Bad Astronomy » Science

The staring eye of a crescent moon

Phil Plait — Fri, 10 Feb 2012 17:39:56 +0000

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 ...

A hoopy frood

Phil Plait — Fri, 10 Feb 2012 14:00:58 +0000

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 ...

Science Getaways: Update

Phil Plait — Tue, 07 Feb 2012 16:36:40 +0000

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" ...

Superbowl science 2012

Phil Plait — Sun, 05 Feb 2012 23:14:17 +0000

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 ...

Q&BA: Pound for pound, are humans hotter than the Sun?

Phil Plait — Thu, 02 Feb 2012 18:19:08 +0000

[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 ...

A case study of the tactics of climate change denial, in which I am the target

Phil Plait — Thu, 02 Feb 2012 14:00:35 +0000

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 ...

What caused the Little Ice Age?

Phil Plait — Wed, 01 Feb 2012 14:00:31 +0000

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 ...

Q&BA: What happens if you are exposed to the vacuum of space?

Phil Plait — Tue, 31 Jan 2012 19:21:08 +0000

[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. ]

A lot of people, it seems, have morbid thoughts about space. Why else would I get asked this so much: "What would happen to the human body exposed to the vacuum and cold of space?"

Of course, this sort of thing is depicted in scifi movies a lot, and people are curious about it. And even though the movies always get it wrong — you don’t explode, or freeze instantly — it does make folks wonder about it. And while the reality isn’t maybe as gooey as in the movies, it’s still pretty nasty.

I wrote about this in my review of the movie "Mission to Mars", as well as answering a question many years ago from a reader. And even though it’s an icky thing to think about, it does give me a chance to talk about heat transfer, which is pretty, um, cool.

Does the planet Fomalhaut b exist?

Phil Plait — Tue, 31 Jan 2012 14:00:34 +0000

Well, this is depressing: Fomalhaut b may not exist.

Fomalhaut is one of the brightest stars in the sky, and is only about 25 light years away — that’s close, on a cosmic scale. It’s young, not more than a few hundred million years old, and surrounded by a vast ring of dust, leftover from the formation of the star itself. The ring is about 20 billion km (12 billion miles) in radius, and has a sharp inner edge.

That last bit is important: the easiest way we know to make the inside edge that well-defined is if a planet is orbiting the star just inside the ring. Its gravity would draw in particles, sculpting what would otherwise be a fuzzy boundary into a clean-cut ring. Not only that, but the ring is off-center; again, that’s likely due to the gravitational influence of a planet.

In 2008, astronomers announced they had found that planet: it appeared in two different Hubble Space Telescope images (shown above; click to embiggen) separated by two years. During that time, it had moved a little bit, by just what you’d expect for a planet ...

Q&BA: Getting kids into science

Phil Plait — Mon, 30 Jan 2012 21:24:55 +0000

A few years ago, I started doing a weekly video question-and-answer session I called "Q & BA". It was a series of short videos that were a lot of fun to make. Unfortunately, the overhead got to be too high — it took all day to edit them! — and I had to stop.

But now, Google+ has changed that: Hangouts On Air is a feature that allows me to go on camera and broadcast a live video chat session to an unlimited audience. I take questions via Twitter and G+, and it’s a lot of fun. It lasts about an hour, and I put the whole session on YouTube. But some of the answers stand alone, and it’s easy to extract them out, package ‘em up, and post ‘em by themselves.

So I’m very pleased to announce I’m starting the series again! The first Q&BA is a great question: "What’s the best way to get kids into science and skepticism?" — what better way to get the series going again? Enjoy.

I’ll be posting more of these, maybe even one per day as time allows. If ...

Real time footage of aurora shows them dancing and shimmering

Phil Plait — Sun, 29 Jan 2012 05:56:25 +0000

Photographer Alistair Chapman traveled to Tromso, Norway — 300 km north of the Arctic Circle — to capture video of the aurorae from the recent spate of solar storms. What he caught on camera is remarkable: shimmering, waving, dancing lights moving in real time!

[Make sure you set it to 720p; Chapman says higher-def footage is coming soon.]

That’s amazing. Aurorae video is generally done with time lapse to show the movement, which is usually slow. I’ve often wondered just how fast the movement really is; I always figured fluctuations in the solar particle density, speed, and magnetic fields would produce real-time changes in the lights, but I’d never seen anything like this! After a search of YouTube I actually found several more.

