This is a very personal document. And it doesn't suggest it gets things right. If you want the 'right' account, you have to go elsewhere; you have to learn about science, and go to the scientists. I just wanted to see if I, as a complete 'lay person', with no scientific training or background, could prepare an account of my reading of a scientific world that made any sense whatsoever. It is a set of ideas, lifted from others, that allows me to organise a timeline that makes sense to me. I have been reading this stuff for years, a lifetime, as I go about doing other 'things', and, whilst doing that, it all makes complete sense. Then I drop it and, when I come back, I have to re-read & it has to be re-organised & re-understood. And new events and new exposures call it all into question, and I have start again. Such is the way of the on-looker.
Many of the ideas here have been lifted from a great writer on science and astrophysics, Mario Livio. He is my favourite at the moment because he describes difficult and complex ideas in astrophysics in a way that can be understood by people like me. He is talking to the 'common man', as the British would say in the C19th.
Many of the ideas here are lifted from his Brilliant Blunders: From Darwin to Einstein - Colossal mistakes by great scientists that changed our understanding of life and the universe (2014). And there is an underlying analytic theme running through this timeline that uses these 'blunders' (as he does) as a tool to move from one temporal landscape to the next. I have also incorporated ideas he offers us in his Is God a Mathematician? (2010) and his Why? What makes us curious? (2017).
If I have stuffed up his ideas in doing that, I have to apologise. But I feel it has been very useful for me to reorganise my understanding in this manner. It gives me a running commentary from Copernicus to the present that makes sense to me. That is all I was after.
Leonardo da Vinci https://www.huffpost.com/entry/the-da-vinci-astronomy_b_4065100
Modern astronomy begins with Copernicus. (Nicholaus Copernicus 1473-1543 Royal Prussia (Poland)).
He was an economist, an observer & a mathematician. He was also a clergyman, as many of the thinkers were in the Renaissance. If you weren’t in the chapel, you were likely to be in the fields, reaping what you sow, & paying your tithe to the clergy, to allow them to do their thinking in the chapel.
Prior to Copernicus, the church told us God created the earth in 7 days, therefore the earth was stationary & the sun, the moon & the stars were there at God’s behest, & in different spheres that rotated around the earth, providing mankind with the beauty & glory of life on earth.
That’s how it felt to everyone; it was a good story.
Copernicus - National Geographic https://www.nationalgeographic.com/history/world-history-magazine/articl...
But Copernicus, with his mathematics, proved this to be not so.
By observing the movement of the sun, the moon & the stars, he found there were serious problems with this idea. For example, the stars didn’t move in a ‘designed’ fashion, evenly around the earth, as one would expect if they were in a sphere, but rather seemed to be doing crazy things.
Copernicus used his mathematics to explain what they were doing. Their so-called movement could be properly explained if you assumed that the earth was not stationary but was rotating around the sun.
He was not the first to have the idea of a moving earth. They say Greek philosophers like Pythagoras & Arabic scholars had similar theories. But he was the first to prove it. His mathematics allowed him to prove it, in a way that the theologists studying the Bible only dreamed of doing.
Being a 'clergy', though, he had problems with this idea, as it directly contradicted the story told in the Bible. He tried to give it to the Pope to help the Church on a new (scientific) road of discovery, but it was not to be, & was only able to publish his wonderful theories just before he died, for fear of persecution by a Church unwilling to accept new ideas.
After him comes Galileo; a true astronomer, polymath, inventor. (Galileo Galilei 1564-1642 Pisa)
Galileo took on Copernicus’s model & turned it into a map for observing the solar system, using his new telescopes, as evidence, and his maths to to define what he could see. See Livio's wonderful snapshot:
Galileo, like Copernicus, invented major tools for science. His work gave rise later to great scientists like William Hershel, English astronomer. With his polymath, they say, he was the first to come up with the idea that everything falls, due to gravity, at the same rate regardless of its mass (or weight), which is fundamental to Newton's major breakthrough model and fundamental to everything that Einstein later came up with.
Galileo, they say, based on a guess, simply dropped different objects from the leaning tower of Pisa, and measured the time taken to hit the ground.
He was a great observer, viewing the moon, the planets, the moons of the planets, etc. He gave us the Milky Way.
He was rewarded for his wonderful work in understanding the solar system & the Milky Way by imprisonment (our 'detention') & ‘torture' at the hands of the Catholic Church’s Inquisition.
A mad raving Christian & a brilliant story teller on a range of subjects, & a wonderful observer, mathematician & logician in the Holy Roman Empire, Johannes Kepler (1571-1630 ), took the works of Copernicus & Gallileo & set out to use their theories to assist him in looking up into God's heavens. But when he tried to do that, he found that the narratives they had given him didn't add up. Like Gallileo's 'circles' of the planets orbiting the sun didn't properly describe what he could see. The planets seemed to be doing crazy things. Kepler used his ability to reason & his mathematics to describe what they were doing.
Galileo's ideas for developing modern astrophysics received a huge boost with Newton. (Isaac Newton, 1643-1727 England)
He doesn’t just want to know what’s happening, but wants to explain it. If the earth is in motion, how could that be?
Newton's model is fundamental to the astrophysics that follows, right up to the modern day. Scientists still use his model & tell us much of what he said still is true & apparent, it just doesn’t tell the full story.
His picture of the world in planetary orbit around the sun & its place in the universe was astoundingly accurate & ground breaking & hard to believe, that, like Einstein, work like his in a few short years could change everything we know about the universe. He brought on modern science.
He basically allowed us to understand ‘gravity’.
Newton took Galileo’s ball dropping at the same speed, regardless of its mass and applied it to what was happening to the earth in space.
His idea was very basic:
Something 'mass' =m at 'inertia' (absolute rest) will remain so unless impacted by a 'force' (F).
That is, to move from from 'inertia' to 'speed' requires energy. How much energy? F=ma. Where a=the amount of acceleration you need to get it to required speed.
So it seemed to Newton apparent that something in motion in space will continue at its constant speed unless impacted by a force. Force is therefore equal & opposite.
Newton also gave us the tools for understanding the basics of movement through space. Not any easy concept. If you want to calculate the speed of something, you have to have something to measure it against. Stationary in relation to what? If your car speedometer says 16 kph, this is meaningless unless we first know "Moving at 16 kph in relation to what?"
For the earth, Newton solved the problem using the concept of an imaginary ‘ether'. This was widely accepted by those trying to find ways of calculating things as a useful construct. It allowed them to get on with the job.
It set up the notion of 'relative frames of reference'.
Before this work, everybody (after Copernicus) thought the earth was moving around the sun because of some sort of hidden power (God) & its rotating on its axis by some sort of hidden power (God) but, following Newton, in modern terms, we think of all those assumptions as an 'illusion'.
For Newton, it’s just sitting there (in space) and continually falling (changing its frames of reference) because of gravity.
