Bad Astronomy Blog

Asteroid Collisions Create a Forbidden Crystal

4 hours 55 min ago

Crystals are pretty. They’re also pretty interesting. They’re found in nature in stunning variety, including all kinds of bizarre shapes. I find a lot of these shapes pleasing aesthetically due to their symmetry. Some are box-shaped, some hexagonal… but they’re all fascinating.

Crystals get this symmetry because of the way atoms interact. They’re like puzzle pieces, connecting only in certain ways. For example, carbon atoms can bond to each other to form sheets that are a single atom thick, but contain zillions of carbon atoms interconnected as hexagons. We call this graphene. But they can also connect to form tetrahedrons, four-faced triangular pyramids. The property of that crystal is very different, so we give it a different name: diamond.

Over the years crystallographers have found that there are four kinds of symmetries natural crystals can have: 2-fold, 3-fold, 4-fold, and 6-fold. These are all based on taking a shape and rotating it 360°. For example, take an equilateral triangle. If you spin it 360° it looks the same. But it also looks the same if you spin it 120° and 240°. So after spinning it all the way around, you get the same pattern three times: a 3-fold symmetry.

A regular hexagon has six sides, and looks the same after you spin it 60°, 120°, 180°, 240°, 300°, and finally 360°. So it has 6-fold symmetry.

Now, you could theoretically have a 5-fold symmetry, for an object that goes through multiples of 72° rotations (after five of those you’re back to 360°). But that’s never found in nature. The other symmetries are very strong, and crystals find themselves displaying those instead.

… until recently. In the 1980s scientists were able to create a 5-fold crystal in the lab, which they called a quasicrystal. It’s tough to do, but it can be done. Still, the big question remained: Can that be found in nature?

The answer we now know is: Yes! Scientists found two such crystals in nature, and they came from the same source: a meteorite that fell in far eastern Russia called the Khatyrka meteorite.

Meteorites generally come from asteroids. Collisions break them up into smaller pieces, and sometimes these fall to Earth. Khatyrka has an unusual composition, and when examined microscopically indeed shows signs that it had undergone collisions while it was still part of its parent asteroid body. The scientists wondered if they could replicate this. They created a series of disks made of the same minerals found in the meteorite and stacked them like coins, making something like a hockey puck. They then used a large gas gun to blast it with a projectile moving at about one kilometer per second, which is a typical (or perhaps somewhat slower) collision speed for asteroids in space.

When they examined the result, they found a quasicrystal with 5-fold symmetry, which is now named icosahedrite. The chemical formula for it is Al63Cu24Fe13: 63 atoms of aluminum, 24 of copper, and 13 of iron in each molecule. No wonder it’s so hard to find it in nature!

It’s not entirely clear in detail how it formed, though sudden compression, heating, and then cooling play a role. On Earth those conditions are very rare, but they’re more common in asteroids. The weird composition of the meteorite plays some part too, having the right combination of minerals to start with such that in the end the quasicrystal is created.

At this you may be wondering, so what? I have a few whats for you. One is that nature is more clever than we are. These crystals were once thought impossible, but here they are. They’re rare, but not impossible. Just very unlikely and need very special conditions to form.

Second, this gives scientists more insight into the literal structure of nature. Perhaps quasicrystals will never have a practical application, but even if they don’t they still help us understand how the world is put together.

And third, this hints at new branches in the science of crystallography. What other crystals exist, what other strange compounds? What uses will these have? Maybe none, at least not in our ability to exploit them for technological advances, say (the way silicon was used to make computer chips as an example). But again, the more we understand the rules governing the Universe, the better we understand it, and that is a goal unto itself.

And hey, if we can figure out how to make transporters or warp drives or light sabers, then all the better. But in the meantime, just gaining knowledge is pretty cool, too.

P.S. I’ve been meaning to write about this topic for a little while, but tonight I’m giving a talk about science outreach to members of the American Crystallographic Association at their meeting in Denver, so I thought the time was right.

Categories: Astronomy Headlines

More Evidence That Dinosaurs Suffered a One-Two Extinction Punch

Mon, 07/25/2016 - 06:00

What killed the dinosaurs?

That was a mystery for decades; when I was a kid, there were tons of ideas but precious little evidence for any of them, making them little more than speculation. In the late 1970s and early ’80s, though, the hypothesis was put forward that a giant asteroid or comet impact did the deed, and over the years evidence mounted.

The impact idea gained wide acceptance, but some details remained stubbornly difficult to explain with a single catastrophic event. Another idea that started gaining traction was that a series of huge and sustained volcanic eruptions occurred for a couple of hundred thousand years before the impact. These were no ordinary eruptions; they formed the Deccan Traps, a soul-crushingly huge region in India consisting of igneous rock layers more than two kilometers deep and covering an area of 500,000 square kilometers.

Half a million square kilometers. Yeah: huge.

