Category Archives: lectures

Seattle Astronomy Calendar, week of April 13

A visiting author is the highlight of the week’s astronomy events, and the Moon will be involved in two interesting observing opportunities in the next seven days.

Does general relativity baffle you? Dr. Jeffrey Bennett says you’ll come away with a grasp of the concept if you attend his talk at Wednesday’s meeting of the Seattle Astronomical Society. Bennett is the author of What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter (Columbia University Press, 2014.) The meeting begins at 7:30 p.m. April 15 in room A102 of the Physics/Astronomy Building on the University of Washington campus in Seattle. Check our preview article from last week for more about Bennett and the talk.

More talks

Theodor Jacobsen ObservatoryAlso on Wednesday the UW hosts one of its bimonthly open houses at the Theodor Jacobsen Observatory. Tom Esser, a senior in the Aeronautics and Astronautics Program at the university, will give a talk titled, “The Solar System: Planets, Spacecraft, and Rockets!” It will be a jaunt through the solar system, covering the spacecraft we have sent to the planets and some of their moons, and the rockets we used to get them there. Weather permitting, visitors will be able to get a look through the observatory’s vintage telescope, operated by volunteers from the Seattle Astronomical Society. Reservations for the talk are highly recommended, as the classroom where they’re held is relatively small. The events get under way at 8 p.m. April 15 at the observatory.

Another UW student will give a talk Thursday at Town Hall Seattle. Paige Northway, a student in UW’s Earth and Space Sciences Department, looks at magnetic field measurements in space, and the critical work played by magnetometers on small satellites. Her talk begins at 6 p.m. April 16 at Town Hall. It’s part of the UW Science Now lecture series.


The Moon will be part of some interesting celestial sights this week. On Wednesday evening Neptune will be easy to find, just four degrees south of the Moon. You’ll need a telescope to spot the most distant planet. At dusk Sunday a super-thin crescent Moon bunches up with Mars and Mercury low in the western sky. Mars and Mercury are drawing closer together; they’ll be just 1.3 degrees apart by April 22.

Check This Week’s Sky at a Glance, from Sky & Telescope magazine, for other observing highlights for the week.

Yuri’s Night

LogoYurisNight_WHITEring_TRANSPARENTbackground250x250Yuri’s Night, marking the 54th anniversary of Yuri Gagarin becoming the first human in space, was last Sunday, but the celebration rolls on at Pearson Air Museum in Vancouver, Washington, which will hold a Yuri’s Night World Space Party Saturday, April 18, beginning at 5 p.m.


Bennett talk Wednesday at SAS: general relativity made easy

Dr. Jeffrey Bennett says you don’t have to have the brain of an Einstein to understand general relativity.

“If you want to deal with all the mathematics of it then it is pretty complex,” Bennett says, “but if you want to just understand it on a conceptual level, it’s not that difficult to get a general grasp of it.”

Bennett, the author of of What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter (Columbia University Press, 2014), will talk about the book, and relativity, at next week’s meeting of the Seattle Astronomical Society. The meeting, which is free and open to the public, begins at 7:30 p.m. Wednesday, April 15, in room A102 of the Physics/Astronomy Building on the campus of the University of Washington in Seattle. There’s still time to pick up the book, by clicking the link above or the cover to the left, before the talk.

Seattle Astronomy spoke earlier this week with Bennett, an adjunct research associate with the Center for Astrophysics and Space Astronomy at the University of Colorado. He says his Relativity Tour is a bit of an accident of timing. He’d been thinking about writing a book about relativity for several years. When the book came out last year it was just in time for the centennial of Einstein’s breakthrough, and Bennett decided to do his part for the International Year of Light and help the general public understand general relativity and how it makes so many everyday things possible.

Einstein was right

While Einstein proposed general relativity one hundred years ago, Bennett notes that many people still think of it as new physics, and others still strive to prove Einstein was wrong, but Bennett says that’s not going to happen.

“You can’t do that because it has checked out so much; you can’t make the evidence where it does check out go away,” Bennett explains. “In the same way, Einstein didn’t show Newton to be wrong. What you’re really looking for is to see if we can find a place where Einstein’s theory is not yet complete, and we need something else to take us to that next level.”

A good example of such a place is trying to find agreement between general relativity and quantum physics.

“That’s the known hole in our current understanding,” Bennett says. “Even though both work extremely well in the regimes in which they’ve been tested, they don’t quite meet up, and therefore there must be something else that we have not yet figured out that brings them together.”

