White House Honors Two Techies for Making Programming Cool

Bay Area residents Carlos Bueno and Kimberly Bryant are helping to prepare kids to use programming concepts in daily life and work.

Tech Titans Join Forces on Internet Surveillance

More than 60 technology firms and other groups are urging the federal government to let companies disclose Patriot Act data requests.

Crashes Cast Doubt on Future of Commercial Space Industry

Two recent crashes, including a fatal one involving a Virgin Galactic shuttle, raise new questions about the future of the commercial space industry. Twenty people who had purchased seats to fly to the edge of space on Virgin Galactic have reportedly asked for their money back. The second crash, with a company that carries cargo to space for NASA, happened late last month. We'll discuss the state of the $300 billion global space economy.

Novelist and Programmer Vikram Chandra Sees the Beauty in Code

Computer code has changed the world. But is it beautiful? That's the question at the heart of Vikram Chandra's first non-fiction book, "Geek Sublime." Best known as a novelist and UC Berkeley English professor, Chandra is also a computer programmer. We'll talk with him about the links between literary theory, aesthetics and the craft of writing code.

PBS NewsHour

8 things you didn’t know about manatees

         by Ruth Tam

November is Manatee Awareness Month. Celebrate by learning eight facts about the gentle sea cows. Illustrations by Ruth Tam

Manatees are the slow, lumbering, gentle giants of the aquatic ecosystem. Every November, the West Indian manatee, native to the Gulf of Mexico and Caribbean Sea, makes its way to Florida’s warmer waters for the winter.

The U.S.’s manatees are an endangered species floating close to extinction. Prior to 2010, there were steady gains in population over the years. Then, in 2010, a devastating number of more than 700 died. In 2013, the population winnowed down again, as 830 manatees died. With a population around 5,000, that’s nearly 20 percent of the entire species, wiped out in a single year.

In 1979, then-Florida Governor Bob Graham designated November as Manatee Awareness Month. Every governor of the state since has renewed the proclamation.

1. Manatees can swim as far north as Cape Cod.

While most manatees spend the summer months in the Gulf of Mexico, some vacation all the way up in Cape Cod waters.

In 2009, Florida Fish and Wildlife Conservation Commission’s manatee rescue coordinator Andy Garrett airlifted a manatee from the Jersey Shore down to Florida’s warmer waters. With water temperatures dropping, the scientists worried that the manatee wouldn’t make it far enough south to survive. Although manatees can swim up to 20 miles per hour in short bursts, their general speed is a slow putter at three to five miles an hour. “They move like a dolphin in slow motion,” said Patrick Rose, an aquatic biologist and executive director of the Save the Manatee Club.

         courtesy of Save The Manatee Club

Photo courtesy of Save The Manatee Club

2. They use power plant outflows to stay warm

As marine mammals, manatees need a temperate environment to survive through the winter. Despite weighing 1,000 pounds or more, manatees do not have a continuous layer of blubber like whales to stay warm. When aquatic temperatures drop below 68 degrees Fahrenheit, they seek higher temperatures.

In the past, manatees sought out warm water springs. Now, many rely on a more mechanical force for heated water: municipal and private power plants. The plants pump out warm water into surrounding canals or ponds, and up to 60 percent of manatees now spend their winters clustered around power plant outflows, Garrett said.

While power plants have extended the manatees’ range of wintering spots farther north, researchers worry about the impact if those plants go offline. Manatees usually return to the same spot every winter, and could return to an inactive power plant, only to die of cold in unheated waters. Human development has also blocked the entrance to some natural springs, making it difficult for them to reach other warm waters. Garrett said that spring renourishment projects are working to restore the natural flow of water, which would provide manatees wintering sites independent of humans.

         by Flickr user USFWS Endangered Species

A West Indian Manatee rests in the Crystal River National Wildlife Refuge on Florida’s gulf coast. Manatees Photo by USFWS Endangered Species

3. Alligators give manatees the right of way

In Florida’s aquatic highways, “even the big 12-foot alligator will give way to the manatee,” Rose said. What does this look like? If a manatee wants to get through, it swims up to gators in its way and bumps or nudges them to move.

