Posts Tagged ‘‘A Brief History of Time’’

Physics Textbook on Cosmology and Gravitation

March 15, 2018

M.V. Berry, Principles of Cosmology and Gravitation (Bristol: Institute of Physics Publishing 1989).

Yesterday came the news of the death of the great British physicist and cosmologist, Stephen Hawking at the age of 76. Hawking had suffered for most of his adult life from motor neurone disease, since he was diagnosed with it in his early 20s. He was given only three years to live, but instead managed to live out a very full lifespan working on his theories of the origin of the universe and Black Holes. He was a great ambassador for science. His book, A Brief History of Time, was a bestseller when it appeared in 1980s, although he admitted that it was probably a book few finished. And he showed that it was still possible for a disabled person to do cutting edge research, provided they had the necessary technical and medical support. In his case, it was his wheelchair and the machine that allowed him to speak, first of all by keying in the words, then by twitching just a single muscle. Some of the praise seemed a bit too fulsome to me. Like when they started saying that he was the greatest scientist since Newton and Einstein. I don’t think he was. And Hawking on his own didn’t unlock the secrets of universe or Black Holes, as the Beeb’s presenters also claimed. As for his great sense of humour, well, it existed, as his appearance on shows like The Simpsons demonstrated, but my memory of it is marred by him turning up with the TV critic, Victor Lewis Smith, telling fart jokes and laughing on the 1990s series, Inside Victor Lewis Smith. But it really was inspiring to see how he was a great hero to the ‘A’ level students at a science fair yesterday, and how he had inspired them to become interested in science.

One of the complaints Richard Dawkins has made about popular science programmes is that they’re too ‘dumbed-down’. He points out that they have to have lots of explosions, and they mustn’t include equations, in case that scares people off. There’s a lot with which I don’t agree with Dawkins. I’m not an atheist, and have argued on this blog against him and the other militant atheists. But he is right here. Scientists writing the popular science books have said that they’ve been told by their publishers to leave equations out, because every equation in a book damages sales.

I think this is the wrong attitude to have. It’s why I’ve put up this piece about the above book by M.V. Berry. It’s an undergraduate physics textbook, which does contain the fundamental mathematical equations for this area of physics. Its contents include

1. Introduction

2. Cosmography
2.1 What the universe contains
2.2 The cosmic distance hierarchy and the determination of galactic densities
2.2.1 Parallax
2.2.2 Distance from velocity measurements
2.2.3 Distance from apparent luminosity
2.2.4 Weighing galaxies
2.3 The red shift and the expansion of the universe.

3. Physical base of general relativity
3.1 The need for relativistic ideas and a theory of gravitation.
3.2 Difficulties with Newtonian mechanics: gravity
3.3. Difficulties with Newtonian mechanics: inertial frames and absolute space.
3.4 Inadequacy of special relativity.
3.5 Mach’s principle, and gravitational waves.
3.6 Einstein’s principle of equivalence.

4 Curved spacetime and the physical mathematics of general relativity.
4.1 Particle Paths and the separation between events
4.2 Geodesics
4.3 Curved spaces
4.4 Curvature and gravitation.

5 General relativity near massive objects
5.1 Spacetime near an isolated mass.
5.2 Around the world with clocks.
5.3 Precession of the perihelion of Mercury
5.4 Deflection of light
5.5 Radar echoes from planets
5.6 Black Holes

6 Cosmic Kinematics
6.1 Spacetime for the smoothed-out universe
6.2 Red shifts and horizons
6.3 Apparent luminosity
6.4 Galactic densities and the darkness of the night sky.
6.5 Number counts

7 Cosmic dynamics
7.1 Gravitation and the cosmic fluid
7.2 Histories of model universes
7.3 The steady state theory
7.4 Cosmologies in which the strength of gravity varies

8 In the beginning
8.1 Cosmic black-body radiation.
8.2 Condensation of galaxies
8.3 Ylem.

Appendix A: Labelling astronomical objects
Appendix B: Theorema Egregium
Problems
Solutions to odd-numbered problems
Useful numbers.

there’s also a bibliography and index.

