Shooting an AK-47 Underwater

Here in the US, we seem to be obsessed with guns, with our right to own them, and with the ridiculous fear that the government is going to try to take them away from us. Predictably, the people who are most vociferous on the issue are not exactly luminaries and scholars with a solid understanding of constitutional law and jurisprudence, which is really putting it mildly and generously...

But since this is a blog dedicated (for the most part) to sharing education and interesting ideas, why don't we take this obsession with guns to watch someone shoot an AK-47 underwater and, most importantly, to learn some fascinating principles of physics to understand what it is that we have just seen?

Explosions and physics... awesome!

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Brian Cox - Wonders of Life - Expanding Universe

Our knowledge of the world comes from our experience of the world. And our experience is based on our sensory apparatus, but how do our senses work? What is it about the physical laws of the universe that make it possible for creatures like us to perceive anything at all?

In the following documentary, Brian Cox visits some interesting animals in the US (giant catfish, glowing scorpions, mantis shrimp and octopi, among others) to explore and understand how they, and we, are able to create mental representations of our environment through taste (chemicals), sound (air waves) and vision (light), and how it is that the gradual process of evolution through natural selection has slowly sculpted the amazing machinery of perception, by taking fish jaws, for instance, and slowly turned them into the ear bones that make hearing possible for you and me...

To catch that catfish, he didn't have to enlist the help of a scientist... he could have just told a redneck to go noodling :)

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Lucretius - De Rerum Natura - Matter and Void

In his fascinating book, The Swerve, Stephen Greenblatt tells the gripping story of the rediscovery, during the Middle Ages, of one of the philosophical masterpieces of the Classical period in Rome: Lucretius' De Rerum Natura (On the Nature of Things), an epic exploration and development of Epicurus' materialist, empiricist and soteriologically hedonistic philosophy, all set to the most beautiful of Latin poetry.

Greenblatt shows how the Christian obsession with asceticism, suffering and self-righteousness came perilously close to annihilating any traces of a philosophy that eschews the supernatural, and that celebrates life and sees it as worth living and enjoying. It was by sheer chance that an Italian humanist scholar, Gian Francesco Poggio, discovered Lucretius in a palimpsest and started circulating it. In Greenblatt's opinion, the dissemination of this beautiful work of antiquity (measured by the famous thinkers who managed to get their hands on and were inspired by it), may have been one of the leading factors that gave rise to modernity.

In the following audio rendition, read by the inimitable Charlton Griffin, you'll get a sense of the piercing power of Lucretius' philosophy and poetry as he sets down the basics of Epicurus' metaphysical materialism and his fight against religion. They say the pen is mightier than the sword, but in Lucretius' hands, it's more like a nuclear bomb!

This is just the beginning... stay tuned for more excerpts from this fascinating work!

And if you're interested in the text of the above excerpt, you can find a copy here.

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Physicists Confirm They Found and Killed the 'God Particle'

Virtually since the inception of its moniker, many atheists have hated the fact that the Higgs Boson, a theoretical subatomic particle thought to be responsible for attributing mass to matter, has been referred to as the "God Particle."

But as The Onion reports, they may finally have reason to celebrate, as news have been revealed that physicists have finally found, and then killed, that goddamn particle...

But if you actually want to get an idea of what the Higgs Boson and the Higgs Field are, you can check out the LHC tag, or just watch this short clip with the awesome Sean Carroll:

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Philosophy of Time

Sorry about the sparse entries lately. My mind has been busy with a bunch of personal stuff.

So today is the release of the last installment of The Dark Knight series, so I figured you're probably looking for some sort of light-minded stimulation to deal with the inevitable boredom, and I thought to myself, why not have a little introduction to the philosophy of time? It's precisely the kind of subject that makes a summer Friday go by all the more quickly :p

Obviously, this is a bit old, and just barely scratches the surface of this topic, but I hope you can see that time presents all sorts of interesting and paradoxical questions for which we don't yet have a fully satisfactory understanding. That opens up the possibility that maybe you'll be the person to figure it all out one day, so get to work! :)

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Olber's Paradox - Why Is the Sky Dark at Night?

I know that may seem like a silly question at first glance, but there is a long history of seemingly silly questions that end up producing some mind-blowing and really counter-intuitive results that really get us to question our most basic presuppositions about the nature of reality, and in many cases redefine our understanding of the universe. This case is no exception.

