Bad Astronomy Blog
In mid-October, the comet C/2013 A1 (Siding Spring) will have a very close encounter with Mars. It will pass just over 130,000 kilometers from the Red Planet; while engineers have been working to make sure our spacecraft are safe from debris, scientists are eager to gather data about the comet using those same spacecraft.
In the meantime, the comet has become a favorite for astrophotographers, because it’s relatively bright and has been passing by one astronomical gem after another. Marco Lorenzi is one such astrophotographer. He has a remotely operated observatory outside of Coonabarabran, Australia, and on Aug. 30, 2014, took this stunning shot of the comet as it passed by one of the most beautiful objects in the sky: the globular cluster 47 Tuc.
Crikey! 47 Tuc is one of the largest globulars in the sky, a million or so stars packed into a sphere held together by their own gravity. You can spot a few other clusters dotting the images as well.
Lorenzi had to be a bit tricky to get this shot. The cluster requires long exposures, but during those the comet moves so much it would get smeared out. So he took a series of long exposures for the cluster and short ones for the comet, combining them in such a way that it faithfully represents what the scene looked like (the method he used is outlined here). Clever.
And, of course, quite beautiful. Incredibly, I had to shrink it to fit the blog; click it for the full 2,200 x 2,200 version. And even then, Lorenzi told me this is only a small part of the full frame he took! Yikes.
I suspect I’ll be running more pictures by him in the future, because wow. In the meantime check out some of the other amazing pictures he’s taken. You won’t regret it.
Over the past year or so, I’ve written a few times on how the “polar vortex” — actually, deep meanders or excursions in the usually stable west-to-east direction of the polar cyclonic air stream — may be tied to global warming, but there hadn’t been enough research done yet to be sure.
Well, here we go: A team of Korean and American scientists has made the connection. Warmer waters lead to more melting of Arctic ice, which destabilizes the polar jet stream. My Slate colleague Eric Holthaus has an excellent write-up of it, and I wanted to give him a signal boost here. Go read it.
I want to add a few points. One I already made above: What people have been calling the “polar vortex” is not really the polar vortex. There is a stable flow of air (that’s the polar vortex) going around the poles, at higher latitudes than the jet stream. Technically a cyclone, it wanders and wiggles from a perfect circle, but sometimes will have deep excursions, bringing frigid Arctic air to lower latitudes. Those excursions are what hit the US several times in the past year.
When this happens, the excursions can become somewhat stable themselves. This prevents the normal circulation of air around the globe, so they’re called “blocking patterns”. That’s what was responsible for the tremendous heat wave Alaska suffered in January 2014. Over a year ago, in June 2013, Alaska had a persistent high pressure system squat over the state, and the year before that a similar system caused a massive melting in Greenland.
I mentioned at the time the idea that global warming may be affecting weather patterns, and of course the denial Noise Machine kicked into gear; I got a lot of comments and tweets mocking the idea.
Now, though, we have this new research upholding that conclusion. I’m not surprised. We know that global weather patterns depend on a lot of factors, but the amount of available heat — thinking of it as fuel might help — is a critical one. If you crank up the planet’s thermostat you don’t just make the climate hotter, you make it unstable.
It’s like driving a car. A lot of factors have to balance for a safe drive: how much gas you give the engine, friction with the road, road surface conditions, weather, and so on. Step on the gas and you don’t just go faster; all those factors play in, and it gets harder to control the vehicle. A small gust, a slick patch of highway, a pothole; their effects all get amplified. When you hit the gas too hard you’re in for a very terrifying out-of-control ride.
And here we are, pedal to the metal.
The result? Extreme weather is becoming the new normal, with droughts in some places, flooding in others, strengthening tropical cyclones on the Atlantic, loss of polar ice, oceans acidifying, and more.
So while the Mail Online and Wall Street Journal continue to post ridiculous denier talking points, the world continues to heat up. I’ll note that the US has done almost nothing about this, and that is almost entirely due to Republicans in the House and Senate. I’ll also note we have an election coming up, a very important one. Get the facts (I suggest starting here and here), and keep them in mind when you hit the polling booth this November.
Hot on the heels of the incredible volcanic explosion video I posted recently comes another in the “holy cow these things really exist?!” department: a volcano tornado.
Yes, you read that right. OK, technically, it’s a vortex, more like a dust devil than a tornado. Still.
Nicarnica Aviation is a company that has created infrared cameras that can detect volcanic ash in the air as a safety measure for pilots; ash is composed of microscopic particles of rock that are very jagged, and can clog airplane engines. Wanting to avoid that while you’re in the air should be obvious enough.
One of Nicarnica’s cameras was set up near the erupting Bardarbunga volcano in Iceland, and on Wednesday, Sept. 3, they caught the hephaestean twister:
That’s amazing. It’s also not entirely unprecedented! In February 2014 a series of twisters arose from pyroclastic flows blasting down the slopes of the volcano Sinabung in Indonesia, and they’re also somewhat common in big fires (like here and here). In April, a fire in Australia generated an amazing one that lasted for quite some time.
