SGU Episode 345
| SGU Episode 345 |
|---|
| 25th February 2012 |
 |
| (brief caption for the episode icon) |
| Skeptical Rogues |
| S: Steven Novella |
B: Bob Novella |
R: Rebecca Watson |
J: Jay Novella |
E: Evan Bernstein |
| Guests |
FC: Fraser Cain |
PG: Pamela Gay |
| Quote of the Week |
Experience is a hard teacher because she gives the test first, the lesson afterwards. |
Vernon Sanders Law |
| Links |
| Download Podcast |
| SGU Podcast archive |
| Forum Discussion |
Introduction
You're listening to the Skeptics' Guide to the Universe, your escape to reality.
S: Hello and welcome to the Skeptics' Guide to the Universe. Today is Wednesday, February 22, 2012 and this is your host Steven Novella. Joining me this week are Bob Novella..
B: Hey everybody.
S: Rebecca Watson.
R: Hello everyone.
S: Jay Novella.
J: Hey guys.
S: And Even Bernstein.
E: Hello everyone. How is everyone tonight?
S: Great. How's everyone doing?
R: Super.
B: Pretty good.
J: Fabulously.
E: Hanging in there. Not bad.
This Day in Skepticism (0:31)
February 25, 1866 - Discovery of the Calaveras Skull
R: You know, it's a very exciting day today, today being February the 25th. This is the anniversary of the discovery of the Calaveras Skull, which was found in 1866.
E: Not one of those crystal skulls, is it?
R: No. This was a real skull, uh, you know it's a real skull just by the name, because as our Spanish speakers know, Calaveras Skull means Skull Skull. So.. that's handy.
S: Skull skull.
E: Skull skull.
R: Yeah the Calaveras Skull is one of the great archaeological hoaxes of the past couple hundred years. What happened was in 1866, on February 25th, some miners claimed that they found a human skull beneath a layer of lava very deep in the earth, so they handed it over to some geologists. It eventually made its way into the hands of Josiah Whitney, who was a professor of Geology at Harvard University and the state Geologist of California. I'm not exactly sure if that's a position that still exists, but he held it back then. And Whitney..
E: That's a hell of a commute..
R: ..made an announcement that it was a genuine skull, and so at the time it was announced as the oldest possible human being that had ever been found. It was immediately met with quite a bit of skepticism, (B: Yay!) mostly because the skull happened to look exactly like human skulls do today. So it was eventually embraced by Creationists, because Creationists used it as some evidence that humans had existed for millions of years without having ever changed, so the Old Earth-style Creationists...
E: Yeah you find a skull that deep and...
S: Yeah it was technically Pliocene strata which would make it between 5.3 and 2.5 million years before present, which of course is a lot longer than Homo sapiens have been around, and a lot longer than Homo sapiens have been in North America.
B: Yeah, so that would present a problem..
R: It wasn't until though, a good 30 years later that an archaeologist from the Smithsonian named William Holmes decided to investigate it more thoroughly. There had already been these rumblings about people not believing it was true, and also rumors that the miners had deliberately set it up as a hoax. So this one particular archaeologist decided to look into it and he performed some tests, he found that to not many people's shock, it was in fact a much more recent skull than had been suggested. In fact, it was a skull of a Native American. It matched, at least, it matched the skull of a Native American and it would have possibly been about 1,000 years old, as opposed to millions of years old.
E: Wow. 1/6th the age of the earth.
R: (Laughs) Exactly. He also went back and talked to some of the friends of the miners. The miners who had discovered it were dead, unfortunately, but he was able to talk to many other people who confirmed that these guys had set this up as a deliberate hoax on one particular scientist who almost didn't fall for it. It was apparently first turned over to a guy named William Jones, who is a physician and a natural history buff, and he found cobwebs inside it, and tossed it out into the street, so the story goes. But then he thought twice about it, went back, picked it up, gave it a little more consideration, thought it might be genuine, turned it over to Whitney, and Whitney took it as the real thing.
