Happy New Year from Seattle Astronomy!
As 2018 gets under way we take a look back at our five favorite stories from last year.
1. Total Solar Eclipse
Well, duh. We spent nearly two years previewing the greatest celestial observing experience one can have. We did some 28 posts and more than a dozen podcasts about the Great American Eclipse. Seattle Astronomy publisher Greg Scheiderer even appeared on KING-TV’s New Day Northwestto talk eclipses.
To top all of that preparation off, we had gorgeously perfect weather for the eclipse from our viewing point in Monmouth, Oregon at Western Oregon University. Check our dispatches from Monmouth.
2. Apollo exhibit at Museum of Flight
To anyone who grew up obsessed with the race to the Moon in the 1960s, the Apollo exhibit that opened in May at the Museum of Flight is about the coolest thing there is after total solar eclipses. And it’s lasted more than two minutes! This is another event that came with great anticipation. Bezos Expeditions found some actual F-1 engines that rocketed Apollo missions into space. They fished them out of the Atlantic Ocean in 2013. Some were donated to the museum in 2015—a story that made our top-five list for that year!—and the exhibit was in the works for nearly a year and a half. While the engines are a commanding centerpiece of the exhibit, there’s a ton of other cool Apollo stuff there as well. Check our podcast previewing the exhibit and article about the opening.
3. Finding ET at Pacific Science Center
The Pacific Science Center had a couple of events during 2017 that highlighted the search for extraterrestrial life. The exhibit Mission: Find Life! ran from March through September in the science center’s Portal to Current Research space. Finding life was also the subject of one of the center’s Science in the City lectures in December. UW professor Erika Harnett participated in both, and Astronomy on Tap Seattle co-founder Brett Morris spoke at the latter as well. Check our podcast with Harnett and articles about the exhibit and the lecture.
4. Astronomy on Tap Seattle
Astronomy on Tap Seattle has been putting on monthly astronomy talks for almost three years now; they debuted in March of 2015. From Bad Jimmy’s to Hilliard’s to their current home at Peddler Brewing Company, graduate students in astronomy at the University of Washington put together monthly talks by students, faculty, and visiting dignitaries. The events also include astronomy trivia, prizes, and good beer. From astronomy art to polarimetry, we got a bit of everything this year.
5. Kelly Beatty talks Pluto
The Seattle Astronomical Society always lands great keynote speakers for its annual banquet in January, and 2017 was no exception as Sky & Telescope magazine senior editor Kelly Beatty told the story of the history of Pluto. Though Pluto wasn’t discovered until 1930, Beatty noted that the hunt really dates back to the 18th century.
A trio of scientists from the University of Washington took the audience on a search for life on other planets during a recent Science in the City talk at Pacific Science Center.
Professor Erika Harnett opened the evening explaining the overall work of NASA’s Virtual Planetary Laboratory, which is headquartered at the UW.
Erika Harnett
Photo: Greg Scheiderer
“We use a variety of techniques to study planets found in our solar system and in other solar systems for their potential habitability, the potential for life developing there,” Harnett explained.
Harnett’s particular research interest is on the vanishing atmosphere of Mars. Rovers there have helped us confirm that, while the Red Planet is now cold and arid, it was once warm and had oceans and flowing rivers. It also once had a global magnetic field, but it doesn’t any more.
“At some point in Mars’s history—and we’re really having a hard time telling when—its global magnetic field disappeared, and at that point its atmosphere was fully exposed to the radiation of space,” Harnett said. “Probably at that point it started losing a large amount of its atmosphere to space and that’s when water stopped becoming stable.”
There’s lots of ice at the poles and underground on Mars, but if warmed it would go straight to vapor because of the low atmospheric pressure.
Harnett and others are working to figure out the time line for if and when Mars was habitable.
Space is big
While we’ve been to Mars robotically and may well go in person one day, Harnett noted that space is big and there aren’t that many other places to go where life might be possible. For the rest of the universe we use remote sensing.
“We train telescopes looking at a variety of wavelengths at those locations and try to see what kind of information we can read from those wavelengths of light,” she said.
We can figure out a lot even from a little bit of light. Aliens looking at Earth from afar might conclude that the blue light means lots of water. They could measure our rotation by tracking light changes. Green or brown light might mean vegetation while white would be an indicator of ice. We could use similar methods learn such things about exoplanets far away.