This is the first one I’ve seen over lava, though. I suspect the physics behind it is the same as the others, though. As I wrote before:Now technically these aren’t tornadoes, even if they look like it. Tornadoes are when a funnel cloud is connected to the ground at its bottom and the base of a cumulonimbus cloud at its top. They form from the top down, dropping from the cloud base. In this case, though, the phenomena are built from the ground up. The pyroclastic flow [Or in this current case, lava] heats the air over the ground, causing it to rise. Air from the sides then rushes in to fill the partial vacuum. This creates swirls, eddies of turbulence, which can get amplified into the vortices seen in the video (and also in fire tornadoes which are also seriously a thing). This makes these events more like a dust devil than proper tornadoes. Or, I suppose, an ash devil. But still, yeesh.
In this case, the volcanado (yes, I’m calling it that, and yes, SyFy: Call me) is loaded with ash noxious gases like sulfur dioxide. Nasty.
But also amazing. I think this technology to spot the ash is important, too. Iceland is situated upwind from much of Europe, and as we learned in 2010 with Eyjafjallajokull, that can cause quite a mess with air travel.
Tip o’ the caldera to New Scientist.
As I do every year on this day: Wear flared off-white polyester pants, go outside, face where the Moon used to be before it blasted out of Earth orbit, and pour out a drop of wine on the ground for the 311 lost souls of Moonbase Alpha.
I can’t believe it’s been 15 years now. I miss seeing Eagles soaring in the sky above.
The European space probe Rosetta has been hanging out with the comet 67/P Churyumov-Gerasimenko since early August. Initially at station-keeping about 100 kilometers away, it’s now dropped down to less than half that. In November it’ll release the lander Philae to set down on the comet, and scientists are deciding now just where to put it.
In the meantime, Rosetta is snapping away, taking a lot of pictures and data. And the comet hasn’t been quiet: A jet of gas has formed coming from the neck region!
That image above was put together by my friend Emily Lakdawalla, and I leave it to her capable keyboarding to describe how she made this image and to give details of the science.
However, I want to add that the jet is very interesting. ALICE, an ultraviolet detector on board Rosetta, has been taking observations and found very little water ice on the surface of the comet. That’s a bit surprising, since we know comets tend to have lots of ice in them. However, ALICE did see oxygen and hydrogen surrounding the comet. That means there’s water ice under the surface, and it’s getting out. I have to say, that jet seems the likely source.
Unlike asteroids, the surfaces of comets constantly change, especially when they near the Sun. It gets warm enough to turn ice into gas, which then blows away in jets and forms the fuzzy coma surrounding the solid nucleus. That’s why the surface of Chu-Ger doesn’t look like an asteroid; the impacts aren’t as obvious when the outer layers get resurfaced all the time. Also, the comet isn’t solid, like a chunk of rock, but more likely crunchy. Impacts won’t leave your more typical-looking craters in that sort of material.
This is all very exciting! We’ve flown missions past comets before, many times, but this is the first time a probe has stuck around. The comet is slowly approaching the Sun in its orbit, and will reach its closest—and therefore warmest—point in its orbit around the Sun next August. Rosetta’s mission isn’t scheduled to end until a few months after that, so it’ll ride the comet down and watch as activity returns to this dirty snowball. And we get to ride along and watch the whole time too.
Tl;dr: Buy this book.
Randall started a second Web comic–like series called “what if?,” where he answers readers’ weird questions by extrapolating the science as far as (and, many times, quite a bit farther than) it will go. The answers are always entertaining, funny, and display a sort of naked curiosity on Randall’s part I really admire.
So with all that, I was of course happy he decided to take the best ones and compile them with all new ones to create a book called What If: Serious Scientific Answers to Absurd Hypothetical Questions (available in hardcover and on Kindle). It’s loaded with really great stuff, including:
- What happens if you pitch a baseball at 90 percent the speed of light? (bad things)
- What happens if you had a mole of moles? (also bad things)
- What would happen if a glass of water were literally suddenly half empty? (sorta bad things)
- How fast can you hit a speed bump and still live? (pretty fast)
… and tons more.
Look, I answer questions for a living, too, and Randall is really, really good at this. He finds weird little scientific ways to answer the questions, but it’s his extrapolations that kill me. I laughed a lot reading this book. Even better: I learned stuff reading this book. And you will too.
So stop reading my blog, buy the book, read it, and then start reading my blog again. In that order. Go.
Hey, remember that SciShow video I posted about, when I visited the adorable Hank Green in Montana and filmed a short thing with me talking about the smallest star in the Universe?
While I was up there, Hank and I sat down to do a short conversation to promote Comic Relief, a charity that’s raising money to help educate (and feed) kids in Zambia.
Hank and I talked distance. Specifically, how do you figure it out? Stars are far away, yet we seem to be pretty confident when we give their distances. It turns out, the answer is right in front of your nose. Watch.
