Bad Astronomy
The entire universe in blog form

May 20 2016 8:45 AM

Of Course Trump Chose a Global Warming Denier as His Energy Adviser

Donald Trump has announced his new energy adviser: Rep. Kevin Cramer (R–North Dakota). 

I hope you’re sitting down for this shocker: Cramer is a global warming denier. And to be clear, he’s not just a denier. He’s a crackpot.

First, watch this video put together by the folks here at Slate to get an overview of this guy’s view on science:

Trump’s grave misunderstanding of the difference between weather and climate doesn’t surprise me; he’s a buffoon when it comes to such topics (case in point: he said global warming is a hoax manufactured by the Chinese). Given his history, his choice of a crackpot for energy adviser isn’t terribly surprising.

North Dakota fracking glows at night
If you don't remember any big cities in North Dakota that could glow like that at night, it's because that's not a city. That's the light from huge numbers of fracking sites burning off excess gas.

NASA Earth Observatory/NOAA NGDC

Cramer has a long record of climate change denial (apropos of nothing, over his career Cramer has received more than a half million bucks in funding from the fossil fuel industry, more than twice as much as any other industry). That’s also not surprising given that North Dakota is one of the largest producers of oil and coal in the nation. The burning of excess natural gas fracked in the state is so intense it’s easily visible to satellites in space. Given all that, Cramer denying climate change is de rigeur.

It’s the degree (so to speak) to which he denies it that’s staggering. He’s part of the tiny, tiny head-in-the-sand deniers who won’t even acknowledge the planet’s heating up. That line in the video where he says, “We know the globe is cooling; number one we know that” is from 2012, just a few years ago. We’ve known since long before then the planet is heating up, and the past few years the warming has gone into overdrive; each of the past seven months have been the hottest of those months globally. To actually say out loud that the Earth is cooling would make Orwell blush.

But he wasn’t done; he also added, “… the idea that CO2 is somehow causing global warming is on its face fraudulent.”

Holy. Baloney. He’s not just denying global warming, he’s denying a link between carbon dioxide and the planet’s increasing temperature. For the record, carbon dioxide being a greenhouse gas has been a matter of scientific fact since 1896.

The conservative party really is conservative. When it comes to science, Trump and Cramer want to wind the clock back to the nineteenth century. At least.

Cramer has made it clear that if Trump gets elected, he’ll be no friend to the environment, rolling back regulations and reversing the Clean Power Plan. Trump himself has said he’ll back out of (or “renegotiate”) the Paris climate treaty, a claim he makes based on 100 percent utter nonsense.

It couldn’t be more clear: If Trump does indeed take the White House our planet is, basically, screwed.

So, there you go. Nothing about this is at all surprising from the candidate who put away the dog whistle years ago, bringing out into the open the contempt he has for women, people of color, Muslims, gays, decorum, facts, and science. This is what the modern GOP hath wrought, and come November, hopefully they’ll reap what they’ve sown.

Update, May 20, 2016: Due to a production error, an incomplete version of this post was originally published.

May 19 2016 12:00 PM

Cards Against Humanity Just Paid for a Young Woman’s College Tuition

In April 2015, I wrote about a new expansion pack for the ridiculously popular game Cards Against Humanity. The new pack was the brainchild of Zach Weinersmith, who asked me to help come up with some of the funny science-based questions and answers to the party game.

That was an easy decision on my part, but it was made even easier because the CAH folks decided to take all the money—yes, all of it—that was made from the science pack and create a full-ride scholarship for young women attending college for a STEM (science, technology, engineering, and math) degree. This is a fantastic cause and something that can really help address the imbalance between men and women in STEM.

The call went out for video submissions, and more than 1,000 young women applied. The panel of 60 professional women in STEM went through them, and they have announced a winner: Sona Dadhania, a freshman at the University of Pennsylvania! She wants to study nanotechnology, and she put together this video as her submission:

Nice! She’s a freshman now, so CAH will pay for her tuition for the next three years (a sum of about $150,000). You can read more about her in an article on As for how she reacted to the news, well, see for yourself:

Yes, that may have choked me up just a little. I’m so happy for her, and proud of my friends for what they’ve done here.