I’m not claiming to understand the equations. I struggled at both my ‘O’ level maths and physics, and what I know about science and astronomy I learned mostly through popular science books. But in the mid-1990s I wanted to see at least some of the equations scientists used in their explorations and modelling of the universe. One of the popular science books I was reading said at the time that this book was at the level that people with ‘A’ level maths could understand, and this didn’t seem quite so much a jump from my basic maths skills. So I ordered it. I’m afraid I can’t say that I’ve read it properly, despite the fact that I keep meaning to. Some of the equations are just too much for me, but I can follow the explanations in the text. I’m putting this notice of the book up here, in case there are any budding Stephen or Stephanie Hawkingses out there, who want to go a bit further than the pop-sci explanations, and see for themselves what the maths behind it all is like.

The Beeb also said in their eulogy for the great man, that Hawking hoped that the people reading his A Brief History of Time would come away with one point, even if they hadn’t finished it: that the universe is governed by rational law. Actually, this ideas isn’t unique to Hawking by a very, very long way. It actually comes from the Middle Ages, and is the assumption that makes science possible. Hawking was an agnostic, I believe, and many scientists are atheists. But this assumption that the universe is governed by rational laws ultimately comes from Christian theology. The founds of modern science in the Renaissance pointed to the passages in the Bible, in which God’s Wisdom creates the universes and establishes the boundaries and courses of natural phenomena, like the tides and stars. And the anarchist of science, Feuerabend, pointed out that the assumption that the laws of the universe all form a consistent whole come from Christian doctrine, quoting the 13th century theologian and philosopher, Thomas Aquinas: ‘We must believe that the laws of the universe are one, because God is one.’

Hawking has passed away, but it’s clear that he has inspired many more people to become interested in this rather arcane branch of the sciences. I hope this continues, despite the Tories’ attack on education and science and research for its own sake.

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Stephen Hawking’s Defends NHS as Hunt Lies about its Privatisation

August 22, 2017

I know the Tories will immediately complain about the title of this article, but that’s exactly what’s going on. The Tories have been privatizing the NHS piecemeal since the 1980s, when Maggie Thatcher wanted to sell it off completely and replace it with an American-style insurance based system. Thatcher was prevented from doing so through a massive cabinet revolt, plus the fact that her private secretary, Patrick Jenkin, found out how appalling the American system was after he actually did some research and went there.

But the privatization is still going on. There was a mass exodus of dentists in the late ’80s-early ’90s, after Maggie – or was it Major?-refused to give them any more money. Then came Peter Lilley and his Private Finance Initiative, in which hospitals were to be built and run for the NHS by private contractors. Then New Labour expanded this massively, breaking up the NHS internal structure to model it after the American private healthcare system, Kaiser Permanente. Blair was approached by a whole slew of American private healthcare companies. His idea was that hospitals and clinics should be taken over by private healthcare companies, like Circle Health, Virgin Healthcare and so on. The community care groups of doctors, which were supposed to commission healthcare for their patients, where to obtain it from both private healthcare providers as well as the NHS. And they were also given the powers to raise money from private enterprise.

And before anyone objects that Blair was a Socialist, no, he wasn’t. He had Clause 4 removed from the party’s constitution. He was also profoundly hostile to the trade unions, who have formed part of the very core of the Labour party since it was founded in the very early 20th century.

Blair was a true, blue Thatcherite. The first thing he did when he got into power was invite Thatcher round. And she responded warmly, declaring New Labour her greatest success. Remember, this is the woman, who proudly shouted about how she was going to destroy socialism.

And the Tories have carried on her project of gradually destroying the NHS, bit by bit, while loudly proclaiming how much they’re in favour of it.

