Monthly Archives: September 2015

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NASA Space Place – Measure The Moon’s Size And Distance During The Next Lunar Eclipse

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in September, 2015.

By Dr. Ethan Siegel

2013february2_spaceplaceThe moon represents perhaps the first great paradox of the night sky in all of human history. While its angular size is easy to measure with the unaided eye from any location on Earth, ranging from 29.38 arc-minutes (0.4897°) to 33.53 arc-minutes (0.5588°) as it orbits our world in an ellipse, that doesn’t tell us its physical size. From its angular size alone, the moon could just as easily be close and small as it could be distant and enormous.

But we know a few other things, even relying only on naked-eye observations. We know its phases are caused by its geometric configuration with the sun and Earth. We know that the sun must be farther away (and hence, larger) than the moon from the phenomenon of solar eclipses, where the moon passes in front of the sun, blocking its disk as seen from Earth. And we know it undergoes lunar eclipses, where the sun’s light is blocked from the moon by Earth.

Lunar eclipses provided the first evidence that Earth was round; the shape of the portion of the shadow that falls on the moon during its partial phase is an arc of a circle. In fact, once we measured the radius of Earth (first accomplished in the 3rd century B.C.E.), now known to be 6,371 km, all it takes is one assumption—that the physical size of Earth’s shadow as it falls on the moon is approximately the physical size of Earth—and we can use lunar eclipses to measure both the size of and the distance to the moon!

Simply by knowing Earth’s physical size and measuring the ratios of the angular size of its shadow and the angular size of the moon, we can determine the moon’s physical size relative to Earth. During a lunar eclipse, Earth’s shadow is about 3.5 times larger than the moon, with some slight variations dependent on the moon’s point in its orbit. Simply divide Earth’s radius by your measurement to figure out the moon’s radius!

Even with this primitive method, it’s straightforward to get a measurement for the moon’s radius that’s accurate to within 15% of the actual value: 1,738 km. Now that you’ve determined its physical size and its angular size, geometry alone enables you to determine how far away it is from Earth. A lunar eclipse is coming up on September 28th, and this supermoon eclipse will last for hours. Use the partial phases to measure the size of and distance to the moon, and see how close you can get!

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

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Image credit: Daniel Munizaga (NOAO South/CTIO EPO), using the Cerro Tololo Inter-American Observatory, of an eight-image sequence of the partial phase of a total lunar eclipse. Click for a larger view.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/

CNY Science Announcement – A Sea Change: The Premier Climate Change Event of CNY, 16 October 2015

Greetings fellow astrophiles,

The following announcement came across the CNYO internets recently for a showing of the award-winning film “A Sea Change.” The trailer is linked below and all of the additional information for the event, including the panel discussion after, is provided below.

Syracuse, NY  –  Friday, Oct 16, 7:00 pm, the award winning climate change film, A Sea Change, (aseachange.net) will be shown at The Palace Theater, 2384 James St., Syracuse.  A Sea Change premiered to a standing-room only audience at the Smithsonian Museum, and a standing ovation. The film screened at festivals in North America, Europe, and Latin America, garnering multiple awards and aired on national and international television.

A google map for directions to the Palace Theater

A Sea Change is the story of retired teacher Sven Huseby, whose love for his five-year-old grandson Elias and the world he will inherit compelled Sven, after reading an article in The New Yorker, “The Darkening Sea”  to travel thousands of miles interviewing scientists on ocean acidification – the little known flip side of global warming.

Oceans have absorbed hundreds of billions of tons of carbon dioxide (more than a quarter of all CO2 produced since the start of the Industrial Revolution) causing a 30% increase in acidification threatening all forms of sea life with a calcium-based exoskeletoncoral reefs, shell fish and tiny animals at the bottom of the food chain – pteropods. The burning of fossil fuels is fundamentally reshaping ocean chemistry.

The photography is stunning; the interviews with scientists sobering; Sven’s relationship with his grandson Elias is delightful and moving and the ending hopeful – focusing on solutions being implemented today.  This is a film you want to see if you care about the world you will leave for the next generation.

Immediately following the film there will be Q & A session. The panel consists of Barbara Ettinger,  documentary film maker; Sven Huseby, the main protagonist in the film and Dr. Bruce Monger, climate scientist from Cornell University.  Moderating the panel will be Chris Bolt, WAER news and public affairs director.

Program

5:15 Doors to Palace Theater, food trucks and vendor tables open.
6:15 Symphoria cellist Lindsay Groves welcomes the Sea Change audience to the Palace.
6:45 Program starts
7:00 Movie starts
8:30 Q&A
9:10 Program ends

Ticket prices: (suggested donations) At the door: $10 adults, $8 seniors/students, $6 per family member (seniors age 60+, families consist of at least 1 parent and children under 18 years old).

Advance sale tickets: $8 adults, $5 per senior/student/family member (seniors age 60+, families consist of at least 1 parent and children under 18 years old).

Advance sale tickets available at www.greeningusa.org/aseachange can be picked up at the door and will be held up to 15 minutes prior to the start of the film program.

Green and energy-related nonprofit organizations working on efforts to reduce greenhouse gas emissions will be staffing display tables in the lobby prior to and after the film along with companies that provide products that help mitigate climate change, such as solar panels, geothermal systems.