Its ‘traverse' & its ‘rotation’ is just the nature of its fall in relation to everything else in the universe. Newton's work on the true nature of that ‘illusion', provides the basis for all the ‘true’ calculations (begun by Copernicus), like the spin of the earth (day), its degrees of axis in relation to the sun (season), ‘full rotation around the sun (year), etc. This 'illusion' is the beginnings of Einstein’s 'special relativity' and then 'general relativity'. 'Relativity' meaning movement (or motion) of everything in relation to everything else.
Newton also started to wonder what would happen if you could dig a hole through the middle of the earth, & dropped Galileo's ball down it, what would happen? Would it keep going? at what rate? would it slow down? what would be the rate of deceleration? would it stop at the middle? Interesting questions for the scientist using F=ma to understand the movement of the ball, through space.
But he surmised that because of volcanoes & molten lava spewing from underground that it’s pretty hot down there, which led him to start to ‘believe’ the earth had started as a molten ball in space a bit like the sun & had eventually cooled down. So if he started digging his hole, he wouldn't get very far. And then he wondered how much it had cooled & how long it would take to get through the crust that had cooled.
Newton's law of cooling https://www.sciencedirect.com/science/article/pii/S0017931020334803
We have to remember he is having these ideas at a time when the Christians were concluding, from reading Genesis literally, that God created the earth under 6,000 years ago. People in fundamentalist religion like Morrison still make that blunder today & they have no knowledge how stupid that is, in the face of scientific evidence.
Newton's law of cooling: calcs https://christinejoyocampo.wordpress.com/2018/08/15/application-of-newto...
There was lots of argument at the time about how much time it would take for the earth to cool down from that early state to its present state. Newton suggested that if the planet started as a red hot iron ball 40 million feet in diameter it wouldn’t cool more than a few degrees in 50,000 years. So the Christians' 6,000 years seemed pretty stupid to the scientists.
At about the same time as Newton (1676), the Danish scientist/philosopher Ole Roemer (1644-1710) viewing the eclipses of Jupiter by one of its moons, Io, noticed that it took longer(shorter) for him to get that information as the earth moves away(towards) Jupiter in the orbit of the earth, and said that the only reason for that lengthening(shortening) 'could be' that light is taking a longer(shorter) time to get to him. This means that the speed of light is finite (and therefore measurable). Up until that time there was a tendency for observers to assume that the speed of light was too fast to measure or was in fact infinite.
Roemer suggested that if you knew the distance of the earth's orbit, and the difference between the longest & the shortest time taken, you would have a reasonably accurate calculation of the speed of light.
On that suggestion, the Dutch scientist Christiaan Huygen (1629-1695), a great mathematician, did the calculations and found the speed of light to be about 131,000 miles per second, an amazingly accurate calculation, given the time of the calculation. In fact, the difference was mainly due to errors in Roemer’s estimate for the maximum time delay (the correct value is 16.7, not 22 minutes), and also to an imprecise knowledge of the Earth’s orbital diameter, at the time.
In 1676, astronomer Edmond Halley (London, 1656-1742) (also known for his discoveries & formulations in geophysics, mathematics, meterology, & physics) sailed to St Helena, a remote volcanic British colonial island in the South Atlantic to observe & catalogue 341 stars in the Southern Hemisphere & discover a cluster in Centaurus. He made the first observation of the planetary transit of Mercury & proposed that a similar observation of the transit of Venus could be used (using parallaxism) to calculate the size of the Solar System. He worked with Giovanni Cassini in Paris to observe a comet & determine its trajectory. He became editor & publisher of Newton's Philosophiae Naturalis Principica Mathematica (1687).
In 1705 Halley wrote a work that brought together 4 separate observations of comets 1456, 1531, 1607, 1682, proposing that these were so similar that they could only be the same comet engaged in a (Newton's) orbit, and thereby predicted it would return 1758. When it turned up, as he said it would, after his death, it became known as Halley's comet.
In 1771, using the method proposed by Halley (parallaxis, parallax, i.e. apparent visual angular differences) and using the data obtained from different locations on earth of the eclypse of the sun by Venus 1761 and 1769, the French astronomer Jérôme Lalande (1732-1807) calculated the distance between the sun and the earth to be 153 million kilometres or 95 million miles.
This methodology, parallaxism, often consigned as designed by Halley & proven by Lalande, (what we now call the phenomenon of a trigonometric parallax), became fundamental to astronomy & remains so, to the current day. For example, now that we have Lalande's calculation (AU) we can use his methodology (the parallax against 'fixed' stars) to calculate with incredible accuracy the distance (d) to a star:
William Herschel's (German/English 1738-1832) observations, 1781:
When Herschel discovered from his observations the planet Uranus, he thought that its blue-green tint meant that he had discovered a 'planetary nebula', a gas cloud, thereby initiating the term & the search for gas giants, nebulae. (Observers still call them planetary nebulae today, although no planets are involved. For example in about 5 billion years our star will have given off its outer layers and it will become a short living shell of diverse gas, a nebula.) The first real nebula, Dumbbell Nebula M27, was discovered by Charles Messier in 1764.
Caroline Herschel's (Germany 1750-1848) observations, 1781:
Scottish geologist Charles Lyell (1797-1875), took part in a new school of geology that arose from Newton's consideration of how long the earth has been around. Newton's conclusion that there seems no way to calculate how long it would take for the earth to cool down was being discussed by geologists. Lyell he said it barely matters. Volcanism, sedimentation, erosion, the ice caps, needs so much time, we can sort of assume them to be timeless, just assume they have been there for the eternity of the earth, a bit like infinity. Just get on with it.
These new ideas, and the discussion between the geologists & the astrophysicists, the ideas of 'uniformitarianism' and 'gradualism', leads to, & gives some strength to, Charles Darwin in his quest to understand the beginning of life on the planet.
Charles Darwin (1809-1892, England) took on looking at life on one of Newton's planets (i.e. over the enormous (then unknown) period of time). He took Newton's new idea of 'how long it would take' & applied it to 'time of life' on the planet earth. He started looking at the near & not the far, analysing what we have on earth, & following on Newton’s argument, how we know them to be true or false, & without him doing that, the whole concept of astrophysics would still be narratives, stories, like Plato & Aristotle told, and, like your book, have ‘followers’ or ’schools’ of thought, but could not be taken on to be "proven to be true or thrown into the dustbin of history as false” which is what separates the scientists from the story tellers, and the Christians and their nonsense of “6,000 years”.
Darwin took Lyell's ideas of 'uniformitarianism' and 'gradualism' and used them to generate an account of the current species existing today that came from the beginning of life on the planet, to the present, by analysing ‘change’:
Darwin’s 'change theory' was based on 4 theories:
(1) ‘evolution' (“life forms are continually changing”);
(2) 'common descent', (everything comes from some “one prime ordeal form”);
(3) ‘gradualism' (because “time is so immense” we may not see it happening, but because of (1) it is happening, so we need to generate ways of seeing gradual change), and
4) ‘speciation' (all of life is broken up into 'species' which are (because of common descent) the same life forms but (because of evolution & gradualism) very different at the same time.
All these changes, he said, are driven by 'natural selection'.
It is amazing, if you look at the scientific account of the universe today, how important these concepts are to describing the beginnings of the universe, & the current state of the universe.
