Sometimes, the images from the Cassini Saturn probe are so cool it’s tempting just to post them and say, "Look at THAT!"

See what I mean? [Click to gigantesenate.]

But of course, I can’t just leave it at that. This image, taken on January 4, 2012, is a bit different than most. Sure, we see Saturn’s magnificent rings, nearly edge on from this perspective. And we’ve seen this icy moon Enceladus many, many times (see Related Posts below for tons more pictures). Look at the bottom of the moon: see those fuzzy streaks? Those are geysers of water spewing from cracks in the moon’s south pole! Cassini has been studying them intently ever since they were discovered; they are proof that liquid water exists under the surface of Enceladus, though it’s still being argued over whether it’s in pockets, like lakes, or the whole moon has an ocean of water under the surface.

Despite all that, I keep getting drawn to the crescent shape itself. We can never see that from Earth. Saturn is much farther out from the Sun than we are, and geometry demands that from home we always see these worlds nearly fully lit by the Sun. The only way to see them like this is to go there.

But also, that giant circular feature is really interesting. It’s big, maybe 200 km (over 100 miles) across, and a bit darker than the surrounding surface. I tried locating it on an atlas of Enceladus, but it wasn’t obvious at all. I thought it might be an impact basin, but a little scrounging online led me to a paper by Cassini imaging team leader Carolyn Porco, which says there are no large impact basins on Enceladus! So what is it?

Well, why not go to Dr. Porco herself? I sent her a note, and she kindly replied. That region is called Diyar Planitia, and it stands out among the surrounding terrain because it’s much smoother. It does have narrow surface features, but they’re too small to be seen at this resolution. At the low angle at which we’re seeing it here, it looks a little bit darker than the rougher terrain around it, so it’s easier to see (which is why on an atlas it’s harder to find). It is roughly circular, but that may simply be coincidence. Enceladus has been massively resurfaced, with some areas much older than others, due to various forces under the surface — looking this all up I learned a new one, called diapirism, where lower density material underneath higher density material can rise up and break through. That’s one process that’s helped change the surface of Enceladus over the eons.

That’s pretty nifty. And think about that! Today I learned of what is to me a new region of the solar system, one that has an interesting and complicated history, molded by vast forces over long-stretched times, one of which was also new to me. How wonderful to get all that from what’s otherwise just a pretty picture!

But of course, in science, there’s no such thing as just a pretty picture. Science is a tapestry, a vast complex fabric interwoven with countless threads. Each of those threads is amazing, each important, and each leads to another. And that’s where the true beauty of science lies.

I caught this video on Geekologie, and it made me laugh. This is a brilliant idea: a woman put a camera on a hula hoop, and then, well, hula’ed:

[WARNING: some folks might feel ill watching this. I will not be blamed if you have to wipe vomit off your keyboard.]

[Note: at the end of the video there are links to other videos like it.]

I found this fascinating. For one thing, the motion is slower than I would’ve expected. I suspect that may be due to an illusion when you watch from the outside as a hula hoop being used; humans are notoriously poor at judging rotating reference frames. After all people, still try to argue with me that centrifugal force isn’t real, when it it quite clearly is.

Even more amazing to me was that I didn’t get ill watching that video. I tend to get a seasick on a kid’s swing or when reading in a car, so the fact I was fine watching this is weird. But I have pretty good 3D spatial reasoning, and have a lot of practice swapping reference frames — trying to figure out when the Moon rises, what configuration planets are in, and how to point a telescope give you a lot of practice there — so maybe that helped. Beats me.

But I wonder what other weird change-of-frames would benefit from using this camera technique? That might make a fun series of videos.

I love science. OK, duh, but I really do. And when I go on vacation, I can’t help but see science everywhere, and in every case it makes the trip more fun for me. Seeing local geology, biology, how the stars might look different at a different latitude… it adds to the vacations, makes it better.

That’s why my wife and I started a company called Science Getaways. We figured there are lots of other folks out there like us who would really enjoy taking a vacation that has bonus science added in. Our first planned trip is to a gorgeous Colorado dude ranch called C Lazy U. Besides the usual amenities of such a place — horseback riding, great food, spectacular views of the Rocky Mountains — we’re adding SCIENCE! And scientists: we have a geologist, a biologist, and an astronomer — hey, me! — who will be on hand to give talks about the local nature scene, and then we’ll take hikes to put that new-found knowledge to practical use. I’ll be running a stargazing session every evening with my new 8" Celestron telescope, and I’m hoping to do some solar observing during the day as well.