But they’re not done here! The pack has so far raised more than $880,000—yes, you read that correctly—to help women get a STEM degree. That means there’s plenty left over for more scholarships, and applications for Round 2 will be opened this fall. Stay tuned.

Congratulations, Sona! Go make the world a better, cooler, and smarter place. And, y’know, just throwing this out there: The science pack is available at the CAH online store. If you already bought one, then thanks. Look what you helped do!

Tip o’ the Erlenmeyer flask to my friend Kim Arcand.

May 19 2016 9:00 AM

White Spots Blemish the Face of Ceres

A new image of the protoplanet Ceres from the Dawn spacecraft caught my attention recently. It shows the western rim of a crater called Azacca (named after the Haitian god of agriculture; Ceres was the Roman goddess of agriculture). Only a portion of the 50-kilometer-wide crater is shown, but there’s a number of interesting features lurking there.

The most obvious is the small crater right on the rim. It’s younger than Azacca; it overlays the rim, so the impact that formed it must have happened after Azacca was already there. It’s fresher looking, with a sharp rim, though it has smaller craters inside, which implies it’s not exactly young. It’s been around long enough to collect some later impacts of its own.

The bright streaks along the young crater’s rim caught my eye. Once a crater is made, material along the walls can slide down into it, revealing material that was once under the surface. In this case, those brighter streaks are tantalizing. Are we seeing the same sort of bright material that has captured the imagination of so many people since Dawn first approached Ceres back in January of 2015?

The most likely culprit for these bright features is salt. Maybe magnesium sulfate, a common mineral. We know Ceres has a lot of water ice in it, which may have been a subsurface ocean, a mantle of water, early in its history. Salts would have dissolved in it, sticking around even today, long after the undersurface water froze. If so, some sort of process may still be bringing it to the surface to create the bright features we see now.

Look around that crater. See all the bright spots? Here’s a closer view:

Zoom in on the photo above.


Each pixel in the original (1,024 x 1,024) image is about 35 meters on the surface, and many of those spots are 2–10 pixels across, so 70 to 350 meters in width. At least some look like small impact craters. It’s likely there’s ice just under the surface, excavated when small asteroids impact Ceres.

Azacca crater from an earlier image by Dawn. The shots above are centered just outside this image to the lower left.


Interestingly, I found an image of Azacca itself that also shows small white spots in it. I’d expect a large impact would vaporize the ice underneath the crater, yet there are those spots. Is ice from deeper within Ceres coming up through cracks/vents in the crust? There are much larger cracks in the floor of Azacca, possibly due to pressure underneath the crater pushing the floor up (though cracks in the surface have many different sources). Hmmmm.

As my friend Emily Lakdawalla wrote on her blog at the Planetary Society, the key to understanding the surface of Ceres is to understand what lies beneath. There are plenty of clues! With Dawn continuing to map this weird little world in high resolution, the evidence will continue to come in. I hope planetary scientists can make sense of the place. I do love a mystery, but I also love it when it’s solved. There are always more to take its place.

May 18 2016 10:59 AM

A Fantastic Optical Illusion: Just Another Brick in the Wall?

I love optical illusions, especially ones that really twist your brain around. I saw one recently that really had me going for a minute. And it’s not so much the illusion itself that really gets me, but my own brain’s reaction to it.

Click through for the photo. I saw it on a Facebook post from this week, though it’s been around since at least 2014*. It shows a brick wall, seen at a shallow angle, with somewhat large gaps between the bricks. The bricks are red, and it appears that there’s a small, gray rock stuck in between them just above center.

So what’s the illusion? I couldn’t see it at all, even after a good 30 seconds of staring at it. I was starting to suspect there was no illusion, and it’s a gag to fool people, when I read the comments and realized what I was missing.


If you still haven’t seen it, then what follows will spoil it for you. If you don’t want to know then don’t read any further until you’ve figured out the illusion!