This long-lasting eruption did ecological damage across the planet, weakening life and killing species. The clock was ticking on the dinosaurs and so many other species. When the impact came, their time was up.

There’s pretty good evidence that it took both catastrophes to do in the (non-avian) dinosaurs and 75 percent of species on Earth, but a new study provides more support: Scientists found two warming pulses in Earth’s ocean temperatures corresponding to the times of both the volcanic eruptions and the giant impact. This suggests that large-scale global climate change effects were behind the mass extinction.

The scientists examined the shells of bivalves that lived around Seymour Island, near the tip of the peninsula sticking out from Antarctica. This is a good location to do this; the island dates back to before the time of the impact (called the Cretaceous-Paleogene boundary, or K-Pg boundary—C was already used for something else, so geologists went with K) and fossils from that time are abundant on the island. The deposits layered there provide a continuous sampling from before to after the boundary with little or no jumps in time, so the record is relatively clean.

They looked at bivalves because the critters absorb minerals from the water to make their shells, and the ratios of the amounts of some minerals in the water is temperature dependent. By carefully measuring the minerals in the shells (specifically, the ratio of oxygen-18 to oxygen-16), the scientists can then use them as a proxy for temperature.

What they found was a huge ~8° C (± 3°) leap in water temperature starting around 66.25 million years ago (roughly 150,000 years before the K-Pg boundary), which is when the Deccan Traps eruption started. The water started cooling again, but then there was another sharp rise of a little over a degree right at the K-Pg boundary, corresponding to the impact. That’s on average; some of the bivalve samples showed much larger spikes in temperature.

I’ll admit, the data look a little rough to me. The second pulse has pretty big uncertainty bars, so it’s hard to tell exactly how big it was. The first pulse looks quite real, though, and does support the idea that the Deccan Traps contributed to geologically sudden and biologically deadly worldwide warming.

Interestingly, there was a long, slow warming and cooling period for a couple of million years before all this. While it was a large rise (about 8°) it happened over a long period of time, so the ecological impact wasn’t as bad. A smaller rise can do far more damage if it happens quickly, a point many climate change deniers ignore.

We use the dinosaurs as a metaphor; something slow, plodding, not terribly intelligent, and in imminent danger of going extinct. This new study shows that to still be apt; they were ill-prepared for both sudden climate change and a giant asteroid impact.

Humans are smarter than that. We have a space program, which is useful in both aspects; it can help prevent an impact, and our Earth-observing satellites are telling us very plainly that the climate of our planet is rapidly changing.

We’re not dinosaurs … if we choose not to be.

Categories: Astronomy Headlines

Time-Lapse: The Skies Over Dry Tortugas

Sun, 07/24/2016 - 06:00

How have I never heard of Dry Tortugas National Park until now? It’s a little over 100 km west of Key West, Florida, in the Gulf of Mexico. It’s pretty remote, accessible only by boat or seaplane, and has an interesting history.

It’s the location of Fort Jefferson, a huge brick fortress that was constructed over a period of 30 years in the 19th century but never completed. It was built to protect the busy waters at the entrance to the Gulf, and was also a prison —Samuel Mudd was sent there, convicted for conspiring with John Wilkes Booth in the assassination of Lincoln.

It was a miserable place to be incarcerated, with terrible conditions. When I read that I was astounded; that’s bizarre given how gorgeous the waters are there: crystal clear, with coral and abundant fish. Ironically, it’s a tourist destination now known for its beauty.

And it’s even more bizarre when you think about how beautiful the skies are there. With no land except a few small sandy islands all the way out to the horizon, the skies there are fiercely dark at night, and the stars shine with brilliant intensity.

I learned all this when photographer Harun Mehmedinović sent me a note about his newest time-lapse video, “Tortugas Rock”, which is a stunning display of just how spectacular this site is:

Whoa. Mehmedinović employed a variety of effects to enhance the scenes, including stacking frames to create star trails that show the motion of the stars in the sky, reflecting the Earth’s rotation on its axis. Because it’s so far south, from this location the Milky Way gets higher overhead than it does from most of the US and really dominates the video when it’s visible.

I also really like the music. It's called "Escape Velocity", and was written by Terry Devine-King. You can find more of his work online.

Mehmedinović  made this as part of the Skyglow Project, an effort he’s undertaking with fellow photographer Gavin Heffernan to visit remote locations and document the skies there. Their goal is to underscore the issue of light pollution and the damage it causes. I support this effort.

Watching this video and reading about the park, I have to add this place to my ever-growing list of spots on Earth I wish to see. It’s no coincidence that many of these are remote, difficult to access, and not well known. All of these are ingredients that add up to a dark sky and spectacular viewing at night. I sometimes wonder if there are enough nights to visit them all.

I’ve written about some of Mehmedinović’s work before; check these out:

Categories: Astronomy Headlines

Rosetta’s Final Resting Place Has Been Chosen

Sat, 07/23/2016 - 06:00

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.

