As such, REBEL-25 is the most distant rotating disc galaxy yet discovered. The discovery was made by an international team of astronomers led by cosmologists from Leiden University, The Netherlands, using data from the European Southern Observatory, Chile.
They have just published their findings in Monthly Notices of the Astronomical Society and announced it in a press release from the European Southern Observatory:
This artist’s impression of a planet-forming disk surrounding a young star shows a swirling "pancake" of hot gas and dust from which planets form. Using the James Webb Space Telescope, researchers obtained detailed images showing the layered, conical structure of disk winds – streams of gas blowing out into space.
I keep returning to the contrast between how the universe is described in Genesis and how it really is as described by science because it illustrates better than almost anything else in the Bible, the naivety and sheer ignorance of the authors. A creator god who wanted us to understand the magnificence of its creation would surely have done a better job of explaining it than to have described it as a small flat planet with a dome over it to keep the water above the sky out, with the sun, moon and stars as lights stuck to the dome.
This description is so far removed from reality that none of it can plausibly be described as allegorical or metaphorical, or even a simplistic description intended to inform simple, uneducated people incapable of understanding anything more complicated. It is simply and laughably wrong; but exactly what parochial pastoralists might think from their limited perspective.
And these same parochial, naïve people came up with the notion of gods to explain the world around them whose working were so mysterious as to look like magic - and magic requires a magician. Where better to locate that magician? Above the dome over the Earth, obviously.
And so religions were built on the best guesses of people who knew no better; people whose best guess was that the Universe consisted of a small flat planet with a dome over it to keep the water above the sky out; people who saw no contradiction in describing the creation of light before the creation of the source of light, or the creation of green plants before the sun!
But how could they, with no technology more complicated than a potter's wheel and the visual acuity of the human eye, possibly know what was really going on as they looked up at the 'little lights stuck to the dome'? How could they possibly have been aware that this Earth is in orbit round the sun, that the sun is but one of half a trillion suns in one of half a trillion galaxies, all existing in a vast, expanding universe in which more than 3000 new stars are being born every second, most of them with an accretion disc from which planets will eventually coalesce?
Had they done so, and had they told us about it, then, and only then, would the notion that a creator god was inspiring them to explain the magnificence of its creation be even a plausible explanation for how they knew that stuff. As it is, all we are left to explain is why they were so ignorant of reality that they needed to invent stories to fill the gaps in their understanding, and of course, the gods they created exactly fitted those gaps, just as todays gods are precisely tailored to fill the gaps in the understanding of ignorant people.
So, how do we know they got things so badly wrong?
An artist’s rendering of what’s called an active galactic nucleus at the center of NGC 4151. The galaxy’s black hole sits at the center, immediately surrounded by an accretion disk shown in blue.
Image credit: JAXA
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XRISM has shown that the accretion disk surrounding a black hole in an active galactic nucleus is warped, confirming earlier hypotheses reflected in this artist’s conception from 2015.
Image credit: International Center for Radio Astronomy Research
I've often remarked on how the stark difference between their laughably childish description of the Universe in the Bible and the reality science is revealing, illustrates the scientific illiteracy of its parochial authors, and so gives the lie to claims that it was written or inspired by a creator god.
They were writing with the knowledge and understanding of Bronze Age pastoralists - which is hardly surprising, since that's exactly what they were. They only knew of the small area around the Canaanite Hills, so nothing that was more than a day or two's walk for them was included, which is why it seemed to them like a small flat planet with a dome over it, and fixed to the dome were the sun, moon and stars; stars being mere small points of light and only those that were visible to the naked eye.
So, just imagine what they would have made of the information if some time traveler from today went back and told them about black holes and the centre of a galaxy 120,000 light years across and containing a billion suns with planets orbiting them! How could they have comprehended the idea of mass bending space-time or something smaller than a grain of sand weighing the same as a million suns?
What would they have made of distances so great that it takes light 120,000 years to travel its length? To them, light was instantaneous; it mattered not whether it came from the sun or the campfire, and the sun was merely a lamp hanging from the dome over the earth. What on Earth was this nonsense about the sun being really big and Earth going round it, things weighing millions of times more than the sun or light taking more time than they thought there had been to travel from one place to another?
They knew nothing of laws of motion and how forces make things move, so they had no concept of gravity. They walked on Earth because they didn't float above it, and they couldn't fly. Only gods and supernatural beings could travel up and down at will. So, what on Earth would mass causing gravity and gravity being an attractive force mean?
Black holes would have been simply beyond their comprehension and outside their experience of the world.
