Bad Astronomy
The entire universe in blog form

July 23 2016 9:00 AM

Rosetta’s Final Resting Place Has Been Chosen

On Sept. 30 at approximately 10:30 UTC (06:30 EDT), the Rosetta mission will come to an end.

After many days of slowly approaching the comet 67P/Churyumov-Gerasimenko—sending images and data back to Earth the whole way—it will settle down onto the surface of the bizarre little worldlet, what the European Space Agency is calling a “controlled impact.” And at that moment, the spacecraft is expected to stop transmitting.


It’ll have done what it came to do: observe a comet up close, investigate the environment around it, and send a lander down to the surface of a comet for the first time in human history.

That’s quite a docket. And it performed these tasks amazingly.

Sure, the situation with the Philae lander could’ve gone a lot better. But it did send back a passel of data and a handful of amazing images, and even in failure it succeeded in teaching us more about the surface of a comet.

The final resting place of the Rosetta spacecraft itself has been chosen as well: Ma’at, an area that has some “active regions” sending out plumes of gas. It’s located on the smaller of the comet’s two lobes (the head of the rubber ducky, about halfway from the neck up to the top). It’s good choice; if active regions are still doing their thing, we’ll get some truly amazing close-ups of cometary outgassing, the phenomenon that creates the fuzzy head and long, long tail of a comet.

The ESA hasn’t released too many details just yet, but they expect to have more soon. I’ll let you know when I hear.

Follow Rosetta on Twitter for current info, too.

July 22 2016 9:00 AM

EPIC Earth: A Year of Days From Space

NASA has released a pretty amazing video: It consists of more than 3,000 images of Earth taken by the Earth Polychromatic Imaging Camera (EPIC) on the DSCOVR spacecraft.

DSCOVR is in a special orbit, 1.5 million kilometers closer to the Sun than Earth, that keeps it more or less between the Earth and Sun. It faces us, so it always sees the daylit side of Earth, and takes an image every two hours, watching the Earth rotate.


The video shows the Earth over the course of an entire year, and it’s mesmerizing. I suggest you listen to the narration while you watch, done by EPIC lead scientist Jay Herman.

I love the bit about the solar eclipse (I wrote about that when it happened). Sadly, the video ends just before the Moon photobombed the Earth.

There’s one thing not mentioned in the time lapse that I think is really important. Take a look at these two frames from the video:

Earth over the seasons
The view of DSCOVR in August (left) and December (right). Note the change in the position of Australia (arrowed) and Antarctica.

NASA's Goddard Space Flight Center/Kayvon Sharghi

The one on the left is from August 2015, and the one on the right from December 2015. See the difference? I put arrows pointing to Australia, and you can see that in December Australia is up “higher.” Note too you can see Antarctica clearly in December, but barely at all in August.

What you’re seeing is literally a graphic demonstration of Earth’s seasons due to its tilt!

If you watch the video again, you’ll see this. It starts in late July, during the Northern Hemisphere summer. At that time, the north pole is tipped toward the Sun (and therefore toward DSCOVR). You can see Greenland go by, and other northern features.

But over the course of weeks and months, the North Pole tips away from the Sun and the South Pole tips toward it. Antarctica becomes visible. Then near the end of the video the North Pole comes into view again.

Earth orbital motion
The Earth's axis stays fixed in space as it orbits the Sun.

Wikipedia user Tfr000

Mind you, the poles of the Earth aren’t really tipping at all; the axis of the Earth is pretty well fixed in space, and always points in the same direction. But over the course of the year the Earth goes around the Sun, and in the northern summer the pole is aimed “over” the Sun, dipped toward it, and six months later the North Pole is tipped away from the Sun. From DSCOVR’s (and the Sun’s) point of view, it looks like the Earth’s axis is moving, but it’s a matter of perspective.