The present Health Secretary, Jeremy Hunt, is a prime example of this. He even wrote a book in which he declared how much better everything would be if we had a private healthcare system, like America.

Yeah, like America, where the poorer parts of the country don’t have any doctors at all, because it isn’t profitable. Where once a month, in Virginia, people sleep in cars overnight in order to join the queue for the doctor’s or dentists’ surgery offering free dental care that Saturday.

Where something like 20 million Americans can’t afford their medical coverage, and 30,000 people die every year because of this.

And where the Republicans and corporate Democrats have been lying and smearing Bernie Sanders, because he dared to run on a platform of ‘Medicare for all’. You know, giving Americans state-funded healthcare, like in the other parts of the world.

This is what the Tories are doing to Britain. And last week, as Mike reported on his blog, Stephen Hawking, the great cosmologist, called them out on it. He also accused Hunt of cherry-picking the data about the supposed deaths caused by NHS staff not working Saturdays.

Hunt got terribly upset about this, and declared that Hawking didn’t understand statistics.

This is a joke from a professional moron. Statistics are a vital part of science and medicine. Much of modern science, including astronomy and cosmology, is going through the data, trying to find something that is statistically significant. It can be time-consuming, tedious work, requiring sophisticated techniques to sort out what’s importance from apparently random results.

Hawking’s a physicist, who has been working with some extremely advanced maths as part of his investigation into the origins of the cosmos and the nature of Black Holes for his entire career. I don’t believe in his ‘No Boundaries Solution’ to the problem of the origin of the universe, but it’s abundantly clear that he understands stats. And as a man stricken with Motor Neurone Disease, a terrible illness, which has left him confined to a wheelchair, unable to speak and scarcely a muscle, Prof. Hawking clearly has first-hand experience of NHS care.

In short, don’t believe Hunt. Believe Hawking.

And yesterday one of the doctors weighed in, to request that a televised debate should be held between the two. See that story on Mike’s blog.

I’ve got no doubt that this will never happen. The schedules are full already, and the last thing the Tories will want is putting their man in a position where he’ll lose against a vastly more popular, far more respected and definitely more intelligent opponent.

Although they’re both authors. Hawking’s most famous work was A Brief History of Time, published back in the 1980s. It was a national bestseller, following very much in the footsteps of Carl Sagan’s epic Cosmos, another pop-sci blockbuster from a great science communicator, as well as a concerned scientist who attacked militarism, imperialism and man-made global warming.

As for Hunt, very few have read his book, which is why he can still repeat the lie that the Tories aren’t privatizing the NHS with a straight face, despite having advocated himself.

Such a debate would be so unequal in Hawking’s failure that I’ve no doubt that the Tories in charge of BBC News, the same people, who gave Corbyn such overtly biased coverage during the general election, are blanching at the very thought of it. Such a debate will never happen, just as the BBC will never own up, and confess that they, and particularly Laura Kuenssberg, are massively biased and everyone, who has complained about this painfully obvious fact is absolutely right.

Stephen Hawking and Other Celebs Urge Public to Vote Labour

June 6, 2017

Mike over at Vox Political has put up a piece reporting that Ricky Gervaise, Dr Stephen Hawking and Mark Ruffalo, the actor, who played Dr. Bruce Banner, the alter ego of the Incredible Hulk, have all urged the public to vote Labour on Thursday.

Gervaise issued a Tweet stating he wasn’t telling people which way to vote, but it was a fact that the only way to keep the Tories out was to vote for Jeremy Corbyn.

Mark Ruffalo stated that he humbly endorsed Jeremy Corbyn, as he offers people an alternative to the corporate status quo, which never ends well for people. This prompted John Prescott to Tweet ‘Hulk smash Tories’.

Indeed he would. Banner and the Hulk in the original Marvel comics were profoundly countercultural figures. The Hulk was anger incarnate, born in the radiation blast of an American nuclear test when Banner tried to save teenager Rick. And Rick was very much a ‘rebel without a cause’, a youth, who’d driven into the test zone, heedless of his own safety, because he didn’t feel society had anything for him.

