Bad Astronomy
The entire universe in blog form

March 31 2015 2:59 PM

Watch Me Live Tuesday Night With Felicia Day Talking about Fortune’s Pawn

I’m pretty excited to let y’all know that I’ll be a guest on the Vaginal Fantasy Book Club!

Yes, you read that right.

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It’s a video hangout/podcast hosted by Felicia Day, Bonnie Burton, Veronica Belmont, and Kiala Kazebee, where they drink wine, talk about a romance-fantasy novel they’ve read, and make dirty jokes. I haven’t met Kiala yet, but I have ridiculous crushes on Felicia, Bonnie, and Veronica (psssst: Don't tell them, because I don't think they know), so when Felicia asked me, the outcome was inevitable.

The book we’re discussing is called Fortune’s Pawn, by Rachel Bach. It’s actually a science-fiction novel, kinda sorta military in nature, about a mercenary named Devi Morris who shoots bad guys. It was a good read, brisk and fun. There is some sciencey stuff in it, which, I imagine, is why Felicia asked me in; I’m not usually much of a romance novel kinda guy, unless spaceships or aliens are involved.

The live hangout will be at 7 PT today, Tuesday, March 31 (02:00 UTC Wednesday morning). Assuming the software gods smile, the hangout will be embedded below so you can watch it live here. I expect there will be some amount of swearing and drinking (not necessarily in that order), and some sexy subjects discussed, so this'll be NSFW. Fairly warned be ye, says I.

If not, then try the Vaginal Fantasy playlist at YouTube, or on the Vaginal Fantasy site. They also have a group on Goodreads, and of course they’re on Twitter.

This’ll be fun. I don’t get to let loose very often, and I really have a lot of respect and love for these women. I hope you'll join in.

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March 31 2015 7:18 AM

Mercury: How Much More Black Can It Be?*

Mercury is an airless rocky world, much like our Moon, but for some reason it reflects less light than the Moon. This lower reflectivity (what we science types call its albedo) makes it darker than expected.

For a long time, it was thought that small grains of iron were the culprit. Being near the Sun, Mercury is cooked by light and subatomic particles from the Sun. This creates these tiny iron grains from iron embedded in the surface material, and these grains are quite dark. However, it turns out there isn’t enough of them to explain why, on average, Mercury reflects half the light the Moon does.

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A new study has turned up a new perp: carbon. Comets have lots of carbon in them, and as they swing by the Sun they release a lot of it into space. In fact, as they get closer to the Sun they release more (especially ones that disintegrate completely, which does indeed occur often), so Mercury should get a big dose of carbon.

To test this, the scientists used a powerful gas gun at NASA’s Ames Research Center (my old pal Pete Schultz is a co-author on this study; we used that gas gun for an episode of Bad Universe). They shot pellets at several kilometers per second into a target of dark basaltic rock that also had sugars mixed in it (as a carbon source, mimicking carbon-based molecules in a comet). They found that carbon could be freed from the sugar molecules and mixed into the resulting melted impact material, making it darker.

The basaltic rock was more like the Moon’s surface than Mercury, but the results are encouraging. My very first thought about this as I read the report was, “What about a spectral signature of carbon?,” meaning that if carbon were there on Mercury’s surface, why don’t we see it in spectra (breaking the light up into thousands of individual colors, allowing the chemical composition to be determined)? They covered this as well: The spectrum of the impacted material in the experiment was fairly flat, with no real hint of carbon embedded in it. The carbon was mixed into the material in a way that hid it spectroscopically, even though it absorbed light and darkened the rock.

Is this why Mercury is darker than expected? Maybe. More tests and observations are needed; the lack of a spectral signature is interesting but not in itself proof. Still, it’s kinda neat to think Mercury might be dark because it’s painted with carbon atoms, airbrushed over the eons by the breath from comets.

The surface of Mercury may be harsh, but maybe it got that way poetically.

*None. None more black.

March 30 2015 12:17 PM

BA Video: Attack of the Waterspout!

