Category Archives: lectures

Our favorite Seattle astronomy events from 2015

Happy New Year from Seattle Astronomy! Yesterday we ran down our top five news stories of the past year. Today, let’s take a look back at our top talks and events from 2015.

Comet Hunter

Scheiderer and MachholzRenowned comet hunter Don Machholz was the keynote speaker last year at the annual banquet of the Seattle Astronomical Society. Machholz has discovered eleven comets visually, without the aid of CCD cameras and other modern aids, and that’s the record. He does it the old-fashioned way, sitting at the eyepiece for hours at a time and sweeping the sky for something that wasn’t there before.

Machholz told a wonderful tale about his techniques of comet hunting and about the intensely personal reasons that drove him to the quest. It was an informative, touching, and often hilarious presentation filled with images and music.

It’s all relative

Jeffrey Bennett at the UW's physics/astronomy auditorium. Photo: Greg Scheiderer.

Last year was the international year of light and marked the 100th anniversary of the publication of Einstein’s theory of relativity. Jeffrey Bennett toured the country to help us better understand relativity, and stopped in at the April meeting of the Seattle Astronomical Society to give a well-received talk about the concepts of relativity. Bennett is an engaging lecturer and his book, What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter, (Columbia University Press, 2014) is a big help, too, that makes a topic that is so mind-bending and daunting to so many truly accessible to a broader audience.

We did a preview interview with Bennett as well.

Physics pioneer

Jim Peebles

Science is mostly about brainpower and creativity, and testing, but there’s some luck involved, too. Case in point: back in 1965 Jim Peebles and colleagues at Princeton were on the hunt for what we now know as the cosmic microwave background, the lasting signature of the Big Bang. Up the road at Bell Telephone Labs, Bob Wilson and Arno Penzias had found the CMB, but didn’t realize what they had! To the latter went the Nobel Prize, but Peebles has been in the forefront of research on the CMB for the past 50 years. We now know a lot about the history of our universe, except for the first fleeting moments that remain a mystery. Peebles talked about that history at a UW lecture in May.

Space tourist

SimonyiCharles Simonyi shelled out a lot of cash to fly to the International Space Station in a Soyuz capsule with the Russians—speculation is that his tab for two trips, in 2007 and 2009, came to about $60 million. Simonyi gave a talk at the University of Washington in September about the practicalities of space travel, and when it might be possible for those of us with somewhat lesser means.

The answer, sadly, is not that soon, but Simonyi envisions a day when the cost of launching a kilogram of mass into space might be driven down to $100, and that might make the cost of space travel something that more people could consider.

Simonyi’s story was an entertaining one that was as much about the training for his two trips to space as it was about the technical aspects of getting there.

Dark matter and the dinosaurs

Lisa RandallHarvard particle physicist and author Lisa Randall has a new hypothesis about what may have killed the dinosaurs on Earth. It’s a surprisingly simple notion, at least once you get past the fact that it depends on a new sort of particle that we haven’t yet detected.

Randall spoke at Town Hall Seattle in November about her ideas and her new book, Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe (Ecco, 2015). The theory in a nutshell: suppose that there’s a type of dark matter that interacts with light. Such dark matter could collapse into a disk, just like our galaxy. As our solar system orbits the galaxy, we periodically go up and down through the galactic plane. Passing through the plane would also move us through this disk of dark matter, which could gravitationally dislodge comets from the Oort Cloud and send them hurtling our way.

It is an interesting idea that Randall says she’ll devote much time to testing in the coming years.

Honorable mention on our list: the lecturers of the Big Bang and Beyond series at the UW, including Andy Connolly, Miguel Morales, Julianne Dalcanton, and Adam Frank; George Musser, who spoke about his book Spooky Action at a Distance: The Phenomenon That Reimagines Space and Time–and What It Means for Black Holes, the Big Bang, and Theories of Everything (Scientific American / Farrar, Straus and Giroux, 2015); and Curiosity rover chief engineer Rob Manning, who gave a talk based on his tome Mars Rover Curiosity: An Inside Account from Curiosity’s Chief Engineer (Smithsonian Books, 2014).


The power of unseen light

Megan Watzke thinks about light a lot. Watzke is press officer for the Chandra X-ray Observatory, and she’s the co-author of three books: Light: The Visible Spectrum and Beyond (Black Dog & Leventhal, 2015); Your Ticket to the Universe: A Guide to Exploring the Cosmos (Smithsonian Books, 2013); and Coloring the Universe: An Insider’s Look at Making Spectacular Images of Space (University of Alaska Press, 2015). Watzke gave a talk about Light at Town Hall Seattle last week.

