The first Death Star from Star Wars (via Wookieepedia)

Obi-Wan: That’s no moon. It’s a space station.

That space station was the Empire’s first Death Star in Star Wars: A New Hope. Obi-Wan and company had just bounced through a debris field, the remnants of the planet Alderaan. Such an act of destruction would seem impossible to us–it seemed so to many of the movie’s characters until it happened. But perhaps not, say three students at the University of Leicester in England who last year published a study on the subject in their university’s undergraduate physics and astronomy journal.

The study’s authors start off by making some simple assumptions: The planet being fired upon doesn’t have some sort of protection, like a shield generator. And it’s about the size of Earth but solid through and through (Earth isn’t solid, but the planet’s layers would have significantly complicated the math here). They then calculate the planet’s gravitational binding energy, which is the amount of energy required to pull apart an object. Using the mass and radius of the planet, they calculate that destruction of the object would require 2.25 x 10³² joules. (One joule is equal to the amount of energy required to lift an apple one meter. 10³² joules is a lot of apples.)

The energy output of the Death Star isn’t given directly in the movie, but the space station was said to have had a “hypermatter” reactor that had the energy output of several main-sequence stars. For an example of a main-sequence star, the authors look to the Sun, which puts out 3 x 10²⁶ joules per second, and they conclude that the Death Star could “easily afford to output [the energy required for an Earth-like planet's destruction] due to to its tremendous power source.”

It would be a different story, though, if the planet scheduled for destruction had been more like Jupiter than Earth. The gravitational binding energy of Jupiter is 1,000 times that of the Earth-like planet in the study. “To destroy a planet like Jupiter [the space station] would probably have to divert all remaining power from all essential systems and life support, which is not necessarily possible.”

Of course, that assumes that the Emperor wouldn’t be willing to sacrifice a space station full of people to wipe out his enemies. And considering that he was just fine with wiping out whole planets, I’m not sure I’d take that bet.

A composite image of S106, from the Hubble Space Telescope and Japan's Subaru Telescope (Credits: NASA/ESA/the Hubble Heritage Team (STScI/AURA)/NAOJ)

About 2,000 light years away, in the direction of the constellation Cygnus (The Swan), in a rather isolated part of the Milky Way, lies a newly formed star known IRS 4. This star, about 15 times the mass of our Sun, is still so young that it hasn’t yet calmed down; it’s ejecting material at high speed, giving this image its wings. That hydrogen gas, colored blue here, is heated by the star to temperatures of 10,000 degrees Celsius, making them glow. The cloudy, red parts in the image are tiny particles of dust illuminated by the star.

This area of the universe is known as star-forming region S106 and it’s pretty small (well, by universe standards), at only two light years from the edge of one “wing” to the other. The nebula is also home to more than 600 known brown dwarfs, “failed” stars that, because of their size, less than a tenth the mass of our Sun, cannot undergo the nuclear fusion that powers glowing stars.

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The best place to find "aliens" might be Comic-Con (2008, credit; Jim Merithew/Wired.com, via Wired Photostream on flickr)

A 2010 poll found that one in four Americans (and one in five people worldwide) believe that aliens have visited our planet. And many of these people believe that the evidence of these visits has been covered up by the government. Area 51, Roswell, mutilated cows in Colorado—there’s got to be some truth in that, right? And so two petitions were created on the White House We The People site, one calling “for the President to disclose to the American people the long withheld knowledge of government interactions with extraterrestrial beings” and the other asking the President “to formally acknowledge an extraterrestrial presence engaging the human race.”

The petitions easily reached the threshold of 5,000 signatures needed to get a response from the White House. But the signers are likely to be disappointed. Phil Larson, who works on space policy and communications at the White House Office of Science & Technology Policy, wrote in the response:

The U.S. government has no evidence that any life exists outside our planet, or that an extraterrestrial presence has contacted or engaged any member of the human race. In addition, there is no credible information to suggest that any evidence is being hidden from the public’s eye.

He gives a few examples of ongoing and planned research—SETI, Kepler, the Mars Science Laboratory—that may lead to the discovery of alien life and then reminds us that the odds of finding alien life are probably pretty slim:

Many scientists and mathematicians have looked with a statistical mindset at the question of whether life likely exists beyond Earth and have come to the conclusion that the odds are pretty high that somewhere among the trillions and trillions of stars in the universe there is a planet other than ours that is home to life.