So, of course, they could have included nothing of any of this stuff in the stories they invented to explain things they didn't understand. Had they done so, we might have had some cause to think something must have told them. As it was, they wrote tales that illustrated their scientific illiteracy because they had no option but to do so. They were scientifically illiterate by today's standards.
This Picture of the Week shows a new view of NGC 3603 (left) and NGC 3576 (right), two stunning nebulas imaged with ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA). This infrared image peers through the dust in these nebulas, revealing details hidden in optical images. NGC 3603 and NGC 3576 are 22,000 and 9,000 lightyears away from us, respectively. Inside these extended clouds of dust and gas, new stars are born, gradually changing the shapes of the nebulas via intense radiation and powerful winds of charged particles. Given their proximity, astronomers have the opportunity to study the intense star formation process that is as common in other galaxies but harder to observe due to the vast distances.
The contrast between reality and the Bible's description of it can scarcely be more stark than that between the description of the Universe as a small flat planet with a dome over it as described in Genesis 1: 3-18, and the reality of the universe as it's being revealed in ever greater detail by science.
It's stretching credulity to breaking point to pretend the Bronze Age pastoralists knew full well how large and magnificent the Universe really is, with its countless trillions of galaxies each with half a trillion stars or more, but chose to describe it in some metaphorical way instead, complete with stars that shake loose from the dome and fall to earth during earthquakes. That's not allegorical; it's a mistake from assuming that meteorites burning up in the atmosphere were falling stars - an easy mistake to make if you know neither what stars are nor what meteorites are.
And like the description of meteorites, their description of the rest of it is based on guesses made from a position of ignorance, and an underlying assumption that somewhere up there above it all were magical, superhuman figures creating it all and making it work.
Artist's impression of the interacting galaxies observed in this research
Credit: ALMA (ESO/NAOJ/NRAO), T. Izumi et al
The interacting galaxies observed by the ALMA radio telescope at the Cosmic Dawn. This image shows the distribution of ionized carbon gas, which reflects the overall distribution and motion of interstellar matter. It is clearly visible that the two galaxies are interacting, and are connected by a structure between them. The two crosses in the image indicate the positions of the low-luminosity quasars discovered by the Subaru Telescope.
Creationists find the immensity of the Universe very difficult to force-fit into the creation myth in Genesis which describes it as a small flat planet with a dome over it, so they turn their putative creator god into an Almighty Liar by claiming it just made the Universe look old by placing all the photons to make it look like they started out tens of billions of years ago, when it created everything by magic just 10,000 years ago.
Strangely, they claim they can tell the Almighty Liar lied everywhere in the physical evidence that makes the Universe just look old, because they have a book in which it once told the truth!
Anyway, this is not the only contradictory belief they have to try to ignore, so they'll have no difficulty ignoring the evidence of a chaotic universe which they prefer to believe is perfectly ordered and designed with them in mind.
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The 'Pillars of Creation'.
The 'fine-tuned Universe' argument appeals particularly to those who understand neither physics nor probability and for whom the argument from ignorant incredulity and the false dichotomy fallacies are compelling, partly due to parochial ignorance in assuming that the locally popular god is the only entity capable of creating a universe, and that nothing else, supernatural or otherwise is capable of it.
The most compelling argument against it is the anthropic principle. This means the fact that we are discussing it means we must exist in a universe in which intelligent life is certain.
There is also the subtle blasphemy that most creationists seem not to have thought of in that the argument assumes their putative creator god could only create life within fine-tuned' parameters, so is itself constrained by the same parameters. This denies it's omnipotence and implies the existence of a higher power which set these constraints.
Incidentally, although it's not strictly speaking an argument against the 'fine-tuned' fallacy, note that one of the fundamental forces is the weak nuclear force which governs the rate of radioactive decay. Creationists try to dismiss geochronology based on radiometric dating, claiming, with no evidence whatsoever, that the decay rates used to be much faster, so millions of years can look like 10,000 years or less. This would mean the weak nuclear force was even weaker, by several orders of magnitude.
Probability of dealing a specific bridge hand from a 52-card pack:
\[
P = \frac{1}{\binom{52}{13} \times \binom{39}{13} \times \binom{26}{13} \times \binom{13}{13}}
\]
Which can be simplified to:
\(
P = \frac{1}{\frac{52!}{(13!)^4}}
\) or \(
P \approx 1.86 \times 10^{-29}
\)
Creationists will look at a tiny probability like this and conclude that dealing four bridge hands from a 52-card pack is so improbable as to be impossible, therefore a god must have dealt the cards, and then wave that 'fact' as 'proof' of the locally popular god.