IMPORTANT NOTE: We’ve negotiated a special rate — the price we’re offering is actually less than the usual ranch rate. We’re hoping to have the entire ranch for our group, but if we don’t have enough reservations by March 1 we can’t guarantee it. Space is limited, so please book now if you plan to come.

By the way, we’re also on Facebook and Google+ if you’d like to add us.

I hope to see lots of BABloggees there!

Today in America is our most revered holiday: the Superbowl. I am not particularly invested in either team — I had to look up who’s playing, to be honest — but there is something about the game I like: science! Yes, science, of which there is plenty to be had during any sporting event. You just have to look for it.

Last year, during the big game, I tweeted a series of science facts relating to football, and, when the game was over, collected them into a blog post.

I thought it would be fun do it again — this time, I’ll use the hashtag #Sciperbowl — but this year, instead of waiting to collect them, I’ll simply update this post as I add them. That way you don’t have to wait until the end of the game to see them all.

So sit back on your recliner, keep one hand in a bag of chips and another on the refresh button. Let’s see how to really enjoy this game! I’ll start the tweets and start updating this post at the start of the game.

First Quarter

1) Realistically, a football is not a ball. It’s more of a prolate spheroid.

2) Football pads work by absorbing impact as well as spreading it out over a larger area.

3) Pads lower the force of impact by lengthening the time of the collision.

4) Pressure = Force/Area, so increasing the area of the impact reduces pressure and therefore injury.

5) Every time a football is thrown, it’s briefly in orbit… but the Earth gets in the way.

Second Quarter

NOTE: The following info uses air (not ground) speed and neglects air resistance. [Note: the math on these next ones can be found online, for example at the CSU San Bernadino website.]

6) To be thrown 100 yards, a football should leave the quarterback’s hand at a 45 degree angle at 70 mph.

7) The ground speed of that throw is about 50 mph.

8) A ball thrown like that will reach a max height of about 80 feet.

9) A 100 yard throw like that will take about 4.5 seconds to go up and come back down.

Halftime

10) Halftime for the Universe was 6.86 billion years ago (+/- .12 billion).

Third Quarter

11) Because the Moon has 1/6 the Earth’s gravity, lunar football would be pretty different.

12) On the Moon, a football thrown at 70 mph would go 600 yards, take 27 seconds, and reach 500 feet high.

13) Throw a lunar football at 28 mph to get it 100 yards downfield. It’ll take 11 seconds & get 80 feet high.

14) All those throws assumed a 45 degree angle. At higher and lower angles, the ball must be thrown faster.

15) Want the ball to go into Earth orbit? You’ll have to throw it at 5 miles per second.

16) In a black hole, it doesn’t matter how hard you throw the ball. It’s not getting out.

Fourth Quarter

17) During a 4 hour game, the Earth rotates 60 degrees.

18) During a 4 hour game, the Earth spins a total of 3200 miles at the latitude of Indianapolis.

19) During a 4 hour game, the Moon travels over 9000 miles around the Earth.

20) During a 4 hour game, the New Horizons Pluto probe travels 130,000 miles farther from the Sun.

21) Since the starting whistle, the Sun’s moved 2 million miles in its orbit around the center of the galaxy.

That’s it! And congrats to whichever team won!

Football picture from Elvert Barnes’ Flick photostream.

[Note: Every week I hold a live video chat on Google+ where I answer questions from readers. I call it Q&BA, and when I get a question that stands alone, I'll make it its own video. ]

Every now and again, I hear this urban legend that pound for pound, the human body is actually hotter (or has more energy) than the Sun. I got this question in a recent Q&BA video chat session, so I tackled it. The answer is pretty interesting, and depends on how you ask the question!

I actually wrote about this legend on the blog a while back, and I show all the math. I really like this question, since it has a straightforward answer that makes it seem wrong, but then if you look at it more carefully the answer is a little trickier. And even in the video and that other post, it’s not really a complete answer; if you read the comments on the post you’ll see people arguing over it.

That’s really the best kind of question: the ones that keep on going! There’s always more stuff to figure out.

Visit the Q&BA Archive to see more videos like this one!

Over the years I have pointed out the fallacious arguments of climate change deniers when they attack legitimate climatologists like James Hansen and Michael Mann. This is, of course, like kicking at a bee hive, and whenever I do the comments section of my posts fill with lots of angry buzzing.

