The entire universe in blog form

April 15 2014 1:36 PM

Blood Moon: The Lunar Eclipse of April 2014

Did you watch the total lunar eclipse last night? Judging from my Twitter feed, a lot of people did! Chatter and pictures were flying around the ‘Net as the silvery full Moon slowly drifted into the Earth’s shadow and turned a lovely shade of orange.

I took the picture above at about 07:21 UTC (01:21 Mountain time, local for me), about 15 minutes after the total phase started. You can see the bright star Spica (the brightest star in the constellation of Virgo) just to the Moon’s lower right, and the much fainter star h Virginis just above and to the left of the Moon. It was fun to see fainter and fainter stars pop up as the Moon faded away, its bright glow no longer capable of washing them away.


Over the course of an hour and a half I took some video using my camera (a Canon T41 with a 250 mm lens), so, for your eyes’ and brain’s pleasure, here it is:

I suggest making it big, if not full screen, and make sure you have the volume up for the first few seconds.

The coyotes really set the mood, didn’t they? Even though I was freezing my toes and fingers off, it was truly a wonderful and fun evening. I’ve seen a dozen or more total lunar eclipses, and I think my favorite part of this one was sharing my photos on Twitter in near real time. People all over the world were excited to see it, and that is a big part of why I do this.

A little over half an hour into the eclipse, a longer exposure reveals details on the shadowed part of the Moon.

Photo by Phil Plait

Due to the complex and subtle dance of gravity and geometry, there will be three more total lunar eclipses visible to the United States over the next year and half: in October this year, and in April and September of 2015. While there won’t be any bright stars near the Moon for the eclipse in October, the planet Uranus will be only a degree away! That’ll make for some nice family portraits. And there’s also a partial solar eclipse two weeks later, on Oct. 23, 2014, too! That’ll be a treat. And if you live in Australia there’s a nice annular solar eclipse on April 29; this is when the Moon is slightly smaller than the Sun and leaves a ring of Sun around the dark Moon. There was one of these last year and there were some fantastic pictures and video. I hope we’ll get more.

Remember: Look up! There are always amazing things to see.

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April 15 2014 7:30 AM

Cassini May Have Witnessed the Birth of a New Saturn Moon!

Discovery image of the new moon, seen as a clump of material just outside Saturn's main ring. Click to encronosenate.

Photo by NASA/JPL/Space Science Institute

Just when I think Saturn can’t surprise me any more: The Cassini spacecraft may have taken the birth pictures of a new moon! It may have also spotted its demise. Or maybe part of its demise. Also, it may be twins.

OK, let me explain.


The potential moon (nicknamed Peggy) is tiny, probably only about a kilometer (0.6 miles) across—really a moonlet—and is invisible in the Cassini pictures. However, its presence is betrayed by an odd clumping of material at the very edge of Saturn’s A ring, the outermost of Saturn’s main rings.

It was discovered by accident in an image taken on April 15, 2013—one year ago today. The picture above shows the main rings, the thin F ring outside them, and the irregularly shaped moon Prometheus (the actual target of the shot) in the center just inside the F ring. If you look carefully you can see a blob on the edge of the A ring. Here’s a close-up, with the clump indicated:

That’s clearly not a discrete object; it’s about 10 kilometers (6 miles) wide and 1,200 kilometers (740 miles) long, but this is what you would expect if a small object were located near the edge of the ring—and why astronomers think there's most likely a moonlet there. It would have feeble gravity, but enough to affect the ice particles in the ring, creating the long, trailing clump.

Saturn's new moon
Zooming in on the new moon's clump.

Photo by NASA/JPL/Space Science Institute

Once they knew it was there, the astronomers were able to calculate an orbit for it, and then go back and look for it in older Cassini images. They found the clump in more than 100 such pictures! But in most cases it’s so faint and difficult to see that it was completely overlooked before. It appears brighter at certain viewing angles, which is why it was so obvious in the discovery image. The earliest it was seen was in May 2012, but before then Cassini was not in a good orbit to detect the clump, so there’s no way to really know how old it is.

But then things get weirder. In images taken before January 2013 there’s only a single object, but in later images, just around the time the object was discovered, a second one appeared! They’re obviously related, but it’s not clear whether the main object broke up due to a collision with something else, or whether Saturn’s tides (the change in the force of gravity over distance) pulled it apart. It may also be due to some other mechanism entirely.

I dug up another of the images showing the clumps, taken on June 22, 2013:

The two elongated clumps are indicated; they are just outside the main ring. Click to embiggen.