Modern scientists like Mario Livio tell us there were problems with 'natural selection' because it suggested the species getting stronger over generations as natural selection takes out the weak & leaves us only with those strong enough to survive.
This is a problem as an idea because, as there is no plan in the mind of God, it cannot be 'teleological'. That is to say, because Darwin is taking out the concept of God planning everything, if going forward something fails, & you want the outcome to be the species getting stronger, you would have to have at your disposal, exactly at that time, exactly what you need to make it stronger. If there is no God, natural selection doesn’t & can’t do that, which means that 'imperfections' are the fingerprint of Darwin's 'natural selection'.
Solving this problem long after Darwin has gone becomes the basis of science; a long drawn out scientific enquiry, giving us things like chemical components, one component changing into another, medical research, & becomes the basis for looking into the universe to see what 'differences' ('imperfections' if you like) the universe is made up of, how long they have been around, what changes into what, the full she-bang of modern astrophysics.
Livio also asks if Darwin’s theory has the problem of being 'tautological', meaning "if only the strongest survive, their survival means they were the strongest", which means it is non scientific and can’t be proven, just an assumption we know to be true.
Asking this question allows us to look into Darwin’s mind.
The history Darwin’s scientific enquiry & interactions with other philosophers & scientists suggest that Darwin is aware of this problem, mainly because of arguments with Jenkins' raising serious concerns. Darwin tries to get around this problem by introducing ‘variables'. That is to say, variables from one generation to the next create ‘expected' survival but because of 'competition for limited resources' some survive others don’t, the result is therefore "survival of the fittest”.
By these ‘variables', & combining them with common descent, Darwin is unknowingly giving us the basis for the discovery of DNA down the track, the combinations & the variables of life on the planet.
Let’s look at how the argument leading to that goes: Darwin’s concept of ‘variables' that are 'heritable' (able to be passed on), that he used to get around his problem, was actually a blunder, says Livio, because it saw it as 'blending', so Darwin's blunder was not in the passing down of heredity, which he got right, & forms the basis of modern science, but in not realising the full implications of his theory.
The blending heredity:
If you combine A with B first generation
second generation XA BY
third generation IXA2 3BY4
4th generation 51AB26 7ABY48 ETC
AFTER 12 GENERATIONS THE ‘A' BIT
Like if A is a black cat & after 12 generations you get a black cat, blending is not happening cos the black cat part can only be one part in 2048 cats. It’s gunna be very ‘unblack’. As Darwin's theory was all about variables, blending removes his variables so it can’t be correct. Ya can’t have it both ways.
The failure of Darwin to solve his ‘variables’ problem using a ‘blending’ of ’types’ or ‘characteristics’ from one generation to the next was basically solved by Gregor Johann Mendel, meteorologist, mathematician, biologist, Augustinian friar & abbot of St. Thomas's Abbey (Moravia, 1822-1884) who planted plants in his garden & expected results & checked the actual results against what he expected.
So while Darwin looked at life over millions of years, he had little to check his ideas against.
He used some information he collected to high success, like he proved he was correct about 'species' by visiting the Galapagos islands and proving that finches could have offspring by mating with those on the nearby island but those on the 1st island couldn't mate with those on the last island. They had over the process of sub-species developed a completely new species.
Mendel on the other hand could check his assumptions immediately in his garden. This gave him what we would call a ‘particulate' or an ‘atomistic' theory of heredity. And unlike Darwin he could check that theory. His ‘particulars' (or the Greek philosophers' ‘atoms’), which he called ‘factors’, were preserved during development & passed on absolutely unchanged to the next generation. (These ‘factors' we now call 'genes').
Mendel needed those ‘factors’ to explain what was actually happening in his garden. The 'heredity' he comes up with works a bit like:
First generation AA combines with BB
second generation AA BB AB (‘possibilities’)
each of these ‘possibilities' can combine with CC possibilities to become
AA BB CC AB AC BC
and so on.
Not blending but a tree of life.
If AA is a black cat there is still the possibility of a black cat in each generation.
They hand on Darwin's ‘variables' from one generation to the next, all the variables have a chance of existing, some do, some don’t, a very Darwinian result. Darwin saw the tree of life in his theories of ‘evolution' & 'common descent' but the answer to 'blending' was not given to us by Darwin himself.
But the thing about the fight between Blending heredity & Mendel's heredity is the "it can’t be correct” bit. Darwin knew there was a problem, because he saw the black cats happening, but didn’t know how to solve it; Mendel proves ya gotta solve this before you can move on. (A bit like Galileo describing what was happening, and Newton explaining causal relationships.) This argument over time between Darwinian heredity & Mendelian heredity becomes the future of scientific enquiry. The importance of discourse, the importance of argument, the importance of testing your arguments to be true or false in the real world.
Mendel gives us the basis for genetic understanding of life on the planet & points us in the direction of the 'atoms' which will become fundamental to the theoretical understanding of the universe. His conclusions also leads to genes & the DNA which is the actual physical existence of the tree of life, actually present in all 'life' on the planet.
The Catholic Church in the Vatican was totally against this ‘argument' going on between these two scientists because it took out the concept of God from the equation. They could see what was coming.
Mendel was a priest & the attempt to shut him down got in the way of proper argument & scientific enquiry. Huxley presented Darwin’s ideas at Oxford, but Mendel’s stronger theories couldn’t happen, so the concept of 'atoms' & 'molecules' & 'genes', that form the basis of Mendel’s understanding of chemicals, had to happen later, in other places.
But these atoms & molecules identified later in chemical composition form the basis of understanding the whole of the universe, fundamental to astrophysics.
Like if in your chemical laboratory you identify oxygen O2 & hydrogen H2, & you have means of combining them to get water H2 O or separating them in water to get H2 & O2 & measuring their dimension & properties, & you look up into the planets or into the sun (like Galileo) & see evidence for the existence of one or both H2 & O2, you have to ask yourself why is it there? & where did it come from? This basic question is fundamental to astrophysics.
Along comes the mathematical physicist/engineer, they called 'Kelvin'. (William Thomson, 1st Baron Kelvin, Belfast, Northern Ireland, 1824-1907)
Kelvin goes back to the problem of how long the earth has been around.
Remember Newton the astrophysicist saying it had to be more than 50,000 years, hard to know, & Lyell the geologist saying what does it matter? It’s been around so long we can work under the assumption it’s been here forever? Different horses for difference courses.
Kelvin says you can’t do that because to understand the planetary make up of the earth (like Darwin & Mendel have been trying to do) and its place in the universe (Galileo, Newton) you need to understand where did it come from? And to know that you need to understand the timeframes.
To put this question about “how long?” on the shelf means you will never understand the problem proposed by Newton that was dismissed by the geologists as unimportant, you will never understand the universe, you will never be able to move on.
This the beginning of ‘time’ that we will see later in Rutherford’s 'half-life’ and Einstein’s theory of 'general relativity’, still to come.
