Bad Astronomy
The entire universe in blog form

April 11 2016 11:45 AM

Volcanic Eruption of Denial

I love the website RealClimate. Actual, working climate scientists write the articles there, and they discuss the current news about climate. They also take on the deniers, and do so in an expert and clear fashion.

I was really impressed with a recent commentary they wrote about how volcanoes are so abused by the deny-o-sphere. If you pay any attention at all to media when climate is discussed, you’ve probably heard a claim like this: “The eruption of [such-and-such] volcano put 100 times as much [pollutant or greenhouse gas] into the air as all human activity for a year!”

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These claims are dead wrong; so wrong in fact that it’s difficult for me to believe that the people making them are being honest. The RealClimate article goes into the history of these claims, which is interesting in and of itself. But what I always find fascinating is how the deniers take scientific data and then dishonestly alter them to sound reasonable.

For example, volcanoes put chlorine into the atmosphere. Deniers then compare that to human outputs of chlorofluorocarbons, or CFCs, which damage the ozone layer. But even if a single volcanic eruption put out more chlorine than human activity in a year (and they generally put out far less), the chlorine is in the form of hydrochloric acid (HCl), which is water-soluble and rains out almost immediately. CFCs are much hardier molecules and stay in the atmosphere for long periods of time. Both have chlorine, but they are very different molecules, with very different behaviors, and therefore very different effects. Comparing them is shaky at best.

I always laugh ruefully when I hear deniers talking about volcanic emission of carbon dioxide, too. They tend to exaggerate it hugely; in 2015 Mike Huckabee claimed that a single volcano puts out as much climate changing gases as humans do in a century.

That’s utter crap. Volcanoes emit about 250 million tons of CO2 on average per year. Humans emit 40 billion. Billion, with a b, more than 100 times as much as volcanoes. Even a huge, catastrophic volcanic eruption emits far less CO2 than humans do in a year. What Huckabee said was just made-up nonsense. Since he clearly has no idea what he’s talking about, yet he states it as a fact, it wouldn’t be too out-of-school to say he was lying about it.

Which brings me to the point I make over and again: If global warming is such an obvious hoax, why are deniers constantly so dishonest about it? Why not present the facts as they stand, instead of lying about them, distorting them, being misleading about them, cherry-picking them, and concocting conspiracy theories about them?

Why, it’s almost as if they have no facts, no data to back up their claims, so these dirty tactics are all they can muster.

Huh.

April 11 2016 9:15 AM

No, Planet Nine Will Not Send a Wave of Earth-Destroying Comets to Kill Us All

<sarcasm> Oh good, I get to write yet another article about factually challenged fearmongering nonsense. </sarcasm>

Sigh.

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Quite a few people on Twitter and Facebook pointed out this one to me. The guilty party is an article in the U.K. tabloid fish-wrappery the Sun posted on Wednesday. It had this breathless (and grossly ridiculous) headline: “Mysterious Planet Wiped Out Life on Earth Once and Could Do It Again THIS MONTH”.

Yeah, not so much. The article itself then goes on to make a series of increasingly shaky and completely wrong claims (what follows are direct quotations from the article):

  • “Planet Nine—a new planet discovered at the edge of the solar system in January—has triggered comet showers that bomb the Earth’s surface, killing all life, says Daniel Whitmire, of the University of Louisiana.”
  • “Professor Whitmire claims Planet Nine's passage through a rock laden area called the Kuiper Belt is responsible for the ‘extinction events’.”
  • “Now some are convinced there will be a collision or a near miss before the end of April.”
  • “Nemesis or Nibiru were widely dismissed as crack-pot pseudo-science—until Planet Nine was identified in January by the California Institute of Technology, in the US.”

These claims—not to put too fine a point on it—are 100 percent male bovine excrement.

First, Planet Nine has not been “discovered.” At best, astronomers Batygin and Brown found indirect evidence for the existence of a massive planet out past Neptune (as have other astronomers before them). It’s pretty interesting evidence, even compelling, but does not yet add up to a discovery.