Unfortunately, the same tactic doesn’t work with motorboats. Nearly 60 manatees have died this year alone after being hit by boats. Although 18 Florida counties have manatee protection zones prohibiting boat access or requiring sailors to slow down, watercraft collisions are still a threat to the manatee’s survival.

4. They grow new teeth their whole lives

Manatees spend six to eight hours a day eating sea grass and other aquatic vegetation. Their food has tiny granules of sand in it, which gradually wears down their teeth. Eventually, those teeth fall out.

But you won’t see any manatees sporting a gap-toothed smile. They constantly grow molars in the back corners of their mouth. As the front teeth grind down and eventually fall out, the molars fully emerge, pushing new teeth forward.

Manatees are also anatomically incapable of using their teeth to attack. “I’ve had to have my hand in a manatee’s mouth,” Rose said, “and you have to put your whole hand in before you reach the manatee’s teeth. They’re just not capable of any form of aggression.”

manatees25. Elephants are their closest relative

Let’s backtrack for a second. Manatees actually have enough unique evolutionary adaptations to be classified in their own order, sirenia. This classification includes one species of dugong and the three species of manatees: West Indian, African and Amazonian. The West Indian manatee lives in the United States.

But on land, the manatee’s closest living relative is the elephant. Manatees have three or four tiny nails at the end of each flipper, similar to an elephant’s toenails. They also have prehensile upper lips, a very shrunken version of an elephant’s trunk, that they use their lips to grasp and pull food into their mouths.

“It’s like two little hands in the upper lip on each side,” Rose said.

6. Speaking of relatives, the now-extinct Steller’s sea cow was the size of a small whale

The Steller’s sea cow was discovered by humans on the Commander Islands in the Bering Sea in 1741. By 1786, only 27 years later, the fur hunters living in the frozen north Pacific had hunted the sea cow to extinction. This species was part of the dugong family. They could grow up to 30 feet long, about the size of a small whale. Unlike their modern relatives, they had no teeth at all and feasted on kelp. They also could survive in cold water, which is deadly to the modern manatee.

Howard University professor Daryl P. Domning recently discovered Steller’s sea cow fossils in the sand of St. Lawrence Island. More than 30 species of sea cows have been discovered since 1977; half of those species were discovered and named by Domning and his team.

“We’re really living in a golden age of discovery of marine mammals,” Domning said. “Every year, strange new creatures are dug up.”

7. Manatees regulate their buoyancy with their lungs

Manatees’ lungs run along their spines on the top of their body. Their lungs are “like a flotation tank running along the backside of the animal,” Domning said. Using their rib cage muscles, they can compress their lung volume and make their bodies more dense.

They use this mechanism to come to the surface to breathe instead of actively swimming up and down. Even while they sleep, their rib cage muscles will relax, expanding their lung volume and gently carrying them to the surface. After they breathe, the muscles contract and the manatee effortlessly sinks back under water.

8. Humans are the biggest threat to their survival

Manatees have no natural predators or enemies. Humans can injure or kill manatees with their boats. Humans have also degraded their habitat by blocking natural springs and building up the coastline. People have also accelerated sea grass loss — now, both manatees and the environment they live in are classified as endangered.

“They’re the most docile, defenseless creature there is,” Rose said. “Man is the only real enemy the manatees have ever had. So now it’s up to us to literally save them from ourselves.”

Can’t get enough manatee? Tune in to a manatee livestream.

The post 8 things you didn’t know about manatees appeared first on PBS NewsHour.

How a global network of telescopes may give us first glimpse of a black hole


Watch Video | Listen to the Audio

GWEN IFILL: Now: an amazing scientific search pushing the limits of what we know about the cosmos, the quest to see a black hole.

The “NewsHour”‘s Rebecca Jacobson went to Chile for this report.

