Bad Astronomy
The entire universe in blog form

Feb. 3 2016 12:13 PM

Science Ranch 2016

Update, Feb. 7, 2016: As of today, Science Ranch 2016 has sold out. However, we do maintain a waiting list in case spots open up. If you want to be on the list, please contact us!

If you love science (and yes, you do), meeting other people who also love science, and being outdoors in a spectacular setting, then do I have something for you.

My wife and I run a company called Science Getaways, where we take fun vacations and make them better by adding SCIENCE. Today we’re announcing our next getaway: Sylvan Dale Guest Ranch in Loveland, Colorado.

Science Ranch 2016, as we’re calling it, will be from Sunday, July 31, to Saturday, Aug. 6. The Sylvan Dale Guest Ranch is located at the foothills of the Rocky Mountains, in a really lovely valley where the Big Thompson River comes out of the mountains. Some of the rocks in the cliff walls visible from the ranch are well over a billion years old! The geography and wildlife of the area are just breathtaking.

bighorn sheep
Bighorn sheep are a common sight in the hills next to the ranch.

Sylvan Dale Guest Ranch

Speaking of which, we’ll have three guest scientists joining us: Dr. Dave Armstrong, an ecologist who co-owns the ranch and knows the area extremely well; Dr. Holly Brunkal, a Colorado geologist and a perennial Getaways favorite (this will be the fourth time she’s joined us); and my old friend Dr. Dan Durda, an expert on asteroids and suborbital spaceflight. All three will give talks, and Dave and Holly will lead us on hikes to see the biology and the geology of the region up close.

And, as usual, I’ll be giving a talk, and I’ll have my solar telescope for viewing activity on the Sun as well as my trusty 20 cm Celestron telescope to take advantage of the dark skies there.

You’ll also have the option to take a day trip up to Rocky Mountain National Park (included in the vacation*), one of my favorite places in the world. The views from up there are truly magnificent.

horseback riding
The ranch sits on a huge chunk of land that goes into the hills, and you can ride horses up there.

Sylvan Dale Guest Ranch

There’s plenty to do at the ranch, too: horseback riding, trap shooting, cookouts, an overnight pack ride, bass fishing, campfires, a heated swimming pool … and an optional river raft ride down the Cache la Poudre River. Or you can simply sit by the Big Thompson River outside your cabin and read a book. We’re very low pressure about activities; do or do not, as you see fit. The lodging rate includes three home-cooked meals per day and all the ranch activities.

This Getaway is also perfect for families; there are activities just for kids, including riding and horse care, and their inquisitive minds will love the hikes and other science activities we’ll be doing.

Sylvan Dale is a second-generation family-owned guest ranch. If you’ve never been to a dude ranch, you’re going to fall in love with this type of vacation. The ranch is very comfortable and homey; it’s not at all like a hotel or resort. It’s a wonderful atmosphere, and we love it. But what makes Science Getaways really special, and what keeps people coming back so frequently, are the folks you’ll spend the week with. Science Ranchers (as we call those who come on our ranch vacations) are some of the friendliest, most fun and interesting people you’ll ever meet. A Science Getaway is not so much like taking a group vacation, it’s more like hanging out with 30 friends in a really cool place.

If this sounds like fun to you, then head over to the Science Getaways page and reserve a spot. We’re keeping attendance lower than usual for this one, and we expect it to sell out. I hope to see lots of BABloggees there!

*Note: Travel to and from the ranch is not included in the price; check the registration page to make sure what is and is not part of the price.

Feb. 3 2016 9:30 AM

Sometimes They Come Back: Giant Gas Cloud on Collision Course With the Milky Way

In 27 million years, you’d better fasten your seat belt: Sometime around then, a gas cloud with enough mass to make 2 million stars like the Sun will come crashing into the Milky Way.

Given the time frame, I’m not too concerned personally over this galactic train wreck. Also, stuff like this happens pretty often in our galaxy, and we’ve made it this far.

