Plus Blog

June 17, 2009
Wednesday, June 17, 2009

In our second online poll to find out what Plus readers would most like to know about the Universe, you told us that you'd like to know if the constants of nature really are constant. We took the question to cosmologist John D. Barrow, Professor of Mathematical Sciences at the University of Cambridge, and here is his answer. Please feel free to discuss the answer by leaving a comment on this blog. We'll periodically check back with the experts to try and answer interesting further questions.

This article is part of a series to celebrate the International Year of Astronomy 2009. The third poll to find out what you'd like to know most about the Universe is open now, so get voting!


posted by Plus @ 1:15 PM


At 2:36 PM, Blogger Shelly said...

The speed of light is assumed to be constant. Einstein, Hawkings and many, many other scientists of great renown have assumed this.

Why? Is there any theoretical proof?

At 4:50 AM, Blogger Seeley said...


At 9:42 AM, Anonymous The Plus Team said...

This post has been removed by a blog administrator.

At 9:49 AM, Anonymous The Plus Team said...

Hi Shelly,

We took your question about the speed of light to John D Barrow and here is his answer:

"No, there can never be a proof that the speed of light is constant. Relativity theory requires the speed of light in vacuum to be constant and the same for all observers. All we can do is test whether that is true and hence whether the theory of relativity is a corrrect description of nature. There may be tiny quantum mechanical corrections to the theory which produce very small changes in extreme environments (very small distance, high frequencies or strong gavitational fields)."

We hope this answers the question!

At 12:03 PM, Blogger Martijn said...

"An added subtlety is that in most of these possible worlds life cannot exist."

This leads to another question: what do you mean by 'life'? What makes life special? How can it be that there might be a world where rocks etc. can exist but 'life' (whatever definition you choose for that word) can't?

At 1:55 AM, Anonymous dheeraj said...

A constant is nothing but it is a derived numerical ratio between the two same fundamental quantities.The constant is said to be a point function,since it is constant at a point when it is made to travel at different atmosphere with different velocities,the value of constant may varie and moreover an example to say that the velocity of light is constant,when abody is made to move with a velocity equal to light then the constant may vary relative to this object constant is an induvidual point function and independent from the different variables.

June 17, 2009
Wednesday, June 17, 2009

This special double issue of Plus is cause for celebration: both of the endeavours of physics to understand our Universe, and of the writers of tomorrow who may help explain it. We explore the frontiers of modern physics: searching for alien life in space and exotic particles in the LHC, looking through the Hubble Space Telescope, imagining a holographic Universe, and wrestling with one of the biggest problems in modern physics. And the winners of the Plus new writers award 2009 explore the most beautiful equation of them all, explain the credit crunch, and unveil the curse of good looks. We raise a toast to mathematics and physics — to all the explorers of the new frontiers and the new writers who can take us there!

Read issue 51 of Plus!

posted by Plus @ 1:26 PM


June 17, 2009
Wednesday, June 17, 2009

What would you like to know about your Universe — The third online poll

This poll is now closed. The most popular question was: "What are dark energy and dark matter?" We will publish the answer in an article and podcast on Plus shortly. Thank you for taking part!

This is our third online poll in our series to celebrate the International Year of Astronomy 2009. Choose your favourite question from the list on the right, and we'll put the one that proves most popular to world-leading astronomers and cosmologists, including Astronomer Royal Martin Rees and author and cosmologist John D. Barrow. The poll will remain open for a month and the answer will be published in a Plus article and podcast soon after. If your most burning question is not on this list, then leave a comment on this blog and we'll endeavour to include it in a future poll — there will be four more polls dotted throughout the year.

The most popular questions in polls far were was What happened before the Big Bang? and Are the constants of nature really constant?. Read the answers by clicking on the links, and discuss them on our blog.


posted by Plus @ 3:33 PM


At 8:32 AM, Blogger idkk said...

Dark matter is possibly "easy" to determine: neutrinos have mass. That simple (but hugely ignored) fact could provide both sufficient mass and energy to explain the otherwise unobserved masses and energies that puzzle us.

But how Gravity works - well, that's something I would really like to know.