S: There are remarkable similarities between this story and the story of Piltdown man.
B: Ahh yeah.
S: One is that the skull was taken as confirmation of the beliefs at the time specifically of this guy, Josiah Whitney believed that humans were much more ancient than other scientists at the time believed, and he thought they coexisted with mastodons and so he took this skull as confirmation of his pet theory. And that motivated him highly to accept it as real. The second similarity is that it was really, it was very quickly, I think more quickly than Piltdown, thought to be a hoax. It was not generally accepted as real, but still it took 30 years. Like with Piltdown, there was a long delay before definitive testing of the fossil itself.
J: Why did they wait so long?
S: I don't know. Do you know, by the way..
B: Time was slower back then..
S: ..do you know what test they used to date it? The fluorine absorption dating. Fluorine absorption.
E: Gosh I haven't heard of that in..
R: And was the first time that had been done, I think, or one of the first times that had been done.
S: Yeah so that was probably why they waited, because they didn't have a method for testing it. Very quickly, fluorine absorption uses the absorption of fluoride from groundwater into bones that are in the earth, so it tells you how long they've been in that soil. But there's no standard rate, so you need to compare it to other bones in the same soil that you date by some other means. Or you could only give relative dating. It's older than this bone, or not as old as that bone. But if you have any kind of reference, then you could put it in between specific dates. Certainly though, it's an accurate enough method to give you three orders of magnitude. You know, the difference between 1000 years and several million years. That's an easy determination to make, even with the fluorine absorption dating.
R: And it was backed up by carbon dating in 1992, that suggests that it was about 1000 years old.
S: There you go.
R: Yeah, and it wasn't just Whitney who was going based on.. who was grasping a hold of this because of what he believed in. As recently as 2008, Walter Brown.. Walt Brown's book In the Beginning: Compelling Evidence for Creation and the Flood cited this as evidence in favor of Creationism.
S: I'm shocked. A Creationist who's latching on to flimsy evidence because it happens to support their world view?
R: It's stunning.
E: Funny that book didn't make it to the New York Times' Bestseller List..
J: And I'm sure that they retracted that after it was proven false, right?
R: You mean after it was proven false 100 years prior to the publishing of that book?
(Laughter)
R: Yeah, no.
News Items
Tiny Lizards (7:31)
S: Well, have you guys seen the tiny lizards of Madagascar?
R: Yes..
J: They're awesome!
B: They're adorable!
E: I want one.
S: They're so tiny.
J: So easy to smuggle, too.
S: Yeah I wonder if they would become popular pets. So scientists have discovered..
B: Too tiny.
S: .. a species or several species actually, of chameleons that are among, it says, among the world's tiniest lizards. I guess they're not the smallest.
J: So Steve, do they think those chameleons are pretending to be that small?
S: (Laughs) It's just camouflage? It's all an illusion?
E: They're actually huge.
S: One species, Brookesia micra reaches a maximum length of just 29 mm. That's teeny tiny. There's a picture we'll link to of the guy on the head of a match. It's standing on somebody's thumb, and it's tiny, it's teeny tiny. They're very cute. What's interesting is that this is probably a manifestation of island dwarfism, which is a very interesting phenomenon. I know we've talked about it a little bit before. Madagascar in general has very small fauna. You guys have probably seen the movie Madagascar, right? Even though it was a cartoon. All the animals are very small compared to say, African animals. And this has been an observed phenomenon and a lot of speculation about it and study and research trying to figure out why does there appear to be this tendency for large animals to become smaller when they migrate to an island. There's also an observation called island gigantism where some species, particularly small species, may become larger. Where relatively large species become smaller.
E: It depends on what else is on the island.
S: That's part of it. So part of it may be driven by competition. Herbivores may become smaller because there's just less food available and smaller animals are better able to survive eras or periods of time where there's a food scarcity, and so every time you get to any kind of food crisis, it's all the small creatures that survive. And then predators become smaller in order to adapt to the smaller prey. A large predator can't survive on small small prey. They have to become small in order to.. for them to have enough food.
