solar eclipse

All posts tagged solar eclipse

Ancient Babylonian astronomy textbook.

Today, in the first summer meeting of our research group, we discussed a recent paper from Prof. Guillermo Gonzalez of Ball State that explored observations from Babylonian clay tablets to estimate changes to the spin rate of the Earth.

Even though it seems like there’s never enough time in the day, it turns out that the Earth’s rotation rate has been slowing over thousands (and even billions) of years. Numerous effects, including tidal interactions with the Moon, reshaping of Earth via earthquakes, and the melting of glaciers, all contribute to slow down or speed up Earth’s rotation.

One good way to measure the change in the length of the day is to measure the positions of stars, planets, and the Moon in the sky and compare their positions with where you’d expect them to be based on the time. And going back to about 1600, astronomers have used telescopes to accurately measure the timing of celestial configurations to good enough precision that changes in the length of the day can be seen – for instance, the day was about 22 minutes longer when Galileo first pointed his telescope to the heavens.

But the change in length of the day is pretty small – the Moon’s tides slow the Earth about 2.3 milliseconds per day each century – and the change isn’t necessarily constant over time. Fortunately, even thousands of years of ago, humans were keeping track of the positions of objects in the sky, even though they didn’t know what the objects were.

In Gonzalez’s recent paper, he analyzes reports from ancient Babylonian astronomers of lunar occultations and appulses (i.e., close approaches). These reports extend back to 400 BC, giving an observational baseline of nearly 2500 years, and are replete with lovely and ancient descriptions:

“Year 7. Month IV, the 22nd, 64 degrees before sunrise, Saturn came out from the northern horn of the Moon.”

Gonzalez’s results mostly agree with previous work, although he finds that the Earth’s rotation has slowed a bit more slowly than other estimates suggest since the time of Babylon.

Over the Memorial Day weekend, we hosted a workshop for volunteers with the Citizen CATE Project, an ambitious citizen-science project to make a 90-min long movie of totality during the solar eclipse on August 21.

For the August eclipse, it only takes about 2-min for the Moon’s shadow to pass over anyone point on the surface of the Earth – after all, it’s traveling about 1,000 miles per hour.

But the Citizen CATE project aims to extend the duration of totality by outfitting sites all along the eclipse track with telescopes, cameras, Arduinos, etc.

That way, as the Moon’s shadow passes from west to east across the US, from one site to the next, the images can be cut together to produce a totality that lasts much longer than that at any one site. The resulting movie will quickly be uploaded to the internet and made available to eclipse-lovers the world over.

Such citizen science projects go back at least to 1715, when the preeminent Edmund Halley, of cometary fame, predicted the apparition of a solar eclipse to a precision of four minutes. He enlisted the aid of his fellow citizens to record the eclipse duration at more than a dozen locations throughout the British Isles. Compiling these data, he was able to significantly improve the Moon’s ephemeris and make much more accurate future predictions.

And so on Sunday, May 28, the Physics Dept at Boise State invited groups from sites across Idaho to campus for a training workshop hosted by Citizen CATE. The day was hot and sunny – perfect for sunburns and sungazing – and I’ve posted photos from our work below.

Jolts and Juice on the main drag in Ontario.

Last week, I spent a few days in Ontario, Oregon, our neighbor just across the border.

I was invited to visit by Sam Castonguay, a geologist at Treasure Valley Community College (TVCC) as part of my American Astronomical Society Shapely Lectureship. I was allowed to interrupt an advanced calculus class to talk with the students about the upcoming eclipse and astronomy in general. Lots of great questions and enthusiasm for science amongst the TVCC folks.

In the evening of May 31, I gave a presentation to about 70 members of the broader Ontario community about the eclipse. I was really impressed by how engaged and receptive everyone was, and I was able to address concerns folks had about this historical event. People were also very excited to receive eclipse shades.

The next day, I visited with science students at Ontario High School. Even though the semester was nearly over, the students were very attentive and asked a wide range of questions.

And finally, on Saturday, June 2, I attended Ontario’s Global Village Fest at the invite of the local Chamber of Commerce. Good audience, and the clouds that moved into that morning were thick enough to keep the temperatures bearable but thin enough that we were able to set up a to-scale demonstration of the eclipse.

Although all the events left a very positive impression of Ontario, one thing really stuck out during my visit to TVCC. The school recently received a donation of mastadon and mammoth fossils dug out of a nearby quarry. Between my visit to the calculus class and the evening presentation, Castonguay showed me these amazing bones, pictured at left. One of the best things I’ve found about this part of the country is that there are a fair number of fossil deposits throughout. TVCC is in the process of setting up a display for their fossils, and so if you’re in Ontario anytime soon, be sure to visit their collection.

