Archive for the The Universe and Stuff Category

A Decade In The Dark!

Posted in Biographical, The Universe and Stuff with tags on September 16, 2018 by telescoper

When I logged onto WordPress yesterday I received a message that it was the 10th anniversary of my registration with them as a blogger, which is when I took my first step into the blogosphere; that was way back on 15th September 2008.

I actually wrote my first post on the day I registered but unfortunately I didn’t really know what I was doing on my first day at blogging – no change there, then –  and I didn’t actually manage to figure out how to publish this earth-shattering piece. It was only after I’d written my second post that I realized that the first one wasn’t actually visible to the general public because I hadn’t pressed the right buttons, so the two appear in the wrong order in my archive. Anyway, that confusion is the reason why I usually take 16th September as this blog’s real anniversary.

I’d like to take this opportunity to send my best wishes, and to thank, everyone who reads this blog, however occasionally. According to the WordPress stats, I’ve got readers from all round the world, including  the Vatican!

If you’re interested in statistics then, as of 14.00 Irish Summer Time Today today, I have published 4,225 blog posts, not counting about 20 that I wrote but have not yet published; I’ll probably save these for my memoirs.. These posts have received 3,688,023 hits altogether; I get an average of about 1200 per day.  This varies in a very erratic fashion from day to day, but the annual average has been fairly constant over the last several years. The greatest number of hits I have received in a single day is 8,864 (at the peak of the BICEP2 controversy). Some of the most popular posts have not been about science at all, including  my rant about Virgin Media and a post about the last episode of Inspector Morse.

There have been 30,372 comments published on here and  2,213,145 rejected by my filters. The vast majority of the rejected comments were from automated spam bots, but a small number have been removed for various violations, usually for abuse of some kind. And, yes, I do get to decide what is published. It is my blog!

While I am on the subject of comments, I’ll just repeat here the policy stated on the home page of this blog:

Feel free to comment on any of the posts on this blog but comments may be moderated; anonymous comments and any considered by me to be abusive will not be accepted. I do not necessarily endorse, support, sanction, encourage, verify or agree with the opinions or statements of any information or other content in the comments on this site and do not in any way guarantee their accuracy or reliability.

It does mean a lot to me to know that there are people who find my ramblings on this `shitty wordpress blog’ interesting enough to look at, or even read, and sometimes even to come back for more, so I’d like to take this opportunity to send my best wishes to all those who follow this blog and especially those who take the trouble to comment on it in such interesting and unpredictable ways!

The last decade has been eventful, to say the least, both personally and professionally. I started blogging not long after I’d moved into my house in Pontcanna, Cardiff. Since then I moved to Sussex, and then back to Cardiff, and now to Ireland. More importantly we’ve seen the discovery of the Higgs Boson and gravitational waves, both of which resulted in Nobel Prizes, as did the studies of high-redshift supernovae. The Planck mission mission was launched, did its stuff, and came to a conclusion in this decade too. Science has moved forward, even if there are many things in this world that seem to be going backwards.

I don’t know how long I’ll keep blogging – vitae summa brevis spem nos vetat incohare longam – but I’ve got no immediate plans to stop.

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The Secret of the Universe

Posted in The Universe and Stuff with tags , , on September 14, 2018 by telescoper

 

SPIN, I spin, around, around,
  And close my eyes,
  And let the bile arise
From the sacred region of the soul’s Profound;
Then gaze upon the world; how strange! how new!         
  The earth and heaven are one,
  The horizon-line is gone,
The sky how green! the land how fair and blue!
Perplexing items fade from my large view,
And thought which vexed me with its false and true        
Is swallowed up in Intuition; this,
  This is the sole true mode
  Of reaching God,
And gaining the universal synthesis
Which makes All—One; while fools with peering eyes        
Dissect, divide, and vainly analyse.
So round, and round, and round again!
How the whole globe swells within my brain,
The stars inside my lids appear,
The murmur of the spheres I hear        
Throbbing and beating in each ear;
Right in my navel I can feel
The centre of the world’s great wheel.
Ah peace divine, bliss dear and deep,
  No stay, no stop,        
  Like any top
Whirling with swiftest speed, I sleep.
O ye devout ones round me coming,
Listen! I think that I am humming;
  No utterance of the servile mind        
With poor chop-logic rules agreeing
  Here shall ye find,
But inarticulate burr of man’s unsundered being.
Ah, could we but devise some plan,
Some patent jack by which a man        
Might hold himself ever in harmony
With the great whole, and spin perpetually,
  As all things spin
  Without, within,
As Time spins off into Eternity,        
And Space into the inane Immensity,
And the Finite into God’s Infinity,
  Spin, spin, spin, spin.

by Edward Dowden (1843-1913)

P.S. There are strict observational limits on the rotation of the Universe; see, e.g., here.

