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Science

  • A Cosmic Adventure

    More than 20 years ago Comet Hyakutake graced the skies of Earth, passing closer than any other comet had passed in 200 years. It was a spectacular sight, made even better because it appeared to pass through the handle of the Big Dipper. This photo, taken by Glen Gould and stitched together by me, is the result of quest that took persistence and creativity.

    Seattle is not a very reliable place to see stellar events and March 1996 was typically cloudy. We knew we had to travel somewhere to photograph the comet. But where? Many of our usual viewing sites in eastern Washington were covered in snow, so we decided to head to Othello. To our surprise, there was as much light pollution in this sparsely populated area as in a big city. Each small farm had two to three unshielded mercury vapor lights perched on tall poles. Light lessens the ability to see the stars and makes it impossible to capture a comet on film. 

    Defeated, we spent the night in a hotel and set off to eastern Oregon the next morning, hoping that the rain shadow of Mt. Hood would be clear and dark. That night we found a small spot by a river to pitch our tent. Soon after, light clouds started to gather but our hope did not wane. We set an hourly alarm so we could jump out of the tent and assess the sky throughout the night. No luck. By the morning snow started falling. Disappointed, we headed back to Seattle.

    After arriving home around 2:00 PM, we decided to look at the national weather map to find a place with clear skies. We chose Las Vegas. That might sound strange given the vast amount of light pollution, but we know the area outside Las Vegas well. The desert is deserted and there are enough mountains around that is it possible to mask the glow of Las Vegas lights. Besides, there are not many places where there are frequent flights and seats available on short notice. We packed up the camera equipment and headed to the airport.

    At the ticket counter we explained our desperate need to get to Las Vegas. The agent assumed we were eloping, took pity, and got us the last two seats on the plane. Fortunately all this happened in the pre 9-11 days, as the apparatus needed to photograph the comet would never have gotten through security. 

    Photographing stars and comets requires a long exposure. The Earth is constantly rotating, so it is necessary to compensate by using a device called a star tracker. The tracker moves the camera to match the rotation of the Earth. The photo will then capture stars as pinpoints and not as smears of light. 

    We didn’t have the money to buy a motorized star tracker, so Glen built a manual one. He used a very large barn door hinge, a paint stick, a small LED clock, the numbered part of a mechanical kitchen timer, a small battery-operated gooseneck lamp with a red filter, a straw, and some assorted screws. The camera gets mounted on the hinge. The paint stick becomes a crank. The numbers on the timer guide the manual turning of the crank. The turning rate is monitored using the LED stopwatch and the lamp. Turning the crank causes the hinge to open, thus changing the angle of the camera. With a steady hand, it is possible to match the rotational speed of the Earth. (Build your own, see these instructions.)

    We arrived in Las Vegas at 10 PM, rented a car, and drove north for an hour an a half. Then we pulled to the side of the road and set up the apparatus. Glen positioned himself on the ground in cranking position and I stayed on the lookout for the occasional car. Each exposure took up to 10 minutes. When I announced a car in the distance, Glen put a black card in front of the lens until the car passed. All the while he would continue to crank the apparatus. 

    It turned out to be an beautiful night and the end to an amazing cosmic adventure.

  • Seeing the Small: Eric Betzig at STARMUS 2016

    STARMUS 2016 featured many talks about the cosmos and using sophisticated instruments, like LIGOS, to peer backward in time. Just as fascinating was a talk by Eric Betzig, whose quest is to image the very small—that is, living cells. 

    A challenge for biologists is to see 3D images inside live cells and at the resolution of a molecule. There are many obstacles to this type of imaging, including something called the diffraction limit which restricts how close two things can be and still be imaged sharply. Another problem is that the amount of light needed to see small things results in phototoxicity—damage to the cells. Although it can be useful to look at dead cells, real insights will come from looking inside living cells and observing how they operate.

    Dr. Betzig found ways to get around the imaging obstacles. First with photo activated localization microscopy (PALM) and later with Lattice Light Sheet Microcopy and Structured Illumination Microscopy (SIM). 

    Brightly illuminating a cell causes the substructures to reflect light back such that the light from one substructure interferes with the one next to it. To get around this, Dr. Betzig found that he could build up an image by using a random process to illuminate small parts of the cell. If you do this enough times, you’ll eventually illuminate each part. No more interference. The image is sharp. This is essentially the PALM approach.

    His later approaches use more sophisticated techniques to illuminate cells and minimize the instantaneous power directed at a cell. This allows him to image living cells in stunning detail. He showed a movie of a lysosome in action inside a cell. Quite amazing. 

    Dr. Betzig won the nobel prize in 2014 for his early work. At STARMUS 2016 he said this was not his best work—as he feels his best is yet to come. I can’t wait to see what else he does!