May 18 2016 8:45 AM

Watch the Expansion of Debris Hurled Into Space by a Supernova

When you look at the image above, you may be reminded of a cell undergoing mitosis. Certainly, even if you knew it was an astronomical object, you’d be excused if you missed the idea that it’s actually one of the most catastrophic events in the Universe: a supernova.

The violence of a supernova is almost too huge to overstate. When a star explodes (an entire star! Exploding!), the energies involved crush our human perspective into dust. There are two general types of supernovae; one where the core of a massive star collapses, generates ridiculous amounts of energy, and the outer layers explode outward. The other — the kind we are concerned with here — is when a white dwarf (the dead, dense core of normal star) steals matter from a nearby companion, compresses it, and eventually explodes. In both cases, a vast amount of material, as much as an octillion tons of vaporized star-matter, is hurled outward at a significant fraction of the speed of light. This debris covers millions of kilometers in seconds, billions in hours, detonated by a blast that’s equivalent to the entire lifetime’s supply of energy from a star ignited all at once*.

We have observed literally thousands of these events, but, even for the closest, the fantastic speeds of their motions are dwarfed by their distance from us, seemingly frozen in time when you see their images.

Only, that is, if you aren’t patient. In a single image that motion is invisible, but wait a few years, and even the chilling remoteness of a galactic supernova cannot erase the motion of its debris.

And we do have the sharp eyes and glacial endurance of telescopes. In the case of the image above, the Chandra X-ray Observatory (together with radio observations from the Very Large Array in New Mexico) observed a supernova remnant over the course of several years, and when those images are put together in an animation, the expansion of the vast cloud of matter is visible. Behold!

Let that animation repeat a few times; the motion is most apparent in the outer blue ring, the glow from electrons heated to 10 million degrees Celsius by the exploded star’s shock wave. The debris itself is turbulent, bubbling away from the center, and its motion too can be seen over the decade and a half of observations.

As the animation plays, let this thought run through your brain: These observations indicate that in some places in the cloud, the debris is expanding at a numbing 5,000 kilometers per second. In the time it takes you read this paragraph, the gas will have traveled comfortably farther than the diameter of the Earth.

The star that gave up its life for these observations lies between 6,000 and 9,000 light-years from us—60,000 to 90,000 trillion kilometers—and when its light reached Earth in 1572, it was bright enough to outshine every other star in the sky, and even be visible during broad daylight. Astronomer Tycho Brahe was captivated by it, documenting his detailed observations made before telescopes were commonly used to peer into the sky. Had he been able to see its motion, he may have guessed what it was.

To me, this is thrilling. Astronomical objects are so distant and so vast that change in them seems impossible; it feels as if they will appear now as they always have, and always will. But the Universe changes at its own pace, and that evolution is perceivable by humans due to our own curiosity and sense of exploration. Despite its appearance over the puny duration of a human life span, the cosmos is neither eternal nor static. But we only notice if we’re paying attention.

P.S. This type of animation has also been done for the famous Crab Nebula, showing the debris expansion over time as well. It can even be used to determine when the star actually exploded!

*Correction, May 19, 2016: I originally described only a core collapse supernova, but this particular event was from a Type Ia, where a white dwarf explodes. My thanks to Peter Edmonds for pointing this out to me!

May 17 2016 11:45 AM

Sunrise on a Crater Rim

Every now and again, a photograph from a spacecraft stops me dead in my tracks. The shot above is one such image, taken by the wonderful Lunar Reconnaissance Orbiter.

It shows sunrise on the western part of the rim of Jackson Crater, on the far side of the Moon. Jackson is a relatively young crater about 70 km across, with a well-defined rim that extends around it like a single, long rampart bent into a battered circle.

