Equinox sunset watch, Tyson visit highlight week’s calendar

A visit from astrophysicist Neil deGrasse Tyson, the final Jacobsen Observatory open house of the year, and a seasonal sunset watch are the highlights of this week’s calendar of astro-events in the Seattle area.

Tyson, director of the Haden Planetarium in New York, narrator of the recent Cosmos television series, author, and host of the StarTalk radio show and podcast, will speak at Seattle’s Paramount Theatre on two nights this week, Wednesday, September 21 and Thursday, September 22, both at 7:30 p.m. Some tickets are still available for both appearances.

Ring in autumn

AlicesAstroInfo-145Join Alice Enevoldsen of Alice’s Astro Info at Solstice Park in West Seattle at 6:30 p.m. Thursday, September 22 to enjoy the first sunset of autumn. The equinox sunset watch will be Enevoldsen’s thirtieth such event, part of her NASA Solar System Ambassador service. The event is free, low-key, and always informative.

TJO wraps its season

Theodor Jacobsen ObservatoryThe final open house of the year is set for 8 p.m. Wednesday, September 21 at the Theodor Jacobsen Observatory on the University of Washington campus in Seattle. The talk for the evening, reservations for which are already all spoken for, will be by student Anya Raj, who has been interning with NRAO-NM over the summer and who has built a dual-dipole radio telescope. Raj will talk about amateur radio astronomy and making your own radio telescope. Volunteers from the Seattle Astronomical Society will be on hand in the observatory dome to conduct tours and, if the sky is clear, offer looks through its vintage telescope.

The popular open house series will be on hiatus for the fall and winter and will resume in April.

Club events

Seattle Astronomical SocietyThe Seattle Astronomical Society will hold its monthly meeting at 7:30 p.m. Wednesday, September 21 in room A102 of the Physics/Astronomy Building on the University of Washington campus in Seattle. Guest speaker Ethan Kruse, a graduate student in astronomy at the UW, will talk about Proxima Centauri b, the exoplanet recently found orbiting our nearest stellar neighbor. Kruse will discuss how much we know about the planet right now, and what we might learn in the coming years.

By way of preview, check our articles about a talk by Kruse at an Astronomy on Tap Seattle event from earlier this year, and about a presentation by Prof. Rory Barnes at Pacific Science Center last month exploring the potential habitability of the planet.

Tacoma Astronomical SocietyThe Tacoma Astronomical Society plans one of its public nights for 9 p.m. Saturday, September 24 at the Fort Steilacoom campus of Pierce College. The indoor presentation will be about the reasons for the seasons as we shift into fall. Weather permitting, club members will have telescopes out for looking at the sky.

Futures file

You can scout out future astronomy events on our calendar. New additions to the calendar this week include:

  • World Space Week events October 4–7 at the UW Planetarium
  • The BP Astro Kids November 12 look at the craters of the Moon

Up in the sky

The ice giants Uranus and Neptune are well-placed for observing this week. The Sky This Week from Astronomy magazine and This Week’s Sky at a Glance from Sky & Telescope offer additional observing highlights for the week.


Astro Biz: Venus Gentleman’s Club

Venus Gentleman's ClubMany businesses, products, and places have names rooted in space and astronomy. We’re featuring one every Tuesday on Seattle Astronomy.

This week’s Astro Biz is the Venus Gentleman’s Club in Wisconsin Rapids, Wisconsin. You never know when or where you’ll stumble across an Astro Biz. I discovered the Venus on a recent family-reunion trip to the city. It is right around the corner from the Square Bar, which at one time was owned by my mother’s uncle. Family lore has it that I referred to the establishment as “the drinking restaurant.” I’d accompany my dad, uncles, and grandpa there and have a root beer while they all enjoyed a brew or two. Or more.

Both the Venus as the Square Bar were closed when I went by. But I peeked into the window of the Square and it looked just as I remembered it. I even thought I recognized the well-worn Kroll elbow prints in the wood of the bar.