Life on Jupiter’s moons
Marshall “Moosh” Styczinski is a UW graduate student who said he first got interested in Jupiter after watching the movie 2001: A Space Odyssey. Jupiter is still his favorite planet.
Moosh Styczinski
Photo: Greg Scheiderer
“Its got these four big moons that are a great place to start looking if we want to find life elsewhere in the solar system,” Styczinski said. The focus is on Europa, but the other Galilean moons play a part as well.
“Io plays a surprisingly big role in both why Europa is a promising place to look, and how we study it,” Styczinski noted. Io is pockmarked with volcanoes and its surface is coated with sulfur spewed from those volcanoes. The moons are heated internally because of tidal heating and orbital heating, and not just on the rocky moons.
“Tidal heating causes friction in the interior that warms up the rocks and melts the ice from the underside,” Styczinski explained. “The ice forms a thick crust on top that acts like a blanket, keeping the water warm from the cold space outside.”
Life needs more than just water. Europa also probably has nutrients because liquid water comes into contact with hot rocks.
“Hydrothermal vents are what makes Europa an exciting place to look for life,” Styczinski said. “It has all the basic ingredients that life needs: an energy source, nutrients, water, and shelter.”
We’ve learned a lot about Europa and made models based on our observations so far, but we need more data to get a better handle on questions like the inner structure of this moon, how deep the water is, and where geysers and hydrothermal vents might be found. The Galileo probe is no more, but a couple of other missions are on the drawing boards. NASA plans to launch the Europa Clipper some time in the next decade, and the European Space Agency is scheduled to launch JUICE—Jupiter Icy Moons Explorer—in 2022.
“Both of these missions are going to visit Europa many times, and return lots of valuable measurements that can help refine our models,” Styczinski said. “Finding the right model for Europa’s interior can directly guide future missions by telling them where to go and what we might find when we get there.”
Analyzing exoplanets
We know for certain of some 2,500 exoplanets—planets orbiting stars other than our own Sun—and there are about five thousand more possibles, of which UW grad student Brett Morris, a co-founder of Astronomy on Tap Seattle, expects about 95 percent will also be confirmed as planets. Most of these have been discovered by the Kepler telescope observing a dip in the light when an exoplanet transits in front of its host star. Morris said this discovery is not really so tricky as it sounds.
Brett Morris
Photo: Greg Scheiderer
“Probably even your iPhone camera is good enough to measure the change in brightness of the Sun when something goes in front of it,” he said. “If you just measure the brightness of the star instead of actually resolving the surface and seeing things going on, you can discover planets.”
Morris said that for every exoplanet the size of Jupiter, they’re discovering two that are about the size of Neptune and a dozen that are roughly the size of Earth.
“The big surprise is that the most common type of world is one that we don’t know anything about,” Morris said. A great many exoplanets have been discovered that are somewhere between the size of Earth and Neptune, which is about four times the diameter of the home planet. Since we don’t have any of these “mystery worlds” of that size in our solar system, the first thing astronomers want to figure out is at what size point these planets are more likely to be gaseous than rocky.
“Exactly where that line is will determine how much habitable real estate there is in the universe,” Morris said, as we don’t expect anyone or anything to be living on gas planets.
Morris is looking forward to the launch of the James Webb Space Telescope, now scheduled for next year. JWST will see in infrared, and will examine spectra of light from the atmospheres of exoplanets to reveal the elements that exist there.
“What we hope to look for are oddballs,” Morris said. Earth, for example, is the oddball of our solar system. While Venus and Mars have atmospheres of mainly carbon dioxide, ours is rich with nitrogen, oxygen, and a host of trace elements.
“Life is what causes the atmosphere here to be different,” Morris said. “We might have trouble saying whether or not life is to blame if we were looking at planets in other solar systems, but we could definitely flag that one and then try to study it harder, because something interesting is going on there.”
After the talks we watched the 3-D movie The Search for Life in Space. The film is visually spectacular. One often had the notion that a moon or the Cassini spacecraft were about to land in the next seat. It’s worth a look if you get a chance. It’s showing at Pacific Science Center at least through January. Check out the trailer below.