Categories: Astronomy Headlines

EPIC Earth: A Year of Days from Space

Fri, 07/22/2016 - 06:00

NASA has released a pretty amazing video: It consists of over 3000 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 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:

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.

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), 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?

Categories: Astronomy Headlines

These Are the Antiheroes We Don’t Deserve

Thu, 07/21/2016 - 06:15

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:

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.

Categories: Astronomy Headlines

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

Wed, 07/20/2016 - 08:30

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 their 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.

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.

Categories: Astronomy Headlines

The GOP Fiddles While America Burns

Wed, 07/20/2016 - 06:00

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:

That is a model of the air temperatures in the US at 5:00 p.m. EDT on July 18, 2016, 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.

See more of Slate’s election coverage.

Categories: Astronomy Headlines

Hubble Takes a Long Look Into the Heart of the Crab

Tue, 07/19/2016 - 06:00

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.

The light from this flash traveled outwards in all directions, and, about 6,500 light years later, that spherical wave of light passed by the Earth. A bright star erupted in the constellation of Taurus on July 4, 1054, then faded over the course of many weeks. Humans didn’t have the scientific understanding then to know what they had seen, but 704 years later a comet hunter named Charles Messier saw a faint fuzzy object in his telescope. It looked like a comet, but clearly wasn’t. Frustrated, he made a note of its position, and even started a catalog of such objects that he might accidentally confuse with comets.

Thus we now call this object M1, for the first object in Messier’s iconic catalog of interesting objects in the sky. But most people know it as the Crab Nebula.

Even now, more than a millennium later, we see the gas in the explosion expanding. We also see the collapsed core of the progenitor star, still glowing hot from the fires that forged it. We call it a neutron star, and moreover it’s a pulsar, appearing to blink on and off as it spins rapidly, two hot spots marking its magnetic poles swinging into and out of our view. And again, to emphasize the boggling nature of this, remember that that is an object with more than mass than our own Sun, but it’s spinning 30 times per second.

And it’s still a force to reckon with. It blows a fierce wind, energizing electrons around it into a flow moving outward at relativistic (extremely high) speeds. This gas glows blue, as can be seen in the newly released Hubble image above. It fills the volume around the pulsar (the upper-right star in the bright pair near the middle of the image). The gas forms ripples that expand outward into the ribbons and filaments of the gas from the star itself that exploded long ago (seen as mostly red).

The Hubble image shows this expansion in a sneaky way. Observations from 2003, 2005, and 2013 were combined to create this image. Over that time the wind from the pulsar expanded, moving far more rapidly than the gas from the explosion. So while the fine tendrils around the edges of the image appear motionless, the Crab wind made slightly larger ripples in each subsequent observation. Displayed in different colors, this creates a rainbow effect, revealing that incredible expansion.

I’ve seen the Crab a few times through my own telescope, and it never look like much more than an elongated blob. Larger telescopes reveal the finer structure, and Hubble shows us just how fine it is; those streamers look like the shredded remains of an explosion, leaving no doubt of the cause of this magnificent structure. At one point years back, astronomers would commonly say that their field of study could be divided fairly evenly into two groups: The Crab Nebula, and everything else.

That’s changed over the years; we now know of many more kinds of objects than we did back then. Exoplanets, black holes, staggering varieties of stars and galaxies, worlds in our solar system, and more. But the Crab is one of the nearest and best studied supernova explosions, and one of the most beautiful to boot. It will always be a centerpiece of astronomical study, and astronomical artistry.

Categories: Astronomy Headlines

Throwing Shade on a Comet

Mon, 07/18/2016 - 09:00

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:

“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.

Categories: Astronomy Headlines

Greenland Is Still Melting Away

Mon, 07/18/2016 - 06:00

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.

Categories: Astronomy Headlines

A Moment of Clarity in the Milky Way

Sun, 07/17/2016 - 06:30

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.

Categories: Astronomy Headlines

Time-Lapse: Vorticity

Sat, 07/16/2016 - 06:30

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.

Categories: Astronomy Headlines

A Beauty That Hides a Beast

Fri, 07/15/2016 - 06:30

I’ve seen (and posted) so many pictures of spiral galaxies that it takes a lot to really get me to say, “Wow”.

WOW.

This image stopped me in my tracks. It’s NGC 6814, a large spiral galaxy about 75 million light years from Earth. It’s a hair smaller than our Milky Way, about 90,000 or so light years in diameter, and it’s a real beauty.

This image was taken using Hubble Space Telescope, and it’s an unusual combination of colors. What’s displayed as blue is actually yellowish light at 555 nanometers wavelength; what looks green is actually 814 nm (very red, even near-infrared light), and what’s shown as red is actually 1.6 micron light, well out into the infrared. I find that interesting; it’s not what your eyes would see, but it does look very much like a natural-color photo of a spiral (I’ll add this image was processed by Judy Schmidt, whose work I’ve featured here on the blog many times).

