Tag Archives: Toby Smith

Seattle Astronomy turns nine; our favorite stories of the year

We’ve been at this for nine years now! The first post on Seattle Astronomy happened January 11, 2011. It’s been a fun ride! On our birthday we’re looking back on our favorite stories of the last 12 months.

Moon landing anniversary

Apollo 11 Command Module Columbia

The big story of 2019 was the 50th anniversary of Apollo 11 and the first human landing on the Moon. We had quite a lot of activity around the anniversary. The best had to be the Destination Moon exhibit at the Museum of Flight, which included the command module Columbia that carried Neil Armstrong, Buzz Aldrin, and Michael Collins to the Moon and back. We wrote about the Seattle exhibit, and were fortunate enough to have seen it in St. Louis during the summer of 2018.

We did a series of talks about the Moon landing for Tacoma Public Libraries, reviewed Dr. David Warmflash‘s fine book Moon: An Illustrated History (Sterling, 2019), made a lunar reading list, and heard an interesting talk by UW astronomy professor Toby Smith about an almost accidental discovery from Apollo 11 that gave us new insight about the formation of the Moon.

AAS visits Seattle

Gregory Laughlin
Gregory Laughlin, astronomy professor at Yale, gave a talk about ‘Oumuamua Jan. 7, 2019 at the 233rd meeting of the American Astronomical Association, held in Seattle. Photo: Drew Dettweiler.

Every four years the American Astronomical Society meets in Seattle, and 2019 was one of those years. Our favorite session of the meeting was a talk by Yale astronomy professor Gregory Laughlin about ‘Oumuamua, the strange interstellar visitor that whizzed through our solar system in late 2018. Our article also included information from  Ka’iu Kimura, executive director of the ‘Imiloa Astronomy Center in Hilo, Hawaii, about how objects discovered by instruments on the islands are being given Hawaiian names.

We’d love to cover more such events even when they’re not held in Seattle. Your support with a subscription through Patreon can help bring that about. Please consider contributing; even a dollar a month will bring us closer to being able to support travel to events of interest to the astronomy community.

Meeting David Levy

David Levy
Seattle Astronomy’s Greg Scheiderer (left) visited with comet hunter and author David H. Levy at the Seattle Astronomical Society banquet Jan. 27, 2019.

The year started off well with a chance to chat with David Levy, author and comet discoverer who was the keynote speaker at the annual banquet of the Seattle Astronomical Society last January. Levy gave an engaging talk about his life and his love of astronomy and writing.

This year’s SAS banquet is coming up on January 25. The guest speaker will be meteorologist and astrophotographer Kerry-Ann Lecky Hepburn, who has had a number of her shots featured on Astronomy Picture of the Day.

Observing highlights

Lunar eclipse
Lunar eclipse of January 2019. Photo: Greg Scheiderer.

Our final two favorite stories of the year involve a couple of observing opportunities, one of which was successful, the other maybe only kind of so!

Back on January 20, 2019 there was a total lunar eclipse. Contrary to our usual weather in January, we got a clear evening and the eclipse was visible from Seattle. It was a good show!

The next total lunar eclipse possibly visible from Seattle will be in May of 2021.

The semi-successful observation was a try at a rare transit of Mercury across the face of the Sun on November 11, 2019. In our story we describe waiting out a possible look at the transit through insistently cloudy skies that morning. Finally there was a Sun break, just minutes before the transit was to end. I thought I caught a fleeting glimpse of Mercury just before it cleared the Sun’s disk, but then, Mercury being speedy of foot, was gone. I and a group of interested folks to gathered at Seacrest Park had fun anyway. We successfully viewed a Mercury transit from there in 2016. The next visible from Seattle won’t happen until 2049.

That’s our recap of the year. We look forward to our tenth anniversary celebration 12 months hence!

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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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