Tag Archives: Hilliard’s Beer

The universe is big, even in small spaces

The universe is pretty vast even in confined spaces. That was the lesson given on opposite ends of the size scale at the most recent Astronomy on Tap Seattle event hosted at Hilliard’s Beer Taproom by University of Washington graduate students in astronomy.

Ethan Kruse

UW astronomy graduate student Ethan Kruse said the universe is a big place, and it will take some technological advances to reach Alpha Centauri in 20 years. Photo: Greg Scheiderer.

Grad student Ethan Kruse was all set to give a talk that concluded we would never even get out of our solar system because it is way too big. Then a few weeks before the talk Stephen Hawking and friends announced their plan for getting all the way to neighboring star Alpha Centauri in 20 years through a project called Breakthrough Starshot.

“If I’m disagreeing with Stephen Hawking,” Kruse recalled thinking, “I should probably stop for a minute and reevaluate my thesis.”

Kruse remained on point about the mind-boggling scale of the universe. He said that if our Sun was the size of a basketball sitting on the stage of Hilliard’s, Earth would be the size of a sesame seed in the back of the room, 84 feet away, and the orbiting Moon would be the size of a grain of salt. At this scale Jupiter would be a golf ball on the Ballard Bridge and Pluto would be a grain of salt about a kilometer away—about the distance to Bad Jimmy’s Brewing Company, which served as the venue for Astronomy on Tap Seattle for its first year. Alpha Centauri, in this set-up, is some 4,400 miles away—in London or Tokyo.

Kruse pointed out that the fastest spacecraft we have built so far, New Horizons, took a decade to get to Pluto.

“We went from Hilliard’s to Bad Jimmy’s in ten years,” he observed. “Don’t worry guys, we’re going to go to London in 20 years!”

The idea behind Starshot is that a super-light craft with a light sail could be accelerated by lasers to up to 20 percent of the speed of light. Kruse outlined a litany of technological challenges with the concept, including the ability to generate sufficient laser power, creating an adequately reflective material for the sails, being able to accurately aim the lasers at great distances, and shielding the craft from possible collisions with space debris. Still, he concluded, the idea is worth exploring, especially since the same technology could be used to explore the solar system more quickly.

“This is honestly the most realistic thing that anyone has proposed so far for getting to any other star system,” Kruse said.

It will, however, take a great deal of research and development.

“Don’t necessarily count on this before you die,” Kruse concluded. “Space is big.”

Jessica Werk

UW astronomy Prof. Jessica Werk says your atoms took quite a journey to become you. Photo: Greg Scheiderer.

Professor Jessica Werk, one of the newest hires onto the astronomy faculty at the University of Washington, also used sports equipment to illustrate her talk, “The History of You: The Rather Tumultuous Past of the Atoms in Your Body.” Werk pointed out that atoms are mostly empty space. If the nucleus of an atom were the size of a baseball, the nearest electrons would be a football field away.

After the Big Bang the universe was mostly light atoms: hydrogen and helium and a few others. Where did the carbon and calcium and other heavier stuff we’re made of come from?

“All evidence suggests that these atoms were fused in the cores of very, very massive stars twelve-and-a-half billion years ago,” Werk said. “Since then they have been on an absolutely crazy, long, sometimes violent journey to end up in your body 93 million miles from the Sun on this speck named Earth.”

Those atoms took a somewhat circuitous route to get here.

“Sixty percent of the atoms in your body we at one point outside of the galaxy in the circumgalactic or intergalactic medium,” Werk said. We don’t really know how they got here, but the best theory is that the atoms tend to cool off, and the gas rains back down on the galaxy, collapsing in star formation or becoming part of the debris disk out of which planets form.

There’s some mind-bending scale at the atomic level, too. Werk pointed out that there are 1023 atoms in a breath of air.

“Each breath-full of air contains more atoms than the number of breath-fulls of air in the entire Earth’s atmosphere,” she said. “What that means is that it is very likely that the last breath of air you just took contained at least one oxygen atom from the first breath of air that you ever took as a human being on planet Earth.”