Still, it’ll be quite an event, and there’s a funny twist to it: We don’t really know where this cloud came from.

It’s called the Smith Cloud (it was discovered by astronomer Gail Smith in 1963, who was mapping the location of hydrogen gas in the sky), and by all accounts it’s a bruiser: It’s more than 10,000 light-years across; so big that even at its distance of 40,000 light-years (almost halfway across the galaxy!) it appears 30 times wider than the full Moon on the sky.

It’s part of a class of objects called high-velocity clouds; generally pretty big clouds of gas whizzing around outside the body of the Milky Way. Quite a few have been seen, but at 2 million times the mass of the Sun, the Smith Cloud is one of if not the most massive (most are tens of thousands of solar masses). The Milky Way is, overall, a flattish disk, and Smith orbits at a slight (30°) angle to it. Right now it’s about 10,000 light-years below the disk and headed up into it.

trajectory of Smith
The path of the cloud over the past and future.


Where did this thing come from? There are lots of possibilities: It could be a “dark galaxy,” a clump of gas and dark matter that never formed stars. Or it could be a clot of gas left over from the formation of the Milky Way, orbiting far outside the galaxy, which got disturbed and plunged inward. Or it could be a cloud ejected from the Milky Way itself, blasted out into deep space and now finally heading back.

To find out, astronomers were clever. If the gas cloud were primordial—that is, very very old—it should consist of just hydrogen and helium, the lightest elements. Heavier elements have only been around in the Universe since stars created them, so by looking at the cloud’s ingredients we might be able to eliminate a couple of origin stories.

Using an ultraviolet camera on Hubble (called COS, the Cosmic Origins Spectrograph) they looked for the fingerprint of sulfur in the cloud. That element absorbs a very specific wavelength (color) of UV light (you can learn more about how this works in an episode of Crash Course Astronomy). Helpfully, the cloud’s size betrayed it: It’s so big it happens to cover up several very distant galaxies that emit a lot of UV light. Using those galaxies as light bulbs, the astronomers looked to see if there were any anomalous absorption of that wavelength of UV.

… And there was! Careful analysis indicated that the amount of sulfur in the cloud was pretty high. Kilo for kilo, it has about half the sulfur the Sun itself does (we use the Sun as the standard for such things, because in principle its elemental composition is easy to measure). There’s no way it could have that much sulfur and be left over from the early Universe. So boom, right away we know it isn’t some leftover gas cloud that’s been lurking in the Milky Way’s rural areas.

And we also know it’s not a dark galaxy, either: You need stars to make sulfur, and dark galaxies wouldn’t have any stars.

That means it must be local in origin, a cloud somehow ejected from the disk of the galaxy, where heavier elements are abundant.

galactic fountain
An infrared map of the galaxy reveals a blowout: A popped bubble of gas (lower left) that could be the origin of a high-velocity cloud.

ESA/Hi-GAL Consortium

We do know of ways that can happen. In several places along the galactic disk are “fountains,” huge eruptions of material blasting out into near-galactic space. These can be generated by a series of exploding stars, or by the fierce winds blown by thousands of young stars all forming at the same time in galactic gas clouds. The vast outflow of material can burst through the galactic plane like a geyser, ejecting a lot of material upward and outward.

And, like a fountain, sometimes that material comes back. The Smith Cloud must have formed that way. It may have started off smaller, but as it plowed through the material located in our galaxy’s halo, it picked up mass. And now it’s ready to deliver all that stuff back to us.

Like I said, lots of high velocity clouds like this are known. What’s interesting is that if you add them all up, they deliver about one solar mass worth of material every year to the galaxy. That is very roughly the same amount the Milky Way uses up every year making stars! So these clouds are like fuel, keeping star formation in the galaxy going. How about that?

