Featured image above is from an article from 2013 where a group at Berkeley is working to make windows even smarter, in a different way.
In this special show for WPRB’s all-vinyl week, Brian covers the tunes and Stevie speaks to our guests, Princeton graduate researchers Nick Davy and Melda Sezen. It was beautiful chaos in the studio.
Nick and Melda work on Smart Windows, under Professor Lynn Loo in Chemical and Biological Engineering. “Smart Windows” refers to glass that can change colors (darken) when a current is applied. This happens due to the electrochromic (electro=electrical responding, chromic=color) material polyaniline. Polyaniline is magical. It dissolves in water, and is just green when no current is applied (see image), but when connected to an energy source, like a battery or a solar cell, it can be tuned to be varying shades of blue, and even transparent. Nick and Melda’s collaboration
works to improve this technology by introducing organic* solar cells as an extra varnish on the windows, producing both the energy needed to change the color of the glass and hopefully some excess to power your home, etc.
So, in the show we in to the nitty gritty of how smart glass works, and how Nick and Melda are fabricating and improving the technology. We then dive in to other applications of organic solar cells and polyaniline, for example wearable technology.
If you’re looking for something about smart windows that’s little higher level, take a look here.
At the very end of the show, Brian jumps on the mic to give us a little history of vinyl, including cylinder vinyl, and how LPs are made!
*In chemistry speak, “organic” = carbon based. In this case, think “plastic.”
This week’s interview features Dr. Paul Gauthier, an Associate Research Scholar in the Department of Geosciences here at Princeton University. As a plant physiologist, he’s an expert in plant behavior, including respiration and photosynthesis. Specificially, Paul researches the connection between environmental stresses and carbon balance within plants — how much carbon do they store (via photosynthesis) and how much do they exhale (via respiration)?
A key point that Paul stresses is the delicate balance most plants maintain between storing energy and releasing it. Like us, all plants have to breath all the time, expelling CO2 into the atmosphere. While the trunk, roots, and branches all respire, the leaves of the plant photosynthesize energy out of sunlight to store new energy for further growth. Every plant invests years and years of energy into stores for later growth: just check out this video of an acorn, which shows the slow growth from seed to shrub of an oak tree. All this energy had to be produced and saved by the parent tree that produced the acorn!
Paul’s science analyzing the carbon balance within plants goes from the lab (where sunflowers are his favorite specimen) to the natural forests of Sweden. There, Paul and his group can investigate the strange effect that 24-hour days can have on plants–imagine staying awake without a rest for two months on end, as all trees north of the Arctic Circle must do. Such stresses introduce interesting adaptations into the plants genes, which help them respire less, and thus hold on to their carbon more efficiently.
As climate change transforms the environment around us, plants are especially susceptible to small changes. Paul explains that a drought in California, made more common by climate change’s dramatic effects, can deplete a plant’s storage of carbon and energy. A particular tree may seem healthy as soon as extreme weather ends, but in reality it will take many years to bounce back from using up all its invested energy. In this way, it’s hard to measure the immediate impact of climate change on forests: detrimental effects may not appear for 8-10 years.
You can keep up on Paul’s research by following him on Twitter! @LabGauthier
Finally, Stevie and Brian end the show with a re-cap of gravity waves (which you’ve been hearing about all over the news this week, and as Stevie predicted on our previous show). The LIGO experiment successfully detected a faint signal of spacetime fluctuations, which match Einstein’s predictions exactly. Somewhere a billion light-years away, two massive black holes collided and caused a ripple in the fabric of our space to propagate toward the Earth–just in time for us to measure it! Physicists are hugely excited about the new possibilities this discovery gives us for understanding our universe, and we hope you’ll pay attention for new developments. Who knows what we’ll eventually find.
Featured image is an artist’s conception of gravitational waves from a binary system. From LIGO.org.
Image with the recording is of the inside of the Tate Britain museum in London.
The main portion of this show is an interview with Dr. Lora Angelova – a chemist and researcher at the Tate Britain in London, England. What this means is, she uses chemistry, material sciences, physics, art history – and whatever else she needs – all towards the effort of conserving art. Currently, her research focuses on developing methods of surface cleaning artworks. Throughout our interview she takes us through some of the work involved to keep a piece of art in a state as close to its original as possible, and how much of an effort that takes. It’s truly a labor of love.
