Category Archives: lectures

Calendar: club events open December

As we flip the calendar to December, there are a couple of good headline events, four astronomy club meetings, and several educational events to look forward to.

Astronaut and mountaineer Scott Parazinski is the only person ever to have both flown in space and stood on the top of Mount Everest. He’ll be at the Museum of Flight at 2 p.m. on Saturday, December 9 to talk about his experiences and his new book, The Sky Below: A True Story of Summits, Space, and Speed (Little A, 2017). Parazinski will sign copies of the book after his talk, which is free with museum admission.

If you can’t make it Saturday, you can pick up the book by clicking the link above or the book cover at left; Seattle Astronomy gets a small royalty at no cost to you when you purchase this way, and it helps support our operations. Thanks so much!

Life in Space

The Pacific Science Center’s Science in the City lecture series continues at 7 p.m. Wednesday, December 6 with a program called Life in Space. Three University of Washington astrobiologists will discuss their research—including the search for planets around other stars, characterizing how stars influence the habitability of those planets, and techniques to mix computer modeling with data analysis to determine the characteristics of potentially habitable worlds. Two of the three presenters will be familiar to Seattle Astronomy readers. Brett Morris is a PhD candidate of astronomy and astrobiology at the University of Washington and is a co-founder and co-host of the popular Astronomy on Tap Seattle events. Dr. Erika Harnett is a research associate professor and was featured on the blog and podcast this year. The “new guy” is Marshall “Moosh” Styczinski, a grad student who does research using magnetic fields to peel back the icy crust of Jupiter’s moons, looking for places that life may be found.

After viewing the documentary The Search for Life in Space, the trio will answer questions about their research and other topics addressed in the film.

Tickets to Life in Space are $5, free for Pacific Science Center members.

Astronomy club activity

Four clubs have their monthly meetings this week:

In addition, two clubs have public outreach events on Saturday. The BP Astro Kids on Bainbridge Island will make LED holiday cards during sessions at 4 p.m. and 5 p.m. at the Ritchie Observatory on Bainbridge Island. Following at 7:30 p.m. the Battle Point Astronomical Association monthly planetarium show will focus on how neutron stars make gold, and how we can tell they’re doing it. The Tacoma Astronomical Society will hold one of its public nights at 7:30 p.m. Saturday, December 9 at the Fort Steilacoom campus of Pierce College. The indoor presentation will be a viewing of the movie The Christmas Star. At both the Battle Point and Tacoma events there will be stargazing if the weather permits.

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Merging neutron stars and cool galaxies at Astronomy on Tap Seattle

One of the cool things about the Astronomy on Tap Seattle series of talks in pubs is access to scientists who are working on headline news. It happened at their October gathering at Peddler Brewing Company in Ballard. Jennifer Sobeck, a stellar astrophysicist in the Department of Astronomy at the University of Washington, was all set to give a talk titled, “A Hitchhiker’s Guide to the Galaxy: Bumming Around the Milky Way.” But a few days before the talk the news hit that LIGO and others had detected gravitational waves generated by merging neutron stars. Neutron stars are Sobeck’s thing, so the script went out the window and we learned about what happened.

Sobeck noted that neutron stars are what’s left behind when high-mass stars—around four to eight times the mass of the Sun—blow up in a supernova. Neutron stars are incredibly dense; the mass of the Sun packed into something 12 miles across. They have a crust, though light still gets through.

“Inside is just basically a soup,” Sobeck said. “It’s a hot mess.”

Everything inside is so compressed that scientists call it “degenerate.”

“There are no more atoms, there are no more molecules, those are all blown apart,” Sobeck explained. “It’s just like a soup of neutrons; there are just tons of neutrons, and the really cool thing is down in the center, they think the pressures are so high that you actually might get quarks.”

Neutron star merger animation by ESO/L. Calçada. Music: Johan B. Monell

August discovery

Scientists knew they had detected a neutron star merger rather than the sort of black-hole mergers previously spotted by LIGO because the signals are different. The interesting thing about the detection of two neutron stars merging is that we could see it visually because the event created a kilonova, like a supernova, but smaller.

“It’s a little bit less on the explosion scale,” Sobeck said. “Kilonova means that you’re able to have electromagnetic radiation across the spectrum that a whole bunch of facilites were able to monitor.”

So when LIGO and VIRGO detected the gravitational wave, with the help of the Fermi gamma ray space telescope and the ESA’s Integral gamma-ray observatory they they were able to narrow down the location of the event and tell others to look there. When the optical observations came in, the kilanova was spotted in the galaxy NGC 4993.

