Exoplanets, killer stars, and beer

Astronomers are busy trying to figure out if and when an enormous flare from the Sun might fry us—or at least zap our mobile phones—and also are looking for planets like Earth in orbit around other stars. Those were the subjects of the talks at Astronomy on Tap Seattle last week at Bad Jimmy’s Brewing Company in Ballard. The Kepler Space Telescope figured in both talks.


Rodrigo Luger spoke about the hunt for other Earths in a presentation at Astronomy on Tap 5 last week. Photo: Greg Scheiderer.

University of Washington astronomy graduate student Rodrigo Luger led off the evening’s festivities with a talk titled, “Syzygies in Silhouette: The Search for Alien Earths.” A syzygy is simply an alignment of three astronomical bodies, and when that happens we can detect a planet orbiting a distant star; the planet essentially casts its shadow on Earth, and we can measure the slight drop in brightness of the star.

Luger called Kepler “by far the most successful planet-detection mission.”

“We currently know of more than five thousand potential planetary objects around other stars, which is amazing,” Luger said, noting that, twenty years ago, we knew of maybe a couple. “It’s a fascinating time for exoplanet science.”

Luger pointed out that the number of discoveries is especially incredible when you consider that Kepler is staring at such a tiny patch of the sky.

“If there are thousands of planets (in that field), imagine how many there are in the entire Milky Way,” he marveled.

Where is Earth 2.0?

One frustration is that Kepler has yet to find an exoplanet that is a close match for Earth. Luger said planets our size are a bit tougher to tease out of the background noise that Kepler collects. That may change, he said, when NASA launches the Transiting Exoplanet Survey Satellite (TESS) in 2017.

“TESS is different; rather than looking at a tiny patch of the sky, it’s going to look at the entire sky,” Luger said.

“It’s going to focus primarily on smaller stars,” he added, noting that looking at these makes it “much easier when you want to detect Earth-like planets.”

By coincidence, the day after Luger’s talk the Kepler team announced the discovery of planet Kepler 452b, the closest match yet to Earth.

The Sun takes aim

James Davenport makes a point during his talk about solar activity. Photo: Greg Scheiderer.

James Davenport makes a point during his talk about solar activity. Photo: Greg Scheiderer.

James Davenport, who just earned his Ph.D. in astronomy at the UW, uses Kepler in his work as well. His main purpose is to better understand our own nearby star, the Sun, and figure out when it might aim a solar flare or coronal mass ejection at us.

Davenport’s talk, “How Stars Keep Active as They Age,” started with a history lesson. Back in 1859 English astronomer Richard Carrington was making daily sketches of his observations of the Sun. He was tracking a huge sunspot and, as he watched it, a couple of enormous bright patches appeared. It turns out that this was the first observation of a solar flare. About twelve hours later, people on Earth saw the most stunning aurorae in centuries.

“The sky lit up red and green, and you could see it as far south as Cuba,” Davenport said. “It was this magnificent, incredible event.” The penny dropped and scientists recognized that the solar flare was the cause of the aurora. The flare created such an electric surge that some telegraph operators suffered burns.

Don’t mess with that

“If a giant solar flare like the one that Carrington observed impacted the Earth today, it would cause trillions if not hundreds of trillions of dollars of damage,” Davenport observed, noting that TV, the Internet, and your mobile phone could get fried. “It could ruin the global economy. It would be a disaster of untold proportions, and there’s noting we can do about it. The sun is just going to hurtle these flares at us whenever it decides to.”

Davenport noted that this isn’t just an academic discussion; a flare of that magnitude barely missed Earth in July 2012.

“If it had been launched a few days earlier and it hit the Earth, we’d still be recovering,” he said.

The Sun is pretty unpredictable, Davenport said. Huge sunspots turn up about every 25 years, but there aren’t always giant flares that go with them. The good news is we’re learning more about the Sun all the time. Data from the Solar Dynamics Observatory is like an HD movie of the Sun that plays 24/7. There is always someone watching. Astronomers also are doing computer models of the Sun to try to figure out more about its processes. Kepler comes in to play by helping us look at thousands of stars of all ages. The younger ones tend to be more active, while older stars like the Sun are relatively serene. It wasn’t always that way for old Sol.

“The young Sun had bigger flares and more of them, and probably dumped out a hundred times more x-rays with every single flare,” Davenport said. “You don’t want to stand in the way of that.”

Cupcakes and beer

Mmmm. Cupcakes.

Mmmm. Cupcakes.

A lifetime of soaking up astronomical minutiae finally paid off for Seattle Astronomy at Astronomy on Tap 5 as our team, the Wild Guessers, took home top honors in both Pluto trivia contests of the evening. The prize: treats from Trophy Cupcakes decorated with images of the highly active Sun. We learned that Bad Jimmy’s strawberry mango hefeweizen goes well with cupcakes. Just watch out for the CMEs: cupcake mass ejections.

Astronomy on Tap Seattle hosts events at Bad Jimmy’s monthly. The next one is scheduled for August 26.