That was fun! And Hank was honestly excited about the topic, and the very fact that we can know what we know. That’s one of the reasons I like him.
If you want more info on the topics we discussed, I’ve written about parallax and also on how exploding stars are used to gauge the expansion of the Universe.
Also, as you saw in the opening part of the video, this was done to raise money for kids in Africa, which is pretty cool by me. As it says in the YouTube video show notes:Help more students learn, by giving to Comic Relief at http://www.comicrelief.com/SOYT
Or if you’re in the US, you can text SOYT12 to 71777, message and data rates may apply.
If you’re in the UK, text SOYT12 to 70005. Texts cost £5 plus your standard network message charge. £5 per text goes to Comic Relief. You must be 16 or over and please ask the bill payers permission. For full terms and conditions and more information go to www.comicrelief.com/terms-of-use
Because stars may be far away, but no one on Earth really is. Help ‘em out if you can.
One of my favorite pastimes is to simply drink in the scenery on long drives or as I bike around the countryside. You never know what you might see, what spectacle might present itself.
For Rosetta the situation is very similar … except when you’re a spacecraft hundreds of millions of kilometers from Earth, slowly approaching a comet, the scenic overlook may prove just a tad more dramatic:
That shot was taken by the Comet nucleus Infrared and Visible Analyzer, or CIVA, camera on board Rosetta’s Philae lander. The lander is still mounted to the spacecraft, so in this shot you can see Rosetta’s solar panels and part of the main spacecraft body.
And just above hangs the target of the mission: the comet 67P/Churyumov-Gerasimenko. With the Sun far below, the double-lobed comet is lit incredibly dramatically, each half of the comet a ragged crescent. From 50 kilometers (30 miles) away a lot of features can be seen, but this view is soon to get substantially better: In November, Philae will touch down on the surface of the comet, and the pictures we’ll get from this camera will show up close and personal the bizarre, alien landscape of this tiny world.
Episode 3 of the Slate Plus Doctor Who podcast is now live, where my editor Laura Helmuth and I talk about “Robot of Sherwood.” At the risk of spoilers, I, um, didn’t like it as much as previous episodes. And by “previous episodes,” I mean all of them, dating back to “Rose.”
I won’t go into it here but instead point you to the podcast where you can hear us grumble about the episode. It wasn’t all bad, but I was hoping for a lot more.
Still, I love Doctor Who, despite the odd road bump or two. And I’m still excited for the rest of the Capaldi episodes!
And as I’ve said before:Fair warning: The podcast is part of Slate Plus, which is a premium subscription service. It’s five bucks a month and provides all kinds of fun added content; I’ve written about it before. There’s a lot of great stuff there on top of the usual great stuff at Slate, so I heartily recommend signing up.
My good friend, Amy Davis Roth, is awesome.
Or, more properly, awe-inspiring. On her own she is quite a person: A dedicated artist who produces cool jewelry, who creates wonderful paintings, who is an outspoken supporter of critical thinking and science, and who is also an intelligent, thoughtful, and vocal feminist.
She does all this — and much more — every single day while slogging through an unbelievable miasma of misogyny.
And I do mean unbelievable. For having the temerity to say that women should have equal rights, opportunities, and treatment as men, she gets a tsunami of hatred, venom, death threats, rape threats, and more. It would be enough to break down hardened people, and it has. But not Amy. She manages to not only deal with this horrifying onslaught, but also turn it into art.
I mean that literally. With the help of several other atheist and skeptical women, Amy has created an exhibit called A Woman’s Room Online: a free-standing 8x10 foot room that is being installed in the LA Center for Inquiry office. It will look superficially much like any office in which a woman might work, with the usual accoutrements.
But each object will be covered with messages these women have received on Twitter, Facebook, and email. Real messages, actual things sent to them that are the vilest, most hateful examples of the worst humanity has to offer.
I recently visited Amy and stayed with her for a few days. She showed some of the individual pieces to my wife and me, and they are as powerful as the words plastered on them are repellent.
The words are hard to read, so difficult to imagine an actual human sending them to another human. They run the range from self-satisfied and arrogant to graphic and explicit threats against body and life. Sexism and misogyny had been brewing in the atheist and skeptical movements for some time, but exploded when Rebecca Watson brought attention to them, and people were further polarized after Richard Dawkins made his “Muslima” comments in response. That was years ago, and things are no better... as we've also seen in so many other online communities as well.
Perhaps sunlight is the best disinfectant, and art has a way of focusing that light. Over at Skepchick, Amy herself wrote a description of her installation, and I strongly encourage you to read it.
I think this is an important piece of art. I suspect a lot of people really don’t have any idea just how much filth women (not only feminists, but just women on the internet guilty of Posting While Female) have to slog through every day just to exist online. It’s horrifying — and sadly, used as a way to shut women up; read Amanda Marcotte's recent post about this.
A Woman’s Room Online will hopefully open a lot of eyes. And minds. And, hopefully, hearts.