SHEP DOELEMAN, Principal investigator, Event Horizon Telescope: Black holes are some of the most exotic objects in the universe. They come about when matter gravitationally collapses in on itself, and everything becomes pulverized and crushed down into a single point.

REBECCA JACOBSON: MIT astronomer Shep Doeleman is leading an international effort to understand black holes. These exotic objects are fundamental to our understanding of the universe. When stars, dust, and planets cross the event horizon surrounding the black hole, nothing, not even light, can escape. But no one has ever seen one.

Doeleman is trying to change that.

SHEP DOELEMAN: The Event Horizon Telescope project is really about seeing what we have always thought as unseeable.

REBECCA JACOBSON: But to boldly go where no telescope has gone before, scientists have to drive up a 16,500 foot-high mountain. This is the Atacama Large Millimeter, or ALMA, in Northern Chile. ALMA’s 66 antennas form the most powerful radio telescope in the world.

Each antenna weighs 100 tons, and they are so accurate, they can see a golf ball nine miles away. They will form the anchor for the Event Horizon Telescope, a worldwide network of observatories that will capture an image of a black hole for the first time.

ALMA’s antennas sit just 400 feet lower in elevation than Mount Everest’s North Base Camp. Before going up the mountain, we had to undergo rigorous physical testing, because working at this altitude is dangerous.

My blood pressure was a little too high, so we waited a few minutes to see if it would go down.

Ivan Lopez is the safety manager at ALMA.

IVAN LOPEZ, Atacama Large Millimeter/submillimeter Array: If you don’t get to the minimum levels that we have for pressure and oxygen content in your blood, you’re not allowed to go up to the high site.

REBECCA JACOBSON: What could happen to you if you did go to the high site and your blood pressure was too high?

IVAN LOPEZ: You can get a stroke.

REBECCA JACOBSON: And too little blood oxygen can swell the brain and cloud thinking. Oxygen tanks help scientists battle nausea, dizziness and fatigue, but it can still be hard to think straight.

SHEP DOELEMAN: We have what we call summit moments. And what I can tell you is that, once, I spent about five minutes trying to screw in a screw, when, in reality, I was unscrewing it.

REBECCA JACOBSON: And it’s not just the altitude that makes working here difficult. The Atacama is the world’s driest desert. Trucks haul thousands of gallons of water to the observatory every day. Add to that high winds, hot sun, and dangers below ground.

DAVID RABANUS, Atacama Large Millimeter/submillimeter Array: We have actually designed the ALMA antennas to withstand an earthquake of grade nine.

REBECCA JACOBSON: But the tradeoff is worth it. Some say it’s the most beautiful view on Earth of the night sky.

Richard Simon is an astronomer working at ALMA.

RICHARD SIMON, National Radio Astronomy Observatory: The reason ALMA exists is that there is something about astronomy, about learning about our universe and reaching out into it that’s a very human and a very important thing to do.

REBECCA JACOBSON: In 1916, Albert Einstein’s theory of general relativity first predicted the existence of black holes. That was nearly 100 years ago, and that theory has not been disproven. But with no real visuals, it hasn’t been confirmed yet either.

This year, a cloud of space dust is spiraling into the supermassive black hole at the center of our galaxy. If it swallows that dust, as astronomers predict, the event horizon should light up, casting a shadow.

SHEP DOELEMAN: First question is, do black holes exist? And if we see the shadow, that will be the most powerful evidence we have that they do exist. I hope we will see something transformative. I hope we’re going to see something that knocks our socks off, but whatever we see, it’s going to be new and it’s going to raise probably more questions than we have answers to.

REBECCA JACOBSON: It’s a rare opportunity to find out if Einstein was right.

RICHARD SIMON: We think we know the theory of black holes. This is a key test. It’s the — one of the only black holes that we can actually observe and make direct measurements of.

It needs telescopes spread all across the globe to get the maximum separation between telescopes and the maximum resolution, the finest picture possible.