Kelvin, looking at Newton’s surmising about how deep the crust is before you get to the bit inside that hasn’t cooled down yet, says you need to understand how long it has been giving off its heat. Kelvin says in order to understand how long the crust has been there I need to understand:
(1) how hot the earth was at the beginning (Newton's assumption);
(2) how heat increases as you go down into the earth (Newton’s problem with Galileo’s ball); and
(3) the rate the earth gives off heat (Newton’s cooling down).
This is the beginning of thermodynamics that is fundamental to astrophysics from then on.
Geologists sort of knew the answer to (2), heat increases 1 degree F every 50 feet you go down. Kelvin did some experiments to calculate (3) but (1) was difficult.
But he assumed it was around the point at which rock melts & becomes a liquid under intense heat. Looking at iron & other engineering results in the furnace he guessed that would be around 6700 degrees F at about 1860 miles below the surface. Newton’s 40 million feet diameter led to his calculation of the time for the earth’s crust 98 million years. (concluding the fireball with no crust to be somewhere between 20 - 400 million years) 420+98 = ~500 Kelvin used this & Laplace & Kant’s ideas to finally conclude the Sun had existed for no more than 500 million years.
This sent the scientific world into a spin. The idea that the earth and the sun had only existed for a short period of time was a bit like going back to the Christians’ “7 days”. The geologists were not prepared to accept any limitation. They wanted to assume ‘time’ was immemorial, to just get on with their job. But Kelvin could see the earth (& the sun) giving off huge amounts of heat over time & knew there was a limit.
In terms of the calculation, it seems Kelvin got it wrong because he assumed continuous warming from the crust down to Newton’s point at the centre of the earth where the ball he threw down would have a different impact from gravity going out the other side.
This was a big blunder, says Livio, if under the crust it was more like what was spewing out of a volcano. Kevin's blunder was not in the basic calculations of thermodynamics, which he got right, & forms the basis of modern science, but in not realising the full implications of his theory.
Irish mathematician/engineer John Perry (1850-1920) said that, if it was like hot water in a kettle, as Kelvin was suggesting from his calcs of the melting point of iron, it was more like 4 billion years.
Perry turned out to be much more accurate. But Kelvin was the scientist who provided the calculations as the terms for understanding these thermodynamic features of the universe, based on his understanding of the earth (and thereby, the sun).
Periodicity began with British chemist John Newlands (1839-1898) (Law of octaves) & German chemist Lothar Meyer (1830-1895) in the mid 1800s, talking about the relative atomic weight or 'valence' of basic elements. But it was Dmiti Mendeleev (1834-1907), a Russian chemist and inventor, who organised elements according to his Periodic Law and gave us the modern Periodic Table 1870.
His work led to an understanding of how basic elements in the universe related to each other & he even predicted elements that should exist but that had not yet been discovered.
Along comes a mathematical physicist in Scotland, James Clerk Maxwell (1831-1879).
Maxwell's most notable achievement was to formulate the classical theory of electromagnetic radiation, bringing together, for the first time, electricity, magnetism, and light, as different manifestations of the same phenomenon.
This gave Maxwell a direct wave to measure the speed of light against. He took Lalande's calculations of the distance between the earth and the sun of 153 million kilometres (±1 million km), and could finally correct Roemer/Huygen's speed of light to be approximately 186,000 miles per second (or approximately 300,000 kilometres per second). Modern calculations of the speed of light have gotten more & more precise, but this calculation has withstood the 'test of time'.
Maxwell's ground breaking work led to new scientists discovering radioactivity, a new source of heat, work by Curie, Laborde, Wilson, told us that decay in unstable atoms gives off particles & heat which came to be known as radiation.
Polish naturalised French physcist/chemist, Marie Curie (1867 - 1934). French pysicist Albert Laborde (1878 - 1968). Scottish physicist Charles Thomson Rees Wilson (1869 - 1959)
It didn’t take them long to realise that what was happening in the sun was something to do with this atomic radiation as unstable elements making up the sun broke down & gave off heat. This is at the turn of the century, so pretty amazing stuff. The geologists thought they had won. The universe, the sun, (the stars) could all have been around since the beginning of time.
In 1895 Wilhelm Conrad Röntgen German mechanical engineer & physicist, learned to detect & produce electromagnetic radiation in a wavelength range known as X-rays or Röntgen rays.
At the turn of the century New Zealand's physicist Ernest Rutherford (1871-1937) (the father of nuclear physics) comes along to make sense of these atomic particles and their break down & the heat generated. The radioactivity, that was being proposed.
He did a huge no of experiments & concluded that these radioactive elements contained an enormous amount of energy that could be released as heat. This was the beginnings of atomic weaponry & atomic power generation which came decades later.
Rutherford’s experiments into radioactive isotopes led to an amazing understanding of the ‘life’ of ‘un-living' objects on earth: now called “radiometric dating”. He found a radioactive element decays into another radioactive element (meaning it naturally gives off heat to become something completely different), each element having the same 'half life' that can be measured. So if one isotope changes into another & let's say emits half its heat in 11,000 years, the element it turns into will be half as radioactive as the first, but it will take 11,000 years to give off half *its* heat, and so on ad infinitum.
This gave Rutherford, working back, a precise measurement of 'time'. He has something real & present to measure time against.
This blew away the geologists because you could then measure the time that everything has existed, including the rocks, the crust, everything on the planet. It proved basically that Perry got it right & Kelvin got it wrong.
The geologists were given new tools to understand their discipline, but had to accept the beginnings of the earth & the beginnings of the sun and had the means to calculate it.
In the context of these readings, cosmologists like Einstein were trying to understand the space/time phenomenon. The geologists got their calculations by calculating distance between us & the sun & the time taken to cover that distance, 8 minutes and 20 seconds. But what does this reading seriously mean? In Newton's terms, for Maxwell's 186,000 miles per second to have any meaning it has to be a reading against something.
They say this new theory (which became known as 'relativity') came from a discussion between Einstein and John Milne.
British John Milne (1850-1913) was a geologist mining engineer heavily engaged in understanding the movement of the earth, and earthquakes around the world. His 'seizmology' was 'breaking new ground'. He gave us the seismograph.
Both Milne & German theoretical physicist Albert Einstein (1879-1955) were trying to understand the 'evolution' (i.e. using Darwin's basic elements) of the earth (Milne) and the 'evolution' of the universe (Einstein). Similar theoretical questions; similar attributes. When did it all start? How was it changing? How much time did we have? When will it all end? and how?
Taken from NobelPrize's 100 year celebration on Einstein's award https://twitter.com/NobelPrize/status/1370346593925406725
Einstein did his work using mathematical models which he called (following Milne's theoretical work on 'relativity' in seismology) (which follows the modern seismologist's Mohorovičić's theory of 'discontinuity') the 'theory of relativity', trying to generate a new theory of 'homogeneity' across the universe. He wanted a model that would explain 'time' wherever you are in the universe. A powerful tool allowing Einstein to explain what was being observed in the universe, unlike any other before him.
In 1905 (first Russian revolution) Einstein came up with a mathematical model that took this much further than Newton's planetary 'illusions'. Einstein called it his 'Special Theory of Relativity'.
Einstein's model set out to explain all time in the universe. He found there was nowhere you could look, no clock, that allowed you to understand the concept of time.
