Centuries ago the stars were believed to reside just beyond the planets of our solar system.It never fails to astound me how big the Universe is—how far away even the nearest stars are, let alone other galaxies scattered from here to near infinity….

How do we know how far away celestial objects are? This shouldn't be taken for granted, as it's not as straightforward as sounding the depth of the ocean floor with sonar, or determining the range to an object by bouncing radio waves off it and timing the reflection.

In fact, we have "pinged” the nearest celestial objects with radar to determine their distances very accurately. Examples are the Moon and Venus, where round-trip lightspeed travel is measured in seconds or minutes.

Before radar, the scale of the Solar System had to be determined geometrically, by observing events like Venus or Mercury transiting the face of the Sun from different locations on Earth and triangulating. Even this technique requires telescopes, which we've had only four hundred years. Before that, figuring out distances to just about everything except the Moon was mostly guesswork. In fact, it wasn't too many centuries ago that the entire Universe was believed to be not much larger than the Solar System—the Sun and it's nine…excuse me…eight planets—as we know it today.

Once the distance from Earth to the Sun was figured out, that length (the "Astronomical Unit”) in effect became a basic measuring rod for working out distances to everything else, by one means or another.

As Earth orbits the Sun, the direction from which we see stars shifts minutely, and we can observe a small change in a star's position compared to the more distant "background” stars. You can see the same effect by holding a finger in front of your face and looking at it alternately with one eye, then the other.

The geometry of this observation is a simple triangle, whose base is the distance between your eyeballs and whose legs are the lines from each eyeball to your finger. By knowing the length of the base, and observing the change in viewing angle against the background, the length of the legs (distance from your eyeballs) can be calculated.

In the case of Earth and a nearby star, the "eyeballs” are the Earth at two ends of its orbit around the Sun (six months apart) and the "finger” is the star.

But this measuring of distance by "trigonometric parallax," as it's called, only works for the nearest stars, as the minute shift in the star's apparent position diminishes with distance.

As astronomers learned more about the distance to nearby stars, they determined how to relate their temperature and mass to their actual brightness, and it became possible to estimate the distance of many stars by measuring their apparent brightness, with an understanding of how the brightness of light weakens with distance.

To measure the depths of space between us and galaxies far, far away, in which individual stars are indistinguishable from the overall galactic glow, we can turn to certain types of supernovae: individual stars that temporarily shine brightly enough to be observed and measured. Like the flare of a match struck in the dark night, the brilliance of the flash reveals how far away the striker stands.

We have built up our knowledge of the Universe's vastness over the past couple centuries, working out the problem from the near to the far. Even as science and technology have made the world on which we live smaller, it has done exactly the opposite to the Universe….

Searching for tadpoles in Arroyo Viejo Creek at the Oakland Zoo.

It Day #2 of Nature Play, a new Oakland Zoo ZooCamp program that I have been assigned to teach. I know all about “Nature Deficit Disorder” and “No Child Left Inside”. I have read “Last Child in the Woods” and even blogged about the issues, but now I find myself out in nature with 12 curious and excited children, and I have no idea what will happen.

Nature Play was created in response to childrens’ desire to experience true nature – to look up at trees, observe tadpoles and connect with wildlife in their own backyard. The idea behind Nature Play is to offer the campers supervised and loosely facilitated exploration outdoors that is self directed.

Parents were so game to give these simple pleasures to their children, this program sold out.

Now, here we are. Our afternoon agenda is creek time and fort building. It is a beautiful afternoon at Arroyo Viejo Creek, a small tributary that runs through the zoo grounds. Though there are tigers, lions and elephants close by, this is where the campers are most excited to be. I have given minimal direction: look, listen, smell and feel, and record something in your nature journal. They have nets, jars, binoculars and wildlife guides, and one hour.

Immediately the group swarms to their favorite spot that they discovered yesterday. It is near one of the outdoor classrooms and features a giant, ground-leaning willow tree to crawl under, two logs that rest across the creek to climb over and water loaded with tadpoles and water gliders. I watch and listen myself.

