Tag Archives: Matt Tilley

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.


Beer and art with your astronomy

This week’s busy Seattle Astronomy calendar includes a new opportunity to mix astronomy and beer, the opening of a spacey art exhibit, and several club events.

Astronomy and beer

PubSciWe’ve been enjoying Astronomy on Tap Seattle for about a year now—in fact, it will celebrate its first birthday March 23—and now there’s another opportunity to enjoy your favorite beverage with your favorite hobby. Pacific Science Center will host one of its PubSci events at 6 p.m. Wednesday, March 2 at Hilliard’s Beer Taproom in Ballard. Matt Tilley, a Ph.D. student at the University of Washington Department of Earth and Space Sciences and Astrobiology Program, will give a talk titled, “The Magnetospheres Of Solar System Planets And Beyond.” Tilley will explain how planetary magnetic fields can be used to explore things light years away and how this matters for the search for life on exoplanets.

Hilliard’s will donate one dollar to the Pacific Science Center for every beer sold at the event, so drink up for a good cause.

Coincidentally enough, Astronomy on Tap is also held in Ballard, at Bad Jimmy’s Brewing Company. This may well make Ballard the astronomy and beer capital of the world. Or at least of Seattle.

Art on the Moon

NASA photo.

NASA photo.

An out-of-this-world art exhibit will open with a gala party at 6 p.m. Thursday, March 3 at King Street Station in Seattle. Vital 5 Productions cooked up the idea for the Giant Steps exhibition and contest to challenge students, artists, engineers, architects, designers, and other space enthusiasts to imagine and propose art projects on the surface of the Moon. The one deemed best by a panel of judges will be worth $10,000 to its creator.

Tickets to the opening are $25 and are available online. The organizers suggest your shiniest costumes, though space helmets are optional. If you can’t make the big shindig, you can see the exhibit for $10 from noon until 6 p.m. on Saturdays and Sundays during March.

Planetariums this week

Pacific Planetarium in Bremerton will present its First Friday Sky Walk show this Friday, March 4, running every half hour between 5 p.m. and 8 p.m. The show takes a look at what objects will be visible in the night sky during the month. Tickets are $3 and are available online or at the door. For those coming from the east side of the sound, the planetarium is less than a mile from the Bremerton ferry terminal.

The Willard Smith Planetarium at Pacific Science Center has a full slate of shows for a variety of ages on Saturdays and Sundays. Check their calendar, or ours, for the schedule. Planetarium shows are $3 in addition to regular Science Center admission.

Astro club events

It’s a busy week for area astronomy clubs.

The Eastside Astronomical Society will meet at 6:30 p.m. Monday, Feb. 29 at the Willard Geer Planetarium at Bellevue College. Patricia Terhune-Inverso, longtime EAS member and astronomy instructor at the college, will demonstrate how she uses the planetarium to teach her daily classes. The Eastside Astronomical Society started out as Friends of the Planetarium back in the early 1970s. Check out the interesting history article on the club’s website.

SpokaneThe monthly meeting of the Spokane Astronomical Society will be held at 7:30 p.m. Friday, March 4 in the planetarium in Science Building #28 at Spokane Falls Community College. Program details had not been published as of this writing.

The monthly meeting of the Tacoma Astronomical Society will be at 7:30 p.m. Tuesday, March 1 in room 175 of Thompson Hall at the University of Puget Sound. We didn’t have information about the program as of this writing.

taslogoTacoma also will hold one of its free public nights at 7:30 p.m. Saturday, March 5 at the Fort Steilacoom campus of Pierce College. There will be a presentation about binocular astronomy and, weather permitting, astronomers and telescopes will be ready to observe the night sky.

Up in the sky

Jupiter is nearing opposition and so now is a good time to observe the largest of the planets and its Galilean moons. The Moon passes close to Saturn on Wednesday. The Sky This Week from Astronomy magazine and This Week’s Sky at a Glance from Sky & Telescope have other observing highlights for the week.