I know some people will think this is fake, and I had my skeptic hat on while watching it. Note that in most time lapse you can see the stars move; in this they don’t, indicating (unless it’s a complete fake) short periods of time during the filming. Given that, plus the existence of other video like it, I’m thinking this is real.

Mind you, the movement you’re seeing isn’t a physical motion. It’s ...

This is a galaxy

Phil Plait — Thu, 26 Jan 2012 19:23:16 +0000

I have nothing to add to this, except to say it’s great, and I saw it because Brian Cox mentioned it on Twitter.

Oh yeah: one more thing; watch it in HD and full screen. Coooool.

Independent researchers find no evidence for arsenic life in Mono Lake

Phil Plait — Mon, 23 Jan 2012 21:04:32 +0000

Late in 2010, scientists participating in a NASA news conference dropped a bombshell: they had found evidence that bacteria in California’s Mono Lake were metabolizing arsenic and using it in their life processes.

This was huge news, since arsenic is toxic for carbon based life. If some forms of life evolved a way to process it, this would open up a whole new field of biochemistry!

However, almost immediately, the work came under attack. Biochemists accused the original team of not performing the research carefully (to put it delicately). Rosie Redfield, a microbiologist at the University of British Columbia in Vancouver, was particularly critical. She decided, in fact, to try to verify the original work, and set out to do so openly, writing up her progress on her blog.

And now, according to an article on Scientific American, she can confidently provide a "clear refutation" of the arsenic uptake in the organisms:

Their most striking claim was that arsenic had been incorporated into the backbone of DNA, and what we can say is that there is no arsenic in the DNA at all.

That’s a pretty clear statement! The ...

Wait just a (leap) second

Phil Plait — Mon, 23 Jan 2012 14:00:43 +0000

This summer will be a little bit longer than usual. A tiny little bit: one second, to be precise. The world’s official time keepers are adding a single second to the clocks at the end of June. This "leap second" is needed to keep various time scales in synch. It’s a bit of a pain and won’t really affect people much, but if it weren’t done things would get messy eventually.

This gets a bit detailed — which is where the fun is! — but in short it goes like this. We have two systems to measure time: our everyday one which is based on the rotation of the Earth, and a fancy-schmancy scientific and precise one based on vibrations of atoms. The two systems aren’t quite in synch, though, since the Earth counts a day as a tiny bit longer than the atomic clocks say it is. So every now and again, to get them back together, we add a leap second on to the atomic clocks. That holds them back for one second, and then things are lined up once again.

There. Nice and simple. But that’s spackling over all ...

For moons, size does matter

Phil Plait — Fri, 20 Jan 2012 14:00:40 +0000

One of these things is not like the others:

The Cassini spacecraft took this lovely image in December 2011, during a close pass of Saturn’s moon Dione. Ignoring Saturn’s rings slashing through the picture, we see, from left to right, the moons Dione, Prometheus, and Epimetheus. Which is the odd moon out?

Here’s a hint: Dione is 1100 km (700 miles) across, Prometheus 86 km (53 miles) along its longest axis, and Epimetheus 113 km (70 miles). Got it now?

Yeah, sure, Dione is far larger than the other two! But that’s not my point: Dione is round, while the other, smaller moons are lumpy and rather potato-shaped. Why?

Size matters. In this case, a bigger moon means more mass, and that means more gravity. In general, the force of gravity points toward the center of an object. As you add more mass to an object, gravity gets stronger. On a small moon, a big lump of rock like a mountain feels very little force downward, while on a more massive moon the force would be larger. If the moon has enough mass, and enough gravity, the force will be ...

The Sun fries a comet and we got to watch

Phil Plait — Thu, 19 Jan 2012 23:11:30 +0000

In July of last year, I wrote about a comet that passed extremely close to the Sun. Astronomers have now had a chance to pore over that data, and were able to determine some very cool stuff.

First, here’s the video of the comet’s fiery demise (watch it in HD to make it easier to spot the comet):

See it? It’s faint, but there. Actually, there are a lot of observations from multiple observatories and detectors, which allowed astronomers to find out quite a bit about this doomed chunk of ice and rock.

For one thing, it was screaming along at about 650 kilometers per second (400 miles/second) as it flamed out. To give you an idea of how flippin’ fast that is, it would’ve crossed the entire United States in about eight seconds.

Yeah, I know.

It also passed an incredible 100,000 km (62,000 miles) above the Sun’s surface. Have you ever stood outside on a hot day, and thought the Sun would cook you? Now imagine the Sun filling half the sky. That’s what that comet saw. No wonder it disintegrated.

