Bad Astronomy
The entire universe in blog form

Dec. 1 2015 11:30 AM

Watch Live as the ESA Launches LISA P to Space

Update, Dec. 1 at 17:00 UTC: ARG! Literally within a few minutes of this post going live, I got an email saying the launch has been delayed due to an unspecified technical issue on the rocket. As soon as a new launch date and time are announced I'll update this post.

If all goes well, Tuesday night at 04:14 UTC (11:14 p.m. Eastern U.S. time) the European Space Agency will launch a weird little kind-of-astronomical observatory into space. Called LISA Pathfinder (for Laser Interferometer Space Antenna), it’s a technology testbed, designed to see if some very advanced technology is capable of detecting gravitational waves—and if it does, to pave the way to perform these measurements in future missions on a much larger scale.


OK, first off, the launch will be on a Vega rocket blasting off from Kourou, French Guiana. It’ll be streamed live on ESA’s livestream channel. Once in orbit, LISA P will slowly move itself about 1.5 million kilometers from the Earth toward the Sun, to what’s called the first Lagrange point, where the gravitational effects of the Earth and Sun balance.

Once there, the experiment begins. Inside LISA P are two free-floating cubes. Hardware inside the satellite will measure the positions of these cubes to an accuracy of—get this—a picometer, or one trillionth of a meter. Yes, seriously. The need for such accuracy is critical, because what LISA P is testing is the ability to detect ripples in the very fabric of space and time.

Again, yes, seriously. Albert Einstein was a pretty smart guy, and came up with the theory of relativity, which, among many other amazing things, postulated that gravity isn’t really a force between two objects, but instead a bending of space (and time) itself. Space isn’t just emptiness, the idea goes, but actually a thing with shape and geometry, a cosmic matrix in which we are all embedded.

warped space
Massses warp space, bending it. This is a 2-D representation of a 3-D effect but makes the point well enough.

Drawing by ESA–C.Carreau

If you have an object with mass (like a star) sitting in space, then space bends around it, and a passing object (like a planet) has its path curved. We call that curvature gravity.

But it gets better. If you have two objects revolving around each other, then they give off gravitational waves, which are similar to ripples in water. These waves are usually extremely low energy and long wavelength, making them very difficult to detect. But if you have two very dense objects spinning around each other rapidly, the waves are sharper and easier to measure.

Two black holes fit that bill. So do lots of other objects (neutron star or white dwarf binaries, for example). As these ripples in spacetime move outward, they ever so slightly expand and contract the fabric of space. Now imagine you have two cubes floating in space. As the ripples pass by them (moving at the speed of light), then the distances between the cubes will change ever so slightly.

That’s the technology LISA P is testing. By measuring the distances between the cubes to phenomenal accuracy, it’s hoped that these ripples will be seen. We’ve been looking for them for a long, long time, but like I said, they are very difficult to detect. One instrument on Earth, called LIGO, has been looking for years, and is just now reaching the sensitivity needed to detect these waves.

By putting a spacecraft far from Earth, though, better sensitivity can be achieved. About 10 years or so ago, NASA and ESA were looking into building a full-up LISA, which would be three spacecraft flying in formation, separated by 5 million kilometers, but able to measure their relative position to better than a nanometer (a billionth of a meter), and each with two of those free-floating cubes in them. It was deemed too expensive and difficult, and with a tight budget, NASA had to bail on it.

Happily, ESA didn’t cancel it outright. They scaled it back to the LISA P mission to first test the tech out. Back in the early 2000s I was part of a NASA Education and Public Outreach team involved with several astronomical observatories, and LISA was one of those missions. I was fascinated by the extremely advanced technology for it, and excited by the science it would do. Obviously, I wasn’t thrilled when NASA was forced out due to budget cuts and the ballooning costs of other missions, but it’s pretty gratifying to see this Pathfinder mission finally get into space.

I’ll be watching the launch livestream Tuesday night. Congrats to the ESA team for getting to this point, and let’s hope everything goes well for LISA P!

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Dec. 1 2015 9:00 AM

The Week in Climate Part 2: Grading the Presidential Candidates on Climate

One of the hardest parts of writing about global warming—and there are lots and lots of hard parts—is simply keeping up with the news. Much of it comes in short newsy bits, worth knowing but difficult to write about as an individual full post. Since the 2015 U.N. Climate Change Conference is being held in Paris this week, I’m posting a weeklong series of shorter articles about global warming and its fallout. You can also read Part 1. And read all of Slate’s coverage of the Paris climate talks here.  