Just as Newton found, speed, time, distance, etc. are dictated by 'terms of reference'.
But the light coming from the the stars all over the night sky took time.
If light takes time, & that time can be measured to be finite, not infinite, then what time is, relates to its source & who sees it on the way.
This means, Einstein said, reality is absurd; if the laws of physics are the same in all frames of reference (and they are), and the speed of light, which is finite, not infinite, is the same for all observers, (regardless of whether you're standing in an immovable container on earth, in a speeding train, or some (what we now call a) spacecraft traveling to escape the earth's gravitational pull (at 25,000 miles per hour or flying to the moon in space at 3,158 miles per hour) (remember this in 1905 not 1968 Apollo 11's flight to the moon)) (and it is) then what we understand as 'time' is the element, the factor, that is changing.
They say Einstein woke up with this idea after dreaming of himself on a fast moving train & throwing Galileo's ball up & catching it without it being affected by the speed of the train (or maybe playing pool on a table on the train).
(Sounds pretty simple these days but in those days this simple concept changed everything we know about the universe.)
In 1915, Einstein took this one step further with his 'General Theory of Relativity'.
While everything he said in the special theory was true, it didn't tell the whole story because it didn't include (Newton's) 'gravity'. The pictures it gave us were particular to that person's 'terms of reference', so in a sense were just 'narratives'; pictures of different players experiencing (Newton's) 'illusions' at different speeds across the universe. Gravity is the constant factor in the universe. So if it's 'time' that is the variable, and you want to understand 'time', you have to include this constant factor (gravity), and then you would have a general theory that explains everything.
Einstein takes Newton's formula
(where F=force, m=mass and a=the amount of acceleration you need to get it to required speed)
& reworks it to include Roemer, Huygen, Maxwell, Rutherford, (like Einstein's famous formula
(where E=energy, m=mass and c=the speed of light)
is just Newton's famous formula, writ large, into all frames of reference)
and gives us a simple 'equivalence principle', which states that gravity pulling in one direction is equivalent to acceleration in the other. That is to say, if you are affected by gravity & you want to stay stationary, you would have to apply the equivalent amount of acceleration.
We experience this in a lift. When it accelerates up we feel gravity pulling us down. When it decelerates down we feel lighter, less gravity.
(While the lift is in free-rise or free-fall the Special Theory applies).
Newton knew this, (it is his 'equal & opposite' theorem) but following Einstein's Special Theory of Relativity, this simple concept had enormous implications. If gravity is equivalent to acceleration (Newton's 'a', Einstein's 'c') and c is finite & constant, then it means a massive (Newton's & Einstein's 'm') object like a star warps 'time' and space with its gravity.
Scientists have since observed the 'gravitational warping' of what we have come to know as space/time to prove Einstein's new definition of 'time' to be true. It is undeniable.
We know that time passes faster in orbit than it does on Earth because we've compared clocks on Earth with those on orbital satellites farther from the planet's mass. Scientists call this phenomenon 'gravitational time dilation'. (And today these satellites are so important to communication, safety, security, location, even movement from one location to another on earth, that nothing on earth would function, even the drones, if time dilation wasn't written into their basic designs). Likewise, scientists have observed straight beams of light curving around massive stars in what we call 'gravitational lensing'.
But Einstein including gravity in the General Theory of Relativity didn't come without its problems.
Einstein's quest for 'homogeneity' was difficullt to maintain. In 1917 (Russian revolution) the knowledge of the universe was limited. Observers thought the universe might only be what we could observe, meaning the Milky Way. So, galaxies, as we know them today, were meaningless. They hadn't yet been 'invented'. The Milky Way *was* the universe. And when you look up into the Milky Way you see huge areas of 'closeness' between the stars & huge areas of 'nothingness' (going aginst the 'uniformitarianism' we had come to expect) in this 'universe'.
This meant that Einstein's theories were suggesting that, with those limitations, the universe would be impacted by (Newton's) gravity and stars would soon come moving back into the nothingness, crashing into itself as the stars emitted their energy/heat & became less massive (Newton).
But Einstein could see no evidence for this happening and so was committed to a stable cosmos. There was an amazing uniformity in the relationship & the movement between the stars. So he needed a repulsive force that would keep gravity at bay, which became known as Einstein's 'cosmological constant' (bit like Kelvin's 'ether'). Somehow this constant was supposed to give us exactly what we needed to have a stable universe.
(This is a bit like Darwin's problem which was like since there is no plan in the mind of God it cannot be teleological. Remember Darwin took out the concept of God planning everything, so if going forward something fails, & you want it to be (Darwin's 'stronger') (Einstein's 'stable'), you would have to have at your disposal, exactly at that time, exactly what you need to make it (stronger/stable). This was Darwin's mistake that Mendel solved.)
In 1918 (end of WWI) German theoretical physicist Max Planck (1858-1947) was awarded the Nobel Prize for his discovery of energy quanta.
Energy quanta is 'looking' at the smallest particles that make up the universe (a bit like Rutherford's radioactive isotopes) like X-rays, (like, later, Ryle's radio waves), etc., which can only be measured in certain packets (quanta). But 'looking' is theoretical. In order to 'understand' these particles we may try to shine light on them to measure their strength or their position but these quanta are so small that, if we do that, we will cause their strength or their position to change in arbitrary or unknowable ways. (Planck hypothesis)
In the 1920s C.V. Raman (1888-1970), using very simple ideas & simple technical instruments, began the reality of 'looking'. He was the first to use Planck's quantum theory in the real world. Until Raman it had been accepted (since 1918), but had no way of being proven. He turned his study of sound from the traditional Indian instruments into a way of studying and understanding light, & thereby the molecular structure of 'everything'.
Raman's idea itself was very simple. Atoms & molules themselves emit radiation (or light). He and his team at Calcutta university proved this to be the case by observing how light travels through water, or many other (or any other) material(s). Take a look at how light changes its colour when going through water he said & you are met with an unarguable result that something must be happening to that light when it comes into contact with the atoms/molecules that that water is made up of. This was already observed in the sky (Raleigh) as light turns the sky blue but it was assumed that the molecules in the sky were simply changing the direction of light as it comes into contact with them (diffraction). But the idea that the atoms in the water itself were emitting light was very new to science & it changed the nature of scientific endeavour forever.
For a great description of the discovery of the 'Raman effect' see:
The Raleigh effect was already known. Shine light through a prism, says Raman, & it breaks up into different colours according to the wave lenth required to generate that colour.
But take some of that light, like the violet light & scatter it, by, say, passing it through water & collect it again, what you get back should be violet. But it isn't says Raman; it changes colour.
In simplistic terms, he took the violet light collected from the scatter, put it through a filter designed to block the violet light, & he still had light left over. This means that he got out more than he put in. Only a tiny effect, like 1 part in a million, but the fact that there was any light at all means that the atoms/molecules in the liquid that it passed through emitted light in reaction to the violet light. An added 'effect'.
It was difficult to calculate the exact or precise level of the Raman effect because it was so minute, a 'quantum' of light. Raman improved that by finding ways to make the light he was working with more intense & inventing new means of observing & calculating the results.