A couple of weeks ago, a waterspout formed off the coast of a tropical beach in Brazil. The panic it evoked was merited … kinda sorta. Here’s why:

I’ve seen dust devils in person many times (driving from California to Colorado years back, we saw a half dozen, one that was so big we were kilometers away when we first spotted it), and pictures of them on Mars(!). But I’ve never seen a tornado in the wild myself, or a waterspout … or an ash devil, or a fire tornado.

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Y’know what? I’m not too upset by that. Watching them on video is just fine by me.

March 30 2015 7:00 AM

The Top of the World Sinks Ever Lower

Ever year around the end of February, after a long winter, Arctic ice reaches its maximum extent. This year that happened around Feb. 25, when it encompassed 14.54 million square kilometers of ice around the North Pole.

Sound like a lot? It’s not. Really, really not. This year’s maximum extent was the lowest on record.

ice extent
Ice extent (area covered at least 15 percent by ice) for 2015 (solid blue line) compared with 2012 (dashed) and the average from 1981–2010 (black line).

Diagram by the NSIDC

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The plot above shows the situation. The solid line shows the average ice extent over the year (measured from 1981–2010) and the gray area represents a statistical measure of random fluctuations; anything inside the gray is more or less indistinguishable from the average (in other words, an excursion up or down inside the gray area could just be due to random chance).

The dashed line was the extent in 2012, when unusual conditions created the lowest minimum extent in recorded history. The solid blue line is 2015 so far. As you can see, it’s already reached maximum, and it’s well below average. It’s also outside the gray zone, meaning it’s statistically significant. It’s the earliest the peak has been reached as well. Both these facts point accusingly at global warming—more warmth, and shorter winters.

We have to be careful here, because individual records can be misleading. The trend is what’s important. However, the trend is very, very clear: Ice extent at the North Pole is decreasing rapidly over time. Note that this record low extent is about 1 percent lower than the previous record … which was last year.

The implications of losing Arctic ice are profound. First, high latitudes are more affected by warming; the temperature trends in the extreme north are twice what they are at lower latitudes.

Melting ice does contribute to sea level rise, though not as much as melting glaciers on land. The bad news: Those glaciers are melting faster than ever. This has a second effect that may prove just as disastrous, too. All that fresh water dumped into the salty ocean changes the way the water circulates around the world. This circulation is one of the key ways warmth gets redistributed around the planet. Disrupting this cannot possibly be good news for us. You can read more about this at RealClimate, and climatologist Michael Mann discussed it in a recent interview.

At the other pole, Antarctic land ice is melting at a fantastic rate, and the slight increase in sea ice is not even coming close to making up for it. Deniers love to point at the sea ice, but that comes and goes every year and is roughly stable; the land ice is melting away at huge rates. Claiming global warming is wrong because Antarctic sea ice is increasing is like pointing toward a healing paper cut on your finger when your femoral artery has been punctured.

Arctic ice is like the fabled canary in a coal mine; it’s showing us very clearly what we’re in for. And what’s headed our way is a warmer planet, an even more disrupted climate, and a world of hurt if we do nothing about it.

March 29 2015 7:15 AM

Crash Course Astronomy Outtakes

When you watch an episode of Crash Course Astronomy, you no doubt marvel at how clearly cut, professional, and perfect it is. The thing is, what you don’t see are the 18 bazillion times I stumble on a word, say things out of order, realize the grammar is wrong, and so on.

Happily, or embarrassingly, we get a lot of that stuff on camera. A Crash Course tradition is to gather those outtakes every 10 episodes and create a blooper reel. My editor, Nicole Sweeney, was maybe a little too gleeful to do this. But she did, so here you go: the Crash Course Astronomy outtakes from our first 10 episodes.

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A lot of folks were asking what I’m doing with my left hand at the end of many of the takes. I’m scrolling through the teleprompter control, resetting it to start again with the line we’re recording. These lines are hard enough to say without a teleprompter!

And oh my word how much do I love Thought Café's title graphic for this episode? If you don't get it, this may help. Next week we’ll start up once again with our regular episodes. Until then, I will endeavor to continue to screw up my lines.

March 28 2015 7:15 AM

Like Tears in Rain: Our Scars on Mars Fade

When the Curiosity rover landed on Mars, it wasn’t alone. On its way in it also dropped its heat shield, its backshell and parachute, and the rocket-powered sky crane.