If that were true, as the following dialogue shows, the formation of anything other than hydrogen would not be possible, so stars (which depend on the nuclear fusion of hydrogen to form helium to prevent them collapsing under their own gravity) could not exist, nor could the heavier elements of which living organisms are composed.
Creationists are, probably because they lack the understanding to realise it, and their 'scientists' aren't going to tell them, arguing two mutually contradictory claims simultaneously. They can't both be right, but they can both be wrong.
Of course, given their willingness to try to mislead gullible people into joining their cult, we can never be sure that creationists who try to get away with this fallacy aren't aware they are using a false argument in order to deceive.
The following is a dialogue with ChatGPT4.0, which not only debunks the argument, but shows how it's actually a blasphemy because it argues more strongly against a supreme, omnipotent creator god than for one:
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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What Makes You So Special? From The Big Bang To You
How did you come to be here, now? This books takes you from the Big Bang to the evolution of modern humans and the history of human cultures, showing that science is an adventure of discovery and a source of limitless wonder, giving us richer and more rewarding appreciation of the phenomenal privilege of merely being alive and able to begin to understand it all.
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Ten Reasons To Lose Faith: And Why You Are Better Off Without It
This book explains why faith is a fallacy and serves no useful purpose other than providing an excuse for pretending to know things that are unknown. It also explains how losing faith liberates former sufferers from fear, delusion and the control of others, freeing them to see the world in a different light, to recognise the injustices that religions cause and to accept people for who they are, not which group they happened to be born in. A society based on atheist, Humanist principles would be a less divided, more inclusive, more peaceful society and one more appreciative of the one opportunity that life gives us to enjoy and wonder at the world we live in.
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If there is anything guaranteed to have creationists metaphorically, if not actually, screwing up their eyes, putting their hands over their ears and jumping up and down shouting "'Tisn't! 'Tisn't! 'Tisn't!" its news about the mass extinction 66 million years before 'Creation Week' that exterminated all but the non-avian dinosaurs and the early mammals and about 75% of all other species.
This event reminds them not only that Earth is very much older that their cult requires them to believe but also that Earth is not the 'finely-tuned' haven for life that their belief in a perfect creator requires them to believe. Instead, Earth is very old and subject to unpredictable catastrophes, not the least of which are cosmological events such as meteor strikes and the consequential mass extinctions.
The distorted spiral galaxy at center, the Penguin, and the compact elliptical at left, the Egg, are locked in an active embrace. This near- and mid-infrared image combines data from NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument), and marks the telescope’s second year of science. Webb’s view shows that their interaction is marked by a glow of scattered stars represented in blue. Known jointly as Arp 142, the galaxies made their first pass by one another between 25 and 75 million years ago, causing “fireworks,” or new star formation, in the Penguin. The galaxies are approximately the same mass, which is why one hasn’t consumed the other.
NASA, ESA, CSA, STScI
NASA’s James Webb Space Telescope’s mid-infrared view of interacting galaxies Arp 142 seems to sing in primary colors. The Egg shows up as a tiny, teal-colored oval, because it is made up of old stars and has lost or used up most of its gas and dust. At right, the Penguin’s star-forming regions are represented in pink and purple, and contain smoke-like material known as polycyclic aromatic hydrocarbons.
It takes a special skill to read the description of the universe in the Bible - a single, small flat planet with a dome over it to which the sun, moon and stars are fixed - compared that with what science shows the universe is really like, and conclude that the Bible must have been written by an omniscient, creator god.
And yet grifters like Ken Ham regularly reassure their followers and source of income, that the Bible is their god's inerrant word and god never lies so it must be the science that's wrong. Of course, since it's his source of excuses that he uses to justify fleecing his flock, what he can never afford for them to realise is that we can tell the Bible could not possibly have been written by the god described in it because it differs so widely from reality.
God has always existed, knows all things, and cannot lie.
Why would a god who knew the truth about the Universe uses such a childishly naïve description that it seems to have been written by simple, ignorant people whose entire world consisted of a few square miles of the Middle East, since it contains nothing that wasn't known to them?
Of course, their description was childishly naive because the authors were childishly naïve. It would have been impossible for them to have stood on a Canaanite hill, look up and grasp the true majesty of the Universe - that each tiny point of light could be one of half a trillion stars in a vast galaxy or that other points of light could be one of maybe a trillion other galaxies each with half a trillion stars around which there could be other planets.
At what speed through space would a person standing on a hill in Canaan in 3000 BCE have been travelling?
To calculate the speed through space of a person standing on a hill in Canaan in 3000 BCE, we need to consider three main components of motion:
The rotation of the Earth on its axis.
The Earth's orbital motion around the Sun.
The Sun's orbital motion around the center of the Milky Way galaxy.