At first glance it seems pretty normal, if spectacular. A central bright nucleus, an elliptical hub of stars around it, and then those glorious spiral arms, looking cloudy blue from countless massive luminous stars. You can see a tinge of reddish-pink which is usually from gas clouds… but in this case that’s infrared light, so it’s probably from dust. And speaking of dust — grains of rocky, silicate material and long carbon-based molecules that are nothing so much as soot — you can see dark bands running through the arms where thick clouds of dust block the visible light from stars.

And on top of all this is a smattering of stars inside our own galaxy; we live in the Milky Way, and have to peer out of it to see more distant galaxies. It’s like looking through a slightly dirty window to a scene outside.

Still, there’s more going on here than you might guess. In the heart of this galaxy is a feeding monster.

We know all big galaxies have huge black holes in their centers; they form at the same time as the galaxy and grow along with it. The one at the core of NGC 6814 isn’t all that big as they go, about 10 million times the mass of the Sun, or a little over twice the mass of the supermassive black hole in the Milky Way’s center.

Our black hole is quiescent, though, inactive. Not so the beast in NGC 6814. It’s actively feeding, matter swirling around it at high speed. This disk is the last stop for any material falling down into the black hole; it piles up there and heats up hugely due mostly to friction. This makes the core of the galaxy unusually bright, and if you look you can see there is a bright knot of light at the very center. We call galaxies like this Seyfert galaxies.

But there’s more. Elements heated in a gas cloud emit light at very specific colors, and these act like fingerprints or DNA samples, allowing us to determine what chemicals are in the gas. Oxygen, hydrogen, and carbon are commonly seen, along with many others. As the gas moves around the black hole, its light gets blue shifted as it heads toward us and red shifted when it heads away. The amount of shifting tells us how fast the gas is moving, and can also help determine the mass of the black hole.

In this case, we see gas pretty far out from the black hole (the light isn’t shifted a lot) as well as gas very close in, which is moving much more rapidly, tens of thousands of kilometers per second. This affords astronomers an excellent view of what’s happening all around the black hole.

We knew all this before this magnificent Hubble image was taken, though. These observations were actually made to measure the light output from very bright stars that are known to change their brightness, called Cepheid variables. They pulse, and the time it takes them to pulse is related to their total energy output. By timing these variations, and knowing how bright the stars appear, their actual energy output can be used to gauge their distance. That tells us how far away the galaxy is!

So this is much, much more than just a (jaw-droppingly brain-staggeringly) pretty picture. This is a key to cosmos itself, a way to determine the size and scale of the Universe we live in.

In astronomy, there’s never any such thing as just a pretty picture.

Categories: Astronomy Headlines

Pluto + 1: A Year After New Horizons Made It a World

Thu, 07/14/2016 - 05:30

One year ago today, on July 14, 2015, the New Horizons spacecraft shot past Pluto and its system of weird moons, making space history (and the history of the mission itself is great reading). It was the first time a probe had been sent to an ice world specifically to study it in detail, and —depending on your personal viewpoint— Pluto was the first dwarf planet ever seen up close, or the last planet seen up close, or the first Kuiper Belt object seen up close.

Whatever. Pluto is what it is, and what it is is amazing, and beautiful, and most of all surprising.

Before New Horizons, we did know some things about Pluto. It has one large moon, named Charon, and four smaller moons. Pluto is very shiny and reflective, probably due to nitrogen snow and ice, while Charon is much darker. Crude maps made using Hubble observations showed that Pluto had darker and brighter regions, but Pluto is just too small and far away even for the world’s biggest telescopes to reveal surface features. So while we knew quite a bit about it, what we didn’t have was details.

That changed 366 days ago.

New Horizons launched from Earth on Jan. 26, 2006, and took more than nine years to reach Pluto, even with a gravity assist from Jupiter (which shaved two years off the mission). That ought to give you an idea of just how far away Pluto is; it took nearly a decade to get there even traveling faster than 40,000 kilometers hour.

But on July 14, 2015 it finally flew past Pluto and its odd set of moons. And when it did, Pluto went from a blurry dot to a world unto itself, with all that implies.

One of the most important features scientists were anticipating was cratering. The solar system is filled with objects big and small, and over time that means impacts. These leave behind craters, and by counting craters on the surface you can get a decent estimate of the age of the surface. Even as far out as Pluto there are enough objects that cratering was expected.

When the first images came back from New Horizons, what we saw was… huge swaths of Pluto with almost no cratering. That wasn’t just surprising, it was shocking. Most scientists expected Pluto to look a bit like the Moon, with craters densely packed on the surface. Instead, they got places with few or even no craters at all.

A big area devoid of craters means it’s young, relatively speaking. Scientists estimate those regions on Pluto may only be a hundred million years old or less. That’s youthful, geologically speaking!

That in turn means that parts of Pluto have been resurfaced, like an old road having its potholes filled in with fresh material. But what process could possibly do that on cold, frozen Pluto?

