In this episode of These Vibes, Stevie spoke with Dave Seal, a mission planner on the Cassini space probe which spent many years orbiting Saturn. Cassini operated its final maneuver, called the “Grand Finale,” and ended its observing by plunging in to Saturn just last Friday morning at 8am EST. It took a final image and took it’s last bits of data on Saturn’s atmosphere before being destroyed. Listen in to learn about the mission, its development, goals, and discoveries, and learn more about what it’s like to be a mission planner on a NASA space probe.
All that plus great music, and science news from microplastics in our seasalt to the new research on cancer cells.
Featured image is from Eyewire the connectome project run by Sebastian Seung at Princeton University.
Image in the Mixcloud embed above is from the Human Connectome Project at the University of Southern California.
This show is a little different. The plan was to have author and professor Patrick Phillips on for the first hour, alas there had to be a rescheduling at the last minute. Instead we will be interviewing Patrick Phillips on his book Blood at the Root at the end of next month (January 2017), so stay tuned.
Hour 1: Lots of music and some science news, including self-driving cars. Hour 2:Thomas Macrina on machine learning, neuroscience, and mapping our brain – our connectome. Hour 3: Kasey Wagoner, lecturer in physics at Princeton, on the bedrock scientific principle called the Equivalence Principle. In this discussion, Kasey tells us about the history, the principle’s importance, and current tests.
Featured image is from NASA. See below for explanation and credits.
It was a bit of a chaotic show in the studio. Just before start, we were told that our show would be interrupted a half hour in by basketball. Plans were thrown out and the drawing board went up. Blessedly, the sports only hijacked our live-stream. The day turned in to a beautiful show of music, with a great discussion on dark matter just before the end (around 1.5 hours in). The planned airing of an interview on exoplanets with astronomer and TED fellow Lucianne Walkowicz has been postponed.
The featured image for this post is from NASA. It’s the famed bullet cluster we mentioned so many times on the show! Two galaxies clusters collided, producing the image. Hot gas from normal matter colliding and interacting is in pink, and dark matter is in blue. You can see the dark matter just flew right past everything, maintaining its spherical shape.
This composite image shows the galaxy cluster 1E 0657-56, also known as the “bullet cluster.” This cluster was formed after the collision of two large clusters of galaxies, the most energetic event known in the universe since the Big Bang. Hot gas detected by Chandra in X-rays is seen as two pink clumps in the image and contains most of the “normal,” or baryonic, matter in the two clusters. The bullet-shaped clump on the right is the hot gas from one cluster, which passed through the hot gas from the other larger cluster during the collision. An optical image from Magellan and the Hubble Space Telescope shows the galaxies in orange and white. The blue areas in this image show where astronomers find most of the mass in the clusters. The concentration of mass is determined using the effect of so-called gravitational lensing, where light from the distant objects is distorted by intervening matter. Most of the matter in the clusters (blue) is clearly separate from the normal matter (pink), giving direct evidence that nearly all of the matter in the clusters is dark. The animation below shows an artist’s representation of the huge collision in the bullet cluster. Hot gas, containing most of the normal matter in the cluster, is shown in red and dark matter is in blue. During the collision the hot gas in each cluster is slowed and distorted by a drag force, similar to air resistance. In contrast, the dark matter is not slowed by the impact, because it does not interact directly with itself or the gas except through gravity, and separates from the normal matter.
In the last half hour of the show Brian and I, and our friend and fellow DJ Tristan, spoke about dark matter for a while. Honestly, the wikipedia page for dark matter is great if you’re looking for more information on the topic.
Photo credit where credit is due: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.
Check out the band, Gulps! They’re a new, totally rockin’ local New Jersey band that’s playing a lot of shows.
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.