Second, Daniel Whitmire does not make the claim that the planet (if it exists) causes extinction events. In a recent paper, he does a bit of math showing that the existence of a trans-Neptunian planet is consistent with the idea of periodic showers of comets raining down on Earth (more on this in a moment), but he does not claim it actually does this. I’m also not sure the planet he hypothesizes is consistent with the evidence presented by Batygin and Brown; some of the orbital and planetary characteristics are similar, others aren’t.

Third, he doesn’t say it “killed all life” on Earth, because that would be really, really dumb. Mass extinctions don’t kill all life on Earth, or else we wouldn’t be here. They kill many, even most, species, but not all. I’m not nitpicking; in an article apparently designed to instill fear, phrasing like that is important.

don't panic
Be a hoopy frood.

Shutterstock/Shay Yacobinski

Fourth, who exactly are these “some” people who claim there will be a collision in April? The article never says. Quite literally; the claim is made and then never followed up on. I could just as easily say, “Some say the author of the Sun article ate 300 puppies for breakfast”. As long as I (and one other person) says that sentence out loud it’s factually correct, though (presumably) not true.

Fifth, Nibiru was and still is dismissed as sheer crackpottery, whether or not Planet Nine exists. That’s because it is sheer crackpottery. The claims made about Nibiru are completely and utterly wrong, based on bad biblical and archaeological interpretations, and ruled out by an observational survey. But gee, other than that …

Nemesis—the name given to a purported faint and cool companion to the Sun—wasn’t a crackpot idea but has pretty much been ruled out over the years by better and better observations.

Sixth, again, Planet Nine has not been identified. C’mon.

Seventh, the basis of all this silliness is the idea that mass extinctions are periodic—that is, occur on a fairly regular cycle. But this periodicity may not even exist.

Cycles of extinctions have been claimed before, but they’re pretty hard to prove. The fossil record is spotty, and it’s hard to get absolute dates for them. There have been claims of a ~60 million periodicity too—I wrote about that one in my book Death From the Skies!, in fact. But these claims struggle with small number statistics, which can make periods look real when they’re not.

I’m not saying the periodicity doesn’t exist, just that it isn’t anywhere near confirmed yet—to be fair to the tabloid, in his paper Whitmire does claim these periodicities are firmly shown. But I don’t think that’s necessarily the case; I’m still pretty skeptical of it. Claims based on this periodicity need to be taken with a very large grain of salt.

So the article in the Sun is just a pile of steaming nonsense.

Not to be outdone, though, the New York Post—another birdcage liner—created an even more ridiculous video with unreferenced information basically lifted directly from the Sun article, but with bonus goofiness added. Like the Sun article, the video says Planet Nine was discovered in January, which isn’t true. Then it says Planet Nine takes 20,000 years to orbit the Sun (this time I mean our star the Sun, not the black hole of folderol the Sun), but again we don’t know that at all.

But wait! There’s more!

The video continues blithely on, saying, “Some scientists believe this is what caused the extinction of the dinosaurs.” Actually, no, that impact was most likely a one-off event, not part of a periodic shower of comets, and was likely aided by geological conditions at the time.

Then the video repeats (again, with no references or basis in reality) that Planet Nine may send killer comets our way this month. Worse, it mangles the previously mangled nonsense from the Sun, saying scientists (not just random "some" people) think it may happen again this month.

Bottom line: Planet Nine, as described by astronomers Brown and Batygin, is likely to exist but has not been found yet. It’s unlikely to cause periodic mass extinctions, which haven’t been shown to exist anyway. And it certainly won’t send a barrage of outer solar system ice our way this month.

In other words, don’t believe what you read in tabloids. Or anywhere, actually. Seek out the actual facts.

And I’ll add that this sort of doomsday-tooting fearmongering is disgusting. It’s irresponsible and mean-spirited. It erodes people’s understanding of science and needlessly scares people just so the paper can sell ads.

And the worst part? They’ll just keep on doing it.