It turns out the answer to that may be even more surprising than the lack of craters itself. It’s not as frozen as we were led to believe.

On approach to Pluto, the most obvious feature was first thought to be shaped vaguely like a whale (and was even nicknamed that), but resolved itself to be a huge heart-shaped plain. The whole region is called Tombaugh Regio (after Clyde Tombaugh, who first discovered Pluto), and the “left hand” side Sputnik Planum. Although every part of Pluto is interesting, Sputnik Planum turned out to be amazing.

Close up shots revealed it to be very flat, reflective, and covered in segmented plates that look almost like cells. The best guess is that what we’re seeing is a frozen nitrogen shell covering a more fluid interior. Some source of heat deep inside Pluto is causing convection under the surface, with warm fluid rising and cooler material sinking. The segmented plates are the tops of these cells of convection, with warm stuff pushing up in the center of the plates and the cooler material sinking around the edges. The material isn’t liquid as we usually think of it, but more like toothpaste in consistency.

What’s the heat source? Good question. It’s possible that a small amount of radioactive material exists deep inside Pluto, and as those elements decay they warm their environment. In fact, some scientists investigated this possibility due to several very large cracks seen in Pluto’s crust. What they found is nothing short of staggering: Pluto may have an ocean of liquid water under its surface!

The cracks would have been generated as the water closer to the surface froze and expanded, pushing up on the surface. This idea is preliminary, but terribly exciting. If true, it shows that liquid water can exist on (or under) worlds when just a short time ago we would’ve thought it impossible (or extremely unlikely).

Another strange sight on Pluto’s Sputnik Planum are huge fields of what look like pits in the surface, from tens to hundreds of meters in size. These may be sublimation pits; if a small pock or dip exists on the surface sunlight can warm it, turning the nitrogen from a solid directly into a gas (that’s called sublimation), making the dip grow. They appear to form in lines, and sometimes sweeping curves. It may be they formed that way due to stress patterns in the surface, or perhaps they align as the surface moves slowly, responding to the convection from underneath. Either way: Weird. That seems to be the operational word for Pluto.

Pluto doesn’t have plate tectonics like Earth does, so mountain building would be unexpected… and yet, there are mountains on the tiny world. And they’re not little; some tower 3,500 meters (11,000 feet) over the surface! These are likely to made of water ice; at Pluto’s surface temperature (-230° C!) water ice is as hard as rock here on Earth. They’re also coated with a layer of methane ice, which may have fallen as snow just like water does on mountains on Earth.

The thing is, it’s not at all clear what forces pushed these mountains up. They’re far higher than anyone would have guessed, so something with a lot of oomph forced them up. Perhaps it’s connected with the heat source in the core, or the potential liquid water ocean under the surface. Scientists are still scratching their heads over this.

New Horizons screamed past Pluto at high speed, but even after closest encounter it wasn’t done. Once past Pluto it turned around, taking images of it “from behind”, so to speak, with Pluto backlit by the Sun. The idea was to see if Pluto’s ethereally thin atmosphere could be seen.

The image above makes it quite clear it could! But surprises lurked there as well. The atmosphere isn’t just a big puffy shell around Pluto, but layered, with dozens of distinct layers. These are composed of haze, complex organic (carbon-based) molecules built up as ultraviolet light from the distant Sun breaks down simple molecules like methane, which then reorganize themselves into molecules like acetylene and ethylene.

The major component of the atmosphere, though, is nitrogen, just like Earth’s. Also, just like here at home, these molecules scatter sunlight, giving Pluto’s atmosphere a distinctly blue hue! If you were standing on Pluto (and adequately protected) and looked up you’d almost certainly see a blue tint to the sky, especially near sunrise and sunset, when you’re looking through more of the atmosphere toward the Sun.

Pluto has about the most alien landscape in the solar system, yet there is a part of it that is quite Earth-like. How about that?

We knew very little about the large moon Charon before the flyby, other than it was about half the diameter of Pluto, and orbits once every six days (actually, they orbit each other, doing the barycenter dance). When New Horizons flew by, what we got was… Frankenstein’s moon.

Seriously, it looks like someone grabbed a moon, ripped it into big chunks, and then slapped them back together again. Look at it! The southern hemisphere is relatively smooth, though pocked with craters, but the northern half looks, well, wounded. It’s not clear what causes the dichotomy, but it’s likely that Charon and the other smaller moons formed when Pluto was hit by a large object, splashing material into space which coalesced to form the moons. Perhaps the topography is a remnant of that event.

The north polar region of Charon is very dark, and has been nicknamed Mordor Macula (a macula is a spot or blotch, and Mordor is a place you don’t simply walk into). It’s quite red, and no one is sure what it is. It might be an impact basin, or it might be dark due to Pluto’s atmosphere leaking complex carbon molecules into space which then collect there.

Charon also sports a deep canyon called Argo Rupes. It may have the tallest cliffs in the solar system, some nine kilometers top to bottom. If you jumped off the edge, it would take four minutes to fall to the bottom!