In the interview we discussed her work with NanoRestART, and micro-emulsions. Lora explained micelles, and that lead us to how soap works. Then we spoke a little on the surface of our cells – as it’s a similar concept.
After the interview, I spoke for a while about gravitational waves. Here’s approximately what I said on them:
If I were a betting woman, I’d say that you’re about to hear a lot in the news about these entities called “gravitational waves.” That is, if you keep up with science and tech news.
On Thursday, the LIGO experiment is having a press conference. BUT it’s been rumored for months that they might have seen something in their instrument. LIGO stands for Laser Interferometer Gravitational-wave Observatory. And what they search for is, you guessed it, gravitational waves.
From general relativity we know that gravity – the force that makes apples fall and keeps us here on Earth, and maintains the Earth orbiting the Sun – isn’t like the other forces. The other three forces: the electromagnetic, strong, and weak forces – all operate via particle interactions. So if two objects are attracted or repelled due to the electromagnetic force, this comes about because of particle exchange. But when two objects are gravitationally attracted to each other, this comes about due to the fact that massive objects actually warp the spacetime around them. Like when you sit on your bed with lots of stuff on it and everything falls in to you. Alternatively, think of a rubber sheet pulled taught with a bowling ball set on it. The bowling ball warps the sheet, causing any marbles
you throw on to the sheet to fall in to the ball. This is how gravity works.
And, in our sky, we can see gravity do this due to its effect on light. Light always takes the shortest path through spacetime, so if spacetime curves due to some massive object, then the light will curve. This effect creates these fascinating images on the sky called Einstein rings – these are absolutely gorgeous and dramatic and totally incredible. You can see one of these to the right of this page, but google for images. There’s many.
So what’s a gravitational wave? Well, if gravity is curvature of spacetime, then a gravitational wave is an oscillation in spacetime. Think of it like a stretching and compressing of a small bit of space – first vertically stretched and horizontally compressed, then horizontally stretched and vertically compressed, and again and again, back and forth – but that stretching and compressing action is traveling, at the speed of light, away from its source.
The LIGO instrument uses this property – and lasers – to try to measure gravitational waves. Essentially, they have VERY very precise lasers aimed across a distance, and if this light from the laser is stretched or compressed just a little tiny bit, then LIGO will pick it up. And if that stretching and compressing has the right signature, then it could be a gravitational wave.
A good next question is, where does the gravitational wave come from? What’s the source? Well, a gravitational wave is theorized to radiate out from just about any massive, moving source. So this could be, for example, two neutron stars spinning around each other at fantastic speeds, colliding black holes. Or you, driving in your car.
A key thing to note is that gravity is SO MUCH weaker than any of the other forces. This is why a magnet that you hold in your hand could attract a paperclip via the electromagnetic force, but could never really attract anything gravitationally. If you’re in to numbers, gravity is about 30 orders of magnitude – that’s a 10 with 30 zeros after it – weaker than the electromagnetic force.
And this is why LIGO is looking to observe gravitational waves from two neutron stars spinning around each other at fantastic speeds, but isn’t worried about picking up the waves from you driving in your car. And this is also why it’s so hard – and why it’s never been done before. But LIGO has been diligent…and there have been rumors of discovery for weeks now. So…watch this space.
And just so you know – gravitational waves have never been directly observed before, but
it’s on very very strong theoretical footing. First off, they come out of General Relativity, which has been tested time and time again. And second, they have been measured indirectly.
Here’s what we’ve seen. As a system – like binary neutron stars or black holes – radiate gravitational waves, they lose energy… this will cause the objects to spiral in towards each other and eventually collide. And this has been observed! Cue the Hulse-Taylor pulsar.
In the Hulse-Taylor system a…
…decrease of the orbital period [was observed] as the two stars spiral together. Although the measured shift is only 40 seconds over 30 years, it has been very accurately measured and agrees precisely with the predictions from Einstein’s theory of General Relativity. The observation is regarded as indirect proof of the existence of gravitational waves. Indeed, the Hulse-Tayor pulsar is deemed so significant that in 1993 its discoverers were awarded the Nobel prize for their work.