Photo by NASA/JPL/Space Science Institute

I’ve indicated their locations; you can just see a gap between them and the main A ring. Once I knew what to look for they were obvious, but I can see why they could’ve been missed before. They’re hard to spot. I’ll note that in other images they found what may be a third object as well, but it’s difficult to know what its relationship is to the other two (if any).

And we’re still not done. Not long after the discovery image, Object 2 disappeared! Due to complex interactions with the ring particles, an object the size of the small moon can migrate outward, away from Saturn, over time. Once it leaves the rings it would become essentially invisible. An alternate explanation is that it disintegrated; if its orbit was a bit eccentric, a bit stretched, compared to the particles in the rings it would have been continually bombarded by them, and could have been obliterated.

Still, it was there, at least for a while. And the other object may have survived as well.

So I suppose congratulations are in order for Saturn on its possible new moon … but it’s funny. Saturn is the Roman name for the Greek god Cronus (or Cronos), who was known for eating all his children to prevent them from overthrowing him (when you get down to it, a lot of the ancient myths are really, really horrid). But now we find out the opposite is true! The smaller moons may have been birthed by Saturn (or at least, its rings) and moved out before they could get eaten.

Science! I’ll take it over myth any day.

April 14 2014 2:28 PM

Science Ranch 2014: A Few Spots Left

There are only a few spaces left at Science Ranch 2014, a weeklong science-based vacation with me, June 22-28, at the Waunita Hot Springs Ranch in the Rocky Mountains near Gunnison, Colo. In addition to your humble host, we’ll have a geologist and an ecologist with us all week as well. There’ll be science talks, stargazing, nature hikes, horseback riding, rafting, great food, and special programs just for kids. We’ll also be taking a day to visit the staggeringly dramatic Black Canyon, which seriously has to be seen to be believed (check out this photo, for example).

My wife and I both love science, and when we go on vacation we always want to learn more about the natural history of where we travel … that’s why we started Science Getaways. We bring along professional scientists to tell us about what we’re seeing and to answer your questions, and I bring my 8” Celestron telescope so we can view the heavens. The dark skies at Wuanita should provide fantastic views (weather permitting, but summers in Colorado are almost always quite lovely and clear). You’ll have a great time, and you’ll learn something, too.


It’s a vacation with your brain.

April 14 2014 11:09 AM

No, Scientists Have NOT Found Life in a Meteorite. Again.

Hey, look! This again. An article claiming scientists have found microscopic life in a meteorite. I’ve been getting emails from folks (mostly via Facebook) asking whether this is real.

OK, let’s put this in context: For as long as humans have looked at the stars, we’ve wondered if there is life in space. Once science and technology caught up with our imagination we started using radio telescopes to listen for alien signals, we built giant telescopes on space and on the ground to search for other planets, and spent billions of dollars sending missions to Mars to looks for signs that there was once water flowing there, and even just the potential for life.


So if scientists found actual microbes—living bacteria, as claimed in this case—inside a meteorite that fell from space, I think it might make somewhat bigger news than being reported on some random news-like website you saw linked from Facebook.

And I say "news-like" website because the site in question, World News Daily, is satirical. It has articles with headlines like, “Former Pope Warns of Vatican Alien Agenda” and “Arctic Penguins Now Extinct” (think about it…).

And if the site is being serious, then its scholarly levels make the Daily Mail look like the New York Times.

The article itself is a clever mix of reality and outright crackpottery. It mentions real scientists, like Peter Brown, who is in fact a meteoriticist. The meteorite discussed in the article is claimed to come from a fireball that occurred on March 18, 2014 over southern Ontario; a real event (though, to my knowledge, no meteorites from it have yet been found).

The article also mentions Charles Bolden, the NASA administrator. The quote has a, um, key tell in it:

The general director of NASA, Charles F. Bolden, saluted the discovery and praised the canadian university for it’s exceptional contribution to the world’s astrological knowledge.

Emphasis mine. But I hope you see the point (not to mention the two grammatical errors).

Separated at Earth? The claimed Ontarian rock (left), and one found a few years ago in Antarctica (right). Hmmm.

Photo from World News Daily and the University of Toronto/Ray Jayawardhana

Also, on a hunch, I did a reverse image search on Google using the picture of the meteorite shown in the article. It turns out to be one found in Antarctica a few years back. That’s a bit of a walk from Ontario.

So yeah, to be clear: This article is 100 percent bovine excrement, fertilizer, baloney, nonsense, hokum, and fish-wrappery.

