Author: Discover Main Feed

Earth’s placement on one of the outer arms of the galaxy gives us a view of what’s happening in the center.

This news came out a little while ago but I didn’t cover it at the time, and it’s cool enough that it deserves to be covered. I got it from my friends with NASA’s Fermi satellite outreach group. I used to work on Fermi outreach before the satellite launched and was still called GLAST (Gamma-ray Large Area Space Telescope), and it was fun trying to come up with lesson plans and educational efforts based on gamma rays (the Hulk came up a lot).

Anyway, one thing Fermi can do is measure the exact time when high-energy gamma rays hit its detectors. Not too long ago, photons from a distant explosion slammed into Fermi, and it found that all these photons arrived essentially simultaneously from the event, irrespective of their energies.

So what? So, Einstein was right. Check it out for yourself:

Basically, the idea is that some quantum mechanics theories propose that space is irregular, foamy, and bumpy on incredibly small scales, and this means the speed at which photons travel may change very slightly if they are more or less energetic. The difference is so small that it takes very long trips to detect it — imagine two cars traveling at 50 versus 50.5 kph: after a few seconds you’ll hardly see any difference, but over an hour they’re separated by half a kilometer. So the longer the trip, the easier it is to measure.

After 7 billion years, if those specific QM theories are right, two photons should arrive at very different times, but Fermi found that the high energy gamma rays hit Fermi less than a second after the low energy ones. This means that space really is smooth, or at smooth at scales smaller than predicted by those quantum theories. QM is still a solid model for the Universe — after all, solar panels, computers, and nuclear bombs do work — but this means that we need to rethink certain aspects of them.

I love hearing stuff like this. We have lots of ideas on how the Universe works, but we need observations of the Universe to know if we’re traveling down the correct path or not. Fermi has shown us that some of these paths lead to dead ends, and we need to look elsewhere for our journey to continue. And I will guarantee that not only will that journey go on, but we’ll find ever-more roads to investigate as we travel.

After watching Avatar last weekend, I composed a post about being particularly appreciative that James Cameron and his crew so obviously did their homework when it came to much of the science depicted onscreen. I invited readers to share their impressions and many of you came through with terrific examples–some I hadn’t even considered before. So I’ll run through five of the science details I enjoyed most, followed by a few of the best examples from our reader community:

1) Dr. Grace Augustine. Sigourney Weaver’s portrayal of a research scientist was uncharacteristically good. Instead of the typical caricature we see in Hollywood, she wasn’t socially inept (i.e. typical Rick Moranis roles) or out to destroy everything (i.e. Dr. Evil). Instead, Grace conveyed the natural curiosity about the world that I observe so often in colleagues. Also noteworthy, she was funded by a program with corporate interests, but really using the opportunity to pursue her own research. Sound familiar to anyone?

2) The Skull. Did you catch the Toruk skull? It wasn’t onscreen long, but it appeared to have characteristics of both birds and reptiles. I couldn’t tell for sure, but it seemed quite detailed and cool.

3) Bioluminescence. With a background in marine biology, you know I’m going to appreciate that.

4) Scale. If gravity on Pandora is less than that on Earth, larger organisms would be supported.

5) Location. The choice of putting Pandora on a moon in the real Alpha Centauri star system (the closest system to Earth) was neat since scientists are looking at moons for life. The radiation anticipated could be mitigated by superconductivity. Which brings me to…

Those floating mountains. Many comments expressed disappointment with them, however, it’s not quite as implausible as you may suspect. The filmmakers put thought into this: Superconductors expel magnetic field lines, so the effect could make these mountains levitate like magnets away from the surface. (Details here).

There is a great deal more I like about the science of Avatar, but rather than compose an exhaustive list, I’ll quote some examples contributed by readers below the fold…

Phenomenal writes:

Enjoyed the fact it was a moon, different gravity & atosperic composition, the scientists passion for knowledge & care & respect, transduction between plants, several different layers to the food web, imaginative topography such as floating mountains & giant trees, Gaia theory, biomechanics of the creatures locomotion as six-limbed vertebrates, biolumeniscence & colourations of the flora & fauna.

Patrick B. writes:

..great thought went into the physics of the Pandora solar system, to the geology of the planet, to the plants and animals that evolved on the planet, and to the social structures of the Na’Vi.

1- Pandora appears to be a moon orbiting a gas giant. The gas giant can be seen in the sky in several shots in the movie, and you get the sense that the proportions are realistic.