“There are 1000 water striders here! They are riding on top of each other.” “No, that is a shadow”. “I am crossing the log by scootching” “I will help you”. “I found a secret trail!” “I am putting this leaf in my journal”. “I can write with a rock.” “I heard a frog!” I am a frog!” “The sun makes me silly and happy.” “I see tadpoles!” “Let’s call this place Willow Cove.” “I don’t want to go home.”

A few things amazed me about this hour. One, they were never bored. They went on and on with their play and exploration in this small area with gusto the entire time. They were imaginative, inventive and stimulated. Two, they learned. They learned that frogs are quiet when they are noisy. They learned that they could balance better holding their arms out. They did not need my fascinating animal facts to gain knowledge. Three, they truly and intuitively cared about the habitat. They picked up a couple of pieces of garbage, told each other not to handle amphibians and put rocks back where they found them without being told. Four, and most interestingly, they got along fantastically. Earlier in the day there were a few squabbles over this or that, but out here, they helped each other, supported each other and shared the nets like pros. They seemed to be at peace.

A little later at Fort Building, the group divided into two as they followed two natural leaders and their fort visions. As we debriefed about the two forts, they came to the conclusion (themselves) that tomorrow they should build one fort with all the materials, then sit in it and tell stories about animals.

I saw it all with my own eyes. This nature stuff works. Now this explorer is going to sleep. I am exhausted!

(left) A cell imaged with an optical microscope. (right) The same cell imaged by allowing the cell to absorb UCNPs and then irradiating it with infrared light. Each nanocrystal is one thousand times smaller than the width of a human hair. Image courtesy of PNAS."Like a silent black mist, nanoparticles began to come into the room underneath the west door…Inside the room, the particles appeared to spin and swirl aimlessly, but I knew they would self-organize in a few moments."

Thus proceeds Michael Crichton's 2002 thriller, Prey, as the protagonists face off against a malicious swarm of flesh-hungry nano-robots that are the offspring of a most unholy marriage of biological, computer science, and engineering research efforts.

Real science capabilities lag somewhat behind, but researchers succeeded recently in demonstrating an exciting new class of nanoparticle with potential applications in biological imaging. The new crystals, more formally known as lanthanide-doped upconverting nanoparticles (UCNPs), were fabricated and studied under the direction of principle investigators Bruce Cohen and James Schuck at Lawrence Berkeley National Laboratory's Molecular Foundry, and results were published on June 18^th in a paper by Shiwei Wu and others in the Proceedings of the National Academy of Sciences (PNAS).

Happily, while Crichton's nanoparticles coordinated an attack on a your vital organs, these particles behave more like benign light bulbs. After allowing a living cell to absorb the UCNPs, researchers shine infrared laser light on the cell, and the nanocrystals within light up like a Christmas tree in red or green arrays of dots. These, in turn, can easily be spotted using an optical microscope and used to map out particle distributions within a cell, yielding information impossible to obtain by other methods.

The method, known as single-molecule imaging, has been demonstrated using other nanoparticle types, but UCNPs are unique because of their uncommon brightness and stability, and because they are powered by infrared light. This is both good for the studied cells, because infrared light is less damaging than visible or X-ray frequencies, and good for the people measuring them, because it can probe more deeply into tissue than other types of light. In fact, one prospect for future research is the imaging of entire animals.

Reflecting on the research effort's long-term goals, Cohen commented that cross-disciplinary sharing of ideas is crucial. "In general, we'd like to bring nanoscience to the larger scientific community, especially biology, where few researchers have had much exposure to it," he said. "Our goal is to make interesting and useful new materials that will let them do all sorts of experiments that would otherwise be impossible."

Are you using Twitter or other social media as a way to promote progressive causes like energy efficiency? What do you think about mandatory home energy audits or line drying clothes versus machine drying? Source image: Tina KellerSomebody close to me recently turned 50. Okay, it was me who just turned 50. My how things have changed since 1959! My first experience with computers was as a freshman lining up to hand over my punch cards to the computer operator to be fed into a computer that filled a room. Up until recently I got my news of the world through newspapers and television. For most of my life I stayed in touch with distant family and friends through letters and phone calls. When my brother was in Vietnam during the war we had to call him through short wave radio to tell him that his Corvette got smashed. (He didn't care. He was relieved that we were all okay.)