In the “I’m shocked … shocked” category, a group of climate scientists graded the presidential candidates on their knowledge of accurate climate change science, and the Democrats came out on top, with the Republicans at best doing badly, and at worst humiliating themselves.


The study was done using anonymized statements made in tweets, interviews, and debates, which were shown to eight scientists. Hillary Clinton came out on top, followed by Bernie Sanders with quite high marks. None of the GOP hopefuls even got a passing grade (closest: Jeb Bush with a meager 64/100).

The only surprise I got was that Donald Trump (15/100) did better than Ted Cruz (a spectacular fail of 6—yes, six—out of 100 points). About Cruz’s (still at the time anonymous) statements, climatologist Michael Mann wrote:

This individual understands less about science (and climate change) than the average kindergartner.

Ouch. Also: true. I’ve written about Cruz’s bizarre and wholly unreal climate stance many, many, many times. He clings tenaciously to long-disproven claims, despite ample opportunity to learn the reality of the situation.

Not to put any of the other Republicans at the front of the class. Bush’s tepid grade is hardly a ringing endorsement, and of course Trump’s bloviating borders on cartoon-level nonsense.

Incidentally, William Ruckelshaus—a Republican himself, as well as the first Environmental Protection Agency chief (appointed by Nixon and reappointed by Reagan!)—has in no uncertain terms condemned the GOP cohort for denying science for political gain. This much is obvious; it’s just gratifying to see another Republican say so.

Nov. 30 2015 11:30 AM

Cyber Monday Among Friends

One of the fun things about being a writer is having lots of friends who write, too. An even funner thing* is that, as a writer, I can help promote their stuff.

Since it’s Cyber Monday—a day promoting online shopping for the holidays—then I’ll take my chance now to help a few pals sell a few more books. And this is more than just cronyism; these truly are good books, even great ones. If you have a geek in your life (and let’s face it: you’re reading this blog, so look in the mirror) any and all of these make perfect gifts.


Furiously Happy

Furiously happy
Jenny is way, way into taxidermy. This is her raccoon, Rory, because of course it is.

Photo by Jenny Lawson/Flatiron Books

I’ll start off with this one, which isn’t really in the geek category, but Jenny is a great person, and a Doctor Who fan, so I’ll allow it.

Sometimes, we can’t find any happiness in our lives. The deep, dark terrors within us make us broken, and devour that happiness.

But sometimes—not always, but sometimes—we can with help overcome those seemingly insurmountable problems, face down the wall blocking us from the light, and find the happiness that is, in fact, there.

Sometimes it’s those flaws themselves that cast that light into relief, show us that despite and even sometime because of our flaws, things can be OK. Better than OK.

That’s the lesson I got from my friend Jenny Lawson’s book, Furiously Happy: A Funny Book About Horrible Things. It may not be the lesson you get, but that’s part of the theme anyway: We all have our dragons to ride. Jenny encompasses that more than anyone I know, a woman who has self-admitted flaws that might keep a normal human down, but instead make her shine so brightly. Watch:

I get choked up watching that every time. Somehow, though, Jenny manages to take these terrible things and spin them into magic, writing a book that is as absurdly funny as it is uplifting. If you’ve read her first book, Let’s Pretend This Never Happened, then you already know that, but if you haven’t, a) go buy it, and 2) buy this one and read them both. She’s a master of turning the horrible into the funny.

On top of all that, Jenny is profoundly NSFW. Man, I love her.   

You’re Never Weird on the Internet [Almost]

Felicia Day
I'd argue the opposite, but I like her anyway.

Photo by Touchstone

If you need an introduction to Felicia Day, then you should have your Internet privileges revoked. Felicia is an actress, a producer of geek content, a gamer, a writer, and just an all-around good person. Also, apparently, a Mad Scientist, too.

It’s easy to think of her as a “celebrity,” someone larger than life. But in her book, You’re Never Weird on the Internet [Almost], she talks candidly of her struggle with mental illness, including a crippling anxiety that has tried to take her down many times. And like Jenny’s book, it’s really funny and charming and endearing (which I think she can’t help).

I will guarantee someone you know has been or is going through the same sorts of things Felicia and Jenny have. At some level, we all have. Buy them these books.

