Science Talk

From Carbon to the Cretaceous: Report from the American Geophysical Union Meeting

Scientific American editor Davide Castelvecchi reports from the annual meeting of the American Geophysical Union (AGU) in San Francisco. Subjects include the extinction of the dinosaurs and the Orbiting Carbon Observatory. And CNET Senior Associate Editor Michelle Thatcher gives us the lowdown on netbooks and tablet PCs. Plus, we'll test your knowledge about some recent science in the news. Web sites related to this episode include;

Podcast Transcription

Steve: Welcome to Science Talk, the weekly podcast of Scientific American; I'm Steve Mirsky. This week on the podcast we'll hear from Scientific American editor Davide Castelvecchi who is in San Francisco at the Annual Meeting of the American Geophysical Union; and CNET's Michelle Thatcher talks about netbooks and tablet PCs. Plus, we will test your knowledge about some recent science in the news. First up, Davide Castelvecchi. He joined the staff of Scientific American a couple of months ago and made his first road trip this week to the AGU meeting. We spoke the evening of December 18th.

Steve: Hi Davide, good to talk to you.

Castelvecchi: Hi Steve, great talking to you.

Steve: So first of all, let's talk just for a moment about what is the AGU meeting. What are the kinds of subjects they [that] get talked [about] at [the] American Geophysical Union conference?

Castelvecchi: It is, broadly speaking, earth sciences, I would say. But this means a lot of different things; it ranges from water management to space science; there were talks about other planets. So it's earth sciences in a very broad sense.

Steve: I know—we spoke a little earlier today and I know—that one of things that you learned about was interesting ideas about actually what wiped out the dinosaurs.

Castelvecchi: Yes, it's actually not a new theory, but it's a theory that is trying to make a comeback. There are researchers who claim that the generally accepted explanation for what wiped out the dinosaurs—which is the impact of a giant asteroid—is not enough or is not the right answer and that instead it was some gigantic volcanic eruption that caused the demise of the dinosaurs and of a lot of other species that were not dinosaurs.

Steve: So these volcanic eruptions—we've discussed them in Scientific American magazine before, that the so called Deccan traps—but there's a new wrinkle to what the particular researchers that you heard are proposing.

Castelvecchi: The idea is that the eruption spewed out not only lava, but also they created a sort of, kind of like a nuclear winter, which is an effect that we observe in volcanic eruptions nowadays; and the new twist is that these Deccan eruptions happened over a shorter time span than previously thought and close to the time when the dinosaurs actually disappeared. The new findings came from looking at the magnetism of the rocks, of the lava as it solidified, which kind of froze into place the picture of the direction of the magnetic field of the Earth when the eruptions happened. And because we get the magnetic fields very, very slowly, and you can tell how long the eruptions lasted because we see that this image of the magnetic field does not vary much during the eruption.

Steve: And so that the older ideas about why it wouldn't be the volcanic eruptions were based on the idea that while they were happening over hundreds of thousands of years, and you needed more of an immediate kind of—forgive the word impact because, you know, I am not talking about the asteroid impact in the [asteroid] sense—but these guys think that these volcanic eruptions were spewing out unbelievable amounts of material in like just a few years, right?

Castelvecchi: Yes, and we are talking about—you said it right—it is an unbelievable amount, which [is] something about millions of cubic kilometers. And just to give you an idea of what a million cubic kilometer[s] is, imagine taking the surface area of Texas and covering [it] with a mile worth of lava: That's about a million cubic kilometers of lava, and that would have happened over a period of a few years to a few decades according to these scientists.

Steve: Well, they do everything bigger in Texas, so...

Castelvecchi: Exactly.

Steve: So what's the general kind of reaction to their hypothesis? I mean this is a fascinating area because, you know, 40 years ago, the asteroid idea about the dinosaurs was completely unheard of. Then when it was proposed it was scoffed at and then it quickly became the accepted idea about what happened, and now we are starting to get some pushback about that, that looks interesting at least.

Castelvecchi: Yes, reportedly one of the proponents of the asteroid impact explanation is very skeptical, and I think that we will see how this plays out and it will be interesting to see how this plays out because there's probably still more research to be done.

Steve: Is that proponent Alvarez?

Castelvecchi: Yes, it was the father and son couple, and the son is still alive and was quoted as saying that he didn't believe it, and he doesn't buy the eruption explanation.

