Physicist: No…
But to be fair, when a physical law is beaten it stops being a law.
Archive for the ‘Paranoia’ Category
Q: Is it possible to beat the laws of physics?
Monday, July 26th, 2010Q: How/when will the world end?
Monday, April 26th, 2010Physicist: To answer this question definitively would require the destruction of at least a couple dozen other worlds. But failing that, guesswork:
The little things (people): In the short term (less than several million years) the biggest threat the Earth faces is people. We’ve already got the Holocene mass extinction going for us, now we’ve just got to step up our game and go for broke. Hey, Coalition of the Willing! I think I saw North Korea stealing your cup cakes. Also, it’s too cold in the winter. Couldn’t we burn a teraton of coal or something?
Boring, Regular Extinction: It we (Homo sapiens) follow the same fate as all of our predecessors and cousins (homo habilis, rudolfensis, georgicus, ergaster, erectus, cepranensis, antecessor, heidelbergensis, rhodesiensis, and neanderthalensis, for example), then it’s very likely that we’ll be extinct within the next 100,000 to 1,000,000 years. Statistically speaking anyway.
Total carbon re uptake: Over very large time scales the sun is getting brighter (along the lines of about 10% per billion years). Astrophysicist Brownlee and paleontologist Peter Ward have written a book espousing the idea that this gradual brightening will cause the Earth to heat up and the natural chemical processes that absorb CO2 from the air (and lock it away in sediment) will speed up.
"Main sequence stars", which include the sun, are surprisingly stable for a very long time. They do change a little, increasing their brightness by about 10% every billion years.
They figure that inside of 500 million years there won’t be enough CO2 in the atmosphere to support plant life, and that would be the end of complex life. Although life has been around for at least 3.5 billion years, the interesting stuff (animals) have only been around for about 500 million years. So if Brownlee and Ward are right, we’re only about halfway done (not nearing the end).
It may seem strange to talk about the loss of CO2 being the end of the world when we so often talk about the dangers of too much CO2. The difference is in the time scales. The spike of CO2 we worry about today is on the scale of centuries, while the long term absorption of CO2 is on a time scale a million times larger (unnoticeable in the short term).
Dynamo shutdown: The Earth’s magnetic field is the result of iron rich (electrically conductive) stuff flowing around in the Earth’s core. The currents are driven by radioactive heating which causes convection, specifically the decay of radioactive potassium, uranium, and thorium. The half-lives of these materials are 1.25 billion, 4.5 billion, and 14 billion years respectively, so most of the original fuel has already been used up.
The exact nature of magnetic dynamos is not terribly well known, and is still an active area or research. We don’t know for certain what the minimum energy input is needed to keep the damn thing running. We do know that it’s certainly possible for a planetary magnetic dynamo to shut down (Mars’ shut down at least a couple billion years ago). If our dynamo shuts down, then our magnetic field will vanish and (in fairly short order) the atmosphere will be stripped away by solar wind, as happened on Mars.
Never-ending Summer: The increase in the Sun’s output will make it too hot for liquid water on Earth in about 1 billion years. With the oceans boiled away the pressure everywhere on Earth will be about the same as the pressure on the ocean floor. The difference between Venus and Earth will be academic. No matter what else happens before then, this will be the end of life on Earth.
SPF 5,000,000,000,000,000: Somewhere around 5 to 7 billion years from now the Sun will start to run out of fuel. Ironically this will actually make the core hotter as it collapses in on itself. The top layers will fluff up and (probably) envelope all the inner planets, including Earth. For obvious reasons this is called the “red giant” phase of the Sun’s life. The solar system will eventually settle down with the gas giants still in place, the inner solar system missing, a white dwarf star where the Sun used to be, and the trans-neptunian stuff completely unaffected.
The Sun as we see it today (yellow), and the Sun in its fluffier red giant phase (red).
