Note (12/2015): Hi there! I'm taking some time off here to focus on other projects for a bit. As of October 2016, those other projects include a science book series for kids titled Things That Make You Go Yuck! -- available at Barnes and Noble, Amazon and (hopefully) a bookstore near you!

Co-author Jenn Dlugos and I are also doing some extremely ridiculous things over at Drinkstorm Studios, including our award-winning webseries, Magicland.

There are also a full 100 posts right here in the archives, and feel free to drop me a line at secondhandscience@gmail.com with comments, suggestions or wacky cold fusion ideas. Cheers!

· Categories: Physics
What I’ve Learned:

Special relativity: out with the aether, in with the aother.
“Special relativity: out with the aether, in with the aother.”

On the heels of the holiday season, you may have recently witnessed instances of “special relativity”. Grandma’s secret-recipe fruitcake pucks. Your uncle’s uncomfortably falsetto rendition of “O Holy Night”. Cousin Lem’s drunken faceplant into a bowl of Christmas bisque.

Happily, that’s not the only sort of special relativity. One hundred and ten years ago, Albert Einstein (with a little help from his friends) developed a theory that explained the behavior of things that travel near the speed of light. Like New York City taxis, or Usain Bolt. Or, you know, light.

This theory was needed because by the late 1800s, scientists had figured out that their plain old regular-speed relativity — based on work by Galileo and Newton, among others — wasn’t always getting the job done. This old school theory, called Newtonian relativity or Galilean invariance, because see the previous sentence, sport, said there is an “absolute space” and an “absolute time”, in which everything happens. And by that time, it also included an “absolute reference frame”, a universally unique point of view from which electromagnetic wave properties like the speed of light could be accurately measured.

Problem was, experiments suggested that if that uniquely-accurate reference frame (known as the “aether”) existed, all measurements made in labs were consistently in agreement with it. In other words, all those labs were stationary with respect to this spatial frame of reference. Which would be super, if we didn’t know that the Earth is constantly swooping around the sun (and the sun around the Milky Way, and the Milky Way hurtling through the universe), so it’s not really “stationary” compared to anything but itself.

Einstein dropped this “aether” concept down the nearest aelevator shaft, and that was just the beginning. He also decided that space and time were two great tastes that taste greater together, and mushed them together into something called “spacetime”. And he said no matter how fast you’re going (or not), the speed of light will always look the same. That let a whole bunch of crazy — but later experimentally verified — cats out of the physics bag. For instance:

Under special relativity, two people moving at different speeds may watch the same event happen, but observe it occurring at different times. And not just because one of them has TiVo, either.

If you watch two clocks — one moving and one sitting still — the moving clock appear to go slower. (And if it’s moving while you’re sitting in your office at ten minutes til five on a Friday afternoon, it’ll appear to go reeeeeeeeally slow.)

Mass and energy are equivalent, as given in Einstein’s famous special relativistic equation, E = mc2. This is obvious to anyone who’s eaten a four-ounce chocolate eclair and felt the kajillion-calorie jolt to their metabolism as the mass is converted to energy… and then seen six pounds of flab appear on their ass as it converts back to mass.

(I don’t know why it gets bigger in the conversion. What am I, some wild-haired German genius math guy?)

Basically, Einstein’s special relativity theory made some predictions crazier than drunk old Cousin Lem on an eggnog bender, but they turned out to be true where Newtonian relativity did not. Either theory will get you through the day for normal stuff — but if you’re zooming around near the speed of light, then you’d damned well better listen to Einstein.

He may not be your relative. But believe me — he’s special.

Actual Science:
LiveScienceWhat is relativity?
American Museum of Natural HistorySpecial relativity
HowStuffWorksHow special relativity works
io9Get pelted every day with particles that confirm special relativity
The Physics ClassroomRelativistic length contraction

Image sources: QuickMeme (it’s all relativity), Telegraph (UK) (blurry Bolt), Food Navigator (food faceplant), London Evening Standard (an eclair and present danger)

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· Categories: Astronomy, Physics
What I’ve Learned:

Gravitational lensing: mirror, mirror in the sky; show me what's behind this guy
“Gravitational lensing: mirror, mirror in the sky; show me what’s behind this guy.”

If you’ve ever sat behind a really tall person at a movie, then you know the infuriating problem of not being able to see something on the other side of a solid object. At the theater, you probably deal with this in the usual ways — hoping the heighty person slouches in their seat, or spontaneously loses six inches of height, or their head explodes like in that Scanners movie.

But astronomy tells us there’s another viable option, known as gravitational lensing. All you have to do is push the movie a few million light years away, and make that big fat head in front of you as dense as a ten-billion star galaxy.

It’s a little complicated. I’ll explain.

One of the (now-famous) predictions of Albert Einstein’s general theory of relativity is that space (really spacetime, but who’s counting?) is curved, and that hugely massive objects with lots of gravitational force will further warp that curving. So if a celestial light source — like, say, a quasar — lies behind an enormous gravitational well such as a galaxy, the light from the quasar would get curved around the galaxy and slingshot out the other side.