But now, for what I think is the first time, I find myself the target of an attack. And I have to admit, I welcome it: it’s a textbook case of denialist sleight of hand, of distraction, distortion, error, and misdirection.

Stick around for all of this. It’ll be… interesting.

Our story so far

OK, first, here’s the scoop: a few days ago, I wrote a blog post taking apart two intellectually bankrupt climate change denial articles, one in the Wall Street Journal, and the other in the UK’s Daily Mail. Both were claiming that global warming appears to have stopped in the past few years, a claim which is trivially easy to show wrong. In fact, I linked to two articles doing just that: one at Skeptical Science, and another I myself wrote. Finding actual scientists destroying that claim is not hard at all; those two links have many more links therein.

In my post about the WSJ and DM, I included a graph. It pretty clearly shows temperatures rising from 1973 to the present. And this is where the fun begins.

That’s the plot. It’s from a recent, independent study done at Berkeley, and represents actual, measured, data. Just to be clear, those points are from weather stations across the globe, and the method used to collect and analyze those measurements is described by the Berkeley team themselves (PDF). With me so far?

Apparently, William Briggs is not with me. He takes very vigorous exception to the graph in an article he wrote which he titled "Bad Astronomer Does Bad Statistics: That Wall Street Journal Editorial." I encourage you to read it, so that you can assure yourself I am not misrepresenting his arguments in any way.

I found out about this article when I saw a tweet by Dr. Briggs himself. My first thought was: Uh oh. I sure hope I didn’t make a math mistake somewhere in my WSJ post! I better read Briggs’ article and see… So I read it.

My next thought after reading his arguments was then: Ho-hum. So?

The mismeasure of an argument

Basically, Briggs accuses me of not understanding statistics, of not including error bars, of misrepresenting that points in that plot, of not displaying the plot correctly, and so on ad nauseum. His biggest claim: that those points aren’t measurements at all, but estimates.

Here’s the thing: he’s wrong. Those point are in fact measurements, though they are not raw measurements right off the thermometers. They have been processed, averaged, in a scientifically rigorous way to make sure that the statistics derived from them are in fact solid. The Berkeley team describes in detail how that was done (PDF), and does actually call them estimates, but not because they are just guessing, or using some arcane computer model. They are technically estimates, in the sense that any measurement is an estimate, but they are really, really good ones. Greg Laden tears this use of words apart, as well as pretty much everything else Briggs wrote.

Oddly, Briggs then goes on to call them "predictions" for some reason, and that they came from "models", which is just weird. It’s as if he’s trying to use a word choice that raises doubt about the measurements. But again he’s wrong. They really are measurements, not model predictions. At Open Mind, Brigg’s word choice once again is ripped apart. [Note: Briggs has left a comment there, further verifying the fact that his use of words is incorrect.]

This reminds me of one of my favorite skeptic jokes. Question: How many legs does a dog have if you call its tail a leg?

Answer: Four. It doesn’t matter what you call a tail, it’s not a leg.

There are many other places where Briggs makes mistakes that render his arguments null; for example, the error bars (what statisticians usually call "uncertainty") are in fact made available by the Berkeley team, and are small compared to the long-term rise in temperature. For another, Briggs says I should’ve shown the plot going farther into the past, because 1973 was actually a low point. However, that’s completely wrong: it’s actually a high point! As Deep Climate points out here, this actually makes the warming trend lower. So in true contrarian fashion, Briggs is contrary even to himself. It’s bizarre.

So really, there goes Briggs’ argument. His main point is wrong, so we’re done, right?

Well, no. There’s more fun to be had here.

Beside the point

If you read Briggs’ article, you certainly get the impression that because the graph I use is statistically meaningless (so he incorrectly claims), then my whole argument about global warming is wrong.

And this is where I found myself greatly amused, though in a schadenfreude sort of way.

Think of it this way: if my argument hinged on that graph, and I removed it, my argument would have no foundation, correct? It would change the tenor of the entire blog post.

Go look at my article. If you remove that graph from it, what changes? Nothing. My main point — that the WSJ and DM articles are wrong, that we have lots of evidence the Earth is warming up, that 9 of the 10 hottest years on record occurred since the year 2000, that the DM article specifically uses scientific studies and presents them as if they say the exact opposite of what they actually say — still stands.