Relativity for all audiences

Dr. Jeffrey Bennett

Dr. Jeffrey Bennett

Bennett, a recipient of the American Institute of Physics Science Communication Award in 2013, speaks to a wide variety of audiences, from adults down to elementary school kids, and has written children’s books as well as college texts.

“The commonality across all of the work that I do is that it’s all aimed at people who are not really very familiar with science and math, and in some cases, with the older audiences, maybe thinking they’re sort of afraid of these topics,” he says. “I’m always dealing on that introductory level—what science is and why you should care about it. When you’re dealing with it at that level, it’s not really that different to deal with children or with grownups, because either way you’re dealing with the same lack of knowledge and lack of understanding.”

Bennett recommends the talk he will do Wednesday for people from middle school on up, though he says younger kids often understand it as well.

“Come with an open mind,” he urges. “Even if you think this is something that you can’t understand, I think you’ll find you actually can, so I hope people will come in that spirit.”

More reading


Seattle Astronomy calendar, week of April 6

A salute to the Mercury Seven, plus a planetarium show and Yuri’s Night highlight the Seattle Astronomy calendar for this week.

Mercury Seven

The Mercury Seven. Front row L-R: Schirra, Slayton, Glenn, and Carpenter. Back row: Shepard, Grissom, Cooper. Photo: NASA.

It was 56 years ago April 9, in 1959, that NASA announced which men had been selected as the Mercury Seven, the first group of U.S. Astronauts. The seven were Scott Carpenter, Gordon Cooper, John Glenn, Gus Grissom, Wally Schirra, Alan Shepard, and Deke Slayton. The death of Carpenter in 2013 left Glenn as the only living member of the original astronaut corps.

Tom Wolfe’s book The Right Stuff is a fascinating telling of the story of the astronauts, and the 1983 movie version of the book, directed by Philip Kaufman, is fantastic as well. I still chuckle at the cast names: Ed Harris played John Glenn, Scott Glenn portrayed Alan Shepard, and Sam Shepard was cast as Chuck Yeager. There’s also a local note on the film; Seattle actress Pamela Reed portrayed Trudy Cooper, Gordo’s wife. Reed recently had a recurring role in the TV series Parks and Recreation, and was on the Seattle stage as Martha in Who’s Afraid of Virginia Woolf? at the Seattle Rep last year.

Yuri’s Night

LogoYurisNight_WHITEring_TRANSPARENTbackground250x250Sunday, April 12, marks the 54th anniversary of human spaceflight. On that date in 1961 Russian cosmonaut Yuri Gagarin became the first person launched into space. Worldwide on and around this date there are many observances of Yuri’s Night to commemorate the feat.

Only two area events are registered on the Yuri’s Night website. The Seattle Chapter of the National Space Society will meet at 7 p.m. Sunday, April 12 at the Museum of Flight, and a Yuri’s Night observance will be held next Saturday, April 18 at 5 p.m. at the Pearson Air Museum in Vancouver, Washington.

Club events

At lot of eyes were on the sky on April 11, 1986 when Halley’s Comet made its closest approach to Earth during its most recent visit to the inner solar system. Area clubs will be looking skyward this Saturday to mark the date.

The Everett Astronomical Society holds its monthly meeting at 3 p.m. April 11 at the main downtown branch of the Everett Public Library. Program details had not been announced as of this writing.

That evening beginning at 7:30 the Battle Point Astronomical Association hosts a planetarium program and evening of observing at its Edwin Ritchie Observatory in Battle Point Park on Bainbridge Island. The program topic is telescopes: the great ones of history, new ones on the drawing boards, and which one is right for you. Club members will be on hand with scopes for observing if weather permits.


General relativity explained

Cool news from the Seattle Astronomical Society, which just announced that the program for its April meeting will be a talk by Dr. Jeffrey Bennett, author of What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter (Columbia University Press, 2014).

Bennett has spent much of the last 30 years at the University of Colorado, where he remains an adjunct research associate with the Center for Astrophysics and Space Astronomy. These days he is mainly a writer and he has embarked on a “Relativity Tour” this year, celebrating the centennial of Einstein’s revolutionary ideas. Bennett’s basic premise is that general relativity is not all that difficult to grasp, and his goal is to bring relativity out of the realm of obscure science and help us understand it and the impact it has on our lives.