B: Yeah well that makes sense, but you also mentioned that some animals get bigger though..
S: Yeah so some small animals.. like there are giant rats on certain islands.. right?
B: Cool.
J: Yeah like Manhattan Island.
S: Yeah Homo floresiensis is a dwarf human species found on the island of Flores, but on the same island there were also fossils at the same time of giant rats. So imagine a hobbit-sized person with a dog-sized rat.
B: Really, dogs? What kind of dog are we talking about?
S: I know.. dog-sized is like.. there is a huge range.
B: Chihuahua? St. Bernard?
E: World's smallest dog.
S: Head to body , 41 to 45 cm.
J: So what you're saying is that there were small people riding giant dog-sized rats.
S: Yeah, basically. So in this case, island dwarfism is really just a subset of so-called insular dwarfism, so it's just a result of isolation of a being restricted to a very small distribution, geographical distribution. But that doesn't have to be an island. It could be isolation due to a desert, if you're in an oasis in a desert for example, you're trapped in a very small area. That also engenders dwarfism. So what they think happened here was that you already had dwarf chameleons on Madagascar. And then among those dwarf chameleons, some populations then became isolated in little parts of the island and then you had insular dwarfism among the dwarf chameleons on Madagascar, and they become micro-chameleons. Really, really tiny.
R: This is what I wanted to major in when I was in 6th grade.
S: Yeah..
E: Teeny, tiny animals?
R: Tiny Biology. I started to go into Microbiology and then I realized that it was not cute enough.
E: Whoa.. too small.
J: I have some tiny biology.
R: I know you do.
S: Okay, well let's move on.
J: Wait a second. These would be very easy pets to have. They wouldn't eat much, there's not much poop to clean up.
S: Yeah you could have a terrarium, right, one of those giant fish bowls, and that would be a massive forest to them. You could have 20 of them in there, that'd be cool.
B: If you could find them.
S: Now the thing is, during the day, they hide in the ground leaves, the leaves on the ground. And then at night they then climb up the trees to feed and the scientists had to stake out likely places where they would emerge at night time and then catch them in the light. But during the day they're hidden, which is part of the advantage of being small, that you can hide really well.
Missing Dark Matter (12:37)
S: Alright Bob, tell us about how scientists have found the missing dark matter. Isn't that a little redundant, missing dark matter?
B: They're calling it bright matter now. Alright, this is the coolest dark matter news I've seen in a long time. Japanese scientists have taken observational data of galaxies and combined that with simulations that they've done on computers to show that galaxies aren't distinct island universes but could all be connected by a vast web of dark matter that fills intergalactic space. Researchers at the University of Tokyo's Institute for Physics and Mathematics of the Universe is the name of this place, and Nagoya University may have solved one of the long-standing mysteries of dark matter with this news. Now dark matter and its partner dark energy, of course, constitute most of the matter and energy of the known universe, but scientists and I are very frustrated because we don't know even the most fundamental things about them. We do know some things of course, we do know that there is some type of new matter out there that is utterly undetectable except for its gravitational influence. We know that it constitutes a big chunk of the known matter of the universe.. about 22%. Well.. what we thought was the entire universe previously, really is only 4.. a paltry 4.5% so it's really tiny. But one of the big mysteries about this is not only what the hell it is.. which of course we still aren't sure.. but where the hell it is. Now this is the mystery that now looks like these guys may have solved. And it all starts with gravitational lensing. I'm sure you guys have heard about gravitational lenses?
E: Oh yes.
B: Since gravity bends light, if there happens to be a galaxy between me and you, the galaxy will distort the path of the light, changing how you look to me and where you appear to be. So that's essentially what's happening. This phenomenon, it's a natural byproduct of Einstein's General Theory of Relativity. Hey, did you guys know, by the way, that Einstein wasn't the first person to verbalize the idea of gravitational lensing?
E: He made it famous but uh..