Thing Explainer

Thing Explainer
This explains things.

Photo by Houghton Mifflin Harcourt

For reasons I’ll never quite understand, I have a lot of really smart and creative friends. Even then, I don’t use the word “genius” much, but if it applies to anyone, it’s permanently affixed to Randall Munroe. Creator of Xkcd and What If?, I’ve never met anyone who can absorb knowledge in so many disparate fields, integrate it, and then use it to make funny things.

His new book, Thing Explainer, is a wonder. I already wrote about it when he announced it, so go read that, come back here, and buy the book. You want it.

Full disclosure: I helped a bit with the space section of the book, but you should get it anyway.

Zen Pencils

Zen Pencils

Photo by Andrews McMeel Publishing

Gavin Aung Than is another buddy of mine. He’s an artist who takes inspirational writings and speeches and draws comics around them; he calls his work Zen Pencils. He has a gift for taking strong words and amplifying them with art, and I love his work. I’ve written about his stuff many times. His first book, Zen Pencils: Cartoon Quotes From Inspirational Folks, is great, and now he has a second: Zen Pencils-Volume Two: Dream the Impossible Dream. He has cartoons about Amy Poehler, Chris Hardwick, Isaac Asimov, and many more.

He really is great. His drawings never fail to make me smile and can be profoundly insightful.

Hollyweird Science

Hollyweird Science

Photo by Springer

I met scientist and writer Kevin Grazier a long time ago at a sci-fi convention in L.A. We hit it off right away. He got me a gig as a science consultant on a TV show for kids, and we’ve done eleventy bajillion panels together at various cons.

Like me, Kevin doesn’t like bad science on TV and movies, but also like me he’s more than willing to forgive the odd transgression or two when it helps the story along (and also gives points for stories that at least try to get things straight). Along with Stephen Cass, Kevin wrote a book called Hollyweird Science: From Quantum Quirks to the Multiverse, which dissects the good, the bad, and the ugly in various programs.*

It’s written for the interested layperson but doesn’t shy away from the more mathy and sciencey bits as well. This book is a must-have for any science fiction fan who puts stress on the first word of that phrase.

Hawai’i Nights

Hawaii Nights

Photo by Rogelio Bernal Andreo

Rogelio Bernal Andreo is a master astrophotographer; I’ve posted his work countless times on the blog (and he graciously allowed me to use several of his shots for Crash Course Astronomy, too). He has a book out with pictures he’s taken from Hawaii that shows the beautiful islands combined with the night skies there, and the results are gorgeous. It’s called Hawai’i Nights, and if you’re looking for a lush coffee table book, here you go. It’s available as a digital copy, softcover, and hardcover, too.

Light: The Visible Spectrum and Beyond


Photo by Black Dog & Leventhal

I’ve known Megan Watzke and Kimberly Arcand for forever, it seems. They’re fellow science communicators, working with the Chandra X-Ray Observatory, where they do an excellent job educating the public about X-ray astronomy.

They’ve written a new book called Light: The Visible Spectrum and Beyond, which is pretty self-explanatory. It’s a coffee table book filled with fantastic images explaining all the different flavors of light and what they tell us about the Universe. It’s written in clear, readable text, and it’s entertaining as well as educational. I just checked the price, and it’s a flipping steal at $19.22! Hurry!

Breakthrough!: 100 Astronomical Images That Changed the World


Photo by Springer

I’ve featured Robert Gendler’s astronomical images on my blog here many times. He’s put together a book with Jay GaBany called Breakthrough!: 100 Astronomical Images That Changed the World. This is more than just a pretty picture book; they go through the history of photography and astrophotography, showing important pictures that really did change how we view the heavens.

I learned a lot reading this, and it was fascinating. Examples: The first known photo was taken in 1826/7, and it was an eight-hour exposure using a camera obscura. The first astrophotograph was taken of the Moon in 1845, and was destroyed in a fire. It goes on like that, with very cool photos loaded with information about them. They go through the history of technological improvements over time, and by halfway through the book you’re in the modern era of digital color imagery, and your jaw will hang open in awe at the progress we’ve made.


Because why not: I wrote some books, too. Bad Astronomy, Death From the Skies!, and Nerd Disses are all still available, and I think they’re pretty good.

So that’s what I have for you. Mind you, this is a small slice of what’s out there, of course. If you have a favorite science/geek book, then feel free to leave a link in the comments! The point of all this is to share the joy and wonder, so go ahead and share them.

