In Friday’s post about the approach of the solstice I cheated and just looked up the Sun’s noontime altitude using Starry Night software. But the math geek in me decided to try to dredge up my high school trigonometry nearly 40 years since studying it. I’m happy to say that I’ve still got it!
I think that the only reason I remember SohCahToa is that we had a bunch of weisenheimers in our trig class, myself included, and we came up with a report called “SohCahToa East of Java,” a joke that required that you know your geological history and late-1960s disaster movies. SohCahToh is the standard mnemonic for remembering which values to use to figure sine, cosine, and tangent.
In our problem, we’re trying to figure the angle A, that of the Sun up in the sky, given that it’s above and behind a six-foot fence casting a 14-foot shadow. Since we know the length of the opposite side, the fence, and of the adjacent side, the shadow, SohCahToa says we use tangent: Tangent=opposite/adjacent. The inverse tangent gives you the angle, in this case 23.2 degrees. (Did you know that your iPhone has a trig calculator? I didn’t until I accidentally turned mine to landscape orientation when I was calculating something much simpler a few months back. So now you can figure triangle angles and trig functions wherever you go.)
Starry Night gave the Sun’s actual altitude that day as about 19.6 degrees. The difference can be attributed to the fact that the fence is a touch shorter than six feet, and the deck is raised off the ground a few inches, making the “opposite” side even a bit shorter. Close enough, though; I was out there in my jammies with a tape-measure, and it was about 20 degrees, so I was only taking approximate measurements!
But there you go. I even showed my work. SohCahToa!
Even casual sky watchers must be noticing that the Sun is staying low in the sky all day, and that it is rising and setting way in the south. I looked down this morning and spotted a sign that the Winter Solstice is approaching in just over two weeks.
A large area of my back yard gets no direct light from the Sun because it is so low in the sky as the Solstice approaches.
An area of permafrost has formed on my deck, leftover from Monday’s blizzard that dumped nearly 1/32″ of snow in Seattle. Most of the ice is gone, except for an area in the shadow of the fence, an area that isn’t getting any direct sunlight this time of year.
Here’s where your high school geometry comes into play. The south fence is about six feet tall, and yet the shadow it is casting stretches for about 14 feet to the edge of the unmelted, unevaporated ice. A few calculations reveal that the Sun is getting less than 20 degrees above our local horizon to cast a shadow that long.
OK, I admit I just looked that up in my planetarium software, but if I remembered all of those triangle formulae I could have figured it out! Suffice to say the Sun is low in the sky, and winter is upon us.
This is one of many reasons that tomato plants prefer summer to winter. The garden bed in which our tomatoes were planted this year lies entirely inside this shadow area and is getting no Sun at all. This being Seattle, it doesn’t get so much Sun in the summer, either, but that’s another story.
You can use your astronomical knowledge anywhere! What signs have you spotted that the solstice is approaching?
Giada Arney thinks that life likely exists somewhere besides Earth. Arney, a third-year Ph.D. student in astronomy and astrobiology at the University of Washington, gave a talk at November’s meeting of the Seattle Astronomical Society about the search for the origins of life in the universe.
“Some of us like me who are astrobiologists think it’s likely that life has arisen elsewhere in the cosmos and perhaps elsewhere in our own solar system,” Arney said. “But so far the only evidence we have for life that actually exists is on this singular planet.”
Ph.D. candidate Giada Arney is planetarium coordinator at the University of Washington, and used the facility, refurbished a couple of years ago, to illustrate her talk about astrobiology. This shot of Earth was part of the talk. Photo: Greg Scheiderer.
It’s hard to extrapolate from a single data point, but Arney is on the case. The educated guess that there’s some form of life out there stems from the fact that the raw materials are all over the place. Asteroids, for example, are loaded with water and carbon molecules—and much more.
“We’ve looked at the composition of various types of very carbon-rich asteroids, and we’ve looked at the specific types of carbon molecules that exist in those asteroids,” Arney said. “We found sugars, we found amino acids—the building blocks of proteins in our cells. We found nucleic acids, the building blocks of our DNA.”
“What this suggests is that these building blocks of life are easy for nature to synthesize and they’re cosmically common,” she said.