I’ve written on this topic, many, many times before. Here’s a sample:

April 10 2016 9:30 AM

Welcome to the Grand Aleutian

One reason I could never be an astronaut is that all I would ever do while in space is have my nose pressed up against the window all the time. I’d never get anything done.

With views like the one above, can you blame me?

April 9 2016 9:00 AM

Time Lapse: Field of View

Y’know, every now and again you just need to sit back, breathe deeply, and watch a stunning and lush time-lapse video of thunderstorms and stars circling in the sky.

Happily, Randy Halverson has made one for you. Called “Field of View,” the three-plus minute trailer is available in resolution up to 4K, so make it big and enjoy:

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Oh, my. I love watching the stars above a thunderstorm and also the bubbling, rising currents of warm air percolating at the tops of those cumulonimbus clouds. A favorite is also to try to spot geosynchronous satellites in the views of stars; as the stars move across the screen due to Earth’s rotation, the geosynch sats look like they’re standing still in the sky.

Like I said, this is a trailer; the full-length version is available for download, as well as many of Halverson’s other lovely animations. I’ve written about them before, so have a look-see:

… and honestly so many more it’s probably just best to go to his site and take a look. You’ll be happy you did.

April 8 2016 6:15 PM

SpaceX Sticks the Landing!

Eight minutes and 35 seconds after a SpaceX Falcon 9 rocket launched into space, the first stage booster came back to Earth and successfully landed vertically on a barge floating in the Atlantic Ocean.

This was seriously one of the most amazing things I have ever seen in my life. Watch for yourself:

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Like I said. Amazing.

The previous attempts to bring the booster down at sea have met with, um, limited success, a few with what SpaceX CEO Elon Musk has called “rapid unscheduled disassembly” events. In other words, boom.

The idea behind this is that building a first stage Falcon 9 booster is expensive, but cleaning, checking out, refurbishing, and relaunching one is much cheaper. Those steps are still to come, and we’ll see what the real-world costs and testing yields. But for now, the critical first step has been taken.

booster on the barge
The Falcon 9 booster stands tall on the barge after landing. Or oceaning. I guess "barging".

SpaceX

I’ve described why this feat is so technically challenging before; the first stage booster is moving eastward at about 6,000 kph (3,600 mph) when its engine cuts off (the second stage takes over from there). The booster has to flip over, slow down, put itself on the right trajectory, come in over the floating barge, then relight its engines at just the right amount to kill its velocity and land upright. Because it’s hundreds of kilometers east of Florida by the time it starts to come back, it helps to have a landing platform out to sea to save rocket fuel. In December, the booster successfully touched down vertically back at the landing site, and this is the first time it’s been done at sea. SpaceX now has shown it has the flexibility to retrieve the booster under a variety of launch configurations.

Incidentally, the barge is named Of Course I Still Love You, after a spaceship in a novel by Iain Banks

Mind you as well, the primary mission was to launch a Dragon capsule full of supplies to the International Space Station, and that is going well right now too. The Dragon was placed in to orbit by the Falcon 9 second stage minutes after the first stage booster landed. The solar panels deployed (needed to power the capsule for its two-day journey to catch up to ISS), and it’s on the right trajectory.

Supplies on board include food, equipment, and live mice (for an experiment dealing with muscle wasting in microgravity). Also included is a bouncy castle an inflatable habitat built by the Bigelow Aerospace, literally a balloon that will be attached to a module on ISS and inflated to test how such a habitat can be used in space. They are much lighter and less expensive than building a rigid structure, and may well be used commonly in the future of space exploration.

All of this is boggling. Mind you, the last attempt by SpaceX to send a Dragon to ISS ended in the rocket disintegrating moments after takeoff when a strut broke inside the booster, causing a helium tank to explode and rupture the booster’s outer skin. There have been a few Falcon9 launches since, but this is the first to go back to ISS. And it’s on its way.

My sincere and slack-jawed congratulations to SpaceX, Elon Musk, and everyone who helped put this bird into space, and brought a piece of space history back to Earth. Well done.

April 8 2016 9:00 AM

The Delicate Petals of a 30 Megaton Impact

I’m not a geologist. I’m an astronomer, and a general science enthusiast, with an extra dollop of enthusiasm set in reserve for geology.

