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By Tushna Commissariat
The results of a successful scientific experiment can make scientists very happy. Indeed, in the clip above, taken from the BBC TV series Human Universe, one scientist exclaims “holy mackarel!” when he sees the outcome he was hoping for. In the video, everybody’s favourite physicist Brian Cox carries out an experiment similar to Galileo’s Leaning Tower of Pisa experiment, where he tested that no matter the mass of objects, they fall at the same rate under gravity. In the video above, Cox drops a bunch of feathers and a bowling ball in the world’s biggest vacuum chamber – the Space Simulation Vacuum Chamber at NASA’s Space Power Facility in Ohio, US. In the slow-motion video, you can see with exquisite clarity just how accurate Galileo’s prediction was, as the feathers and ball land at precisely the same time. We came across this video on the Dot Physics blog on the Wired Science network, written by physicist Rhett Allain, where he has worked out some of the maths and pointed out some of the nuances of the above experiment, so make sure you take a look.
Our regular readers will have seen that yesterday I pointed you to a live webcast of “Quantum Mechanics and Spacetime in the 21st Century” – a lecture by physicist Nima Arkani-Hamed as part of the Perimeter Institute’s Public Lecture Series. You can now watch the lecture on YouTube. Also, take a look at physicist Peter Woit’s blog Not Even Wrong, where he has a slightly more critical take on the lecture and Arkani-Hamed’s views on supersymmetry. Don’t forget to tell us in the comments below which camp you fall into!
Also, to commemorate what would have been much-loved physicist and science communicator Carl Sagan’s 80th birthday, the Perimeter Institute has put together a very fun list titled “19 awesome things about Carl Sagan other than Cosmos“. Do take a look to find out how long a Sagan Unit is and what a mysterious “Mr X” wrote about in an essay in 1971.
The Internet is abuzz with talk about the latest physics-related blockbuster film Interstellar, which is out today. As I am reviewing the film for Physics World, I have been careful to not read any reviews about the film just yet! But I have it on good authority from colleagues that this blog by physicist John Preskill titled “When I met with Steven Spielberg to talk about Interstellar” and this interview in Science magazine with Kip Thorne, titled “Physicist who inspired Interstellar spills the backstory – and the scene that makes him cringe” make for some excellent reading. Next week, I will also be attending a première of the film Theory of Everything, which encapsulates the early life of celebrated physicist Stephen Hawking. I am quite looking forward to the “red carpet, Leicester Square” event, and I will be writing about the film soon after, so keep an eye out for it on the blog next week.
And finally, see if you could land a vehicle on a comet, as the Rosetta craft will do next week, thanks to this interactive game on the BBC website and take a look at some pictures from the life of a PhD student on the Guardian website…my favourite is “Space Desk”.
Not to argue that Brian Cox’s gee whiz, aw shucks school of ain’t physics neat isn’t useful, but it often misses a most of the important subtleties. While Galileo certainly made the right abstraction re. the progress that resulted (i.e. to a vacuum), Aristotle, often portrayed as the anti-Galileo and enemy of progress, was also correct but via a very different abstraction, i.e. gravitational motion in a medium for which objects instantly reach terminal velocity. In that case objects fall with a constant velocity proportional to their weight (terminal velocity) and he even did the right experiment to test that, i.e. dropping things in water. Who knows, maybe there will be some subtle Aristotelian type effect for objects traveling through the Higgs field or the vacuum…
I’m with Woit as regards Nima Arkani-Hamed. He’s painted as some kind of guru, but he doesn’t know there’s a photon-photon interaction or that in some respects the virtual photon is a virtual graviton, he thinks of gravitons as real particles, he thinks gravity gets strong at short distance, he doesn’t understand spin or the electron, he doesn’t know that a massive particle is like a massless particle in a closed path, he doesn’t know that mass varies with gravitational potential, that spacetime is an abstract thing that is not space, that gravity is to do with inhomogeneous space rather than curved space, or why gravity is so weak. And and oh boy, what a load of old tosh about the smaller and smaller box and the macroscopic universe. It’s obvious he doesn’t understand general relativity and that his cosmology is weak, but there he is peddling string theory and extra dimensions and supersymmetric tosh, and just getting in the way of scientific progress whilst physics continues to wither on the vine. Talk about vacuum catastrophe. Rah rah, talk about [i]Emperor’s New Clothes[/i].
Nima Arkani-Hamed’s claim that time and space may be emerging entities and by implication, also all the laws of Nature, is going to be tough to show and test, but overloading him with one’s often repeated diversionary load makes the things even messier.
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