“This has never been done before,” Sobeck noted. The detection occurred in mid-August of this year, and by the end of the month the visual was gone.

“This kilonova explostion lasted only for a period of only 15 days,” Sobeck said.

Observations were made not just in the visual, but across the spectrum from gamma rays to radio, and more than a dozen observatories were involved in the analysis.

“You’re getting a different piece of information from all of these parts of the spectrum,” Sobeck noted. “They all helped fill in that puzzle.”

The story in the media

Where stuff comes from

Periodic table showing origin of elements in the Solar System, by CMGLee on Wikimedia Commons based on data by Jennifer Johnson, Ohio State University.

Sobeck said the press went a little overboard with headlines such as collision “creates gold” (CNN)  and “Universe-shaking announcement” (New York Times), yet it’s true that the kilonova made some gold. Sobeck showed the periodic table of elements at left (click to see it bigger), modified to show where all of the elements came from. She noted that hydrogen, helium, and a bit of lithium came from the Big Bang, the rest were made in stars. But stars can only fuse elements as heavy as iron. To get the really heavy stuff called lanthanides you need a kilanova. The emitted light tells you what’s there. If you see blue light after a kilonova, that means there’s a high concentration of silver, cadmium, and tin. If the light is more red, then platinum, gold, mercury, or lead is present.

“This particular event went from blue very, very, quickly to red, and it stayed red most of the time,” Sobeck said. “Hence, we’ve got a bunch of gold on our hands.”

“We found out that neutron-star mergers do make elements,” she said. “We were right, so huzzah!”

All kinds of galaxies

Grace Telford, a graduate student studying astronomy and data science at the UW, stuck with her original topic of “A Whirlwind Tour of Galaxies: the Tiny, the Gigantic, and Everything in Between” for the October Astronomy on Tap. She noted that there are several ways to classify galaxies:

  • Stellar mass or brightness
  • Shape
  • Star formation rate
  • Nuclear activity

Stellar mass or brightness

This is pretty straightforward.

“Basically the more stars a galaxy has, the brighter it is,” Telford noted. There’s quite a range of sizes. The Milky Way is a pretty common-sized galaxy, and it’s hard to make them bigger. The largest are around 10 times the size of the Milky Way.” Smaller galaxies are plentiful.

“A dwarf galaxy is something that is at least a hundred times less massive than our Milky Way,” Telford said, and they can go a lot smaller.

Way out at the small end of the chart are ultra faint dwarf galaxies, which can’t really be seen because they’re too faint. They can’t be detected at long distances.

A recently discovered type is called an ultra diffuse galaxy. This may be the same size as the Milky Way but have 100 times fewer stars, all held together by dark matter.

“This is an open area of research,” Telford said. “It’s hard to explain how to form these wierdo galaxies that are not very massive at all, but huge.”

Shape

The three main shapes of galaxies are elliptical, spiral, and irregular. Spirals may come with a large central bulge or a bar. Irregular galaxies tend to be small.

Star formation rate

It’s in star formation rate that galaxies really differentiate themselves, Telford said. Galaxies that emit a lot of blue light have lots of young stars and new star formation. Galaxies that look red are “quenched.” Their stars are older, and there’s little new star formation.

In between red and blue is the “green valley” of galaxies. They don’t actually emit green light, but they’re in transition from blue to red.

An interesting type is the “starburst” galaxy. These are galaxies that somehow stumble into a source of gas that wasn’t available to them before.

“They have the ability to form stars at a very high rate relative to the normal amount of star formation for a galaxy of its size,” Telford explained. “As a result, you have a lot of these massive young stars that are dying and exploding as supernovae and injecting a lot of energy into the gas.”

These objects are short-lived, they exhaust their gas in a hurry, at least in astronomical terms—in between 100 million years and a billion years.

Nuclear activity

Most galaxies have supermassive black holes, which can create jets of energy.

“Sometimes these black holes eat a lot of gas really quickly and then they blow out a whole bunch of energy,” Telford explained. These jets are nuclear activity. Galaxies with active galactic nuclei are most typically found in the green valley, though they’re in other types as well.

Telford gave a plug for Galaxy Zoo, where you can go looking for these differing types of galaxies and actually participate in citizen science.

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Visiting Vesta and Ceres

The Dawn spacecraft has found a lot of surprises at Vesta and Ceres. Debra Buczkowski
a geologist and planetary scientist at the Johns Hopkins University Applied Physics Lab, gave a talk recently at the Museum of Flight discussing some of the findings from the mission.