The exhibit opens this weekend, running from Sep. 13 – Oct. 13 daily. For more information, contact the LA Women’s Atheist and Agnostic Group (a group Amy founded, and they're accepting donations through there as well).
You can follow Amy on Twitter, and you should.
Global warming is real. Climate change is occurring faster than any time in recorded history. Humans dumping carbon dioxide into the air is to blame.
In the scientific community, those statements are not controversial at all. A solid 97% of climate scientists doing active research into the matter agree on them.
Politically, though, it’s a different story. Only about half the American public think global warming is man-made, and only a fraction of them know that there is overwhelming scientific consensus on it.
To raise both ratios, the wonderful website Skeptical Science has started a great campaign: “97 Hours of Consensus”. Every hour, for just over four days, a cartoon caricature of a different climate scientist will be posted along with a short, pithy quotation about the current understanding on global warming. The campaign started Sunday morning (Sep. 7), so it’s well along now. It started with Dr. Michael Mann, creator of the Hockey Stick graph showing that sudden warming is recent and catastrophic:
The images are free to use under Creative Commons, so I suggest doing so. Spread them far and wide. Get the word out: The science is in, and the temperature is up. We must get people to understand it… especially in an election year.
Stories are coming out of Managua, Nicaragua, that a large bang was heard by residents there Saturday evening, and it registered on seismic detectors as well. A crater was found in the woods measuring something like 12 meters (40 feet) across. Claims are being made that this was a meteorite impact, a space rock a meter or so across slamming into the ground at high speed.
… but I’m unconvinced. Reports are still a bit sketchy, but my biggest doubts come in two parts:
1) In a city of over two million people, you’d expect a fireball around midnight would’ve been seen by a lot of people. I haven’t heard any confirmed reports of witnesses. Also, I haven’t seen any video from it either. The situation in Chelyabinsk in 2013 was different, of course, but video of that event showed up with an hour or two. I’d expect that after two days we’d have some visual evidence from Managua by now.
Note: I’ve already seen a video on YouTube claiming to be from the fireball, but it’s not; it’s a bright meteor that came in over Spain. Don’t be fooled by hoaxes! There are always lots of them when something like this happens. The picture at the top of this post appears in a lot of hoaxes; it was from a fireball over the Netherlands in 2009.
b) No meteorite has yet been found. If this was an impact, there should be debris in the crater, at the very least on a microscopic scale. I haven’t heard of any analysis of the soil there to look for fragments, either.
I am not saying this was not a meteorite impact. I am saying the evidence for this that I’ve seen so far leaves me pretty unconvinced. I’ll note this happened near an Air Force base, too, which again makes me a little more suspicious.
So my skeptic sense is tingling here, and won’t be assuaged until we get much better evidence than has been reported so far. I’ll add that some places are reporting that this may have been connected with asteroid 2014 RC, which passed by the Earth on Sunday. Although this was a near miss (2014 RC got less than 40,000 km from Earth) I am very, very doubtful of a connection. The asteroid passed at 18:00 UTC Sunday, which was noon Nicaragua time: 12 hours or so after whatever happened in Managua. It’s incredibly unlikely that a small piece of that asteroid was that far ahead of the main mass and still managed to hit us. The asteroid was moving at 40,000 kilometers per hour, so it was still farther away than the Moon when this event occurred.
Bottom line: This may or may not have been an impact from a meteorite. At the moment, based on what I’ve seen so far, I’d bet against it… but I’ve been wrong before. Until I see confirmed video or actual confirmed meteorite fragments I’ll remain doubtful.
If there’s one star in the sky people know about, it’s Betelgeuse*.
Marking the right shoulder of the hunter Orion — remember, he’s facing us, so it’s on our left — this orange-red star is one of the brightest in the night sky. It’s been studied for as long as we’ve had telescopes, yet for all our advanced technology and knowhow, details about it are maddeningly vague. We don’t even have a good determination of how far away it is!
Still, there’s a lot we do know: It’s a red supergiant, a star that started out life already a lot bigger, more massive, and far more luminous than the Sun. Stars like that go through their nuclear fuel extremely rapidly; while the Sun is only approaching middle age at 4.5 billion years old, Betelgeuse is dying now at an age of less than 10 million years old. And when it does finally give up the ghost, it’ll do so with a bang. A very, very big bang: It’ll go supernova, one of nature’s most dramatic and ridiculously violent events.
But when? A lot’s been written about that. If you believe pseudoscientists and crackpots, you might have thought 2012 was our last chance to see it. Sometimes the news spreads that it’ll go any day now. Somehow, oddly, despite all that nonsense you can still see Betelgeuse shining in the sky.
However, the thing is, it really will explode one day. We don’t really know when, exactly, which is why I usually hedge my bet by saying it could be tonight, but more likely it’ll be hundreds of thousands of years from now… a million years, tops.