Many have also noted, however, that the odds of us making contact with any of them—especially any intelligent ones—are extremely small, given the distances involved.

While reading this, I was reminded of a conversation I had with Cassie Conley last year when I was reported a story about what will happen should we actually find alien life. Conley is NASA’s Planetary Protection Officer; she’s the one who makes certain that NASA missions don’t contaminate other planets and that any sample return missions don’t harm us here on Earth. She told me that after she took the NASA job, some people befriended her in the hopes of ferreting out NASA’s secrets about aliens. “I was dropped as an acquaintance immediately upon their realizing that, in fact, I didn’t have any secrets,” she said. “They were disappointed when they found out there weren’t any.” (But at least she had a good attitude about it all: “It was rather entertaining,” she said.)

I will admit that it is possible that some grand conspiracy exists, that a government or corporation could be hiding this information from us all. (I can’t disprove a negative.) But keep in mind what Conley says: “If you think the U.S. government is that good at keeping secrets, you’ve got a lot higher opinion of them than I do.”

In addition, such a conspiracy would necessitate excluding the scientists most interested and most qualified in this area, and all of them have committed to making a discovery of alien life public. “I think there’s a big misconception in the public that somehow this is all a cloak-and-dagger operation,” says Arizona State University astrobiologist Paul Davies. “It’s not. People are quite open about what they are doing.”

Even the White House.

Anyone dressing up as a mad scientist today? (courtesy of flickr user contains_caffeine)

It’s Halloween and if you don’t have a costume yet, obviously you’ve got little time to put one together. But that’s OK, because we’ve dug up a few ideas for easy costumes with a science theme:

1 ) Mad Scientist: Yes, it’s an obvious one, but it will be easy to put together. All you need is messy hair, a geeky t-shirt (if you don’t have one, just take a plain shirt and write a few equations on it) and/or white lab coat, perhaps some safety goggles or protective gloves, and a glass container (a beaker or Erlenmeyer flask would be nice) with some colored liquid, bubbling away with the addition of some dry ice.

2 ) The Pacific Garbage Patch: This idea, from the Mother Nature Network, requires only some blue clothing and whatever bits of plastic you’ve got lying around the house. Glue or otherwise attach the plastic bits in a large patch to your outfit, get a little background info on the problem so you can inform anyone who asks, and you’ll be good to go.

3 ) Schrödinger’s Cat: This is a classic example of a feature of quantum physics in which something can be in two states simultaneously. Schrödinger’s Cat is in a box and is both dead and alive. For this costume, you’ll need a box to wear (at least over your head, like idea number 1 here) with a flap cut out for your face. Give yourself whiskers and a cute cat nose.

4 ) Squid: There are plenty of reasons to love these undersea creatures. But the ability to make a squid hat using nothing more than paper and a couple of CDs (as seen here on Discoblog) is another.

5 ) Dark Energy or Dark Matter: Find a “My Name Is” sticker and write “Dark Energy” or “Dark Matter” on it. No one knows what either of them looks like, so your guess (whatever you’re wearing) is as good as any other.

(And if you haven’t yet carved your pumpkin, be sure to check out these ideas from around the Smithsonian.)

An artist's conception of the star LkCa 15 and the nearby protoplanet. (Credit: Karen L. Teramura, UH IfA)

Planets form from disks of swirling material that condense into solid bodies. Once only a theory, this formation has now been caught in the act by scientists using telescopes at the W.M. Keck Observatory in Hawaii (a site that should be familiar if you’ve read the Smithsonian story on black holes). The planet’s name is LkCa 15 b and researchers say it’s a protoplanet (below, in blue), still surrounded by cool dust and gas (in red). “We…found a planet, perhaps even a future solar system at its very beginning,” says the University of Hawaii’s Adam Kraus, lead author of the study that will appear soon in the Astrophysical Journal.