While Banner was very much a square, whose girlfriend was the daughter of the commanding officer in charge of the test, the tenor of the strip was very much anti-militarist. The commanding officer hated the Hulk, and had resolved to destroy him. The Hulk, however, really only wanted to be left alone, and so one constant theme was the running battle between the Hulk and the US army. Ang Lee’s film version of the strip, which unfortunately flopped, got this part of the Hulk’s characterisation absolutely right. And in the 1970s, the anti-militarist message of the strip became stronger. In one story, for example, Banner discovered and did his best to oppose dehumanising military experiments to link soldier’s brains to battle robots, experiments that had resulted in the troopers themselves feeling robotic and mechanical.

The influence of the Vietnam War in dehumanising a generation of American young men, to turn them into ruthless monsters responsible for horrific atrocities, is shown very clearly here.

And one real-life physicist, who has also come out for the Labour party is Cosmologist Dr. Stephen Hawking. Hawking told the Independent and the Mirror that he was voting Labour, because another five years of the Tories would be a disaster for the NHS, the police and other public services.

His endorsement has been welcomed by people like Dr. Alex Gates. Hawking is best known for his book, A Brief History of Time, though his background is in Black Holes. Dr Hawking even has a variety of radiation named after him. Black Holes, or rather the Event Horizons around them, are gradually evaporating, and the radiation they give off is called ‘Hawking Radiation’.

And so Dr. Gates quipped that Hawking had spotted the Black Hole in the Tories’ NHS budget.

One space scientist, who I feel would definitely have supported Jeremy Corbyn over here and Bernie Sanders in his own country, is Dr. Carl Sagan. Older readers of this blog may remember Sagan from his TV blockbuster history of science, Cosmos, and his SF novel, Contact, which was turned into a film with Jodie Foster as the astronomer heroine, who travels through a wormhole to make contact with an alien civilisation.

I very definitely don’t share Sagan’s views on religion. He was a religious sceptic and a founding member of CSICOP. But he was also a man of the Left, who hated imperialism and militarism, and supported the burgeoning Green movement. In the 1980s he warned that a nuclear war would result in a devastating global ‘nuclear winter’ of the type created by the asteroid that wiped out the dinosaurs 65 million years ago.

It’s since been shown that this wouldn’t actually occur. But Sagan was right to press for nuclear disarmament, and absolutely right to oppose the new Cold War Reagan and Maggie Thatcher were trying to whip up against the Russians.

He was also critical of the design of the space shuttle. This was supposed to be the vehicle that would open space up to just about everyone, provided you were fit enough to stand the three Gs of acceleration into orbit. The Challenger disaster put an end to that.

Sagan informed the public that the original design for the Shuttle had been for a smaller vehicle, which would have been purely civilian and much safer and more effective. However, the American military had stopped this, because they wanted a larger vehicle to carry their spy satellites. The result was the over-engineered machine, which exploded at least twice, and whose launches had to be cancelled because of engineering problems.

Sagan died of prostate cancer in the 1990s. He was a brilliant scientist and visionary, who speculated about life on Mars and Venus, and, like Hawking, was a staunch advocate of the colonisation of space. And he was inspiration to a generation of young people to have an interest in space and science. One of the most obvious examples of this is Dr Brian Cox, who freely acknowledges Sagan’s influence.

One feels that Sagan would have firmly resisted everything Bush, Blair, and now Trump, Cameron and May have done to destroy the environment and spread carnage around the world through their wars in the Middle East, quite apart from the Trump’s administration hatred of mainstream science.

You don’t have to use Sagan’s ‘spaceship of the imagination’ to travel light years to see the immense harm Theresa May and her party have inflicted on the NHS, the public services and our national security.

