What a strange word is multiverse

There is a word for everything that exists, for the sum total of all the atoms, mice, cities, forests, planets, galaxies, and galactic superclusters that exist, have ever existed, or will ever exist. That word is “universe”. It used to be “world”, but then the totality of everything got too big for the world and a new word was needed. It’s possible that a new word is needed again.

The word, if it is indeed needed, is “multiverse”. [1] It sounds like it means multiple totalities of everything, which wouldn’t make any sense. It doesn’t quite mean that; like world before it, the concept of a universe has become too small to contain everything. The world is what contains everything that we encounter, and — for almost all of us — our lives, beginning to end. It is also a ball of rock hurtling through empty space as it orbits the sun. There are other balls of rock hurtling through empty space orbiting the sun. There are even more balls of rock hurtling through space orbiting other suns. A world still contains us, but is too small to contain everything.

Our universe is a collection of stuff — mostly Dark Energy with some Dark Matter and a tiny bit of ‘ordinary’ matter thrown in for seasoning. The latter two are organized into web-like networks of galactic superclusters. There are also photons (light), neutrinos, black holes, and — very, very, very, very occasionally — a human. (There is some overlap in these categories.) In addition to all being in roughly the same place (give or take a few tens of billions of light-years), all of these things obey the same laws of physics.

So once upon a time, we took our previous concept of world and applied it to all the balls of rock flying through space. We did the same thing with “sun”. It was the ball of fire in the sky, the source of light and energy and life for all things. Our sun still is that, but any ball of gas shining through fusion and with planets orbiting it can now also be a sun.

And just like that we can generalize the word universe as a region, or perhaps bubble, of space governed by a particular version of what we call the laws of physics. In other universes the laws might be slightly different — electric charges might attract and repel each other with a strength that is a bit stronger or a bit weaker; or protons might weigh slightly more or spacetime might bend more easily. Or, the laws might be very different. There might be a completely new force; say something like electromagnetism that only acts on electrons and not protons. Each universe would behave slightly, or drastically, different. Most would collapse a tiny fraction of a second after forming. Some will expand so fast galaxies and stars and planets will never have time to form. A tiny few will have the right conditions to support life.

Now, what’s weird is not that we can imagine such universes, but that there is a reasonable way they could all exist, and exist within the same “totality of everything” that we do, separated not by some mystical dimensional barrier, but simply by ordinary space. Incomprehensibly large tracts of space, but ordinary space none-the-less.

This is the crux of the multiverse theory, which has become quite popular recently. Through a string of apparently disconnected theoretical developments this picture of bubble universes spread throughout a much more vast space has gone from pure fantasy to quite conceivably real. (Note the qualifier in the previous sentence. Many of the pieces required by this theory have not been empirically verified.)

[1] I’d nominate “cosmos” in memory of Carl Sagan, but multiverse seems to have won for now.

Non-academic scientists

It sounds like an oxymoron to a lot of academics, but there are a lot of non-academic scientists. In fact, since there are far more degrees awarded than jobs available, then the majority of people with advanced science degrees must work outside of academia.

Over at Uncertain Principles, Chad Orzel has launched the Project for Non-Academic Science, where he’ll be interviewing people with jobs outside the academic rat-race. The first few posts are up, with more coming over the next few weeks.

Quantum unicorns and antimatter

An emotion is running high as around the world physicists are bracing themselves in anticipation of one of the biggest events of the decade. That emotion is dread, and what they’re bracing themselves against is an enormous flux of annoying questions, because the event is the release of the the movie version of Dan Brown’s Angels and Demons.

The worst part is that, no matter how bad the movie is, we’ll have to see it just to understand the questions.

Fortunately for me Luke McKinney has put together a run-down of the problems with the story at The Daily Galaxy.

The fact that antimatter can create huge explosions is accurate, a rarity in Dan Brown novels…The problem is, if your terrorist organisation has a kilogram of antimatter you’re invincible anyway – because you can fly past security checkpoints on your quantum unicorns and hypnotize targets using The Force.

Read the rest to find out how re-evolving dinosaurs fit in.

Two cultures and a bonk

Chirs Mooney and Sheril Kirshenbaum, among others, are organizing a conference on “The Two Cultures in the 21st Century”, in honor of the 50th anniversary of C.P. Snow’s famous lecture of (roughly) the same name. The two cultures in question are the sciences and the humanities. Snow began an exploration of why there is such a gulf in thinking between people with those backgrounds and what the consequences are. That’s not nearly as academic as it looks: poverty and social policy was the example he chose. Today that’s just as much an issue and we can add things like climate change to the list.