Now I get my information mostly off the Internet and through Twitter, the social media service that is in the news because of its use by the opposition parties in Iran. Twitter is like snail mail cubed. You send messages from your computer or smart phone that immediately show up on the computers or phones of all your "followers." You get followers generally by following others. It's kind of an unwritten rule that if someone is following you should return the favor. So far I am following about 30 people or groups and have 11 followers. But I just started.

I am following Energy Circle, a new Internet resource that is using social media to report news about home energy efficiency on Twitter. A recent "tweet" connected me to an article by Peggy in Toronto who thinks that mandatory home inspections should be replaced with mandatory energy audits upon the time of sale of a home. Advanced Energy's Research Director Melissa Malkin-Weber, tweeted "Energy saving smugness nixes scratchiness of air dried sheets. But don't ask my kids about how those stiff cloth diapers felt."

I agree with Peggie and Melissa. But what do you think about mandatory home energy audits or line drying clothes versus machine drying? Are you using social media as a way to promote progressive causes like energy efficiency? You can respond below, and your response needn't be limited, like "tweets" are, to 140 characters. Or sign up for a Twitter account and join the conversation at KQED Science!

Artist's depiction of a megalodon chasing two blue whales (image credit: Karen Carr, the Virginia Museum of Natural History)
Often I am drawn back to one place at the California Academy of Sciences, staring down at the dancing forms in the Lagoon's shallow water. Rays and sharks glide easily just above the tropical sand. Eventually, I see the lagoon’s shyer inhabitant, the guitarfish, whose body markings and shape resemble an upside down guitar. Sharks, ray, and guitarfish all belong to the subclass Elasmobranchii within the cartilaginous fish class Chondrichthyes. The Elasmobranchii also includes the infamous megalodon, thought to be the largest carnivorous fish ever to have existed. The megalodon was famed to reach lengths between 45 and 90 feet, dwarfing even today's most fearsome Great Whites.

What I find most interesting about this subclass is the body make-up these creatures share. They do not have a bony skeleton like humans; their skeleton is made up of cartilage—a dense connective tissue that is tough yet elastic. Their grace, speed, and great success as predators come from the fluidity of their movement.

This also makes it difficult for Ichthyologists to agree on taxonomy within this class as fossilized remains of cartilaginous fish are often poor. The oldest fossil on record of a megalodon, 18 million years old, is the only bone in the skeleton: a tooth. From the tooth, several researchers have tried to reconstruct the jaw and piece together what the body would look like. The tooth also suggests what this massive prehistoric shark preyed upon: There are bite marks on whales, dolphins, porpoises and sea turtles.

As the sharks, rays, and guitarfish pass by in the lagoon, I imagine the shadow of their giant cousin, the megalodon.

Which is worse for you, a can of tuna or a broken CFL bulb? Sorry, Charlie… image by Dave LifsonA paper expected to be published in the August issue of the lighting industry journal, LD+A, may quiet some of the controversy over the dangers of mercury in compact fluorescent lights (CFL). I’ve argued in this blog that the cut in mercury emissions from power plants due to the electricity saved when traditional incandescent bulbs are replaced with CFLs, greatly outweighs the amount of mercury that could escape from broken CFLs, plus what is emitted during the making and transportation of CFLs. But the paper, by Robert Clear, Francis Rubinstein, and Jack Howells, who do research at Lawrence Berkeley National Laboratory (LBNL), goes a step farther by showing that even a person who breaks a lamp is more at risk from mercury in the environment than from the mercury in the lamp itself.

The researchers point out that there is a distinction between the kind of mercury that you are exposed to from broken CFLs—elemental mercury—and the mercury emitted from power plant smokestacks after it finds it’s way into waterways and oceans, where it becomes methyl mercury. Methyl mercury accumulates all up the food chain, so that large fish like tuna can contain a lot of it. Methyl mercury crosses the blood-brain barrier and passes through a pregnant woman’s placenta to her fetus. Methyl mercury is responsible for developmental problems, while elemental mercury, which is inhaled, appears to be more of a hazard for adults and children, and only then in the case of severe or prolonged exposures. In most mild cases, when the elemental mercury exposure ends, the bad effects diminish and go away. This is unfortunately not true for the developmental problems caused by methyl mercury.

