Category Archives: astronomy

A surprise discovery from Apollo 11 lunar samples

As we look back at the 50th anniversary of the Apollo 11 Moon landing, Toby Smith notes that the most interesting science that came out of the mission was a bit of a surprise. Smith, a senior lecturer in astronomy at the University of Washington, gave a talk at the most recent meeting of Astronomy on Tap Seattle.

“There’s only one reason Apollo existed—to beat the Soviet Union to the surface of the Moon,” Smith noted. Few considered the mission to be scientific. “It wasn’t fully embraced by the scientific community even in its day, even among planetary scientists.”

But they figured as long as they were there, they should do some sort of science.

“This little bit of science they did fundamentally changed how we view not only the Moon, but the Earth-Moon system and our solar system,” Smith said.

The Apollo 11 landing site, the Sea of Tranquility on the Moon, is essentially an ancient lava flow, a featureless plain of cooled volcanic rock, Smith said. Think of it like Big Island of Hawaii, except you don’t really see the solidified lava on the Moon. The surface is soft, ground down and rounded off into a soft powder by billions of years of impacts. As Neil Armstrong observed just after his first step, it has the consistency of flour. That consistency almost accidentally led to the mission’s best science.

Moon rock box
An Apollo Lunar Sample Return container on display at the Destination: Moon exhibit at the St. Louis Science Center in 2018. (Photo: Greg Scheiderer)

Armstrong spent about 15 minutes of the two-and-a-half hour Moon walk picking up rocks and putting them into a box. At the end he collected nine scoops of lunar regolith and dumped it into the Apollo Lunar Sample Return Container (a fancy NASA term for the case for rocks) as sort of a packing material so the larger rocks wouldn’t clatter around. If they’d taken any styrofoam peanuts he might have used those instead.

Naturally, when this material was brought back to Earth, the scientists looked at it, and Smith said it just might be the most studied geological sample ever.

Smith noted that the regolith is highly angular; lunar dust is sharp.

“This is not material that was broken up by being tumbled,” he said. “This is material that was broken up by being fractured by impacts.”

It’s a diverse sample. It contains basalt, breccia (material created by impacts that shatters and sometimes melts back together), and impact spheres. There was also one unusual, bright white material in the collection. It turned out to be anorthosite, which makes up about four percent of the sample.

“It represents a piece of the original crust of the Moon long since destroyed by four and a half billion years of impacts,” Smith explained. Anorthosite is an igneous rock, like basalt, that comes from the cooling of melted rock. Basalt is created when lava moves across the ground, but Smith noted that anorthosite doesn’t work that way.

“Anorthosite forms in big pools of lava, huge pools of lava, huge chambers of lava,” he said. “As these chambers of lava slowly cool over time, the anorthosite floats to the top.”

“If this was found on the Moon it must mean that at some point early in the Moon’s history it must have been almost completely molten,” Smith added. This information made scientists re-think their notions about the origins of the Moon.

“Before Apollo there was no indication that the whole, entire Moon was almost completely melted,” he said.

The leading theory about the formation of the Moon these days is that something pretty big, about the size of Mars, smacked into the early Earth, and that material flung into space by the impact eventually coalesced into the Moon. The catch is that computer simulations of this event don’t often result in a completely molten Moon. So more study is needed. The lunar samples have been under constant scrutiny for the last 50 years, and Smith says he’s interested to see what new information can be gleaned from those samples as new analytical technology is developed.

Astronomy on Tap Seattle is organized by graduate students in astronomy at the University of Washington. The next gathering is set for Wednesday, August 28, 2019 at Peddler Brewing Company in Ballard.

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Seattle is just like Mars, and other lessons from a 3-D trip

Attendees at the most recent gathering of the Seattle Astronomical Society went on an entertaining and informative 3-D trip to Mars, and learned that Seattle is just like the Red Planet.