Lights out: If by “end of the world” you mean “end of the universe”, then a good end of everything is the end of the age of stars. The universe started out made up of about 75% hydrogen, but today is only about 70% hydrogen. Stars are almost completely powered by hydrogen fusion, so assuming that the consumption of the universe’s hydrogen is stays constant (which isn’t a particularly good assumption), then there will be almost no stars left in 250 to 300 billion years.
The big rip: Not only is the universe expanding, but the speed of that expansion is increasing. The expansion is a little hard to picture because the expansion isn’t about things moving away from each other in space, it about the space in between things actually expanding. Right now the effect is small enough that it can only be seen on huge, inter-galactic, scales. But eventually the expansion with be so rapid that the space between the planets and their stars will increase so fast that the planets will be pulled into open space, and not long after than (as in a couple of months or so) the space between atoms will increase so fast that everything will be completely torn apart and atomized. This is called the “big rip”. Some estimates put the big rip about 20 billion years out, and some say it won’t happen at all.
Q: Is it of any coincidence that mathematics is able to describe physical reality – given that both are inventions of the human mind?
Friday, March 5th, 2010Physicist: There’s a lot of math that doesn’t describe physical reality at all, and even some (few) mathematicians who feel that
“applicability” is just another word for “impurity”. The ability of math to describe reality is just a consequence of the fact that reality is nice and consistent.
The fact that the math we use (addition, subtraction, geometry, calculus, whathaveyou) works is no coincidence at all. Mathematics literally evolves in the sense that, if something doesn’t work, then people will ignore it. So if you have a theory that 
π=7
However, just because something works in your head has absolutely no bearing on whether or not it will work in reality (which you would expect if the physical world were created by our minds). Very good, very reasonable ideas get shot down by experiment every day, and we are constantly surprised.
Philosopher: If we assume the external world exists (independent of our minds), Math’s correspondence to reality is no more coincidental than the correspondence to reality of theories stated in any other language. This isn’t dependent on the existence of mathematical objects, and it’s not dependent on Mathematical truths existing independently of humans (though I think they do). If we assume the external world is merely an “invention of the human mind”, then the correspondence of Math to the world is even less coincidental, since the same thing is the author of both.
Q: Do we have free will?
Saturday, February 27th, 2010Physicist: If you want to get into an argument that drags on forever, you can frame a question like this in terms of consciousness, and the nature of choice, or any number of other ill-defined ill-understood ideas. So consider only the question in terms of determinism;
Q: “does the state of the universe now (and in the past) completely determine the future of the universe and, by inclusion, the future of me?”
Back in the day (classical physics day) the answer could rightly be “yes” or “I don’t know”. However, with the advent of modern quantum mech we’ve managed to make great strides on questions like this. Now we can answer: “yes, no, and kinda”! It’s progress like this that almost makes going back to clipper ships and horse carts worth it.
One of the biggest weirdnesses to come out of quantum mechanics is the idea of “super-position”, which is that a single thing (a particle or whatever) can be in multiple states at the same time (the state of a thing can involve position, speed, orientation, and even how the thing is related to other things). QM allows us to see how all of those states change in time and interact each other. However, any direct interaction with an “undetermined state” will reveal it to be in only one (of its many) state(s). In what follows I’ll use “universe” to mean the universe with just one state (things did happen this way), and multiverse to mean all the states involved simultaneously (with all the interference and what-have-you).
The two ways of looking at this are the “Copenhagen interpretation” (wrong) and the “many worlds interpretation” (right).
“Yes!”: Given complete knowledge of the multiverse’s quantum wave function you can determine the future of that function forever. Unfortunately, this isn’t particularly useful for those of us who live inside the universe. The wave function in question encompasses all possibilities simultaneously and involves plenty of self-interference. For example: when you do the double slit experiment you can calculate exactly what the fringes will look like on the screen, by doing a calculation that assumes that the photons involved go through both slits. However, if you were to instead look a one of the slits, this doesn’t tell you anything about whether or not you will see the photon go through that slit.
(Just a quick note about the link above. “The Secret”, and its creepy brainchild “What the bleep”, are both symptoms of a greater douchiness, but despite their culty bent they explain the double slit pretty well.)