The startling conclusion of the paper is that in a worse case scenario—you break a CFL in a closed, unventilated room; you vacuum the carpet, throwing mercury into the air; you set the vacuum in a corner; and then sit in the room breathing for eight hours—the amount of mercury exposure is about equivalent to the exposure you’d get from eating a can of Albacore tuna.

Eating a can of tuna has positive health effects as well as the negative health effects from the mercury. There are no positive health effects from a broken CFL, and you can reduce your exposure. The researchers suggest that in the case of a broken CFL, you should immediately open a nearby window. You can limit contamination by gathering up the large pieces of the broken bulb into a bag and set the bag outside. The room should then be left to air out for an hour or so. If the lamp broke on a carpet you can vacuum, but it should be done quickly while the room is being ventilated, the vacuum cleaner should be removed to an outside area, and again the room should be left vacated for an hour or so. Once the vacuum cleaner has cooled, you can empty the contents of the vacuum cleaner bag into the bag with the broken bulb. Take the bag to your nearest recycling center.

The Farallones consist of a group of rocky islands that are 28 miles North of San Francisco Bay.A national wildlife refuge just outside the San Francisco Bay is now under surveillance! The California Academy of Sciences in partnership with U.S. Fish and Wildlife and PRBO Conservation Science has installed a web camera on the Farallon Islands.

The Northern Farallones were originally granted protection by President Teddy Roosevelt in 1909. However, these islands were not always protected. Human consumption decimated many populations, some never to return. The demand for fur, oil and meat devastated the elephant and fur seal population. By 1900, the robust Common Murre population dwindled down to a few thousand because of the demand for Murre eggs.

Today, the Islands are further protected under the Marine Life Protection Act and the Farallones are also deemed a state marine conservation area. The majority of visitors of the human persuasion are not allowed access to the islands as they would upset the balance of the largest seabird breeding colony in the United States. Those humans that do frequent the island include wildlife biologists and land managers who are conducting wildlife research.

PRBO Conversation Science has been a local on the island day and night conducting research and monitoring the natives. The webcam helps their cause by collecting scientific data from a remote location. The camera enables biologists to observe without disturbing wildlife or incurring adverse environmental impact.

The water surrounding the islands makes this an ideal stomping ground for marine life and seabirds alike. Coastal upwelling takes place in the spring around the islands. The Coriolis Effect along the coast drives surface waters away from the coast; this water is then replaced with the denser waters from below. Within the deeper waters is a wealth of nutrients that are photosynthesized into dense blooms of plant plankton when exposed to the sun. This energizes the marine food chain as the plant plankton is eaten by krill. Krill is then made available to eat for fish, birds, and marine mammals. It does not only feed surrounding wildlife but growing human populations as well. The most productive fisheries in the world are supported by coastal upwelling. Given the location and the diversity of wildlife, the Farallones is well worth protecting.

The webcam not only aids research; it assuages curiosity. Anyone can pilot the camera. A panoramic view of the island is set up for the user to navigate and explore. Field guides and information on the project are also given on the site to reference observations.

It will probably take more than a human FOXP2 gene to reach this future.Scientists have started to look at DNA to try to figure out why we can speak and other animals can't.  One gene that has caught their attention is called FOXP2.

People with a certain version of this gene have trouble forming words and speaking but are otherwise OK.  This is exactly what you would expect if a gene were primarily involved in speech.

One way to test this idea would be to put the human version of the gene into an animal and see what happens to that animal's speech.  A natural candidate would be the chimpanzee.  Humans and chimps are around 98.8% similar at the DNA level* and their FOXP2 gene has only two differences.

Unfortunately (or fortunately…), we can't yet do this experiment because we aren't very good at changing a chimp's genes.  But what we are good at is changing a mouse's gene.  And this is exactly what scientists did in a new study.

The scientists changed a mouse's FOXP2 gene into a human's.  Now no one expected that we'd have a Mickey Mouse on our hands.  Mice just don't have all the equipment for speech and it is really unlikely that the only difference between mice and people in terms of speech is this gene.