Got it?

I can understand it spreading, though, especially on social media. It only takes one person to post about it (either missing the signs it was satire and taking it seriously, or sharing it as a joke) to get things started. People tend not to read past headlines—did you see the NPR April Fools’ Day joke that proved this?—or in general they just skim an article like this. And even if they do a quick check of the facts by, say, looking up the Ontario fireball event or the names of the scientists, they’ll find they’re real (though I suspect the number of people who would go that far is negligible).

Making it worse is that actual scientists have been making similar claims about life in meteorites lately, all of which have been utterly wrong (see Related Posts below for more about them). Those claims were just plain old bad science, but people half-remember them, and so it's no surprise to me that a joke article can wind up getting taken seriously.

Remember folks, put stuff in context! If the news is this big, you would’ve heard about it sooner and in a more reliable venue. And even that doesn’t make it true; you have to do a little work, dig a little deeper, to get to the truth.

Before hitting that button to send something to all your friends, remember: If you care enough to share, you should care enough to beware.

OK, wow, that was an awful aphorism. How about this: Before you share, use a skeptical glare.

Yeah, that’s worse. Whatever. All I ask is that you hesitate a moment before sharing a story like this one so you can think it over. Does it make sense? Is there another place I can look for more info (cough cough)? Is there a chance this is a joke/hoax/fake/wrong?

If you do that, then you’re well on your way to making the world a more real place. And I thank you for it.

Related Posts

April 14 2014 7:30 AM

Watch the SpaceX Launch Live Today at 20:58 UTC

Today (Monday, April 14, 2014), SpaceX is scheduled to launch a modified Falcon 9 rocket on a resupply mission to the International Space Station. The launch is scheduled for 20:58 UTC (4:58 p.m. EDT), and you can watch it live on NASA TV or Ustream (I prefer the latter; there’s less lag in the video stream).

This third mission for SpaceX to the ISS has some interesting stuff going on. I think the most exciting is the Optical Payload for Lasercomm Science, or OPALS. Spacecraft currently communicate with the ground via radio transmissions, the signal encoded with information much the way as how a radio in your car works. OPALS will use an optical light laser for this instead, which is a big leap forward if it works. Lasers take very little power, and the shorter wavelength of optical light means a lot more info can be encoded into the beam. This test will beam a video taken on ISS along with other information down to the ground.


When I was a kid, I read all of science-fiction author Larry Niven's stuff, and his ships communicated using lasers (they played key roles in several stories, too). When I got older I realized how many advantages there were to using lasers instead of radio, and now it's becoming a reality. Score another one for sci-fi.

Two other payloads include a suite of hi-def cameras that will take video of Earth (to test which designs work best in space) and a nifty package (called Veggie) that will allow the astronauts to grow vegetable plants in space using LED lights.

But there’s still another cool thing: SpaceX will be testing the hardware needed to have the first stage of the Falcon 9 rocket land itself for reuse. This is an idea they’ve been testing with their Grasshopper series of test flights, using landing legs stowed on the side of the booster. After the stage separation (and the second stage lofts the Dragon capsule up into space), the booster will execute a burn to slow down, and the legs will deploy during the burn. This will all happen over the Atlantic Ocean, so it’s not an actual full-up landing burn; it’ll be a splashdown! But it’ll test many of the needed systems for an eventual and literal landing. SpaceX says the odds of this being a completely successful test are low, but it’s worth giving it a shot.

Once the Dragon capsule is in orbit it’ll rendezvous with ISS and berth on April 16. If there is a delay in launch, the next possible launch date is April 18. Various hardware issues on the Dragon and ISS have delayed the original scheduled launch, but engineers have decided it’s a go for today.

SpaceFlightNow will have fairly up-to-date messages loading on its site for more information. I’ll be watching and live-tweeting as well, of course. Watching a rocket launch is always fun, so I hope you’ll join in.

April 13 2014 7:30 AM

Jenny McCarthy: “I’m Not ‘Anti-Vaccine’”

Jenny McCarthy
Which Jenny McCarthy should we believe?

Photo by DFree / Shutterstock

Jenny McCarthy is claiming she is not anti-vaccine.

Here’s the problem with that claim: Yes, she is. That’s patently obvious due to essentially everything she’s been saying about vaccines for years. Yet in an op-ed in the Chicago Sun-Times on April 12, 2014, she tries to ignore all that, and wipe the record clean.


In case you think I may be misquoting her, here is the first line of that op-ed: “I am not ‘anti-vaccine.’”