I suspect this video, combined with a good lesson plan, would work really well in the classroom to show how seasons work. If a student represents the Sun and another student, holding a globe, pretends to be the Earth in orbit, they could physically see how this works, too. A lot of people don’t really understand that it’s the Earth’s tilt that causes the seasons—I’ve explained it many times in talks, and it’s fun to see the look on someone’s face when they really figure it out.

The beauty of this, too, is that this is one of the purposes of the DSCOVR mission: to help people better understand the Earth and our place in the cosmos. The fact that we are on a tilted, spinning, revolving planet affects our lives every single day. If more people understood that, I wonder how that too would affect our lives every day?

July 21 2016 9:15 AM

These Are the Antiheroes We Don’t Deserve

So you’re anti-reality and anti-human-driven climate change, but you can’t find any way to get your kids to listen to you about it? I have just what you need: antiheroes for the age of anti-science.

Presenting Climate Inaction Figures! Seven of the most oil-fueled deniers of science, ready to take up arms and fight against the experts, bad mouth good data, and confuse the public with verbal legerdemain!


Each comes with his or her own super-powered weapon against reality. There’s Mitch McConnell with his Coal Gauntlet, Ted Cruz and his Anti-Science Shield, Sarah Palin and her Drill Sword, and my personal favorite, James Inhofe and his Spiked Snowball:

James Inhofe
James Inhofe's logic is a little slushy.

Climate Inaction Figures

I wonder if he’d use that on the floor of the Senate.

There’s also Donald Trump, Chris Christie, and my other favorite, the two-headed Koch brothers (superpower: money. Lots and lots of money).

I love this idea so much. They even have a commercial:

Sadly, you can’t buy them. Unless you’re a fossil fuel company!

These figures are brought to you by admen Cabot Norton and Arturo Aranda, who partnered with the Years Project—the group that made the documentary Years of Living Dangerously—to create these figures.

The purpose is to raise awareness about the GOP head-in-the-sand syndrome currently scuttling any attempt to do anything about global warming. But it’s more than that: It’s an attempt to get people to understand that there is something we can do. They started the website the Climate Solution to promote the idea of putting a price on carbon, getting companies that pollute the air with carbon dioxide to pay for that pollution, and creating an incentive to reduce emissions.

As former U.S. Labor Secretary Robert Reich explains in a short video, this is the same idea that was behind reducing acid rain due to pollution; companies were forced to pay for that pollution and in a few years the problem was greatly reduced. Fossil fuel companies complain about a “carbon tax” now as they did for the acid rain tax then, but in the end it worked out pretty well. A carbon tax will force these companies to look into more efficient renewable energy production, as well they should.

It’s not that easy, of course, but the problem right now is really the Climate Inaction Team. They won’t even allow it to be discussed, and if we can’t get our politicians to at least talk about it, we can be sure it’ll never happen.

So remember that come November. While the world gets ever-hotter, and the U.S. bakes under a massive heat wave, it’s way past time that the folks who get burned are the ones denying it’s even happening. Vote ’em out of office.

You can follow the Climate Inaction Figures on Facebook, Twitter, Instagram, and Tumblr.

July 20 2016 11:30 AM

March … I Mean April … I Mean May … I Mean June 2016 Is the 6th … I Mean 7th… I Mean 8th … I Mean 9th 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 April May and updated it.

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


For the sixth seventh eighth ninth month in a row, we’ve had a month that has broken the global high temperature record.

According to NASA’s Goddard Institute for Space Studies, March April May June 2016 was the hottest March April May June on record, going back 136 years. It was a staggering 1.28°C 1.11°C 0.93°C 0.79°C above average across the planet.* The previous March April May June record, from 2010 2014 2015, was 0.92° 0.87° 0.86° 0.78° above average. The good news, such as it is, is that unlike previous months, June 2016 didn’t shatter the previous record; it just edged it out in a statistical photo finish. But don’t let that distract you from the important issue: The Earth is way above average in temperature, and overall that temperature is increasing all the time.