REBECCA JACOBSON: Even ALMA’s powerful antennas can’t do it alone. ALMA will be the anchor for a worldwide network of telescopes. Scientists will link ALMA’s antennas with telescopes in Hawaii, California, Mexico, Arizona, Spain and the South Pole, and then piece together all of the information they collect.

Synching all these telescopes means equipping each with the most precise atomic clock available. That means taking out ALMA’s clock, and replacing it with one that costs a quarter-of-a-million dollars that won’t lose a second in the next hundred million years.

SHEP DOELEMAN: So, right now, we’re in the holiest of holies, the central reference room for all of ALMA. And these are where all the signals that are sent to all the antennas originate. What we have basically done is perform a heart transplant for ALMA.

REBECCA JACOBSON: The Event Horizon project is estimated to cost between $10 million and $20 million over the course of 10 years. But Simon says its mission, and ALMA’s, is worth more.

RICHARD SIMON: There is a deep curiosity that we all have. A hundred years from now, my name and what I have done for this project will probably not be remembered, but what this instrument does and what it means to everyone around the world is something that will be remembered.

REBECCA JACOBSON: The Event Horizon Telescope is slated to begin observations in the spring.

For the “PBS NewsHour,” I’m Rebecca Jacobson in the Atacama Desert in Chile.




The post How a global network of telescopes may give us first glimpse of a black hole appeared first on PBS NewsHour.

How seeing a black hole’s shadow will tell us if Einstein was right

To capture the first-ever image of a black hole, a team of international scientists travel to extreme altitudes in Northern Chile’s Atacama desert, home to the world’s best view of the night sky. Watch PBS NewsHour’s full story on the ALMA observatory.

In a control room atop a 16,500-foot mountain in Chile’s Atacama desert, Shep Doeleman and his international team of scientists are pulling the “heart” out of a $1.4 billion telescope. They are removing the atomic clock that the telescope relies on to read signals from space, and replacing it with a better one, one that won’t lose a second for the next hundred million years.

“Basically what we’ve done is perform a heart transplant for ALMA,” said Doeleman, an astronomer at MIT and the Harvard-Smithsonian Center for Astrophysics.


It’s a delicate operation. Scientists wear oxygen tanks so they don’t pass out from the altitude. Special housing protects the atomic clock from Chile’s violent earthquakes. Doeleman and his team won’t open the casing to show us the clock, especially while they’re running tests. It is too sensitive, and they don’t want to risk jarring it.

Doeleman holds a device in his hands that they are using to test the new clock. It’s a clock too, but it looks more like a bomb — which made getting through airport security from the U.S. to Chile tricky, he said.

If their operation is successful, the most powerful radio telescope in the world, the Atacama Large Millimeter/submillimeter Array, will join 11 international observatories capture the first-ever image of a black hole. PBS NewsHour recently traveled to Chile to meet some of the scientists behind this international collaboration.

ALMA's Operations Support Facility at night, just as most astronomers are getting to work. Photo by Joshua Barajas/PBS

ALMA’s Operations Support Facility at night, just as most astronomers are getting to work. Photo by Joshua Barajas/PBS NewsHour

When we arrived at ALMA’s low site — at 9,500 feet above sea level — Richard Simon met us in the control room there. He was the astronomer-on-duty at ALMA that week from the National Radio Astronomy Observatory. He towers over the other scientists and engineers; at 6’10” tall, he may be the world’s tallest astronomer, he joked. At 9 a.m., the control room was fairly empty — just two people tapping away at the circle of computers. Unfinished puzzles were strewn across a table. Above, monitors showed the antennas at the high site.

In the middle of the night when ALMA takes most of its observations, this room is filled with scientists from all over the world, he said. ALMA is run by a conglomeration of radio astronomy organizations from Europe, Canada, Japan, Chile and the U.S.