2- Pandora’s atmosphere is not breathable to humans. I loved this! In Star Wars, Star Trek, and just about any other sci-fi film, there are countless planets with human-breathable air, which is not very realistic. The air pressure on Pandora is tolerable for humans, but humans need face masks in order to breath. It seems that the face masks somehow modify the Pandora air, perhaps by filtering out the bad gases.

3- One line in the movie establishes that Pandora’s gravity is slightly less than Earth’s. By adding this line, the film provides sufficient explanation for why Pandora has phenomenon like gigantic trees.

4- There was clearly a great deal of thought put into the diverse plants and animals we find on Pandora.

The Real World writes:

This article is nothing more than an advertisement in a media science magazine.

Huh? This is a blog TRW and I work at Duke.

Lee writes:

I thought it was cool that you could see an evolutionary resemblance between a lot of the creatures. Everything except the humanoids and the rest of the animals, that is. If everything else on the world has six legs (or wings, or whatever), then why would the humanoids only have four limbs? What possible evolutionary advantage could they have for losing them?

Marshall P. writes:

sub-lightspeed space travel! After I left the theater, I was explaining to one of my friends that based on the stated travel time by the cryosleep doctor, and the distance to Alpha Cen, one could work out the ship’s velocity profile consistent with relativity. And few hours later at home, I stumbled upon the web page by the movie staff where they lay out exactly that! http://www.pandorapedia.com/doku.php/isv_venture_star
Someone did their homework on this one. Even the propulsion technology of the ship is quite plausible, given the just one highly speculative step of being able to manufacture large quantities of antimatter for fuel. I especially like the hybrid antimatter/fusion rocket combined with a beam-powered light sail. That’s exactly the sort of complicated trick that real-world engineers would use to reduce fuel and mass constraints on the spacecraft.

kchiou writes:

1) Despite their futuristic tools and their corporate ties, the scientists maintain a childlike curiosity and sheer bewilderment with nature. As a field scientist, that depiction really resonated with me because I see it all the time in the faces of field researchers. Just a thought: do you think Sigourney Weaver’s performance as a scientist was in any way affected by her work on Planet Earth?

2) As an extension of the first point, the scientists are conscious of the sheer wealth of knowledge in the Pandoran ecosystem and are careful not to presume too much. This is much more in line with true science. The way that Sigourney Weaver’s character said “What we THINK we know is . . . ” can be pulled right out of any science lab.

Gary Thomas writes:

I found it very annoying that they got the sound of the ducted fan aircraft so wrong. The whoop whoop sound of a large slow speed rotor on a helicopter is not the sound that counter rotating blades, especially small diameter ducted ones would make.

I don’t know about ducted fan aircrafts, but an interesting observation.

Rich writes:

The floating mountains were very clearly explained in the movie. They even show the unobtainium superconductor floating in a magnetic field several times in the human base, and then there are multiple lines of dialogue about the mountains being in a region of strong magnetic field. It does make me wonder why they aren’t mining the mountains though…Also, it’s refreshing that the scientists are the good guys in the film!

Great work so far everyone, and add any new observations in comments…

The big roundup in Nevada has begun. But rather than being fodder for a old-fashioned Western, this one is kicking up a fight. Yesterday the Bureau of Land Management launched its mission to capture 2,500 wild horses from public and private lands across the state.

Contractors in helicopters and on horseback herded some of the mustangs into corrals in the Black Rock Range, a chain of mountains 100 miles north of Reno, according to a spokeswoman for the Bureau of Land Management. Heather Emmons said she did not know how many horses were captured on the first day of the roundup, which will take two months and stretch across 1,750 square miles in the Calico Mountains Complex [Los Angeles Times].

According to the BLM, the Nevada lands can’t sustain the 3,000 wild horses that now live there, as the population will likely double in four years. So, the agency argues, winnowing the population will sustain the environment and protect the horses, too. But where the horses will end up remains uncertain. Long-term plans call for the mustangs to be placed for adoption or sent to holding facilities in the Midwest. The agency said a facility in Reno was full of adoptable horses, making it unclear when the animals gathered in the latest capture could be put up for adoption [AP].

To say that the helicopter roundup riled up some horse lovers would be an understatement. “To start this immense roundup … on private land where members of the public are forbidden to attend is a brilliant, insidious move on the part of the BLM to hide the suffering and death that they are about to inflict on our mustangs,” said activist Eylse Gardner [San Jose Mercury News]. Activists say that helicopter-assisted roundups frighten the horses and can cause injuries like broken legs, which cause horses to be euthanized. However, a federal judge last week denied a request to stop the operation by ruling that it didn’t violate the law, paving the way for its commencement yesterday.