So back to the question, sure, the sun is hiding on the other side of the planet, but there are stars in literally every possible direction, so photons are hitting us all the time from every possible direction. But if this is the case, shouldn't the night sky look bright from all these stars?

Well, as the following simple animation brilliantly demonstrates, the sky really is bright from all those stars... we just can't see all that light, not with our eyes anyway, but it is there, and what that tells us about cosmology and the universe is absolutely fascinating!

Bet you didn't see that coming, huh? No pun intended, actually. I was just blown away by the connections. This stuff is awesome :)

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Getting to Mars - Curiosity's Seven Minutes of Terror

On their own right, the semi-autonomic rovers that explore the surface of Mars for us are great feats of engineering. The fact that they do what they do (from such a long distance away it's virtually impossible for us to really wrap our heads around) ought to be enough to impress anyone, but have you wondered how it is that they get there in the first place?

As you may recall from memory or a little history, landing on Mars is no easy feat. Its gravity is relatively similar to our own, but its atmosphere is too thin and light, so even if you get the angle of entry right (and that's a huge challenge in its own right), you still have to contest with the fact that you're falling at vertiginous speeds without much to slow you down sufficiently for a smooth touchdown.

So, how do you do it without smashing to smithereens all the equipment you want to use? Once it hits the atmosphere, the rover has an infamous seven minutes of terror to deploy a number of very delicate and specifically programmed functions about which you'll learn in the following pretty dramatic animation:

How would you do it?

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Slinky Magic in Slow Motion

If you've been following this blog for a while, then you probably already know the answer (and the explanation) to the following question: if you hold on to one end of a slinky and let the other side hang down until it stops moving, what would happen to the bottom end exactly when you let go of the top? Does it move up because the spring is no longer being stretched? Does it stay still? Does it fall because gravity is pulling down on it and there's nothing holding the slinky any longer?

If you haven't checked out that entry, go right now. But because this sort of thing is just too cool, today we have another video on the topic, with the added beauty of a longer slinky and some incredible slow motion photography:

And for more awesome photography, visit our awesome time lapse tag.

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Shock and Awe: The Story of Electricity - Spark

The ancient Greeks knew that if you rubbed two pieces of amber, you'd produce static electricity, but apart from that, it would be another two thousand years until this weird, invisible, ephemeral, mysterious and (literally) shocking phenomenon would be systematically studied, controlled, stored, understood and made to flow continuously. But as with any nascent science, there were false starts, one question answered only leading to more questions.

In this first installment of the documentary series Shock and Awe: The Story of Electricity, professor Jim Al-Khalili explores the history of the scientific exploration of electricity through the work and incredible creativity and experimental rigor of luminaries such as Pieter van Musschenbroek with his Leyden Jar; Benjamin Franklin's famous explanation of electricity as a liquid with positive and negative charge,  and yes, even the apocryphal kite story, demonstrating, like Newton had done before, that phenomena previously presumed to be heavenly in kind (thunder and lightning) were actually just instances of the same general laws that apply to mundane objects here on Earth; Henry Cavendish's experiments with the torpedo fish, which gave rise to the distinction between electric charge and voltage; Humphrey Davy's popular demonstrations at the Royal Society; the fascinating (and somewhat gruesome) dispute between the "animal" electricity of Galvani and the "no-nonsense" secular electricity of Volta; ; the isolation of chemical elements; and the prospect of resurrection and life after death...

Pure awesomeness :)

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Brian Greene - Why Is Our Universe Fined-Tuned for Life?

Have you noticed that wherever Brian Greene goes, computer animations go with him? Well, this TEDTalk presentation is no exception :) I'm starting to wonder whether this might be the physicist equivalent of a comfort blanket...

In any case, and as you may expect if you're familiar with him, he lays down the case for string theory, and explains some of the fascinating implications if string theory and the cosmological theory of inflation were true. Even as mere hypothetical possibilities, these ideas merit our attention.

What I do have a major problem with, however, is his "explanation" for why our universe is fine-tuned for life. It's a version of the anthropic principle that is either completely backwards or completely question-begging (circular)... or both... I'll let you be the judge:

The analogy with our distance to the sun doesn't quite work because, despite his explicit claim to the contrary, it's asking one question but answering another. Our distance to the sun doesn't explain why Earth is  x-number of miles away from the sun (see what I mean by circular?). It doesn't tell us anything about astronomy or physics.

