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, 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

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.

Astronomy on Tap takes a look at the first Pluto pics from New Horizons

Back in the olden days of 1979 I took an undergraduate course in astronomy at the University of Washington. The Voyager spacecraft had just visited Jupiter and the astronomy faculty were positively giddy about the new photos, data, and knowledge coming in from the largest planet in our solar system. The excitement is perhaps even greater as we digest the first images from New Horizons, which buzzed Pluto earlier this week and got our first really close look at what used to be the ninth planet.

“It’s discovering a new planet that we already knew existed,” said Brett Morris, a UW graduate student in astronomy, at a special Pluto-palooza version of Astronomy on Tap Seattle Wednesday evening at Bad Jimmy’s Brewing Company in Ballard.

The icy mountains of Pluto. Photo: NASA-JHUAPL-SwRI.

Morris said the biggest discovery in the first batch of close-ups of Pluto is that, in a section of the dwarf planet’s “heart,” now named “Tombaugh Regio” after its discoverer, Clyde Tombaugh, there are no craters.

“This suggests that the surface is less than 100 million years old,” Morris said. While that may seem like a long time, it’s a mere blink of an eye astronomically and geologically.

“This is really young, and that was a huge surprise,” Morris said. “This is the biggest surprise of the day. The surface must be active.”

He added that we have no idea yet how this could be happening, and that scientists didn’t expect to find such a thing.

Another interesting finding were tall mountains in that photo.

UW grad student Brett Morris talked
about the history of Pluto and the first
photos from New Horizons at
Astronomy on Tap Seattle July 15.
Photo: Greg Scheiderer.

“We believe that these mountains are water-ice mountains eleven thousand feet tall,” Morris said, explaining that ice of methane or carbon monoxide would crumble at that height, but that water ice, in a place as cold as Pluto, would be as hard as rock.

“Imagine an ice cube the size of Mt. Rainier,” Morris said. “That’s what we’re looking at.”

Pluto’s largest moon, Charon, has material at its north pole that is darker than the rest of its surface which, like Pluto’s, also appears to be active. They’ve also spotted a large canyon on Charon.

“That canyon is twice as deep as the Grand Canyon, it stretches across a significant chunk of Charon,” Morris explained. “It’s either a really big crater or a valley carved out by something.”

The small moon Hydra appears to be made entirely of ice.

“This is a 30-mile hunk of ice sitting out there orbiting Pluto,” Morris said.

The photos returned by New Horizons are far better than any images of Pluto captured by the Hubble Space Telescope.

“The Hubble Space Telescope tried really hard to give us good images of Pluto, but that’s really difficult because it’s so far away,” Morris said. The telescope was able to see bright and dark regions on Pluto, but that was about it. Hubble also was used to search the Pluto system for rings, moons, and other objects that could be a hazard to the speeding spacecraft.

“At 15 kilometers a second, if there’s a piece of rice in your way it will destroy your spacecraft,” Morris noted. Four of Pluto’s five known moons were discovered by Hubble during this process.

Morris noted that it’s going to take a while for New Horizons to send us all the data it has collected during its flyby of Pluto. The spacecraft is equipped with what he says is essentially a 200-megabyte modem that only contacts Earth every once in a while.

“This is worse than AOL!” he quipped. We should keep receiving photos and data from New Horizons through November of 2016, so we have a lot of cool new discoveries to look forward to. May we be fortunate enough to enjoy a cold brew with each one of them!