Could dark energy just be discrete space-time?

If there’s anything in the cosmos more mysterious than dark matter, it’s probably dark energy. It makes up more than two-thirds the energy in the universe and encourages the universe’s accelerating expansion. Yet no one has the slightest clue what it is. Some undiscovered particle? A cosmological constant? Or perhaps dark energy emerges as a sign that space and time aren’t what they seem.

Every graduate student who studies particle theory suspects at one time or another that space-time might be discrete. There's a surprising reason behind that: the sums at the heart of quantum field theory are hopelessly, woefully infinite, primarily because the theory misbehaves at very short distances — ironically, this is exactly the reason it's so hard to figure out a quantum theory of gravity. If we just made it so there was a smallest possible distance, a tiniest possible step you could take, that problem would evaporate. But theorists figured out another way to deal with most of the infinities — one that does a remarkable job of explaining how particles behave — and anyway, how do you define a tiniest step? What should it look like?

Well, it should look like a pyramid. Space and time really might not be what they seem.

That view, recently proposed in the journal PLOS One, stems from a controversial idea called dynamical triangulation. First proposed as a theory of quantum gravity, DT holds that minute tetrahedrons—triangle-bottomed pyramids—are the fundamental units of space and time. Viewed from a distance, these units disappear into the smooth, continuous world of everyday life. Up close, churning stacks of tetrahedrons bend left, right, front, and back—and that’s where dark energy might lie. Calculations suggest that energy stored in the bends is distributed almost uniformly, just as observations suggest dark energy should be. And while the model’s predictions for dark energy’s density are rough at best, they manage to come within a factor of ten of the measured value, something quantum field theory ignominiously fails to do—it misses the mark by a factor of 10^107, or 1 followed by 107 zeros.

An economist walks into a bar...

First, HOLY COW IT'S BEEN A WHILE. Well, that's what having a baby will do to you, I suppose. That, and Twitter. I'm still recovering, but in the meantime, I'll be posting some short stuff I wrote that didn't, for whatever reason, end up in print. Some of it is...old. But still fun! Enjoy.

Cheers,
Nathan E. Science

Liquor is big business in the U.S., and with drunk drivers involved in about 40 percent of traffic fatalities, it’s also a serious public health threat. Acting on the assumption that drinking leads to increasingly risky decisions, many states prohibit happy hours or serving alcohol to clearly intoxicated people. But is the “more liquor, worse choices” axiom correct?

To find out, a team of economists armed with a breathalyzer and a laptop headed to a bar in New York’s Lower East Side. Once there, they asked 317 men and women of varying inebriation to make different bar-oriented decisions—between different combinations of sliders and dumplings, or between different cash lotteries—all the while looking for subtle inconsistencies in their subjects’ choices. Remarkably, even stumbling-drunk participants made sensible choices. The main exception: as they drank more, women became slightly more comfortable taking risks when choosing between lotteries.

If confirmed by further experiments, the results suggest that efforts to curb drunk driving or other negative consequences of drinking should focus on making better decisions while drinking rather than on discouraging drinking in the first place. The paper appeared last June in the Journal of Risk and Uncertainty.

People Are Ignorant. Big Deal, Right? Well, Yeah.

We've been on the theme of political ignorance for nearly a month now, and so far we've concluded that people are generally pretty ignorant, but we don't yet understand whether this is such a bad thing. Recall from last time there were three arguments about whether political ignorance matters.

Science, Reporters, Teaching, and More Coffee: Part II

Every year, or most every year at least, I head off to Eastern Washington University to teach and counsel at Satori, a summer camp for kids who like to learn stuff—and learn them we instructors do. But in between learnings, there’s a lot of time for conversation and a lot of time for a lot of coffee. Seeing as I’m a reporter now, I have an excuse to talk to anyone about anything, so I asked Thomas Hammer barista-manager Abby* whether she’d talk with me about science. She cheerfully obliged, though she also had to work. When she was off doing that, Satori director and Spokane school teacher Mike Cantlon filled in, making for an interesting back-and-forth that ranged from—well, this to that and a number of places in between.

Science, Reporters, Teaching, And More Coffee: Part I

Every year, or most every year at least, I head off to Eastern Washington University to teach and counsel at Satori, a summer camp for kids who like to learn stuff—and learn them we instructors do. But in between learnings, there’s a lot of time for conversation and a lot of time for a lot of coffee. Seeing as I’m a reporter now, I have an excuse to talk to anyone about anything, so I asked Thomas Hammer barista-manager Abby* whether she’d talk with me about science. She cheerfully obliged, though she also had to work. When she was off doing that, Satori director and Spokane school teacher Mike Cantlon filled in, making for an interesting back-and-forth of sorts that ranged from—well, this to that and a number of places in between.

In case you missed it...