Welcome to the new normal, and our new world.

New for July 2016: NASA has created a short video describing its efforts to measure global warming, specifically pointing out that the first six months of 2016 have all been the hottest months on record of their kind:

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.

JAXA June temperature anomalies
The Japanese Meteorological Agency measured similar temperatures as GISS (though it uses a different baseline for the average), and has June 2016 in a virtual tie for hottest June on record with 2015. Note the trend. See a "pause"? I don't.

Japanese Meteorological Society

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.

You may have noticed that the actual temperature anomaly for each month over March through June appears to be dropping; 1.28 to 1.11 to 0.93 to 0.79. That may be due to El Niño weakening, but it’s hard to know over such a short time period. Even if the trend continues, I’d bet 2016 will be the hottest year on record.

July 20 2016 9:00 AM

The GOP Fiddles While America Burns

You want to know the very definition of irony? While the Republican National Convention is going on in Ohio—loaded to the hilt with people who deny the reality of global warming—the country itself is baking under a heat wave that is likely amplified by global warming.

The National Oceanic and Atmospheric Administration just released this model temperature map of the United States:

heat dome
A map of the temperatures across the U.S. on July 18, using sophisticated computer models.



That is a model of the air temperatures in the U.S. at 5 p.m. ET on July 18, showing what’s colloquially called a “heat dome” over about two-thirds of the country. It’s a high-pressure system that squats over an area and can lead to high temperatures. High-pressure systems have sinking air, and when the air drops down, it compresses and heats up. This is causing elevated temperatures from the Southwest to the East Coast, and elevated humidity in much of that area as well.

Worse, the system is moving only slowly … which is very likely to be due to global warming. Usually, such weather patterns don’t hang out very long. But the planet is warming, and this has consequences. Warming affects the Arctic more than lower latitudes, and the strength of the jet stream depends in part on the difference in temperatures at lower latitudes to those in the Arctic. With the North Pole warming, the jet stream weakens, and “blocking patterns” can result, where weather systems move more slowly or not at all for some length of time.

While it’s difficult to pin down any specific event to global warming, overall the effects of warming will make patterns like this more common, and we are seeing more of them.

And at the very same time as this stubborn heat wave with temperatures 5–10°C higher than normal, the Republicans in Cleveland deny that any of it is happening. Donald Trump called global warming a hoax. His vice presidential pick, Mike Pence, also denies it’s real. In a recent interview, Pence said:

I don't know that [global warming] is a resolved issue in science today ... just a few years ago we were talking about global warming. We haven't seen a lot of warming lately. I remember back in the 70's we were talking about the coming ice age.

Those are very typical and very wrong climate change denier talking points. Despite Pence’s claims, we have indeed seen a lot of warming lately, and that bit about a future ice age is just baloney. But this load of fertilizer isn’t too surprising coming from a guy who wrote that smoking cigarettes isn’t so bad for your health.

I’ll note that some Republicans do think the Earth is warming, but very few of them are attending the convention. That doesn’t surprise me; if they actually have a grip on reality, they would want to put as much distance between themselves and the train wreck in Cleveland as they possibly can.

But they should remember that it’s the GOP that created Trump, and in November we should all remember the GOP candidates who deny reality.

Tip o’ the gavel to Gizmodo.

July 19 2016 9:00 AM

Hubble Takes a Long Look Into the Heart of the Crab

7,500 years ago, a massive star exploded.

It had lived a short life, comparatively, running through its nuclear fuel of hydrogen, helium, carbon, neon, oxygen, silicon; each element fusing faster in turn in a sprint to the finish.

Silicon fuses to iron. When that began, everything for the star ended. Iron built up in the core, and several processes conspired to cause the core’s demise. It was already incredibly dense, but fierce and inexorable quantum mechanical laws took hold, squeezing it further. It collapsed down further, becoming a ball of tightly squeezed neutrons just a few kilometers across.