As ...

Brian Brushwood is super cool

Phil Plait — Wed, 11 Jan 2012 17:55:20 +0000

… and I mean that literally. Here he is, supercooling a beer.

Supercooling is when a liquid is chilled to a temperature below its freezing point, but it remains a liquid. Water, for example, will crystallize when it freezes, but it needs a starting point for that to happen, like a particle of some impurity (a mineral, for example), or the rough wall of its container. If you freeze a container of (distilled) water without jostling it, it’s possible to supercool it. If you then carefully remove it from the freezer and shake it or pour it over ice, it’ll freeze instantly*.

This is similar to superheating, where a liquid can be heated beyond its boiling point but remain a liquid. This happens all the time for me when I boil water in my microwave using one particular Pyrex measuring cup. I have to be careful — I might say super careful — when removing it, because if jostled the water will erupt with steam and explode outwards. To call that dangerous is a massive understatement; water can carry a lot of heat and the resulting burns are no fun at all.

… which is how I discovered that ...

Google+ astronomy weekly roundup video now online

Phil Plait — Fri, 06 Jan 2012 16:00:24 +0000

Yesterday, I was in a live video chat session with several other scientists and science journalists. I wrote up the details of it yesterday, and it went pretty well! We had a lot of fun talking about the new GRAIL Moon mission, the fiery future return of Phobos-Grunt, 2012, and of course President Obama’s purported teleportation trip to Mars many years ago.

Wait, what?

Well, if you wanna know more, now you can: the video’s online.

The plan is to do these every week on Thursdays, and have a rotating cast of characters over time. I hope you like it. And I strongly suggest people join up over at Google+. I really like it there, and post quite a few things you won’t see here or on Twitter.

Live weekly astronomy roundup on Google+!

Phil Plait — Thu, 05 Jan 2012 17:10:55 +0000

Fraser Cain (from Universe Today) and I are trying something new… and by new, I mean new. We’re going to be holding a live video weekly astronomy and space roundup on Google+! We’ll have a roundtable group of scientists and science journalists discussing the latest cosmic news, explaining it, and letting you know what it all means. We have a pretty good group of folks lined up for this, and the first one will be held today, Thursday, January 5 at 18:00 UTC (1:00 p.m. Eastern US time).

[UPDATE: We're live now!]

These will be held on Google+ using Hangouts on Air – a live video stream that can be watched by an unlimited number of people. You have to be on Google+, and then circle Fraser Cain — that’s G+’s version of adding friends. He’ll have the link to the video feed in his stream once it’s set up (and I’ll update this very blog post as well). And once you’re in, you can ask questions for us in the comments section on the post! You can read more about this on Universe Today.

I’m very excited about these live video news session. For one thing, ...

NASA sends GRAIL shaped beacon to the Moon

Phil Plait — Sun, 01 Jan 2012 22:14:42 +0000

Mynd you, Møøn bites Kan be pretti nasti…

Today, NASA successfully put a new mission into lunar orbit: GRAIL, for Gravity Recovery and Interior Laboratory. Great acronym, weird name, right? What this mission will do is map the gravity field of the Moon, and use that to probe the interior composition. The basic idea isn’t all that complicated: fly a probe around the Moon. If it goes above a region where the density is higher, there will be a slightly stronger gravitational pull, and the spacecraft will accelerate a bit. By carefully measuring the spacecraft position and velocity, you can make the lunar gravity map.

In detail, that’s a bit tougher! What NASA has done is launch two probes, GRAIL-A and GRAIL-B, that will fly in the same orbit, one behind the other*. They’ll stay in constant communication, sending radio pulses to each other. The timing of these pulses allows an extremely accurate determination of their separation: their distance will be known to an accuracy of about a micron: that’s a hundredth the width of a human hair, or the size of a red blood cell!

So how does ...

Why are atoms mostly empty space?

Phil Plait — Wed, 28 Dec 2011 14:00:18 +0000

Professor Brian Cox is a physicist in England, very well-known there as a popularizer of science. The reasons for this are many-fold, including his ubiquity across media (including podcasts, Twitter, and of course TV)… but also because he has an infectious enthusiasm for science coupled with a boyish charm.

This was all on display recently when he hosted a great segment on the BBC’s show A Night With The Stars, where he simply and effectively demonstrates why atoms are mostly empty space:

Pretty cool, isn’t it? It helps if you can enlist Simon Pegg to help, too!

