Not so fundamental anymore, now are ya?
July 31st, 2009
So apparently the electron is not indivisible after all. Except, this is actually old news? What exactly is going on here?
Archive
Posts Tagged ‘Science!’
Who says computer scientists don’t know how to have fun?
July 30th, 2009
Who says computer scientists don’t know how to have fun? As a counterexample, consider a new post over at Gödel’s Lost Letter that was obviously the result of some Wednesday-night festivities and intoxication.
I think, in a sense, we are the accelerators. As we smash ideas together sometimes we discover the further structure of our fundamental particles—our complexity classes.
Duuuuude.
Downtown, Γαλαξίας
January 5th, 2009
For anyone that needs a new wallpaper, here’s a breathtaking photograph peering into the center of our galaxy, thanks to telescopes Hubble and Spitzer:
More information is available here, or click on the picture itself for links to larger versions, including a 6000-pixel wide JPEG.
The amount of detail in the high-resolution version is absolutely amazing, but nearly insignificant in context: the picture captures an area 300 light years wide, or more than 3000 AU per pixel. Given that our solar system is roughly 80 AU in diameter, each pixel reveals a square of space 40 times wider than our own solar system.
We share an amazing universe.
The original mythbuster
January 5th, 2009
Seven years after the fact, it’s slightly surreal to read post-9/11 responses again. Time makes it easy to forget that everyone in the world had hysteria-inducing levels of adrenaline flowing through their blood for at least a month after the attacks, enough to make even the brightest people believe the proper response to be for the highest civilisation ever to invade all the Arabs and convert them to our way of life. (Surely this seemed tractable at the time.)
Meanwhile, there’s this article over at BBC News about (ahem) Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Haytham, a tragically poorly-known, 10th-century scientist whose name the West (for reasons I cannot understand) abbreviated Alhacen. To name only a few of his discoveries, he
- Invented the scientific method, and stressed the importance of demonstration by experiment rather than philosophical argument,
- Showed that incandescent objects radiate light outward in straight lines,
- Discovered various properties of refraction and reflection,
- Argued that the speed of light is very great but finite,
- Invented and explained how the pinhole camera works,
- Learned how to integrate polynomials 700 years before Newton did, and
- Very nearly discovered non-Euclidean geometry.
We may in fact be the highest civilisation ever, but sometimes it’s a good idea to remember which of its parts we borrowed, and how they sprang from such lesser parts of the world.
The universe is a fractal
January 2nd, 2009
Einstein famously wrote that “the most incomprehensible thing about the world is that it is comprehensible.” By this benchmark, one of the most amazing properties of our universe is the amount of self-similarity it contains, how the same phenomena occur on various scales of size, time, and in various forms of matter and non-matter. The laws of Nature seem designed to allow complex behaviour to be approximated by fundamental laws that appear also on smaller scales.
Mechanical waves (of water, sound, and so on), which are incredibly complex systems made up of a billion billion billion molecules, each made up of atoms made up of electrons and protons and neutrons made up of quarks, propagate in a fashion remarkably similar to the way individual photons do in an electromagnetic wave.
Even the familiar formula for a photon’s momentum, p = E/c readily approximates the momentum that a mechanical wave carries, when we substitute the wave’s velocity v for the speed of light c.
The waves of water in a pool interfere exactly like electromagnetic radiation does, but by entirely different processes! Photons interfere even when there is only one photon according to the laws of quantum mechanics. Comparatively, mechanical waves propagate and interfere for classical reasons, by the momentum carried from atom to atom in an unimaginably long chain, in order to mimic the behaviour of electromagnetic waves.
The gravitational force exerted by a planet 12,000 kilometers wide made up again of an enormous number of particles is approximately that exerted by a single point of the same total mass. And it is exactly into this shape that gravity tends to mold the matter in the universe, as if to make its effects as simple to analyze.
Combining the above two observations, we may analyze the mechanics of one billiard ball striking another by applying a much simpler model than the one seemingly required by reality.
This kind of approximately self-similar behaviour in Nature brings Microsoft’s Photosynth technology to mind. At an incredibly zoomed-out perspective, complex interactions average out and allow the billiard ball to be seen as a lone object, striking another ball and instantly transferring its kinetic energy into it. Only as we zoom in do we begin to see the detailed interactions inside the balls, and how the kinetic energy is transferred between them by means of a wave propagating through their matter. Zooming in further we see the balls’ individual atoms wiggling about and interacting, the cause of what previously appeared to be a wave.
If mankind one day decides to engineer an efficient universe, our own seems like a good model.