Not that this entire mystery is solved. Smith is moving pretty rapidly through space—about 300 kilometers per second, or a million kilometers per hour—and that’s actually faster than the rotation of the galaxy at its location! Most such clouds are actually moving slower than that, so how Smith got its high velocity still isn’t clear.

So what will happen when it does come back? Well, the disk of the galaxy is lousy with gas. When Smith comes barreling in, it may very well collide with that gas. This will generate vast shock waves and collapse the cloud (think two cars in a head-on collision). If it gets dense enough, star formation could be triggered inside it, with thousands of stars being born all at once.

There are multiple sites of star birth in our galaxy, and some are pretty rigorous. This may be just one among them, though I suspect the velocity at which it’s moving will make this somewhat more violent than normal. Two million solar masses moving at a million kilometers per hour …

The galaxy is a surprisingly violent place. In astronomy, though, violence usually means something interesting. It’s how they form, it’s how they die, and it looks like in this case it’s even how they make sure there’s fuel left to generate more. It’s the ultimate recycling program.

Feb. 2 2016 12:00 PM

Mars From a Height

I post a lot of news and pictures of Mars, and when I do it’s usually something taken by a rover on the surface, or it’s a high-resolution image of a small region taken from orbit.

I love these images, and they give us a sense of the kind of detail going on at the surface of Mars. But it can be easy to forget that Mars is actually a world, a huge place with sweeping vistas.

I was reminded of this when I did my usually daily check-in with my friend Emily Lakdawalla’s blog at the Planetary Society. She posted a handful of simply spectacular images of the red planet that were taken by the European Mars Express mission, and processed by Justin Cowart.

The image above shows the Tharsis Shield of Mars, a tremendous bulge in the side of the planet with four volcanoes popping out of it, including the famous Olympus Mons, the largest mountain/volcano in the solar system. I love the overview we get here, including the blue edge of the planet caused by its thin atmosphere.

Cowart’s Flickr page (and his Twitter stream) is a marvel of astronomical imagery, shots from around the solar system, including Saturn and its moons, the comet 67/P Churyumov-Gerasimenko, and more. It’s well worth your time to take a look. There’s nothing wrong with a reminder of how gorgeous our local neighborhood in the Universe is.

Feb. 2 2016 9:00 AM

“Let’s Make Sure That History Never Forgets the Name … Enterprise

This year marks the 50th anniversary of the most influential science-fiction series of all time: Star Trek. I’m a pretty big fan (Evidence A/B, Evidence 2, ad inifinitum), and I could go on and on about its influence, the characters, the music, and all that. But really, at the center of the show, there is one singular icon: the USS Enterprise.

Oh, that ship. Nothing had ever been seen like that before on TV or in movies — the unusual design and construction, unfettered by the need for gravity or aerodynamics or landing on a planet, yet still sleek and compelling.

For years the original model of the Big E used in the original series (or TOS to those of us in the know) was on display at the Smithsonian’s National Air and Space Museum. But the decades have taken their toll, and the model is currently undergoing reconstruction.

NASM has a great blog, and they just put up a wonderful article talking about the process. If you’re a Trek fan, this is a must-read. The pictures alone are worth it.

Full ahead, warp factor 4.

Phil Plait

As a huge Trek fan myself, I have to tell you about a time I got a piece of the action. Last year, NASM asked me to participate in a fundraiser to help preserve Neil Armstrong’s lunar EVA suit from Apollo 11. I talked with them on the phone about it,and joked that I’d love to be a part of that, but on one condition: I had to be able to see Enterprise myself.

They didn’t hesitate at all. “Of course,” was the reply I got.

“Oh,” I may have replied. I’m not sure, because my memory of that moment is a bit fuzzy. I may have blacked out for a second.

But they were serious. So when the time came … I boldly went.

USS Enterprise
These are the continuing voyages of the starship Enterprise.