When it did, it released a flash of energy so colossal it defies our puny human brains. To wit: When the core collapsed, the outer layers of the star started to fall in as well. Moving at high speed, this material was a tsunami with a mass of several octillion tons crashing down… yet the flash of energy from the core was so huge it was able to halt the infall, turn it around, and have enough power left over to fling that same material — several times the mass of our own Sun — outward at a significant fraction of the speed of light.

That is the immensity of a supernova. The star had finished, but a new phase had begun.

July 18 2016 12:00 PM

Throwing Shade on a Comet

On Valentine’s Day last year—Feb. 14, 2015—the Rosetta space probe passed an astonishing six kilometers above the surface of the comet 67P/Churyumov-Gerasimenko. Mind you, the comet is only about four km end to end, so this was a very, very close shave.

The images it took at the time are amazing, but not for the obvious reason. Cooler to me was that the flyby was done in such a way that the Sun, spacecraft, and comet were in a perfect line.


So what? Well, that means the spacecraft could see its own shadow on the comet’s surface! I wrote about this event at the time; what’s new is that now all the high-resolution images taken during that pass are online… and that the folks at the European Space Agency put the shadow pass images together into this very cool animation:

Rosetta’s shadow moves from right to left along the bottom of the images. To give you a sense of scale, the shadow is about 20 x 50 meters across! The resolution of the full-scale images is about 11 centimeters per pixel. Wow.

This trajectory was chosen on purpose to measure just how the surface reflects light. With the Sun directly behind Rosetta (called “zero phase angle”) shadows disappear, and there’s a surge in light reflected back. Different surface materials and different surface textures affect that surge, so this is a way to observe that.

The pass took about three minutes, during which time the spacecraft took a dozen shots of ½ a second exposure each.

The high-res images from that pass that are online are fun to look at; here’s one I grabbed nearly at random:

comet surface
The surface of the comet in very high res; objects smaller than a half-meter in size can be seen.


“Nearly at random” just means I scrolled around until I found something neat. This shows a couple of boulders and assorted smaller rocks sitting in a grainy but smooth surface, probably from fine-grain material that’s flowed down from higher elevations into a pit. On the comet, some pits are where ice sublimates, turning directly into a gas, creating the cloud of material surrounding the comet itself, and which get blown back by the solar wind and pressure from sunlight to form the comet’s tail.

Note the parts of the surface that look slumped. That may be due to this very thing; the support under the material goes away as the ice sublimates, so you get a partial collapse. I’m guessing, but I’d bet that’s what this is. There are faint sweeping features around the rocks that look like regions where this happened before, and are being filled in by more material. There might even be some subtle wind action going on here as gas escapes; such things have been seen before on the comet.

The mission received an extension last year, and the end is planned for September 2016, when Rosetta will be gently guided down to the surface. Once down it’s not expected to function any more, but I hope we get images as it descends. What will the comet look like not from six km, but three? One? A hundred meters?

It wouldn’t be true to say I’m looking forward to the end of this wonderful and spectacular mission. But what an end it will be.

July 18 2016 9:00 AM

Greenland Is Still Melting Away

A new paper just published by scientists in Geophysical Research Letters presents results of their investigation into the ice sheet covering Greenland. They found that over the four-year period from Jan. 1, 2011 to Dec. 31, 2014 Greenland lost over a trillion tons of ice.

Let me repeat that: More than a trillion tons of ice melted away from Greenland.


These results, using the Cryosat-2 satellite, actually matches pretty well with other measurements made using different methods; for example, using data from the GRACE satellites scientists found Greenland loses ice at a rate of about 287 billion tons per year.

These numbers are staggering. To give you a sense of scale: A trillion tons of ice would make a cube over 10 kilometers (six miles) on a side. That’s taller than Mt. Everest, and would have about three times that mountain’s volume. And that much ice disappeared from Greenland in just four years.