* I am a professional writer, and I used that word; therefore it is a word.

*Correction, Nov. 30, 2015: This post originally misspelled Stephen Cass’ first name.  

Nov. 30 2015 9:15 AM

The Week in Climate Part 1: Remember When October Was the Start of Fall?

One of the hardest parts of writing about global warming—and there are lots and lots of hard parts—is simply keeping up with the news. Much of it comes in short newsy bits, worth knowing but difficult to write about as an individual full post. Since the 2015 U.N. Climate Change Conference is being held in Paris this week, I’m posting a weeklong series of shorter articles about global warming and its fallout. And read all of Slate’s coverage of the Paris climate talks here

2015 has been a hot one. The hottest, in fact: It’s a cinch to be the hottest year on record. Several months this year have been the hottest of those months on record—looking at each month since 1880, 2015 had the hottest February on record, as well as the hottest March, May, June, July, August, and September.


We can now add October to that list, with a vengeance: It blows any previous October over the past 135 years out of the water, about 0.2 C hotter than the previous record holder … which was October of last year, in 2014.

global temperatures
The average monthly global temperature for just October, going back to 1890. The trend should be obvious, even to a Texas congressman.

Graph by Tamino, by way of the Japan Meteorological Agency

Note the trend in that graph: up, up, and away. And October 2015 was about 0.4 C hotter than the trend. Note too that this comes from two different agencies; both the Japan Meteorological Agency’s and NASA’s numbers agree.

As Tamino points out in that post linked above, October 2015 had the highest temperature anomaly (deviation from average) ever seen*. More than any July, any August. Think on that.

Incidentally, the faux “pause” is in the news again, mostly because of the fanatical crusade by Rep. Lamar Smith, R-Texas, against reality. To drive home just how embarrassingly wrong Smith is, a sixth study came out showing the “pause” doesn’t exist—and that’s the sixth study just this year. The Berkeley Earth group has chipped in as well, showing we’re warming up right on schedule. Even Smith's hometown paper lambastes him for his overreach and abuse of power.

Smith is not just wrong, he’s dangerous, pressuring scientists, sowing discord, and wasting great gobs of taxpayer money. Thanks to gerrymandering he’s unlikely to be voted out of office in Texas, but if the Republicans lose their House majority, he will no longer be chairman of the House Committee on Science, Space, and Technology … and the U.S. will no longer be quite as big a global laughing stock when it comes to politics and science.

Kathryn Sullivan
Dr. Kathryn Sullivan, during one of many stints as a civil servant.

Photo by NASA

I’ll add that Kathryn Sullivan, director of the National Oceanic and Atmospheric Administration, the environmental agency under attack by Smith, wrote a letter to Smith defending science and the scientists under her leadership, detailing his politically motivated (and fossil fuel–funded) shenanigans. In that letter, she writes (emphasis mine);

Finally, Mr. Chairman, let me assure you that I am not engaged in our associated with any “politically correct agenda”. I and the entire NOAA team take seriously the charge to provide the best environmental science and reliable data to the nation and the world. Our work is relied upon every day to drive commerce and to protect public safety and national security. I proudly serve President Obama, as I proudly served President Reagan, President Bush, President Clinton, and President Bush before him. I am a life-long public servant profoundly dedicated to using science to inform decision-making in the best interested of the nation. I have not and will not allow anyone to manipulate the science or coerce the scientists who work for me.

Holy. WOW. I know she’s defending the allegations about those scientists in that last line, but it also reads very much to me like an accusation directed at Smith.

Dr. Sullivan is a freakin’ national hero. When Smith’s comeuppance comes, and this long global nightmare is behind us, I hope she receives a medal for defending reality in this way.

*Correction, Nov. 30, 2015: I originally wrote that October 2015 was the hottest month on record, when it had the highest temperature anomaly on record.

Nov. 29 2015 9:30 AM

Adam Savage, Still Untitled

My Close Personal Friend Adam Savage™ does a lot of fun stuff with the folks at, including a podcast with Tested founders Will Smith and Norman Chan called Still Untitled: The Adam Savage Project. The three of them ostensibly have a topic to cover, but they always seem to wind up all over the place in the discussion, which is pretty much how all my conversations with Adam go.