Buczkowski

Dr. Debra Buczkowski, a geologist and planetary scientist at the Johns Hopkins University Applied Physics Lab, spoke about the findings of the Dawn mission to Vesta and Ceres recently at the Museum of Flight. (Photo: Greg Scheiderer)

Vesta was Dawn’s first stop, entering orbit around the asteroid on July 15, 2011. Scientists expected to find volcanoes on Vesta. Buczkowski explained that this expectation traces back to meteorites found on Earth that are know to be from Vesta. These are known as HEDs: “howardite–eucrite–diogenite.” These closely resemble igneous rocks found on Earth, and those are made from volcanic activity. But the volcanoes aren’t there.

Before Dawn arrived at Vesta the Hubble Space Telescope showed that Vesta wasn’t spherical, but rather was significantly flattened out at its south pole. Scientists speculated that this was because of an enormous impact, and that proved to be correct. Dawn observed a huge impact crater, now called Rheasilvia Basin, the rim of which is almost as wide as Vesta itself.

“It really should have broken the asteroid apart,” Buczkowski said of the impact that created the basin, which has a huge central peak. Dawn also found a second impact crater, Veneneia Basin, which is almost as large.

Another surprise finding from Dawn is that Vesta is fully differentiated.

“Most of the asteroids are just kind of chunks of rock with one kind of rock all the way through,” Buczkowski explained. “Not Vesta; Vesta actually has a core, it has a mantle, and it has a crust.”

Vesta’s core is about half the diameter of the asteroid itself, about 220 kilometers.

“This is probably why Vesta did not fall apart when the Rheasilvia Basin formed, because it has this huge, massive core,” Buczkowski said.

The surface of Vesta was found to have lots of fractures, features larger that Earth’s Grand Canyon that look like faults. Buczkowski said they did a lot of computer modeling to see if an object the size of Vesta with a core the size of Vesta’s could develop fractures on the crust.

“The stresses that result from that huge impact kind of get redistributed because of the giant core,” she said of the findings. “Instead of being focused around the crater, they move to the equator and fracture at the equator. If we do this same model without the giant core, there’s no fracturing at the equator. So it’s because of the giant core that we have these huge fractures.”

Buczkowski said that was a little disappointing because they were hoping for volcanoes or magma-driven geology. While they didn’t find volcanoes, there is evidence of moving magma that didn’t break through to the surface. Rather, it pushed some of the surface upward, forming mounds.

On to Ceres

Dawn departed Vesta in September 2012 after spending about 14 months in orbit. As Dawn approached the dwarf planet Ceres there was much speculation about extremely bright spots on its surface that were found in Hubble images. Other observations had detected water vapor on Ceres. Since Ceres is relatively large but not dense, scientists were expecting to find ice. But there was more rock and less ice than anticipated. What they did find, Buczkowski said, was evidence of volcanism.

Occator crater

This image from NASA’s Dawn spacecraft shows Occator Crater on Ceres, with its signature bright areas. Dawn scientists have found that the central bright spot, which harbors the brightest material on Ceres, contains a variety of salts. (Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

“We’re not expecting magma on Ceres,” she said. “Ceres isn’t dense enough for the kind of magma that we’re used to here on Earth, made out of silicate rocks. This is something called cryomagma; it is basically ice with a little bit of rock.”

The biggest and brightest of the bright spots, named Cerealia Facula, is in the crater Occator. Many of the craters on Ceres are fractured, even on the crater floors, and the many bright spots on Ceres are associated with these fractures.

“What it’s looking like is that we’re having cryomagmatic activity underneath (Occator) crater,” Buczkowski said, “and what’s coming up out of these fractures is a pyroclastic spray, and the water, the volatiles in that, is sublimating away and all it’s leaving is the sodium carbonates.” Those are the bright spots we see all over Ceres.

Dawn also found that Ceres is covered in ammoniated phyllosilicates.

“Ammonia is interesting,” Buczkowski explained. “We don’t expect to find ammonia this close to the Sun, it’s usually something that’s found further out in thhe solar system.” They’re still studying whether Ceres may have formed further from the Sun and migrated in, or if the ammonia somehow made its way to Ceres from the outer solar system.

It turns out that Ceres had quite a few volcanoes, though most of them have now collapsed. There’s one that hasn’t, known as Ahuna Mons, that stands about five kilometers tall. It’s a cryovolcano.