Steve: Right, I always get confused; I forget—there's Walter and Luis, and I forget which one is the father and which one is the son, but the son wrote a book called T Rex. and the Crater of Doom, and I highly recommend it to anybody who is interested in this field or who is interested in just reading a book by a researcher about their research. I think it is the most straightforward and entertaining example of a book by a scientist about their own research that I have ever read. So I highly recommend that. It's by Alvarez: T. Rex and the Crater of Doom. So anyway, so you got that interesting stuff going on there about what happened 65 million years ago, take a couple of weeks and tell me about, I know you heard a Lamont-Doherty Earth Observatory speaker; and what's he all about and who is he?

Castelvecchi: Yes. Wallace Broecker is from Columbia University's Lamont-Doherty Earth Observatory and he has traveled around the US and the other countries to look at lakes and to study the geological history of lakes, and the reason why he is doing this is to indirectly predict what global warming will do to rainfall. The prevailing wisdom, so to speak, is that with global warming, dry areas will get drier and rainy areas will get rainier, and then there will be more disastrous flood[s] and events like those; and what he has found however from traveling mostly to deserts and visiting what are now dry lakes or very small lakes in large basin[s], is that the truth may be a little bit more complicated, and, in fact, there may have been situations in which it went the other way around and warmer periods corresponded to rainier—to dry areas becoming less dry and to wet areas becoming drier.

Steve: And so that's just another wrinkle in the whole global warming–modeling scenario?

Castelvecchi: Yes. It seems that that the more researchers [are] looking to the local effects or regional effects of global warming, the more complicated the picture gets. It's not simply, you're turning up the thermostat everywhere, but there will be a lot of local variation on the scene.

Steve: Which is that may make it more difficult to get the idea across to the general public, if individual areas are going in different directions but, you know, if that's the reality, that's the reality.

Castelvecchi: Very definitely. One of the general themes that people have been sounding is that there will be winners and losers and so it might be difficult ethically and politically to take substantial action, because some people might be hesitant to forgo what would be good times for them from global warming.

Steve: Right: if you're o[w]n a golf course in Vermont, you pro-global warming. If you're o[w]n a ski resort in Vermont, maybe not so much. So, the orbiting carbon observatory, what's that?

Castelvecchi: That is a very interesting mission now, due to launch next year. It's a NASA satellite that will orbit the planet pole to pole and so it will scan—imagine the planet is rotating and the sunlight goes around and traces a meridian on the Earth and measures the amount of carbon dioxide in the atmosphere as it does so. And at each orbit the satellite will fly over a different meridian, because the Earth in the meantime has rotated, and so over a period of 16 days, it will map the concentration of CO2 over the entire planet.

Steve: With reasonably high resolution, too.

Castelvecchi: Yes, exactly. And that means that we want just to have data on the concentration of CO2 in the atmosphere on average, but we will have very local maps of CO2 and we will be able to know where the CO2 is coming from and where it is going.

Steve: Right, so you will be able to see very quickly effects of for examples deforestation.

Castelvecchi: This is a possibility and it will be interesting to see if, you know, like they say, a picture says more than a thousand words. If the effects of something like deforestation become visually obvious, it will be interesting to see if this will put more pressure on countries to limit deforestation, for example.

Steve: And I know you went to a talk; it's very interesting the idea that the entire atmosphere is kind of, the whole planet is kind of breathing, the atmosphere is expanding and contracting on a regular basis.

Castelvecchi: Yes, this was known before. It was known that as the sun itself rotates, the Earth is exposed to different amounts of ultraviolet rays which heat up the outer atmosphere, and just by thermal expansion or contraction when it becomes cooler, the atmosphere undergoes this breathing every 27 days which is the time it takes for the sun to do one full [turn] But these researchers have found strange breathing periods of fewer than 27 days and, in particular, for example, it seemed the atmosphere [was] growing at intervals of nine days, so, inflating and deflating about three [times] a month. Eventually, they've been able to attribute this also to variations in the sun's cycle, [which] comes from the fact that the corona of the sun, which is the sun's outer atmosphere, is not uniform; and there are features in it that form and persist sometimes for awhile. And what the researcher[s] compare this to is that, imagine you have three searchlights that rotate and they are at 120 degrees from each other, and for every full turn of the searchlights, you get three flashes.

Steve: Right, right.

Castelvecchi: So, for example, if the corona has three holes as he calls them—three gaps, as actually and hot areas—solar winds will change; the amount of solar wind that reaches Earth will change depending on whether the sun is pointing one of the searchlights at us or not.

Steve: And the solar wind is these highly energetic, ionized particles that are bombarding the atmosphere.