Phil Plait

I went to the NASM Udvar-Hazy Center, where the spacesuit was being conserved. We spent the morning shooting some of the scenes for the promo video (including in a huge room with the Space Shuttle Orbiter Discovery hanging on display), which was fun. Then we moved to a part of the center where some of the real work is done: extremely talented professionals working on preserving and conserving priceless artifacts. We walked into the room where we were going to see Armstrong’s suit … and there she was.

Oh, that ship. Look: Seeing Armstrong’s suit up close (literally even being able to smell it) was a profoundly moving experience, and one I will cherish literally as long as I live. It represents the reality of space travel, of what we did when we had the will.

But that in no way diminishes seeing the Enterprise model, which represents our dream of space travel, of what we hope one day we’ll do. Inspiration comes from many directions, and those dreams play an important role in motivating the reality.

"Admiral, what about the rest of the inspection?"

Phil Plait

So standing up close to Enterprise, the actual model used in the original series, was thrilling. Thrilling. The ship that started it all, right there in front of me.

It made me think about watching the show when it was in its first reruns, my older brother commenting to me about what was going on as the scenes unfolded (I was pretty young at the time). I had memories of watching Next Generation in grad school, bookending my career there (the first episode aired my first year, and the last one aired seven years later, just before I got my Ph.D.). I flashed back to standing in line at the theater to watch Wrath of Khan, and eventually meeting and even becoming friends with some of those galactic explorers.

To boldly go.

Phil Plait

Making this encounter even better was meeting Ariel O’Connor, who is a conservator on the model. I wound up chatting with her about all manners of things; she is a font of information about it, with encyclopedic knowledge of its history. More than that, her affection for Enterprise is also readily apparent. Let me assure you, the NCC 1701 is in excellent hands. I’m not sure I’d trust it more if Kirk himself were in charge (after all, he didn’t always bring it home in the best of condition).

Even in its partially disassembled state, it was surreal to stand next to it. For one thing, it’s big: nearly four meters long. The coloring on it is odd, and they’re working on restoring it to its original hues. But even in that room, secured to its support stand, it looked ready to warp away to seek out brave new worlds.

I made a short video showing it; I had to speak softly as the crew was working behind me doing some video of Armstrong’s suit:

At one point, we realized it had to be moved to another spot in the room, or else it would be in our shots of the spacesuit. Several people hovered over it as they wheeled it a few meters over to the corner, and I practically swallowed my heart as they moved it. But these folks really are at the top of their game, and everything went very smoothly.

When we are all done filming, Armstrong’s suit was covered up and wheeled away, and we all headed out the door. As we did we filed right past Enterprise, taking up the corner of the room. I took one last lingering look, knowing how special this day was. It’s not often you get to see some of the greatest and most beautiful icons of space exploration history (both real and imagined) in your lifetime.

It’s not clear when the refit will be done, but at some point the model will be finished, and placed back on display at the museum. And when it does, I must return to this place again.

Live long, and prosper.

Phil Plait

My sincere thanks to the folks at NASM for letting me use these photos and write about this moment … and of course for giving me this chance to see Enterprise.

Feb. 1 2016 9:15 AM

Climate Change Denier Claims (Heh) That 2015 Wasn’t (Ha) the Hottest Year on Record (HAHAHAHA!)

I (and many others) have shown that the loudest voices in the climate change denial noise machine have long since run out of any real credibility. There are numerous ways to reach that conclusion; for example you can look at how their claims have changed over the years (there’s no warming, there’s not much warming, it’s not warming enough to worry about, warming is good for plants, sure it’s warming but it’ll hurt our economy to do anything about it), you can look at their funding sources (tobacco and fossil fuel interests) whose tactics they deploy, or the fact that they rely on long-debunked claims instead of any real evidence.

But despite this, they do go on. And have no doubt: What they say has real-life consequences—life and death consequences, in fact, for millions of people. More. I’ll get back to that in a moment.

As the denial never seems to cease, I think they’re not only short on credibility, they’re also just short on ways to sell their snake oil. Their ideas get weirder and less believable every time they speak.