“The volcano that we thought would be on Vesta is on Ceres,” Buczkowski noted. Ahuna Mons may be younger than the others, and also may collapse over time.

Like Vesta, Ceres was found to be differentiated, though only partially so.

“There’s a rocky core, there’s a volatile-rich mantle, and there’s a muddy slurry, a mud ocean” below the crust, Buczkowski said.

Dawn at Ceres and VestaCeres is now considered a dwarf planet, while Vesta still has asteroid status because of its lopsided shape from the giant impact. Buczkowski figures Vesta deserves dwarf-planet status, too. Whatever you call them, she thinks they’re fascinating to study because they’re kind of a bridge between the asteroids and rocky planets.

“These are more involved bodies than just plain, old asteroids,” Buczkowski said. “They’re not just chunks of rock floating in space. They’re actually like little mini-planets. They’ve got a lot of planet-like properties.”

Though they’re pretty small, they can teach us a lot.

“They’re interesting to us because they tell us a lot about how Earth and the other planets formed,” Buczkowski said. “Studying these little protoplanets we actually are looking back to the beginning of the solar system.”

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APOD: more than just pretty pictures

The Astronomy Picture of the Day is more than just a pretty photo. In fact, each of the featured images may well have more than a thousand words packed into it. You just need to drill down deeper into the site.

John McLaren, a NASA Solar System Ambassador and treasurer of the Seattle Astronomical Society, gave a presentation about APOD at the society’s meeting last week. He said the key to finding a wealth of information about celestial objects is dragging your eyes away from the pretty pictures long enough to notice the explanation of the photo and, more importantly, the submenu below it. McLaren uses this information when preparing presentations about astronomy for various groups.

“You can build a more complete story,” he explained. “There are good links here for education, for outreach, and home-schooling groups.”

You’ve probably noticed that the explanations of the photos use plenty of links to further information. Below the explanation there’s typically a set of “more on” links about objects or content. The real prize, though is in the index, a fully searchable listing of what’s on the APOD site.

That’s a lot of stuff. McLaren noted that the site was started by Robert Nemiroff and Jerry Bonnell when both worked at the Goddard Space Flight Center. The first posts were in June of 1995, and there have been more than eight thousand of them since. McLaren pointed out that when you look at the site, it is very 1995. There’s no flash or fancy moving menus. It’s pretty straight HTML, and the authors figured that changing things would run the risk of breaking a zillion links to APOD information.

Earth from Apollo 17

The Earth from Apollo 17
Picture Credit: NASA, Apollo 17, NSSDC

They don’t update the photos published, either. Clicking on each photo gives you the best version of it that they have. The one at left, a photo of Earth taken from Apollo 17 in 1972, was posted in the first week of APOD’s operation. When McLaren showed this photo on the big screen during his presentation, there was some laughter about its low resolution. He reminded us that in 1995 we were probably dialing in to the Internet with a 2400 baud modem, and that wouldn’t deliver the high-res goods in the manner to which we’ve become accustomed in our broadband world.

Click the “archive” link on each page and you’ll find a long scroll, day by day, of every APOD ever. The “index” link takes you to a menu of stars, galaxies, and nebulae, solar system objects, space technology, people, and the sky. Clicking on these will give you a handful of “editors’ choice” photos they consider to be the most educational on the chosen subject.

McLaren found this photo, the APOD of October 20, 2002, of the space shuttle docked with the Russian Mir space station in 1995. It made him wonder who took it. Was it the first known selfie?

Shuttle and Mir

The Space Shuttle Docked with Mir. Credit: Nikolai Budarin, Russian Space Research Institute, NASA

“Since it was the first docking, they wanted to get good information about how the two spacecraft functioned together,” McLaren explained. “So one of the Soyuz crews on Mir actually undocked their Soyuz spacecraft, did a fly-around, and observed the combination.” All of that was found by following the links on the photo page.

Astrophotographers who aspire to be published on APOD may well wish to check out its index of Messier objects. McLaren points out that many of the objects in the index are represented by numbers, not pictures.

“They don’t have photos of all the Messier objects posted yet, so if you submit a good color picture of them you may get your photo as the astronomy photo of the day,” he noted, which could lead to fame and fortune or at least bragging rights.

The search engine for the index is useful. Type in “Saturn rings” and it will find 200 items.

“There’s a wealth of information in there if you’re looking for something,” McLaren said.

So the next time you’re checking out the Astronomy Picture of the Day, remember that there’s a whole lot of knowledge lurking beneath those gorgeous photos.