Opposition remains, in both local activists and celebrity sympathizers—it seems the Rolling Stones aren’t the only musicians with a soft spot in their hearts for “Wild Horses.” Celebrities including singers Willie Nelson and Sheryl Crow and former Playboy models Shane and Sia Barbi have tried to call attention to the issue. “We must act now before the BLM has managed these magnificent animals into extinction,” Nelson said [USA Today].

Related Content:
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Image: flickr / zenera

Folks in Europe, Africa, and Asia can say goodbye to 2009 by viewing a very slight lunar eclipse on the last day of the year: Thursday, December 31. The event lasts for about an hour starting at 18:52 UTC, with deepest eclipse, such as it is, at 19:22.

Only a small part of the Moon will be in the deepest part of the Earth’s shadow, so this is nowhere near a total eclipse, when the Earth fully blocks sunlight from reaching the Moon. However, if you go out and take a look you’ll see the full Moon looking distinctly flattened on one side, and perhaps the rest of the Moon’s surface will look dusky. I’ve made a little image here to show you about how much the Moon will be covered, and approximately where. Like I said, only a small part will be darkened.

Not everyone will see this; North and South America are basically shut out of this event since it happens on the other side of the planet and the whole thing’s over before the Moon rises. The image of the Earth here shows where the eclipse will be visible: if you can see where you live, then you can see the eclipse. The closer you are to the center of the map, the higher the Moon will be in the sky at midpoint of the eclipse.

The next lunar eclipse visible will be in June 2010, but it’s partial and will only be visible in Australia. After that, there is a full eclipse in December 2010 which will be seen by North and South America — though the farther west you are the better as far as decent viewing times go (it’ll be around midnight for me in the Mountain time zone).

Anyway, if you want to learn about lunar eclipses (like what I mean by partial versus total, and what an umbra and penumbra are) then take a look at the Mr. Eclipse site, which has great info.

I’ll note that this last eclipse of 2009 is also a so-called Blue Moon: the unofficial term for the second full Moon in a single month. There’s no real significance to it — the Moon ain’t blue, folks, despite a bunch of news sites already posting pictures of the Moon Photoshopped to look that color without explanation. But the real thing here is that celestial geometry is putting on a small show for you, and what better way to ring in a new year?

Tip o’ the umbra to AstroPixie for reminding me about this!

Never let a group of scientists have too much time on their hands. While a fusion reactor was down for improvements, scientists at the Princeton Plasma Physics Laboratory unleashed their inner child and built a model train track inside the reactor. A toy train then chugged around the track for three days, according to The New York Times:

It was not an exercise in silliness, but in calibration.

The modified model of a diesel train engine was carrying a small chunk of californium-252, a radioactive element that spews neutrons as it falls apart.

In the past, scientists used a stationary neutron source to calibrate the reactor and to make sure it was accurately measuring emitted neutrons, but that doesn’t recreate how neutrons actually bounce around. Tossing a lump of californium on the moving train improved the accuracy 10-fold, according to the scientists.

Researchers at Princeton used toy trains for calibration decades ago in an older reactor, but anytime scientists build radioactive trains, people tend to pay attention.

An no, the train didn’t glow bright green or gain super powers—californium is only slightly radioactive, after all, and the toy train is now chugging around the Christmas tree in the lab’s lobby.

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Image: flickr / drcorneilus

The brains of people who were abused as children and then commit suicide show DNA modifications that made them particularly sensitive to stress.

In tomorrow’s New York Times, I have an article about the Genomic Encyclopedia of Bacteria and Archaea, a new database that’s designed to span the vast diversity of our planet’s microbes. Check it out!

[Update: one of the scientists behind the encyclopedia, Jonathan Eisen, has blogged about the encyclopedia’s history here.]

Image: Flickr

There is really no good way to end a high speed car chase. Shooting out the tires of a fleeing vehicle or laying down old fashioned spike strips are both terribly dangerous. Ramming the getaway car with a police cruiser until it spins out is obviously risky. Thankfully, the government is hard at work on the problem and they’ve come up with a solution that maybe ready by next year, according to the Department of Homeland Security. The technology is named the Safe Quick Undercarriage Immobilization Device, but you can call it SQUID.

“SQUID was inspired by a sea creature and a superhero,” says [Engineering Science Analysis Corporation] president Martín Martínez. Like its oceanic namesake, SQUID ensnares its prey with sticky tendrils. Like Spiderman’s webbing, these tendrils stretch to absorb the kinetic energy of their fleeing target.

Huge amounts of such counterforce are necessary to stop a heavy, swift vehicle: Think Spiderman II, where Spidey stretched his webbing for blocks to halt a runaway passenger train. The force nearly killed him. Martínez took a different approach that would have made Spidey proud: Don’t fight the Force; just stop the axles from turning. Do that and you can stop (almost) anything with wheels.