That’s the only conclusion I can draw when the claims I see now are so ridiculous, so outrageously, blatantly wrong that it’s hard to believe they can make them with a straight face.

I recently read an op-ed that falls firmly into this category, and it was no surprise at all that it came from James Taylor, from the bizarre world of the Heartland Institute. Remember them? They put up billboards comparing climate scientists to mass murderers, and when people were outraged at the obviously despicable claim (and they hemorrhaged donors because of it), they took the billboards down and, in Orwellian fashion, claimed victory.

So yeah, a view of reality twisted into a Möbius strip is just another day for them.

Taylor’s article was printed in Forbes, and right away, just from the headline, you know you’re about to take a trip into WTFery: “2015 Was Not Even Close to Hottest Year on Record.”

Forbes headline
All the news that's cherry-picked to print.


This is one of the wrongiest wrongs to have ever been wronged. Yes, far and away, without question, and where it counts, 2015 was the hottest year on record. Many, many temperature readings confirm that, and it’s not even close; even if you account for El Niño (which tends to make things warmer overall), 2015 blew away the previously hottest year of 2014.

So how can Taylor make this claim? Well, as usual, it’s to cherry-pick a very, very specific set of circumstances: Satellite measurements of a single layer of the atmosphere. As I (and many others) have shown, these satellite measurements are not terribly reliable over the long term, and are nowhere near as accurate as temperatures measured from the ground using thermometers.

Despite this, Taylor states, “By contrast, temperature measurements at the Earth’s surface are less reliable,” which is just flatly wrong. Seriously. It’s just complete fertilizer. If you think I’m being too harsh, then I suggest you read what actual climate scientists have to say about Taylor’s claims, because you’ll see words and phrases like “total fabrication” and “very misleading” and “disingenuous” and “inaccurate” and “wild misrepresentation.” I’m pretty gentle by comparison.

Here’s an analogy for you: Taylor saying satellite measurements show 2015 isn’t the hottest year is like inspecting a horrendous car crash, finding the steering wheel intact, and claiming the accident never happened.

The article is embarrassingly bad, even for an op-ed in Forbes (which has run several such comically wrong articles by Taylor in the past). It’s just so egregiously and obviously and in-your-face wrong, though, that I have to assume it’s aimed only at those who are ideologically predisposed to believe him, in an effort to sow doubt.

hottest year graph
Can you spot the hottest year on this graph? Click for an explanation.

Berkeley Earth

And that’s where the consequences come in. Because some of the people ideologically predisposed to use his claims as fodder are other deniers. And some of them have real power, like, say, Ted Cruz. R-Texas.

As a sitting senator (and hopeful GOP presidential candidate), Cruz has access to the best and most accurate science, yet he chooses to ignore it, or worse, actively squash it.

I am no fan of Cruz's, as you might imagine. He is incredibly disingenuous to the point of outright lying, as has been shown many, many times. Cruz distorts the truth so glibly that it’s impossible to know what he truly believes, so it’s possible he really does think the planet isn’t warming up. Or (as seems far more likely) it may be he’s purposely bending his interpretation of reality to match the ideologies of his audience and his benefactors (as I've wondered before, wouldn't it be interesting if senators had to swear to tell the truth during hearings in which they sit? Hmmm.)

But either way, Cruz is dead wrong about global warming. And he uses the same kind of satellite-based argument Taylor does. Cruz still claims warming has flattened since 1998, which has been shown to be so completely, utterly wrong in every way that his making that claim again speaks to his lack of veracity ... but still, Cruz runs the Senate Subcommittee on Space, Science, and Competitiveness, where he trots these claims out as fact.

While it’s almost trivially easy to show that Taylor and Cruz are wrong, they still forge on ahead with as much inertia as global warming itself. In Taylor’s case he’s aided and abetted by such venues as Forbes (and other deniers can find refuge in such places as the Wall Street Journal and the Daily Mail, where, apparently, facts are optional).