Making Better Sense of Quantum Mechanics

Posted in The Universe and Stuff with tags , , , on September 12, 2018 by telescoper

There is an interesting, pithy and polemical paper on the arXiv by David Mermin, with the abstract:

We still lack any consensus about what one is actually talking about as one uses quantum mechanics. There is a gap between the abstract terms in which the theory is couched and the phenomena the theory enables each of us to account for so well. Because it has no practical consequences for how we each use quantum mechanics to deal with physical problems, this cognitive dissonance has managed to coexist with the quantum theory from the very beginning. The absence of conceptual clarity for almost a century suggests that the problem might lie in some implicit misconceptions about the nature of scientific explanation that are deeply held by virtually all physicists, but are rarely explicitly acknowledged. I describe here such unvoiced but widely shared assumptions. Rejecting them clarifies and unifies a range of obscure remarks about quantum mechanics made almost from the beginning by some of the giants of physics, many of whom are held to be in deep disagreement. This new view of physics requires physicists to think about science in an unfamiliar way. My primary purpose is to explain the new perspective and urge that it be taken seriously. My secondary aims are to explain why this perspective differs significantly from what Bohr, Heisenberg, and Pauli had been saying from the very beginning, and why it is not solipsism, as some have maintained. To emphasize that this is a general view of science, and not just of quantum mechanics, I apply it to a long-standing puzzle in classical physics: the apparent inability of physics to give any meaning to “Now” — the present moment.

The `new perspective’ Mermin espouses is a form of `QBism (i.e. `Quantum Bayesianism’)‘. You can download the full article for free here.

Breakthrough Prize for Dame Jocelyn Bell Burnell

Posted in The Universe and Stuff with tags , , , , , on September 6, 2018 by telescoper

I awoke this morning to find my Twitter feed full of news about the award of a special Breakthrough Prize to Dame Jocelyn Bell Burnell. To quote the press release:

The Selection Committee of the Breakthrough Prize in Fundamental Physics today announced a Special Breakthrough Prize in Fundamental Physics recognizing the British astrophysicist Jocelyn Bell Burnell for her discovery of pulsars – a detection first announced in February 1968 – and her inspiring scientific leadership over the last five decades.

Bell Burnell receives the Prize “for fundamental contributions to the discovery of pulsars, and a lifetime of inspiring leadership in the scientific community.” Pulsars are a highly magnetized, rapidly spinning form of the super-dense stars known as neutron stars. Their discovery was one of the biggest surprises in the history of astronomy, transforming neutron stars from science fiction to reality in a most dramatic way. Among many later consequences, it led to several powerful tests of Einstein’s Theory of Relativity, and to a new understanding of the origin of the heavy elements in the universe.

For the full citation and background information, see here.

The prize is not only prestigious but also substantial in cash terms: $3M no less. Jocelyn has made it clear however that she intends to use the money to set up a fund to encourage greater diversity in physics, through the Institute of Physics. That is a wonderful gesture, but if you know Jocelyn at all then you will not be at all surprised by it, as she is a person of enormous integrity who has for many years demonstrated a huge commitment to the cause of increasing diversity. I look forward to hearing more about how this initiative works out.

In an interview with the Guardian, Jocelyn said “Increasing the diversity in physics could lead to all sorts of good things.” I agree, and not just because an open and inclusive environment is a good thing in itself (which it is) but also because the fewer barriers there are to entry for a particular field, the broader the pool of talent from which it can recruit.

P.S. What would you do if you won a prize of $3M?

P. P. S. If I had $3M to spend, I think I’d spend it on whatever would most annoy all the miserable twerps complaining on Twitter about what Jocelyn Bell Burnell is doing with her Breakthrough Prize money.

EDGES and Foregrounds

Posted in Astrohype, The Universe and Stuff with tags , , , on September 3, 2018 by telescoper

Earlier this year I wrote a brief post about paper by Bowman et al. from the EDGES experiment that had just come out in Nature reportining the detection of a flattened absorption profile in the sky-averaged radio spectrum, centred at a frequency of 78 megahertz, largely consistent with expectations for the 21-centimetre signal induced by early stars. It caused a lot of excitement at the time; see, e.g., here.
The key plot from the paper is this:

At the time I said that I wasn’t entirely convinced. Although the paper is very good at describing the EDGES experiment, it is far less convincing that all necessary foregrounds and systematics have been properly accounted for. There are many artefacts that could mimic the signal shown in the diagram.