Watzke pointed out that there are seven different categories of light, and we’re all familiar with them all, and yet sometimes we forget that it’s all just light.

“Light in its vaiorus forms is not different,” she said. “It’s the same phenomenon, it’s just different wavelengths.”

“We use these different types of light every single day,” Watzke added, “or we’re affected by them every single day.”

Watzke said the seven categories are a bit arbitrary and move around a bit depending on the science being done. But they all share similar characteristics. They travel at the same speed, and can bounce and bend or be absorbed or blocked. It’s at different wavelengths that it does different things, and the wavelengths can vary from miles to less than the width of an atom.

Seven categories of light

Radio waves. The longest wavelength, Watzke pointed out that we don’t actually hear radio waves, but that electronics translate the changes in compressed air created by sound. But our mobile phones, GPS devices, bluetooth headsets, MRI tests, and garage door openers all use radio waves.

Microwaves. We use them to cook things, and satellite TV trucks use them to beam video around the world.

Infrared light. Infrared light has many uses. Your TV remote control employs infrared, which can also be used to create warmth. Astronomers can see celestial objects in the infrared when visible light is blocked by interstellar dust.

Visible light. A tiny part of the spectrum. Watzke said that if all of light was a piano keyboard, what we can see would be a few keys around middle-C. But it’s important, as it is why we can see things, is a source of sustainable, non-fossil-fuel energy, and is a key to photosynthesis.

Ultraviolet. UV light can cause sunburn, but can also be useful to destroy microbes, and is used for security on currency or credit cards. Ultraviolet also includes black light, which Watzke joked is an “important part of raves and Halloween parties.”

X-rays. We all know about the medical uses of X-rays, which can cause cancer or be used to combat it. In astronomy objects emit X-rays if they’re extremely hot or energetic, like material falling into a black hole.

Gamma Rays. Watzke called gamma rays the “most energetic thing we know about.” They can be harmful, but like ultraviolet can kill microbes and also has uses such as the sterilization of food.

False color

Megan Watzke

Author Megan Watzke explained the powers of the different wavelengths of light during her talk Dec. 8, 2015 at Town Hall Seattle. Photo: Greg Scheiderer.

Watzke took some time to talk about the term “false color,” which she finds to be a misnomer. She said false color is not fake color. When scientists create images in false color they are simply trying to represent light that we cannot actually see.

“What is done with scientific images that involve invisible wavelengths is that color is applied to wavelengths and then stacked together, frequently, so you have multiple layers that look like a multiple-color image,” Watzke said. “These are real data, but a layer of color is applied.”

“It’s translating the data that is invisible into something that you can actually see,” she added, comparing the process to the way one would use color to represent different temperatures on a weather map.

She would prefer the term representative color; perhaps it will catch on!

Watzke will talk more about the creation of astronomical images when she discusses Coloring the Universe along with co-author Travis Rector at Wednesday’s meeting of the Seattle Astronomical Society.

Watzke said that she wrote Light to make the topic a little more accessible.

“I want people to understand that light is all around us and that science is all around us,” she said. “Science isn’t something to be scared of or be intimidated by. It’s something that we all should be able to enjoy and pursue.”

More information:

  • Recording of Watzke’s talk from Town Hall Seattle
  • The trailer for Light, below


Answering the ultimate questions

There is a crisis in physics today, but Adam Frank sees it as an opportunity rather than a threat. Frank, a professor of astrophysics at the University of Rochester and co-founder of NPR’s 13.7 Cosmos and Culture blog, gave a talk last week at the University of Washington titled, “Beyond the Big Bang: Cosmology and Ultimate Questions.” Frank, who earned his master’s and doctoral degrees at the UW, was back on campus for the last in a series of lectures titled The Big Bang and Beyond, which was sponsored by the university’s alumni association as part of the celebration of the 50th anniversary of the Department of Astronomy.

Modern mythology

Frank called the Big Bang a bit of “modern mythology,” an origin narrative that puts us into a cosmic context and gives the universe meaning.

Adam Frank

Adam Frank, professor of astrophysics at the University of Rochester and frequent NPR science commentator, gave a lecture at the University of Washington Dec. 2, 2015. Photo: Greg Scheiderer.

