The Davies Sphere

I read this article on io9 about artificial gravity and was reminded of the famous 'Dyson Sphere' idea dreamed up by Freeman Dyson. The article describes the concept of building a spherical space station around an artificial (very small) black hole such that the gravitation force on the station would equal the gravitational force we feel here on Earth. Cool idea, and in some ways similar to a Dyson Sphere, except that people live on the inside of a Dyson Sphere, rather than the outside of the black hole space station. We're also talking about massively different structures in terms of scale.

So what about a combination of the two ideas? A sphere built around the Sun with a radius such that the Sun provides a gravitational force on the sphere surface that equals Earth's, so that people could live on the outside? Gravity in a normal Dyson Sphere is an open question, it doesn't provide any gravity for people to use to live on the inside surface, so it's a problem to be solved. Not so with my sphere as the Sun provides the gravity. But how big would a 'Davies Sphere' (and I hereby claim eternal dibs on the idea by naming it so ;) ) have to be for the gravity on it's external surface to be equal to Earth's?

Well, I've studied a little bit of physics and so I *think* I can work it out*. The force of gravity on the surface of the Earth is roughly 9.81ms^-2, and the equation required to work that out is this:

g = GM/R^2

where G is Newton's gravitational constant, M is the mass of the Earth and R is the radius of the Earth. I want to rearrange the equation to find R (the radius of a sphere basically) by using the mass of the Sun and keeping the same value for g:

R^2 = GM/g

R^2 = (6.67x10^-11 Nm^2kg^-2) x (1.99 x 10^30kg) / 9.81ms^-2

Work that out and you get a value for R of 3.68x10^9m. Now, that's the radius of the sphere built around the Sun that would have Earth like gravity on it's surface. But that's measured from the centre of the Sun, so I need to subtract the radius of the Sun itself to get the distance between the two:

3.68x10^9m - 6.96x10^8m = 3 x 10^9m to one s.f. - in other words the sphere's surface would be about 3 billion metres, or 3 million km from the Sun. Sounds a long way, but the orbit of Mercury at it's closest to the Sun is 46 million km! So the Davies Sphere would be reeeeeaaaallly close to the Sun! I expect it would have to be made from some new super light-weight, super heat-resistant material, but hey that's not my problem, future engineers can figure the easy bit out ;)

Other thoughts about the Davies Sphere - in contrast to the Dyson Sphere, no one will be living on the inside, so the entire inside can be coated in solar energy collectors to capture the entire EM energy output of the Sun. Apart from a few 'windows', aligned with a set of massive orbiting mirrors which, when the 'windows' in the sphere allow sunlight through, reflect it back over the outside surface of the sphere. So, if opened simultaneously, the entire surface of the sphere could have a simultaneous day/night cycle.

The surface area of the Davies Sphere works out to be 1.13x10^20m^2, which is nine orders of magnitude more than the surface of the Earth - so room to move wouldn't be a problem at all! So there it is, my idea for the future of humanity - no thanks required ;)

I should really get back to work now :)

*this may well all be totally and utterly wrong. Really quite likely.

Christopher Hitchens for The Skeptic Magazine

This started out as just a piece for myself, I'd seen some really wonderful portraits recently (many of Steve Jobs who also died recently) and so I wanted to do something along similar lines for Christopher Hitchens who died last December. I sent an earlier version to The Skeptic Magazine to see if they might want to use it if they were doing a piece on Hitch any time, and they thought it good enough to be the next cover. It needed a fair amount of work (in fact it probably still does if I'm honest), mainly to fit the magazine cover layout, but now I'm pretty pleased with how it looks :) If anyone would like an A3 print of the painting I'll make them to order for £15.00 inc p&p, so just send me an e-mail if you'd like to get a copy.

The new copy of the magazine also comes with a poster of Crispian Jago's amazing Modern Science Map!

Skeptic magazine cover - John Ronson

This illustration was FUN.

The team from The Skeptic Magazine told me they wanted Jon Ronson on the cover and that his new book The Psychopath Test was just out (it's a really good book, grab it if you can). This idea came straight away an I did a sketch, thinking that they'd think it was a bit 'out there' and I'd have to tone it down or come up with something else. Nope - they liked it and so I went for it!