It’s pretty entertaining, as you’d expect; getting three smart, interesting people together to talk about stuff is generally a good listen. But their episode from Nov. 24, titled “So About That UFO,” is especially good, for two reasons. One is that they talk about the Trident missile launch from early November that freaked so many people out in California.


The other reason is that they spend a full minute talking about what a great guy I am. Modesty prevents me from agreeing with them whole-heartedly and praising their obvious excellent taste, so instead why don’t you just give it a watch?

The good part starts at 4:07. Seriously, it was very kind of them to say such wonderful things, and honestly, back atcha, gents. I got a chance to hang with all three of them for a while at San Diego Comic Con this past summer, and it was a lot of fun. 

Untitled is great, and you can find it on the Tested site linked above, or the audio-only version is on iTunes. Subscribe! Enjoy!

Nov. 28 2015 9:30 AM


Back in the olden days, when the Sun was slightly cooler and the Universe a fraction smaller, I lived in Virginia. At the time (and apparently still today), for a little extra money you could purchase a “vanity” car license plate, with up to seven letters on it. I like this idea, and it’s sometimes fun to try to figure out what other people’s plates mean.

As a bit of silliness, I decided to get UVULA, because why not? I happen to have one, and you probably do too, and I used to (and apparently still today) like to do things just because they’re off-kilter and weird.


So I filled out the form at the DMV, submitted it, and waited. After a few days I got a letter in the mail telling me my request was denied. No reason was given. Now, I happen to know that if the plate you wanted was already taken, they’d tell you (that happened to me once). So why did they refuse me?

To this day, I don’t know. But I have my suspicions. Despite its latitude, Virginia still thinks of itself as a southern state, and a genteel one. I strongly suspect someone at the DMV was confusing a uvula with a vulva, and denied me on the grounds of their own mistaken prurient metathesis.

Ah well. I went with another plate idea, and never looked back.

I’m reminded of all this because my friend, Hank Green—who himself, I presume, has a uvula—just made a SciShow episode about the dangly little throat projection. I have to admit I was never an expert on such things, but I was still surprised at the versatile little appendage and the multiple roles it plays in the back of the mouth.

So there you go. I suppose it’s easy to belittle the uvula, but you do so at your own risk. I’ll personally never downplay it again.

Oh—as for my license plate dilemma, I finally settled on one that befit my greenish streamlined Datsun B210: KLINGON. You can make fun of me if you want, but it was the envy of the Old Dominion. I stopped at a red light once, and a guy pulled up next to me. He caught my eye and said, “I wanted KLINGON but they told me it was taken!”

I laughed, yelled “Q’Plah!”, and drove away. In my rearview window I could see his mouth hanging open, but sadly I couldn’t see his uvula myself.

Nov. 27 2015 9:30 AM

Black Friday … on Mars

Today is the day after American Thanksgiving, considered to be the first shopping day of the Christmas season. Due to the onslaught of eager shoppers to stores, it’s been nicknamed Black Friday.

It’s not restricted to the U.S., though. The Curiosity rover is having its own Black Friday on Mars—in this case, a bit more literally: It’s reached the edge of the Bagnold Dunes, a windswept region in the vast Gale Crater with huge, towering dunes.


The image above was taken Nov. 25, 2015 (also called Sol 1174—a “sol” is a day on Mars, which is about a half-hour longer than an Earth day, and Curiosity has been on Mars for 1175 sols as I write this). Look at it! You can see the flat, grayish rocks in the foreground, and distant hills in the background, but the view is dominated by lush, gorgeous, rippling dunes (check out this mosaic of images showing a much wider angle, too, because wow).

The dunes are dark, likely due to the sand being basaltic—a dark rock created when lava cools. Over billions of years, the exposed Martian basalt has eroded, creating grains of sand that can be blown around by the wind. But not easily!

Mars has an atmosphere, but the pressure at the surface is less than one percent that of Earth. It has winds, but even though they can move rapidly, the air is so thin they don’t have much force to them. Still, it’s enough to blow around the ever-present Martian dust (made mostly of iron oxide, giving it a pinkish-red color … after all, it’s rust!), and finer grained sand particles.

Dune fields litter the surface, but a lot of them are inactive; the wind there isn’t enough to move the sand around. But some fields are active, and the dunes can be seen to move over time. At Bagnold, the dunes migrate at roughly 0.4 meters per year—a little over a foot annually. That’s not much, but it’s measurable.

