Category Archives: Double X Science

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My cats, Pascal and Harriet, with a few of my books that deal with the topic of relativity.

My cats, Pascal and Harriet, with a few of my books that deal with the topic of relativity.

Albert Einstein is many people’s archetype of the genius scientist, and his most famous equation is E = mc2. Or is it? When you look at Einstein’s published scientific papers over decades of work, he didn’t (usually) write the equation in that form. In fact, he pointed out that was an inaccurate form, since it’s a limiting case of a far more general principle. In my latest piece for Double X Science, I argued that the form of the equation is far less important than its meaning, and it doesn’t really matter if Einstein wrote E = mc2 or not.

When you study relativity, you find those equations are specific forms of more general expressions and concepts. To wit: The energy of a particle is only proportional to its mass if you take the measurement while moving at the same speed as the particle. Physical quantities in relativity are measured relative to their state of motion – hence the name. [Read more...]

Did Einstein ever write his most famous equation?

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The real poop on human digestion

I won’t lie: I love Mary Roach‘s books. She is likely the funniest nonfiction writer working today; her beat is the weird side of science. I reviewed her most recent book, Gulp: Adventures on the Alimentary Canal, for Double X Science:

Consider this question a 6-year-old might ask: Why doesn’t the stomach digest itself? After all, the human stomach contains hydrochloric acid, which is uses to break down some pretty tough substances for digestion. The answer, as Roach points out, is that it does: The acid dissolves the lining of the stomach over the course of a few days, but new cells replace the destroyed ones. When a person dies, no new cells are born, leaving the acid to work undeterred…with predictably gross results.

However, Gulp isn’t a gross-out book, though I don’t advise you read the chapter on coprophagia (poop-eating) during lunch, as I did. [Read more...]

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In a certain sense, it’s easy to keep things in orbit around Earth. However, it’s hard to keep satellites in a specific orbit, which is what matters most for communicating with them and they with us, whatever task they’re designed to perform. Thanks to the work of rocket engineer Yvonne Brill in the early 1970s, the process is remarkably automatic.

Brill’s design eliminated this redundancy and lightened the spacecraft in the process. She also used a type of fuel called hydrazine, which is so reactive you don’t need oxygen or another chemical injection to ignite it. (On Earth, we’ve got lots of oxygen available for making things burn, but in space, you need to carry your own fuel for fire.) Brill’s system pumped liquid hydrazine through an aluminum nozzle. The chemical composition of the nozzle reacted with it, splitting it into smaller molecules and releasing a lot of energy. [Read more...]

I’m no rocket scientist, but I can appreciate the challenges of engineering something that needs to stay in the same orbit for years or decades. Yet the New York Times obituary for Brill mentioned her remarkable achievements as a sort of afterthought, as though they weren’t very important, really, in the scheme of things. My piece isn’t an obituary—I mostly write explanatory pieces about science, after all—but Brill’s contribution to spaceflight in general and the communications satellite revolution of the 1980s is astounding.

Yvonne Brill and the technology keeping satellites in orbit

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My review of Brian Switek’s forthcoming book, My Beloved Brontosaurus, is up at Double X Science!

Suffice to say, these are not the dinosaurs I learned about as a young kid—and in my opinion, they’re much more interesting. Over the last few decades, the basic realization that modern birds are living dinosaurs has grown, and helped us understand their extinct uncles and aunts: the dinosaurs of the distant past. (Many scientists even refer to the classic dinosaurs as the non-avian dinosaurs, meaning these are the ones that aren’t recognizably modern birds.) For example, hollow yet sturdy bones allow modern birds to fly, but they also allowed sauropods to grow into the biggest animals ever to live on land. We also know now, thanks to a number of recent finds, that probably every dinosaur lineage had feathers of some sort. As Switek wrote, “Just think of how cute a fuzzy little Apatosaurus juvenile would be.” I concur. [Read more...]

Dinosaurs belong to all of us

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Double X Science chemistry editor Adrienne Roehrich started a new podcast series, discussing stories of the week. Her first cohost was…me! We talked about important women in biochemistry, the size of protons, the science of procrastination, and cosmic rays—all in 15 minutes.

You can download the podcast from the Double X site, or subscribe through Feedburner. Adrienne is also working on listing our content on iTunes; I’ll update when that happens. Update: the podcast is now available on iTunes!

Procrastination and protons

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Pascal the cat knows about particle physics.

Pascal the cat knows about particle physics.

It’s fundamental and natural to ask this question about an object: “how big is it?” For many things—most everyday objects, people, planets, stars—size is easy to measure. However, other things are more challenging, including the size of a proton: one of the three particles that make up every ordinary bit of matter. The major challenge is its tiny size, which precludes using light of any kind to measure it. To make matters worse, the size of a proton may depend strongly on what method you use to measure it, as I explained for Double X Science.

The simplest way to measure the size of a proton involves shooting electrons at it, and measuring the paths the electrons take as they feel the influence of the various forces. Because of those forces, in fact, the proton can’t be said to have a single size! Instead, physicists use three different size measurements, which are all pretty close to each other, but not exactly the same. The one most important to us for this post is the charge radius. Electron bombardment measurements found that to be about 0.88 femtometers.

However, electron bombardment only gets us so far; if we want better accuracy, we need another method. [Read more...]

How big is a proton?

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The band has stopped playing, but we keep dancing
The world keeps turning, the world keeps turning.
–Tom Waits

A lot of nonsense has been written over the years about various “prophecies” predicting the end of the world, including stuff by people who should know better. What you see in newspapers, magazines, and TV shows might lead you to believe there is credible reason to think the world will end tomorrow: December 21, 2012. Supposedly this was predicted by the Mayan calendar. However, as with so many things, the truth is much different. The Mayas didn’t predict the end of the world, and there’s no evidence they thought that way. More importantly, there’s no scientific reason to think the world will end tomorrow: nothing we know of could bring about our end so rapidly without warning. That’s a reassuring thought to me, as I wrote in Double X Science today:

My confidence comes from science. I know it sounds hokey, but it’s true. There’s no scientific reason—absolutely none—to think the world will end tomorrow. Yes, the world will end one day, and Earth has experienced some serious cataclysms in the past that wiped out a significant amount of life, but none of those things are going to happen tomorrow. (I’ll come back to those points in a bit.) We’re very good at science, after centuries of work, and the kinds of violent events that could seriously threaten us won’t take us by surprise. [Read more....]

The band has stopped playing, but we keep dancing

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I admit, I love flipping through SkyMall when I’m on airplanes. However, the catalog is chock-full of pseudoscience, as with today’s entry in “As Seen on TV!”, my occasional feature over at Double X Science. (Warning: contains my balding scalp.)

Ah, lasers. They may not have the mystique of magnets or the nous of “natural”, but they are a frequent ingredient in modern snake oil. (Come to think of it, one of the hair-restoration products may have contained snake oil. I don’t want to ask.) But while lasers can help correct nearsightedness in some cases, perform minimally invasive surgeries, and remove hair, color my scalp skeptical about their ability to restore hair. [Read more...]

The bald(ing) truth about laser hair-restoration treatments