What it explains is why we live on Earth and get to ask that question, but it tells us nothing about the conditions that led to our planet being where it is... Similarly, the fact that we happen to inhabit the particular kind of universe that contains the conditions that allow for life-forms such as ours tells us nothing about why this particular universe happens to have those particular features.

In other words, you can't answer the question of why is our universe fine-tuned for life by answering that it's because our universe is fine-tuned for life... or am I missing something here?

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Ring of Fire Eclipse Moon Shadows

I've always loved (and been curious about) how leaves distort the path of light waves. If I were to speculate, I would guess that maybe they... actually, who are we kidding? I have no idea, plain and simple. Anyone out there who can help?

So I'll admit that I don't quite get the mechanism, but when you combine that weirdness with the Ring of Fire eclipse that occurred a couple of days ago, what you get is a thing of beauty:

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The Higgs Boson Explained, PhD Comics Edition

You may remember that a while ago we featured a PhD Comics animation explaining Dark Matter.

Today we have another episode dealing with those two or three words that you may have heard numerous times in reference to the Large Hadron Collider over the past couple of years, and which is the main reason the whole thing was built to begin with: the famous Higgs Boson mechanism.

You may know that it's got something to do with explaining why particles have mass, but if you don't know anything more than that, here is your chance for a fun primer:

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Just How Small Is an Atom?

When it comes to the world beyond our direct, ordinary experience, we just don't have what it takes to understand the differences in scale. If you are given a model Earth and Moon made to scale, for instance, and you're asked to estimate how far apart they would have to be from each other to represent their true distance, most people fail this test miserably. Same thing if you ask people to describe the relationships between the constituent parts making up an atom. So, to help with that problem, here's a quick little lesson on understanding just how small an atom is, and a few other fun facts:

They made things for difficult for themselves than they really had to with that density scenario, didn't they?

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Strange Charm: A Song about Quarks

Unless you're a physicist or a physics enthusiast, you probably have a hard time remembering the difference between subatomic particles such as quarks, electrons, protons, neutrons, leptons, gluons, hadrons, positrons, bosons and morons. Ok, fine, maybe you definitely know a moron when you see one, but you get my point.

So, if you want to learn how to remember the difference between all these particles, the following totally geeky but catchy song should be just what you've been looking for:

And for more funny and educational songs, check out the funny songs tag.

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To Infinity and Beyond

Apparently the title of this documentary also has something to do with Toy Story? Well, I haven't seen that movie, but I can tell you what this documentary is about... Infinity. The most obvious way to start thinking about infinity is through numbers: take any number, and you'll soon realize that there is no such thing as the biggest number because you can always add 1. No, a googol won't do it, nor even a googolplex or Graham's number. Yes, these numbers contain more zeros than there are atoms in the observable universe, but they still fall short, infinitely short, in fact, of infinity.

But the strangeness doesn't end there because infinity may not only be a mathematical conceptual idea: infinity raises all kinds of interesting scientific and philosophical questions and paradoxes (what Immanuel Kant called antinomies of reason) about the physical universe that even modern cosmology doesn't quite know what to do with: is space infinite? If not, what's beyond its edge? Infinite empty space? What about time? If it is, and the amount of matter in the universe is finite, then everything that could logically happen has happened, and will continue to happen, an infinite number of times... And hey, are there an infinite amount of universes? And as you'll see in this fascinating documentary, this is just the beginning of the weirdness:

For a fascinating treatment of the problems of infinity, check out the documentary Dangerous Knowledge.

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The Fabric of the Cosmos - The Illusion of Time

In the first episode of the Fabric of the Cosmos series, we learned a little bit about the weirdness of space, so hopefully that massaged your brain enough for something even weirder: time.

Philosophers and scientists have been trying to understand what time is since antiquity, and one thing that they have found is that it's incredibly difficult to say anything about time without already presupposing it in some sort of viciously circular argument. Nevertheless, curiosity drives us to ask questions that we then have to test by conceptual analysis and by empirical means, and we often find out that these come in conflict with each other in ways that elude simple solutions.

There are philosophical accounts of time (and I'll provide a short introduction soon), as well as scientific accounts, most of which are based to various extents on some of the incredible insights to come out of Einstein's theories of special and general relativity.