More info:


Proxima Centauri b and the question of habitability

The discovery of evidence of a planet in orbit around our nearest stellar neighbor, Proxima Centauri, has people all agog and with good reason. It’s something of a misnomer, however, to call the exoplanet Proxima Centauri b “Earth-like.” Rory Barnes, a professor in the Department of Astronomy and the Astrobiology Program at the University of Washington, points out that the planet’s mass is probably somewhere between 1.3 and five times that of Earth.


UW prof. Rory Barnes speaking at an Astronomy on Tap Seattle event earlier this year. Photo: Greg Scheiderer.

“There’s a lot of excitement about this planet because it is so close in mass to the Earth, but we don’t actually know if it’s even rocky like the Earth,” said Barnes during a recent talk at the Pacific Science Center. Barnes, who uses computer modeling to study the habitability of exoplanets, noted that even though Proxima Centauri is the next closest star, it’s still pretty far away at 4.24 light years. If the Sun were the size of a baseball resting on home plate at Safeco Field, Barnes said Proxima Centauri b would be a grain of sand in New York City. Still, he noted there’s understandable excitement about the discovery.

“The reason why I think that this is the biggest exoplanet discovery since the discovery of exoplanets is because it is still very close, at least relatively speaking,” Barnes said. “We really have a chance, with this planet, to potentially observe its atmosphere and its surface and maybe start to try and sniff out the presence of life on that planet. Or not. We don’t know yet. But being so close, it gives us a shot.”

Not really “like” Earth

While Proxima Centauri b is about the mass of Earth, plenty else is different. It’s twenty times closer to its home star than Earth is to the Sun, and goes around that star in just 11.2 days. We know little else about it. The star has just 12 percent of the mass and 14 percent the radius of the Sun, and its brightness is just one one-thousandth that of the Sun.

“This is a small, dim star,” Barnes said.

Is there life there?

Life requires energy, some bioessential elements, and liquid water. The energy and elements are abundant in the universe, so Barnes says the key to finding life elsewhere is liquid water.

“When we think about exoplanets, we’re really going to focus, at least for now, on surface water,” Barnes said. “Not only is it going to be easier to see, but it’s going to be more similar to the Earth and that gives us a better shot at maybe being able to interpret the observations that we’re going to get.”

The desire to find liquid surface water on a planet led us to the concept of the “habitable zone” around a star, an area where the temperature would be right for liquid water to exist. Barnes said Proxima Centauri b is smack in the middle of the habitable zone.

“This is a dream planet for those of us who study this field,” he said, but added a caveat: “Being in the habitable zone does not mean you’re habitable. It is just the first step we need to get to.”

“The habitable zone is jargon, and it’s really misleading,” Barnes added. “I apologize for my field for inflicting it on you!”

Barnes said there are several threats to habitability for planets orbiting M dwarf stars like Proxima Centauri. With the habitable zone so close to the star, there is potential that stellar flares could blow away the atmosphere of a planet within it. Planets that close are probably tidally locked, too, but this isn’t a deal-breaker; their atmospheres might distribute heat and energy effectively. Tidal heating could cause problematic volcanism.

Habitable zone chart

Barnes showed this chart demonstrating that while Proxima Centauri b is now within the habitable zone, the zone was once much further from the star.

The biggest threat to the habitability of Proxima Centauri b, according to Barnes, is that its star was once much bigger and brighter before it contracted into the dim, red phase it is in today. In the early years that would have meant that its habitable zone was out at a distance between .25 and .5 astronomical units, while Proxima Centauri b orbits at a mere .05 AU. Being so far inside the habitable zone after formation means that the planet could have lost all of its water and become a completely uninhabitable place like Venus. On the other hand, if Proxima Centauri b formed as something like Neptune, being so close to the star could have blasted away its hydrogen envelope.

“Maybe that planet could have actually transformed from an uninhabitable Neptune-like planet into a rocky planet like the Earth,” Barnes speculated. “This is what we at the University of Washington think is probably the best bet for how this planet could be habitable.”