Cruz has his own outlets, of course. And since an overwhelming tsunami of scientific evidence shows they’re both wrong, they have to rely on what is sadly a tried-and-not-true technique: barreling on, steamrolling over anyone who speaks against them, and hoping against hope that their own audience won’t call them on it.

Postscript: Speaking of calling them on it, Monday is the Iowa GOP caucus, so it’s important to note that not a single viable Republican presidential candidate has a good grasp on global warming.* A vote for any of them means at least four more years of doing nothing about what has been called by people who would know a threat to our national security. I agree. If someone denies basic science on an issue this important, they do not deserve the office of president.

*Correction, Feb. 1, 2016: This post originally misstated that Iowa's GOP primary is taking place Monday. It is a caucus.

Jan. 31 2016 9:00 AM

SPECTACULAR Photos of a Rocket Re-Entering Over Hawaii!

Around 2 a.m. local time, astrophotographer Steve Cullen was driving home from visiting the summit of Mauna Kea on the Big Island of Hawaii. He stopped at around 11,000 feet to take some panorama shots of the peak … but what he got was much more.

He noticed an orange light heading up into the sky out of the west. It was moving across the sky at about the speed you’d expect from a satellite, but at that time of night no satellite moving at that rate would be lit by the Sun, so it wouldn’t be visible.

Within seconds, though, it became clear what he was seeing: some sort of human-made space debris re-entering Earth’s atmosphere. How?

Because this. Check. This. OUT.

Jan. 30 2016 9:00 AM

Crash Course Astronomy: Outtakes 5

The final episode of Crash Course Astronomy went up last week, but if you miss it already, we have one final video for you: the fifth outtakes reel, which basically features me trying to pronounce common words as if I have a mouthful of oatmeal.

That bit near the end, where I seem way more upset about messing up thanking people than it calls for? That’s because it took a ridiculous number of takes to get that bit right. I lost count. Maybe 20? More? Mind you, this was literally the very last thing we were recording. Ever. We were wrapping up a long day of being in the studio, I had just finished the content for the final episode, and all I had to do was thank the fantastic folks who put CCA together. And I kept flubbing it. It was really frustrating. Over 46 episodes, that was easily the most failures I had getting the lines out. 

But I did (eventually), and we wrapped the series. So again, thanks to Nicole Sweeney and Nick Jenkins for making me look like a dork. If you want more, Outtakes One, Two, Three, and Four exist as well.

By the way, the entire CCA series is now online. When you’re done binging whatever’s on Netflix, give this one a shot. The whole Universe is waiting for you.

Jan. 29 2016 9:15 AM

By the Light of the Zodiac

Given how much time I’ve spent outside at night looking up, it’s funny to think there are still quite a few phenomena I’ve never seen. One that’s very near the top of my list of “Must See” things is zodiacal light.

This is the glow of dust and particles shed by comets, ones that orbit the Sun on relatively short paths. Over time these objects are influenced by the gravity of Jupiter, so we call them Jupiter-family comets. Made of ice and rock, they shed this material as the Sun warms them. Eventually, this stuff suffuses through the inner solar system, sticking pretty close to the same orbital planes as the planets, forming a flattish disk.

From Earth, we see the material reflecting sunlight back to us, glowing in a band across the sky. The photo above, taken at Mauna Kea by Rogelio Bernal Andreo, is one of the best shots I’ve seen of zodiacal light. It’s very faint, so you need dark skies—which the volcano provides (I think the faint streak across the middle is from a satellite).

Now follow along here: The planets, including the Earth, orbit the Sun on pretty much the same plane (from the side, the solar system’s planets’ orbits look flat). From the Earth, it looks like the Sun moves around us once per year. The path it takes across the sky is the same year after year, and we call this the ecliptic. The planets all move across the sky in that same path, too.