The planet LkCa 15 b appears in blue surrounded by cooler dust and gas in red, near the star LkCa 15. (Credit: Kraus & Ireland, 2011)

Kraus and his co-author, Michael Ireland of Australia’s Macquarie University, made their discovery by combining two techniques to cancel out the light from bright stars. The first is adaptive optics, which uses powerful computers to rapidly manipulate the telescope’s mirrors and adjust for distortions caused by Earth’s atmosphere. The second is aperture mask interferometry, and it further improves the resolution of the telescope. “We can manipulate the light and cancel out distortions,” Kraus says. They pointed the telescope at the star LkCa 15, canceled out the star’s light and there it was, a newly forming planet.

“LkCa 15 b is the youngest planet ever found,” Kraus says. “This young gas giant is being built out of the dust and gas….For the first time, we’ve been able to directly measure the planet itself as well as the dusty matter around it.”

Phil Plait, at Bad Astronomy, has more details:

The disk’s hole is about 8 billion km across. Disks like this are seen around other stars, and it’s generally thought that the hole is caused by a planet orbiting inside that region sweeping up material. In this case, that looks to be true! If the planet is in a circular orbit, it’s about 2.5 billion kilometers from its star, a little closer to its star than Uranus is from the Sun (it’s not known if the orbit is circular or elliptical; that’ll take a few years of observations as the planet physically moves around the star and the orbit can be calculated). The planet is much hotter than you might expect, but that’s because it’s so young: material is falling onto it, heating it up. That’s why it’s glowing in the infrared.

…Nothing like this has been seen before in a planet so young! That’s scientifically quite important. Our models of how planets form are complex, and we need detailed observations to see if the models are correct or not. Since planet formation is a process, we need observations of it at different stages, including very early on. That’s crucial, since it represents the transition period between the time before planets start to form in the disk, and the time when the planets are all finished and tidied up. We’ve seen both of those before, so this observation is a first.

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The Very Large Array in New Mexico (via wikimedia commons)

The Very Large Array, a collection of 27 radio antennas out in New Mexico, has a problem—it has a boring name. That hasn’t stopped the thousands of scientists who have used the array since 1980 from making observations of our universe. But with an expansion of the array on schedule to be completed next year, the National Radio Astronomy Observatory, which runs the array, has decided that it’s time for a change.

“Though the giant dish antennas, the unique machines that move them across the desert, and the buildings on New Mexico’s Plains of San Agustin may appear much the same, the VLA truly has become a new and different facility. We want a name that reflects this dramatically new status,” says NRAO director Fred K.Y. Lo. “The new name should clearly reflect the VLA’s leading role in the future of astronomy, while honoring its multitude of past achievements.”

Those achievements include: receiving radio communications from the Voyager 2 spacecraft as it flew past Neptune; key observations of Sgr A*, at the center of the Milky Way, now known to be a black hole; discovery of the first Einstein Ring; as well as contributions to many other investigations of stars, galaxies, black holes and other astronomical phenomena.

In addition, the Very Large Array has often appeared in pop culture, a perfect stand-in whenever a mysterious telescope might be needed in movies such as Contact, Armageddon and Transformers: Dark Side of the Moon. You may even have gotten the mistaken idea that the VLA conducted searches for SETI from the movie Independence Day.

There are several ways to go when naming a telescope. Name it after a famous person in astronomy, like the Hubble, or after a place, like Arecibo. Acronyms are always a favorite in science, like CARMA. Or you could be more creative and go in a different direction, perhaps making up something based on a future goal (the Planet Finder 9000?) or a dream.

If you’ve got an idea for what to rename the VLA, tell us in the comments below and also submit it here by 23:59 PST, December 1, 2011. The winning name will be announced at the American Astronomical Society meeting in Austin, Texas on January 10, 2012.

A combined image from the Chandra and XMM-Newton X-ray observatories of RCW 86, which was determined to have started out as SN 185 (Credits: ESA/XMM, NASA/CXC, University of Utrecht (J. Vink))

Astronomers are getting a bit of a treat this week—they’re watching a supernova exploding 21 million years ago (that is, 21 million light years away) in the Pinwheel Galaxy. That’s pretty close for a supernova (they’re usually around a billion light years away), and you might even be able to see it with a simple pair of binoculars. But what was the first supernova?

OK, that was a trick question. We can’t know what was the first star to explode. But we can look at the first recorded supernova, SN 185.