It was only after the invention of LASER (Light Amplification (by) Stimulated Emission (of) Radiation) technology in the last decade of Raman's life that the full impact the Raman efffect became precisely calculable.
Planck's theorem, & Raman's proof, gave rise to Heisenberg's 'uncertainty principle'. Werner Heisenberg (1901-1976). This uncertainty principle (1925) has become central to science and today's world. While it was rejected by a key physical analyst in its formation, Einstein himself, uncertainty is now fundamental to science & to the design & technology of today's world, quantum mechanics.
At the same time Wolfgang Pauli (1900-1958) gave us his 'quantum numbers principle' (1925) (AKA the 'exclusion principle') which proved that if quantum numbers were assigned to electrons' distinct state of energy & movement, no two electrons would have the same number.
It was later discovered that protons and neutrons in nuclei could also be assigned quantum numbers and that Pauli's principle applied here too.
As technology improved, the immense character of the universe started to become apparent. Trillions of stars in billions of galaxies, limited only by what we could see. With lots of 'nothings' in between. Einstein realised the 'cosmological constant' was unnecessary & meaningless.
But it didn't solve the 'teleological' problem. If everything was stable, we still needed to understand why this is so. Ya can't just abandon the assumption and move on. As Kelvin proved, scientific discourse can't work like that.
A lot of work was necessary to put that to bed.
The astrophysicists around the world, looking up at the universe, at the trillions of stars, the billions of galaxies, collecting their observations, said that there is a huge homogeneity (which is what Einstein had beeing looking for) when you look at the universe in any direction. This was unexpected. There were small groups and big clusters of stars and galaxies, yes, but if you look at the universe in any direction you basically see the same thing.
In reaction to this new form of 'relativity' (a bit like Newton's geologists' 'uniformitarianism') there were important theorists, the Belgian priest Lemaître, Hubble, Hoyle, Bondi, Gold. Their discussions were about why should this be? (It solved the 'stabilty' question, but not the 'teleological' one.)
The discussion would probably have been something along these lines: If we look out in every direction & basically see the same thing, there can only be two basic explanations:
(1) we are either at the 'absolute centre' of a very complex & similar structural pattern of astral formations, or
(2) it matters little where we are in the universe, if we were to look out from another random space/time in the universe we would basically see the same as we are seeing at this moment of space/time.
Observations since the days of Copernicus, & especially since the discovery of the galaxies & the particularity of the Milky Way, tells us that it cannot be (1). The earth is a small planet in a small solar system orbiting around a dwarf star on the edge of a medium sized galaxy, in a universe made up of billions of galaxies.
It is not the centre of the universe.
To assume that it is is to take us back to the Christian nonsense of God created the earth in 7 days, the sun on the 4th day, & everything in the universe is in spheres around the earth, the nonsense that Copernicus proved to be wrong & which the millions of observations since his time have verified to be false.
So it must be something like what (2) suggests, a form of (Lyell's) uniformitarianism. But what does this mean? & how could that be?
Austrian/British Hermann Bondi (1919-2005) attempted to solve this question with his steady state theory, developed in collaboration with Hoyle & Gold. The universe is as it has always been; it just is. We see the same thing from every place in the universe becuase that is what a universe is. We observe change in the universe but that change is compensated by similar change in other places in the universe, because overall the universe is, and must be, in a 'steady state'.
This is of course a theme we have see coming up again & again. It is a bit like Darwin's problem of an assumed teleological outcome. If there is no god and you assume a 'steady state', then you need a theoretical construct that will explain that steady state, insurmountable, for all time. It cannot simply be assumed. Not an easy undertaking.
Similar to Kelvin's adopting the task to question the assumptions of the geologists & disprove them. Bondi was on unsteady ground. He had not eliminated the problem of Einstein's cosmological constant. He was simply restating it in another form. It is like Darwin's survival of the fittest, if you survive you are the fittest, purely an assumption; unscientific. And this was made even more improbable following developments in quantum mechanics & Heisenberg's uncertanty principle.
Belgian Catholic priest Georges Lemaître (1894-1966) was a Professor teaching mathematics, physics, astronomy at a Catholic Uni.
In 1927 Lemaître started to solve Einstein's cosmological constant or Bondi's steady state with his concept of the 'big bang'. For Lemaître we see the same thing in every moment of space/time in the universe not because we are the centre of the universe but because the universe itself had started at a single point and had exploded violently at immense heat to its current shape, size, heat, space/time.
Looking back, it might not seem surprising that this idea for the beginning of the universe should come from a person engaged in the study in whose life there is a god. But, similar to the work of the priest Mendel, his work as a scientist allowed him to solve many of the riddles that the work on astrophysics had given rise to, and didn't get in the way of, pure mathemetical theorems that didn't require (& has never required going forward) a theological approach to make sense of the 'beginnings of the universe'. The early conversations of Darwin & Mendel had developed a rigour that has been maintained ever since, in which God plays no part.
An early advocate of Lemaître's theoretical model was Russian born George Gamow (1904-1968), who started working with Rutherford on radioactivity, but who later moved to the US & devoted much of his time on making sense of Lemaître's big bang theory.
The big bang solved the uniformitarianism problem. But it didn't solve the teleological problem. If the universe had started at a single point & is now in its current state, how could it have reached its current state in space/time? (Einstein's 'homogeneity problem' the cosmological constant was introduced to solve.)
Just two years after Lemaître's break through on the big bang (1929) (the Great Crash & beginning of the Great Depression), American astronomer Edwin Hubble (1889-1953) discovered that, in fact, the other galaxies were moving away from us. This meant that the universe was still expanding. This got rid of the teleological problem. It hasn't yet reached its 'current state' because it is still expanding. And it justified & proved Lemaître's model. If things are moving apart, it meant that long ago, everything had been close together.
And that’s not all, said Hubble; the farthest galaxies from us are moving faster than the ones closer to us.
It's as if the 'nothing' that Newton had discovered meant that there are no, and there never will be, 'boundaries' to the universe. All the billions of galaxies are like on a balloon that is being pumped up, and this expansion is getting faster as 'time' goes on.
This current expansion between galaxies is not happening because of outward pressure going in all directions from (Lemaître's) explosion at a central point, which you would expect to decrease as 'time' goes on, which is the way we experience an explosion here on earth. If things happened like that in space it would bring back Einstein's need for his cosmological constant to stop everything come crashing back in on itself. It is more like the huge collection of mass (Newton's, Einstein's 'm') at some point after the big bang settled down and began falling outwards into (Newton's) 'nothing'.
It works differently to the 'encirclement around the sun' described by Newton, determined by gravity. Galaxies do that, because of gravity, but with the balloon of 'everything' there is no boundary, no 'crust' if you like (Newton, Kelvin, Perry), so the expansion is never ending.