Simon rubbed his eyes. He’d been awake for more than 18 hours, and just finished his overnight shift. Earlier that morning, Jupiter and Venus had passed each other in the sky. The image ALMA scientists captured looked as if Jupiter and Venus were flashing a “thumbs up”. They printed the image and tacked it up in the control room, on a white board atop shift schedules and notes.

How does it feel working 16,500 feet above sea level? Scientists at the ALMA observatory in Chile report.

It’s images like that which make dealing with high altitude sickness, long shifts, nausea and the driest desert in the world worth it, Simon said. And the prospect of seeing a black hole is key to ALMA’S existence.

“We are reaching out to the universe to study these mysteries,” Simon said. “The black hole at the center of our galaxy is something that wasn’t even imagined a few decades ago.”

Black holes are voracious eaters that swallow everything they can — dust clouds, stars, planets and other space debris — and they’re surrounded by what’s known as an event horizon, the area where the gravitational pull is so strong that nothing — not even light — can escape.

Jupiter gave ALMA scientists' a "thumbs up" as it passed Venus on August 18th. Photo by Joshua Barajas/PBS

Jupiter gave ALMA scientists’ a “thumbs up” as it passed Venus on August 18th. Photo by Joshua Barajas/PBS NewsHour

“Black holes are some of the most exotic objects in the universe,” Doeleman said. “They come about when matter gravitationally collapses in on itself, when the atomic forces that normally hold, let’s say, a rock into its shape are overcome by gravity and everything becomes pulverized and crushed down into a single point.”

Einstein’s theory of general relativity predicted the existence of black holes in 1916, and to date, they’re the best explanation we have for many phenomena in our universe, Doeleman said.

But how do you see something that is, by definition, unseeable?

Other instruments have been able to observe and measure the effects of a black hole on stars, planets and light, but no one has ever actually seen a black hole, said David Rabanus, instruments manager for ALMA.

“There is no telescope available which can resolve such a small radius,” he said. “It’s a very high-mass black hole, but that mass is concentrated in a very, very small region.”

MIT astronomer Shep Doeleman explains how the Event Horizon Telescope works.

Without an image of one, no one has been able to confirm that black holes even exist, Doeleman says.

This Earth-sized telescope is science’s best hope of seeing one, Doeleman said. And it relies on a technique called very long baseline interferometry, or VLBI.

VLBI works in the same way that ALMA’s 66 antennas combine to make one telescope, only on a much larger scale, Simon said. The antennas are spread out across a wide area. As radiation from space hits the antennas, the data is sent to the correlator, ALMA’s “brain”, which pieces the information together to make an image. ALMA’s atomic clock measures exactly when the waves of radiation hit the receivers.

ALMA’s antennas are the most precise and sensitive in the world. Keeping them working means cooling the receivers to 3 or 4 degrees Kelvin, or almost absolute zero, Rabanus said. A blue drum called a cryostat nests inside each 100-ton antenna, chilling the receivers to the point where they can see the coldest objects deep in space.

“Cold clouds, cold gases, which are maybe 20 Kelvin only…We have to be colder than that in order to receive it. If we were warmer than those we would actually send out that radiation,” Rabanus said.

The receivers aren’t the only highly sensitive equipment. Each antenna’s dish needs a very specific surface texture to pick up minute radiation waves from space. The roughness of the surface needs to be accurate to within 50 microns, or the width of a human hair, Rabanus said.

In the lab at ALMA, engineers work on testing and maintain cryostats, the big blue drums that keep the receivers at 3
         or 4 degrees Kelvin -- cold enough to receive faint radiation from space. Photo by Rebecca Jacobson/PBS NewsHour

In the lab at ALMA, engineers work on testing and maintain cryostats, the big blue drums that keep the receivers at 3 or 4 degrees Kelvin — cold enough to receive faint radiation from space. Photo by Rebecca Jacobson/PBS NewsHour

Those antennas are what will boost the Event Horizon Telescope’s sensitivity by a factor of ten, Doeleman said. Still, the observatory can’t do it alone.