We'll break down the calculations for each component and then combine them.
Earth's Rotational Speed
The Earth's rotational speed at the equator can be calculated using the circumference of the Earth and the period of rotation (24 hours).
Radius of the Earth (r): approximately 6,371 km
Circumference at the equator (C): \(2 \pi \times 6371 \, \text{km}\)
Since Canaan is not on the equator, we need to account for its latitude. Let's approximate the latitude of Canaan (modern-day Israel) as about 32°N.
\[\small\begin{flalign*} &\text{Rotational speed at latitude}\\ &= 1670 \, \text{km/h} \times \cos(32°)\end{flalign*} \]
Earth's Orbital Speed Around the Sun
The Earth's average orbital speed around the Sun can be calculated using the circumference of its orbit and the period of revolution (1 year).
Average distance from the Sun (r): approximately 149.6 million km
Sun's Orbital Speed Around the Milky Way
The Sun's orbital speed around the center of the Milky Way galaxy is approximately 220 km/s.
\[\small \begin{flalign*} &\text{Orbital speed}\\ &= 220 \, \text{km/s} \times 3600 \, \text{s/hour} = 792,000 \, \text{km/h}\end{flalign*} \]
Total Speed
To find the total speed, we can combine these three components as vectors. Since the directions are not perfectly aligned, we'll consider a simplified approach by summing the magnitudes approximately, assuming they are roughly perpendicular.
Earth's orbital speed around the Sun:
\[\small 107,000 \, \text{km/h} \]
Sun's orbital speed around the Milky Way:
\[\small 792,000 \, \text{km/h} \]
Since these velocities are mostly perpendicular to each other, we can use the Pythagorean theorem to approximate the total speed:
\[\small\begin{flalign*} &\text{Total speed}\\ &\approx \sqrt{(1417^2 + 107,000^2 + 792,000^2)} \, \text{km/h}\end{flalign*} \]
Let's compute this:
\[\small\begin{flalign*} &\text{Total speed}\\ &\approx \sqrt{(1417^2 + 107,000^2 + 792,000^2)} \, \text{km/h}\end{flalign*} \]
\[\small\begin{flalign*} &\text{Total speed}\\ &\approx \sqrt{(2,007,489 + 11,449,000,000 + 627,264,000,000)} \, \text{km/h}\end{flalign*} \]
\[\small\begin{flalign*} &\text{Total speed}\\ &\approx \sqrt{638,713,007,489} \, \text{km/h}\end{flalign*} \]
\[\small\begin{flalign*} &\text{Total speed}\\ &\approx 799,195 \, \text{km/h}\end{flalign*} \]
Thus, a person standing on a hill in Canaan in 3000 BCE would be travelling through space at approximately 799,195 km/h (496596.75 mph)
They couldn't even conceive of the idea that Earth could be a spinning spheroid with several continents, held in orbit around the sun by gravity or that they could actually be travelling through space at almost 500,000 mph. Even a sizable proportion of Americans find that hard to understand and still believe the sun orbits Earth, which is at the center of the Universe, so what chance did uneducated Bronze Age pastoralists have?
And, as though to rub salt in creationists wounds, although that was far from their reason, NASA has just released stunning photos of a tiny fragment of the night sky that could be hidden behind a grain of rice held up between thumb and fore-finger, in which two galaxies are interacting.
Vivid Portrait of Interacting Galaxies Marks Webb’s Second AnniversaryTwo for two! A duo of interacting galaxies commemorates the second science anniversary of NASA’s James Webb Space Telescope, which takes constant observations, including images and highly detailed data known as spectra. Its operations have led to a “parade” of discoveries by astronomers around the world.
Since President Biden and Vice President Harris unveiled the first image from the James Webb Space Telescope two years ago, Webb has continued to unlock the mysteries of the universe. With remarkable images from the corners of the cosmos, going back nearly to the beginning of time, Webb’s capabilities are shedding new light on our celestial surroundings and inspiring future generations of scientists, astronomers, and explorers.
NASA Administrator Bill Nelson.
In just two years, Webb has transformed our view of the universe, enabling the kind of world-class science that drove NASA to make this mission a reality. Webb is providing insights into longstanding mysteries about the early universe and ushering in a new era of studying distant worlds, while returning images that inspire people around the world and posing exciting new questions to answer. It has never been more possible to explore every facet of the universe.
Mark Clampin
Director of the Astrophysics Division
NASA Headquarters in Washington.
The telescope’s specialization in capturing infrared light — which is beyond what our own eyes can detect — shows these galaxies, collectively known as Arp 142, locked in a slow cosmic dance. Webb’s observations, which combine near- and mid-infrared light from Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument), respectively, clearly show that they are joined by a haze represented in blue that is a mix of stars and gas, a result of their mingling.