On top of that, Arney said study of the interstellar medium reveals lots of sugars and alcohols. This had me thinking, “Well, what else do you need?!” Arney said that the significance of these is that they’re the building blocks for amino acids. Astrobiologists have yet to pinpoint amino acids in the interstellar medium—it’s exceedingly difficult to pick out their spectral fingerprints—but Arney bets they’re there.
“This suggests that this complex carbon chemistry, that at least life on Earth requires, is cosmically abundant,” she concluded.
Arney’s research bailiwick is planetary atmospheres, and that’s where astrobiologists are going to look for evidence of life on other planets. There are plenty of potential places to investigate. Arney said that around eight percent of low-mass stars have an Earth-size planet in their habitable zones. She said a recent analysis of Kepler data that put this figure at close to 20 percent came in too high because of what she feels is an overly generous definition of the zone. Even eight percent, though, gives scientists a lot of planets to explore. The ultimate test will involve direct imaging and spectroscopy of the exoplanets’ atmospheres, something we can’t really do yet.
“Once direct-imaging missions become possible, we’re going to look for gases like water vapor and oxygen in the atmospheres of exoplanets,” Arney said. “Maybe that will give us evidence for life on these planets.”
The effort will require use of another rare element: cash.
“It will be a very expensive mission because it’s going to require a very big telescope,” she said, bigger even than Hubble or Webb. “You need to collect a lot of photons in order to measure the spectra of an exoplanet to have a high enough signal-to-noise ratio to be able to confidently say, ‘Hey, there’s oxygen in this planet’s atmosphere.’”
Arney expects life is out there.
“Microbial life is probably common, but the general consensus in the astrobiology community is that complex life and certainly intelligent life is probably remarkably rare,” she concluded.
Come this time of year Seattle Astronomy often is asked for advice about good gifts for either the beginning stargazer or the avid amateur astronomer who has everything. We’ve created the Seattle Astronomy Store to make it easier than ever to shop for the Astro-minded on your list.
The question we receive most commonly is which telescope to choose for the first one. We wrote about that last year, and our advice still stands. For those new to astronomical observing, binoculars are typically a great choice. You can spot a lot with them, they’re easy to operate, and they’ll always be used even when the amateur astronomer has moved on to a big, complicated telescope.
Choosing a telescope is a bit trickier. A lot depends on one’s observing interests and circumstances. Last year’s article suggests some plausible starters, especially for kids. For the adult beginner, perhaps the best gift is The Backyard Astronomer’s Guideby Terence Dickinson and Alan Dyer. This is the volume that got me started, and it still serves as a handy reference. It’s loaded with how-tos, descriptions of the various types of telescopes and accessories, their strengths and weaknesses, and solid advice about how to pick the one that’s right for your interests. It’s a can’t-miss gift for someone new to the hobby.
Seattle-area stargazers are always happy with books as gifts, given our area’s propensity for cloud cover. One of the very best of late is Paul Bogard’s The End of Night: Searching for Natural Darkness in an Age of Artificial Light. We wrote about Bogard’s talk when he visited Town Hall Seattle in October, and have since finished the book, which was Amazon editors’ pick for best nonfiction book back in July. It’s a marvelous read, showcasing the author’s love for the beauty and mystery of the night sky as well as the health, safety, financial, ecological, and aesthetic reasons for reversing light pollution. Bogard takes us on a great trip to some of the world’s lightest and darkest places. Highly recommended.
Finally, if you’re looking for a gift for the astronomer who has everything, check our October post about Jon Bearscove’s Star Party in a Box. Bearscove, proprietor of the Galileo Astronomy Unclub, has cooked up this clever, always-ready-to-go kit that contains just about all of his stargazing essentials, save the telescope. The list of kit items, and links for purchasing them, is on that post, and it has a special section of its own in the Seattle Astronomy Store. Visit it today to find some great gift ideas for the amateur astronomers you know.
Chris Hadfield may not be quite the household name among astronauts that John Glenn, Neil Armstrong, or Buzz Aldrin are, but he tops them all in at least one category: Hadfield’s video version of the David Bowie tune “Space Oddity,” recorded on the International Space Station, has been viewed more than 19 million times on YouTube. That’s by far the most hits among his many made-from-space flicks and eclipses on-line hits on Moon-landing videos.