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Seeing the invisible and finding aliens using polarimetry

The topic line for last week’s gathering of Astronomy on Tap Seattle was What the Hell is Polarimetry?, and it seemed that a significant portion of the audience at Peddler Brewing Company in Ballard shared the question.

UW postdocs Jamie Lomax and Kim Bott explained that when light starts from its source the oscillation of its wave—its “wiggle”—goes in all directions until an interaction with something makes it polarized.

“That just means that it’s wiggling in one direction,” Lomax noted. “There’s a preferred plane for that wiggle to happen in, and in polarimetry what we’re doing is measuring that preferred plane and we’re looking for light that has been polarized.”

“It can help you figure out the shape of things without having to resolve the object,” Bott added.

Polarimetry and massive stars

Lomax studies massive stars and has found use for polarimetry in her work. She gave a talk titled, “Seeing Invisible Circumstellar Structures.”

Jamie Lomax

Jamie Lomax

“The holy grail for us in massive star research is to be able to take a massive star at the beginning of its lifetime, figure out how massive it is,” Lomax said, “and map out what its life is going to look like and figure out what supernova it’s going to end its life as.”

“It turns out that is really hard, and it’s complicated by the fact that most massive stars are probably in binary systems,” she added. Since about two-thirds of massive stars are part of a binary system, one might expect that two-thirds of core-collapse supernovae would be from such systems.

“There’s a problem, and that is we’ve only seen maybe two or three core-collapse supernovae where we have evidence that suggests that it’s come from a binary star,” Lomax said.

Part of the problem, she said, is that we don’t yet know enough about the evolution of binary star systems.

“We can try to hammer out the details of how that mass is transferring between the two stars and when the system is losing material to try to figure out how that effects its future evolution,” Lomax said. “Once we start answering questions like that we can start to tease out why we aren’t seeing all of these binary supernovae we think we should be seeing.”

Lomax talked about the star Beta Lyrae, a binary system. The primary star in the system is losing mass that gets gobbled up by the secondary. This transfer of mass also forms a thick accretion disk of gas around the secondary—so thick light from the actual star can’t get through. There’s also evidence that there are jets shooting out of the system, but we don’t know where they are.

“These are all features that we can’t see very well,” Lomax said. “We can’t see the mass transfer stream between the two stars, we can’t see the jets.”

Here’s where polarimetry comes in. If a star is surrounded by a cloud of gas or dust that is circularly symmetrical, when the starlight interacts with that material the light becomes polarized, and the wiggles line up tangentially with the edge of the disk. If the cloud is elongated in some way, the wiggles form in a “preferred” direction.

“That preferred wiggle direction is 90 degrees from the direction of the elongation of the disk, so you can back out geometric information pretty quickly,” Lomax said. “Just by looking at how the light is wiggling I can tell you how the disc is oriented on the sky.”

Lomax figures that if you don’t do polarimetry you’re throwing out free information.

“You can see invisible things—to you—and that gives you extra information about what’s going on in different systems.”

Exoplanets and aliens

Bott’s talk was titled “The Polarizing Topics of Aliens and Habitable Planets.” She studies exoplanets and said polarimetry comes in handy.

“Stars don’t produce polarized light, which is really great if you’re trying to look at something dim like a planet,” she noted. The polarimeter will simply block out the starlight. There are then a number of things that might be spotted on the planet:

  • Glint from an ocean
  • Rayleigh scattering
  • Clouds and hazes
  • Rainbows
  • Biosignatures of gases in an atmosphere
  • Chiromolecules
Kim Bott

Kim Bott

These can help astronomers characterize a planet, judge its potential habitability, and even determine if life might already be flourishing there.

Bott said that polarimeters that are sensitive enough to study planets are a recent advance, and they’re studying big, bright planets to get the hang of it. Looking for rainbows can be revealing about liquids in the atmosphere of a planet.

“The light will bend in the droplets at a slightly different angle depending what the droplet is made out of,” Bott said, so they can tell whether its water, methane, or sulfuric acid.

“We’re trying to create these really robust models that will take into consideration polarized light from Rayleigh scattering in the atmosphere as well as from rainbows,” Bott said, “and if you have a planet where you can see the surface you’d be able to see the signature from glint as well.”

Since different substances bend light at different angles, we can also learn a lot by watching closely as planets move through their phases as they orbit their host stars.