That last piece of hardware was pretty much what it sounds like: A platform that used rockets to hover over the surface of Mars, lowered the rover down, then blasted away to a safe distance once Curiosity was firmly down. The sky crane rose in a parabolic arc, then impacted the ground, hard, about 650 meters away. It was still moving horizontally, so it left a blast pattern on the surface, blowing the dust away off the ground. The dust is brighter than the rock beneath, so it left behind a dark splash pattern.

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That was about 2½ years ago, and Mars hasn’t sat still. Weather and winds have beaten at the marks left by Curiosity’s accoutrements, and they’ve faded with time. JPL just released this amazing animation composed of images taken by the HiRISE camera on Mars Reconnaissance Orbiter, showing the erosion of the marks over time:

Photo by NASA/JPL-Caltech/University of Arizona

As you can see, the marks have faded, most likely gradually being covered over by dust. The other pieces of hardware show similar changes (though less dramatic, given their smaller impacts)—you can watch the animations for the heat shield, the backshell and parachute, and the rover landing site itself (of course, Curiosity has long since left; it’s a rover).

It’s not as simple as fading, though; the marks from the sky crane have also recently darkened. It’s not clear why, though it’s possible dust blew in, then blew out again. We’ve seen the dust on Mars has done more elaborate and weirder things.

This is more than just interesting: We’re gearing up to send more probes to Mars, and eventually people. Understand the Martian weather will be critical. The dust is extremely fine, like talcum powder, and made of iron oxide: rust. It will get into everything (it coated Opportunity’s solar panels, reducing power until strong winds cleaned it off later). Understanding the dust transport mechanisms will be crucial for living on Mars as well.

And since you’re here, why not: Back when the landing took place, YouTube user Dominic Muller created an amazing video using images taken from the descent camera on the sky crane; he used a technique called interpolation to smooth out the video, and if you haven’t seen it (or it’s been a couple of years), watch it! It’s quite remarkable.

March 27 2015 7:00 AM

The Year of Living Weightlessly

Update, March 27, 2015, at 20:00 UTC: Success! The launch was on time and flawless, propelling the astronauts to orbit. They are scheduled to meet up with the ISS at 01:36 UTC tonight.

Today, at 19:42 UTC (3:42 p.m. Eastern U.S. time), astronaut Scott Kelly and cosmonaut Mikhail Kornienko will ride a Soyuz rocket to the International Space Station. This isn’t an ordinary mission: They will stay aboard ISS for a year, twice as long as the usual NASA expedition length. The purpose is to study long–term effects of microgravity on the human body, to learn more for a possible trip to Mars.*

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Expedition 43, as this one is numbered, has a number of different research directions, including seeing how the lengthy flight affects behavior, physical function, eyesight, metabolism, and more—things we know are affected by prolonged low-gravity conditions.

The reasoning behind this makes sense; a long flight to, say, Mars will seriously hamper astronauts’ ability to move around once they land.

I’ll note this isn’t the longest time people will have spent in space; two Russians spent more time on the old Mir space station, and two others spent a year on Mir as well. But this will still be pretty interesting from a biophysical point of view. A lot of work has been done in this field, of course, but having two people up that long at the same with consistent tests should prove helpful.

Not only that, but Kelly has a twin brother who will stay on Earth to provide a control group of sorts. His brother, Mark, is also an astronaut (the only siblings who have both been in space) who is married to ex-congresswoman Gabby Giffords. Quite a family.

I wonder what the outcome of this mission will be. It may show us that long-term space flight is too debilitating; if that’s the case, then we may need to take seriously the idea of rotating structures to mimic gravity. Those are more expensive and have to be big to avoid the spin making astronauts dizzy. I’d love to see some of those built to test out how well humans can perform on them. I’m sure either way it will help inform longer space missions.

Personal opinion time: This mission is also being billed as a precursor to flights using the Space Launch System with the Orion capsule, a future I think is a dead-end for NASA. SLS is far, far too expensive and NASA doesn’t have the budget to make it sustainable. There are serious concerns that building it will cost so much that there won’t be money left for actually using it.