Castelvecchi: Yes, and so the amount of solar winds will go up and down instead of once every 27 days, and [in] that case it would go up and down three times over the same period.

Steve: And is there any kind of effect that the atmosphere's changing shape because of this is has on us or around things we do?

Castelvecchi: It actually has an effect on satellites, because low-orbit satellites are not completely out of the atmosphere. Here we are talking what happened to the atmosphere at an altitude of about 400 kilometers, and a lot of satellites don't fly much higher than that.

Steve: Right.

Castelvecchi: So they still are slow[ed] down by [a] little bit of drag from this very thin layer of the outer atmosphere, and the amount of slowing down depends on whether the atmosphere is swollen or deflated at that time.

Steve: Right. And you really need those satellites to be exactly where you think they are in order for them to function properly.

Castelvecchi: Exactly.

Steve: Very interesting stuff. You're going to be writing about some of the things you find out of this meeting.

Castelvecchi: I am hoping to have, all of this written up, yes.

Steve: Well this is great. Thanks a lot, Davide. Have a good trip.

Castelvecchi: Thank you. It was great talking.

Steve: For more on the AGU meetings just go to I was at a conference of the National Association of Science Writers a few weeks back and attended a talk by Michelle Thatcher from CNET about new products of interest to writers, but these products are really of interest to anyone listening to podcasts, too. So I got some more info from her after her talk.

Steve: Michelle for people who haven't seen them or heard of them, what are tablet PCs?

Thatcher: Tablet PCs are mobile computers that let you write directly on screen, so you can take handwritten notes. They are shipped with the special stylus, so you can take handwritten notes, draw diagrams, write formulas and often actually use handwriting recognition software to turn that into type, to [into] text.

Steve: And what are the pros and cons?

Thatcher: Well, I would say the biggest con is that they are a little bit expensive compared to a similarly equipped laptop. The pro is that you can, as I said before, taking [take] handwritten notes, which is huge if you are a scribbler or if you don't like the distracting sound of typing in meetings, and if you get a, what we call a, convertible tablet, it's essentially a laptop with a screen that twists around and folds over the keyboard so you can kind of have the best of both worlds with that. But again, it is going to be a little bit more expensive than just this standard laptop version.

Steve: Michelle, tell me about netbooks. I have seen them around a little bit, but it looks like they are becoming a little bit more popular, and there are a lot of pros to them and some cons. So first of all what is a netbook?

Thatcher: Well "netbook" is just the general term for this new class of notebooks that are a lot smaller than traditional notebooks; they are far more portable. They are usually between 2.5 and three pounds and they are extremely inexpensive, generally less than $500. So when we say netbook, that's, those are the two kind of key factors that we're talking about.

Steve: Key factors being the cheapness and the lightness. Because I remember back in 1998, I bought a Sony Vaio that was less than three pounds, but back then it cost about 1,700 bucks.

Thatcher: Yeah, it's actually really shocking to me, because when I first started reviewing laptops, I mean, this was the size of the ultraportable that everybody covered it, and they were easily more than $2,000. So now we are talking about the same form factor in a sub-$500 package.

Steve: Which is pretty amazing, but they are limited. You might be dissatisfied with it if you're trying to use it as your laptop. It's really a, kind of a, secondary device.

Thatcher: Yes absolutely, the smaller screen is a lot harder to work on full-time, I mean, these devices have anywhere from seven- to 10-inch-diagonal screens and except on the top end of that it's just going to be way too small for a full day's worth of work. And, of course, because it is smaller, it has a far more compact keyboard. Usually we are talking about 75 to 85 percent of the size of the full size keyboard, and so if you have large hands or just don't like the idea of adjusting how you type, then you would probably are not going to like the netbook.

Steve: And these devices do not have a disk drive.

Thatcher: As a rule they don't. I think incorporating a disk drive into that smaller form factor just is going to cost too much.

Steve: But they do have USB ports, so you could put an external disk drive on if you wanted to.

Thatcher: Yeah, they do. Most of them actually have two or three USB ports and they also have, you know, VGA so you can connect it to a monitor.

Steve: So basically, why would I want one of these things?

Thatcher: You could use it as a secondary computer. So you would want it if you have a desktop or if you have a larger laptop that you use for most of your main computing, but then you just want something to take with you when you go to conferences or if you go to the coffee shop and want to keep up with your e-mail or maybe just take some quick notes, just short, brief stints of typing—then a netbook might fit your needs as a secondary system.

Steve: And these things also have built-in Wi-Fi, so if I am at the Starbucks I can surf the Web.