Unlike so many other NASA missions, New Horizons didn’t go into orbit around Pluto. The outer solar system is so far away that the probe burned up nearly all its fuel to get there as rapidly as possible, and it would’ve taken a huge amount more to slow the craft down enough to enter orbit. So this was a flyby, and a very rapid one at that. What we got is what we got. Nearly all the data from the flyby have been sent back to Earth now, and will keep scientists busy for decades.

But what’s next? New Horizons sails on, and there’s still more solar system out there. Just a couple of weeks ago NASA gave the go-ahead for a mission extension, granting permission for the spacecraft to visit another object, called 2014 MU69, a Kuiper Belt object that’s probably 40 or so kilometers across and about 6.5 billion km from the Earth. On Jan. 1, 2019, New Horizons will give it a very close shave, passing just 12,500 km from its surface (that’s less than the diameter of the Earth!), getting our first close-up views of what’s thought to be a pristine remnant left over from the formation of the solar system itself.

What will we see?

Who knows? That’s the beauty of this. If we knew what we’d find, it wouldn’t be exploration. But if we take what we learned at Pluto, then the lesson of New Horizons is clear: Expect surprises.

Ironic, isn’t it? But that’s precisely what we get every time we explore a strange, new world. And there are many, many such worlds awaiting us in just our own back yard. New Horizons may have been the first, but you can bet it won’t be the last.

Categories: Astronomy Headlines

What Do You Do With a Problem Like Space Debris?

Wed, 07/13/2016 - 08:58

Space junk is becoming a real problem.

It’s a serious issue. There’s a common misconception that things in space are just kindof floating out there, moving slowly—and given videos of spacewalks and what we see in movies, that’s understandable.

But it’s wrong. There are thousands of satellites orbiting the Earth, moving at incredibly high speeds. Note the plural, “speeds”; not everything is traveling at the same speed or in the same direction. Two objects moving at 25,000 kph in different orbits can have a relative speed of several kilometers per second. At that velocity, a fleck of paint can have a catastrophic impact.

If two entire satellites collide, the problem is hugely worse; they create a shower of debris that expands and can hit more satellites, creating a cascade of debris. This was the basis of the movie “Gravity”, you may recall. That flick grossly exaggerated the problem for dramatic effect, but the overall idea was based on reality. In fact, in 2009 just such a situation occurred when a defunct Russian communication satellite slammed into Motorola Iridium satellite; the energy of the impact utterly destroyed the two and created two clouds of debris moving in different directions.

Space debris is a very real threat. What can be done about it? NASA and the Department of Defense have been cooperating on this for a long time, but the European Space Agency is looking into taking the next step: a satellite called e.Deorbit. It’s in the proposal stage, awaiting ESA approval to actually get started. But if approved, the hope is that it will be tag, snag, and bag large pieces of orbital debris, then perform a de-orbit burn to drop them both into Earth’s atmosphere where they will burn up.

It’s ambitious, I’ll say that, but the basic idea makes sense. It will use advanced imaging techniques to identify debris, approach it carefully, securely capture the debris (either by deploying a net or harpoon that will hook it, or a grapple that will grab it), then drop down to a fiery disposal during re-entry.

ESA put together a nice video explaining the concept:

I think this is a good step in reducing the problem. Bear in mind it’s one step; the problem of small (centimeter-sized) debris is still a huge one. There are quite a few ideas floating around (so to speak) on how to mitigate that, including using lasers to heat up the debris and change their orbit, dropping them down into the atmosphere to burn up, and a Japanese idea to use a space tether to create an electromagnetic field that alters the orbits of debris. It would also help to create satellites that shed less debris in the first place, and ESA is looking into that as well.

I’m all for that. If we go about business as usual, the space around Earth will get clogged with material, making routine access to space more dangerous. Something must be done, and it’s nice to see government agencies taking it seriously.

Categories: Astronomy Headlines

Juno’s First Light

Wed, 07/13/2016 - 06:00

This is pretty neat: The image above is the first one taken of Jupiter and its moons by the Juno spacecraft after achieving orbit last week*. This was taken on July 10, 2016, when the Juno was a little over four million kilometers from the giant planet.

In the shot you can see Jupiter in a way we can’t from Earth: half full. Jupiter is five times farther away from the Sun than Earth is, so when we look at it from our planet we’re always seeing it more or less full. Even when we’re off to one side in our own orbit, seeing Jupiter from an angle, that angle is so small that Jupiter always looks essentially full to us.

But once you get far from the Sun, the geometry changes. Juno approached Jupiter “from the side”, catching up to it in its orbit around the Sun. It then entered into a polar orbit around the planet, on a path that will take it over the poles of Jupiter. The first two orbits are very long and elliptical, and then it’ll fire its engine again (in October) to drop it down closer.

After it burned its engine for an astonishing 35 minutes Juno was on almost exactly the orbit planned. It dipped low over Jupiter, then started moving away. The image above was snapped on the outbound leg of that first orbit, less than a week into the 53.5-day journey around the planet.