I went on to say

If true, the signal is quite a lot larger than amplitude than standard models predict. That doesn’t mean that it must be wrong – I’ve never gone along with the saying `never trust an experimental result until it is confirmed by theory’ – but it’s way too early to claim that it proves that some new exotic physics is involved. The real explanation may be far more mundane.

There’s been a lot of media hype about this result – reminiscent of the BICEP bubble – and, while I agree that if it is true it is an extremely exciting result – I think it’s far too early to be certain of what it really represents. To my mind there’s a significant chance this could be a false cosmic dawn.

I gather the EDGES team is going to release its data publicly. That will be good, as independent checks of the data analysis would be very valuable.

Well, there’s a follow-up paper that I missed when it appeared on the arXiv in May the abstract of which reads:

We have re-analyzed the data in which Bowman et al. (2018) identified a feature that could be due to cosmological 21-cm line absorption in the intergalactic medium at redshift z~17. If we use exactly their procedures then we find almost identical results, but the fits imply either non-physical properties for the ionosphere or unexpected structure in the spectrum of foreground emission (or both). Furthermore we find that making reasonable changes to the analysis process, e.g., altering the description of the foregrounds or changing the range of frequencies included in the analysis, gives markedly different results for the properties of the absorption profile. We can in fact get what appears to be a satisfactory fit to the data without any absorption feature if there is a periodic feature with an amplitude of ~0.05 K present in the data. We believe that this calls into question the interpretation of these data as an unambiguous detection of the cosmological 21-cm absorption signature.

You can read the full paper here (PDF). I haven’t kept up with this particular story, so further comments/updates/references are welcome through the box below!

Sheila Tinney et al.

Posted in History, The Universe and Stuff with tags , on September 2, 2018 by telescoper

I came across the above picture via Twitter the other day. It was taken about 75 years ago, in 1943, the year that Erwin Schrödinger gave his famous lectures in Dublin on the topic What Is Life? Schrödinger is second from the right in the front row, next to Arthur Stanley Eddington (who is to his left as you look a the picture). Next but one to Eddington (to his left as you look at the picture)  is Éamon de Valera (who was Taioseach at the time; apparently he dragged all his cabinet along to Schrödinger’s lectures) and next to him (on the left as you look at the picture) is Paul Dirac. That’s quite a front row!

I’m afraid I don’t know the identity of most of the other people in the picture, apart from the lady on the far left who is Dr Sheila Tinney. She completed a PhD under the supervision of Max Born in just two years and was held in very high regard as a physicist, not least by Schrödinger himself. Sheila Tinney spent her academic career at University College Dublin and passed away in 2010 at the age of 92.

The gender balance in physics has improved a bit since 1943 but we still have a long way to go! Note also the numerous men in clerical garb.

There is a conference coming up in Dublin to mark the 75th anniversary of the What is Life lectures, and there has been quite a lot of interest in Schrödinger in the Irish media as a consequent, such as this piece in the Irish Times.

I guess most readers of this blog will know that Éamon de Valera set up the Dublin Institute for Advanced Studies (DIAS) in 1939 in order to create a position for Schrödinger, who was then basically a refugee from the Nazis. He had attempted to settle in Oxford but his unconventional domestic arrangements – he lived in the same house as his wife and his mistress – met with disapproval. Dublin was far more tolerant, and he took up the post of Director of Theoretical Physics at DIAS in 1940 and stayed in Ireland for 17 years.

If you ask me for a personal opinion about Schrödinger’s private life then I have to say two things. One is that all three members of his ménage à trois seemed quite happy with the arrangement as well as the affairs that Schrödinger had outside it. His wife also had numerous affairs, including one with physicist Hermann Weyl. Unconventional it may have been, but most conventions are pretty silly in my view.

On the other hand, there is a part of Schrödinger’s life that I do find entirely reprehensible, and that is the way he treated some of the women with whom he had affairs. As the Irish Times puts it

‘For Schrödinger, the mystical union of sexual love did not endure for long .. With Erwin it was never able to survive tidings of pregnancy.

The Schrödingers did (unofficially) adopt one of the children he fathered outside his marriage, but he strikes me as someone who wanted (or perhaps needed) the sexual and emotional fulfillment his lovers could give him, but wasn’t prepared to accept the responsibility that goes with human relationships. That strikes me as a very selfish attitude.

The Hubble Constant Tension Video!

Posted in The Universe and Stuff on August 31, 2018 by telescoper

The interwebs informed me yesterday that there’s a video out on Youtube about the Hubble Constant Tension I’ve blogged about a few times (e.g. here). The video features a number of distinguished cosmologists and Daniel Mortlock (;-). It’s well worth a look:

This also gives me the excuse to resurrect the poll I’ve been running on this issue for a few years now. Feel free to vote if you haven’t done so already…

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