In fact what happens is it goes through both slits, but in turn there are different versions of you that see both outcomes. If you look at the multiverse as a whole (seeing every state) then everything is completely deterministic. If you look at just one tiny piece at a time (like we seem to), then everything seems random.
Essentially, for every choice you can make, there are a whole mess of versions of you (identical up to the moment of choice) that do make that choice. In fact, if your wave function is known completely, then how much (many?) of you goes down any road can be derived. I don’t want to hear anyone saying “but I chose to do that!”, because some (part?) of you had to. But then, some of you had to do every available choice.
“No!”: Part of the Copenhagen interpretation is fundamental, true randomness. There’s no multiverse in Copenhagen (so don’t go flying there to look), so any choice you make is unpredictable (or at least, not completely predictable, there are some pretty reliable people out there) in the sense that no matter how good your fore-knowledge of someone’s wave function, you still can’t make perfect predictions.
It’s seems like there’s enough wiggle room in there to fit some free will.
“Kinda!”: Even if you subscribe to the many world hypothesis you could argue that “dude, who cares?”. You’ll never meet (can’t meet) those other versions of yourself, so what does it matter that, in theory, all of your simultaneous actions are determined in a multiverse-kind-of-way? Doesn’t.
Q: Is there a formula for how much water will splash, most importantly how high, and in what direction from the toilet bowl when you *ehem* take a dump in it ?
Thursday, February 4th, 2010Physicist: If it weren’t for imponderables like this, we’d have finished science years ago. During an “impact event” water generally moves outward to the sides. What you really need to worry about is the dreaded “water spike”.
- Ejecta, spike, ejecta, and spike. (The artwork in the upper-left is by Chrstara, Copyrighted © http://abstract.desktopnexus.com/wallpaper/27127/. These pictures may not be reproduced, copied, edited, published, or uploaded to any Site(s) including Blogs without his written permission.)
The physics behind water spikes is remarkably complicated and only recently has their formation been accurately described and simulated. So, like any physicist presented with an insurmountable problem, I’ll make some unreasonable assumptions and cheat (an experimentalist would then drink and make prank calls).
One of the classic cheats is making a list of everything you think your equation should depend on, and then balance the units. Based only on the vague hope that water spikes scale (same shape regardless of size), the energy E of a spike that rises to height H should be 
Here c is some constant that would need to be found experimentally. The graph of 
Your best bet is to avoid generating the spike in the first place. Water spikes are the result of a symmetric air-cavity collapse just below the surface. If the cavity isn’t symmetric, you shouldn’t get a spike. So as you make your Deposit, make sure to wave your butt around. Please let us know how it works out.
Here’s another example of frequently gross marriage between super-computers and fluid dynamics.
Q: Will CERN create a black hole?
Thursday, November 26th, 2009Physicist: Unfortunately, ultra small black holes straddle the line between quantum mechanics and general relativity, which makes it difficult to make useful predictions. The answer is: a solid maybe. If your conCERN is that the black hole thus created will destroy the world, you can relax.
First, the hole will be so small that you couldn’t force-feed it an electron.
Second, the TeV (the energy an electron has after being pushed through 1,000,000,000,000 volts) collisions that CERN is aiming for happen in nature. Statistically, they should happen in the upper atmosphere somewhere in the world a couple times a day. The record is held by the OhMyGod particle detected in 1991, which had an energy of around 300 million TeV. So if we can form tiny black holes, then nature’s already beaten us to the punch. The evidence of these ridiculously high energy collisions come in the form of a “shotgun” wave of intense radiation, that only affect small areas on the ground a couple hundred yards across. You’ve been hit by several of these events in your lifetime, and been none the wiser.
Do to the effects of Hawking radiation (which makes small black holes fizzle out and disappear), the scientists at CERN are working on methods to detect the secondary effects of a fresh black hole evaporating, instead of detecting the hole itself. They don’t expect it to last long enough to get from the collision point all the way to the detectors, which are only inches away.
CERN: The last thing James Bond will ever see.