The technology is capable of stopping heavy vehicles, and in one demonstration it quickly brought a pickup truck moving at 35 miles per hour to a gentle halt. Check out the video below from the U.S. Department of Homeland Security’s YouTube channel (?):

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Video: YouTube / ushomelandsecurity

Wind turbines, energy-efficient light bulbs, and hybrid cars and three of the most iconic products in the lineup of green technologies that can help us build a cleaner world. But in an ironic twist, these technologies all rely on elements called rare earths, which are primarily extracted from environmentally destructive mines in China.

The environmental damage can be seen in the red-brown scars of barren clay that run down narrow valleys and the dead lands below, where emerald rice fields once grew. Miners scrape off the topsoil and shovel golden-flecked clay into dirt pits, using acids to extract the rare earths. The acids ultimately wash into streams and rivers, destroying rice paddies and fish farms and tainting water supplies [The New York Times].

Despite the name, many of the 17 rare earth elements are not actually that scarce, but two heavy rare earths that are vitally important to many green technologies, dysprosium and terbium, do live up to their name. More than 99 percent of the world’s supply of these two elements is currently mined in China. Companies want to expand production outside China, but most rare-earth deposits, unlike those in southern China, are accompanied by radioactive uranium and thorium that complicate mining [The New York Times].

Putting small amounts of dysprosium in the magnets used in electric motors can make the magnets 90 percent lighter; that’s a boon for both hybrid electric cars and large wind turbines, where heavy turbines are placed at the tops of tall towers. Meanwhile, terbium is used in lighting systems that are dramatically more energy-efficient than traditional incandescent lighting. But as prices of these elements have soared in recent years, and as concerns about China’s mines are increasing, companies are beginning to investigate other ways to build the technologies of the future.

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Image: Wikimedia Commons

Telescopes spotted it, computers traced it, onlookers watched it, and students picked up the pieces.

The newest big thing in solar power is a set of solar panels so small that they could be mistaken for specks of glitter.

Researchers at Sandia National Laboratories have produced “microcells” that are thinner than a human hair, which are made from crystalline silicon and use 100 times less material to generate the same amount of electricity as standard solar cells made from 6-inch square solar wafers [Inhabitat].

What’s more, the tiny solar cells could be attached to flexible materials like plastic or cloth, letting inventors dream of a solar power tie that could recharge your cell phone, or a tent that could run electric lights at night.

Says lead researcher Greg Nielson: “With this technology, one can envision ubiquitous [solar-powered] devices.” … In the lab, these hexagonal microcells have achieved photovoltaic efficiencies of about 15 percent, denoting the percentage of light shone on them that is converted into harvestable electricity. High-end commercial-grade solar cells can reap about 20 percent currently, though Nielson thinks the microcells can more than match this [LiveScience].

Even though the tiny solar panels are made of relatively expensive silicon rather than the cheaper materials being used in emerging thin film solar technologies, researchers say that mass-production of the microcells should keep costs low.

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Image: Murat Okandan/Sandia National Laboratories

Quick! Someone call Ray Comfort!

Yup. It’s Jesus in a banana peel. The article has all the usual nonsense, so I’ll spare you the details. But my favorite part is where the banana owner says, “It definitely wasn’t that way when I bought it from [the store]…. “.

<sarcasm>Yes, because once you buy a banana and bring it home, it stays exactly the same forever.</sarcasm>

Sigh. I’ve had bananas go bad on the way home from the store. Bananas are the least stable fruit ever. I bet ten minutes after that picture was taken it looked more like the pareidolia in the kitchen sink.

I suppose there will never come a day when the mainstream media will have an article with a picture like this with the headline, “Random pattern in object appears to look vaguely face-like; owner makes no claim of divinity”. That would certainly be news to me!

Tip o’ the polyphenoloxidase to Mauro Mello, Jr.

Huge-headed humans called Boskops lived in Africa with Homo sapiens until just 10,000 years ago. What happened to them? Shouldn’t their superior intellect have given them a survival advantage? We internally activate many thoughts at once, but we can retrieve only one at a time. Could the Boskop brain have achieved the ability to retrieve one memory while effortlessly processing others in the background, a split-screen effect enabling far more power of attention?

Each of us balances the world that is actually out there against our mind’s own internally constructed version of it. Maintaining this balance is one of life’s daily challenges. We occasionally act on our imagined view of the world, sometimes thoroughly startling those around us. (“Why are you yelling at me? I wasn’t angry with you—you only thought I was.”) Our big brains give us such powers of extrapolation that we may extrapolate straight out of reality, into worlds that are possible but that never actually happened. Boskop’s greater brains and extended internal representations may have made it easier for them to accurately predict and interpret the world, to match their internal representations with real external events.