“Science tells us that there is no meaning,” Frank noted. “We can argue about that. But even not having a meaning is meaning. In that sense the Big Bang is a powerful origin myth for our culture.”

While he called it an origin narrative, Frank pointed out that many people have a misconception about the Big Bang Theory.

“It is not a theory of the beginning,” he pointed out. “The Big Bang never tells you why it’s there.”

It gets close; within about 10-32 seconds of the start.

“We can do a pretty good job of telling you in detail what the history of the universe had been going back to some tiny fraction of a second after the Big Bang,” Frank said.

Fine tuning

That tiny fraction of a second is where some weighty riddles reside. For the Big Bang to work, we have to assume that the initial conditions were the same as they are now. There’s a lengthy list of constants in the math that describes the universe, such as the speed of light and the gravitational constant. All of them have to be just so.

“You change one of those numbers by just a tiny amount and life could never form,” Frank noted. So how did we end up in a universe that is perfectly fine tuned for us to arrive on the scene?

“If you’re an intelligent design person you say, ‘Oh, it’s God that did it,’” Frank said. “If you’re a physicist, that’s not going to work very well for you. What you want as a physicist is a theory that predicts these.”

“People often talk about cosmology as being the place where science butts up against theology, but physicists don’t want that to be the case,” he continued. “They want to have coherent physical explanations for something like where the Big Bang came from.”

Coherent is in the mind of the beholder, but it may well be that such an explanation has yet to emerge. Frank refers to the most prominient ideas so far as the “standard crazy” and the “alternative crazy.” And it’s from these crazy ideas that the crisis emerges.

Standard crazy

The first standard crazy idea is that of multiverses. With an infinite number of universes popping up all over, fine tuning is no longer an issue. There’s bound to be a universe with our exact conditions, and that’s the one we live in.

Then there is string theory, which arose out of the search for a quantum theory of gravity. String theory can reproduce standard-model particles, and it includes a gravity particle. People got pretty excited about a “theory of everything.”

There are problems within the standard crazy. Unobservable multiverses. Hidden dimensions. The existence of 10500 universes. And it all may lie beyond possible experimentation.

“People are really starting to push back on multiverse and string theory—these ‘standard crazy’ ideas—saying these things may be untestable,” Frank said. “If they’re untestable they’re not science, and if they’re not science it’s time for people to stop talking about them.”

“All of the work that was done on string theory and the multiverse may, in the end, turn out to be, in some sense, a wrong direction,” he added.

Alternative crazy

Other far-out ideas have been proposed. British physicist Julian Barbour puts forward the notion that time doesn’t exist, and that every moment is a distinct and separate now. Lee Smolin suggests that we reboot cosmology entirely, and consider that our “timeless” laws are anything but; that physical laws may in fact be evolving.

“It could be totally wrong, but it’s illustrative of the difference of where you have to go to try and think about going beyond and before the Big Bang without getting into the conceptual problems that string theory and the multiverse lead to,” Frank said.

A good crisis

Frank sees this crisis in physics as an opportunity.

“The crisis in phyics is great because what it’s going to mean is that we’re going to have to come up with even different ideas,” he said. “We’re going to have to probe our understanding of reality even deeper, and what we’re slowly heading toward is some kind of truth. It may not be the ultimate truth, but we’ve been approaching a better understanding of the world since science has begun.”

Frank said that, with a seemingly endless stream of terrible headlines in the news, he sees the search for this ultimate reality as an example of what we do best.

“Humanity is capable of such incredible stupidity and horror, and yet we’re also capable of such compassion, and such wonder, and the ability to experience such awe,” Frank said. “The quest for ultimate reality is a fundamental expression of human goodness and hope.”

More reading

Books by Adam Frank


Aperture fever strikes in the hunt for dark matter

There’s a truism in astronomy that aperture rules. The wider your telescope mirror or lens the more photons you can capture and the better views you’ll get of celestial objects. It turns out that aperture fever strikes professional astronomers as well as amateurs. The latest to fall victim to this malady is Julianne Dalcanton, professor of astronomy at the University of Washington. Last week Dalcanton gave a talk at the UW titled “Building the Universe Piece by Piece.” It was part of the lecture series The Big Bang and Beyond being presented by the UW Alumni Association in celebration of the 50th anniversary of the university’s Department of Astronomy.


Prof. Julianne Dalcanton spoke about galaxy formation and evolution at the UW Nov. 18. 2015. Photo: Greg Scheiderer.