In 185 A.D., someone in China looked up in the night sky and saw a new star. It sparkled and did not move, so it couldn’t be a comet. This “guest star” stayed in the sky for eight months and then disappeared forever; it was recorded in the Book of the Later Han, which told the history of China from 25 to 220 A.D.

The guest star was a supernova, a star that had run out of fuel and then collapsed in on itself in a thousandth of a second. The core of the star heated to a billion degrees and destructive gamma rays were produced. Neutrinos were generated in huge quantities. Only a tiny fraction were absorbed by the stellar gas, and they had so much energy they ripped apart the outer layers of the star. This violent explosion, which could have been brighter than an entire galaxy, also produced X-rays, gamma rays and ultraviolet light. The resulting shock wave produced radioactive elements such as cobalt and titanium. Any planet too close to such a destructive event would have been torched.

In 2006, scientists using the Chandra X-ray Observatory and the XMM-Newton Observatory determined that the supernova remnant RCW 86 was the leftover bits of SN 185. They calculated how fast the energized shell of the remnant was moving to estimate the original date of the supernova and determined that the star had gone supernova about 2,000 years ago. Scientists had thought RCW 86 might be SN 185 because the remnant’s location matched historical records of the supernova, but previous calculations gave the remnant an age of 10,000 years. It appears those calculations were based on measurements of a part of the shock wave that had encountered a region of dense matter and slowed down.

An artist's concept of what planet TrES-2b might look like (Credit: David A. Aguilar (CfA))

A planet orbiting a star some 750 million light years away is extraordinarily dark, according to astronomers at the Harvard-Smithsonian Center for Astrophysics and Princeton University who report their findings in the Monthly Notices of the Royal Astronomical Society. They used data from NASA’s Kepler spacecraft to study the alien world and found that it reflects only 1 percent of the light that reaches it.

The planet, TrES-2b, is a gas giant about the size of Jupiter. But that’s where the similarities end. Jupiter is cool enough to be surrounded by bright clouds of ammonia that reflect a third or more of the sunlight that falls on it. TrES-2b is much hotter—more than 1,800 degrees Fahrenheit—and lacks the reflective clouds. It’s atmosphere is full of chemicals that absorb light, such as gaseous titanium oxide and vaporized sodium and potassium, which explain, in part at least, the planet’s dark nature. The planet is so dark, it is blacker than anything in our Solar System, blacker than paint, blacker than coal.

“It’s not clear what is responsible for making this planet so extraordinarily dark,” says study co-author David Spiegel of Princeton University. “However, it’s not completely pitch black. It’s so hot that it emits a faint red glow, much like a burning ember or the coils on an electric stove.”

TrES-2b is weird in another way—it is tidally locked, like our Moon is with Earth, so that one side always faces its sun, the star GSC 03549-02811, and one side always faces away.

If you don’t like our choices, tell us yours in the comments. (HT: Geeks Are Sexy)

We haven't had a message from ET yet, but maybe we're not looking in the right way. (courtesy of flickr user Robin Hutton)

The search for intelligent life in the universe took a hit earlier this year when SETI had to put the Allen Telescope Array on hiatus due to lack of funding. (It now appears that SETI may soon raise enough money to get the ATA up and running again.) But then, there’s a good chance that this approach, based on the idea that somewhere in the universe alien civilizations are sending radio messages directed at Earth, may be completely misguided. “In my opinion,” Arizona State University astronomer Paul Davies writes in his book The Eerie Silence, “this ‘central dogma’ simply isn’t credible.” He points out that if even a fairly close civilization, say 1,000 light years away, were to look through a telescope and find Earth, it would see the planet 1,000 years in our past. Why would they bother to send a message to a planet that hadn’t even discovered electricity, let alone built a receiver for such a message?

If listening for radio messages is a bit of a long shot, how else could we go about it? Here are 10 ideas that have been put forth, and even put into practice, by various sources (and if you want more detail, I recommend Chapter 5, “New SETI: Widening the Search,” of The Eerie Silence):

1 ) Optical SETI: Russian and American scientists have been searching the skies periodically for the last couple of decades looking for laser light, which is not only distinguishable from other natural types of light, such as starlight, but could only be produced by an intelligent source.