To get a wide enough “lens” with a high enough resolution to see a tiny black hole, the Event Horizon Telescope connects observatories around the world — from Chile, to Mexico, Hawaii, California, Spain and all the way to the South Pole. To sync all these observatories up, every telescope needs to use the same atomic clock — hence ALMA’s surgery.

Together, they will act as a single telescope, peering 152,844,259,702,773,820 miles past stars and planets, through gas clouds and dust to catch a picture of Sagittarius A*, the supermassive black hole at the center of our galaxy.

There, a cloud of space dust, simply called G2, is circling the black hole. If it falls in, the edge of that black hole — called the event horizon — will light up, the brightest it has been in 100 years. The black hole will cast a shadow against that flare.

“Einstein’s equations tell you exactly what the size and shape of that shadow should be, so if we could image a shadow we’d be able to test Einstein’s theories in the one place where they might really break down — at the edge of a black hole,” Doeleman said.

Dimitrios Psaltis, a theoretical physicist at the University of Arizona, admits he’s hoping to see something unexpected emerge from the data.

“This is the horse we’re betting on,” Psaltis said. “Most people go into fundamental research not because it’s exciting being on a computer 18 hours a day. We do it in hope that we hit gold and make a fundamental discovery that will be remembered. This project has that chance.”

If the shape of the shadow doesn’t match Einstein’s equations, it will be a transformative time for physics, Psaltis said. It will give the field a chance to move forward.

And if it matches, and Einstein’s theory of general relativity is confirmed?

“That would tell us that Einstein was on the right track, that all methods that rely on general relativity are sound,” Doeleman said. “It would be a wonderful confirmation of one of the most beautiful theories that’s ever come out of physics.”

The post How seeing a black hole’s shadow will tell us if Einstein was right appeared first on PBS NewsHour.

How soil and squirrels offer cues on Alaska climate change


Watch Video | Listen to the Audio

GWEN IFILL: Now the second of two field reports from Alaska on the impact of climate change and warmer temperatures.

Science correspondent Miles O’Brien reports from the 49th state on how those changes are affecting greenhouse gas levels and the consequences for the local ecosystem.

MILES O’BRIEN: To get to the root of global warming in the Arctic, scientists need to pull out some serious tools.

WOMAN: On three. Yes.


MILES O’BRIEN: But that doesn’t mean they have to take themselves too seriously.

Near Alaska’s Toolik Field Station, caught up with a pair of researchers on a backbreaking mission to drill cores in soil frozen hard as concrete.

MEGAN MACHMULLER, Colorado State University: It’s hard work, especially hard to pull up frozen soil.

It’s something that we’re very passionate about because, you know, it’s so critical to understand the functions that are beneath our feet. And so that motivates us, and we have fun while we’re doing it.

WOMAN: You think about here? OK. Here we go.

MILES O’BRIEN: Megan Machmuller is a postdoctoral fellow and Laurel Lynch a grad student at Colorado State University. They’re part of a team trying to understand how and when the huge store of carbon, methane and other greenhouse gases permanently frozen in the Arctic tundra might be released into the atmosphere.

LAUREL LYNCH, Colorado State University: Right now, our current estimates are that the Arctic stores more carbon in this landscape than is currently held in our entire atmosphere.

MILES O’BRIEN: Just mention the word tundra, and you probably think of a barren, lifeless landscape. And looking across the horizon here, you might think, well, that is, in fact, the case. But on closer inspection, this place is just brimming with life.

The plant life is vibrant and diverse, and the soil is rich with chemical compounds and thousands of kinds of organisms.

Soil ecologist Matt Wallenstein is the leader of this team.

MATTHEW WALLENSTEIN, Colorado State University: Since the Ice Age, the plants have been taking carbon out of the atmosphere and storing it in the soil. So this has essentially been depositing carbon from the atmosphere into this vault.

MILES O’BRIEN: And here in the Arctic, the climate is warming twice as fast as the rest of the world. As things heat up, microbes thaw out. They start feeding on the soil, expelling carbon dioxide.