So, like clockwork, the Sun passes into the same constellations at a certain time every year. You know the names of these constellations: Sagittarius, Libra, Scorpius, Aries, Gemini … the constellation of the zodiac, or, if you prefer, the zodiacal constellations.

Since the glow we see from the cometary dust is also in this same plane, it too sticks to the same constellations, and we therefore call it zodiacal light. How cool is that? Cool enough that after a few years spending time in some rock band, a guitarist decided to go back and get his Ph.D. studying it.

Interestingly, the dust we see is not constant. Solar wind, interactions with Jupiter, and other effects would eventually blow it all away. It’s replenished by more comets coming in and renewing it. I found a paper describing this, and the astronomers found that the amount of dust injected into the cloud must be around 100,000 kilograms per second. That’s a stunning 3 billion tons per year!

Mind you, that’s spread out over a lot of volume. Like, trillions of cubic kilometers at least. So it’s pretty thin stuff … but thick enough to be seen, at least from Earth on a dark, Moonless night, and photographed so that we humans can gaze upon it in awe and wonder about the marvelous working of our solar system. That’s a pretty good deal for us, I think.

Jan. 28 2016 12:12 PM

And the David N. Schramm Science Journalism Award for 2016 Goes To …

I am very honored to let y’all know that I have received the David N. Schramm Science Journalism Award for 2016!

The annual award is given by the High Energy Astrophysics Division of the American Astronomical Society, the largest society of professional astronomers in the U.S., and is meant “to recognize and stimulate distinguished writing on high-energy astrophysics. The prize was established to improve the general public’s understanding of this exciting field of research.”

The award’s namesake, David Schramm, was an astrophysicist who studied the Big Bang. Much of his research involved how the lightest elements (hydrogen, helium, and lithium) were created in the first few moments after the birth of the Universe, and how those would affect other properties we see in the cosmos today. I never met him, but I wish I had; he sounds like he was an interesting fellow.

HEAD gave me the award for an article I wrote in Slate last year called, “A Supermassive Black Hole’s Fiery and Furious Wind,” about how the matter piles up and heats up around a black hole, which can blow off a ferocious wind of particles so strong it can sculpt the shape of the entire galaxy around it. Here’s an excerpt:

We also know that every big galaxy we look at has a supermassive black hole in its very center. If that black hole has gas and matter falling into it, the accretion disk can be huge and ridiculously, soul-crushingly bright. The luminosity of such an object can easily outshine the hundreds of billions of stars in the host galaxy, and make the black hole visible clear across the Universe.
This sets up an interesting problem. When you have a monster in the middle like that, how does it affect the rest of the galaxy? A curious fact was discovered many years ago; the mass of the black hole in a galaxy seems to correlate with how the stars in the galaxy orbit. You might think “duh” to that, but hang on. Even though a black hole can have a mass of a billion times the Sun, that’s a teeny tiny fraction of the mass of a galaxy with a few hundred billion stars in it.
Somehow, the black hole is affecting the galaxy around it on a huge scale. How?

If you want the answer, click through. I had a lot of fun writing that article. It covers a big, sweeping topic—why the sizes of gigantic black holes are apparently tied to the large-scale behavior of galaxies, which isn’t at all obvious—and uses new findings to help answer a question that had been bugging astronomers for years.

The field of high-energy astrophysics doesn’t have a hard and fast definition, but it covers objects and events that can generate high-energy light at the top of the electromagnetic spectrum: X-rays and gamma rays. These are among the most violent events in the Universe: exploding stars, colliding galaxies, gamma-ray bursts, black holes gobbling down matter, newly formed neutron stars glowing fiercely hot, and the like. I’ve always had a love for such brain-crushing events—probably spurred on by watching disaster movies as a kid.