Oddly enough, it appears that my cats understand relativity. Followers of the Seattle Astronomy Facebook page recently saw the photo below of their demonstration. People trying to help others understand general relativity often ask them to imagine a bowling ball on a bed sheet. In this case Archie and Theodolinda used themselves as the massive objects, and the down comforter represents space-time. The green object in the background may be Neptune.

relativitycatsBennett’s explanation may not be simple enough for cats to understand, but it is advertised as suitable for anyone from middle school on up. Bennett has taught young kids, and in addition to scholarly textbooks and science tomes for adults, he has written a series of children’s books featuring the outer space adventures of Max the dog. To gear up in advance of the talk pick up What Is Relativity? by clicking this link or the photo above. Links to Bennett’s other books are below.

The Seattle Astronomical Society talk will be at 7:30 p.m. Wednesday, April 15 in room A102 in the Physics/Astronomy Building at the University of Washington in Seattle. In addition to SAS, the Relativity Tour is sponsored by Big Kid Science, Columbia University Press, Fiske Planetarium, and Story Time From Space.

More materials

Jeffrey Bennett website

Books by Bennett


Gamma ray bursts, galaxies, exoplanets, and beer

Back in 1979 when I was an undergraduate at the University of Washington I took an introductory course in astronomy to fulfill some science credit requirements. The two Voyager spacecraft had just visited Jupiter and the faculty in the astronomy department seemed practically giddy about all of the new data received and textbook re-writing to come. These days, given the number of exciting missions returning information from the near and far reaches of the solar system, it seems we’re learning something new about the cosmos almost every day.

Case in point: earlier this week a trio of UW astronomy graduate students put on the first Astronomy on Tap event in Seattle, each giving a mini-lecture about their current research. Two of them had news fresh out of the headlines.

Zapped by gamma rays

Kristen Garofali was first up with a talk titled “To GRB or Not to GRB.” The GRB in this case stands for gamma ray burst.

Astronomy on Tap

There was a full house Wednesday at Bad Jimmy’s in Ballard for the first Seattle Astronomy on Tap event. Photo by @AoTSeattle.

“Gamma ray bursts are cosmic lighthouses,” directional beams that Garofali explained result from the formation of a black hole. “When the black hole forms there are two jets of energy emitted that are really high-energy.”

Last week, for the second time in less than a year, scientists thought they had detected a GRB from our closest galactic neighbor, M31, the Andromeda galaxy. This would have been a first; we’ve never detected a GRB so nearby before. The nearest have been billions of light years distant, while M31 is a mere 2.5 million light years away from Earth.

Both the event last May and the one last week turned out not to be GRBs. Garofali noted that there are other objects out there that emit gamma rays, but these don’t look at all like whatever was detected coming from the neighborhood of M31 last week.

“It’s too bright to be a transient or an ultraluminous x-ray source,” she said. “It’s too faint, however, to be a gamma ray burst.” Even so, Garofali finds the discovery and the mystery exciting. “It could open our eyes to some new process that we haven’t thought about before,” she said.

Garofali said the reason we should care about this is that gamma rays are nasty things. At the very least, one would foul up your cell phone reception, and a strong burst could cause mass extinction on Earth. In fact, there is some scientific speculation that a GRB may well be responsible for at least one of the mass extinctions that have hit our planet. However, to do that the GRB would have to come from relatively close by and be aimed right at us. The odds of that happening are extremely long, but not zero.

Astronomy porn

Talk number two by Nell Byler was titled “Andromeda, So Fly, So PHAT.” She wasn’t using dated slang, but rather was talking about the Panchromatic Hubble Andromeda Treasury, a key tool for her work studying stellar populations. PHAT has taken up a lot of the Hubble Space Telescope’s time; the treasury was created from some 7,400 Hubble images involving 936 exposure hours. The collected data has resolved more than 117 million stars in our neighboring galaxy. The UW’s Julianne Dalcanton is the principal investigator for PHAT.


This PHAT portrait of M31 is a mosaic of more than 7,000 Hubble Space Telescope images. Photo: NASA; ESA; J. DALCANTON, B.F. WILLIAMS, AND L.C. JOHNSON/UNIV. OF WASHINGTON; THE PHAT TEAM; R. GENDLER.

Byler showed a great deal of “astronomy porn”—stunning Hubble images from the project. They’re more than just pretty pictures; Byler said PHAT has the potential to reveal much about star formation, stellar evolution, and a host of other questions about how galaxies work.

“Even though we’re looking at stars within another galaxy it provides a lot of insight for galaxies that we can’t resolve and for our own galaxy, which we think is pretty similar to Andromeda itself,” Byler said. “And there’s lots more science to be done.”