So, we are pretty sure they exist. And if we are able to observe gravitational waves directly from sources like black holes and dark matter, that would be totally revolutionary for astrophysics! It would show us the universe us in a whole, brand new way.
And with that, we’re all pretty pumped to hear what LIGO has to say on Thursday. And sometime soon I’ll try to get someone from the collaboration in here to talk about it.
Feature image: Behold! The cosmic microwave background. It was emitted just after the universe was one big plasma. Credit: Planck HFI telescope.
Welcome to the new and improved These Vibes Are Too Cosmic. Brian Kraus and Stevie christen their new time slot of 5-7pm on Tuesdays. We introduce the new format for the show – we’re switching off taking the helm each week (next week Stevie, the week after that Brian, and so on) serving up steaming offerings of science and music.
But this week, in this new show we’re so pumped about, we decided to introduce our listeners to….ourselves. We play music we love, interview each other on our respective research fields, and take questions from listeners.
Plasma physics (Brian): I work on plasmas, which are basically electrified gases. Imagine the process of melting a solid, and then boiling a liquid: in both cases, the atoms in the material are more and more free to move around as they gain energy. In a plasma, the electrons around the atoms have enough energy to escape the atomic nucleus, and what you’re left with is a gas of charged particles: negative electrons zooming around the heavier positive ions. You’d know a plasma if you saw one: they glow, like the plasma ball to the right or the lightning during a rainstorm.
The applications of plasma are numerous – from lightbulbs to space propulsion – but the most famous reason to study plasmas is to make fusion energy. This is the nuclear process where small atoms collide together to form bigger ones, which results in a huge energy gain for fused particles. Fusion energy could become a safe source of power, driving electrical grids with energy from seawater. The main issue is plasma containment, which means we have to keep the hot plasma (often at 10 million degrees C) from melting the walls of the container we keep it in. The most common device for magnetically confining a plasma is called a tokamak, which is basically a donut that keeps particles spinning around on a racetrack as they heat up.
My own work concerns measuring properties of plasmas with probes. Since the plasma is an electrified gas, it can conduct currents and respond to voltages – which are very easy to tap into by sticking a metal wire in the middle of the plasma! By varying the bias on the metal probe (putting stronger or weaker batteries on it), I can push or pull on the electrons in the plasma. Through this general method, we can deduce the plasma’s temperature and density at many points, so we have a good map of what it’s actually doing.
You can learn a lot more about plasmas, and my work studying them, by listening to an older show where Stevie interviews me about all of this in greater detail.
Observational Cosmology (Stevie): I work on the SPIDER instrument, a telescope with the aim to measure the polarization in the cosmic microwave background radiation (CMB, the featured image up top). The CMB is, believe it or not, microwave radiation that bathes our entire universe. Not only is this radiation the oldest in our universe, it serves as a snapshot of our universe at that time it was emitted – over 14 billion years ago. Since it’s discovery in the 1960s (a great story unto itself), we’ve learned the CMB (like our universe) is almost entirely homogeneous and isotropic, but with tiny variations that map to density perturbations in
our early universe. These perturbations were the seeds of all the astrophysical structures we see around us today. Currently, the cosmic background radiation is our richest source of information on the evolution and large scale structure of our universe.
At only 2.7 degrees Kelvin, this radiation is difficult to measure, but not impossible. It is still just light with a defined energy ( = wavelength) and polarization. Through decades of effort scientists have carefully mapped the temperature of the CMB. Now, the forefront of observational cosmology is to map the polarization. Incredibly, the patterns in the polarization of the CMB have the capacity to
tell us about our universe back before the CMB was even emitted, pushing our understanding of our universe back to a time just moments after the Big Bang.
The SPIDER collaboration manages this task by cooling polarization-sensitive detectors to
less than a degree above absolute zero, and then sending them to the edge of space for a 20 day flight in weather balloon above Antarctica. SPIDER’s first flight was last January (2015). The flight was successful. We’re currently analyzing our rich new data set and preparing for a second flight in the next few years. As a grad student on this project, I’m pretty psyched.