Because the rim rises up from the terrain around it, it’s the first to be lit by the rays of the rising Sun. The Moon spins once every 27 days or so, so sunrise takes 27 times longer than it does on Earth. Here on Earth the Sun takes about two minutes to clear the horizon, so on the Moon it takes roughly an hour.*

What a view that must be! And what magnificent scenery it illuminates. On the Moon, with no atmosphere, there’s no reddish-pink hue to the sky. It’s black all the time, even during the day. When the Sun rises, it must be like a light switch being thrown. Still, the low angle will illuminate the level ground less than something angled up, tilted such that it’s flatter to the incoming rays. So the inside wall of the rim is lit well, the lunar terrain outside the rim still appears somewhat dim, and the inside of the crater is cloaked in inky blackness.

Jackson crater
Jackson crater in all its glory, also taken by LRO, this time in a nadir view.

NASA/Arizona State University/Lunar Reconnaissance Orbiter

The combination of stark lighting, soft lighting, and no lighting at all is entrancing. The moon is always a beautiful object to see, but it’s the shadows that add to the poetry of the composition. There’s mystery and intrigue in the shadows’ edges.

Another reason this image is so striking is that most LRO shots are “nadir angle,” looking straight down at the surface below the spacecraft. This one was taken at an oblique angle, the better to see contours and shadows (a zoomable map of Jackson using LRO nadir images shows just how different it looks in full sunlight and peering straight down at it). Between its unusual angle and the striking lighting, this image has quickly become one of my favorites from a mission that has provided so many stunning photographs of our cosmic companion.

*Ignoring atmospheric effects (on Earth) and latitude, which can actually change the length of sunset significantly. There’s no air on the Moon, but latitude effects can make the sunrise last for many hours or more near the poles.

May 17 2016 8:45 AM

March … I mean April 2016 Is the Sixth … I Mean Seventh Temperature Record-Breaking Month in a Row

N.B. If this article sounds familiar, it should. This has been happening so frequently I just copied the post for March and updated it.

October. November. December. January. February. March. And now April.

For the sixth seventh month in a row, we’ve had a month that has broken the global high temperature record. And not just broken it, but shattered it, blasting through it like the previous record wasn’t even there.

According to NASA’s Goddard Institute for Space Studies, March April 2016 was the hottest March April on record, going back 136 years. It was a staggering 1.28°C 1.11°C above average across the planet.* The previous March April record, from 2010, was 0.92° 0.87° above average. This year took a huge jump over that.

Welcome to the new normal, and our new world.

As you can see from the map above, much of this incredible heat spike is located in the extreme northern latitudes. That is not good; it’s this region that’s most fragile to heating. Temperatures soaring to 7° or more above normal means more ice melting, a longer melting season, loss of thinner ice, loss of longer-term ice, and most alarmingly the dumping of billions of tons of fresh water into the saltier ocean which can and will disrupt the Earth’s ability to move that heat around.

What’s going on? El Niño might be the obvious culprit, but in fact it’s only contributing a small amount of overall warming to the globe, probably around 0.1° C or so. That’s not nearly enough to account for this. It’s almost certain that even without El Niño we’d be experiencing record heat.

Most likely there is a confluence of events going on to produce this huge spike in temperature—latent heat in the Pacific waters, wind patterns distributing it, and more.

JMA temperatures
The Japanese Meteorological Agency measured similar temperatures as GISS (though it uses a different baseline for the average). Note the trend. See a "pause"? I don't.

Japanese Meteorological Agency

And underlying it all, stoking the fire, is us. Humans. Climate scientists—experts who have devoted their lives to studying and understanding how this all works—agree to an extraordinary degree that humans are responsible for the heating of our planet.

That’s why we’re seeing so many records lately; El Niño might produce a spike, but that spike is sitting on top of an upward trend, the physical manifestation of human induced global warming, driven mostly by our dumping 40 billion tons of carbon dioxide into the air every year.

Until our politicians recognize that this is a threat, and a very serious one, things are unlikely to change much. And the way I see it, the only way to get our politicians to recognize that is to change the politicians we have in office.

That’s a new world we need, and one I sincerely hope we make happen.

*GISS uses the temperatures from 1951–1980 to calculate the average. The Japanese Meteorological Agency uses 1981–2010, which gives different anomaly numbers, but the trend remains the same. Realistically, the range GISS uses is better; by 1981 global warming was already causing average temperatures to rise.