Barnes is hopeful that the discovery of Proxima Centauri b will help boost support for the sorts of telescopes and observatories that can make the observations needed to learn more about this intriguing exoplanet and determine if it is habitable, and even inhabited.

While Barnes won’t give the odds of life there—there are way too many variables and so little we know right now—he sounds confident that we’ll find life somewhere. He noted that we’ve found life on Earth in the deep sea, extreme deserts, extreme cold, acidic environments, and under other harsh conditions.

“The realization that extreme life is everywhere is part of the astrobiological revolution that is occurring right now in science,” Barnes said. “This recognition that life finds a way gives us confidence as we go forward.”


Astro Biz: Minneapolis StarTribune

StarTribuneMany businesses, products, and places have names rooted in space and astronomy. We’re featuring one every Tuesday on Seattle Astronomy.

This week’s Astro Biz is The Minneapolis StarTribune, the major newspaper in Minneapolis, Minnesota. The Minneapolis Tribune dates back to 1867, and the Minneapolis Daily Star was founded in 1920. In the 1930s the Cowles family bought the Star and another local paper, the Journal, merging them into the Star-Journal, and in 1941 bought the Tribune as well and merged it into their company. For years the Tribune published in the morning and the Star-Journal in the evening. The arrangement lasted until 1982, when the Tribune was dropped because of low circulation, and the two papers were merged into the Star and Tribune. The name was simplified to Star Tribune in 1987, and today it goes by StarTribune.

We read the StarTribune while on a recent trip to the midwest, and get bonus points for capturing a photo of the paper on a day when the discovery of exoplanet Proxima b was front-page news!

More info:


Annual Moon viewing festival highlights week’s calendar

The last installment of the Pacific Science Center’s Science Café series and an annual Moon viewing festival are the high points of this week’s astronomy events calendar.

Viewing the Moon

Seattle Japanese GardenThe popular annual Moon Viewing Festival at the Seattle Japanese Garden will be held beginning at 6 p.m. Saturday, September 17 at the garden, which is within the Washington Park Arboretum in Seattle. The evening will include music, a haiku contest, and a traditional Japanese Tea Ceremony. Volunteers from the Seattle Astronomical Society will be on hand with telescopes to offer a great, close-up view of the Moon. Unfortunately, as of this writing the event is sold out.

Farewell to the science café

Pacific Science CenterThe Pacific Science Center is discontinuing its Science Café program after more than ten years at The Swiss Restaurant & Pub in Tacoma, Wilde Rover in Kirkland, and, up until a year or two ago, T.S. McHugh’s in Seattle. The center plans to have many of the same sorts of speakers and topics at its new, onsite Science in the City lectures.

One final astronomy-themed science café remains on the calendar and will be held at The Swiss at 6:30 p.m. Tuesday, September 13Josh Krissansen-Totton of the University of Washington Astrobiology Program and Department of Earth and Space Sciences will give a talk titled “The Search For Life Beyond Earth.” Krissansen-Totton will go beyond the headlines and explore how astronomers and astrobiologists are trying to detect life on exoplanets, and when they’re likely to be successful. Admission is free. Bring questions; there’s always plenty of time for Q-and-A.

OAS meets

Olympic Astronomical SocietyThe Olympic Astronomical Society will hold its monthly meeting at 7:30 p.m. Monday, September 12 in room Art 103 at Olympic College in Bremerton. They plan to make a comet, among other activities.

Futures file

You can scout out future astronomy events on our calendar. New additions this week include:

Up in the sky

September often offers great weather for stargazing as it’s still typically fairly warm in the evenings but the nights are getting longer. This Week’s Sky at a Glance from Sky & Telescope magazine and The Sky This Week from Astronomy have observing highlights for the week.


Astro Biz: North Star Blankets

North Star BlanketsMany businesses, products, and places have names rooted in space and astronomy. We’re featuring one every Tuesday on Seattle Astronomy.

This week’s Astro Biz is the North Star Woolen Mill in Minneapolis. The mill was built in 1864 and manufactured blankets, scarves, and other wool products until the 1940s. It was a major part of the Minneapolis economy until the company moved its operations to Ohio in 1949. The building sat vacant for nearly 50 years until it was redeveloped into lofts and condos in the late 1990s.