    Take a look at:

    Imaging Life at High Spatiotemporal Resolution

     

  • Paleoastronomy: Why Fish Left the Sea

    At STARMUS 2016, Steve Balbus, Ph.D. (Theoretical Astrophysics) stepped outside of his main field of study—magneto rotational instability—to explain his theory of why fish grew legs and left the sea. He pointed to two main factors—geography and tides. 

    In the Devonian period (roughly 417 to 350 million years ago) the continents as we know them today did not exist. Back then there were only two continents, and they were moving towards each other. As they got closer, there was a narrow channel of water between them. That’s where the tide comes in. (Image: Map of the continents as they looked 370 million years ago. Licensed under the Creative Commons Attribution-Share Alike 4.0 International. Author: Colorado Plateau Geosystems, Inc.)

     

    Tides are caused by forces exerted on the Earth by the moon and the sun. High tides occur twice a day (as do low tides), but there are times when the high tide is highest. Tides are highest when the sun and moon align in a straight line. The scientific word for this is syzygy. This happens during a new moon and again during a full moon. The force of the sun reinforces the tidal force of the moon. (You can view a simulation of tides on the Science Rocks website provided by Everett Meredith Middle School.)

    In narrow channels, the effect of a tide is more dramatic. The highest high tide is even higher, flowing inland even farther. If you are a fish traveling with one of these high tides in a narrow channel, you have a chance of getting stranded in a tidal pool that’s far inland. Until there is another very high tide like the one that stranded you, you will be trapped. If this happens enough times, there is evolutionary pressure to do something about it. Upgrade your fins to legs!

    Sounds easy, but with anything evolutionary it takes a  l o n g  time. 

    Professor Balbus points out that the moon and sun have the same angullar radii. That means when you look into the sky, the sun and the moon look about equal in size. Of course we know they are not, but the fact their angualr radii are equal means their tidal forces are equal. When these two celestial bodies line up, the tidal force doubles. Trapping fish in tidal pools might not have happened if our moon had a smaller angular radius with respect to the sun. There were other other factors at play to encourage the evolution of tetrapods, but he makes a convincing argument for tides having a major role.

    For details, see:

    Dynamical, biological, and anthropic consequences of equal lunar and solar angular radii, 2014, Steven A.Balbus, Proceedings of the Royal Society. 

  • Adventures at the Ends of Chromosomes: Elizabeth Blackburn to Speak at STARMUS 2016

    At first glance, I thought Dr. Blackburn’s research was a bit esoteric. Telomerase? Telomere? What are these things and why should I care? Then I began digging into these terms and her work. I now care, perhaps you should too!

    Telomerase is an enzyme that elongates telomeres. Telomeres are repetitive sequences at the end of a chromosome that keep the ends from deteriorating. It’s not good for your chromosomes to unravel at the ends. If the ends are damaged, the chromosome can’t replicate properly. Your cells are going to die, and so will you. 

    Dr. Blackburn and Carol Greider discovered telomerase in 1984. How do you find something like that? They used  substances labeled with radioactivity to permeate the cells they were studying. The radioactive substances distributed themselves such that they were able to see patterns of telomerase activity—the telomerase enzyme reaction. Not to worry about the radioactive substances, you need to be careful with them, but they aren’t going to kill you unless you ingest them. The radioactivity creates an image on an emulsion that is similar to a photograph, but it is called an autoradiograph. It’s a technique used a lot in biological research. (Image under Creative Commons Attribution-Share Alike 4.0 International license, by Bengt Oberger.)

    As cool as this research seems, I was struggling to find how this particular discovery might impact my life. Then I found a paper with Dr. Blackburn as fifth author: Can meditation slow rate of cellular aging? Cognitive stress, mindfulness, and telomeres. That got my attention! If mindfulness meditation can slow my cells from aging, sign me up!

    Perhaps this excerpt will entice you to read the entire article:

    We review data linking telomere length to cognitive stress and stress arousal and present new data linking cognitive appraisal to telomere length. Given the pattern of associations revealed so far, we propose that some forms of meditation may have salutary effects on telomere length by reducing cognitive stress and stress arousal and increasing positive states of mind and hormonal factors that may promote telomere maintenance.“

    Dr. Blackburn is a great champion of science. In 2002 she was a member of the President’s Council on Bioethics. However, because she opposed the Bush Administration, she was taken off the council n 2004. 