2 ) Look for huge alien structures: When people bring this one up, the best example is always the Dyson sphere, a hypothetical structure that a civilization would build around an entire star to capture all of its energy.

3 ) Find evidence of asteroid mining: Humans are already looking at the asteroids in our solar system and considering their potential for mining, so why wouldn’t an alien civilization do the same? Evidence could include changes in the chemical composition of the asteroid, the size distribution of debris surrounding it, or other thermal changes that could be detected from Earth.

4 ) Check planetary atmospheres for pollutants: If there are non-natural chemicals, such as chlorofluorocarbons, in a planet’s atmosphere, it’s a sign that there might be someone with technology on the ground.

5 ) Look for signs of stellar engineering: For now, this is the stuff of science fiction, but a civilization capable of tinkering with a star would surely be of interest to us Earthlings.

6 ) Look for an alien artifact here on Earth: Earth has been around for billions of years—who says that aliens haven’t been here before? If they visited long ago, perhaps they left behind something in a difficult-to-reach spot, such as at the bottom of the ocean.

7 ) Find a pattern in neutrinos: Davies points out in his book that neutrinos, those ghostly subatomic particles, are probably better suited for bringing a message over a long distance than either radio or optical signals. A message would have to be simple—transmitted in a sort of alien Morse code—but we could detect it here on Earth.

8 ) Check for a message in DNA: DNA is just another way to encode information. Aliens, or even just an alien probe, could have visited Earth long ago and inserted a message into some ancestral creature. Of course, there are several hurdles to such an idea, as Davies notes—getting the message here, getting it into a critter, keeping it from getting destroyed by mutations over perhaps millions of years—but it certainly an intriguing possibility.

9 ) Find a propulsion signature from an alien spacecraft: Hey, if it worked for the Vulcans in Star Trek, why not us?

10 ) Invite ET to log on: A group of scientists have set up a web site asking for an extra-terrestrial intelligence to send them an e-mail. So far all the responses have been hoaxes, but asking for a shout-out never really hurts.

What bits of the universe are legal to own? (credit: NASA)

If someone tries to sell you the Brooklyn Bridge, you know it’s a hoax. But what about a meteorite, moon or star? Here’s a quick guide to owning anything with origins outside the Earth:

Lunar Property: The 1967 Outer Space Treaty prohibits nations from claiming property rights on the Moon or anywhere else in space (including planets, asteroids, comets and anything else you can think of). Dennis Hope, a Nevada entrepreneur, thinks that the treaty has a loophole, however, and doesn’t prohibit a person—who, after all, is not a nation—from claiming rights to extra-terrestrial objects. And so he claimed the Moon in 1980, later set up the Lunar Embassy, complete with its own government, and started selling. An acre of “prime” lunar property goes for $19.99 (plus $1.51 in tax, $12.50 shipping and handling and an extra $2.50 if you want your name printed on the deed). Good luck trying to claim that land, though.

Lunar Resources: A 1979 treaty set out guidelines for managing the Moon’s natural resources, though hardly anyone signed that agreement. That’s not a problem for now, but it does present an extra layer of uncertainty on any future plans to colonize our nearest neighbor.

Moon Rocks: These might seem to be an obtainable way to own a bit of Earth’s biggest satellite, but you’d be out of luck. NASA owns every bit of the 840 pounds of the stuff that Apollo astronauts brought back to Earth from 1969 to 1972. Scientists can request bits of lunar material to study, but it’s illegal to own or sell any of it. Those who can afford to buy a piece of space history, however, might get a tiny bit of Moon dust if they buy an object used by one of the Apollo astronauts.

Meteorites: In the United States, meteorites belong to whoever owns the property where it lands (although that’s not always straightforward), and then they can be sold or donated wherever the owner likes. Most meteorites originate in the solar system’s Asteroid Belt, but some come from the Moon or Mars, making meteorites the easiest way to own a bit of those faraway places.

Stars: Stars and other astronomical objects have strict naming conventions overseen by the International Astronomical Union (which means that there’s far less fun in these names than in naming critters and plants). That hasn’t stopped any number of companies from selling stars, though. But, as the IAU notes, all you really get is “an expensive piece of paper and a temporary feeling of happiness, like if you take a cup of tea instead of the Doctor’s recommended medicine.”