B: A physicist named Orest Khvolson wrote about it 12 years before Einstein did, I thought that was an interesting fact.
S: Well also, Bob, classical physics also predicts and produces gravitational lensing, just not as much as relativistic theory, as the theory of general relativity.
B: Okay, I didn't know that it actually made solid predictions about it. So if the mass is big enough and symmetrical enough, you can even appear.. the object on the other side of this gravitational source can even appear like a ring of light around the galaxy, or whatever the gravitational source is. And they call these.. I've heard them referred to as Einstein rings, and also I was kind of happy to find out that some people call them Khvolson rings as well, in honor of this guy who first wrote about this idea. The problem is that this is a really minuscule effet. Even if we're talking about a huge galaxy, it's going to be really difficult if not impossible, just by using a galaxy to really see and get a handle on this lensing. So.. but it's not a minuscule effect, however, if you have 24 million galaxies. And this is exactly what the Sloan Digital Sky Survey.. which I think we've talked about before.. this is what this survey has given researchers in its 12 years of mapping the night sky and making its data freely available to anyone online. Bottom line is that with so many galaxies surveyed in high enough detail, what you can then do with that is examine the subtle effects of this gravitational lensing, but on a really huge scale. And the thing is that these scientists weren't looking for a lensing effect caused by galaxies, they were looking for this lensing caused by the dark matter itself that might be around or near the galaxies. Therefore, if you look at the distortion caused by the lensing, you can then infer the density and the distribution of the mass that would have to cause that. The result then is a dark matter density distribution over a distance of about 100 million light years from the center of all those galaxies. So with all this data, they then plugged it into a computer simulation to flesh it out and what they found.. it was to me, at least visually, was the most extraordinary discovery of all.. the dark matter would have to extend from galaxy to galaxy in such a way that they're all connected in this vast web of dark matter.
J: So Bob, are you saying that the aggregate of all of those galaxies is actually forming one gigantic lens?
B: No, no. What I'm saying is that if you looked at all these galaxies and everything around the galaxies of course, and you look at the lensing, the gravitational lensing that's happening, the only way to explain the amount of gravitational lensing that you're seeing would have to be dark matter that extends, that fills intergalactic space and actually even connects galaxy to galaxy. It's really cool to think of all these galaxies, they're really connected, they're actually.. the outskirts of the galaxies.. it extends so far that it actually connects up from galaxy to galaxy. So if these guys are right.. and remember a lot of this is based on a computer simulation, but it's based on really solid data, and it looks pretty good. So the mystery of where dark matter is, which was a mystery, they really weren't sure where all of this stuff was. It looks like it was solved. It's in intergalactic space and connecting everything up. Of course now one of the main things we still have to figure out is what the hell that stuff is. But I thought this was a really interesting story.
S: Bob, one thing I'm confused about is just in my limited understanding of this issue is I thought that the purpose of hypothesizing the existence of dark matter in the first place was to explain galactic rotation. It was extra gravity within galaxies.. then they must have figured out that there is also missing matter between galaxies?
B: Yeah, the matter, the dark matter just within and nearby the galaxy is not enough to account for all this gravitational lensing that they saw.
S: So the "missing dark matter" was that a response to the observation of this lensing phenomenon, or the lensing just helped locate the dark matter but we knew there was missing dark matter for some other reason? Because that's what I'm missing. If that's true, what's the other reason?
B: I see.
S: How did we know there was missing dark matter? And that the amount that would need to exist within galaxies in order to account for galactic rotation wasn't enough, enough for what?
B: Yeah if they didn't have the lensing, the massive lensing effects, then how did they even know to think, "well there's gotta be more dark matter somewhere."
S: Yeah.
B: Yeah I'm not sure. I don't know the answer to that question, that's a good one.
S: Okay. Dark matter is endlessly fascinating. Imagine how fascinating it's going to be when we actually figure out what the hell it is.
B: Ha ha ha.
Anti-Climate Gate
S: Let's come back down to earth a little bit.