Happy Christmas, listeners! In this rockin’ show Lucianne Walkowicz called in to WPRB from the Adler Planetarium in Chicago, where she works on NASA’s Kepler Mission as well as the Large Synoptic Survey Telescope (a telescope currently being built down in Chile). In this interview we focus on the Kepler mission’s search for exoplanets – these are planets outside of our solar system. We discuss questions such as: What makes a planet habitable? How does a star’s properties influence the planet’s habitability? How does Kepler go about finding these planets when they’re so much smaller and dimmer than their accompanying star? How could we know if there is life on these planets? And much more!
In this show Brian and I discuss what’s called “Big Science.” What we mean when we use that descriptor, and some of the amazing examples across the science fields including satellites to undersea observatories to particle colliders and fusion reactors. We also discuss some of the overwhelming obstacles to big science — from funding to choosing a project a whole field agrees on to getting thousands of scientists across the world to collaborate smoothly. There are positive and less so examples of these, and we mention several. Additionally, we dig a little bit in to how we got here. How big science projects became necessary, when they weren’t just decades prior.
And interweaved with all of that is, as always, music.
Discussion begins at about 3 minutes in.
(Cover image of the recording is from the ALICE experiment (one of the four detectors at interaction points in the Large Hadron Collider) at CERN.)
Music and interview with Princeton plasma physics doctoral student Brian Kraus. We talked about what is a plasma, the difference between fusion and fission, why fusion energy is so much cleaner than fission (what’s done in nuclear reactors), but also so much harder. We talked about the fusion reactor being built in France – ITER – as well as other things you can do with plasmas, like propelling satellites and space ships!
This is my first show at my new time slot: 2-4am on Thursday mornings. I played about a half hour of tunes, then the first 15 minutes of my interview on quasicrystals with Princeton Professor Paul Steinhardt.
Featured image is of a two-dimensional organic quasicrystal. Source: Natalie Wasio et al., Nature, 2014 via Wired
Image accompanying the Mixcloud link below is an actual image of a “Real Decagonal Quasicrystal with Quasi-unit cell tiling superposed.” Source: Paul Steinhardt (website)
This is my full interview with Paul Steinhardt, Albert Einstein professor of physics at Princeton University. We spoke about the magnificent quasicrystal – what it is, why they’re special and fascinating, and their incredible discovery (both of the synthetic and natural varieties). This is a fast-moving and hot area of research, and there is surely more to come soon.
Update: This was one of my (Stevie’s) first science interviews on WPRB (read: first interviews ever), and Paul was gracious enough to come in and spend the time with me, nonetheless. Sitting at the mic in the mirror studio, he relayed the whole story of how he became fascinated by quasicrystals, a crystal with a quasi-periodic structure and ten fold symmetry that is both mathematically interesting and, it turns out, can have desirable physical properties, like as coating on airplane wings and non-stick frying pans. This eventually led Steinhardt and his team on a quest to the farthest reaches of Russia for a naturally occurring sample that scientists had previously thought couldn’t exist as it would be too fragile. (Though! Quasicrystals were accidentally made in a lab in 1982.)
Listen to the whole story by clicking on the link at the top.
Indeed, the first naturally occurring quasicrystal was found by Paul and his team in 2009, and the second just last year in March 2015. The origins of the crystal are unknown, but due to its atomic makeup and the conditions required for its formation, the best theory involves meteors colliding in space. Steinhardt explained the theory in this interview, and further in an excellent Scientific American article on the topic (emphasis added):
The ratios of isotopes of oxygen in silicate and oxide minerals around the quasicrystal grain are typical of minerals found in meteorites called carbonaceous chondrites, the team reports. This indicates that the rock is of extraterrestrial origin and very old: virtually all chondrites formed at the birth of the Solar System. It is likely, but not certain, that the quasicrystal grain within the meteorite is of roughly the same age. It was found entwined with a silica mineral that forms only at high pressures and temperatures—such as might be created by a collision with the chondrite body.
This was a nerve-wracking show. At 38 minutes in I play the first half of my freshly edited interview with Dr. Reneé Hlozek, and it continues to 10 minutes in to the 2nd hour. Check out the audio and accompanying visuals here, on a separate post. Enjoy!