As a scientist, that date range is a little bothersome. That’s why I was delighted to read a research paper trying to nail down this very fact. While it’s still a bit iffy, and details are still elusive, the astronomers who did the research were able to make a much more refined prediction: Betelgeuse will go boom in about 100,000 years.
Wow. That’s sooner than I would have thought. It’s still a long way off, of course, but in a galactic sense that’s a blink of the eye.
This prediction depends on a lot of things, so the astronomers had to make determine many basic facts about the star as best they could (generally depending on the previous work of others). It’s all pretty amazing, so let me list them out for you with brief comments:
Distance: Betelgeuse is likely to be about 200 parsecs (650 light years) away. Different methods yield different distances, which has been frustrating, but a recent paper gives what may be this best result.
Age: Models of the star’s evolution over time yield an age estimate of about 8.5 million years. That’s a bit older than I would have expected, but quite reasonable. Compare that to the Sun’s age of 4.56 billion years, and you’ll see why I say stars like Betelgeuse don’t live long!
Mass: The best estimates of the mass of Betelgeuse give about 20 times that of the Sun (more or less). That’s a lot; as you get more massive, stars get more rare, and only a handful get this hefty.
Radius: This is where we start getting into “yikes” territory: Betelgeuse is a staggering 890 (± 200) times wider than the Sun! Bear in mind the Sun is over 100 times wider than the Earth and you may realize what a behemoth this star is. That’s a radius — a radius — of over 600 million kilometers! Replace the Sun with Betelgeuse, and it would stretch nearly to the orbit of Jupiter. The Earth would be engulfed.
Rotation: Stars tend to rotate slowly. When they expand, as Betelgeuse did long ago, they slow down (this is called conservation of angular momentum, like when an ice skater draws in his or her arms and spins more rapidly). Betelgeuse is huge, so unsurprisingly it spins very slowly, only once every 8.4 years. The Sun spins about once a month, for comparison.
Luminosity: Betelgeuse is bright. It shines with the energy of 125,000 times that of the Sun. Holy wow. That’s why it can be hundreds of light years away and still be one of the brightest stars in the sky. At that distance, you’d need a telescope to see the Sun at all.
Mass loss: When massive stars use up the hydrogen fuel in their core, they start to fuse helium into carbon. This generates a lot of heat, which causes the outer parts of the star to expand (hot gases expand, after all). Betelgeuse is pretty bloated, which means gravity at its surface is pretty weak. The star is also incredibly luminous, so a gas molecule on its surface feels a strong outward force from the light, and only a weak force from gravity holding it down. The result: Betelgeuse blows a very strong wind of material away from it. It loses about a millionth of the mass of the Sun every year. That may not sound like much, but the Sun loses less than a trillionth of its mass every year. Betelgeuse blasts out a million times as much material as the Sun. That’s not a solar wind. It’s a gale.
The supernova: Using all these data, plus what we know about how stars evolve over time, the astronomers find that in about 100,000 years, Betelgeuse will run out of helium to fuse. The steps after that are a bit complicated, but essentially, it will begin to fuse ever-heavier elements on ever-shortening timescales, until it tries to fuse silicon into iron. This spells doom for the star, because it robs the star of the energy needed to support itself. The core collapses, heats up beyond imagining, and explodes. KaBLAM! No more Betelgeuse.
The aftermath: First, repeat after me: WE ARE IN NO DANGER, EVER, FROM BETELGEUSE.
At that distance, even the titanic detonation of a supergiant star poses no major threat. It’ll be bright, as bright as the full Moon! But it’s too far away to hurt us. Also? 100,000 years is a long time.
Mind you, it’ll launch octillions of tons of matter into space in all directions at a decent fraction of the speed of light. But as it plows through the thin soup of stuff in space it’ll slow down. The astronomers in the paper estimate the shock wave will take six million years to reach us, and will be moving at a mere 13 kilometers per second. It’ll slam into the Sun’s outgoing solar wind, and the two will wrestle, but the shock itself will stop well outside the Earth’s orbit.
But holy cow, that’ll be a show. But you’ll have to wait a hundred millennia for the opening curtain.
I’m not that patient. Statistically speaking, a galaxy hosts a supernova every century or so. The Milky Way hasn’t had one pop off for a long time, so we’re bound to get one sooner or later that we can study. We may get a thousand or so before Betelgeuse finally loses it. Some will almost certainly even be closer than Betelgeuse is. Again, we’re in no real danger from a nearby supernova, and it would be nice to see one at a relatively proximate distance. Oh, what we’d learn!
…but poor Orion. Once Betelgeuse goes, and fades away over a few months, he’ll be missing his right shoulder. I wonder what myths we’ll have to modify to accommodate for that?
Tip o' the neutrino detector to Tod Lauer.
What Is the Nearest Star to Earth That Can Go Supernova?
[But bear in mind: The Closest Supernova Candidate?]
Betelgeuse Blows Out a Monstrous Arc of Gas Nearly As Big As Our Solar System
Betelgeuse Is About to Hit the Wall
Is Betelgeuse About to Blow?
