Oh, this is Awesome Sauce Music Friday. Thanks for popping in.

We won’t be seeing any more of Commander Chris Hadfield’s awesome space science videos or photos from the International Space Station. Evidently, as of May 14th, he’s once again an Earth-dweller. This week’s music post is Hadfield’s final video from space, at least for a while. He is, quite appropriately, singing “Space Oddity” by David Bowie. It’s been making the rounds on the Interwebz this week, but it’s just so epic that I had to share it here.

According to io9, Hadfield’s son, Evan, had this to say:

He returns home in Soyuz in the early morning of the 14th, and this is his final video from Station. It is also, coincidentally, the first real music video ever recorded in space.

Guys! It’s a music video! From space! The future is awesome.

HT: io9

Want more music? Check out Lab Tracks on Mad Art Lab!

Do you have a delightfully nerdy recommendation? Leave them in the comments, or contact us here.

Featured image credit: David A. Aguilar (CfA)

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Featured image credit: Petr Novák, Wikipedia

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Even though I’m old and irrelevant, I still feel like summer is an awesome time of infinite possibilities. (Infinity also seems to be the upper limit of the midwestern summer heat, by the way.) Sure, you may have some responsibilities, but it’s not quite the same. You can read what you want. Your evenings aren’t consumed with studying. Or, if it is, it’s something you want to learn, not something you have to learn. Even if you love school, there is something freeing about that.

What are your plans for the summer? Do you have any big vacation/internship/vegging out plans? 

Featured image credit: Evil Erin

Featured image credit: Wikimedia Commons

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The idea of an afterlife, as unlikely as it is, has a certain allure. Most of us don’t want to die (cheers for that, evolution), and the idea that our life is but a brief glimpse of a greater version of itself as so compelling that its a central tenant of most of the major world religions and even lives on in the new age ‘greater levels of consciousness’ religion that doesn’t believe it’s a religion.

Leave it to humans to find a really good idea and make it into something awful. As if the idea of being put to death wasn’t horrible enough, our species found a new way to scare the crap out of us all by persuading us that if we didn’t conform to a certain set of moral rules we’d spend an infinity being tortured and punished. The fact that, in St. Paul, the Bible has one of the archetypal redemption stories only makes the idea of burning forever for having homosexual intercourse ironic.

Naturally, hell has sort of faded into the background these days. There are fundamentalists, yes, but it seems that all in all, belief in the eternal suffering of sinners isn’t as ubiquitous as it once was.

The afterlife concept has often been pictured with a sinister side, however. Anyone remember Anubis weighing the hearts of the recently deceased against a feather? And we seem to enjoy a horror story just as much as we like a redemption story, but these days religion seems to be growing into more of a notion of comfort and safety rather than a way to understand the world. In such a world, the dark side of reality doesn’t need to be reflected in religion. With the Christian God, who has grown from a figure to be feared to a fear to be loved, from a lord to a father (though both names are still used), the existence of a hell in a world where he exists is becoming increasingly inconsistent with the way he is explained and believed in.

Hell is the monster under the bed, the dark creature watching you though you know full well you’ll never see it. The monster story that became so much more. In some circles, the threat of it is still used to keep the faithful faithful, but surely, such a fear isn’t a good tool for inspiring faith, because the faith must already be there for the fear to work? A quick google couldn’t help me support or denounce that idea, unfortunately, but even if it isn’t unproductive, it’s an inherently dishonest way of tricking people into a cause that’s supposed to be ‘righteous’. And in my opinion, the fear of death without an afterlife is fear enough to scare someone into belief.

[all images: wikimedia commons]

Featured image: Human Rights Campaign.

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OK nerds! Class is over, which means it’s time to get down and dirty with some physics.

Last time this post had something substantive in it, I discussed the kinetic energy of a rigid rotating body and I introduced a new concept called the moment of inertia. Today we’ll do a couple of example problems and talk about how this all relates to gravitational potential energy. Sounds cool? Then let’s roll.

Let’s do a quick example question on how to find the moment of inertia. Let’s pretend that we’ve built this weird thing consisting of three heavy disks and three lightweight struts. The disks weigh 0.30 kg, 0.10 kg, and 0.20 kg, and the strut lengths are 0.50 m, 0.30 m, and 0.40 m.

I know that none of this makes sense, so here’s a diagram of all the relevant information.

Is that any better? I’m not sure, but let’s just go with it. You might be able to kind of make out that there is an axis in the middle of disk A. The other disks swing around disk A. It’s like disk A is the sun and disks B and C are planets.

Does any of that make sense? Good. Then let’s find the moment of inertia of this body about that axis.

Because the struts are lightweight, we’ll consider them to be massless rods and the disks to be massive particles. By doing so we can use the definition of moment of inertia to find…ugh…the moment of inertia, I guess.

Remember the definition of moment of inertia? Just add together the product of the masses of the particles and the square of the particle’s distance from the axis of rotation. Since we’re considering each individual disk to be an individual particle, and since we know the length of the struts, this will be easy. It’s just a matter of plugging in the values.

Voila! You’ll notice that we just used the mass values from disks B and C and the distances from A to B and a to C. This is because disk A lies on the axis, so its distance to the axis is zero. That means that it would add nothing to the moment of inertia. You know, multiplying by zero and all. But that’s how it’s done.

We can do the same thing if we pretend that our weird contraption could swing around an axis going though disks B and C. In that situation, since B and C both lie on the axis, only disk A contributes to the moment of inertia. So our equation looks like this:

Cool, right? Let’s go back to the first part of this question. We know the moment of inertia for this contraption we’ve made when it swings about the axis in the middle of disk A. If we know the angular speed, we can figure out the kinetic energy.

If you’ll remember, the equation we learned a couple of weeks ago for kinetic energy is the product of the moment of inertia and angular speed in radians, all divided by two. So what is the kinetic energy of our contraption when it has the angular speed of 4.0 rad/s? Let’s find out by plugging in some values.

And there you have it! Pretty easy, right?

This problem, however, just deals with kinetic energy. What do we do when we have to a body that is subject to gravitational potential energy? Let’s pretend for a moment that we have a pulley that’s lifting something. If the acceleration due to gravity is the same at all points on this body, then we can do the math as if all the mass is concentrated at the body’s center of mass. If we take the y-axis to be vertically upward, then the gravitational potential energy turns out to be:

In this equation, y stands for the center of mass, and this equation holds true for all extended bodies, not just rigid bodies.

OK, well, that’s all I have for you today. Next week I’ll probably try to explain something called the parallel-axis theorem. What is it? I don’t know yet. You’ll just have to come back next week.

Featured image credit: ninahale