But no, really, it didn’t disappear. It had to go somewhere. And where it went was into the ocean, adding water to it. Distributed over the Earth, that means sea level rose about 2.5 mm over those four years. That rate of sea level rise from Greenland ice melting was twice as rapid as the average rate from 1992-2011. I’ll note that 2012 was unusual across the Arctic, with far more warming than usual, less snow cover than usual, huge sea ice losses, and higher loss of Greenland land ice as well. But even with that, the trend is, dare I say, alarming.

Mind you, that’s just from Greenland, and doesn’t include melting from Antarctica, which is occurring at about half the rate of Greenland (the Arctic is more prone to warming and melting that the Antarctic). Every year, these two land masses lose about 400 billion tons of ice combined, draining it into the ocean, causing sea level rise.

This fresh, cold water also disrupts critical current flow that transports heat from the Equator to the poles, and cold water back again. This may also affect the jet stream, which in turn gets weaker, allowing frigid Arctic air down to lower latitudes in the winter. Common in this situation is the formation of stalled “blocking patterns” in summer that prevent storm systems from moving easily, bringing droughts in some areas and floods in others. In 2013, a torrential downpour in my home of Boulder occurred because of one of these blocking patterns, and the results were horrendous—some places got nearly half a meter of rainfall in a few days. That same year, Alaska had a terrible heat wave, again due to these blocking patterns.

The evidence that global warming is behind all this is so overwhelming is difficult to overstate. But I’ll note that the likely Republican nominee for President calls global warming a hoax, and his Vice Presidential pick called it a myth. I’ll also note that the Democratic likely nominee not only acknowledges the reality of global warming, but also has a plan in place to deal with it. I could wish for something more aggressive from her, but given the infuriatingly sorry state of the GOP attitudes about science and reality, this is a case of taking what you can get.

July 17 2016 9:30 AM

A Moment of Clarity in the Milky Way

There are times in life—perhaps too few, but they exist—when you can try to grasp the Universe, and a piece of understanding settles into your mind like the glow of a billion stars.

This photograph, titled “Moment of Clarity”, by Michael Shainblum is the visualization of that moment. A master of Milky Way and night sky photography, Shainblum took this in Davenport, California during a calm, clear night in 2015. It’s a composite of several exposures (to help reduce the grainy-looking digital noise when capturing faint objects) that reveals the Milky Way, and Shainblum himself silhouetted in the foreground.


Remember, that fuzzy glow you see in the photo is the combined light of many billions of stars, reduced to a milky swath by their terrible distance. Yet for all that space we are a part of the galaxy, created by elements forged and seeded by supernovae within it, living on a planet circling one of the trillion or so stars held by the gravity of all the others.

See? It’s a moment of clarity indeed.

July 16 2016 9:30 AM

Time-Lapse: Vorticity

Mike Olbinksi is a wedding photographer based out of Arizona. He’s also a storm chaser, and creates jaw-dropping time-lapse animations of weather systems that have to be seen to be believed (like “Monsoon II”, and one of a Texas supercell spinning up that looks like it came from a big budget science fiction movie).

His latest is called “Vorticity”, and, well, just watch.


No, wait: Make it full screen and high resolution, turn up your volume, and then just watch:

Holy. Yikes.

As you watch, here’s a checklist to watch out for:

I like how Olbinski timed his footage to the music; it adds a drama to the scenes and forces you to pay attention to certain motions in the clouds.

It’s summer here in Colorado right now, and I’ve been seeing all sorts of amazing cloud structures. I have a few pictures I need to post here too… because the science behind them is amazing, but also because of their intense and sometimes almost alien beauty.

I think that sometimes science is like a paintbrush and supplies, and the sky is a canvas. Science obeys rules, and creates clouds in certain ways over and again, but there’s so much wiggle room inside those boundaries that no two works of nebular art are ever the same. And they’re always masterpieces.