I agree with space activist and writer John Strickland on this; Scientific American put up an editorial about this one-year mission, and Strickland left a comment there. In it, he wrote that for the same money SpaceX could deliver a lot more. The Falcon Heavy rocket demo launch should happen later this year; I’d like to see that go successfully first before speculating any further. But it does seem like the right move for NASA. I have very serious doubts about SLS.

Anyway, I expect the Soyuz launch of the Expedition will be covered on NASA TV and its Ustream channel. I’ll be watching live, and tweeting about it too.

* Also riding on the rocket will be seasoned cosmonaut Gennady Padalka, who will not be staying for the entire duration of this extended mission.

NASA has a peculiar numbering convention for ISS missions. A new Expedition starts when three of the six crew members on board leave (officially when the door to the return capsule closes), so Expedition 43 started in early March, and there are now three people on ISS. Kelly, Kornienko, and Padalka will join 43 already in progress. The three on there now will leave in May, and that's when Expedition 44 starts. Kelly and Kornienko will stay through Expedition 46, overlapping with the crews from the other Expeditions.

March 26 2015 7:00 AM

The Catastrophe That Must Not Be Named

By now you may have heard that Florida Gov. Rick Scott is a flat-out global warming denier, even though his state is arguably the most vulnerable to sea level rise and other problems that are surely to come if we do nothing.

But even doing nothing is too much for Scott. Four former officials at Florida’s Department of Environmental Protection have claimed that Scott put out an unwritten rule ordering that no one at the DEP even use the phrases global warming or climate change in any of their communications.

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There has been some back and forth in various media about whether this was true or not—it’s hard to prove an unofficial decree—but then this video has come along, which pretty much confirms the order was real. It shows Florida’s emergency management director Bryan Koon testifying to the state Senate about receiving funds from the Federal Emergency Management Agency (which has threatened to deny some funding to states with climate change–denying governors). During the Q&A, Sen. Jeff Clemens (D–District 27) has some fun at Gov. Scott’s expense.*

Koon’s visible discomfort during this whole thing makes it pretty clear what’s what. It would be almost painful to watch … except for the obvious delight of the other senators, who cannot stop laughing at the whole ridiculous mess.

I’m glad they recognize that. The rest of the country, the world, is laughing at their governor’s denial of reality. The problem is laughing won’t change their minds, or get these head-in-the-sand politicians voted out of office … or will it? A majority of voters think climate change is an issue we need to deal with, including Republican voters. If those voters go to the polls and make that stance clear, then maybe those politicians would figure out that all that Koch brothers money won’t help them get re-elected.

Our changing climate needs to be an issue voters take seriously. What starts with laughter now will hopefully turn into the good kind of change later: changing who’s in office.

*Correction, March 26, 2015: This post originally misspelled Florida state Sen. Jeff Clemens’ last name.

March 25 2015 7:00 AM

Did Jupiter Destroy the Solar System’s First Planets?

Our solar system is weird.

First of all, it doesn’t look much like other ones we’ve been finding. A lot of those have Jupiter-size giant planets orbiting very close in to their parents stars (“hot Jupiters”), closer even than Mercury orbits the Sun. By contrast, our Jupiter orbits the Sun much farther out, more than a dozen times Mercury’s distance from the Sun.

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Worse, a lot of these other solar systems are compact. They have several planets orbiting close in to their star, and these planets tend to be “super-Earths,” bigger than our home world but smaller than Neptune. They probably have thick atmospheres, too. A good example of this is Kepler-11, which has six planets that orbit their star inside the size of Venus’ orbit.

So why are we so different than everyone else? The answer may be: Jupiter. A new paper has been released that points an accusatory finger at our solar system’s largest world. Ours may have looked a lot like all the others we’ve seen, but Jupiter came along and wiped it out, setting the stage for what see today: lower mass worlds like ours close in, and bigger ones farther out.

Here’s how this works. When the solar system was very young, just a few million years old, it was basically the Sun in the center surrounded by a huge disk of gas and dust. Jupiter formed probably not too far from where it currently is, a few hundred million kilometers out from the Sun … but it didn’t stay there.