But by putting a human FOXP2 gene in mice, we can learn some things about how the gene influences human speech.  Does it change the vocalization part of the brain?  Does it change something with mouth anatomy?  Something with breathing?

The results with these mice were interesting.  They weren't suddenly chatty but changing the gene definitely caused the mice to emit different squeaks than their natural cousins.  The vocalization part of the mouse's brain also changed.

These results suggest that FOXP2 affects human speech at least partly through changes in the brain.  And that if you give a mouse a human Foxp2 gene, you change the way it communicates.

The next steps are a little harder to figure out.  We do know that Neanderthals had the same FOXP2 gene that we do.  Perhaps by comparing human, chimp and Neanderthal DNA we'll be able to find other genes involved in speech too.  We'll have to wait a few months for this kind of analysis as the Neanderthal genome isn't quite done yet.

*When we include extra copies of some DNA and missing DNA, the similarity goes down to 96%.

Here is a video discussing the results of the study.

Ain't love grand? Once courtship and mating are over, the female hornbill finds a tree hollow and seals herself in with dung, fruit and pellets of mud.

I love our hornbills. Situated in the Rainforest section of the Zoo, between our gibbons and our chimps, they are often overlooked, yet I find them fascinating.

The female has the bright blue gular pouch (an expandable throat sac, used for short-term storage of food) and the male has the pale yellow version.  Like all hornbills, they have a distinctively large and down-turned beak.  These Malayan Wreathed Hornbills are one of the 54 species found in Asia and Africa.

Their dramatic nesting ritual is what makes them so interesting. Once courtship and mating are over, the female finds a tree hollow and seals herself in with dung, fruit and pellets of mud. The male gathers the pellets from the forest floor and swallows them, later regurgitating small saliva-cased building materials. He then gives them to the female who stays inside the nest leaving a slit for a window big enough to receive food and materials. For the next 6-8 weeks the male feeds the female through this opening. She does not emerge until she has molted and re-grown fresh feathers and her young has grown and become feathered, as well. Then, both mother and child knock down the wall and appear on the scene, happy and healthy. Last year the public was enthralled, as our hornbills participated in this ritual.

The zoo is concerned with the status of hornbills in the wild, and since 2004, the Oakland Zoo Conservation Fund has worked with a fantastic program coordinated by the Hornbill Research Foundation. Besides collecting data, the foundation has launched a Hornbill Nest Adoption Program, which works to foster conservation of these beautiful birds. Illegal logging and the poaching of young birds for the pet trade are the key issues facing hornbills. The Nest Adoption Program employs local people to look after the hornbills in their nests and collect scientific data about them.

When you adopt a nest, you get a wonderful pamphlet of information about the hornbill, a map of the location of your particular nest, a profile of your guard and, my favorite, a break down of what food the male brought to the female (2 figs, .3 millipedes, 1 lizard).

This summer, eighteen Oakland Zoo teens and staff will embark on a journey to visit Thailand and will spend a day at Khao Yai National Park with the intention hope to spot birds, nests and learn first hand about the project.  They will also visit with the Young Bird Conservation Club, which creates Hornbill art to sell to zoos for their Conservation Projects. To prepare for their trip, these inspired have been attending workshops and raising funds to adopt two nests of their own.

Back at the zoo, the summer will be filled with more hornbill conservation action as ZooCamp 2009 has adopted the species as their official summer animal. With a hornbill on the front of their t-shirt and the Hornbill Research Foundation logo on the back, all campers will be learning about this animal and the project that supports them. Each camper has also contributed a bit of their camp fee into the program and will surely leave camp with the contribution of knowledge and compassion for these incredible birds.

Come by and visit our hornbills, join us this summer at ZooCamp ,or adopt a nest yourself (http://www.zoo.org/conservation/hornbill.html).

This past Friday, a few thousand folks attended Lawrence Livermore National Laboratory to see dignitaries including California Governor Arnold Schwarzenegger and U.S. Senator Dianne Feinstein dedicated the world's newest and most powerful laser, the National Ignition Facility (NIF).