Their ongoing interaction was set in motion between 25 and 75 million years ago, when the Penguin (individually cataloged as NGC 2936) and the Egg (NGC 2937) completed their first pass. They will go on to shimmy and sway, completing several additional loops before merging into a single galaxy hundreds of millions of years from now.
Let’s Dance!
Before their first approach, the Penguin held the shape of a spiral. Today, its galactic center gleams like an eye, its unwound arms now shaping a beak, head, backbone, and fanned-out tail.
Like all spiral galaxies, the Penguin is still very rich in gas and dust. The galaxies’ “dance” gravitationally pulled on the Penguin’s thinner areas of gas and dust, causing them to crash in waves and form stars. Look for those areas in two places: what looks like a fish in its “beak” and the “feathers” in its “tail.”
Surrounding these newer stars is smoke-like material that includes carbon-containing molecules, known as polycyclic aromatic hydrocarbons, which Webb is exceptional at detecting. Dust, seen as fainter, deeper orange arcs also swoops from its beak to tail feathers.
In contrast, the Egg’s compact shape remains largely unchanged. As an elliptical galaxy, it is filled with aging stars, and has a lot less gas and dust that can be pulled away to form new stars. If both were spiral galaxies, each would end the first “twist” with new star formation and twirling curls, known as tidal tails.
Another reason for the Egg’s undisturbed appearance: These galaxies have approximately the same mass or heft, which is why the smaller-looking elliptical wasn’t consumed or distorted by the Penguin.
It is estimated that the Penguin and the Egg are about 100,000 light-years apart — quite close in astronomical terms. For context, the Milky Way galaxy and our nearest neighbor, the Andromeda Galaxy, are about 2.5 million light-years apart. They too will interact, but not for about 4 billion years.
Now, look to the top right to spot a galaxy that is not at this party. This edge-on galaxy, cataloged PGC 1237172, is 100 million light-years closer to Earth. It’s also quite young, teeming with new, blue stars.
Want one more party trick? Switch to Webb’s mid-infrared-only image to see PGC 1237172 practically disappear. Mid-infrared light largely captures cooler, older stars and an incredible amount of dust. Since the galaxy’s stellar population is so young, it “vanishes” in mid-infrared light.
Also take a moment to scan the background. Webb’s image is overflowing with distant galaxies. Some take spiral and oval shapes, like those threaded throughout the Penguin’s “tail feathers,” while others scattered throughout are shapeless dots. This is a testament to the sensitivity and resolution of the telescope’s infrared instruments. (Compare Webb’s view to the 2018 observation that combines infrared light from NASA’s retired Spitzer Space Telescope and near-infrared and visible light from NASA’s Hubble Space Telescope.) Even though these observations only took a few hours, Webb revealed far more distant, redder, and dustier galaxies than previous telescopes – one more reason to expect Webb to continue to expand our understanding of everything in the universe.
Want more? Take a tour to the image, “fly through” it in a visualization, and compare Webb’s image to the Hubble Space Telescope’s.
Arp 142 lies 326 million light-years from Earth in the constellation Hydra.
Credit: NASA, ESA, CSA, STScI, Danielle Kirshenblat (STScI)
Video: Arp 142 Visualization
Credit: NASA, ESA, CSA, Ralf Crawford (STScI), Joseph DePasquale (STScI), Christian Nieves (STScI), Joseph Olmsted (STScI), Alyssa Pagan (STScI), Frank Summers (STScI), Greg Bacon (STScI)
Hover over the dividing line then click to move and compare the two images
Hubble Space Telescope
Webb Space Telescope
A selection of images from the James Webb Space Telescope in 2024
Oh! Silly me! That last one isn't from the James Webb Space Telescope! It's the way the people who wrote the Bible thought the Universe looked like! spot the difference!
It defies belief that there are adults, mostly in the USA, who believe that description in the Bible far surpasses for accuracy and reliability anything that science can reveal, and that this 'amazing accuracy' is proof that it was written by an inerrant god who created it all.
You might expect the fact that the Bible's description is so hilariously naïve would be taken as evidence that the description is proof of exactly the opposite: that the Bible could not have been written by an omniscient god who created the Universe it so inaccurately describes, but there is something about religion that seems to prevent intellectual honesty and the humility to allow evidence to inform opinion. Religion seems to produce the delusion that opinion informs the evidence and if they conflict, then opinion trumps evidence.
The same people also claim to worship a god who told them that vanity is a mortal sin, and a terrible fate awaits those who transgress.
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