I like this demo a lot. On a very tiny scale, objects act like both particles and waves. On a big scale, like our solar system, we can think of planets as discrete particles, interacting through gravity only, and it works pretty well. Our semi-evolved brains want to think of electrons that way as well: little spheres whizzing around atomic nuclei. But that’s not the way the Universe works on the quantum scale; electrons act like waves, and that means they can interfere with each other. When a crest meets a trough they cancel, ...

Mass effect: Maybe Higgs, maybe not

Phil Plait — Tue, 13 Dec 2011 16:29:43 +0000

Today, scientists at CERN in Geneva announced their results for their search for the Higgs boson, a subatomic particle that, if it exists, is thought to be responsible for giving other particles mass. It’s no exaggeration to call it a keystone in quantum mechanics, and finding it for sure will be a huge accomplishment for particle physicists.

So, did they find it?

Maybe. Then again, maybe not.

Um, what? OK, this’ll take a wee bit of explaining.

Last things first

I said Higgs, Magnum. HIGGS.

First, the conclusion, so at least you have that in mind as you read the rest. There are two experiments running at CERN looking for the Higgs particle. They don’t smash particles together, look around with magnifying glasses and tweezers, and then yell “AHA!” when they find one. Instead, they build up a picture of it after doing gazillions of particle collisions. After a year of runs, both experiments see something that might be Higgs, but they’re not 100% sure. One sees something at about the 94% confidence level, the other at 98%. That’s pretty good, but it’s not enough to be completely sure. It seems likely they’ve found ...

Mesmerizing visualization of a geomagnetic storm

Phil Plait — Wed, 07 Dec 2011 19:00:45 +0000

When the Sun belches out an eructation of subatomic particles, they can travel across the solar system and interact with the Earth’s magnetic field. This can make our field ring like a bell, shaking the particles trapped within, and generating electromagnetic noise and signals across the radio spectrum. The CARISMA radio array can detect these emissions and learn about how the Sun’s and Earth’s fields interact.

That’s the science. But there’s art here, too: the Lighthouse agency commissioned artists to create digital artwork based on science, and one group, Semiconductor, used the CARISMA data to do so. Based on the data, they translated the radio waves (which are like the light we see, but less energetic) and converted them to sound. This has been done many times before, but what’s cool is that they then created an animation based on the converted sounds, an astonishing and odd and mesmerizing animation. Watch:

How wild is that? It reminds me of the movie "Forbidden Planet". The vibrating patterns are wonderful, and while I’m not sure how much scientific insight can be gained from them, the aesthetics are riveting. And I can hope ...

Science Getaways

Phil Plait — Wed, 07 Dec 2011 14:00:53 +0000

I am very pleased to announce the grand opening of Science Getaways, where you can take a vacation with your brain!

Science Getaways is a new travel company, started by my wife Marcella and me, for science enthusiasts who want to do more than just take a vacation: they want to feed their brain, too. Over the years I’ve been to a lot of cool places, but I’ve always found my experience is enhanced a lot by learning about the science of the region: the geology, the biology, the connection to other sciences. Heck, when we visited the Galapagos Islands a few years back the whole thing was nothing but science — and it was the vacation of a lifetime (as you can read here, and here, and here). Trips like this are becoming popular enough to get written up by the New York Times.

So we decided we wanted to do this too. Voila! Science Getaways, where we do all the work for you: find cool places to take ...

A boiling superEarth joins the exoplanet roster

Phil Plait — Wed, 30 Nov 2011 19:19:13 +0000

A collaboration between space- and ground-based telescopes has added a new world to the growing list of exoplanets: Kepler-21b, a planet bigger and more massive than Earth. It’s far smaller than Jupiter, though, putting it firmly in the "small, rocky planet" category. Not that it’s Earth-like: it orbits its star in just under 3 days, making it hot enough to have pools of molten iron on its surface!

Now, I don’t generally write about every new alien planet discovered — with over a thousand of them and counting, it would be all I ever do! — but this one interested me. For one thing, it’s not all that much bigger than Earth; it’s about 1.6 times our diameter. The size was able to be found because the planet transits its star: it passes directly between the star and us, blocking the star’s light a wee bit. The amount of light blocked depends on the size of the planet itself, so by carefully measuring that dip in brightness the planet’s size can be determined.

And did I say a wee bit? I mean a really wee bit! Here ...