Cosmology

$1.37 Million Grant for Philosophy of Cosmology

Published by Anonymous (not verified) on Tue, 08/05/2018 - 12:04am in

Christopher Smeenk, associate professor of philosophy at Western University, and James Weatherall, professor of logic and philosophy of science at the University of California, Irvine (UCI), have been awarded a $1.37 million grant from the John Templeton Foundation for their project, “New Directions in Philosophy of Cosmology.”

The grant will support work over the next three years, including a Summer Institute in philosophy of cosmology and support for graduate student research at both Western and UCI.

Here is how the principal investigators describe their project:

Physical cosmology has enjoyed decades of progress, leading to a new understanding of the cosmos and our place in it. But this success comes with new puzzles. Cosmologists seek to understand events that are far removed from us. Moreover, in many cases they study historical episodes that are apparently unique—such as the origin of the universe—and which cannot be studied experimentally. To overcome these challenges, cosmologists have often revisited basic questions concerning what constitutes an acceptable scientific theory, what sorts of explanatory demands a theory of cosmology can meet, and how to understand confirmation in this context. Their answers to these —essentially philosophical—questions have shaped the character of cosmological theory.

The principal goal of this project is to articulate and scrutinize the philosophical commitments behind cosmology’s Standard Model. With the support of a planning grant, we have conducted a landscape review of the field to identify the most significant open questions. One part of the project will present what we take to be the “philosophy of science” underlying cosmological practice, reflecting on and extending the earlier work we have reviewed. The second part of the project will dive more deeply into two pressing conceptual issues, which we identified in workshops with cosmologists supported by the planning grant: (1) the epistemological significance of the crucial role now played by simulations in linking cosmological theory with observations; and (2) the status of the large-scale structure of the universe in light of suggestions from quantum gravity that characteristic features of general relativity, such as singularities, may not persist into future theories.

In addition to this research component, the project includes outreach and capacity-building activities. It will also provide substantial training opportunities at the pre-doctoral, post-doctoral, and established researcher levels. 

You can learn more about the project here.

The post $1.37 Million Grant for Philosophy of Cosmology appeared first on Daily Nous.

Physics Textbook on Cosmology and Gravitation

Published by Anonymous (not verified) on Thu, 15/03/2018 - 10:20pm in

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.

Stephen Hawking to Play The Book in New Series of the Hitch-Hiker’s Guide to the Galaxy

Published by Anonymous (not verified) on Mon, 19/02/2018 - 5:26am in

The I newspaper yesterday reported that the physicist and cosmologist, Stephen Hawking, is set to play the Book in a new radio series of the Hitch-Hiker’s Guide to the Galaxy. Entitled ‘The Hitch-Hiker’s Guide to the Galaxy: Hexagonal Edition’ the series will commemorate the original show on Radio 4 back in 1978, featuring the original cast.

I loved the original series of the Hitch-Hiker’s Guide to the Galaxy, and the first two books based on the show, the Hitch-Hiker’s Guide to the Galaxy and The Restaurant at the End of the Universe. However, I lost interest in it after the third book. I tried reading the fourth, only to give up. I think by that time Douglas Adams himself was growing tired of writing them. I’ve heard someone say on an interview that he was only lured back to write his last Hitch-Hiker book by the publisher’s promise that in it he could destroy every possible Earth in every possible universe. So I’m not sure I’ll listen to it, especially as the series is being carried on by other writers.

I also wasn’t impressed by Adams’ expressed contempt for the genre he wrote in. Back in the 1990s he was interviewed on the radio by Paxo, who said his book was Science Fiction, but different. It was good. Adams replied by saying that he didn’t write Science Fiction. Which is odd, because that’s what Hitch-Hiker is. But I guess Adams wanted to avoid being pigeonholed as a genre writer.

At that time the prejudice of the literary establishment towards Science Fiction and Fantasy was much stronger than it is now. I can remember seeing Terry Pratchett speaking at the Cheltenham Festival of Literature, saying how the organisers looked on him as if he was going to talk to people about fixing motorcycles. There’s a clip of the BBC arts programme, The Late Review, in which the Oxford lecturer and poet, Tom Paulin, and a female litterateur are asked to review one of Pratchett’s books, where they both make very disparaging remarks. The woman states that she felt like writing across it in big lines ‘I cannot read any more’. Paulin compared it to lifting up a stone to find all these weird people doing weird things underneath it. And going further back to the 1950s Brian Aldiss commented in The Trillion Year Spree that at that time, despite being championed by Kingsley Amis, pornography had a better reputation than Science Fiction amongst the literary elite.

Pratchett had to fight against that literary snobbishness throughout his life, but is now being taken very seriously by critics. I think Adams avoided it. Back in the ’90s he and Hitch-Hiker were the subjects of one edition of the South Bank Show with Melvin Bragg. But perhaps the price of that critical acclaim was his denial that he wrote Science Fiction at all.

But other people are different, and so I’ve no doubt that there are millions of Hitch-Hiker fans out there, who will be delighted to hear the news. They know who they are. They’re the people, who bought merchandising, like the Hitch-Hiker bath towels. This was a large, white bath towel with the text from the HHGG talking about how every Hitch-Hiker really needed to know where their towel was on it. I found one of those in Forever People, the comics/ SF shop in Bristol. The show’s fans are also the people, who organised conventions with dubious names like ‘Slartibartday’, after one of the creators of the Earth, Slartibartfast.

Hawking is in many ways an ideal choice for The Book after the death of Peter Jones, who was its original voice on Radio 4 and then in the BBC 2 TV series. He already has an electronic voice to fit the character of an electronic book, and is a world famous space scientist and advocate of space colonisation. But you wonder how massive his ego will be after playing a publication, which the Hitch-Hiker’s Guide to the Galaxy describes as, amongst some people, having displaced the great Encyclopaedia Galactica as the standard repository of all knowledge and wisdom.