Though YouTube didn’t exist during the Apollo era, Hadfield said he was nonetheless inspired by the space pioneers.
“I decided to be an astronaut when I was nine; that’s when Neil and Buzz walked on the Moon,” he said. This was especially challenging for a kid from Canada. “It wasn’t just hard, it was impossible. There was no Canadian astronaut program.”
He pursued the dream anyway, learning to fly airplanes as a teen, and picking up astronaut-type skills the best he could until, finally, the opportunity presented itself.
Astronaut Chris Hadfield spoke Nov. 12 at Town Hall Seattle. Photo: Greg Scheiderer.
Hadfield didn’t talk much about the book during his Seattle event, mostly limiting prepared remarks to an account of what it’s like to be launched into space. He said the first nine minutes bring the majority of the risk on any mission.
“You have seven million pounds of thrust and you are going… somewhere!” he said. “It feels like something crashed into your spaceship. There’s this big pulse of energy through the whole ship and then a big rumbling vibration. You can’t hear it, but oh, you can feel it, like a piston in the small of your back that pushes harder and harder.”
He said that on his first space flight he experienced an unexpected injury by the time they reached orbit.
“About this time I noticed my face hurt; my cheeks were all cramped up and I realized that I’d been smiling so broadly,” Hadfield recalled.
“I laughed at myself to think that I didn’t know how much fun I was having. Part of me was going ‘OK check the pressures, check this, call out the distances, all the ranges, black zones, all the rest of it,’ and part of me was going ‘WHEEEEEE!’”
Hadfield said that playing guitar in space is an interesting experience because of weightlessness.
“When you fret with your hands, the whole guitar just takes off!” he said. ”Eventually you learn how to stabilize it.”
In addition, he said that playing with a weightless arm throws you off.
“When you try to do something quick up and down the neck you miss,” Hadfield explained. “You have to re-learn how to fret properly.”
There’s a West Coast connection to Hadfield’s space musicianship. He has a special guitar made by Roscoe Wright of Wright Guitars in Eugene, Oregon.
“He makes this really weird guitar that is just the fret board,” Hadfield said. “The guitar pieces are actually like a coat hanger, so that it gives the shape of a guitar, it feels like a guitar against your body, but it folds up really tiny, a really clever design. I got him to cut the neck in half so it would fit into a shuttle locker. He built one special for me.”
It’s not the guitar used in the “Space Oddity” video, which is an ordinary acoustic instrument.
Hadfield also fielded questions about the past and the future of space exploration. He, like most astronauts I’ve heard speak, thinks that shutting down the space shuttle program was the right call, noting that shuttles flew for the better part of three decades.
“You probably don’t drive a 30 year old car to work every day, you sure don’t drive one to space every day,” Hadfield said.
“There’s only so much money in the NASA budget, and you can’t fly an expensive vehicle while building a new vehicle unless you get a big whack of money from somebody else, and there was no somebody else,” he explained. “I think we did it just right.”
“Everybody should celebrate the space shuttle,” he added. “It was the most capable vehicle we’ve ever built and it served us superbly. I was delighted to get a chance to fly it.”
As for the future, Hadfield feels the next logical step in humanity’s continuing drive to explore will be an international effort to return to the Moon.
“We need to learn how to go live there,” he said. “We will learn an awful lot by setting up permanent habitation on the Moon over the next–who knows? 30 years, couple generations. From there hopefully we’ll invent enough things that we can go even further.”
This may not be good advice for neurosurgery or airline piloting, but it was just the ticket for identifying a mysterious, bright object in the early evening skies over Colorado Springs. While visiting family in Springs they shared with me an article in Saturday’s Colorado Springs Gazette, prompted by an email from a reader who had spotted said object for several days running and urged the paper to investigate, insisting adamantly that “it is not the planet Venus.”
Reporter Tom Roeder consulted local Navy and Air Force experts on flying things as well as an astronomer from the University of Colorado. Two of the three figured it was Venus, but demurred from making definitive statements to that effect because identifying strange, bright objects isn’t necessarily squarely within their bailiwicks.
As people who know them recognize, amateur astronomers have no such reservations. Roeder called Alan Gorski of the Colorado Springs Astronomical Society, who, after a little double checking, confirmed that the bright light is Venus, despite the assessment by the Gazette reader.