So, there you go.

She says she’s never told anyone not to get vaccinated. Assuming that's true, great! But that’s hardly the entry-level position for being anti-vax. For example, you can say things that are grossly incorrect about them that would scare parents into not vaccinating their children. That would fit the moniker “anti-vax,” I’d think.

So, for example, saying vaccines have toxins in them—as she has said for years, and as she reiterates in her op-ed—is a clear sign of being anti-vax. After all, if someone tells you you’re putting toxins in your body, that sounds awful, doesn’t it? Doesn’t that make you want to stop doing whatever it is that’s putting them inside you?

Yet as doctors say, dosage makes the poison. The amount of, say, formaldehyde in a typical vaccination is much less than you’d get eating an apple. The same can be shown for the other ingredients claimed to be toxins in vaccines as well. The truth is vaccines contain far too small a dose of any of these things to cause any of the problems McCarthy and other anti-vaxxers claim exist.

Also, botulinum is the single most lethal toxin known to humans. Yet McCarthy has enthusiastically praised injecting this toxin into her face. How can anyone possibly say that and also say vaccines have dangerous levels of toxins in them with a straight face?

Which brings us to autism. McCarthy is still claiming that there is a link between vaccines and autism. However that is simply not true. Again and again and again and again this has been shown. McCarthy asks us to talk to families of people who have children with autism. That's certainly a good place to start, but it's the first step to an answer, not the last. Anecdotes are not data. We know people are subject to dozens of different biases that lead them down the wrong path when trying to determine cause and effect. That’s why medical studies are done so carefully, to make sure we aren’t fooling ourselves. And the studies clearly show no connection between vaccines and autism.

And finally, let’s take a step back and look at the claim that she’s not anti-vax itself. Jeffrey Kluger is a science writer for Time magazine. He interviewed McCarthy in 2009 about this issue, and she mentions that interview in her op-ed piece. Kluger disagrees vehemently with what she wrote in the op-ed, to say the very least.

I can see why. Here is what she writes in the op-ed:

“People have the misconception that we want to eliminate vaccines,” I told Time magazine science editor Jeffrey Kluger in 2009. “Please understand that we are not an anti-vaccine group. We are demanding safe vaccines. We want to reduce the schedule and reduce the toxins.”

But Kluger points out that she left the last line out of that quotation. Here’s the whole thing:

People have the misconception that we want to eliminate vaccines. Please understand that we are not an antivaccine group. We are demanding safe vaccines. We want to reduce the schedule and reduce the toxins. If you ask a parent of an autistic child if they want the measles or the autism, we will stand in line for the f--king measles.

Huh. That last line rather changes the tone of her position considerably, wouldn’t you agree? That’s a difficult stance to square with someone who is not anti-vaccine. As Kluger points out, her entire premise is false; since vaccines don’t cause autism, no one has to make the choice between measles (and other preventable, dangerous diseases) and autism.

Kluger finishes with this:

Jenny, as outbreaks of measles, mumps and whooping cough continue to appear in the U.S.—most the result of parents refusing to vaccinate their children because of the scare stories passed around by anti-vaxxers like you—it’s just too late to play cute with the things you’ve said. You are either floridly, loudly, uninformedly antivaccine or you are the most grievously misunderstood celebrity of the modern era. Science almost always prefers the simple answer, because that’s the one that’s usually correct. Your quote trail is far too long—and you have been far too wrong—for the truth not to be obvious.

He’s right. She has gone on and on and on and on and on and on about it. She can claim all she wants that she’s not anti-vax, but her own words show her to be wrong.

Anti-vax is as anti-vax does. And she does.

April 12 2014 7:30 AM

Don’t Miss the Lunar Eclipse on April 14–15!

Do you live in North America, South America, Australia, or eastern Asia? Then you get to see a lunar eclipse on the night of April 14–15! And while North America is the best place to watch—we’ll get to see the whole event—the real action doesn’t begin until 05:58 UTC on the April 15, which is just before 02:00 EDT, so it’s a bit late. You might just want to stay up for it, though.

A lunar eclipse is when the Moon slips into the shadow of the Earth and gets dark. Unlike a solar eclipse (where the Moon blocks the Sun) a lunar eclipse lasts for hours and is perfectly safe to observe without protection. In fact, I find using binoculars is best!