Antonio Paris

Antonio Paris

Our tour guide was Dr. Antonio Paris, chief scientist at the Center for Planetary Science, assistant professor of astronomy and astrophysics at St. Petersburg College in Florida, and author of Mars: Your Personal 3D Journey to the Red Planet (Center for Planetary Science, 2018).

Paris said he loves Mars and expects that humans will be going there sooner than later.

“I suspect that, the way things are going, probably in about 10 to 15 years we’re going to be on Mars,” he said, adding that he doesn’t think anyone is going to go it alone.

“Mars, in my personal opinion, is going to be an international effort, both with corporations as well as the government,” Paris said.

The book was something of a spinoff of an exhibit about Mars that Paris helped put together at the Museum of Science and Industry in Tampa. The exhibit proved pretty popular, and the book seemed the next natural step. Proceeds from book sales support the work of the Center for Planetary Science.

Paris featured fantastic 3-D images of a great many Martian geological features in his presentation. While his Ph.D. is in astronomy, he’s really morphed into something of a rock hound.

“We are primarily geologists that are studying all of the geological features here on Earth,” he said, “and we’re trying to compare and contrast them with what we see on the lunar surface, what we see on Mercury, Venus, and all of the terrestrial planets.”

Paris called the process comparative planetology.

Ripples

Ripple marks such as those shown in this photo from the rover Opportunity were deposited by water moving back and forth. Image: NASA/JPL

“If I look at something here on Earth and I can determine how that thing happened,” he said, “and I see the same thing on Mars, I can deduce that the same processes have occurred, most likely.”

That caveat was included on most of his deductions, but the comparisons are pretty compelling. For example, Paris passed around a flat piece of rock with ripple marks on it that he collected in the Canyonlands in Utah. Such ripple marks are created by water moving back and forth over the rock, and the Canyonlands piece looks exactly like stuff the rovers have seen on Mars.

Paris also showed photos of rock formations made when moving or freezing water breaks up bedrock, and wears it down into small pebbles. At least, that’s how it happens on Earth.

Potholes on Mars

This set of images compares the Link outcrop of rocks on Mars with similar rocks seen on Earth. Image: NASA/JPL-Caltech/MSSS and PSI

“We call that either fragmented sidewalk or conglomerate terrain,” he said. Here in Seattle, especially after our recent cold and snowy weather, we just call it a pothole, and that’s how the Emerald City is like the Red Planet! Potholes all over the place!

Paris does a lot of rock hunting in the American southwest, which has a lot of Mars analog sites that scientists and NASA use in their Mars work. These include Moenkopi in Arizona, Canyonlands, the Mojave Desert, Death Valley, and the Flagstaff area.

The website for the Center for Planetary Science notes that Paris will make a presentation in Portland in September at a time and place not yet published. Dollars to Voodoo Doughnuts it will be with Rose City Astronomers. Stay tuned.

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Astro Biz: Moon’s Kitchen

Moon's KitchenMany businesses, products, and places have names rooted in space and astronomy. We’re featuring one periodically on Seattle Astronomy.

Today’s Astro Biz is Moon’s Kitchen Japanese restaurant. Moon’s Kitchen is on Fourth Avenue in Seattle’s Belltown Neighborhood.

Moon’s Kitchen has no official online presence that we could discover. That’s a little odd in this day and age; if there’s no website, does a place really exist? Probably so, as there’s a robust discussion of the joint on Yelp and the like, and it receives generally good reviews, though one grump called it a “glorified teriyaki place.” You can order Moon’s Kitchen dishes for delivery through Grub Hub, Uber Eats, and possibly others.

More info:

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Wow! Check out The Planets Online

There’s a great new website about our solar system that will blow your socks off! The Planets Online introduces viewers to a broad range of subjects in a unique, innovative, and entertaining way. The site naturally interweaves information on science, engineering, music, visual design, and technology—it could be a showcase for STEAM education (Science, Technology, Engineering, Arts, and Math).