Dalcanton’s bailiwick is the study of the formation and evolution of galaxies, and she picked up that story where Miguel Morales left off two weeks before in the second lecture of the series. Morales took us up to the “end of the beginning,” the release of the cosmic microwave background, 380,000 years after the Big Bang. Once things cooled down after that, the universe developed more complexity.

“You have intergalactic gas that originally permeated the universe mixed with the dark matter and the light of the cosmic microwave background,” Dalcanton said. “This gas has funneled, along with the dark matter, into these increasingly rich structures and then funneled into galaxies.”

As the galaxies formed, so did stars out of even more densely concentrated areas of gas. Dalcanton noted that the Hubble Space Telescope has given us marvelous photos of stars being born in places like the Orion Nebula or the Eagle Nebula, subject of the now-famous photo “Pillars of Creation.”

Beautiful and deadly


“The Pillars of Creation” is arguably Hubble’s most famous photo. Image: NASA, Jeff Hester, and Paul Scowen (Arizona State University) –

“These scenes of great beauty are scenes of great destruction,” Dalcanton said. “The stars that are born here are the ultimate in ungrateful children. They are just going about their business absolutely destroying the cloud from which they were born.”

Dalcanton pointed out that we can recognize young stars easily because they’re massive, bright, blue, large, and hot. They tend to flame out quickly. On the other hand, smaller, cooler, dimmer red stars like our Sun last a lot longer.

“They all seem so different,” Dalcanton said. “There’s a clear regularity in their properties that must be directly linked to the physics that’s going on inside the stars.”

By looking at other galaxies and noting the distribution of young and old stars, astronomers get clues about how the galaxies evolved and how elusive dark matter works. Then they make computer models and compare the results to what they see around the universe. The theoretical models match the observations pretty well so far.

“Just because you can make it in the computer doesn’t mean that it’s true,” Dalcanton cautioned. “The study of the individual stars and the actual histories of individual galaxies, where we can pick them apart into their individual pieces, gives us a really strong constraint on all of these models. That then gives us the additional leverage to try to break apart various possible theories of dark matter.”

“The key ingredient to all of this is actually detecting individual stars,” she added.

We need a bigger telescope

This is where the aperture fever comes in.

Dalcanton heads up PHAT, the Panchromatic Hubble Andromeda Treasury, a project in which Hubble made nearly 13,000 images of the Andromeda Galaxy and did a billion measurements of 110 million stars. Volunteers in the Andromeda Project helped sift through nearly a terabyte of data, and we learned a lot.

“As awesome as this is, Hubble is not enough,” Dalcanton said. “Hubble’s my babe, but it’s got its limitations.”

She said Andromeda was chosen for this survey because it is the closest, most massive spiral galaxy we can get a good look at.

“Even with the Hubble Space Telescope we can’t really pick apart all of the stars that we actually want to,” Dalcanton said.

HDST is the answer

The HDST would dwarf Hubble or the James Webb Space Telescope, planned for launch in 2018. Image: C. Godfrey, STscI.

The HDST would dwarf Hubble or the James Webb Space Telescope, planned for launch in 2018. Image: C. Godfrey, STscI.

That’s why she’s a big advocate for a new project on the drawing boards called the High Definition Space Telescope (HDST). Hubble’s mirror is 2.4 meters. HDST’s would be nearly 12 meters, and would have 25 times the surface area of Hubble. Dalcanton said that would give it vastly superior sensitivity and clarity.

“We would see fainter stars and we would see them in regions of the universe where they were much more closely packed together,” she said. It would be like going from an old tube TV to your new 60-inch high-definition television. HDST would be strong enough to spot planets orbiting relatively nearby stars, and could see more and more stellar nurseries like the Eagle Nebula.

“We would be able to see those in individual galaxies anywhere in the universe,” with the HDST, Dalcanton said.

“That’s what I’m rooting for.”


The end of the beginning of the universe

Miguel Morales has been spending a lot of time pondering what he calls “the end of the beginning of the universe”—the cosmic microwave background. Morales, professor of physics at the University of Washington, heads up the university’s Dark Universe Science Center, a group working to figure out gravity, dark matter, dark energy, galaxy formation and evolution, and other cosmological mysteries. Morales gave a talk earlier this month titled “The End of the Beginning.” It was the second of a four-part lecture series, The Big Bang and Beyond, sponsored by the UW alumni association in celebration of the 50th anniversary of the Department of Astronomy.