How does this work? The Sun lights up the Earth (big duh there), and anything that’s illuminated casts a shadow. Normally the Earth’s shadow just goes off into space, but sometimes the geometry works out that the Moon passes into it. The Moon has to be opposite the Sun in the sky for that to happen, so lunar eclipses only happen when the Moon is full.  

geometry of an eclipse
Schematic showing the geometry of a lunar eclipse. not to scale (duh).

Drawing by Shutterstock/fluidworkshop

The Earth actually casts two shadows; a wide, fuzzy one called the penumbra and a narrower, darker one called the umbra nested inside the penumbra. If the Sun were a point source in the sky (a little dot) there would only be one dark shadow, but because the Sun has a finite extent (that is, we see it as a disk) the geometry is a little more complicated. If you could see the shadows in the sky, the penumbra would be a big circle about five times wider than the Moon, and the umbra would be a circle inside it about half that size.

By taking several exposures during a partial lunar eclipse in 2008, Anthony Ayiomamitis was able to create a mosiac showing the Earth's umbra cast into the sky.

Photo by Anthony Ayiomamitis, used by permission

It helps to think of it from the Moon’s viewpoint. If you were standing there, looking back at the Earth and Sun, you’d see the Earth (barely; you’re seeing it’s night side) sliding slowly over the face of the Sun. At the moment the edge of the dark Earth starts to block the sun, you’re entering the penumbra. It’s getting darker, but most of the Sun is still unblocked, so it’s not getting very much darker. About an hour later the Earth completely blocks the Sun, and you’ve entered the umbra. The Earth is much bigger than the Sun from your point of view (about four times larger) so the Sun stays blocked for a while. Finally, the Sun peeks out the other side of the Earth; you’ve left the umbra and are in the penumbra again, and things start getting brighter.

lunar eclipse seen from the moon
A lunar eclipse ... seen from the Moon! This was taken by the Japanese Moon probe Kayuga in 2009 and shows the Earth eclipsing the Sun.

Photo by JAXA/NHK

What does this mean for us here on Earth? We’ll see the Moon enter the penumbra at 04:53 UTC April 15, or 00:53 EDT (53 minutes after midnight). Again, it’s no big deal, and you’d hardly notice. But the Moon’s edge enters the darker umbra at 05:58 UTC (01:58 EDT) and over the course of a few minutes you’ll see that part of the Moon get dark. Over the next hour or so more of the Moon will fall into the Earth’s darker shadow, and at 07:06 UTC (03:06 EDT) the entire Moon will be dark. It’ll stay that way for the next hour and 18 minutes, until it starts to move out of the umbra at 08:24 UTC (04:24 EDT), and will start to be illuminated by the Sun again. The umbral eclipse ends at 09:33 UTC (05:33 EDT).

Here’s a diagram that may help:

lunar eclipse timeline
How the eclipse will play out; the description is in the text below. Click to embiggen.

Diagram by Fred Espenak/NASA (modified for clarity by Phil Plait)

The Moon moves from right to left in the diagram. The positions are labeled. P1 is when it moves into the penumbra, U1 is when it moves into the umbra, U2 is when it’s fully immersed, U3 is when it starts to leave the umbra, U4 is when it’s out of the umbra, and P4 when the Moon leaves the penumbra, and the eclipse ends. The times are listed in the lower right in UTC. Subtract four hours for Eastern U.S. time, and so on.

Sometimes when the Moon is fully immersed in the Earth’s shadow it can turn an eerie blood red due to the way the Earth’s atmosphere scatters light—it’s the same reason the Sun can look redder at sunrise and sunset.

Want to hear something poetic? If you were standing on the Moon during the deepest times of the eclipse, from your view you’re seeing all the sunrises and sunsets on earth at that moment.

When someone tells you science is cold and emotionless, tell them that.

The only problem with this eclipse is the timing; it happens late Monday night/early Tuesday morning for most of the U.S. But don’t let that stop you! If you have clear skies you really should go out and look. And if you have a camera, please take some pictures! With a little planning you can get some amazing shots like the ones I’ve scattered through this post (see Related Posts below for many more). Check out this incredible time-lapse animation made by Jeffrey Sullivan of a lunar eclipse in 2011:

Observing the Moon with a telescope or binoculars during an eclipse is a wonderful thing, but if you only have your eyes, that’s fine too. It’s fun to go out every few minutes between U1 and U2 and watch the Moon get eaten by the Earth’s arcing shadow.

I hope you have clear skies and good viewing for this event! And if you don’t, never fear: There’s another one in October, then a third in April 2015, and a fourth in September 2015 too. You’ll have plenty of chances to see this lovely astronomical bit of geometrical alignment over the next year and a half.