It might appear that the light source lies beside the big heavy thing in the way, because the light doesn’t bend all the way back to the middle. And if the source is directly behind the obstacle, the light could take more multiple paths around it — left, right, up, down, south by southwest — and appear more than once on our side. It could even form a full ring of light all around the object in the middle, weirdly indicating that the thing producing the light isn’t anywhere around the obstacle at all, but directly behind it.

I know, right? It’s spooky. Real call is coming from inside the house stuff.

Because Einstein described relativity, and was a generally awesome dude, the light rings caused by gravitational lensing are called “Einstein rings”. There are very few complete rings — caused by a massive energy source directly behind a star or galaxy — but hundreds of partial rings, multiple-image systems and other gravitational lensing events have been observed. One of the most impressive, called Einstein’s Cross — because, again, cool smart guy — consists of four “bent” images of a way-distant quasar curved around a still-way-distant-but-not-as-way-distant galaxy in between.

It’s like having a head in the way, but still seeing the movie in double-stereo-vision. Because astronomy makes everything better.

So what do you need to make gravitational lensing work? First, a source of some kind of energy. Many of the known ones work in visible light, but any kind of electromagnetic energy will do in a pinch. The universe isn’t picky.

The energy source has to be ridiculously strong, though, because you’ll need to see the signal from way far away. Not just from down the block, or from that window in your attic, either. Instead, from billions of light years away. Which is kind of a big deal.

Why so far? Because you then need to find an incredibly massive object to plop between you and the energy source to produce the gravitational lensing. A bowling ball isn’t going to do it. A star might, if it’s in precisely the right orientation. A whole galaxy of stars would be better. Or you could try Nicki Minaj’s ass. It’s big enough to attract most of the pop culture paparazzi into a close orbit, apparently. Maybe it could work; I don’t know.

The point is, you’ll only see gravitational lensing by throwing that hypermassive whatever between you and and the signal. And then you can watch that gravity well bend electromagnetic waves like Beckham, off a straight line and down to your eyes.

So maybe it won’t help you the next time you’re blocked at the movies. But gravitational lensing could show you a star behind another star some day. And really, isn’t that how the movie industry works in the first place?

Image sources: Cosmic Chatter (Einstein ring), Slate (big head at movie theater), Disease Prone (Scanners head), SlamXHype (rocket-powered Minaj)

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· Categories: Astronomy, Physics
What I’ve Learned:

Black holes: scarier than galactic Bieber
“Black holes: scarier than LiLo, galactic-sized Bieber or astrophysicists settling bets with encyclopedias.”

In science, “black hole” means something very specific; it’s not just a catch-all term for scary, life-sucking things like Congressional speeches or a trip to the DMV or Lindsay Lohan’s vagina.

A true black hole has certain characteristics. Unimaginable denseness and an irresistible gravitational pull, created by a star that’s given up its fire and collapsed into itself.

So, more like Lindsay Lohan’s career.

Cosmically speaking, it takes a special kind of star to form a black hole. It’s not like any old class K hayseed can fuse a few hydrogen atoms together and call itself a singularity. To go full-on black hole, you’ve got to be big. Like, Disney movie or Lollapalooza-ten-years-ago big. And then you have to violently implode — the violentlier, the better — and still keep enough mass to suck in all the matter and light and paparazzi for light years around.

Most stars never get the chance. Take our sun, for instance. It could appear in every edgy Sundance flick and Marvel comic blockbuster made in the next 5.4 billion years, and it still won’t go out as a black hole. Our sun is like the Larry the Cable Guy of stars. It’ll just hang around, getting fatter and occasionally shilling heartburn medicine, until it finally pops an aneurysm on the toilet.

Or engulfs the solar system in a baking-hot inferno. Whichever comes first.

Other stars are big enough to implode — that’s “supernova”, in star talk — but there’s basically nothing left afterward. These become neutron stars: reclusive, dim and not so interesting. Think Peewee Herman, or Tawny Kitaen. And then forget them again.

Black holes, though, are fascinating. It’s thought there’s a supermassive black hole at the center of our galaxy, and most others. Ours is four million times the mass of our sun, with the entire Milky Way orbiting it. It’s like the Justin Bieber of black holiness. And nearly as dense.

No one knows what happens inside a black hole, but space physicists are working on it. Stephen Hawking figured out that one kind of energy can escape a black hole, so they named “Hawking radiation” after him. Later, John Preskill won a bet with Hawking that this radiation would contain information about the stuff sucked into the hole previously.

(That’s some serious shit, winning a bet off the guy the thing was named for. Especially when it’s Stephen Hawking. He’s the smartest thing on four wheels since the Knight Industries Three Thousand.)

Recently, scientists argued about whether black holes are surrounded by a giant wall of fire — as if black holes weren’t badass enough already. One camp says “yes”, because monogamy of quantum entanglement, duh; the other says “nuh-uh”, because Einstein’s equivalence principle, obviously. They flung a bunch of math at each other, Hawking declared black holes dead (sort of, though most people agreed they weren’t) and the firewall finally (probably) went down. In flames. But no one knows for certain.

I vote we load Captain Bieber on a rocket, point it at galactic center, and let him find out for us. Maybe he can even get his own autograph on the way down the gravity well.

Image sources: Sun.org (black hole), Scary Movie 5 (Lohan), Sky and Telescope and NYPost (Bieber galaxy), John Preskill/CalTech (Hawking-Preskill bet)

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