Adrian Wyard

Adrian Wyard

The site is the creation of visual artist Adrian Wyard. Followers of Seattle Astronomy may recall that we wrote about Wyard’s show The Planets Live about three years ago (story here). The concept is that Wyard uses images of celestial objects to accompany and enhance classical music. He’s done it with Gustav Holst’s The Planets, Mussorgsky’s Pictures at an Exhibition, and Dvorák’s 9th Symphony.

The core of The Planets Online is a video of a performance of The Planets by the Auburn Symphony Orchestra directed by Anthony Spain and featuring the Seattle Pacific University Women’s Choir and Wyard’s visuals. This is no ordinary video, however. If you remember when we used to get our video on plastic disks, think of The Planets Online as a video loaded with special features. As the video plays, a sidebar describes the images and who created them, offers facts about the music, pulls up Wikipedia pages and other sources about the science, throws in tidbits of trivia, and more. You can switch any of these info streams on or off depending on your interests.

Here’s a little preview video of The Planets Online.

We expect you might spend a good deal of time with the site.

There are live performances of Wyard’s work coming up this spring in Florida, Virginia, and Texas. The last northwest live performances were back in April, May, and October last year. If you missed those, you can have a little fun—and learn a few things—with The Planets Online.

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Total lunar eclipse visible from Seattle

Seattle astronomy buffs are downright pessimistic about seeing celestial events, even those that happen during our good-weather months. (And we have them.) Thus in the week before the total lunar eclipse of January 20, 2019, I posted this on the Seattle Astronomy Facebook page.

Amazingly enough, at about mid-day on eclipse day the clouds actually did begin to part a little, and a check of the Seattle Clear Sky Chart revealed a prediction that we’d have just 30 percent cloud cover come eclipse hour, and that it would be downright clear late in the evening.

One learns not to trust these things, but when the full Moon actually got up above the trees and into a clear sky out back of Seattle Astronomy headquarters, I decided this was going to happen and hauled the telescope out of the basement and onto the back deck. As the eclipse began I snapped a quick photo in order to express my amazement.

I am not an astrophotographer, as people who evaluate the entries for the Seattle Astronomical Society‘s quarterly photo contest always remind me. This one was shot with my smartphone, though when using it with the telescope I find it devilishly difficult to get the proper aim through the eyepiece (must pick up one of those gadgets from Cloud Break Optics soon.) My other “astro” camera is an old Canon Powershot A530, which is pretty easy to just stick up to the eyepiece and shoot.

I used the phone to get a pretty OK, if somewhat pixellated, pic at totality, too.

Interestingly enough, I found that the color of the “blood Moon” wasn’t quite so pronounced through the telescope and camera is it was in my naked-eye view. I think the magnification diffuses the color a bit, and the camera isn’t really made for that sort of work.

Even my sweetie, who is not normally prone to looking through telescopes at night in January, or any other month, for that matter, went out quite a few times for a magnified look, and we both spent most of the eclipse watching from a warm environment inside behind the glass of the French doors.

I hope you got a chance to see the eclipse wherever you were. The next one visible in Seattle will happen in May of 2021.

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Searching for life with giant telescopes

The Kepler Space Telescope discovered more than 2,600 exoplanets—planets orbiting stars other than our Sun. Kepler used the transit method, watching for tiny dips in the amount of light coming from a star when a planet passed in front of it. After more than nine years in space, Kepler ran out of fuel last month and NASA officially ended the telescope’s science mission. The torch has been passed to a new generation of planet hunters, and experts in the field of exoplanets say we may be less than a decade away from answering one of humanity’s biggest questions: is there life somewhere besides Earth?

David Charbonneau

Harvard physics Prof. David Charbonneau gave a lecture at the UW Oct. 16. Photo: Greg Scheiderer.

“We are the special generation that for the first time in human history is going to have the technological ability—if we choose—to go and answer this great question,” said David Charbonneau, professor of astronomy at Harvard University and a member of the Kepler mission team. Charbonneau gave a lecture recently at the University of Washington, part of the Frontiers of Physics series. He suggests that when we look for an inhabited planet, we don’t confine ourselves to just finding people.