Related Posts

April 11 2014 11:26 AM

The Perils of the Skeptic Journalist

Being a writer these days is fraught with peril. Everything you write goes out into the wild, potentially viewable by millions of people. Usually not, but it can happen. And it may not happen today, or tomorrow … but those words are out there, and someone may stumble on them a year from now, or more.

That’s an abyss that can be hard to face. As someone who’s been writing for a living for a while now, I’ve stood at that edge long enough to be familiar with it, if not actually comfortable there. I know that something I say may be overturned by time, shown wrong by updated information, or just made stale as tastes and public attention evolve.


Of course, sometimes I’m just wrong. I can deal with the others, but just being plain ol’ wrong can be a tough one.

Oh, and I’ve been wrong. The mistakes I’ve made in my articles have ranged from just simple, unimportant stumbles to some that actually cut to the heart of the point I was trying to make. Even those big ones don’t necessarily bug me too much, if the mistake is an honest one: Due diligence was done, the research was performed, but the wrong conclusion was reached.

It’s not always like that though. Sometimes the mistakes are just dumb. Self-inflicted. And this week I’ve made a few. I want to ask for your indulgence while I point them out.

Why? Well, science—meaning the seeking of reality, of truth, of objective knowledge—progresses in some ways by making mistakes, and by examining them openly. That way, we can figure out what went wrong and try to avoid doing it again. And as a skeptic, someone who tries to examine evidence honestly, airing out my errors helps keep me honest.

What follows are my mea culpae. Per errata ad astra.

The UFO and the Deer

On April 10, 2014, I posted an article deconstructing a news story about a trailcam in Mississippi that took pictures of some deer at night. It also caught a strange glow, and several weird shapes. I’ve seen that sort of thing before—internal reflections of light in the camera—and immediately figured that’s what these were. The source of light occurred to me immediately; I checked some software, and sure enough the full Moon rose within minutes of the pictures being taken. Done and done, I figured.

Except I wasn’t quite right. It turns out the reflections were not due to the moon, but instead were from bright infrared LEDs on the camera. The folks at Parastupid have a pretty good breakdown of this. It’s funny; the heart of what I was saying was actually right; it wasn’t a real object creating the glow, but just reflections. I was wrong about the source. My thanks to Alex Parker for a series of tweets pointing me in the right direction as well.

The thing is, the news story played up the mysterious aspects of this event, and I took the reporter to task for not investigating it more thoroughly. It bugs me when I see reports of UFOs or the like, and no real digging occurs.

But in a sense that’s just what I did. I found my explanation, found the support for it, and figured I was done (especially since I’ve seen the Moon mistaken for a UFO before). I should’ve thought further to try to find other explanations. If I had looked at the camera more carefully I would’ve seen the LEDs, and that would’ve made this whole thing pretty obvious.

Next time, too, even if the timing is perfect (like it was for the rising Moon in the video), I’ll try to remember that coincidences happen. That doesn’t make the obvious explanation the right one. And I’ll make sure my own methodology is sound before going after someone else’s.

The Martian Beacon

This one is similar to the one with the deer and the UFO. In a recent image of the surface of Mars taken by the Curiosity rover, there was an odd flash of light that appeared to be off in the distance. I saw right away that the blip of light looked very much like cosmic ray impact—subatomic particles from space hitting the detector–which I had seen literally thousands of times in Hubble images I worked on.

Since I wasn’t familiar with Curiosity images, I asked a friend who was, and she agreed they were cosmic ray hits. Case closed, I figured. I wrote up my post, and that was that.

Except not really. Another expert on Mars hardware said it may have actually been a “light leak,” a bit of sunlight that somehow got into the camera through a hole, or crack, or seam somewhere in the hardware. He also says it may be a sharp reflection of sunlight off a glinty rock. Those are certainly plausible, though right now we don’t have enough evidence to say for sure which of these explanations may or may not be the right one.

But the point is there were other possible explanations than a cosmic ray, and I should have entertained that idea. I didn’t; I came upon a plausible solution and ran with it—and while I confirmed it (and I am not putting any onus on my friend; this is all on me), the first answer I got fed into my own bias so I didn't question it as much as I should have. And like the other story, I took the reporter to task for not looking further. Arg!

This reminds me of my favorite line in the Sermon on the Mount: “Seek not the glint in thy brother’s eye; canst thou not see the infrared LED reflection that is in thine own?”

I’m paraphrasing a bit. But either way, my apologies both to the reporters and my readers over this.