And why is the rate of expansion increasing? Well, says Hubble, look at it this way, all galaxies in the universe have their own baloon. If we in the Milky Way look in any direction we see all the galaxies on the other side of the balloon moving away from us and the further away they are, the faster they 'appear' to be moving because the distance between us and them is getting larger 'both ways' (that is to say, the distance between us & 'them' is doubled from the centre of the balloon, if you know what I mean) (a bit like Newton's 'illusion' giving us an insight into the 'reality' of the cosmos). This 'illusion', as in the case of Newton, leads us to the 'reality' of a faster expanding universe. Each galaxy 'falls away' from each other galaxy, because there is no boundary, and, as galaxies get further & further apart, the gravitational pull between them gets weaker, so they fall even faster.
English astronomer Fred Hoyle (1915-2001) working alongside Einstein in the late 1930s (as the Nazis were building up their control of Europe, and burning books), took astrophysics in a new direction.
Prior to Hoyle everyone thought that all the elements that we see around us today, given to us by the experiments in the chemistry lab, such as Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine etc. elements necessary for life as we know it, and also elements for the half-life in the atomic world that Rutherford identified, & proved by experiment, all came from the big bang.
That huge explosion at the highest heat possible was expanding out into space (Newton's nothing) subjecting what it was made up of to small amounts of ‘difference' & it was those ‘differences', the astrophysicists supposed, that gave rise to the atoms & the different elements, atoms fusing into bigger and bigger compounds under slightly different heat and pressure.
As the big bang theory dominated thinking, astrophysicists started to see this ‘periodicity’ in temporal terms, the smaller younger ones like Hydrogen changing to helium, to bigger ones as these came together, and so on, as the big bang continued out, taking 'time' (a 'period') to do so. (Could have worked in the opposite direction, there was no way to know).
We know today from our current ‘periodic' table that there are at least 118 basic elements with different impact on the universe because of their higher & higher mass as you go up 'the table'.
Modern astrophysicists looking at our sun & the stars looking into the telescope (similar to what Copernicus & Galileo & Newton had been doing) could see some of this happening in our current timeframe, like hydrogen changing into helium under massive heat in our own star (the sun). But found it difficult to explain the other larger (heavier) elements, like carbon and metals, and so the idea they have all been around since the big bang (bit like a newer version of the 'ether'), continued.
But Hoyle reckoned that this homogeneity could not be just relied on as an assumption (Kelvin). You had to look at it and see what was really going on (as Kelvin said before he discovered thermodynamics). Hoyle used thermodynamic calcs to understand how extremely massive the heat at the core of a massive star, what we now call a Supernova, was. He saw the explosions of the atomic weaponry here on earth during the war, he saw the hydrogen turning into helium in the sun by (atom-ic/hydrogen-ic explosion) (Curie, Laborde, Wilson).
But at a billion degrees or so, he saw in the Supernova, Hoyle assumed atoms would explode (as they do in an atomic bomb), and, at that level of heat caused by their intense gravitational intensity, their explosion would break up other atoms ad infinitum until they went into what he called 'atomic equilibrium', homogeneity in another form, a bit like what previous scientists had supposed about the big bang, occurring before the differences started to take hold. At a billion degrees, he assumed, they had nothing to cool them down, which limits what happens from an atomic bomb here on earth, or even in the millions of degrees in the Sun.
Their being all broken up like that, he assumed, when they started to emerge, getting back together again, they could come together as different elements, based on the differences in the heat/gravity on them at the point of compound, as they emerged from the centre (Newton).
He had no way of calculating it. But information helping him do his calculations came from those developing the atomic weapons used in Japan, & only came to him at the end of the war.
His calculations suggested carbon, oxygen & iron, necessary for life on our planet, had not always existed; they began, not at the moment of the big bang, but came to 'life' in the nuclear explosions happening in the intense gravity of massive stars. (This solved the problem of the lack of evidence for periodicity emerging from the big bang. The homogeneity of the big bang, experienced by the astrophysicists, was real, he suggested. The lack of evidence for the periodicity was real, because there was very little, from the big bang. It was happening long after the big bang, in the 'birth' of the Supernova, the 'life' of the Supernova, and the 'death' of the Supernova.)
Others took up his ideas but were proving that the transformations would happen too quickly, too unstable, that there was not enough 'time' to get to the bigger elements like carbon.
That's true, said Hoyle, in normal stars, but in supernovas, things would be different. He said, at that level of gravity/heat, they had all the time they needed to come together as different compounds as they emerged from (newton's, kelvin's) centre to the surface (perry). He did his calculations, but he needed proof.
Everyone thought he was off his rocker, in his own little world, but they said, oh alright then, let’s give him a bit of time in the observatories to play his silly games.
Observers have a way of calculating and observing compounds. Hoyle told them where to look to find them. They looked; they found them.
To their amazement his prediction turned out to be proven by experiment, & the whole of astrophysics changed. Hydrogen, helium, the smaller elements were coming at us from the small stars. But from a massive star the full she-bang was available at an arbitrary statistical certainty. The full chemical periodicity was not created by God but by (Darwin's) 'evolution' taking place in massive stars.
Hoyle also gave us a picture of the internal structure of a pre-Supernova star that was not unlike the Christians' spheres surrounding the earth, each sphere giving us different compounds of heavy metals, & including (Newton's, Perry's) 'crust', etc. depending how hot (how close to the (Newton's, Kelvin's) centre of the Supernova you are). All of which could not be explained before Hoyle came on the scene.
Rather than collapsing into a 'dwarf', as the small burnt-out suns do when they give off all their heat, and their (Newton Kelvin's) 'crust' pushes in because of the crush of gravity, Hoyle says, the Supernova with its intensity at (Newton's) centre is likely to explode (like an atom bomb) because it has no (Newton) 'ether' holding it back, throwing all the heavy metals out into the universe, to be available for coming together, combining, to create our asteroids, our comets, our earths, our moons, etc. These are also there for collection in much larger amounts that get hotter & hotter as they accumulate, to create the smaller suns, and 'evolution' starts again.
This meant that Hoyle, looking at (Lemaître's, Hubble's) expanding universe, since he had proven heavier metals were 'created', assumed that there had to be something that kept the universe in a singularity, a stable condition, similar to his 'atomic equilibrium', which we could assume to be the point at the moment of the big bang.
But of course we know that there is going to be problems with this. We have seen clear thinkers again and again fall into this trap of assumed teleological equilibrium. If there is no god and you assume atomic equilibrium, then if an atom ceases to exist for whatever reason, there must be something in the structure of the universe, its means of creation, its space-time reality that brings into being a new atom at precisely that space-time you need it to maintain that equilibrium.
While the big bang seemed to be saying that everything came from nothing, the idea that particularity needed to keep the universe stable could come from nothing over time as the universe expanded was difficult to stomach (a bit like Darwin's theory of species getting more able to survive over time) and a big dispute between two schools emerged (a bit like the geologists vs. Kelvin/Perry on whether the earth had been around since the beginnings of 'time').
This was like 'cosmological constant, (Einstein); 'steady state' cosmology (Bondi) now 'singularity' (Hoyle) vs the 'big bang' theory (Lemaître, Gamow). Along comes British astronomer Martin Ryle (1918-1984). Ryle's 'radiology' said if we were in 'steady state' (Hoyle) it didn't matter how far away the galaxy was or how it was expanding we would get the same radio reading, not younger getting older.