So fasten your seat-belts as Brian Greene takes us on a tour to understand some of the deepest of mysteries: What is time? Does the past exist? Does the future? Can we change the future? Can we travel back in time? If so, can we change the course of history? And hey, if you can go back in time and meet your former self, which one is really you? That last one is more of a philosophical question, just to show you how badass we are :)

If your head isn't spinning by now, then you might want to get yourself checked into a hospital :)

And if you want to watch the original from NOVA, here it is:

Watch The Fabric of the Cosmos: The Illusion of Time on PBS. See more from NOVA.

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Schrödinger’s Cat... in 60 Seconds

We've seen in previous episodes of this 60-second Adventures in Thought series, all sorts of philosophical, logical, mathematical and scientific paradoxes and all-around weirdness. To remind you, we've seen Zeno's paradox concerning motion, the grandfather paradox concerning backward travel through time, John Searle's chinese room thought experiment concerning thought and computation, Hilbert's infinite hotel concerning different size infinities, Einstein's twin paradox concerning special relativity.

And finally, today we have Schrödinger’s Cat, that poor kitty whose bivalent fate rests upon the superposition of subatomic particles...

For a more serious treatment of Schrödinger’s Cat, check out Jim Al-Khalili's documentary Atoms: The Illusion of Reality.

And for more on infinities, you'll do your brain a favor by watching the excellent documentary Dangerous Knowledge.

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The Fabric of the Cosmos - What Is Space?

That's probably not the first question that comes to mind for most people when they wake up in the morning, but it is definitely one that has kept some of the greatest minds of all time awake at night. What exactly is space? Is it a substance? Is it merely a relationship between objects? Whatever it is, is it static or dynamic, absolute or relative, immanent or transcendent? If there no physical objects in the universe, would empty space still exist, or is that an incoherent question, like asking what happened before the beginning of time? Join Brian Greene in a fascinating (if gimmicky) exploration of one of the most fundamental scientific and philosophical questions in this first episode of The Fabric of the Cosmos:

And in case the youtube video stops working at some point, here's the original from NOVA:

Watch The Fabric of the Cosmos: What Is Space? on PBS. See more from NOVA.

For more related videos, check out the Elegant Universe Tag.

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Faster Than the Speed of Light?

Some months ago, news broke indicating that scientific measurements in Italy had determined that some neutrinos could travel faster than the speed of light. The media jumped on the hype bandwagon and declared the "death of Einstein's theory of relativity." Physicists (aka, the experts on these questions) were skeptical because ALL previous experimental and observational data, including neutrinos and light traveling from super nova explosions really really far away and reaching Earth at exactly the same time, confirmed Einstein's predictions, so they concluded there must have been some error in the measurement, the analysis, the equipment, etc. on which the Italians relied. Of course, there were also cultural reasons for doubt: as Sergio Bertolucci, research director at CERN indicated, "I have difficulty to believe it, because nothing in Italy arrives ahead of time." :)

News are starting to pop up everywhere now that there was indeed a glitch in the equipment. Still, whatever the real answer turns out to be, and since everyone seems to be paying attention to the story, this presents a great opportunity to learn some fundamental lessons not only about relativity and other ground-breaking research in theoretical physics and cosmology, but how science itself works and makes the tremendous progress it does, so let's watch this delightful documentary narrated by Professor Marcus du Sautoy:

Sometimes I do wonder whether these physicists are insane in the mem-brane :)

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Richard Dawkins & Lawrence Krauss - Something from Nothing

One of the most persistent intuitions we humans rely on when thinking about the question of the origin of the universe is captured by the latin phrase ex nihilo nihil fit, which can be roughly translated as "nothing comes from nothing," so where did everything come from?

On the one hand, you can argue that since ex nihilo nihil fit, the universe, in one form or another, must be eternal and must have always existed. One potential problem with that point of view is the question of whether actual temporal infinities can really exist. On the other hand, the traditionally preferred answer has been: God did it. Of course, this answer doesn't explain anything, since it leaves the question of how even God could have created something (everything, in fact) from literally nothing, unsolved. Yes, God of the gaps argument, not a real solution.

But the question remains: where did the universe come from? And in the following fascinating, amusing and thought-provoking conversation, evolutionary biologist Richard Dawkins and theoretical physicist Lawrence Krauss tackle this and other equally important and interesting questions. Of particular interest is Krauss's distinction between the way scientists understand "nothing" from the way theologians understand the same word. It's a really interesting way of turning the question around on the believers. I wonder what you'll make of it...

Hope that leaves you with an intellectually satisfying weekend.

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