A few, short, cool stories I did for ScienceNOW. Check them out. Comment and ask me questions in the comments!

When Predators Attack!
Watch out!

Toward Shatterproof Glass
Possibly helpful when dealing with predators.

How to cloak a Fisher space pen...or a satellite

There's an apocryphal story that, faced with the fact that ballpoint pens don't work in zero gravity, NASA paid a lot of money to develop the Fisher space pen. Meanwhile, the Russians used pencils.

"A Snapshot of the Inside of an Atom" at ScienceNOW

My first story for ScienceNOW in quite a long time, and it's a fun one. Scientists at FOM Institute AMOLF took a picture of the quantum wave function of electrons as they emerged from hydrogen atoms.

Wave function? AMOLF? Google the latter. As for the former, the wave function is the fundamental piece of quantum weirdness, something that physicists have tried to wrap their heads around for eighty or ninety years — and failed. For more, read the story.

Seeing the Forest for the Splotchy Green Blob

Lesson for today: statistics is hard. Specifically, it's hard to sort out real patterns from random noise, especially when you don't have a lot of data. Nonetheless, people sure do their darndest.

Coffee Science with Four Barrel's Alex Powar

We're talking chemistry. Sort of. "Chlorogenic acid, for instance, esterizes into quinic and caffeic acid. Quinic acid...so that produces a lot of bitterness. That's why you never want to reheat coffee. It catalyzes that reaction."

These are a few of my favorite sciences.

What's your favorite thing about the natural world? There are lots of things to choose from. The profound tension between natural selection and biological diversity. The fact that no matter how fast you're going, you'll never catch up with a beam of light. The way snowflakes form.

Nathan Explains Science Just Voted, and You Can Too.

I just voted. You should too. Well, if you're 18 or older, anyway.

Errol Morris usually says it better.

Nathan Explains Science has spent a fair amount of resources to convince you that politics doesn't work quite the way that pundits would like you to believe. Among the topics: the many reasons — sometimes arguably legitimate — not to vote. Among them, your vote is unlikely to count, and even if it counted  toward deciding your state's electoral college votes in a presidential election, your state's choice might not ultimately matter. Who gets elected might not matter — though Nathan Explains Science emphatically denies that assertion as it applies to recent presidential elections.

On the other hand, if no one votes, then anybody who does makes the decision for everyone. Thus, in an incremental sort of way, the fact that you vote makes democracy just a little bit safer.

I'm bringing this up because Errol Morris, innovative director of the documentaries The Thin Blue Line and The Fog of War, just shot a short film on the subject of why we don't vote. You can view it here:  11 Excellent Reasons Not to Vote. It's about seven and a half minutes, and Morris does not disappoint.

I'd love to hear your thoughts.

Nathan Explains Science Was Going To Blog About The Debates, But....

Dear Readers,

Nathan (of Nathan Explains Science fame) really wanted to explain why he (and many others) won't be watching any of the (vice-)presidential debates, but he's been working hard all day, he's tired, it's the bottom of the 7th and the O's are tied with the Yankees in the ALDS, he's already decided whom he's voting for, the election isn't all that exciting this year, and he should probably make some dinner.

Catch all that? Good. Anthony Downs and I are proud we've taught you something. More next time.

Cheers,
Nathan Explains Science

LA Cars and Santa Fe Bars: Carmageddon 2 and the El Farol Problem

Think fast: what do the freeways of Los Angeles have in common with a bar in far-away Santa Fe, New Mexico? This weekend, it turns out, quite a lot.

Nathan Explains Romney...Maybe...

By now you've likely heard all about the Super Secret Awful Romney Video, uncovered by Mother Jones and covered by basically everyone from the Washington Post to Drudge.*

Politics, Decline, & Stress Balls

In my last post, I wrote about how important it was to pursue seemingly odd social and political science, and I cited as an example a study that showed squeezing a stress ball can make you more likely to believe random strangers were Democrats.

Weird (Social) Science, and Why We Need It

Social psychologists in particular are fond of what Lee Ross once called "demonstration experiments," that is, experiments that show in more or less dramatic fashion the weird things you can get people to do if you try hard enough. Even social scientists have derided demonstration experiments as goofy, sometimes useless, but they have their value.

Nathan Explains Science on Santa Fe Radio Cafe

Sadly, my real job has kept me from doing my real avocation, blogging, and it's especially unfortunate this week since the Republican National Convention is in full swing just in time for hurricane season.

But fear not!

The lovely and talented Mary-Charlotte over at Santa Fe Radio Cafe interviewed me recently on matters political, and you can listen here:

http://www.santaferadiocafe.org/podcasts/?p=2961

Jesus? He's On Your Side

A string of attacks on religious institutions including Muslim and Sikh houses of worship got me thinking about the sort of psychology that justifies these things. That led me indirectly to one of the more significant questions of our time: What would Jesus do?