May 16 2016 9:00 AM

Astronomers Take the Measure of a Monster Black Hole

Seventy million light-years from Earth lies the somewhat odd galaxy NGC 1332. It falls somewhere in between the two main galaxy types of elliptical and spiral; it’s disk shaped but lacks obvious spiral arms and is quite elongated.

Like all big galaxies, though, it has a black hole in its very center. And not just any black hole, but a supermassive black hole. Current astronomical thinking is that these monsters form at the same time as the galaxy, and affect each other’s growth. Gas pours down to the center from the growing galaxy, feeding the black hole, and the black hole also emits a ferocious wind that can curtail the birth of stars in the galaxy.

When we look at a galaxy now, billions of years later, we see correlations between the mass of the black hole and the behavior of the galaxy. Because of that, knowing the mass of the black hole is important in understanding how galaxies are born, age, and evolve.

But how do you measure the mass of a black hole?

Isaac Newton helps us here. Objects near the black hole orbit it, and the speed at which they move (together with their distance from it) reveals the strength of the gravity of the black hole. That in turn—as Newton pointed out 400 years ago—depends on the mass doing the pulling.

It’s not that simple, of course! But it can be done, and has been done. A camera I worked on for Hubble, called STIS, was designed in part to be able to make these kinds of measurements.

For NGC 1332, various methods have been used, including measuring the velocities of stars near the center of the galaxy (and therefore close to the black hole) and looking at hot gas surrounding the galaxy. These methods have some issues, though, and can have large uncertainties.

A new telescope has come online recently, though, and has something to say about the matter. ALMA, the Atacama Large Millimeter/submillimeter Array, is a collection of large and very sensitive telescopes that detect light well outside the energy our eyes can see—between infrared and radio waves. Very cold gas and dust emit light in this range, and that’s where ALMA comes into the game.

NGC 1332
NGC 1332 (center) has been observed by Hubble (upper left), which showed the dust disk, and ALMA (upper right), which measured the Dopler shift across the disk.

A. Barth (UC Irvine), ALMA (NRAO/ESO/NAOJ); NASA/ESA Hubble; Carnegie-Irvine Galaxy Survey

Many black holes have huge, swirling disks of dust around them. These can be several hundred light years across, the whole thing moving around the supermassive black hole at high speed. Even though they’re big, from 70 million light-years away they look small and hard to see. ALMA, though, has terrific vision, able to resolve the disk down to just a dozen or so light-years from the central black hole.

That’s important. More than about 75 light-years out from the black hole, the gravity of the stars in the central region of the galaxy start to dominate; an estimated 10 billion stars exist within the central 750 light-years. So the closer you are to the black hole, the less an effect the stars have over the hole.

Measuring the disk rotation speed depends on measuring the Doppler effect: The part of the disk rotating around the black hole and heading toward us gets its light blueshifted (the wavelength gets compressed) while the side heading away from us is redshifted (the wavelengths get longer). ALMA can measure these shifts all along the disk, thereby measuring its velocity at different distances from the black hole.

By carefully modeling the gravitational effects of stars and the black hole and applying them to their observations, astronomers using ALMA have determined that the black hole has a mass of—I hope you’re sitting down—660 million times the mass of the Sun.

That’s a lot of hole.

As supermassive black holes go, that’s pretty supermassive-y. Quite a few have been found that are even bigger, but 660 million solar masses is pretty big. The Milky Way’s central black hole has a mass of only (!) about 4 million times the mass of the Sun, for comparison. So the one in NGC 1332 is a lot heftier than ours.

The good news is that this mass jibes with what’s been found for that galaxy using the other, independent methods. That gives us confidence the answer is correct. And the uncertainty in the ALMA measurements is pretty good, only about ±10 percent, better than most other measurements.

And it means we have yet another tool in our kit to measure the masses of these monsters. To put this in context, the ALMA observations aren’t a groundbreaking discovery, but they’re something just as important: a new way to probe distant cosmic objects. ALMA can perform similar observations on other galaxies, building up a census of black hole masses, which can be combined with all our other knowledge to help us better understand the lives of galaxies.