Perhaps, though, it also made the Boskops excessively internal and self-reflective. With their perhaps astonishing insights, they may have become a species of dreamers with an internal mental life literally beyond anything we can imagine.

A fossil dwarf whale, first discovered in Australia over 70 years ago, had an unusual feeding habit. The whale sucked up mud pies in order to feast on sea bed critters, according to a new study. The fossil whale, thought to be between 25 and 28 million years old, hints that mud sucking might have been a precursor to the filter feeding used by today’s baleen whales [National Geographic News]. Modern filter feeders use what’s called baleen—tiny hair-like structures—to filter their prey from the seawater. The most famous, and the largest, baleen species is the blue whale, and the ancient dwarf whale may be a distant relative, say the researchers.

Oddly, the dwarf whale also had teeth, which the researchers speculate were used to chomp on bulky prey that their tongue and facial muscles slurped off the sea floor. Modern whales with baleen plates eat tiny prey such as krill and are distinct from toothed whales, which include beaked whales and orcas (aka killer whales). The ancient whale, Mammalodon colliveri, had a total body length of about 3m. But it appears to have been a bizarre evolutionary “splinter group” from the evolutionary lineage which later led to the 30m-long blue whale [BBC News]. Researchers say the dwarf whale most likely evolved from much larger ancestors and adds evidence to the theory that proto-baleen whales diversified into many experimental body forms, say the researchers, who published their work in the Zoological Journal of the Linnean Society.

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Image: Carl Buell

If fluid water does persist on Mars, life could be hanging on in thin layers of salty water just beneath the surface.

I received an unusual email from, of all people, the Nobel Prize website editor! He was notifying me that the Nobel Prize folks have started a new series of videos where people get a chance to ask questions of Nobel laureates, who will then answer them on YouTube. Pretty cool, and something I heartily approve of. I love it when people get more contact with scientists, especially ones who are doing research that qualifies them for the Nobel!

They started the series off with astronomer John Mather, the Principal Investigator for the James Webb Space Telescope, who won the prize for his work with COBE, the Cosmic Background Explorer. I worked on that project very briefly, and over the next few years had the pleasure of working with John, who is just about as nice as he can be.

Here’s an example of one of the questions — what happened before the Big Bang — with John’s answer:

There are quite a few more, too. If you have an account on YouTube, you can subscribe to the Nobel channel and find out when they will do the next laureate Q&A, too. Very cool.

What with crooks who post status updates while on the lam and snap self-portraits with stolen iPhones, it seems incompetent criminals find technology irresistible. Our latest tale of blundering criminality involves a Bronx man who is quite adept at stealing electronics, but a bit confused about how they work, according to the New York Post:

Jeremiah Gilliam, 22, was caught after playing a stolen game console online — allowing cops in Pelham, where it was stolen, to trace the IP address to his grandmother’s address, cops said.

There, detectives found dozens of video games, laptops, and GPS devices believed to have been stolen from as many as 200 car break-ins and several home burglaries in Westchester County.

While Jeremiah was online gaming away with a stolen Xbox, the console’s owner, a kid, noticed his system was online while playing on another Xbox. He told his parents, who then called the police.

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Image: flickr / benjamin-nagel

“It’s funny that after 60 years, there are still many things we don’t know about this compound.”

Vanessa Woods is not only one of my dearest friends, she’s also an extremely gifted writer. Currently at Duke University, she studies the cognitive development of chimpanzees and bonobos at sanctuaries in the Republic of Congo and the Democratic Republic of Congo. Next June, Vanessa’s latest book, Bonobo Handshake, will be published–and I can’t wait…

Check out this video and read the description below:

Bonobo Handshake

In 2005, Vanessa Woods accepted a marriage proposal from a man she barely knew and agreed to join him on a research trip to the war-torn Democratic Republic of Congo. Settling in at a bonobo sanctuary in Congo’s capital, Vanessa and her fiancé entered the world of a rare ape with whom we share 98.7% of our DNA. Vanessa soon discovered that bonobos live in a peaceful society in which females are in charge, war is nonexistent, and sex is as common and friendly as a handshake.

A fascinating memoir of hope and adventure, Bonobo Handshake traces Vanessa’s self-discovery as she finds herself falling deeply in love with her husband, the apes, and her new surroundings. Courageous and extraordinary, Almost French meets The Poisonwood Bible in this true story of revelation and transformation in a fragile corner of Africa.