I never did scientific research in high-energy astrophysics per se, but I was involved in the field for many years. Back in 2000, I left my job working on Hubble Space Telescope to move to California and be a part of the Sonoma State University NASA Education and Public Outreach group, headed by Lynn Cominsky. We developed educational products based on several NASA high-energy missions like Fermi, Swift, NuSTAR, XMM-Newton, and more.

It was (pardon the expression) a crash course on high-energy astrophysics, and I had a chance to learn so much about all these amazing astronomical objects and events from some of the top men and women in the field. I wrote tens of thousands of words for the Web, brochures, classroom activities, grant proposals, and even games we created. This was all in the service of educating teachers, students, and the public about the high-energy Universe, but it also filled a need in my own brain to find out as much as I could about all this fascinating science.

Whenever I write about black holes or gamma-ray bursts now, I’m reminded of my time learning about them back then. It’s nice to be able to tie together different times in my life and use them to help me in my writing.

I am deeply honored to accept this award, especially because it comes from my peers in the writing and scientific community, and I thank them sincerely.

Jan. 28 2016 9:15 AM

The Dark Cloud of the Wolf

The space between stars is not empty.

Dark, cold, ghostlike material lurks there, as thin as a politician’s promise. Astronomers call this material “dust,” but don’t be fooled; it’s not like the little tumbleweeds you find under your desk. This stuff is made of grains of minerals and complex carbon-based molecules much like soot, created in the atmospheres of stars and blown out into the depths of space.

In the denser clouds of dust there might be a million particles in a single cubic centimeter of space. That may sound like a lot, but it’s one-ten-trillionth the density of the air you breathe.

Still, over hundreds of trillions of kilometers, even material this ethereally dispersed adds up. These grains and molecules of dust are very good at absorbing visible light, blocking it from passing through the clouds. As it happens, many of these clouds are located in the plane of our galaxy, the parts of our sky where stars are crowded together. When a cloud is between us and those stars, it looks like a hole in space, a place where the galaxy forgot to make stars.

The picture at the top of this article is one such cloud: Lupus 4, a vast filamentary structure 400 light-years away and about 10 light-years across. It was taken with the Wide Field Imager on the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile, and the field of view is about a degree across: twice the width of the full Moon on the sky. That’s staggeringly big. Some people say it looks like a spider, but to me it more resembles some sort of cephalopod, its tentacles reaching out to us …

And that description is more apt than you might think.

Lupus is the constellation of the wolf, located not far from the center of the galaxy in the sky, where dust, gas, and stars are thickest. Lupus 4 is part of the sprawling Scorpius-Centaurus OB association, a loose cluster of massive stars that’s one of the very closest to Earth. These stars are young, and don’t live long; after a few million years they explode, scattering heavy elements into space.

A little while back, scientists studying ocean floor sediments examined a core taken out of the Atlantic Ocean seabed. They found a spike in an isotope of iron, called iron-60, dating to about 3 million years ago. Iron-60 is radioactive with a short half-life, and as far as we know only produced naturally in one place: a supernova. An exploding star.

That means either the material blasted away from a supernova swept over the Earth and deposited that material, or our solar system passed through a region of space where the blast wave from a supernova had stagnated (stopped after plowing through the material between the stars). Since iron-60 decays rapidly, either way it means this must have been from a cosmically young supernova.

As it happens, the stars in the Scorpius-Centaurus OB association are at the right distance to be implicated in this. Millions of years ago, one of them reached the end of its life, blew up, and sent material fleeing outwards at a substantial fraction of the speed of light. Some of that material managed to reach Earth, fall to the bottom of the ocean, and await our notice.

I mentioned that clouds like Lupus 4 appear to be where the galaxy forgot to make stars. But ironically, these clouds are generally the sites of star formation; it’s just hidden from us by the thick soup of dust. It’s possible that the star that blew up all those ages ago formed in a cloud just like Lupus 4 (perhaps in one of its neighboring clouds), and in death managed to physically touch our planet across four thousand trillion kilometers of space.

Like I said. Its tentacles, reaching out to us …