MEGAN MACHMULLER: Now, when it’s colder, activity is limited. The Arctic, of course, as we know is warming at an unprecedented rate. So it’s going to be a very unique situation for this ecosystem. Under warmer conditions, we may see a release of carbon back into the atmosphere.

LAUREL LYNCH: It’s easy to feel that you live a few thousand miles from the Arctic and that you’re safe, but we’re not because, as we’re finding out more and more, our atmosphere is connected, and we are all kind of in this together.

MILES O’BRIEN: To find out how much carbon the microbes might release, the team ships the cores back to their lab in Colorado, where they determine the chemistry and composition of the soil, and they extract DNA from the microbes in order to identify them. The data they gather will be incorporated in computer climate models that aim to predict where we are headed.

Do you have a sense, or is the data just not in yet, that we’re near this kind of a tipping point?

MATTHEW WALLENSTEIN: The data is not in yet. If we do indeed reach those tipping points, the consequences would be really dramatic and there would not be anything we can do about it. So it’s really important that we think about what we can do now, while there’s still time to act.

MILES O’BRIEN: Here on the tundra, another team is focused a little higher on the food change, on an animal whose sleep and hibernation patterns take subtle cues that are related to the climate. They are Arctic ground squirrels.

During our visit in May, the sun never set in this beautiful valley. And you might guess the squirrels would take advantage of all that extra daylight to forage and fatten up for the long, dark, cold winter. But it turns out they don’t. The squirrels stick to a rigid schedule. On sunny days, they are out of their burrows by 9:00, back underground by 7:00, like clockwork.

This begs an important question for physiological ecologist Cory Williams.

CORY WILLIAMS, University of Alaska Anchorage: So, the questions we have are, what is the function of maintaining circadian rhythms in an environment that never becomes dark, and what are the cues these animals use to keep their rhythms entrained in a natural environment, in the absence of a light-dark cycle?

MILES O’BRIEN: Williams is a postdoctoral fellow at the University of Alaska in Anchorage. He and his friends had their hands full at Toolik capturing, gassing, drawing blood, and gathering data from body temperature loggers and light-sensitive collars worn by the squirrels they are studying.

CORY WILLIAMS: And these light collars provide us information on when they’re above ground and when they’re below ground.

MAN: OK, girl.

CORY WILLIAMS: And the body temperature provides us information on the circadian body temperature rhythms that they have.

MILES O’BRIEN: He says the squirrels get cues from subtle fluctuations in the light intensity and the temperature, and he is testing their ability to adjust by time-shifting, essentially giving them jet lag, and then returning them to the valley.

The squirrels also have a very strong circannual clock, which dictates when they start hibernating, like this little guy, and when they wake up in the spring.

CORY WILLIAMS: We want to understand how much plasticity they have in terms of being able to adjust their annual timing based on spring snowfall. And we want to know whether this is going to change over time in response to climate change.

MILES O’BRIEN: Will warmer temperatures cause them to wake sooner? And then could the added precipitation in the form of late-season snowfalls, predicted with climate change, make it hard for them to forage for food?

The questions are hard enough to answer for the squirrels alone, but, of course, they are just one piece in a big, complicated puzzle.

CORY WILLIAMS: I think one of the difficulties with a species like the Arctic ground squirrel is that they’re on the food chain for a large number of animals. So wolves feed on them, foxes feed on them, raptors feed on them. Owls will feed on them.

And so in order to make predictions about what’s going to happen to the species, you have to understand what’s going to happen to all of the predators in the system as well.

MILES O’BRIEN: The system is intricately connected by causes and effects. The Trans-Alaska oil pipeline that passes through here offers a reminder that human beings are more than just observers of the changes. We have done much to dig the hole.

Miles O’Brien, for “PBS NewsHour,” Toolik, Alaska.

The post How soil and squirrels offer cues on Alaska climate change appeared first on PBS NewsHour.