Curiosity location
The arrow marks the spot where Curiosity was the day before the dune shot was taken (the most recent map available as I write this). It sits on a "peninsula" of rock between two dune fields, part of the much larger Bagnold field. The image is roughly 500 meters wide, for scale.

Photo by NASA/JPL-Caltech/Univ. of Arizona

These dunes are a juicy target for Curiosity. It’s the first time an active extraterrestrial dune field has ever been examined in situ, for one. For another, examining the material will tell scientists on Earth what minerals are in the sand, of course. Measurements from orbit show that there appear to be some minerals located in some parts of the dune field but not in others. Why?

Also, as wind blows the grains it sorts them naturally by size. The distribution of grain sizes around the dunes will indicate how the winds blow, how the grains deposit onto the ground, and more.

The dune field is pretty big, kilometers across. It’s right on the path of the rover, near the foothills on the northwest flank of Aeolis Mons, aka Mount Sharp, Curiosity’s eventual goal. It’ll have to cross the dunes to get to the mountain.

I’m personally thrilled by this shot, and I’ve been waiting for this for a long time. I love dunes on Mars! They’re spectacular, and fascinating.

But more than that, they’re so Earth-like in so many ways. The shapes—horseshoe-shaped barchans dunes, or the more stereotypical transverse dunes in the picture above—look achingly like those on our own fair planet.

Mars was once wetter, warmer, and had thicker air. Now it’s all gone. That’s because of eons of pummeling by the solar wind, the flow of subatomic particles from the Sun. The Earth has a magnetic field, protecting us from that, so we’re still warm and wet, even after 4.56 billion years.

If you want to be thankful for something, be thankful for that. And also that in some places, Black Friday is actually and truly a beautiful thing.

Nov. 26 2015 9:30 AM

Happy Goatsgiving

There’s a very long list of things I feel thankful for this holiday, far too many to actually itemize. But somewhere on that list, well above the median line, would be these goofy creatures:

We moved out to the country outside of Boulder, Colorado, a little while ago, and there was some extra space in the yard where the previous owners of the house had a small horse barn. We had no use for it, really, and couldn’t decide what to do with it. Then one day we were watching adorable goat videos, and my wife got this look in her eye …


And that’s how I became a goat person. We have two Nigerian Dwarfs and two pygmies. We picked up Clayton Forrester, one of the Nigerians,* when he was still being weaned, so we bottle-fed him goat milk for a week or so. He still likes to sit on our laps and cuddle while he chews his cud. It’s ridiculously cute:

Seriously. C’mon. There's also this

I post pictures and videos of these dorks all the time on Instagram; follow me there if you want to see them. And you do.

I love these silly animals, and I love to share their antics with people online. It may not save the world, but you know what? Every little bit of joy we share, no matter how small, incrementally makes the world a better place. If a million people do that, even once or twice a week, it would add up.

Happy Thanksgiving, folks. Make the world better, even just a little.

* The other goats are Jack, Batman, and Sam. Someone asked me if Jack and Sam were from Stargate SG-1, and I could've kicked myself for never seeing that. But no, Jack is actually Jack Burton, from the single greatest movie ever made. I like to think that Clayton is named after a character in another favorite movie, but my daughter named him, so it's probably for this guy.

Nov. 25 2015 9:30 AM

On the Anniversary of Two Scientific Revolutions

This week marks the (very round number) anniversaries of two of the most important scientific papers ever published.

One you’ve heard of—or at least, you’ve heard of the author and its concepts. The other you probably haven’t. Yet it is equally as important, and tells as great a tale.


First things first: On Nov. 25, 1915—100 years ago Wednesday—Albert Einstein submitted a paper to the Proceedings of the Prussian Academy of Sciences in Berlin titled, “Die Feldgleichungen der Gravitation,” or “The Field Equations of Gravitation.”

If that doesn’t sound familiar, maybe it would help if I said that this paper laid the groundwork for Einstein’s General Theory of Relativity.

Oh, right. That paper.

Einstein published his Special Theory of Relativity in 1905. That groundbreaking work showed that space and time were relative, and that if you moved near the speed of light relative to another observer you’d see these two properties very differently. Since then, the Special Theory has since been experimentally verified countless times.

After publishing it, Einstein started working out how to add gravity to this mix. That’s extraordinarily difficult, and the math fiercely complicated. It took him many years, but he submitted the paper in November 1915, and it was published in the next month. In it, he made a startling and fundamental claim: Gravity is not really a force as had been thought, but instead is a warping of space caused by matter.