June 4, 2009
Thursday, June 04, 2009

Not so fantasy football

Next time you're off to the bookies to place your footie bets, you might be better off consulting a statistician than a football expert. On his Understanding Uncertainty website self-confessed football un-enthusiast David Spiegelhalter used a simple statistical model to predict the results of the last ten Premier League matches, which were played on the 24th of May 2009. In terms of predicting whether a game ended in a win, draw, or defeat for the home team, Spiegelhalter's model was right nine out of ten times, compared to the seven out of ten score achieved by the official BBC football expert Marc Lawrenson, and the model predicted two scores exactly.

Spiegelhalter and his co-authors Mike Pearson and Ian Short quantified the individual teams' attack strength and defense weakness based on their past performance, and then, with a little help from probability theory, used these ratings to work out the most likely outcome of a particular match. (You can see the details of this model on his website.) "These types of models have been refined over the years and are now used by bookies and sports betting companies, who employ experienced statisticians and make use of the latest computational methods," says Spiegelhalter. But he concedes that his very basic model might have been a bit lucky this time: "One thing you can bet on is that simple models like this one will be very unlikely to out-perform the odds being offered by bookies, so don't use them to spot good bets!"

Spiegelhalter announced his prediction on the BBC Radio 4 programme More or Less, which was aired before the final match day, so you can be sure that no hindsight fraud was involved.

David Spiegelhalter is Winton Professor for the Public Understanding of Risk at the University of Cambridge and regularly writes for Plus (see for example his article on the 2006-2007 Premier League season). His Understanding Uncertainty website is designed to inform the public about everything to do with risk and uncertainty, from health scares to predicting election results.

posted by Plus @ 8:05 AM


At 9:42 AM, Anonymous sports picks said...

davids approach seems quite nice to me, so i think it takes into account all the strength and weakensses of both the teams, now leaving the thrill factor (which is still very much alive,as it is a guide only) i think if one is thinking of investing in sports picks ,the theory appears nice in principle,
cheers, richard,

June 2, 2009
Tuesday, June 02, 2009

At the very heart of sport is a fierce battle in which the combatants strive to outwit and outplay each other. Each thrust is matched by a parry and in the end, there can only be one winner. The rules of each sport dictate how that winner is determined, and whether it is football, tennis, golf or chess, it is those who perform best on the day who take home the glory. This latest installment of the Plus sports page looks at two ranking systems that couldn't be any different from each other — those of sumo and chess.


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posted by Plus @ 2:31 PM


At 6:35 AM, Anonymous Ken said...

Nice work guys. Plenty of stimulating material for my maths students here.I'm a secondary school maths teacher with a keen interest in mathematical modeling. Looking forward to future articles.

May 26, 2009
Tuesday, May 26, 2009

Take a trip through the looking glass...

Looking for something to think about next time you gaze at your reflection when brushing your teeth? Then Sara Santos has some mathematical inspiration for your next daydream in her MMP public lecture, Through the looking glass... again and again!. If Alice took a magic trip inside a conic arrangement of mirrors, what would she find in this mathematical wonderland? You can take a look through a 3D kaleidoscope to see what happens to Alice's cubes and icosahedrons!

Sara Santos is Clothworkers' Fellow in mathematics at The Royal Institution of Great Britain (Ri) and is responsible for coordinating the UK-wide network of secondary Ri mathematics masterclasses. Sara will be speaking at 11am on Thursday 11 June 2009, at the Centre for Mathematical Sciences, Cambridge, just down the hall from Plus! Admission to the lecture is free but by ticket only — for tickets please contact Kerstin Enright, Millennium Mathematics Project, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA (01223 766839) or email: You can also sign up for notifications of future MMP events at the MMP site.

And don't forget you can also see the London Mathematical Society's popular lectures on Monday 22 June in London and Tuesday 15 September in Birmingham. Come and see how physicists helped answer a hundred year old question about prime numbers and how random matrices and Riemann zeroes feature in a major Hollywood movie with Nina Smith. And Mark Miodownik will explain how fleas can jump over 100 times their own height, flies can walk on water and a hamster can survive falling from aircraft without a parachute.

Admission is free, but by ticket only. For more information and tickets, contact Lee-Anne Parker, London Mathematical Society, De Morgan House, 57-58 Russell Square, London,WC1B 4HS (email:, or visit the LMS website.

But if you can't wait til then, you can take a trip through the looking glass and discover the importance of scale to weightlifters and kitten on Plus!

posted by Plus @ 12:43 PM


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