Scientists have access to other bits of the universe, too, such as a sample of asteroid collected by the Japanese Haybusa mission or pieces of comet brought back by NASA’s Stardust. But for the rest of us, we’ll just have to make do with visiting a museum.

Astrophysicists like to talk about big concepts—like the nature of time, the universe, our very existence—but few make it understandable to the non-astrophysicist crowd. Usually these discussions leave my head spinning, unable to keep track of all of the concepts being flung my way. Which is just one reason why I found this talk from TEDxCaltech so fascinating. In the video, Sean Carroll, a Caltech theoretical physicist (and one of the writers of Cosmic Variance), discusses an array of topics: how entropy is responsible for the flow of time; that the universe is expanding at an accelerating rate and how dark energy fits into that; as well as the future of the universe. And then he suggests that the Big Bang might not have been the beginning.

The ideas fly by so fast I barely had time to ingest one before the next one arrived, and I’ll probably want to watch this over a couple more times to take it all in. But I have to admire anyone who can make dark energy finally make sense for me.

The Allen Telescope Array (courtesy of flickr user brewbooks)

The SETI Institute announced this week that the Allen Telescope Array, with which the institute searches for signals of extra-terrestrials, has been temporarily taken offline due to lack of funding. Tom Pierson, the institute’s CEO, wrote in a letter to supporters (pdf):

Unfortunately, today’s government budgetary environment is very difficult, and new solutions must be found. [National Science Foundation] University Radio Observatory funding for [Hat Creek Radio Observatory, where the ATA is located] has been reduced to approximately one-tenth of its former level. This is compounded by growing State of California budget shortfalls that have severely reduced the amount of state funds available to the Radio Astronomy Lab. Combined, these factors have resulted in the current decision by [the University of California at Berkeley, which operates HCRO] to reduce operations of the Hat Creek site to a hibernation mode, pending future funding or some alternative solution. Hibernation means that, starting this week, the equipment is unavailable for normal observations and is being maintained in a safe state by a significantly reduced staff.

This doesn’t mean the search is dead. Other efforts, such as setiQuest, will continue; other telescopes can continue to search; and the ATA will come to life again once funding can be found. In addition, NASA and other space agencies will continue their searches for evidence of life on other planets. But SETI is perhaps the most famous of the ET hunters, and with the recent discovery of more than 1,200 potential planets that would make interesting listening targets for SETI, shutting down the ATA is somewhat of a disheartening development.

SETI’s scientists are used to thinking long-term, however. After decades of scanning for radio signals, they recently began to search for laser flashes, as I reported in a story for Smithsonian‘s Mysteries of the Universe special issue last year:

“We’re looking for bright flashes that last a billionth of a second or less,” says Jill Tarter, director of the Center for SETI Research and the inspiration for the Jodie Foster character in the movie Contact. “As far as we know, this is something that a laser can do but that nature can’t.” SETI scientists figure that such a pulse would represent an intentional, high-tech, long-distance message: “evidence of somebody deliberately using a laser focused into a large telescope to create a detectable signal over the many light-years between stars,” Tarter says.

The radio signal approach hasn’t turned up much so far, and Tarter admits she doesn’t know what the ideal frequencies might be. Even with the new search for laser flashes, the SETI scientists might be using incorrect technologies, but they still think the effort is worthwhile. As her colleague Seth Shostak says, “Columbus didn’t wait for a 747 to get him across the Atlantic.”

And though SETI scientists have yet to find evidence of extraterrestrials, they are well prepared for success. “Yes, we do have a plan,” Tarter says. “It starts with champagne.”

The constellation Leo, as depicted on a constellation card c. 1825 (via wikimedia commons)

In my neighborhood, some of the street lamps aim their light directly down on the sidewalk and road. Others spew their illumination in a sphere of light, wasting it as it streams into the sky. All those poorly aimed lights add up to 17 billion kilowatt-hours of lost energy each year, costing us around $2 billion. And, of course, they drown out the awesomeness of the night sky.