Sound esoteric? Well, that’s because it is, a bit. Centuries earlier, Isaac Newton had proposed his theory of universal gravitation, describing gravity as a force, attracting one object to another. It depended on their mutual masses and distance from each other. Newton’s idea works pretty well, and in fact we still use it today to plot courses for spaceships!

The term “force” is difficult to accurately define in layman’s terms,* but you can think of it as some sort of connection between objects, attracting them or repelling them. That’s how Newtonian mechanics works out.

But Einstein’s General Theory changed all that. He found that gravity is not a force between two objects, but a property of space itself, a geometric bending or warping of it. It’s usually described this way: Matter tells space how to bend, and space tells matter how to move.

A smiling lens
This smiling galaxy cluster is actually the product of gravitational lensing: the warping of spacetime by a foreground clump of galaxies distorting the path of the light coming at us from a background clump of galaxies. Click to informenate.

Photo by NASA and ESA

It was a fundamental shift in how we thought of space and matter, and fit right in with Einstein’s previous Special Theory work in showing that space and time were connected. Their implications are wide-ranging as well; for example, the solutions to these General Theory field equations describe the structure of space, and naturally predict the existence of black holes. They also predict the existence of gravitational lensing (which we’ve seen, and which led to a confirmation of the existence of dark matter), gravitational radiation (which we’ve detected indirectly), and gravitational time dilation (which we’ve also seen).

An even more profound impact of these equations is that they lead the way to understanding how the Universe itself formed and evolves, and even of its ultimate fate.

Heck, without the General Theory your map app wouldn’t work!

So, yeah. It’s kind of a big deal.

The second anniversary we’re celebrating now is no less in stature, and has an equally deep practical impact on the world.

One hundred fifty years ago, in late November 1865, James Clerk Maxwell published his paper called “A Dynamical Theory of the Electromagnetic Field,” and in it he wrote down a set of equations we now call Maxwell’s equations, which should hint at their importance. Why? They describe how electricity and magnetism are two sides of the same coin, actually the effects of a single force called electromagnetism. Up to that point they were treated separately. Maxwell united them.

The importance of this can’t be overstated! His equations show that electricity can be used to induce magnetism, and vice-versa. We generate electrical power based on this. He showed that light is itself a wave, traveling through space as an oscillating electromagnetic field. Ever heard of the electromagnetic spectrum? Yeah. That’s from Maxwell. His equations show how light behaves, and in fact you can derive the speed of light from these equations if you can measure some other fundamental properties of space.

The spectrum of the Sun; thanks to Maxwell we understand how light behaves as a wave, which led to fundamental breakthroughs in astronomy and physics.

Photo by N.A.Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF

It is no exaggeration to say that Maxwell’s equations are at the very foundation of our modern civilization: computers, electrical systems, global communication—all of this comes straight out of these equations. Einstein’s ideas about relativity derive from them as well.

But there’s more to this story. Maxwell wasn’t a university scientist, working under a research grant to investigate the disparate fields of electricity and magnetism. Nor did he set out to revolutionize the entire planet’s civilization. He was just a curious person, someone who delighted in nature, who was puzzled by how it works, and who wanted to understand it.

And this led to the economic basis of a world.

This story is lovely and wonderful, and was best told by Carl Sagan in his opus, The Demon Haunted World: Science as a Candle in the Dark. I strongly urge you to buy and read that book; it’s magnificent, and many (including me) consider it Sagan’s best work. In one chapter, he talks about Maxwell and his equations, and it’s a paean to allowing scientists to study the Universe unfettered by politics (academic or governmental), allowing their imaginations to guide them.

In many fields of science there must be moral and ethical guidance, of course, but in theoretical physics it is the math and physics themselves that are the guide. Maxwell followed them and revolutionized a world. Einstein followed them and revolutionized our thinking about the Universe.

And today we celebrate the anniversary of both.

For science!

Although, in this case, one could quote Kenobi et al., 1977: “[A force] surrounds us and penetrates us; it binds the galaxy together.” While widely admired and quoted, many find Kenobi’s dabbling in mysticism a bit off-putting.

 To be fair, scientists before Maxwell knew that electricity and magnetism influenced each other, but Maxwell quantified it, defined it, and it’s from there that our modern power systems are derived.