They’re thinking a lot about extraterrestrial life these days over at the Pacific Science Center, where two new exhibits explore how scientists are working to identify far-away planets that may harbor life, and how we’re going to feed ourselves while we’re on our way to pay a visit.
The exhibit Mission: Find Life! opened up last month in the science center’s Portal to Current Research space. Erika Harnett, a University of Washington professor of Earth and Space Sciences who serves as the education and outreach lead for the UW’s Virtual Planetary Laboratory (VPL), was one of the key players in developing the content for the exhibit.
“We really wanted to connect the research being done by the Virtual Planetary Laboratory and some of the more cutting-edge science,” Harnett said.
It’s all in the biosignature
They decided to focus on examining the biosignatures of exoplanets. Harnett noted that we actually have the technology to take images of planets orbiting other stars, even though the images only amount to a pixel or two.
“From that single pixel you can actually glean quite a bit of information,” Harnett noted. “Scientists are trying to figure out if, from that, you can actually start to see if there are signatures of life on a planet, and really the initial work that they’re doing now is defining what are the signatures of life on Earth.”
The color of the light might tell you if you’re looking at ocean or continents. You might even identify the chemical components of a planet’s atmosphere or the types of molecules that are there.
Promotional material for the exhibit notes that, for finding life, “the color purple may be the key.” Harnett explained that that’s because red dwarf stars are plentiful in the universe, and they last a long time—long enough to give life plenty of time to develop. Whatever life appears would be faced with much redder light than we have here on Earth.
“Life will want to make use of it as much as possible, so it’s going to be either purple or black vegetation, instead of green, to be able to absorb as much electromagnetic radiation in the visible as possible,” Harnett said. She noted that, for the exhibit, they wanted to convey the speed of discovery—scientists verify new exoplanet discoveries practically every day. She also wanted to set expectations about what sorts of life might be found. Spoiler alert: it won’t likely be little green men like the ones on the socks Harnett wore when we spoke.
“It’s more likely that it’s going to be something like microbes or bacteria, because that’s actually what most of the life on Earth is. It’s not the most visible, but it’s the most plentiful,” she said.
Watch an exoplanet transit
One of the cool, hands-on features of the exhibit gives visitors a look at how scientists using the Kepler Space Telescope actually find exoplanets. A lighted globe represents a star, and you can spin a couple of planets around it.
“Then they have a sensor off to the side,” Harnett said—it’s actually inside a model of Kepler. “On a screen you can see the light from the star, and then as the planet transits you can see the dip” in the amount of light that arrives at the sensor.
“You get to actually play with that and explore what the change in signal associated with a planetary transit looks like,” she added.
Another interactive feature of the exhibit is a large touch screen that uses the NASA Eyes on Exoplanets program to let visitors explore planets.
Communicating science
The Mission: Find Life! exhibit is part of the VPL’s work funded by the NASA Astrobiology Institute, which requires that a portion of funds be reserved for education and public outreach. VPL has created several science-on-a-sphere shows and trained numerous graduate students to be science communication fellows.
“The Portal to Current Research project is the culminating part of our work,” Harnett said. She has been involved with the Pacific Science Center’s communication fellows program for about a decade and said she feels effective communication about science is important.
“If scientists do a better job of communicating their science there would not be quite as much mistrust of science,” she said. “Everybody needs to get out more into the community and be doing more communication and writing for the general public, as opposed to just writing the peer-reviewed articles that will go into a journal and ten people will see.”
Harnett said they’re working to line up astrobiologists to offer talks during the exhibit’s run, especially during Astrono-May at the science center. Mission: Find Life! runs through September 4, 2017 at the Pacific Science Center.
What’s for lunch?
Another new exhibit called Feeding Future Astronauts is just across the gallery from the Portal to Current Research space. Growing food in space will take a lot less energy than carrying a bunch of it along, and the exhibit highlights some of the things NASA is trying. In the test garden of the exhibit they’re growing “outredgeous” lettuce, “Tokyo bekana” cabbage, and “Red Robin” cherry tomatoes. The latter will be a challenge because tomatoes require pollination, and as far as we know there are no bees in space. ISS astronauts are experimenting with hand pollination and how it will work in microgravity. The Red Robin might be a good variety of tomato to try in your Seattle garden; the ones in the exhibit were doing great for early April with only artificial light.