The National Optical Astronomy Observatory in Tuscon has been documenting this light pollution each spring for the past six years, and they are set to start the next round of GLOBE at Night tomorrow here in the Northern hemisphere, where it runs through April 4 (the program is March 24 through April 6 in the Southern hemisphere this year). Here’s how you can participate:

1 ) Determine your latitude and longitude (write it down). Options include using GPS, Google Earth, the GLOBE at Night webapp.

2 ) Go outside about an hour after sunset and find the constellation Leo (if you’re in the Northern hemisphere) or Crux (Southern). The GLOBE at Night website can provide you with a constellation finder, or you can use your own method. (I’ve got the Planets app on my iPhone, for example.)

3 ) Match your sky to one of the magnitude charts. (You can print them out or access them from your favorite device outside.)

4 ) Use the webapp to report what you saw (or how little you were able to see).

“All it takes is a few minutes for a family to measure their night sky brightness by noting how many stars are missing from an easy-to-find constellation like Leo or Crux,” says project director Connie Walker. “This tells us how much light is directed upwards into the sky.” And it helps to document the patterns of light pollution.

A composite image of Cassiopeia A. The neutron star is the aqua-colored dot in the center. (credit: O. Krause et al., Steward Observatory, Spitzer Science Center, Caltech's Jet Propulsion Laboratory and NASA)

The light from an exploding star traveled for more than 10,000 years across the galaxy before it reached the Earth some 330 years ago. (No one noticed it at the time or, at least, no one wrote it down.) Named for the constellation in which it appears, supernova remnant Cassiopeia A was once thought to house a black hole, but in 1999 images from the Chandra X-ray Observatory revealed the neutron star at the heart of the cloud.

That neutron star is behaving a bit strangely—it is cooling far faster than scientists had expected. Now astrophysicists from the Universidad Nacional Autónoma de México and elsewhere present a new theory, in the journal Physical Review Letters, for what is going on with the star. They say that superfluid neutrons in the star’s core are causing the rapid cooling. A superfluid is a rare, friction-free state of matter, and one that has been studied only in matter at very low temperatures, as with liquid helium. “Discovering evidence for this phenomenon in a neutron star is especially interesting since the temperature, pressure and density of the material are all extremely high,” said study co-author James Lattimer of Stony Brook University.

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An 1849 photograph of Edgar Allan Poe (via wikimedia commons)

I’ve read my share of short stories by Edgar Allan Poe, but I was nonetheless intrigued by a caption in an article in the latest Smithsonian special issue, Mysteries of the Universe. It read: “The hollow Earth theory inspired authors from Edgar Rice Burroughs to Edgar Allan Poe.” I knew that Poe, like many writers, drew from the world around him. But it wasn’t until I started reading up on Poe’s scientific interests that I realized how far they went.

The Hollow Earth theory envisions the planet as something like a huge chocolate truffle with us living on its exterior surface. Inside, the theory states, there are continents and oceans floating on the interior of the outer shell surrounding a gooey, heavenly center. The idea was promulgated by Captain John Cleves Symmes, who toured the country in the 1820s, talking up his fantastical idea and trying to scrounge up funding for a trip to one of the poles where, he maintained, there were holes that would allow access to the center.

Poe used this theory in his sole novel, The Narrative of Arthur Gordon Pym of Nantucket, published in 1938, as well as the short stories “MS. Found in a Bottle” and “A Descent into the Maelstrom.” Each involves a sea journey, though none of the adventurers ever reaches that place where they could enter the center of the Earth.

But Poe’s work went beyond this early science fiction and into the world of science itself. He published a textbook on shell collecting, for example, during a time when these pretty beach finds were intriguing both scientists and obsessive collectors. But his biggest contribution is the prose-poem “Eureka,” published shortly before his death. “I design to speak of the Physical, Metaphysical and Mathematical — of the Material and Spiritual Universe:- of its Essence, its Origin, its Creation, its Present Condition and its Destiny,” he wrote before then pondering such things as Olbers’ Paradox, which argues that the night sky should be so full of stars as to appear as bright as day. It can be hard to read but is truly fascinating.

“No thinking being lives who, at some luminous point of his life of thought, has not felt himself lost amid the surges of futile efforts at understanding, or believing, that anything exists greater than his own soul,” Poe writes in “Eureka.” He was more than a bit of philosopher as well, it seems.

PS — Happy 202nd birthday, Mr. Poe!