It’s one of the reasons I’m so enthralled with asteroid impacts. I get both astronomy and geology in one fell swoop (with a not-incidental soupçon of dinosaurs, too, for somewhat obvious reasons)!

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But, since it’s not my field, I still get baffled when I see certain things. Happily, I have a bunch of geologist friends (scientists hang out in packs) to whom I can send questions. Other times, the answer is right in front of me.

The image above is from the Lunar Reconnaissance Orbiter Camera and shows a crater on the Moon nicknamed Chappy (it formed in the much larger Chaplygin crater). It’s about 1,400 meters across (a bit bigger than Barringer crater in Arizona), which means that whatever asteroid or comet slammed into the Moon here exploded with the yield of about a 30 megaton bomb—about as big as any nuke ever detonated by humans. The fresh pattern of ejected material around it suggests a very young age. How young is hard to know, maybe only a few millennia, maybe more. But over time micrometeorite impacts and the solar wind soften and fade those features, so the crater isn’t, say, millions of years old*.

The pattern around Chappy shows broad, wide streaks, seemingly overlapping with streaks of different contrast, looking very much like the petals of a flower.

detail
Detail of the ejecta near the crater.

NASA/GSFC/Arizona State University

It’s that lovely pattern that got me thinking. Sometimes craters have rays, thin, long, linear features that can extend for thousands of kilometers in bigger impacts. Rays are caused by plumes of material ejected from the impact event; the material blasts outward then settles onto the surface making the radial streaks.

When the Moon is full, the huge crater Tycho shows prominent rays, one of the more iconic features on the Moon. I’ve seen it and them hundreds of times through my own telescope, one of the few really interesting features visible when the Moon is full.

That biased me. I’ve written about craters that have these broader petal patterns before, ascribing to them the same formation mechanism as rays: collapsing plumes from the impact.

But that’s wrong. In the LROC blog post about the image, they give the correct mechanism: ground flow. Material blasted out from the impact flowed along the lunar surface, hugging the ground, moving up and down over the hummocky surroundings, and flowing around or deflected by obstacles. That also explains the shapes of the petals; the endpoint of each (the terminus) is where the material stopped flowing, either as momentum was lost due to friction or the material simply ran out. Some flows are thicker, some less dense, which can give them different brightnesses on the ground.

When I read that, I almost slapped my forehead. Of course those can’t be from plumes that traveled up and away; the shape is all wrong. But I was prejudiced from what I already knew, not thinking there could be other mechanisms at work.

more detail
More detail: note how the flow goes up and down over the terrain.

NASA/GSFC/Arizona State University

I urge you to subscribe to the LROC images blog; they post truly beautiful and fascinating images taken by the camera, with a description written by someone familiar with the data. It’s a seemingly endless source of wonderful science.

P.S. At the bottom of their Chappy post is an interactive widget where you can scan, pan, and magnify the terrain around Chappy, and it’s incredible. Go.

* Update, Apr. 9, 2016: Or is it? I got a note from planetary scientist Clark Chapman about this, and he correctly pointed out that Tycho is probably 100 million years old and still has obvious rays, as I actually mention in the article. So having bright ejecta patterns is not necessarily the indicator of extreme youth I thought it was. Now I have to start looking into why Tycho's rays are still so bright after such a long time...

April 7 2016 9:00 AM

A Hundred Billion Galaxies

Perhaps you’ve heard that there are a hundred billion galaxies in the Universe. That’s a soul-crushing number, so vast and unreachable that it’s literally hard to believe.

Let me make a believer out of you.

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That photo above is from the venerable Hubble Space Telescope. It’s part of a colossal effort by astronomers, dubbed the Frontier Fields program, to peer as deeply as possible into a half-dozen galaxy clusters, veritable cities of galaxies that can contain thousands of galaxies like our own. The combined gravity of these clusters can bend light, which magnifies and amplifies the light coming from even more distant galaxies on the other side of the cluster from us. This “gravitational lensing” allows us to see fainter, more distant galaxies than would be possible without the clusters' aid.