Seeing Jupiter half full is pretty amazing to a seasoned astronomer like me. I’ve observed the planet hundreds of times through binoculars and telescopes, and this view of it is nothing less than jaw-dropping.

You can see some details in the clouds too, like two of the main dark belts (the reddish-brown bands) and lighter colored zones. The Great Red Spot shows itself too, that ridiculously huge storm that’s been around for centuries, and could easily swallow a few Earth’s without a hiccup.

Three of Jupiter’s four large moons are in the shot as well (Callisto, which orbits pretty far out, isn’t seen). Juno’s mission is focused on the planet, not the moons, so we won’t see any close-ups of them, though we’ll get more scenes like this in the future.

But just you wait. Juno’s orbit will take it as far as 2.7 million km from Jupiter at apojove† (the point in its orbit farthest from the planet), then it will dive to a stunning 4,000 km above the cloud tops, screaming past the planet at nearly 60 kilometers per second, roughly 200,000 kilometers per hour! At that speed, it could get from the Earth to the Moon in two hours.

The point being, when Juno is close to Jupiter, it’s close. The images we’ll get from it will be staggering. They won’t come for a while yet, so be patient. I know they’ll be worth the wait.

* The very first image taken by a new telescope or detector is called “first light”, which I think is quite poetic and lovely. While technically this isn’t the first taken by Juno (we got a nice animation taken while on approach), it’s the first taken from orbit, so that counts.

Correction, July 13, 2016: I originally wrote "perijove" here (which is the closet point in its orbit to Jupiter) rather than "apojove". My apologies for any confusion.

Categories: Astronomy Headlines

Moon Photobombs Earth

Tue, 07/12/2016 - 08:45

NASA’s Deep Space Climate Observatory, or DSCOVR, is a satellite that orbits the Sun about 1.5 million km from the Earth. That’s a (meta)stable orbit that keeps it between the Sun and Earth, so that when it looks at our planet, it sees its fully illuminated face.

A couple of times per year the dances of the Earth, Moon, and DSCOVR line up so that it sees the Moon pass directly in front of the Earth. And when it does, it’s actually pretty magical:

Yes, this is a real animation, and not a simulation. It’s composed of images taken by DSCOVR on July 5, 2016 (a similar transit was seen in 2015). There’s a lot to see here! You may have noticed the Moon looks much darker than Earth. That’s real. The Moon on average reflects about 15 or so percent of the sunlight that hits it; the Earth is much shinier, reflecting closer to 40 percent.

The Moon looks funny, doesn’t it? Where are all the usual features you see in photos? They’re on the other side. The Moon spins once every orbit, so it always keeps the same face toward Earth. DSCOVR orbits the Sun farther away than the Moon orbits the Earth, so when the Moon passes between the satellite and Earth it sees what we would call the Moon’s far side. And because the Sun is behind DSCOVR, the Moon and Earth are both full. Or very nearly; it’s slightly off line, so you can see a bit of the unilluminated part of the Moon and Earth, both on the right. This means that if you were on Earth looking at he Moon, it would have been up during the day, and very close to its new phase.

Also, just above the Moon’s path, to the right of center on the Earth, you can see the ominous swirling spiral of Typhoon Nepartak. This powerful storm swept over Taiwan and China, killing many people and doing extensive damage. Weather events like this are terrifying and devastating, but from so far away they’re disturbingly beautiful; it’s one of the most persistent and dark ironies of space exploration.

A large part of DSCOVR’s mission is to raise public awareness of our planet, and how important observing it from space is. Sure, it’s pretty cool when the Moon photobombs Earth, but there’s much more going on with these images. I suggest you explore them for yourself, and take a look at our planet… and see that it really is a planet, one of countless many, but for us the most important. For at least a little while longer, it’s the only one we live on.

Categories: Astronomy Headlines

“Clean” Coal? Yeah, Not So Much.

Tue, 07/12/2016 - 06:30

If you thought the upcoming GOP National Convention was going to be anything other than a look into a parallel dimension, then here’s a taste of what to expect. On Monday, July 11, 2016, the Republican National Committee had a hearing to work out the wording for the GOP platform, their list of beliefs and goals supported by the party and its members.

During these hearings, one of the topics was the use of coal. David Barton, a delegate from Texas, had an edit he wanted to make to a sentence in the platform. Watch:

Here’s what he said:

I would insert the adjective “clean” along with coal particularly because [of] the technology we have now. So, “the Democrat [sic] party does not understand that coal is an abundant clean affordable reliable domestic energy resource.”

In a sense, Barton is right: The Democratic Party* doesn’t understand that, because it’s utter baloney. “Clean coal” is a myth, a marketing term. Coal isn’t clean. Not even close.