The Rock and the Skydiver

A video went viral last week purporting to show a meteoroid—the solid chunk of space debris that is called a meteorite once it hits the ground—passing by a skydiver. At first I thought it was plausible and wrote a post basically taking the tack that the video looked real (as opposed to a deliberate hoax), whether or not the object was actually a meteoroid or something else. But then more evidence built up that it really was just a rock that fell out of the skydiver’s parachute (this is surprisingly common). I wrote a second post at that point, saying I couldn’t be sure, but if I had to bet, I’d bet rock.

Then I got an email from Steinar Midtskogen, one of the people who made the video, and he was admitting they had to face the fact that it was almost certainly a rock. All well and good, but by that point I had noticed a second object in the video, which I took to be more debris falling out of the parachute. While I was pretty sure the first object was a rock by then, the second one convinced me. So I wrote a brief, final post to wrap everything up.

But then Midtskogen emailed me again, saying that they had also seen the second object, and that it was most likely another skydiver on the same jump. Oh! Well, that was certainly plausible, so I updated my post saying so.

Then confusion reigned. I got tweets and emails asking me why I still thought the first object was a rock, when it turned out the second object wasn’t a rock. So I wrote an update, pointing out that my conclusion didn’t depend on the second object, it was just strengthened by it. To me, it pushed my opinion from 95 percent sure to 99 percent, but going back to 95 percent wasn’t so bad. And again, the team had already come to the same conclusion, so I felt pretty safe in mine.

In this case, sure, I made a mistake, and should’ve examined the video more closely to see if the second object could’ve been the other skydiver (who does show up in the video). Luckily, it didn’t really matter, but it was still an error, and it caused confusion among my readers. That’s a situation I try very, very hard to avoid. These things can be confusing enough without me making them worse! I should’ve been more clear on why the second object was neither here nor there when it came to the overall picture.

The Skeptic Ouroboros

Being a skeptic is hard. It’s not easy to try to weigh evidence for everything, be methodical, critical, aware of bias, and come to a conclusion that you’re willing to drop if better evidence comes along. Worse, many times the things you are being skeptical of are cherished beliefs and values held by others, and that’s a fun little path to walk down. It can provoke some pretty, um, strong reactions in people.

But the absolute hardest thing of all is to be skeptical of your own skepticism. Did I miss something? Did I think of other explanations? Am I biased in some way, jumping to a conclusion because I think I know the answer?

How might I be wrong?

I rather blew it a few times this past week by not asking those questions. I’ve been a skeptic a long time, but this is pretty good evidence that you never perfect the technique. Being skeptical is a journey, not a destination. You just have to keep trying.

I’ll keep trying. And just to help, I’ve left myself a little note stuck to my monitor to remind me. Now I just have to remember to check it before clicking that “publish” button every day.

Maybe. That's the point.

Photo by Phil Plait. I double checked.

April 11 2014 7:45 AM

The Beauty of the Mundane

Forty-five million light years away, toward the constellation of Ursa Major, sits a rather unremarkable galaxy. It is not undergoing huge bursts of star formation. It is not blasting out radiation from its core. It isn’t twisted into bizarre shapes by the gravitational influence of a nearby passing galaxy, nor actively eating any smaller galaxies, nor swaddled in thick layers of dust.

It just is, sitting there, being a spiral galaxy. And that’s what makes it so stunningly gorgeous.

NGC 2841
The ordinary but extraordinary spiral galaxy NGC 2841. Click to galactinate.

Photo by Robert Gendler, NASA/ESA, Subaru, and DSS, used by permission


That image was created by noted astrophotographer Robert Gendler, who made it using observations by Hubble, the 8.2 meter Subaru telescope, the Digitized Sky Survey, and some of his own images. It is breathtaking in its beauty, showing a galaxy remarkable in its unremarkableness.

I wrote details about NGC 2841 in an earlier article, when the Hubble image was released. Try as I might, I found very little about this galaxy to make it stand out. It’s an absolutely normal spiral galaxy. The only even mildly unusual things about it are that it has some activity in its core that has very slightly warmed up the gas there (probably due to weak action around its central super-massive black hole) and that it’s quite large. NGC 2841 is probably about 100,000 light years across, the same size as our home, the Milky Way galaxy. It almost certainly got that size by merging with other galaxies over the eons, growing each time, but that gluttony has long since passed; NGC 2841 is now stable, quiet, and excruciatingly lovely.