Clusters are where galaxies are more common … but the image above does not show such a cluster. Hubble is a single telescope equipped with several cameras. Each camera sees a slightly different part of the sky when Hubble is pointed at a target. Two main cameras were utilized for Frontier Fields: the Advanced Camera for Surveys (or ACS), and the Wide Field Camera 3 (WFC3).

For this image, the cluster Abell 2744 (also called Pandora’s Cluster) was the main target, and was being observed by WFC3. At the same time, ACS was viewing the nearby part of the sky shown above.

As you can see, it’s filled with galaxies. I scanned the full resolution 6,750 x 6,500 pixel image, and only found a dozen or so objects I could unambiguously identify as stars (point sources like stars get those cross-shaped diffraction spikes through them; extended objects like galaxies smear out the spikes so they become invisible).

In other words, for all intents and purposes, every object you see in that photo is a galaxy, each a sprawling collection of gas, dust, and countless billions of stars, each thousands or even hundreds of thousands of light years across.

I have two points to make here.

Swimming in Sculptor
A semi-random subsection of the big image. How many galaxies do you see?

NASA, ESA, and the HST Frontier Fields team (STScI). Acknowledgement: Judy Schmidt (Geckzilla).

First, note how few of the galaxies have what you might think off as overall structure. Sure, many are lens-shaped, spiral, elliptical; but the vast majority are distorted, irregular, peculiar. I would venture that most of these objects you can see are billions of light-years away, so far away that the light we see from them left them when the Universe was far younger. When we look at the nearby Universe, many galaxies do have overall structure, obviously so. But in the distant Universe, things were different.

This right away tells you a fundamental cosmological truth: The Universe changes. It was different when it was younger.

This is a critical piece of evidence that the Universe began. It had a start. It’s one of the many, many pieces of evidence strongly supporting the Big Bang model of the origin of the cosmos. There may have been something out there before it, but what we see now reflects what happened then.

My second point is somewhat more prosaic, though no less profound.

How many galaxies are in this image? Counting them is a daunting task, so I made it simpler on myself: I looked a series of 650 x 675 pixel subsections, and counted the galaxies in each of them. Since the full image is 10 times bigger on each side, the average number of galaxies in each subsection should be 1/100th the total in the image.

I found very roughly 50 identifiable galaxies per subsection. That means the image contains roughly 5,000 galaxies.

The image itself is a tiny, tiny slice of the sky, only a little over three arcminutes on a side. An arcminute is an angular measure of size; there are 60 arcminutes in a degree. The Moon on the sky is about half a degree across, so you can see this is indeed a small piece of cosmic real estate.

There are about 41,000 square degrees in the entire sky, which in turn means there are 41,000 x 60 x 60 = about 150 million square arcminutes in the sky. The image above is about 10 square arcminutes, so it would take 15 million such observations to cover the entire sky.

Perhaps you see where I’m going with this. If there are 5,000 galaxies in the image, and it would take 15 million such fields to cover the sky, then there must be about 5,000 x 15 million = 75 billion galaxies visible in the sky. At least; some will still be too faint to see even in this Hubble image.

Now do you see? Just by taking this observation and applying some high school math, we have discovered that the Universe has something like a hundred billion galaxies in it.

And each of those galaxies has billions of stars. That means there are something like a sextillion stars in the Universe: 1,000,000,000,000,000,000,000 suns.

And it’s reasonable to think that most of those stars have planets, perhaps multiple planets. How many are Earth-like? How many have life?

And yet, in all that—and perhaps more—there’s only one planet just like Earth, only one of all of us. One of you.

Look back at the image taken by Hubble. Look at it closely. The Universe is so vast it may be impossible for us to grasp its size and scale; yet by studying it, by embracing it, we see that our being a part of it is special.

If there is one most amazing thing that astronomy, that science, has shown us, I believe it is that.

April 6 2016 11:45 AM

Soon

Soon.

And yes, those are my goats. That's Sam standing on my daughter's back, and Clayton plotting world domination behind him.