“There may be other humans out there, but I’m going to advocate that we need to create and cast the broadest net possible when we go and actually make the first search for life outside the solar system,” Charbonneau said. He noted that SETI has been listening for years with no contact so far, and other planets are too far away to visit any time soon. But we are on the verge of being able to analyze the chemical content of exoplanet atmospheres, and that can tell us if there’s life on the ground. A scientist on a distant planet looking at Earth could tell there is life here by the chemicals in our atmosphere.

“Life has radically changed the content of our atmosphere,” he said, by creating oxygen and other elements. “We’re going to try to detect life through the unintentional waste products that are produced as life goes about its business.”

News reports of discoveries often note if an exoplanet is “Earth-like,” but in reality we know little about conditions on these far-away worlds. We can accurately figure an exoplanet’s size, mass, and density, but know little else about them. Two new telescopes—one in space, one on the ground—may be able to give us the data we need to know about actual conditions on these planets.

Giant Magellan Telescope

The Giant Magellan Telescope (GMT) is being built in Chile by an international consortium, and is expected to begin science operations around 2023. The GMT will be the largest optical telescope ever constructed, with seven 8.5-meter mirrors. This huge telescope will be able to gather an enormous amount of light, enough to analyze the atmospheres of exoplanets.

James Webb Space Telescope

The James Webb Space Telescope (JWST) is a NASA project scheduled to launch in 2021. JWST will have a 6.5-meter primary mirror, and the observatory will be able to observe light in the infrared, and that’s important.

“Infrared is where all the molecules we want to study show their fingerprints,” Charbonneau said, listing oxygen, water, and methane among the molecules of interest.

He said the JWST “will revolutionize essentially all major branches of astrophysics.”

Charbonneau said we need both of the new telescopes to nail down whether an exoplanet is inhabited.

“Individually, a large ground-based telescope or the James Webb Space Telescope cannot tell us if there’s life on a planet,” he said. That’s because they’re sensitive to different molecules. The GMT could spot oxygen, which usually means life. It’s not certain, though, because oxygen could be created in other ways. The JWST could find methane, carbon monoxide, and carbon dioxide, which would put that oxygen in context, determining if it’s there because of biological activity.

“The idea is together they can get the data that will allow us to conclude that there really is life,” Charbonneau said.

TESS and MEarth

While we wait for these two observatories to be completed, astronomers are not sitting idly by. NASA’s Transiting Exoplanet Survey Satellite (TESS) is continuing the work of Kepler, using the transit method to search for more exoplanets.

“Our mission is to find hundreds of nearby small planets amenable to detailed characterization,” said Charbonneau, who is a co-investigator on the mission. TESS will survey the entire sky over a period of two years. It was launched in April, began science work in August, and found its first exoplanet in September. Charbonneau said that by December they should have the data to determine if this new exoplanet has an atmosphere.

Charbonneau is the primary investigator for the MEarth Project, which is searching for habitable exoplanets around nearby stars. MEarth consists of two automated observatories, one near Tucson, Arizona and the other in Chile. Each employs eight robotic 16-inch telescopes that constantly watch M-dwarf stars for transiting exoplanets. There are several good reasons to look at these “red dwarf” stars. They’re plentiful—there are about 240 of them within 30 light years of us, compared to just 20 G-stars like the Sun. Since they’re smaller stars and not as bright, they won’t wash out an orbiting planet’s atmosphere, making the observation technically easier.

The following time-lapse video shows the MEarth-North observatory in action.

 

The point of both TESS and MEarth is to create a good list of things for GMT and JWST to check out once they come on line.

“The search for atmospheric biomarkers such as oxygen will be humanity’s first attempt to really answer this great question about whether or not we are alone,” Charbonneau said.

You can watch the entire lecture here:

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