Betelgeuse and 2012
* OK, fine, a lot of people know Polaris, too. And I guess, if you want to be picky, they’ve heard of the Sun as well. But still. Betelgeuse!
Today — Sunday, Sep. 7, 2014 — at about 18:00 UTC, a small asteroid named 2014 RC will harmlessly pass by the Earth, though at the close distance of very roughly 40,000 km. I wrote all about it a couple of days ago… and also warned that you can expect a bunch of breathless and fact-free YouTube videos about it, claiming it would hit us.
I was so, so close.
The very day I posted that, a ridiculous article appeared in the UK tabloid Express, claiming that the Earth “faces 100 YEARS of killer [asteroid] strikes starting 2017.”
How do I phrase this? That claim is really really really really really wrong. Really.
The author of this article, Nathan Rao, has a history of writing reality-impaired articles; for example, in August he wrote a piece suggesting the Supermoon might kill everyone on Earth. This led to a less-than-satisfying exchange of tweets between Rao and me (and many others), with him trying to defend his writing, and ended with me telling him, “Whatever helps you sleep at night.”
Anyway, this asteroid article he wrote is more of the same. Essentially the only time he gets anything right in that piece is when he quotes some astronomers, but the conclusions he jumps (leaps, launches, hyperspace blasts) to are way, way off the mark.
For example, he claimsA previously unknown asteroid belt has been located in deep space and is now hurtling towards our part of the solar system […] The terrifying predictions came as NASA revealed disturbing new data showing 400 impacts are expected between 2017 and 2113, based on new observational data of objects seen in space over the past 60 days.
Um, no. Not even close. It’s not an asteroid belt, but a single asteroid. And it’s not 400 impacts, it’s 400 predicted passes of Earth, most missing by a wide margin.
Happily, UK amateur astronomer David Wood (who also sent me the note notifying me of Rao’s article) did the footwork for me. He figured out that Rao is talking about the asteroid 2014 NZ64. It fits Rao’s (bizarrely interpreted) description; it was recently discovered (in July, about 60 days ago) and the JPL Earth Impact Risk Summary page has a list of 399 near-Earth passes between the years 2017 and 2113, the exact range Rao listed. It’s obviously what Rao is talking about, but somehow Rao turned a single asteroid that will miss us into hundreds of asteroids that will all hit us.
That’s a somewhat significant error to make.
So what’s the science here? NZ64 is a small, 100-meter or so wide asteroid that has an orbit that does take it pretty close to Earth. Since its discovery it has only been observed a handful of times, and as I’ve written many times before, the fewer observations you have, the harder it is to predict where the asteroid will be in the future. Given that, at this time, NZ64 has only been observed over less than a two-day timespan, I’d say trying to figure out where it’ll be more than a few months in advance is nearly impossible.
So bear that in mind with the Risk Impact page (which is automatically generated); we really don’t know where this asteroid will be more than a few years in the future… and since Earth is small, and space is very, very big, I’d be willing to bet the chance of an impact will get even smaller once a better orbit is determined.
Even so, take a look at the Risk Impact page, and you’ll see a column there labeled “Impact Probability”. This gives the fractional chance of an impact at every given encounter, where 0 is no impact for sure, and 1 would definitely be an impact. Note how close to 0 the numbers are! Typical values translate into odds of about a billion to one — even the wildest Vegas spender wouldn’t take that risk — and the highest chance I saw was for a pass in 2023, when it has a one in six million chance of hitting us. I have a hard time working up a sweat over that. Note also that each listed probability is actually a link where the numbers are literally spelled out for you, right there for everyone and anyone to see.
That's the central premise of Rao's article, and it's clearly wrong.
I could stop there, but there's one more I'd like to point out. He writes,Asteroid 2012 DA14, discovered by astronomers at the LaSagra Observatory in Spain, currently has less than a one per cent chance of hitting but scientists can't rule out the possibility that it might smash into our planet.
Actually, that is precisely wrong: DA14 was taken off the impact risk list months ago, after observations ruled out any chance of impact in the near future.
Normally I would ignore nonsense like Rao’s article, but I decided to write about it when I saw his piece was relatively popular on Facebook (though the comments there are pretty funny, as most of the commenters fully grasp the, ah, tenuous reality of the article).
Also, to put it mildly, I take a dim view of articles that spin, fold, and mutilate science, doubly so when it’s astronomy on the wrong end of it. And at the very least, this is a chance to show folks how this whole process of flagging asteroids works, so some good can come of it.
But it also shows that, once again and as always, you can’t believe everything (or anything) you see online (and I certainly would be extremely skeptical of anything I read in the Express). When it comes to things like asteroid impacts, your best bet is to check with JPL, or — ahem — here. If an asteroid has a decent chance of hitting us, I’d write about it… after getting confirmation and as many facts as I could from people who actually understand asteroid science.