So even if that graph is wrong and misrepresents what I’m saying — which it does not — it doesn’t matter. In fact, I used that graph as an illustration, to show how we’re warming up. I never intended it to be the basis for the argument I was making, just a way of further showing it. If you read the actual words I wrote, including the links to many, many articles backing up my position, you’ll see that Briggs has not refuted a single actual point I made.

So even if he’s right about that graph, it doesn’t matter. And he’s not right.

But notice what he’s done. He’s taken what is clearly a minor point and blown it up as if it’s my main point. He’s used shady words (predictions, models) to cast aspersions, and to make someone (me!) look bad. Then, by "refuting" this minor issue he can then poison the well, strongly implying that all my arguments are wrong. That’s kind of a big no-no when trying to argue a point.

But it packages well. Watts Up With That, another denialist blog, has run with Briggs’ claims about me as well. He also makes the false claim that warming has stalled, and so on. Note WUWT also says the signers of the WSJ OpEd are "16 scientists", which isn’t true: not all are scientists, and only four have actually published climate science research. And don’t forget about the article the WSJ refused to print talking about the reality of global warming, signed by 255 actual scientists.

Oops.

Denialism’s dark mirror

I will admit the irony of this attack amuses me greatly; Briggs accuses me of many things he himself is doing. That is standard fare from antiscience group: creationists, global warming deniers, and alt-medders, for example, all seem to project their own tactics on the scientists with whom they disagree. Don’t like real medicine? Accuse scientists of being in the pocket of Big Pharma (and forget about the millions being made by quacks on useless "remedies"). Don’t believe in evolution? Accuse scientists of being too dogmatic. Don’t think global warming is real? Accuse scientists of misrepresenting the data.

My favorite irony is that a lot of these global warming denialists take money from fossil fuel interests, but then routinely say to "follow the money", as if it’s the climatologists who are raking in the big bucks from shady think tanks with undisclosed bankrollers. While Briggs points out he gets no money from them, he asks where my money comes from. Think on this, Dr. Briggs; how much money would I make if I suddenly turned coat and said global warming wasn’t real? I’ll guarantee you it would be a lot more than I make now, probably with a couple of zeroes added to the end. So that argument falls a wee bit flat here.

Like all the others.

Of course, given the comments I’ve seen on my blog, on Briggs’ blog, on Watts Up With That, or in any other blog discussing global warming, I know how this will go. You can bring up the major pieces of evidence supporting reality again and again, but the denialists will ignore them and go after phantoms instead. Because if they do acknowledge the actual evidence, they lose.

Over the course of several hundred years – most notably in the 17th and 18th centuries — winter temperatures in western Europe were much lower than normal. Glaciers came much farther south than they had before, and a famous painting shows people ice skating on the Thames river — which hasn’t been frozen since. The period is known as the Little Ice Age, and its cause has always been something of a mystery.

However, new research by scientists at the University of Colorado-Boulder (yay team!) may have pegged it: the LIA appears to have started abruptly in the late 13th century, between the years 1275 and 1300. Radiocarbon dating of plants from Baffin Island (north of the Hudson Bay in Canada) and sediment samples from a lake in Iceland indicate that there was a rapid onset of severe cooling at that time. It’s been thought that the cooling started around then, but it’s been hard to pin down until now.

More importantly, this narrows down the cause of the LIA: four tropical volcanoes erupted violently in that period. The ash would have darkened the atmosphere, letting slightly less sunlight down. Some of the gases emitted by volcanoes also cool the air. It seems clear these volcanoes are what triggered the Little Ice Age. But why did it last so long?

That may be due to what happened after the volcanoes erupted. Most likely, the warmer temperatures would have melted the north polar sea ice. This fresh water is less dense than salty water, so it would flow on top of the oceans, and wouldn’t have mixed well with the deeper water. This would have slowed the transport of heat from the equatorial waters back up north, cooling them further. That system is what maintained colder temperatures for so long. There were variations — the Ice Age was more of as series of pulses of temperature drops than one long period — but for centuries the heating of the Earth was disrupted in that region.

For a long time it’s been suspected that the Sun played a role here, too. During the period of 1645 to 1715 there were few or no sunspots, a time called the Maunder Minimum. Sunspots are dark, but they’re surrounded by a region, a rim, that emits strongly in the UV. These faculae, as they’re called, actually more than make up for the darker regions of the spots, so in reality sunspots add to the amount of light and heat the Earth receives, by a fraction of a percent. So an active Sun, it’s thought, may warm the Earth a teeny bit more.

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