Governor Schwarzenegger, clad in a pink tie– an odd sartorial choice for dedicating this giant hulk of a building housing 500 trillion watt laser housed within– nevertheless succeeded in channeling at least some of his Hollywood days. When they originally visited the facility last November, "we were so excited that we said, 'We'll be back.'"

The project's goal is to focus 192 laser beams onto a BB-sized capsule of hydrogen fuel in order to heat it to the point of ignition, that is, to achieve a nuclear fusion reaction where more energy comes out of the capsule than is put in. Fusion is the common process for creating energy in the Sun, and has been demonstrated on Earth both in the apocalyptic specter of thermonuclear weapons and in the more hope-inspiring form of plasma reactors such as those at the Joint European Torus (JET) in Britain. However, ignition has yet to be demonstrated, as JET requires a constant influx of energy greater than anything it is capable of producing. If all goes well within the next several months, ignition could be achieved at NIF as early as 2010.

For all of these exciting aspirations and promise of new technology, the press' reaction to NIF throughout the twelve years of its construction has been often lukewarm, and at worst scornful. Some of this has been deserved, and it is certainly true that the facility's $3.5 billion dollar construction cost is a hard price tag to swallow.

However, NIF is a worthy scientific cause and might well turn out to be an excellent investment. To put things a little bit into perspective, other large science projects are similarly expensive. The Large Hadron Collider (LHC) at CERN and the Hubble Space Telescope have both been estimated at about $6 billion. Dianne Feinstein argued in the past (and reminded the audience at Friday's dedication) that Enron needlessly cost $9 billion during the California Energy Crisis. Put another way, with $9 billion you could (a) experience rolling blackouts while Enron power traders cheer for wildfires ravaging your countryside, or (b) assemble the world's most powerful laser and use it to bring the nation to the brink of being able to replicate, in a controlled manner, the sorts of reactions that power the Sun. Twice.

The physics promise of the NIF, meanwhile, is truly fascinating on all three fronts of NIF's stated goals: energy production, basic research, and national security.

Fission reactors, which extract atomic energy from the splitting of large atoms such as uranium, have been a viable source of energy since 1954. However, the waste they produce remains radioactive for thousands of years. Potential fusion plants, on the other hand, would operate by an altogether different mechanism: the merging of much smaller hydrogen atoms. Radioactive byproducts are still generated, but the timescale for their radioactivity is shorter, on the order of 10 to 20 years.

A significant line of inquiry has already been pursued toward commercially viable nuclear fusion at JET and its planned successor, ITER. Such experiments employ powerful magnetic fields to maintain hydrogen plasma in a confined space and heat it to the point of fusion as it soars around inside a doughnut-shaped ring.

NIF serves as a valuable compliment to these magnetic confinement experiments. Instead of forcing a fusion reaction to perpetuate using costly magnetic fields, the NIF laser will attempt to blast its fuel with so much energy in such a short time period that the fuel will have no time to expand before it undergoes fusion. "If it works, developments at NIF would entirely reshape the dialogue on nuclear fusion energy," said Brian MacGowan, a NIF Program Director.

Even the most optimistic estimates place the viability of these types of energy sources 20 years into the future. NIF itself will never be able to function as a power generator even if all experiments performed at the facility proceed exactly as planned. The raw potential for such power extraction is nevertheless tantalizing.

Additionally, there is basic research potential for NIF beyond fusion power. Stars are typically easy to observe from a distance but inevitably too far away and too inhospitable to explore up close. A miniaturized version of the reaction as created in the NIF target bay could provide an interesting model system. There is no way to tell, but it could be that hand in hand with this ability comes a better understanding of some of the deepest outstanding questions in physics as well, such as the nature of dark energy and dark matter.

NIF also offers a unique way for the U.S. to test the effects of nuclear weapons without violating the Comprehensive Nuclear Test Ban Treaty. NNSA Administrator Tom D'Agostino noted at the dedication that, particularly as the United States' nuclear arsenal ages, this will provide the U.S. with invaluable data.

We may emerge from this economic crisis a poorer, humbler country. Still, I hope that we are not yet so humble that we have lost the ability to dream big, and not yet so poor that we can no longer actively pursue at least a few of those dreams.