We found the North Star Blankets building on a recent trip to the midwest, and over the next several weeks will be featuring more spots spotted during our travels.

More info:


Labor Day week astronomy events

Happy Labor Day to all! There’s a little something on the astronomy calendar just about every night this week.

Focus on astrophotography

Tacoma Astronomical SocietyThe Tacoma Astronomical Society will hold its monthly meeting at 7:30 p.m. Tuesday, September 7 in room 175 of Thompson Hall on the University of Puget Sound campus in Tacoma. The meeting topic will be DSLR photography, with four experienced shooters and two beginners sharing their tips and challenges. The club hopes to spur wider interest in the pursuit of astrophotography.

TAS will also hold one of its public nights beginning at 9 p.m. Saturday, September 10 at the Fort Steilacoom campus of Pierce College. The indoor program will be about the Hubble Space Telescope. Club members will be on hand with scopes for public viewing, weather permitting.

Last month for Jacobsen open houses

Theodor Jacobsen ObservatoryThe second-to-last open house of the season at the University of Washington’s Theodor Jacobsen Observatory will be held at 8 p.m. Wednesday, September 7. Recent physics and astronomy graduate Evan Davis will give a talk about exoplanets. With the recent strong evidence of a planet orbiting the nearest star, Proxima Centauri, Davis’s talk is especially relevant! Reservations are recommended.

After the September 21 open house, the outreach program will go on hiatus until March.

Astronomy clubs

beaslogo_300The Boeing Employees Astronomical Society will hold its monthly meeting at 6:30 p.m. Thursday, September 8 at the Boeing “Oxbow” Recreation center. The topic or guest speaker was yet to be announced as of this writing. Non-Boeing guests are welcome, but should RSVP to Dave Ingram, contact info on the meeting link above.

Spokane Astronomical SocietyThe Spokane Astronomical Society will hold its monthly meeting at 7:30 p.m. Friday, September 9 at the Riverview Retirement Community in Spokane. The guest speaker will be Don Peckham, a member of Rose City Astronomers who has been assistant director of the club’s telescope workshop since 2005. Peckham created the String Telescope Concepts and the Tensegrity String Telescope websites. He has designed and built two truss-tube telescopes, two traditional string telescopes, and three tensegrity string telescopes.

BPAA logoSaturday will be a busy night on Bainbridge Island as the Battle Point Astronomical Association holds several events. Its BP Astro Kids programs at 5 p.m. and 6 p.m. September 10 will look at comets and help kids make their own. The planetarium program at 7:30 p.m. will take a look at cool Hubble Space Telescope images you may have missed. Observing will happen, weather permitting.

Seattle Astronomical SocietyThe Seattle Astronomical Society will hold its monthly free public star parties at 8 p.m. Saturday, September 10 at two locations: Green Lake in Seattle and Paramount Park in Shoreline. The star parties are cancelled in the event of weather unfavorable for astronomical observing. Watch the SAS website for the latest.

Above and Beyond closes

MOFIt’s your last week to check out the special exhibit Above and Beyond at the Museum of Flight. The interactive traveling exhibit celebrates both the history and future of flight through a variety of immersive simulations, interactive design challenges, impactful stories of innovation, and more. This large-scale exhibition invites you to experience what it takes to make the “impossible” possible. The last day to experience it is September 10. It’s free with museum admission.

Futures file

You can scout out future astronomy events on our calendar. New additions this week include:

  • Astronaut Mike Massimino will speak at the Museum of Flight October 14
  • Author Julian Guthrie and others will talk about the Road to SpaceShipOne at the Museum of Flight October 17
  • Physicist Rainer Weiss, a key figure in gravitational wave research, will lecture at the University of Washington October 25

Up in the sky

Spot the Moon near Saturn Thursday and Mars Friday. The Sky This Week from Astronomy magazine and This Week’s Sky at a Glance from Sky & Telescope have more observing highlights for the week.