The conference should be fascinating, with speakers like E.O. Wilson, Ann Druyan, and Carl Zimmer. I’ll be there, and hopefully live-blogging.

In the meantime, Chris and Sheril are running a couple book readings to prepare. Chris is hosting a discussion of the “Two Cultures” essay itself. Sheril is leading one on Bonk, Mary Roach’s tour through the science of sex. Both should be a lot of fun.

Statistics and doctors

Here’s a paragraph from a recent Scientific American article on the interpretation of statistics:

…only about one out of every 10 women who test positive in screening actually has breast cancer. The other nine are falsely alarmed. Prior to training, most (60 percent) of the gynecologists answered 90 percent or 81 percent [chance that the woman actually has cancer], thus grossly overestimating the probability of cancer. Only 21 percent of physicians picked the best answer—one out of 10.

The context here is false positives; the chance that the test will indicate a problem even if there is no cancer. The false positive rate is small, but since mammograms are recommended as a routine screen there are vastly more healthy patients getting them than ones with cancer. The result is that even with a positive test, there’s only a 1 in 10 chance that the patient has cancer. (Which is, of course, why further tests are done at that point.) The same reasoning applies to any screening procedure.

Now for the scary part: read that paragraph again. It’s not just that only 21% of physicians could pick out the right answer; these were gynecologists being asked about one of the most common tests they perform. The fact that statistics are badly understood is routine, but professionals misunderstanding one of the central statistics of their discipline is both surprising and horrifying.

The authors of the Scientific American article advocate a different way of presenting the statistics. So instead of saying “1% of women have breast cancer”, they would recommend “10 out of every 1000 women have breast cancer”. This apparently had good results.

After learning to translate conditional probabilities into natural frequencies, 87 percent of the gynecologists understood that one in 10 is the best answer.

I’m not sure if I should be happy about this, or incredibly sad that 13% still couldn’t.

Emily Levine

Blending philosophy, science, and a rare medical condition is a tricky proposition. Doing it in a way that is both engaging and hilarious takes extraordinary skill. Luckily for the rest of us, Emily Levine has that skill. She’s currently running a one woman show in New York, “Emily at the Edge of Chaos”, which unfortunately closes this weekend. (There’s a review at Talking Science, so you can see what you missed.)

The point of all this, though, is that her TED talk from 2002 is now online, and it’s just as incredible (if a bit shorter).

Arp 274 Wins!

I know you were all on the edge of your seat to find out the winner of Survivor: Universe. It was a long, drawn-out drama-fest, but in the end it was everyone’s favorite galaxy group Arp 274! I shudder to think about the riot that would have accompanied an NGC 4289 upset.

The NASA site has the larger image and a video about how it was made.

How long does it take to heat a spherical cow?

ZapperZ points to this outreach question from the APS:

How long would you have to yell to heat a cup of coffee?

It’s a neat question. The idea is that sound transfers energy. That energy will hit the coffee and dissipate as heat, so by yelling at a cup of coffee you could heat it up. Except of course that you can’t. The coffee will be losing heat as you yell at it, and will cool from hot to room-temperature in a couple hours. And yet, the APS site gives this answer:

In other words to heat up a quarter liter of coffee 50 C it would take: 1 year, 7 months, 26 days, 20 hours, 26 minutes and 40 seconds

How did they get that? The answer, of course, is that they used a spherical cow.

A real stand-up scientist

I talked about how Neil deGrasse Tyson gave a performance that was close to a stand-up act. That isn’t quite what he was doing; he gave a very funny lecture about his experience with the Pluto controversy. There are, however, a few people around who do a science-fueled stand-up act.

Brian Malow is a San Francisco based comic who does “Full spectrum, high-energy comedy”. Here’s his best-of video:

NASA hearts voting

Having people vote on the names of missions seems to be the thing to do at NASA outreach.

There was the vote to name the next module on the International Space Sation, predictably bombed by Stephen Colbert. (Althought NASA may have given themselves a way out. I’d be more upset if I wasn’t so happy that Serenity was leading.)

Now there’s a vote to name the next Mars rover (via. PhysioProf). The names are a bit… flat. Vision. Pursuit. Journey. Yeah, yeah, they were sent in by schoolkids, but the final 9 were selected by NASA themselves; there must have been some good suggestions. Ask thousands of second through twelfth grades for suggesions; you’re going to get something better than “Vision”.

The best suggestion, though, was “Amelia”. Because there’s nothing at all problematic about naming a Mars mission after someone who vanished without a trace.

(Actually, you can see why they need thsee votes for names by looking at the NASA Mission Madness, where you vote for your favorite missions like X-43 and NB-52. Sigh.)