The idea is pretty simple, Jon is in a school classroom having just taken a 'psychopath test' and the teacher is handing him back his score sheet with a 100% mark. The slightly mad bit is that he's dressed AND made up as The Joker from The Dark Knight - it was a bit of a challenge to caricature someone and then give them full face make up of someone totally different. I was worried the likeness would vanish under the white make up and red lipstick. I think it came out ok though. There are lots of other little things in it too which I really enjoyed putting in. Can't wait to do the next one if they still want me!

BBC Science Rocks!

This design idea arose when I was trying to think of something to pay my own small tribute to the great science programmes being put out by the BBC. Series after series of amazing stuff; Frozen Planet, Wonders of the Universe, Cell, The Story of Electricity, The Human Body, Are We Still Evolving?, The Story of Maths and of course The Sky At Night (and that's just to name a few). There are many other BBC science presenters I couldn't fit it also. You can buy the t-shirt here. Let's go to work ;)

Galileo 'SCOPE t-shirt design

Thought this was a bit of fun - another geek t-shirt to add to the list! Galileo 'SCOPE t-shirt

New t-shirt design 'Four Horsemen 2012'

Available to buy right here: Four Horsemen 2012

Philip Stein watches and Christopher Hitchens

Like many other people may have done, I spent a fair amount of time last Friday reading tributes and listening to the words of Christopher Hitchens after learning of his death. There are so many of his debates on YouTube, you can easily spend hours enjoying his uncompromising style of argument in his distinctive voice. A personal favourite speech of mine is this remarkable one he gave on free speech for example. I also watched a debate I hadn't seen before; this one with Rabbi Shmuley Boteach (it is a pretty terrible recording though).

I'd seen Hitch debate with Boteach a couple of times before, and this one seemed a little more friendly and less combative than others. Even so, Hitch is forced at one point to deliver what I am contractually obliged to call a Hitch-slap to Boteach when the Rabbi attempts to blame Hitler and the Nazi's on atheism (around 50 mins into the video). We've all heard that one before of course, but I was amused a couple of days later to read in Daniel Dennett's tribute piece to Hitch: A lesson from Hitch: When rudeness is called for of an earlier occasion of Hitch performing a similar rebuke to the same Rabbi, this time on the very similar and just as wrong claim that Hitler was inspired by Darwin. I don't know if on that occasion Boteach conceded the point, but he did in the video above. It will be interesting to see if he uses the argument in debate again.

To get to the point though: at the end of the debate, Boteach presents Hitch with a Philip Stein watch which was apparently a special watch made for a family-oriented campaign the Rabbi is involved with (and he asks Hitch to also become a patron). I like looking at watches and so I looked up Philip Stein to see what their watches were like (they are beautiful), there are some on Amazon and if I were not cursed with stupid skinny girl wrists and lack a spare £1000+ I would love to get one. So then I went to Philip Stein's website to see what else they had. Unfortunately the catalogue section seems to be broken so I couldn't browse the range, but I did then click on the Frequency Technology section to see what that was all about.

As a skeptic, this section has many claims that sound very familiar, especially if you know about things such as magnetic healing bracelets, Power Balance bands etc and it also has bits reminiscent of Qi, acupuncture etc. For example:

Natural Frequency Technology in Philip Stein watches is based on key frequencies beneficial to life and health, which are embedded on a metal disk found in every Philip Stein watch.

Initially though, it claims to have scientific legitimacy because of a published paper. I haven't read that, nor do I have the scientific credentials to give an opinion (there are plenty of skeptics out there who do of course) but I am certainly very skeptical of the claims being made on that page as they sound very much like nonsense woo-woo I've seen from many other products. Interesting that a high-end (I assume) watch maker would choose to use such techniques to sell four-figure value watches.

What really did irk me though was looking at the Who Wears It section, and finding a photograph of Christopher Hitchens and Shmuley Boteach, obviously taken at the debate described above. Whether or not Hitch agreed to his photo being used to promote the watch brand I do not know, but I doubt very much he would have done so if he were aware of the highly unscientific nature of the claims being made to sell the watches. Oprah Winfrey appears twice on the same page, which probably tells you all you need to know.