April 6 2016 9:00 AM

A Distant, Moody Comet

I just thought y’all deserved to see this stunning and moody portrait of the comet 67P/Churyumov-Gerasimenko, taken by the Rosetta spacecraft on March 27, when it was about 329 kilometers away from the comet’s rocky and icy solid nucleus.

Although it looks like the Sun is directly behind the comet, it’s not quite; the angle from the spacecraft to the comet to the Sun is about 160°, with the Sun off the frame above and a bit to the right. You can see the lit “crescent” comet, its two lobes mostly backlit. Vents in the surface are warmed by the Sun, and ice there sublimates, turning directly into a gas, expanding, and blowing away from the comet. That’s what forms those lovely fanlike jets of material.

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Some of the jets look curved, and I suspect that’s due to the rotation of the comet; the material flung away moves in a straight line, but as the comet spins, each particle is flung away in a slightly different direction, creating curved or spiral patterns. This is called the “sprinkler head effect” and is seen in many objects, including comets, stars, and even rocket flights.

To give you a sense of scale, the big lobe of the comet is about 4.1 kilometers across, and the smaller one about 2.6 kilometers. The jets fan out, and eventually become the comet’s coma—the fuzzy cloud around the solid nucleus—and the tail.

This image was taken specifically to study the material around the comet; it’s a relatively long four-second exposure, and the camera was set to be more sensitive to light to capture faint details. And yes, I’m pretty sure those are actual stars in the background. This really is quite a lovely picture.

After several months of close passes, Rosetta was recently sent on a long-distance excursion that went to 1,000 kilometers from the nucleus to study the space environment surrounding the comet now that it’s passed its closest point to the Sun and is moving outward again in its orbit. The spacecraft is on its way back to the comet now, and will pass just 30 kilometers over the surface in a few more days—this is referred to as a “zero phase flyby,” which means the Sun will be shining directly down on the comet from Rosetta’s view (I wonder if the spacecraft might even see its own shadow, which it’s done before, though it may be too distant for the shadow to be clear).

It’s nice to see Rosetta still performing well. But not for much longer: The end of the mission is planned for September 2016, when the spacecraft will be commanded to land (hopefully gently) on the comet’s surface.

But that’s months away, and there’s much more to be learned from this spectacular and frankly weird object as it heads away from the Sun and its warmth, back into the colder depths of the solar system past Mars and Jupiter.

I wonder … the comet orbits the Sun every six years or so. Will we ever venture back? Will future robots, or even humans, come to find Rosetta resting on the comet’s surface, dusty and frosty from the constant exhalations of the active object? It’s a nice thought. I hope so.

April 5 2016 12:00 PM

Time Lapse: “Radiance”

If you’ve been reading my blog for any amount of time at all, I really shouldn’t need to do any urging to get you to watch a gorgeous time-lapse video of aurorae.

So, here:

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Breathtaking. There is something particularly striking about the luminescent purple and green aurorae together that demands my attention. And the ending! Lightning storm with aurorae! Wow.

The photography is by Shawn Malone of Lake Superior Photo. Funny; I lived in Michigan for three years and never saw an aurora. But maybe the lights of Ann Arbor are too bright.

As for the aurora itself, they’re caused when the Sun floods interplanetary space with subatomic particles in the solar wind. These are channeled down into or atmosphere by Earth’s magnetic field, causing the air to glow depending on what atom or molecule is energized by the event.

I have a page full of links to explanations about aurorae if you want to learn more. And you should; I find it very pleasing that such interesting scientific phenomena can produce such displays of utter, pure beauty. When I see something like this—sheets of glowing filaments, flickering colors, draping waves of light—I want to know why. And when I find out, the depth of my appreciation grows.

As Carl Sagan said:

It is sometimes said that scientists are unromantic, that their passion to figure out robs the world of beauty and mystery. But … it does no harm to the romance of the sunset to know a little bit about it.

I think Sagan could have gone farther. I would have added, “… and in fact, it enhances its majesty greatly.”

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