And you don’t have to be a great scientist to realise that the Tories’ attacks on education – their spending cuts, privatisation of schools, and burdening students with tens of thousands in debts – will stop the country’s young people fulfilling their academic potential, regardless of the bilge they may spout about encouraging the STEM subjects.

And I think Hawking has spoken out about the dangers of May’s cuts to science funding and research.

The only party that is ready to undo all of this is Labour.

So please, vote for Corbyn on June 8th.

Stephen Hawking on Why British Science Needs the EU

June 1, 2016

One of the many piece Mike put up on his site yesterday reported on Stephen Hawking’s statement that British science would be put at risk if we left the EU. Hawking was speaking as a guest on the show Good Morning Britain, and stated that the EU was good for British science for two reasons. Firstly, it allowed scientists and students from different countries to travel, thus sharing their skills, knowledge and experience. Without this exchange of personnel and ideas, Britain would be come isolated and remote from the centres of scientific endeavour. He also stated that British science benefited from generous funding from the European Union.

Another EU personality clash: Stephen Hawking vs Michael Gove. Who do YOU think should win?

Hawking’s views here are, unsurprisingly, exactly right. In fact, British intellectual culture has benefited from the exchange of staff and ideas from across the continent. Many, perhaps the majority, of unis today have teaching staff and students from elsewhere in the EU and the wider world. In the archaeology department at Bristol University four years ago, when I was studying for my postgraduate degree, there were staff from Greece, Portugal and Germany. There were also speakers at the regular postgraduate seminars from countries such as Austria and Belgium, apart from those from the other parts of the Anglophone world. These archaeologists reported on excavations they had carried out not only in their home countries, but also in places like Turkey, Egypt, Romania and the former USSR. Well some of this is no doubt possible without the umbrella of the EU, it’s made much easier with it.

And Britain does benefit from the international contacts the EU brings at a corporate and financial level. ESA, the European Space Agency, operates a system of a juste retour. Under this system, the countries that contribute the most funding to a European space project get the most contracts for it. And we’ve missed out on the benefits of closer cooperation with the European Space Agency in the past. For example, we could have been much more involved with the Ariane satellite launcher. This was developed by France from the remains of the ESRO project to build a European launch vehicle. We developed our own launcher too, Black Knight, which successfully launched a British satellite in the 1970s, but was cancelled after its first mission. We could have had a place, or many more places for our satellites, aboard Ariane. Instead, some Whitehall mandarin decided that we should instead throw in our lot with the Americans’ space shuttle. Well, we suffered there, not just because of the horrific engineering problems with that space vessel, which resulted in the deaths of the crew of the Challenger and more recent fatalities. We also suffered because the launch of our satellites depended on whether there was space left over after the Americans had filled it with the experiments they wanted for their missions. Meanwhile, Ariane, quietly and successfully, carried other countries’ experiments and satellites into orbit, while we waited for the goodwill of the Americans.

And Ariane itself, the rocket launcher, is excellent value for money. It costs the same as the Space Shuttle to launch a satellite, but that’s only because the Space Shuttle was heavily subsidised by the US government. If you’re looking for something that justifies itself according to free market ideology, then it’s probably Ariane you’d go for.

Much of the cutting-edge, gosh-wow science that science educators love, because it captures young minds, like space, atomic physics and so on, is very expensive. I doubt whether the UK on its own could bear the cost of building a particle accelerator the size of CERN, or its rivals in America. So CERN was the result of collaboration between different European nations. And the importance of international contacts and intellectual mobility between countries is also underscored by the initial post-War success of American atomic physics. The Americans were able to build such huge nuclear reactors and accelerators, not just because they had the vast financial resources to afford them, but also because they benefited from the influx of all the scientists and engineers the Nazis had chased out of Central Europe.

Mike, following one of his esteemed commenters, asks who people should believe about science and Brexit, Stephen Hawking, or Michael Gove? Really, you don’t have to have read A Brief History of Time or understand the intricacies of N-dimensional String Theory to know the answer to that one. It’s definitely going to be Hawking.