Its gravity interacted with the material in the disk around it. The overall effect of this is to cause Jupiter to start moving inward, migrating toward the Sun. It continued to interact with the disk material, including with actively forming bodies that may have been many kilometers or even hundreds of kilometers in size. It would send them inward, crashing into the Sun. As much as 10–20 times the Earth’s mass worth of material could have been wiped out this way by the time Jupiter got to about 230 million kilometers from the Sun (very roughly where Mars is now).

Something stopped its inward movement at that point. The culprit here is Saturn; models have shown that Saturn and Jupiter would also interact gravitationally through a process called a resonance; Saturn repeatedly tugged on Jupiter, pulling it back out of the inner solar system, placing it where it is today.

When it was all done, there was far less material close in to the Sun than there was initially. The inner planets we see today, Mercury, Venus, Earth, and Mars, formed from whatever stuff was leftover, which wasn’t much.

The idea of Jupiter’s migration has been around a long time, but this new model of how it interacts with the disk explains a lot of the weirdness we see now—including why our planets are smaller than we tend to see in other systems (because of the paucity of material from which they formed). The inner planets are thought to have formed as late as 100–200 million years after the solar system got started, and this explains why, too. They formed after Jupiter bullied its way through the system.

It’s also consistent with the existence of hot Jupiters; in other solar systems where a massive planet like Jupiter forms, but no second, slightly less massive planet outside it like Saturn forms, there’s nothing to reverse the course of the bigger one. It keeps moving in until it destroys the inner disk; at that point it stops migrating and you’re left with a system with a big planet orbiting close in.

Kepler-11
The Kepler-11 exoplanet system compared with ours. Did we used to look like this? It's entirely possible.

Photo by NASA/Tim Pyle

And here’s a very cool thing: We think super-Earths may form easily and quickly in solar system like ours, perhaps as rapidly as a million years. That may have even happened in our own solar system. But when Jupiter moved in it would have disrupted the orbits of those planets, dropping them into the Sun. If they once existed, they don’t now! Jupiter wiped the slate clean. Then our familiar planets formed later.

Imagine how different our solar system would look if Jupiter hadn’t formed, or Saturn hadn’t reined it in.

The beauty of this model, too, is that it doesn’t just explain what we see, it also makes predictions. For example, if we see an exoplanet system with lots of close-in super-Earths, we should not expect to see a Jupiter-size planet farther out. If it were there it should’ve wiped out the inner planets. If there is a Jupiter-size planet farther out, you should expect to find 1) a second massive planet outside the first, but slightly less massive than the first (if it’s more massive, then it becomes the one to control the situation), and 2) smaller planets like ours in the inner region, not super-Earths. Or maybe nothing at all, if all the material got wiped out.

We’re not quite at the stage yet where we can go through the exoplanets catalog and check that statistically, but we’re getting there. A new planet-finding orbiting observatory is in the works called TESS, which should yield huge numbers of such solar systems, allowing us to check the hypothesis. The Kepler mission, which discovered more than 1,000 planets, has been retooled and may also provide data to confirm or negate this study.

Oh, how I love this. This idea is still just a hypothesis, but it appears to be a good one, and better yet, it can be tested. And here’s the best part: By studying other solar systems, we learn more about ours. An example of one is a poor sample; you need many more to compare and contrast. The early discovery of hot Jupiters threw our ideas of planet formation for a loop, and then super-Earths messed with it more. But we use that data in planetary diversity to expand our models, refine them, and come to a better and greater understanding of ourselves.

Huh. Sounds like a pretty good lesson to me.

March 24 2015 12:26 PM

Sen: Ancient Radioactive Lunar Volcano

For my fortnightly column at Sen.com this go-round, I had a lot of fun writing about an ancient lunar volcano’s explosive eruption eons ago, the extent of which was mapped using gamma rays from radioactive thorium buried under billions of years of impact-produced lunar dust.

So yeah, I had a lot of fun. Sometimes just researching an article is pretty cool.

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As I’ve said before, while the news and other sections at Sen are free, the blogs are subscription only. But if you look at the bloggers there, you’ll find that the price is totally worth it. You’d spend more than that on a book by just one person. And for that you’ll get to read lots of people covering lots of space. Literally.

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