Little green men

Brett Morris closed the evening with a talk titled “Dear Grandpa.” Morris is an astrobiologist, which his grandfather thinks is a pretty fishy undertaking involving the cover-up of the existence of extraterrestrials. Morris is hoping to find ETs, though, and on the very day of Astronomy on Tap the news wires were abuzz with new information about subsurface oceans on Jupiter’s moon Ganymede and on Saturn’s moon Enceladus, both of which could be havens for life. Kenneth Chang’s article in the New York Times provides excellent coverage.

Enceladus geysers

Water vapor geysers erupt from the south pole area of Saturn’s moon Enceladus. Photo: NASA/JPL.

“Enceladus has what we call cryovolcanoes; they’re volcanos that shoot out water,” Morris said.

“I personally think that this is the best chance to look for life elsewhere in our solar system because we can send a spacecraft that just orbits this moon and picks up the water as it shoots out of the moon,” he said. “Could it get more convenient? We don’t need to dig at all!”

Morris explained how the Kepler Space Telescope hunted for planets around other stars, though he bristled a little at the fact that when one is discovered similar in size to our home world it is invariably called “Earthlike.”

“Those have very broad, flimsy definitions,” he said, noting that Venus, which is practically our twin in size and mass, could be called Earthlike, but it would not be a nice place to visit. Morris is excited for scientific advances that will help us get a better idea of what exoplanets are truly like, and to identify which ones might harbor life like us.

The Astronomy on Tap event was well attended, with more than 60 people jamming into Bad Jimmy’s Brewing Company in Ballard (which pours a lovely IPA, by the way). The talks were well received and games were enjoyed, even though our team, nicknamed “Hubble Trouble,” did not win any cupcakes donated by Trophy Cupcakes. The organizers plan to be back with more events. Follow them on Twitter at @AOTSeattle. Also watch Facebook, where they hope to set up a page soon.


An evening with famed comet hunter Don Machholz

In an age when automated programs are scanning the night sky using high-tech telescopes, CCD cameras, and computing power to find near-Earth objects, Don Machholz continues to search for comets the old-fashioned way.

“I do it visually,” Machholz explained at the annual banquet of the Seattle Astronomical Society last month. “I do not use cameras, I do not use CCDs. I look through the eyepiece and I push the telescope.”

Scheiderer and Machholz

Seattle Astronomy’s Greg Scheiderer, left, with comet hunter Don Machholz at the Seattle Astronomical Society’s annual banquet. Photo: Greg Scheiderer.

Machholz is the record holder, with eleven comets discovered visually since he started his hunt in the mid-1970s. That doesn’t sound like so many, but consider this: according to the Catalog of Comet Discoveries, there have been 1,502 comets discovered since 2005. Of those, just three have been discovered visually. The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) got full or shared credit for thirty-three comet discoveries last year alone. The last time a comet was discovered visually was in 2010, when there were two, and Machholz bagged one of those.

There’s a little bit of luck involved in comet hunting. Machholz jokes that the first thing you need to do to find a comet is to be looking where it is in the 40,000 square degrees of sky. But he has a system. He checks websites to figure out where the programs like Pan-STARRS are looking on a particular night and then conducts his hunt in a different part of the sky. Machholz divides the sky into sections, and makes telescope sweeps covering about fifteen degrees at a time. Then moves down about a half field of view and sweeps again. He keeps meticulous records of his searches.

“It sounds boring, but you get to see a different part of the sky all the time,” Machholz said.

He got interested in astronomy as a boy. His father was a naval navigator and had a book with star charts that Don used to learn the sky. When he was about eight years old his sister brought home a book about meteors that piqued his interest. Finally, Machholz received a telescope for his thirteenth birthday. On the third night out he found Saturn.

“I could see the rings on it,” he recalled, thinking stargazing might not be such a bad hobby. He was hooked.

A family tragedy helped drive Machholz’s comet-hunting program early on. In 1976 his brother, an avid skier, was killed in an avalanche. Machholz found himself depressed, with insomnia, sleeping just a few hours a night, but with lots of energy.

“That’s kind of the ideal ingredients for a comet hunter,” he said. “For the next three or four years my comet hunting program developed to a greater and greater depth. Comet hunting wasn’t just something I did, it became part of who I am.”

His early comet hunting was done from his parents’ back yard and other locations around Concord, California. After moving to San Jose in 1976 he did much of his observing from nearby Loma Prieta mountain. In 1990 he moved to Colfax, California and built an observatory there.

After so much time at the eyepiece, Machholz says his heart still skips a beat or two when he thinks he has found a new comet.