If you want to be honest, the term should be “cleaner coal”, or more accurately “somewhat less dirty coal”. Coal is one of the major sources of energy production in the US (providing 33 percent of the total, comparable to natural gas). It gets burned, which turns water into steam, which drives turbines, which then generate electricity.

Coal has a lot of other things in it besides carbon, including mercury, sulfur, and more. These pollutants get into the air and cause a lot of problems, including thousands of premature deaths every year. Scrubbing these toxins out of the coal is costly and very difficult, though new power plants do a better job at this than old ones.

But the elephant in the room is that carbon. Burn it and it combines with oxygen to make carbon dioxide, and this of course is a greenhouse gas. Humans put about 40 billion tons of CO2 into the air annually, far more than any natural source on the planet (including volcanoes). Because this is heating the Earth up and changing the climate, it’s important to figure out a way to capture the carbon and somehow store it to prevent it from getting into the air. This is called “carbon capture and sequestration”, or CCS.

The problem? The technology to do this doesn’t exist. Not in any real sense of the word, that is. There have been some pilot projects done, but they’ve managed only to scratch the surface in the vast amount of CO2 released.

Now to be fair, I won’t say CCS is impossible. Perhaps, in a couple of decades, a few tens of billions of dollars invested, and a few technological breakthroughs, it may become a reality.

But right now? No way.

All of this makes it pretty clear that what Barton was peddling in his interjection of the platform committee hearings was pure nonsense. Calling coal “clean” is just this side of a lie, and at best is horribly misleading. Adding that word to the platform is just another fairy tale substituted for science by the GOP.

I’ll note that Barton himself is a fervent climate change denier; he gave testimony at a US Senate hearing in 2007 that is loaded with scientific errors. Even then we knew that much of what he stated in that testimony is flatly wrong. He misstates the role of aerosols in global warming (confusing it with their role in hurting the ozone layer), talks about global cooling, and more. He has a colorful history with reality, too.

I’ll also note that the leader of the platform committee, John Barrasso (R-Wyoming), is also a climate change denier. Because of course.

Once the Republicans finish hammering out their platform and put it online I’ll take a look at it, but you don’t need to be psychic to know what it will say about a lot of the issues. The party’s guiding principle has been the flat denial of reality for quite some time now — Donald Trump is like anti-Nobel Prize they’ve won in that category — and it’s a sure thing that’s all we’ll see from them for a long time to come.

Tip o’ the bitumen to Climate Desk.

* Note Barton’s use of the phrase “Democrat Party”, a term used specifically to make them sound bad. If someone uses it to start a sentence, you can be sure that the next thing they say would be useful as fertilizer.

Categories: Astronomy Headlines

Measles Outbreak in Arizona Likely Fueled by Vaccine Refusals

Mon, 07/11/2016 - 08:40

The largest outbreak of measles this year is occurring right now in Arizona. There have been 22 confirmed cases so far since late May. Up to that point, there were only 19 cases in the entire country in 2016.

The outbreak is attributed to the Eloy Detention Center, a privately run federal immigration detention center. This doesn’t surprise me; measles was eliminated in the U.S. in 2000, but people traveling to the U.S. (including Americans returning from foreign countries) are the biggest source of outbreaks. Disneyland was the epicenter of a measles outbreak in 2015 for just this reason.

The likely carrier in the Arizona situation was a migrant, but the problem was amplified by unvaccinated employees at the facility. The detainees have been cooperative and received vaccinations, but apparently many of the employees have been refusing or haven’t shown proof of vaccination.

It’s not clear why. Perhaps they’re simply anti-vaxxers, unable or unwilling to accept the reality that vaccines are one of the safest medical modalities available; their huge benefits far, far outweigh their very small risk. The vast majority of claims by anti-vaxxers are false. They don’t cause autism. They aren’t loaded with toxins. And on and on.

Remember too that the modern anti-vax movement started due to a discredited doctor who fraudulently connected vaccines with autism, performed unethical tests on children (!!), and had a tremendous conflict of interest. Still, it’s taken hold in various communities, and anti-vaccination tendencies have caused many outbreaks around the world, including in the U.S.

I hope this Arizona outbreak doesn’t get any worse, but measles is highly contagious and the workers who aren’t vaccinated could very easily spread it to the public at large. An infection from measles can result in high fever, but in children it can produce much more devastating complications, including permanent hearing loss, pneumonia, encephalitis, and even death. If you live in Arizona read up on the symptoms and be cautious.

Please talk to your doctor and check to see if you need your vaccination (usually given as an MMR combination with mumps and rubella). The people most at risk are infants too young to be vaccinated, and people with compromised immune systems; for example, those undergoing chemotherapy, or who have auto-immune diseases. A family member of mine has the latter, so for me this is personal. I’m up-to-date with all my shots, and so is everyone in my immediate family. We walk the walk.

Vaccines work. They wiped out smallpox globally, and polio is on its way out as well. Rubella has been eliminated in the Americas, too. Measles was stopped dead in its tracks once in this country. Let’s make it happen again.

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