This has to be seen to be believed: An Australian couple vacationing in Papua New Guinea heard that a local volcano, Mount Tavurvur, had been erupting. They got on a boat to take a closer look, and got the ride of their lives (make sure you’ve set the video to HD, the detail is amazing):
Holy yikes! The video was taken by Phil McNamara, and posted on his wife Linda’s Facebook page. The volcano has been pretty active historically and has caused a lot of damage; it’s killed many people, and buried the nearby town of Rabaul in ash in 1994. Rabual used to be the provincial capital of the island of New Britain, but after that eruption the capital was moved to another location.
This eruption was smaller in comparison, but holy cow. It was still amazing. In the video you can see lava blasting upward hundreds of meters, falling apparently slowly due to distance. Given the timing delay of the shock wave — 13 seconds or so — so the folks on the boat were just over 4 km away (2.5 miles).
You can see the shock wave traveling down the volcano slope at 00:13, and then ramming the air above the volcano a few seconds later. The sudden compression condensed the water vapor in the air, so you can see ephemeral clouds forming in a rough circle above the explosion. I looked carefully but saw no sign of it traveling across the water.
The volcano has been spreading ash across the island, as you can see in this photo taken by Landsat 8:
On NASA’s Earth Observatory page they have a before-and-after shot, and you can see that what’s now brown and ash-laden was green just a few months before.
Looking at all that and reading about this volcano, I’d say the McNamara’s were pretty dang lucky. This explosion could’ve been a lot worse, and as it is they got some fantastic footage and a great story to tell
Tip o’ the caldera to about a hundred people who sent me this, but the first was Nathanial BB.
Perhaps you’ve heard of Hank Green; he and his brother John make videos on YouTube. Lots of videos, covering a million different topics. They do too many things to adequately describe here; you can get a taste at Hank’s site, and at John’s. Be prepared to give it a few hours, since the Vlog Brothers are something of a juggernaut online.
They put together a great science video series called SciShow, where different hosts talk about various fun and fascinating topics in science. It’s short, simple, and really well done, which is why I was more than happy to do one when Hank asked. It’s called “The Smallest Star in the Universe”, and it's live on the SciShow Space channel:
Nifty! Mind you, I did not write the script; it was penned by Sarah Willis, a postdoctoral researcher at the Center for Astrophysics who also does a lot of public outreach. I did a very small amount of editing on the script, but she did all the heavy lifting. If you want more info on this, I wrote about the star J0523 on the blog when it was announced awhile back.
I had a lot of fun making this video. It was also terrific to get to know Hank and his team; Hank is precisely as nice as he seems. It’s always truly uplifting to meet people who are firing on all cylinders. I had the same feeling after meeting him and his crew as I do when I leave Comic Con: Inspired. Smart, creative people who actually go out and do stuff really motivate me to fire up my brain and start doing things.
As I write this, SciShow has just under two million subscribers on YouTube. I bet BABloggees could push that a lot closer to the 2M mark. Go subscribe! You’ll get more science in your life, and that’s always a good thing. And while you’re at it, if you liked it please give my own video a thumbs-up. You can support SciShow at Subbable, too.
The other day, I posted a picture of the Earth from space, sunrise over a blue planet, saying, “Sometimes, you just need to be reminded that our planet is a beautiful place to be.”
Did I write “beautiful”? I meant magnificent.
That stunning portrait of our planet was taken by Russian astronaut Oleg Artemyev, who is currently on the International Space Station. Looking toward the horizon and using a telephoto lens, the perspective is compressed and you can see hundreds of kilometers of cloudscape in one go.
The depth of the image is incredibly compelling, both seeing the clouds shrink with distance as well as the feeling of height into the atmosphere. And to top it off—literally—the subtle play of blue air fading into the black of space forces you to see that this picture was not photographed anywhere near the comforting climes of home.
I’m currently wrestling with a large number of deadlines, tasks both minor and huge, and the next few weeks feel like an oily miasma enveloping me. But then I see something like this, and it’s a mental jolt, an almost electric change of state in my brain. My mind is filled with awe, and suddenly my own pressing needs have their edges softened, their jagged corners rounded.
Sometimes we need to take a step back (or up) and see the bigger picture. It may not cure the immediate ills we face, but it certainly helps put them in perspective.
On Sunday, Sep. 7, 2014, Earth will get yet another close shave from an asteroid. This time it’s a rock called 2014 RC, and it’ll blow past us at about 18:00 UTC (2:00 p.m. Eastern), missing the planet by something like 35,000 km (22,000 miles).
2014 RC was discovered just a few days ago, on Sep. 1. Given its distance and brightness, it’s probably about 20 meters across — the same size range as the Chelyabinsk asteroid that blew up over Russia in February of 2013.
To be clear: It’ll miss us. We’re safe. But it does get pretty close, about the same distance as orbiting geosynchronous weather and communication satellites. Even though it’s bigger than those satellites, it’s very faint; the prediction is it’ll be about 11th magnitude, or about 1/100th the brightness of the faintest star you can see with your unaided eye. It’ll take a decent-sized telescope to spot it*.