“It’s a very important moment,” he said. “First I want to remember what song was on the radio.” He always has the radio playing when he hunts, and his presentation was full of music from the Rolling Stones and the Beatles to Phil Collins and Cyndi Lauper. He adds, though, that there’s no time for jumping up and down when he finds a comet, because there’s serious work to do.

“You don’t want to lose it,” he explained. “You might have it in the field now, but if you bump the telescope or let too much time go by and it drifts out of the field, you have to be able to find it again.”

“You have to be sure you know where you’re looking, make sure it’s not a galaxy or a cluster,” he added. He double checks with his star atlas, makes a drawing that puts the comet in its position compared to the field of stars, and watches to see if it moves. If all that checks out he reports the discovery by email, phone, and fax.

96/P Machholz

Comet 96/P Machholz as seen by the HI-2 camera on the STEREO-A spacecraft.

Of all of his discoveries, Machholz said comet is 96P/Machholz is his favorite.

“It is an amazing comet; it has its own Facebook page,” he said.

The orbit of 96/P Machholz changes because of the influence of Jupiter, and the perturbations have some scientists thinking there may be large undiscovered planets way out beyond Pluto. The comet also is low on carbon and cyanogen. This hasn’t been explained, though the leading ideas are that it may have originated in another solar system, or been exposed to temperature extremes that changed its chemical composition.

It was a pleasure to spend an evening with Don Machholz. His lively presentation was full of humor and had the banquet audience laughing and engaged.


Rosetta mission: the end of the beginning

There have been a lot of amazing space missions that rank among the greatest engineering achievements of all time. The Rosetta mission has to be one of the most impressive ever. Rosetta traveled 10 years and more than four billion miles to rendezvous with comet 67P/Churyumov-Gerasimenko, a rubber-ducky-shaped pile of rocks 2.5 miles across that is zipping through space at about 84,000 miles an hour. It went into orbit around the comet and then it dropped a lander, Philae, that touched down on the surface of the comet back in November. Never mind that Philae didn’t stick the landing; that’s an quite an accomplishment.

Paul Weissman

Paul Weissman of JPL spoke about the Rosetta mission Monday at the 225th meeting of the American Astronomical Association.

Thus it was most enjoyable to hear from one of the Rosetta mission scientists, Paul Weissman of the NASA Jet Propulsion Laboratory, on Monday afternoon at the 225th meeting of the American Astronomical Society. Weissman gave a talk titled “Back to the Beginning: The Rosetta Mission to Comet Churyumov-Gerasimenko.”

“Doing space missions is a work of delayed gratification,” Weissman quipped, noting that they actually started work on Rosetta in 1996, and adding that there had been plans for such a mission for about a decade before that. They finally launched in 2004 and arrived at the comet, often shortened to C-G for obvious reasons, back in August.

“We had been ten years in space,” Weissman said. “It was really exciting to finally arrive at the comet.”

Rosetta carries 11 scientific instruments on board, and the Philae has ten. Even though Philae didn’t operate for long, between them the two craft have sent back a wealth of data.

“We’ve just been flooded with phenomenal results,” Weissman said.

Philae on C-G

Rosetta’s lander Philae on the surface of Comet 67P/Churyumov-Gerasimenko. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic. Credit: ESA/Rosetta/Philae/CIVA

He shared a great many photographs from the mission and explained what all of the instruments have been observing. Among the interesting discoveries are that C-G is spinning faster than it did on its previous trip around the Sun, the result of the forces of outgassing of the comet’s material. There are pits on the nucleus that may be sink holes or outbursts; they’re not quite sure yet. They’ve detected water within the comet, and learned it is colder in its interior than on the surface. And the comet has about 74 percent porosity.

Some of the most fantastic returns are images taken by Philae from the surface of C-G that show exquisite detail.

“We’re looking at millimeter resolution of the surface of the comet,” Weissman noted, “something that’s just astounding in terms of what we’ve been able to do previously.”

Weissman holds out hope that they’ll get more from Philae, even though its batteries are dead because it landed in the shade.

“It may be possible to re-awaken the lander in May of this year,” he noted. “The solar panels that are exposed will gather enough energy to charge up the batteries, and we might have another shot of making measurements with the lander.”

Whether that works or not, there already is a great deal of data that mission scientists simply have not yet had time to analyze, and there’s more to come.

“This is the end of the beginning,” Weissman said, “because we have another whole year that we’re going to be in orbit, studying the nucleus and watching it get active. It reaches perihelion in August, so we’ll also watch it get inactive. And there’s talk of an extended mission into 2016.”

“This is just a remarkable mission.”