Tag Archives: Julianne Dalcanton

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).

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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.

Dalcanton

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

Pillars

“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.”

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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.

Dalcanton

Dalcanton

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.

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