    "There is a growing sense that scientific research—which, after all, is defined by the quest for truth—is being manipulated for political ends” ~ Elizabeth Blackburn

  • The Universe Waved and We Heard It

    More than 100 years ago Einstein predicted the existence of gravitational waves—ripples in spacetime, where space is stretched in one direction and compressed in the other. The prediction is a consequence of his theory of general relativity, fitting nicely with his mathematical model. It wasn’t until September 14, 2015 that anyone observed a gravitational wave. It’s not that the Earth hasn’t been hit by them. We haven’t had a way to detect them. Gravitational waves are very tiny. Really tiny. Like 1/1000 the diameter of a proton. To measure something like that, you need a very special instrument—an interferometer, and not just an off-the-shelf model. 

    The Laser Interferometer Gravitational-Wave Observatory (LIGO) is designed specifically to detect these waves. The project is a collaboration of many scientists, technicians, colleges, and universities. LIGO uses two interferometers, one located in Hanford, Washington and the other in Livingston, Louisiana. Each is identical, even in its orientation.  They are very large instruments, as you can see in these images (courtesy of LIGO CalTech). This is the Hanford site. The next image is the Livingston site.

    When a gravitational wave encounters the Earth, it will reach one of the locations first. This gives scientists clues to the origin of the wave. When the wave arrived on September 14, it was seen at both locations, but with a 7 millisecond difference—the time it took for the wave to travel from one location to the other. 

    The wave is so tiny that you might wonder if LIGO really detected a gravitational wave. They weren’t sure either, which is why they did not announce their finding until February 11, 2016. This gave scientists a chance to complete various verification protocols that gave the confidence of almost 100% that they did indeed observe a gravitational wave. 

    It is an extraordinary observation considering that footsteps, storms, traffic, ambient temperature, and just about anything else you can think of that causes motion can be detected by LIGO. It is an incredibly sensitive instrument. So sensitive, it can detect the motion of ocean waves during a storm. The scientists use a variety of techniques to tease out the signal of a gravitational wave from the noise of everything else. For example, to subtract out the ground vibrations contributed at each location, they place an array of 100 seismic detectors at each interferometer site. Using the seismic signals and machine learning techniques (statistics) scientists can figure out which vibrational “squiggles” are from the site and which are not. They have to use a different technique for each type of unwanted noise source. 

    What is actual signal like? It’s a short chirp. 

    This is relatively old news, so why am I writing about it? Barry Barish is speaking at STARMUS 2016 on “Einstein, Black Holes and a Cosmic Chirp.” I will be attending STARMUS and decided to find out what role Barry Barish had in the discovery.  

    The National Science Foundation first funded exploratory studies in 1980. By 1989 the project started in in full force, more or less.  An experiment of this magnitude requires a special person to run the project. It’s a big budget, with personnel and instruments spread over several locations. It’s cutting edge science. It had to be precisely executed. The people in charge, though extremely smart and well meaning, weren’t able to make sufficient progress. It wasn’t until Barry Barish was appointed laboratory director in 1994 that LIGO took off. One person can make a difference. I look forward to his talk.

  • Good Vibrations: Brian Greene and String Theory

    At STARMUS 2016 Brian Greene will tell us about String Theory and the Nature of Reality. He will do this in just 20 minutes. So I’ll try to explain it to you in just a few paragraphs but from the perspective of a non-physicist.

    String theory rose from the quest to explain inconsistencies in existing theories in physics. Gravity seems to be the bad boy that doesn’t fall in line with quantum physics and general relativity. If scientists could reconcile that, they might even have the holy grail—one theory that explains everything in the physical universe. 

    The idea of unifying explanations of the universe is laudable, but the “stringicists” have given rise to even more theories—strings, superstrings, supersymmetry, branes, m-branes, and more. They  generated so many types of string theories—Type 1, Type IIA, Type IIB, Type HO, Type HE, and so on—that they themselves had to devise a unified theory of string theory call M-Theory (the mother of all string theories). 

    So what’s it all about? Strings are tiny, one-dimensional vibrating entities. The vibrational state of the string manifests itself as different physical particles. We don’t see a string, but we can observe ordinary particles and measure the particle’s mass and charge. But under the hood, that particle is just vibrations. The apple in the image is, ultimately, good vibrations! (Image courtesy of Wikimedia Commons.)

    Scientific theories are supposed to have predictive power—you should be able to predict a consequence of the theory and then measure those consequences in the real world. So far nothing has panned out for string theory, which is why some people refer to it as a “theoretical framework.” There are some elegant mathematics behind strings, which is the primary reason why this area of study has survived from 1960’s until now. That and the fact it has cool jargon.

    For more information, see Brian Greene's TED Talk on string theory. 