This visit and many others are made possible by support from the Idaho STEM Action Center and donations to the Pony Up Campaign from lots of generous donors, including Michal Martinez, Kathryn Scott, Debra Sklenar, John Freemuth, Keith Sander, Stuart Weiser, Tamsin Clapp, Dorothy A Snowball, Russell Wolff, Luanne Tangedal, Laurie Barrera, Mary Rausch, Steven Drake, Theresa Weiland, Earnest Harper, Brian Cronin, Robert Applequist, Darrell Palmer, Gay Pool, Garretta Reynolds, Lisa Marie Howell, and many anonymous donors.

Thanks to these folks and many others, we raised more than twice what we’d originally asked for, giving us $10k to do public astronomy outreach – an unbelievable outpouring of support from our Boise State community.

I’ve posted my presentations to the community and to the high school below.

UPDATE (2017 Jun 7): Some press coverage in the local paper – http://www.argusobserver.com/news/eclipse-explained/article_805c98f6-46eb-11e7-b41e-6b1b70b6b1d7.html.


Ontario Community Presentation

 

Ontario High School Presentation

Marionberries, a product of Washington state and not of Washington DC.

Had a nice visit last night with the folks in lovely Garden Valley about an hour’s drive north of Boise at the confluence of the Middle Fork and Payette Rivers. In response to an invitation from the Chamber of Commerce, I gave a short presentation about the solar eclipse at the Crouch Community Hall. The presentation I gave is posted below.

Folks were really engaged and interested, and I was impressed by how thoughtful and forward-thinking everyone was when it came to logistics and planning for the eclipse. The Idaho Board of Tourism expects lots of people to come to Idaho, many of whom will visit or at least pass through Garden Valley, so being prepared for August 21 is key, especially for municipalities with limited resources.

After the talk, my hosts invited me to dinner at the Two Rivers Grill, where we enjoyed a pretty amazing cobbler made from marionberries, a berry I’ve only encountered after moving to the Pacific Northwest. At dinner, my hosts explained that the marionberry was developed by Oregon State University via crossbreeding between a smaller, flavorful Chehalem blackberry and a larger, better-producing Olallie blackberry in the mid-1950s.

Little Camas reservoir south of Arco

As part of our statewide eclipse tour, this week I visited the town of Arco, perched on the margin of one of the youngest extinct lava flows in the world, the Craters of the Moon National Monument and Preserve. The blocky a’a flows in Craters resembles the surface of the Moon so closely that Apollo astronauts trained there in the 1960s. Arco itself has a very interesting history as the first town in the world light entirely by nuclear power.

During my visit, I spoke with hundreds of elementary, middle, and high school students. Then in the evening, I gave a presentation to the wider Arco community. Those presentations are available below.

In addition to the conversations with the citizens of Arco (Arconoids?), I enjoyed the fried pickles at Pickle’s Place. And the drive between Boise and Arco was filled with sparkling lakes, snow-scarfed mountains, and a podcast from Radiolab. Just as Highway 20 spilled into the valley of Castle Rocks, the sunglint from the Little Camas reservoir crashed in through my windshield. It was very Idaho.

Because Arco is in the path of totality for the August eclipse, they are hosting an event for their visitors, and you can find out more about that event here – http://arcosrockincountryoutdoors.com/.


Presentation to Arco Elementary School

Presentation to Butte County High School

Presentation to Arco Community

On the morning of August 21, 2017, a total solar eclipse will be visible across the continental United States. The Moon’s shadow will also pass through Idaho, and visitors from all around the world will flock to our state.

Boise State has partnered with local libraries, astronomy clubs, and science museums to organize outreach events all over the state throughout 2017. With these partners, Boise State will host public presentations about the eclipse and provide eclipse shades for safe viewing.

You can find more information about the eclipse in Idaho at the Physics Dept’s website.

The calendar below shows the planned visits across Idaho. If you have questions, contact Prof. Brian Jackson (bjackson@boisestate.edu).

This outreach effort is supported by a grant from the Idaho STEM Action Center and by donations from the Boise State community.

To those of you who have given to our Pony Up Campaign, thanks very much. We have raised more than $3,000. We are very gratified for your very generous donations to our Eclipse Outreach project.

Thanks to you, we will have a very robust and engaging public outreach effort this summer, reaching folks from all across our state. We’ve already scheduled several of the trips, with more to come. Keep checking this space for additional details on those events.

I’m also excited to announce that we just placed our order for eclipse shades, giving us nearly 13,000 pairs in total! That’s almost 13,000 pairs of eyeballs that will be able to safely enjoy this once-in-a-lifetime event in August.

And if you haven’t donated yet, don’t worry – there’s still time to help out and get your own shades.

Once the shades come in, we’ll mail them out to qualified donors as quickly as we can. So keep an eye on your mailbox in the coming months.

And special thanks to donors Tracy Landauer, Justin McGilvery, and Robert Jahn.