When my mother-in-law mentioned the article I, too, immediately concluded it is Venus. Readers occasionally write Seattle Astronomy with what-is-it questions, and it’s almost always either Venus or Jupiter. The King of Planets is also up in the evening these days, rising in the eastern sky a bit before 8:30 p.m. It was a nice sight shining in mostly clear skies last night.
Colorado Springs has some good potential for stargazing, as it is at just over 6,000 feet in elevation and has some pretty clear horizons, especially to the east. But alas, with a population of more than 430,000 the light pollution in the city, while not quite so bad as our home base in West Seattle, is pretty robust. The Colorado Springs Astronomical Society owns a dark-sky observing site near the town of Gardner, Colorado, a little over 100 miles south of The Springs and closest to the city of Walsenberg. The site is home to the annual Rocky Mountain Star Stare.
Astronomy clubs often hold star parties, but seasoned attendees and newcomers alike have varied expectations for such events. Jon Bearscove says that’s no wonder. He identified five different types of star party during a talk at October’s meeting of the Seattle Astronomical Society, and also suggested a common rating system so those planning to attend a star party will know what to expect.
Public astronomical observing goes back at least to Great Britain’s King George III, whom Bearscove, founder of the Galileo Astronomy Unclub, described as “a star party guy.” The definition of star party is simple: A gathering of amateur astronomers for the purpose of observing the sky. But star parties can come in a lot of different formats.
Bearscove is something of a star-party commando and knows whereof he speaks. Here are his five types:
Outreach is a common type of star party. Most astronomy clubs hold regular events to share members’ love of the night sky with others, and this is a primary mission for many. Clubs may set up a star party in a public park or even a supermarket parking lot and invite anyone who happens by to take a look through their telescopes. Outreach star parties also may be given for school groups, scout troops, or specific communities. Outreach events are highly social and are all about sharing.
Observing star parties are on the opposite end of the spectrum. These are more serious affairs for the hardcore, experienced amateur who is doing research, study, or photography. They are often held at remote locations with much darker skies. While a number of amateur astronomers may be in the same place at the same time, nobody wants to be disturbed.
President Obama’s White House Astronomy Night from 2009 qualifies as a Publicity Star Party. Jon Bearscove says you can’t do much real observing with TV lights on in one of the most light-polluted cities in the U.S. Photo: White House.
Mixed star parties are a blending of the outreach and observing types. The annual Table Mountain Star Party is an example. It’s a highly social event at which people check out everyone else’s cool astronomy gear, but there are some serious observers who attend as well. Usually those who want to be left alone can make it known. Respect those who are doing serious work; bump into someone’s telescope and you might foul up a six-hour photographic exposure.
Publicity is a new category of star party on Bearscove’s list. He describes it as an event with “no purpose” and came up with the notion when he saw photos of an Astronomy Night event held at the White House in 2009.
“If there are bright lights, media coverage, and the Secret Service, it’s a different kind of star party,” he quipped.
Literal star parties are, well, exactly that.
“Star means shiny thing in the sky; party means light, music, booze,” Bearscove said as he explained the category. His example: he once traveled to Japan for the annual Tainai Star Party, often described as the biggest in the world. Bearscove described it as more of a rock concert, with bands, bright lights, vendors, 20,000 people, and “zero observing.”
Bearscove, the shadowy figure at the bottom of the frame, explained his Star Party Intensity Scale at October’s meeting of the Seattle Astronomical Society. Photo: Greg Scheiderer.
Bearscove suggests a shorthand way of referring to star parties, inspired by the hurricane intensity scale. His three-step scale loosely corresponds to the observing, mixed, and outreach types of star parties. On the Bearscove Scale a “Category 1″ star party would feature extensive observing, “Category 2″ would have moderate intensity, and “Category 3″ would be the lowest intensity, focused on outreach.
“I think it would be neat if there could be a standard scale,” Bearscove said. “You might have people more interested in a category 2 or a category 1. Everyone’s different.”
His advice for navigating those differences: “Match star parties to your taste,” he suggested. “I like outreach a lot but I also like hard-core observing.” He crosses categories.
It will be interesting to see if the Bearscove scale catches on! Check our calendar, or visit the website of an astronomy club from our list at right, to find the date for the next star party near you.