There is one thing I want to point out. The arms of the galaxy are numerous and short, studded with pink gas clouds where stars are being born and larger clouds of opaque dust that block the light from stars behind them. That gives the galaxy a categorization of “flocculent,” a word I quite like.

A closer look at the dusty arms of the galaxy.

Photo by Robert Gendler, NASA/ESA, Subaru, and DSS

But it also leads to an interesting effect. In the close-up above, you can see that the dust on the near side of the galaxy (left and below the center) is more obvious and seems to fade out on the far side of the galaxy. This is due to geometry, plus the thickness of the galaxy itself.

On the near side, we have a clear view of the flat spiral disk of the galaxy. Both the stars and the dust and easily visible, the contrast high. But when we look to the far side we are looking across the galaxy itself. There are stars above the plane of the disk, and especially in the roughly spherical core of the galaxy as well. The individual billions of stars blur together to form a glow, a fuzz, and that “fills in” the dark patches of the dust on the far side of the galaxy. Just as the dust itself blocks light from stars behind it, the stars in front of the dust glow too, and make the puffy dust clouds harder to see. It’s a quick and easy trick to figure out which way the galaxy is tipped, which might be hard to determine by eye otherwise.

I have looked at and admired images of literally thousands of galaxies, and over the years I have discovered that there is no such thing as a boring one. Even the most mundane is a vast, sprawling collection of billions of stars, huge clouds of gas and dust, and structure on a scale so grand it dwarfs all of human achievements to a microscopic dot.

Nothing in nature is boring. It is a story told on the tapestry of the Universe, it is all interwoven, and the best part is that we are a part of it, and can try to understand it for ourselves.

April 10 2014 11:51 AM

Bambi Versus the Space Alien

[UPDATE (Apr. 11, 2014 at 16:00 UTC): The following post contains some corrections that I have clarified in a follow-up article. Please read that when you're done here. Thanks! -PP]

BA Tweep owlice sent me a link to a video that had me chuckling. It’s from the local Oklahoma City Fox station, KOKH, showing a Mississippi couple talking about some footage from a camera they set up outside their house. They were hoping to get a deer or two, but what they got was (cue creepy music) a UFO.


Well, kinda. Watch:

So what is it? Happily, the timeline is dramatically read by the newscaster: At 7:29 a dim light appears, at 7:35 it gets brighter, at 7:53 a weird shape appears, and then at 7:56 another sharper light appears … then it gets much closer, and finally “flies away”.

He asks, “The deer are lit up brightly. But how? The cameras are infrared and don’t emit light.”

Oh, I know how. I was literally 22 seconds into the video when I fired up my sky mapping software (Sky Safari), knowing what I’d find. Sure enough, on that date (Feb. 16, 2014) the nearly full Moon rose at the exact local time the lights were getting brighter. Being so close to full, the Moon would have been quite bright, lighting up the sky just before it rose. Once it was up it shone into the cameras, creating various lens flares, internal reflections caused by the optics. The part where it “flies away” (at 0:46 seconds into the video) is clearly a lens flare.

[UPDATE (Apr. 10 at 16:30 UTC): The plot thickens! Well, thins. Astronomer Alex Parker noted the camera does in fact give off light; it has a bank of infrared LEDs right above the lens. He's right, I totally missed that! You can see them at 1:22 into the video. These are very bright in the infrared, and are almost certainly what are illuminating the deer in the still picture I used at the top of the post—the ghostly reflection is the deer itself (though Parker notes it looks like it could be vapor from the deer's breath) and the "eyes" in the ghost are a reflection of the deer's eyes. I had assumed the Moon was doing this. I'll note the timing with the Moon rise is too much of a coincidence, though, so now I think both are at fault. The glow seen is due to the Moon, while the bright reflections are due to the infrared LEDs.

it goes to show: No good debunking goes unpunished.]

I can forgive people not familiar with the sky thinking something creepy was happening on their camera—in other words, the couple's reaction was not surprising and fairly typical, I'd wager—but it irks me to no end when newscasters run with stories like this without any skepticism about them. He (or his editor) could’ve called any number of astronomers (it was taken at night, after all), or just poked around on the Web looking for other explanations. Instead? We get a UFO.

By the way, the execrable Daily Mail credulously ran with this story too. Shocking.

I wonder though if the advent of the ‘Net has lessened the number of these kinds of breathless reports, even as individual stories may get spread wider and more quickly. I’m not sure there’s any way to tell. But as long as they keep happening, I’ll keep debunking them.

I have an odd sort of job security.

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