  • Asymptotic Freedom: David Gross

    The STARMUS Festival in the Canary Islands claims to make “the most universal science and art accessible to the public.” The speakers are some of the best in their field and include physicists, astrophysicists, chemists, biochemists, biologists, neuroscientists, and economists. Many of them are nobel laureates. Although the festival claims to be aimed at the “public”, I suspect that many of those brainy nobel laureates don’t have a good idea of where the intellect of the pubic lays. That’s why I am looking at the conference program now to investigate some of the conference speakers’ areas of expertise. I hope that by knowing a bit more about some of the speakers’ interests, I’ll get more out of the conference.

    On the first day David Gross, who won the Nobel Prize in Physics in 2004, will discuss the great challenges faced by physics. One of his challenges was explaining the behavior of quarks by introducing the property of asymptotic freedom, an explanation for which he (and two others) received the Nobel prize. 

    What exactly is asymptotic freedom, or AF as I’ll call it? It doesn’t sound too daunting. I know what freedom is—being free to do or think what you want without being constrained. I know what an asymptote is—a line that approaches a curve but does not meet is. How does that relate to physics? Why would someone get a nobel prize for that?

    To understand AF, you need to have a basic understanding of atoms, those tiny things that make up matter. Atoms in turn are made up of subatomic particles—protons, neutrons, and electrons. While most of us are worried about how to keep our lives togethers, people like David Gross are concerned with how an atom keeps itself together. Physicists know there is a strong nuclear force that holds protons and neutrons in place in an atom, but they wanted to know more about that force, as it is one of the four fundamental forces in the universe. (The other forces are electromagnetic, weak, and gravitational.) 

    How strong is the strong force? Over very tiny distances—atomic nucleus sized—the strong force is 100 times stronger than the electromagnetic force that repels positively charged protons. That’s why an atomic nucleus stays together under normal circumstances.

    Both protons and neutrons are themselves made up of quarks—precisely three quarks. These days, quarks are assigned “colors”, either red, green or blue. This might see like an homage to the pixel, but using color as a metaphor in physics helps to explain a lot of subatomic particle interactions that I’m not going to explain in this discussion. (I’ll also ignore quark “flavors.”) Suffice it to say that subatomic particle interactions have to result in white. Red, green, and blue combine to white.  (Image from Wiki Commons.)

    So far you know that the quarks are held in place by a strong force. The theory behind this strong force is named quantum chromodynamics (QCD) because of the arbitrary use of color. That finally brings us to AF.

    AF is important because it explains some baffling behavior of quarks. You can’t see quarks, which indicates they are trapped in matter by the strong force. If they weren’t confined, you’d be able to see them, right?  Yet a big smash up at the linear accelerator down the road from me—Stanford Linear Accelerator (SLAC)—showed that in a high-energy reaction  the force between the quarks weakens and the distance between them decreases asymptotically. That is, they get closer and closer, but don’t run into each other.

    What  it boils down to is that quarks have two phases—confinement and AF. Much like water and steam, the phases depend on temperature. In the case of quarks, temperature (which is really energy) is measured in Mega electron Volts, or MeV. The phase change occurs at 160 MeV. Quarks are mostly confined below that energy level, and mostly have asymptotic freedom above that level.

    So what’s the lesson for the lay person? Although your personal life may seem to be falling apart, take comfort in the fact that the atoms around you are quite stable. You might need to expend a lot of energy to keep things together, but atoms are just the opposite.  

    AF isn’t all that Dr. Gross is known for. He is one of the signers of the Humanist Manifesto.

  • STARMUS 2016: Taking a Chance on a Warm Weather Vacation

    If you look at some of the places I’ve traveled—Jukkasjärvi, Barrow, Fairbanks, Puntas Arenas, Patagonia, Andes, Himalaya, and Antarctica—you might conclude that I am a cold weather person. I’m not. But when it comes to a vacation, the idea of sitting around on a beach might sound idyllic, bur for a week I think it would be quite boring. That’s what attracts me to STARMUS.

    STARMUS is a biennial festival celebrating astronomy, art, and music. Held in the Canary Islands, the festival is aimed at the public, but the speakers are luminaries like Stephen Hawking, Brian May (astrophysicist and guitarist in Queen), Jill Tarter (astrophysicist), and Roger Penrose (mathematical physicist). The conference sessions get underway at 3:00 PM each day and end at 8:00 PM. The parties start at 9:30 PM and last until 1:00 AM. There is just enough time in the late morning to sit by the sea, but not so much time that I’ll get bored. Most of my time in this warm weather destination will be spent doing interesting things. Or at least I hope so.

    The conference takes place June 27 to July 2. Between now and then I plan to do a little background reading so I can get the most out of the conference. Although I know who many of the speakers are, there are many whose names are unknown to me. It’s time to find out who they are! 

    This video from STARMUS 2014 gives an idea of what goes on at this festival.