The now-famous rendering of the cosmic microwave background “looks like Pollock. It’s kind of a mess!” jokes Prof. Miguel Morales. Yet it may hold clues to how the universe formed and how we all got here. Image: ESA and the Planck Collaboration.

Morales gave a “Cliff’s Notes” history of the formation of the universe, noting that the end of the beginning came about 380,000 years after the Big Bang, when the hydrogen and helium plasma formed by that event cooled sufficiently to change phase and release light.

“It froze from an opaque helium hydrogen plasma to a clear, neutral gas,” Morales explained.

The “glowing wall of gas” left behind is the cosmic microwave background. Recent measurements have confirmed temperature fluctuations in the CMB.

“These are real, hot and cold spots that we see on the sky,” Morales said. “This is the writing of creation on the wall.”

Ghostly evidence

Morales noted that this writing is extremely faint. He pointed out that the differences between the red an blue sections of the now-famous Planck map of the cosmic microwave background are just one part in 100,000.

Miguel Morales explains how oscillations in plasma created sound waves that can be spotted within the cosmic microwave background. Photo: Greg Scheiderer.

Miguel Morales explains how oscillations in plasma created sound waves that can be spotted within the cosmic microwave background. Photo: Greg Scheiderer.

“This is really a testament to precision measurement,” he said. He noted that, given this level of accuracy, we can learn a lot about what was going on in the early universe from the evidence left behind.

For example, scientists have teased out sound waves from the cosmic microwave background. The waves were created when the plasma oscillated in what was essentially a tug-o-war between gravity trying to collapse the mass and photons resisting that force. How those sound waves propagate could hold clues to what was going on in the early universe.

Changing tactics

The early observations measured temperature, but Morales said the state of the art is to look at the polarization of the light, which could lead to a needle in the cosmic haystack.

“You might be able to see, in the polarization, the ghost of gravity waves from inflation,” he said. They actually thought they had something in observations from the BICEP2 telescope at the South Pole, but what they saw actually turned out to be spinning dust.

“The polarization that BICEP saw is contaminated by the galaxy,” Morales said. “We’re seeing stuff on the windshield here; it’s not all primordial.”

One of the greatest challenges in making these observations is fine-tuning the instruments to ignore the noise and not be faked out by the data.

“BICEP is a technical tour de force, the measurement is awesome. It’s just a little contaminated, and, to be honest, Planck is not sensitive enough to say how bad the contamination is,” Morales explained.

That, he said, is science.

“We’ll keep looking, scratching our heads, building yet more sensitive instruments as we learn to read the words about the universe written faintly on the sky.”


Spooky action explained

Some eighty years ago Albert Einstein derided the notion of quantum entanglement as “spooky action at a distance.” Today, according to author and journalist George Musser, “We’re starting to see the hazy outlines of an answer,” to questions about the how particles in different locations appear to act on each other. He is quick to add that there are still scientists who don’t really believe that non-locality is a real thing.


Author George Musser explains separate particles magically acting on each other during his talk Nov. 3 at Town Hall Seattle. Photo: Greg Scheiderer.

Musser is the author of Spooky Action at a Distance: The Phenomenon That Reimagines Space and Time—and What It Means for Black Holes, the Big Bang, and Theories of Everything (Scientific American / Farrar, Straus and Giroux, 2015). He spoke about the book and the science earlier this month at Town Hall Seattle.

Musser noted that Einstein was clearly bothered by some aspects of quantum mechanics, particularly the notion that randomness governs the universe. This led to his famous observation that God does not place dice.

“It was arguably Einstein’s number one concern,” Musser noted. “His deeper worry, actually the worry that led him to the worry about randomness, was the worry about non-locality. What is non-locality? How can this magic sorcery kind of thing be happening in the real world?”

That’s the quality that got Musser interested in writing about the subject.

“It’s the closest thing that we have in contemporary science to real, honest-to-god, Harry Potter magic,” he said. He noted that it turns up in many different sciences, and isn’t just a “freak show” over in quantum mechanics.

Space is constructed

Muster detailed the experimental evidence that has established that entanglement is a real phenomenon. String theory, loop quantum gravity, and other attempts to explain what’s happening have, at their cores, a similar idea, according to Musser. That idea is that space isn’t just empty and out there; it’s made of something.

“Anyone working on quantum gravity thinks that at some level space is constructed,” Musser explained. “That gives you the opening to deal with non-locality. No longer is that an insoluble puzzle that has been hanging in the air since Einstein’s days.”