Ryle did his tests (a bit like Rutherford's tests of the atomic half-'life' of 'everything') & found higher radio, quasars in the past, lower in the present, proving Hoyle wrong. The universe was evolving. (Darwin)
After that Bondi, in a Darwin fashion, went looking for 'fossils' showing what the universe contained in the past. If it was 'evolving' (Ryle) he said, he would find them. And he found them: The main fossils were Helium abundance (from Hydrogen in the big bang, as we see in our sun (Hoyle)) & a 'cosmic background' (a bit like a 'glow' in every direction, left over from the big bang) telling us the 'big bang' had happened and its impact is still with us.
These are the major steps that bring us to the astrophysicists of the modern era. The key players in today's world to date, influencing scientists around the world, have been Friedmann, Penrose, Hawking regarding the 'birth' & 'life' & 'death' of galaxies and, associated with that, the 'birth' & 'life' & 'death' of 'black holes' & the future of the universe, that somewhat go together, and Planck & Heisenberg on the extremely small elements that impact on everything above, from the big bang to the present, called 'quanta'.
A 'black hole' is a place in space where gravity causes mass to come together so intensely that it goes towards a single point. This can happen when a dying massive star (like Hoyle's supernova) explodes & then collapses in on itself. With all that mass in such a small place, gravity becomes so intense that even light cannot get out.
Because no light can get out, a black hole is, in a sense, invisible to the observer, hence its name. But they were known to exist from modelling. And space telescopes with special tools were designed to help find them. That is to say, the observer can now see a black hole based on the movement of light (Einstein's space/time expectations based on the general theory of relativity vs what we actually observe) and how stars that are very close to black holes act differently than other stars as they move across the sky of the observer, for example a close star may appear to be at one place in the sky when light is coming at us from one side of the black hole and at a totally different place when on the other side of the black hole (the impact of a black hole on light travelling to earth (Einstein's space/time)) (a bit like Newton's 'illusion' showing us the reality of 'life' in the universe). Or, when a star comes close to a black hole, huge emissions of light (like sparks millions of miles in diameter lighting up the sky) can occur showing us the place & the dimensions of a black hole.
A huge black hole has been found at the centre of our Milky Way and they are thought to be central to the formation & existence of galaxies across the universe. Tiny black holes are thought to have been formed at the time of the big bang. Huge (supermassive) black holes were a paramount feature of the formation of galaxies.
' Life' of the universe from big bang to now - our own supercluster is dissolving, the role of dark matter in working against mutual attraction of galaxies, clusters, superclusters, groupings https://medium.com/starts-with-a-bang/our-home-supercluster-laniakea-is-...
Vera Rubin, constant rate of spiral of galaxies, the existence of dark matter https://www.nature.com/articles/d41586-021-00734-4
Astrophysics is today highly influenced by Penrose's/Hawking's attempts at generating a general theory of 'everything', similar to Einstein's general theory of relativity.
The search for exoplanets, understanding their character & the search for life on exoplanets (life outside the earth) is dominating modern thinking & the search for the galaxies, back in time.
our neigbourhood = 10 parspecs (33 lightyears)
375 stars (249 red dwarfs, 21 white dwarfs, 18 G-types, 2 stellar systems (5 stars each)), 88 brown dwarfs (identified to date), 77 exoplanets (to date)
Recent (2021) discoveries show that earth's crust (Newton, Kelvin, Perry) has been around for at least 3.7 billion years. By measuring strontium (Rutherford) isotopes in barite minerals weathering into the sea (the source of life in the oceans), Bergen geologists were able to determine the age of these minerals as ranging from 3.2 to 3.5 billion years. This means that the continental weathering process probably started around 3.7 billion years ago, they said. A final absolute proof of Perry's case against Kelvin on the age of the earth & its crust some 126 years later.
Interesting bits & pieces on astrophysics
Martin Rees & Mario Livio (2021) https://nautil.us/issue/97/wonder/if-aliens-exist-heres-how-well-find-them
Water & organic material evolve from an asteroid in the solar system https://theconversation.com/how-asteroid-dust-helped-us-prove-lifes-raw-...
The Penrose stairs & Escher's fish https://play.acast.com/s/nobelprizeconversations/rogerpenrose-nobelprize...
Work continues on Hawking & black holes - Lab grown analog https://www.space.com/black-hole-analog-confirms-hawking?utm_source=twit...
The realities of #exoplanets https://astronomersforplanet.earth/
big bang theory
Bondi - steady state theory
calculating the beginnings of the earth - Kelvin
calculating the beginnings of the earth - Newton
calculating the beginnings of the earth - Perry
calculating distance between sun & earth - Huygen
calculating distance between sun & earth - Lalande
calculating distance between sun & earth - Maxwell
calculating distance between sun & earth - Roemer
calculating size of Solar System - Halley
earth's heating & cooling - Newton
Einstein - cosmological constant
Einstein - general relativity
Einstein - special relativity
electromagnetism - Maxwell
evolution - Darwin
exoplanets - finding life in the universe
expansionism - Hubble
Friedmann/Penrose/Hawking - black hole
Gamow - big bang
general relativity - Einstein
general theory of 'everything' - Hawking
general theory of 'everything' - Penrose
gravity - Galileo
gravity - Newton
gravity is constant
Halley - parallaxism
Hawking - black hole
Hawking - general theory of 'everything'
heating & cooling - Newton
Heisenberg - the beginnings of quantum mechanics
Heisenberg - uncertainty principle
homogeneity - Lemaître/Hubble/Hoyle/Bondi/Gold
Hoyle - periodicity
Hoyle - singularity
Hoyle - supernova
Hubble - expansionism
isotopes - Bergen
isotopes - Rutherford
Kelvin - thermodynamics
Lalande - parallaxism
Lemaître - big bang
life in the universe - exoplanets
mass - Newton
Milne - relativity
Maxwell's electromagnetism & the speed of light
observation - Galilieo
observation - Lemaître/Hubble/Hoyle/Bondi/Gold
parallaxism - Halley
parallaxism - Lalande
Penrose - black hole
Penrose - general theory of 'everything'
periodicity - Mendeleev
periodicity - Hoyle
Planck - quantum hypothesis
quantum exclusion principle - Pauli
quantum hypothesis - Planck
quantum hypothesis - proof - Raman effect
quantum mechanics - Heisenberg
quantum numbers principle - Pauli
quantum uncertainty principle
radiation - Curie
radiation - Laborde
radiation - Wilson
radioactivity - Rutherford
radiology - Ryle
Raman - proof of Planck's quantum theory
rays - Roumgen
relativity - Newton
relativity - Milne
relativity - Einstein (special)
relativity - Einstein (general)
Röntgen - rays
rotation - Copernicus
Rutherford - radioactivity
Ryle - radiology
singularity - Hoyle
special relativity - Einstein
speed of light - Huygen
speed of light - Maxwell
speed of light - Roemer
steady state theory
testing the speed of gravity - Galileo
thermodynamics - Kelvin
thermodynamics - Newton
thermodynamics - Perry