Galaxies are in many ways the building blocks of the Universe, and we happen to live in one, so I’m all for understanding them better. Everything we learn in this way is a piece of the puzzle and adds to the picture we build of the Universe.

I’m all for that, too.

May 15 2016 9:15 AM

Kinked Vortices

Wow! What a great example of von Kármán vortices!

This image, taken by Landsat 8 on May 3, 2016, shows a layer of stratocumulus clouds over the southern Indian Ocean. Poking above the layer is Mawson peak, a stratovolcano (lots of stratos in this shot) on Heard Island, one of a chain of volcanic islands near Antarctica.

The wind is blowing to the east near the island, which creates a wiggling tail of air downstream from the island as it flows around. As that tail “flaps”, the vortices are spawned, which then flow along with the wind. As I’ve written before:

Imagine you have a cylinder (a pencil, or a bucket, or a concrete pylon) that you place in flowing water. It’s an obstacle, and the water will flow around it.
However, near the cylinder’s surface the water slows, piling up a bit. The water farther from the cylinder is moving faster. This causes eddies (vortices) to form, curls in the water. This kind of motion is a bit unstable, and can cause a slight force, pushing the water perpendicular to the direction of flow. But the water all around the flow pushes back, causing a sort of oscillation, like a pendulum swinging. The result is a series of vortices forming and flowing downstream, one on each side of the obstruction, alternating in pattern.
An animation, in this case, is worth way more than a thousand words:
See how the fluid wiggles like a tadpole tail downstream? Eventually those vortices dissipate, losing coherence due to turbulence and drag. This process from start to finish is called “vortex shedding”, which just sounds intrinsically cool.

I love stuff like this, but what makes this even more fun is that in the Landsat 8 image, you can see the winds take an abrupt left turn, suddenly blowing north. That’s not easy to see in the clouds themselves, but it’s pretty obvious when you look at the chain of vortices, which make a sudden change in direction.

I found this picture (via @NASAEarth) on NASA’s terrific Earth Observatory Image of the Day site, one of my favorite places on the ‘net. They also mention that you can use the NASA WorldView page to zoom in and out of this shot, putting in in the greater context of flows around the southern continent. Amazing.

If you’re a US citizen, your tax dollars have already paid for all this, so go play. And if you’re not American, please allow us to let you use this for free. If I may speak for NASA, it’s honestly our pleasure to share our wonderful planet with you.

May 14 2016 10:48 AM

JWST Preps for Its Cameras

On the occasion of the recent revealing of the James Webb Space Telescope’s completed golden mirror array, I wrote a post describing the mirror(s) and how they got their golden atomically layered sheen.

Apropos of that, a couple of pretty nifty videos were recently released. Right now, JWST is in the big “clean room” at Goddard Space Flight Center, a huge warehouselike room that is kept almost entirely free of dust and other particulates that might muck up the optical works. There are a couple of webcams installed there (called “Webb cams,” because of course), and they were online when the entire mirror assembly was moved from the horizontal to vertical position. The result is pretty cool, especially when you consider just how big this assembly is: Remember, it’s 6.5 meters across!

I think my favorite part is at the 30-second mark when all the engineers in the bunny suits pose for a snapshot in front of it.

Here it is from another angle. The color is a bit distorted since it’s through a window, but the gold mirrors are still really something.

The reason the mirror was moved into this position is for the next very, very big step in the assembly: Installing the detectors behind the array. As I wrote before, the telescope is set up so that the big primary array collects the light from astronomical sources, reflects it up to a smaller secondary mirror, which in turn reflects that light down through a hole in the primary down into the instruments behind it. Those instruments include cameras and spectroscopes that will capture and dissect the light from distant galaxies, exploding stars, planets around other stars, Kuiper Belt objects in our own solar system, and much, much more.

Launch is planned for 2018, so there’s still plenty of time for assembly. I’m glad to see, after so many years, this whole thing finally coming together.