That reminds us of a recent post by Ethan Siegel on the blog Starts With a Bang, in which he concluded that we all probably share atoms that were once part of King Tut or any other historical figure you might name.

AOT crowd

Astronomy on Tap Seattle outgrew Bad Jimmy’s, and pretty well packed the larger Hilliard’s at its first event there in April. Photo: Greg Scheiderer.

“The matter that makes up your physical body is part of a huge universe that is continually evolving and recycling the material in it into new forms,” Werk concluded.

The next Astronomy on Tap Seattle event is set for 7 p.m. Wednesday, May 25 at Hilliard’s. Astronomy Prof. Emily Levesque and graduate student John Ruan will give talks about some of the strangest celestial objects ever discovered or theorized. People outnumbered seats at the April event, and so the organizers suggest that you can bring a lawn chair and create your own premium seating.

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Finding exoplanets by detecting magnetospheres

Scientists are developing new and more refined ways to find and characterize exoplanets, and it involves a familiar local phenomenon. Magnetospheres of distant planets may help us spot them, and could tell us a lot about their potential for habitability.

Matt Tilley, a University of Washington graduate student working on a doctoral degree in computational space plasma physics and astrobiology, gave a talk last week titled, “The Magnetospheres of Solar System Planets and Beyond.” The lecture was part of the Pacific Science Center’s PubSci series at the Hilliard’s Beer Taproom in Ballard.

Matt Tilley

Matt Tilley discussed magnetospheres and how they might help us detect habitable exoplanets. The event was March 2 at Hilliard’s Beer Taproom in Ballard, part of the Pacific Science Center’s PubSci series. Photo: Greg Scheiderer.

Tilley explained that any planet that has a strong magnetic field will have a magnetosphere generated by the stellar wind from the star it orbits. Earth qualifies.

“The solar wind is actually an electrically charged gas that carries with it a magnetic field,” he said. “It’s an electrically charged magnetic wind blowing off of the Sun at a million miles an hour.”

The magnetosphere is essentially a bubble where the stellar wind is deflected around the planet.

“It literally is the force field for Earth, and it shields the Earth from being blasted by this electrically charged magnetic wind.”

Some recent research suggests that we may be able to spot the magnetospheres of exoplanets. To date we have found some 1,800 confirmed exoplanets, most of them by the Kepler mission which watched for slight dimming of stars which would occur as a distant planet transits the stellar disk. Usually the change in the light curve is pretty uniform, but in some cases it is not. Tilley noted that material from the stellar wind can accumulate in a bow shock at the magnetosphere, and this could be enough to show up in the Kepler data.

“If you have varying amounts of density of this electrically charged magnetic gas, this stellar wind, piled up against the bow shock, it will enter and start blocking some of the light before the planet ever enters the frame of the shot,” Tilley said.

There’s still debate about whether this is actuallly what is happening, but Tilley said it would be quite a useful discovery.

“It would be our first observation of a remote magnetic field,” he noted. “That tells us something about the composition, it tells us somethigng about the mass, the rotation rate—we can infer multiple planetary characteristics from just the magnetic field, just from this distance, this one measurement of light.”

That data, plus the existence of the magnetic field, could tell us a lot about a planet’s potential habitability.

There’s another possible way to discover exoplanets because of magnetospheres. Tilley noted that the transit method only works for edge-on systems in which the transit of planets can be detected from our vantage point. It’s extremely difficult to spot exoplanets visually because they’re so dim in contrast to their host stars. However, Tilley said that the magnetosphere generates strong signals called auroral radio emissions that shoot out from the planet’s poles. Planets generate much stronger radio waves than do stars, and so for face-on systems looking for these radio waves may well be a way to detect exoplanets.

Tilley said it’s an exciting time to be working in the field.

“Astrobiology is really the study of the conditions on a planet, the stellar conditions and the planetary conditions that make the situation right for life to form and right for it to survive long enough to evolve into something interesting,” he said.

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