Nov. 24 2015 12:21 PM

Blue Origin Milestone: Rocket Lands Safely After Trip to Space

Jeff Bezos’ rocket company Blue Origin just surprised everyone by revealing its New Shepard* rocket reached an incredible milestone on Monday: In a test run, the rocket took off vertically, reached space, then landed again vertically minutes later.

The rocket launched from their site in west Texas, accelerating to a top speed of about 4,600 kph, and achieving an altitude of more than 100 kilometers, the technical height defined to be the start of space (called the Kármán line). They also deployed the crew capsule at a height of about 6 km above ground, which parachuted safely back to Earth.


Blue Origin put together a nice—if somewhat misleading—video of the event. I say that because in the middle of the real footage they inserted CGI animation of a crew inside the rocket’s capsule; this was an uncrewed flight. Still, the video is cool:

I like the shots of the landing from various angles at the video’s end; it looks more like a Hollywood sci-fi movie than reality! But real it is. The descent is unnerving; the rocket engines don’t reignite until it’s only about 1,600 meters above the ground, and it decelerates pretty hard. That saves a lot of fuel and makes perfect sense, but it’s a little scary to see it! Still, the rocket performed extremely well, and landed only a little over a meter from the center of the launch pad. Amazing.

Blue Origin attempted a similar test flight in April, but the landing system hydraulics failed and the booster crashed. Apparently, and happily, this issue has been addressed.

So congratulations to Jeff Bezos and his team on this incredible test! This is very exciting to see.

New Shepherd
A different angle on the landing. The Sun and tilted horizon are on the left.

Photo by Blue Origin, from the video

However, I’m seeing some confused coverage of this event, and I want to clear a couple of things up.

First, yes, this launch is a big deal! It shows that Blue Origin is making excellent strides towards commercial space launches, a field currently dominated by SpaceX. Getting up to the Kármán line is a major achievement at all, let alone successfully deploying the capsule and then landing the rocket again. SpaceX itself is based on the idea of competing against big government contractors, so competition for them is good.

Bezos himself took to Twitter to announce the success, and made a subtle dig at Elon Musk and SpaceX at the same time:

I smiled, but I have to point out that, as great a technical achievement as this was, what Bezos has accomplished here is quite different than what Musk has been attempting.

The Blue Origin New Shepard is a suborbital rocket, designed to go straight up into space and back down again. The SpaceX Falcon 9 is an orbital rocket, which takes vastly more energy (in other words, much higher speed) to achieve its goal.

Musk responded on Twitter pointing this out:

He’s right. Landing a booster from an orbital flight is hugely harder than from a suborbital one. For orbital flights, the booster not only has to move far faster, it also will have a large horizontal speed relative to the ground to get to orbit, so slowing it is more difficult as well. SpaceX has not yet achieved a successful landing this way, but what they’re doing is literally an order of magnitude more difficult than what Blue Origin did.

Then, in my opinion, Musk made something of an unfair comparison himself. He tweeted:

True, but Grasshopper (a test vehicle designed to launch and land vertically) only got 744 meters above the ground, wasn’t designed for high-altitude flights (it’s a testbed for the F9 landing tech), and didn’t deploy a capsule. The later F9R tests based on Grasshopper were very successful as well, but only got a kilometer off the ground. What Bezos did yesterday was far more technically difficult.

Update, Nov 24, 2015, at 18:00 UTC: Musk has continued to tweet about this, correctly pointing out that suborbital flight and landing has been done before by SpaceShipOne and arguably the X-15 rocketplane. Musk also noted the series of water landing attempts using the F9 booster.

Mind you, suborbital flights are important. It’s more than just a tourist attraction (though a pricy one); real science can be done on such flights, even though weightlessness only lasts a few minutes. Blue Origin looks to be getting quite close to having the ability for these kinds of launches.

The company is known for secrecy, tending to announce achievements only after they’ve been reached. That’s understandable, and it can work to Blue Origin’s advantage in the media as a tortoise-and-hare story (one I think Bezos is happy with). That means details about their future goals are unclear, but the goal itself is obvious: getting in on the lucrative orbital satellite market as well. As I pointed out, the physics of this is quite different, and it’s a long journey there … but they just took a solid step in the right direction. Up. And back down again.

Correction, Nov. 24, 2015: I originally misspelled the rocket as New Shepherd; but it's punningly named after Alan Shepard, the first American in space.