“On Earth we have light going from air and bouncing off of H2O water,” Bott said. “That’s going to produce a maximum in polarized light at a different angle than on, say, Titan, where you have light going from a methane atmosphere and then bouncing off of a hydrocarbon ocean.”

“We can actually, in theory, tell what the ocean and atmosphere are made out of by looking at where, exactly, in the orbit we see this glint,” Bott explained.

As for aliens, life requires more complex molecules, chiromolecules, that are “wound” in a certain direction, like our own DNA. Such molecules would produce circularly polarized light, which if detected could be a sign that such molecules exist on the planet.

Astronomy on Tap Seattle is organized by graduate students in astronomy at the University of Washington. It’s next gathering is scheduled for October 30 at Peddler Brewing Company in Ballard.

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Calendar: Orbit around October

A month of space and astronomy events are on the calendar at the Museum of Flight, with three events kicking it all off this week.

Orbit Around October

Orbit Around OctoberThe museum’s space month is dubbed Orbit Around October, with new events on Saturdays during the month.

It all starts off on October 5 with Astronomy Night during the museum’s monthly Free First Thursday. There’s no admission charge between 5 p.m. and 9 p.m. Area astronomy clubs will be on hand with telescopes and information, and there will be other educational activities throughout the evening.

The museum also offers a couple of events on Saturday, October 7. A 2 p.m. presentation called “21st Century Communities in Space: The Cultural Details in Living Away From Earth” will celebrate the 60th anniversary of Sputnik, and then look forward to the future when we’ve colonized the Moon and Mars and are creating communities in space. What sort of culture will be there?

Then at 5:30 p.m. join in on a reception, lecture, and book signing with space writer Leonard David. David’s book Mars: Our Future on the Red Planet (National Geographic, 2016) is a companion to the recent Mars miniseries produced by the National Geographic Channel. Tickets to this event are $25, $20 for museum members, and must be purchased online by October 3.

Haunted Night Sky

The Pierce College Science Dome brings back the popular planetarium show Haunted Night Sky on Saturdays during October. The show, geared for kids aged 3-12, guides viewers to use their imaginations to find creatures in the night sky, build a Frankenstein satellite, and take a tour of the Sea of Serpents on the Moon, the Witch’s Head nebula, and other spooky places in the universe. Showtimes are 12:30 p.m. and 2 p.m. each Saturday, and it runs about 45 minutes. Tickets are $6 for kids—adults are free—and are available in advance online.

Astronomy clubs

A quick rundown of the regional astronomy club meetings this week:

Mark your calendar

You can scout out future astronomy events by visiting our calendar page.


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Calendar: What the heck is polarimetry?

The monthly gathering of Astronomy on Tap Seattle and a variety of star parties highlight this week’s calendar.

AOT

AOT Sept 27My Webster’s Ninth New Collegiate Dictionary defines polarimeter as “an instrument for determining the amount of polarization of light or the proportion of polarized light in a partially polarized ray.” I still don’t know what that means or why astronomers might be into polarimetry, but we’ll find out at 8 p.m. Wednesday, September 27 when Astronomy on Tap Seattle meets at Peddler Brewing Company in Ballard.

The guest speakers are both UW postdocs: Dr. Jamie Lomax will discuss her research using polarimetry to detect the almost-invisible material around stars, and Dr. Kim Bott will explain how she uses polarimetry to hunt for signs of habitable worlds.

Astronomy on Tap Seattle is organized by graduate students in astronomy at the University of Washington. The evening’s festivities include astronomy-themed trivia and fabulous prizes. It’s free, but buy beer. Bring your own chair to create custom front-row seating.

Star parties

Several star parties are on the calendar for the weekend. The Covington Community Park Star Party is scheduled for 9 p.m. Friday, September 29 at the park. The party is sponsored by Covington Parks and Recreation with support from the Seattle, Tacoma, and Boeing Employees astronomical societies.

The Seattle Astronomical Society plans its free monthly public star parties for 8 p.m. Saturday, September 30 at two locations: Green Lake in Seattle and Paramount Park in Shoreline.

Planetarium

The WSU Planetarium in Pullman offers a new program this weekend, “Astronomy 101.” The show runs at 7 p.m. Friday, September 29 and repeats at 5 p.m. Sunday, October 1. Tickets are $5 at the door, cash or check; no credit cards.

Mark your calendar

The Museum of Flight will observe Astronomy Night next Thursday, October 5 beginning at 5 p.m. Astronomy clubs from the area will be on hand with telescopes and information. It’s part of the museum’s free first Thursday offerings.

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