This is all a reminder that these things do whiz past us fairly often, and even if they’re big enough to do damage should they hit us, we generally don’t get a lot of warning beforehand. Asteroids like this are just too faint. Happily, they don’t hit us very often.
Still, at the very least, we need bigger ‘scopes for asteroid searches. We’re doing pretty well in that department, with Pan-STARRS, and the LSST (which is still some years away from operating). But even then they can’t cover the whole sky, which is why I support the efforts of both the B612 Foundation and NASA’s NEOCam. A lot of science will come from these missions at the very least, and who knows? If they do spot a rock with our name on it, at least we’ll get the chance to do something about.
* I expect there will be hastily thrown-together YouTube videos about this asteroid that will overabundantly use the word “sheeple”. You can safely ignore them. Always.
Tip o’ the Whipple Shield to Ron Baalke and BABloggee Douglas Troy.
Last week, I hosted the first episode of a podcast series to discuss the new season of Doctor Who.
Episode 2 is now live, and I’m joined by my guest Mac Rogers to investigate what it’s like to go “Into the Dalek.” We talk about Daleks as enemies, the Doctor’s new brain, and my favorite moment of the show, when Clara [redacted] the Doctor right on the face.
Remember, this is part of the Slate Plus premium subscription service, which has lots of fun extras. Join up, and get in on the fun.
When I was a kid, playing with my fellow nerdlings, we used to try to come up with the most specific address we could for ourselves — including the whole Universe. It would go something like this: “Phil Plait, 123 Main St., Springfield, Virginia, United States of America, Earth, Solar System, Orion Spiral Arm, Milky Way Galaxy, Local Group, Virgo Supercluster, Universe.”
It looks like we can now add another locality, squeezed in between the last two: Laniakea (la-NEE-uh-KAY-uh I think is pretty close to how you pronounce it), a galactic supercluster. The folks involved put together a video explaining it, which may help before I launch into my own discussion of it:
So, let me back up a sec. The address locations I mention above are obvious enough up to the solar system. The Sun is located in what’s called the Orion arm in our spiral-armed Milky Way galaxy, which itself is part of a collection of a few dozen galaxies called the Local Group (we’re the biggest, along with the Andromeda galaxy). This ragtag group is on the outskirts of much bigger cluster of galaxies, called the Virgo Cluster, which has over a thousand galaxies in it and is several million light years across.
That in turn is part of an even more ridiculously huge structure called the Virgo Supercluster, which contains several clusters (including, perhaps confusingly, the Virgo Cluster; these get their names from their locations on the sky). Superclusters are among the largest scale structure in the Universe, spanning over a hundred million light years.
Mapping our local supercluster is rather difficult. First, it doesn’t really have a defined edge like a solid planet; it just kinda fades out with distance, until the next supercluster comes along. Also, you need to get the three dimensional location of the galaxies around us, which also presents difficulties.
However, work done by a team led by astronomer Brent Tully has done just that. They used radio telescopes to observe thousands of galaxies in the local Universe. As the Universe itself expands, it carries these galaxies away from us, and their radio waves (as well as all light they emit) loses energy — this is very similar to the more familiar Doppler shift. Astronomers call this loss of energy “redshift”, and the farther away a galaxy is, the higher the redshift is.
But if galaxies are clumped together closely in space they’ll orbit each other, or at least their mutual gravity will affect their motion. This in turn affects the redshift for each galaxy on top of the cosmic expansion. We know pretty well how the Universe is expanding on local scales, so if you subtract that part away, what’s left is the local motion of the galaxies. That can be used to map how gravity of other nearby galaxies is affecting them. This let them make a map of the density and movement of galaxies in space.
That, finally, means they could map where all these galaxies are in the Universe. They found that the Virgo Supercluster, our old home, is actually part of a bigger structure they named Lanikea, which apparently is Hawaiian for “immense heaven”. No arguments here*! Laniakea is about 500 million light years across, a staggering size, and contains the mass of 100 quadrillion Suns — one hundred million billion times the mass of our star. That’s a lot of mass.
The border of Laniakea isn’t well-defined, but the astronomers decided how to get a sense of it: its gravity. Put a galaxy near Laniakea; if it falls toward the supercluster then it’s inside the border; if it falls away toward some other supercluster than it’s outside. As definitions go it’s not so bad. It’s not the be-all-end-all; as another astronomer points out in the Nature news article, it doesn’t tell you what the eventual fate of the supercluster is (which depends on its mass and size). Like most definitions, it depends on the question you’re trying to answer. In this case, it’s more of a guideline than a definition, and I’m OK with that.
Astronomy is both ennobling and humbling. It tells us our place in the Universe, which can make you feel small… but don’t forget that we’re a part of that Universe, and the fact that we can figure this stuff out at all makes us very big indeed.
* I’ve also seen it translated as “immeasurable heaven” which means more or less the same thing colloquially, but also has an ironic ring to it, given that measuring it is exactly what we’re doing.