Thatcher: Absolutely, yeah.

Steve: And still under 500 bucks with all that.

Thatcher: Yes, almost all. I mean, some of them are creeping up there. No ASUS Eee has a model of that's, you know, got a 10-inch screen and is topping the $550 mark. So at that point, you can almost buy a cheap larger laptop.

Steve: Right, but if I really want something that I can just throw in my backpack, and I won't even know it's there until I want to use it, this might be a good thing to use.

Thatcher: I think so, yeah.

Steve: So what [do] I not know is out there that's going to be coming out in the next year or two? I mean, obviously if I want to go really small, I can just get a Blackberry to do some of these kinds of things, but what is out there that might change my whole attitude about, "Well that's some [something] I [I've] got to have, because I can do so many different things on it and it's so easy to use"?

Thatcher: I don't know that there are any strong, well products on the horizon. There are little segments of the market that are going to amaze certain people. So for example, we are seeing a lot more laptops in the 16- and 18-inch screen size, which really gives you the proper 16-by-nine aspect ratio for displaying high-definition content. We are seeing, well coming out in the future, we expect in 2009—this is kind of inside-of-the-case development—we are expecting some more hybrid graphic solutions so that you can switch between a graphics card that borrows from the system RAM in order to render the graphics versus the graphics card that has its own RAM. So you can choose between battery life preservation with the former and some higher performance and better video display values with the latter.

Steve: Cool. So tell us: The entire presentation that I just sat through that you gave is going to be up on the Web by the time this interview is published; and people would be able to go view that where?

Thatcher: You can go to our gadget blog which is and click on the laptops category and you will find an article in there called "Best Laptops Providers" and that should be up quite soon.


Steve: Now it's time to play TOTALL....... Y BOGUS. Here are four science stories; only three are true. See if you know which story is TOTALL....... Y BOGUS.

Story number 1: A company is marketing an add-on to turn your iPod into a breathalyzer.

Story number 2: Researchers have found the world's oldest spiderweb.

Story number 3: There is a conspicuous lack of acorns in the east this year.

And story number 4: Alaska produced 20 percent of U.S. energy last year.

Time is up.

Story 1 is true. You can get an accessory that makes your iPod a breathalyzer. The iDrunk—no it's really called the iBreath—also doubles as an FM transmitter to send your favorite tunes to the radio of the car that you are not driving in your condition. For more go to

Story 2 is true. The spiderweb was found preserved in amber on an English beach two years ago. It's 140 –million-years-old, about 10 million years older than the previous record web.

And story 3 is true. The east coast is suffering from an acorn drought. Not to worry, however. Last year's acorn crop was huge, and there's often a linear following a bumper crop because the trees are basically worn out. Do be on the lookout though for hungry and aggressive squirrels.

All of which means that story 4, about Alaska producing 20 percent of U.S. energy last year, is TOTALL....... Y BOGUS. Here's John McCain during the campaign on Alaskan governor Sarah Palin's energy expertise:

John McCain: Energy, she knows more about energy than probably anyone else in the United States of America. She is the governor of the state that 20 percent of our, America's, energy supply comes from there.

Steve: Actually, Alaska was responsible for 14 percent of all the oil [emphasis] produced in the U.S. last year, but it's share of the total energy produced in the country was 3.5 percent; that's according to the U.S. Energy Information Administration. Of, the energy consumed in the U.S., Alaska accounted for 2.4 percent. McCain got the 20 percent figure from Palin. Oddly, President-elect Obama chose not to nominate Palin for energy secretary despite McCain's claims of her knowledge. Instead this week, he went with Steve Chu, director of the Berkeley National Lab and a Nobel laureate in physics. While he may not be the energy expert that Palin is, Chu probably isn't under the impression that a joule is a diamond, an erg is when you have a big hankerin' to do something and a Btu is great on toast with mayo.

Well that's it for this edition of Scientific American's Science Talk. Visit for all the latest science news, videos and slide shows. For Science Talk, I'm Steve Mirsky. Thanks for clicking on us.

Science Talk is a weekly podcast, subscribe here: RSS | iTunes

Scientific American editor Davide Castelvecchi reports from the annual meeting of the American Geophysical Union (AGU) in San Francisco. Subjects include the extinction of the dinosaurs and the Orbiting Carbon Observatory. And CNET Senior Associate Editor Michelle Thatcher gives us the lowdown on netbooks and tablet PCs. Plus, we'll test your knowledge about some recent science in the news. Web sites related to this episode include;

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