Muster suggested thinking about water to illustrate the idea. A single molecule of H2O does not have the properties of water. It’s only when you get a whole bunch of that molecules together that water can flow or have surface tension.

“Likewise, if space consists of atoms, each individual atom is not spacial. Each individual atom lacks the properties we associate with spacial things,” Musser said. “Those spacial properties are derived collectively from the interactions among atoms.”

Given that idea, it’s possible that space can also change its state, just like water can boil and evaporate or freeze, and perhaps that’s part of what is driving our perception of different locations and entanglement.

“It seems that these things are in a predetermined location, but maybe that quality of being in a predetermined location is actively being generated all the time, below our level of consciousness, below the level even of our theories,” Musser said. “There’s some deeper machinery in the natural world.”

It’s a complicated concept to work into a 500-word blog post or a 45-minute lecture. You can listen to an audio recording of Musser’s talk on the Town Hall Seattle website. He is an engaging speaker, and Spooky Action at a Distance promises to be a good read.


Tough choices Wednesday on week’s busy astro-calendar

There are several great astronomy events on the docket for this week. Unfortunately, three of them are at the same time on Wednesday.



The celebration of the 50th anniversary of the Department of Astronomy at the University of Washington continues with another of the lecture series The Big Bang and Beyond. UW astronomy professor Julianne Dalcanton will give a talk titled “Building the Universe, Piece by Piece.” Dalcanton will highlight the unique role that the Hubble Space Telescope has played in shaping our understanding of galaxies and stars as she illuminates the complex forces that have shaped the universe we see around us. She will also talk about the future of space exploration and how it will shape future discoveries about the universe. All free tickets have been claimed for the talk, scheduled for 7:30 p.m. Wednesday, Nov. 18 in room 120 of Kane Hall on the UW campus in Seattle. There will be a waiting list in the event of no-shows.

AOT in the Star Wars spirit

aotnovIf you prefer a little beer with your astronomy head over to Bad Jimmy’s Brewing Company in Ballard Wednesday for another Astronomy on Tap Seattle event. It’s the ninth monthly event in the series, being presented by graduate students from the University of Washington. It’s so popular that Bad Jimmy’s named a brew especially for AoT: the Big Sipper, a Scotch Ale. (It’s yummy.)

This month the topic is planets with two stars. Guest speakers will give brief talks about “How to Find a Tatooine” and “How to Build a Tatooine.” The event is set to coincide with a certain movie release. We’re not sure which one, as they’re not saying. Astronomy, trivia games, prizes, fun, and beer get under way at 7 p.m. It’s free, but RSVP.

SAS takes on photography

saslogoThe Seattle Astronomical Society will hold its monthly meeting Wednesday, Nov. 18 at 7:30 p.m. in room A102 of the Physics/Astronomy building on the UW campus in Seattle. The club’s former president, Denis Janky, will give a talk titled “Astrophotography With a Large Dobsonian Telescope and Color CCD Camera.” Janky is a long-time visual observer who only recently began dabbling with astrophotography. He uses a Mallincam Universe color CCD camera with an Obsession Dobsonian telescope. The Obsession has a tracking system, but is designed for visual observing. The Mallincam has capability for real-time observation on a computer screen and is also a full-fledged color CCD camera. Janky will show his setup and explain how it works.

The club will also hold its election of officers for the coming year.

Eastside Science Café

logo-233x751The Eastside Science Café tackles an astronomy topic this month. Matt Tilley, a Ph.D. student in the UW Astrobiology Program, will give a talk titled “The Magnetospheres of Solar System Planets and Beyond” at 7 p.m. Tuesday, Nov. 17 at Wilde Rover Irish Pub in Kirkland. Tilley will talk about how the Earth’s magnetic field shields us from deadly solar radiation. He’ll look at other planets and discuss how magnetic fields might be used to explore planets light years away.

Science cafés are a program of Pacific Science Center.

Saturday star parties

Both the Seattle and Tacoma astronomical societies plan public events for Saturday, Nov. 21. SAS will hold its free monthly public star parties at Green Lake in Seattle and Paramount Park in Shoreline. Both will get under way at 5 p.m., weather permitting. Tacoma Astronomical Society‘s public night at the Fort Steilacoom campus of Pierce College will begin at 7:30 p.m. with a presentation about the New Horizons mission to Pluto. Telescopes will come out for observing if the weather cooperates.

Track upcoming events on the Seattle Astronomy calendar.