The event is family-friendly and film goers can attend straight from work as food trucks will be parked outside along with electric and hybrid cars on display. A cash bar and soft drinks will be available inside. Free parking available.

A special thanks goes to presenting sponsor GreeningUSA (www.greeningusa.org) and partner Syracuse International Film Festival (http://www.filminsyracuse.com).

Panelists

Barbara Ettinger – Director and Co-producer of A Sea Change. Her  first film, Martha and Ethel, was screened at the Sundance Film Festival and distributed theatrically by Sony Pictures Classics. Her most recent film, Two Square Miles, aired nationally on PBS’s Independent Lens in 2006 and 2007.

Sven Huseby – main protagonist in A Sea Change & Co-Producer is a retired independent school head who worked as a teacher and administrator at The Putney School, Vt. for 30 years and currently serves on the board of several environmental organizations. He will be attending the upcoming United Nations Climate Change Conference in Paris, Dec. 2015 with the Consultative Group on Biological Diversity.

Bruce Monger – Dr. Monger is a Senior Researcher and Lecturer in the Dept. of Earth and Atmospheric Sciences at Cornell University since 1997.  He previously worked at NASA Goddard Space Flight Center. His work has taken him world wide – to  oceanographic conferences in Denmark, Holland & Monaco and providing training for national agencies in Thailand & Argentina. In 2014 his course on Introductory Oceanography at Cornell  was featured in a NYT article as one of the top ten interesting courses in the U.S.

For information on how to support the work of the Climate Change Awareness and Action Committee, the organizing committee for this event contact pwirth2@verizon.net, 315-637-0331.

Prepping For International Observe The Moon Night (Sept. 19) And A Total Lunar Eclipse (Sept. 27)

UPDATE: 19 Sept 2015, 5:00 p.m. – Sadly, the weather is not cooperating with us this evening, so our IOMN session downtown in CANCELED. We’ll hope for better conditions during the lunar eclipse next week.

UPDATE: Meetup.com and Facebook Events have been added for both the IOMN (meetup | facebook) and eclipse IOMN (meetup | facebook) sessions.

Greetings fellow astrophiles!

We focus on the Moon this month with one natural event and one “nature-derived” (sounds better than “artificial”) event.

International Observe The Moon Night – Saturday, Sept. 19th, 7 – 9 p.m.

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It’s the Moon, so doesn’t much matter where you set up to observe. A snapshot from last year’s CNYO IOMN session in Armory Square (near The MOST and Sound Garden).

International Observe the Moon Night (InOMN) is an annual event that is dedicated to encouraging people to ‘look up’ and take notice of our nearest neighbor, the Moon. From looking at the Moon with a naked eye to using the most sensitive telescope, every year on the same day, people from around the world hold events and activities that celebrate our Moon. On this site, you can find information about an InOMN event near you or register your own event. We encourage everyone to join us in the celebration!

Because the viewing was easier (and the crowd a little easier to find) from close to The MOST last year, we’re going to set up the scopes at (or close to) the very beginning of the south end of the Onondaga Creekwalk (map below, right below The Sound Garden). This spot provides ample parking and a fairly clear view of the Southwest/South/Southeast (certainly enough for lunar viewing) while not being quite as bright as other spots in the vicinity.

2014august28_logo_finalThe 6 day old waxing crescent Moon is a nice compromise of brightness and detail for giving the Moon a good looking at (given the preference to have IOMN on a Saturday night, anyway). Not only will we have a terminator to give us shadows and perceived depth, but we’ll have pleasant views of the many large “seas” on the Moon’s surface – including Mare Tranquillitatis (with the Apollo 11 landing site just on its coast), Fecunditatis, Serenitatis, and Crisium – out in the open for inspection. For those wondering about the timing (besides the whole weekend thing), Full Moon is actually one of the most boring times to observe the Moon. With the Sun’s light beating straight down on the Moon’s surface, we have no shadows to bring out crater depth or mountain height. Most observers agree that the most interesting views are right along the terminator where light and dark meet, so having a nice piece of that to observe makes for a much more visually appealing session.

Total Lunar Eclipse – Sunday, Sept. 27th, 8:11 p.m. to 1:22 a.m. (28th)

NOTE: Bob Piekiel will be hosting a total lunar eclipse session at Baltimore Woods on the 27th. If you want to see the Moon in fine detail through telescopes, this will be an excellent place to be.

Those who’ve been keeping constant track may recognize the eclipse discussion below as a re-post from April, 2014 (Total Lunar Eclipse, Mars Just Past Opposition And A Very Early Observing Event At Baltimore Woods on April 15th), itself followed up by another lunar eclipse post from October, 2014 (CNYO Observing Log: Lunar Eclipse And Syracuse Academy Of Science, 8 October 2014).

And now onto the upcoming total eclipse – and my continued belief that lunar eclipses don’t get the respect they deserve. Yes, solar eclipses are much more exciting and it has been well-documented that people have previously responded very strongly (and not always pleasantly) to solar eclipses. The sudden darkening of the sky and noticeable temperature drop can cause all shades of responses (no pun intended) in people. That said, all we really get (besides a view of the solar corona) is an example of what happens when you put a black disc in front of the Sun. Lunar eclipses, on the other hand, tell us a bit about how the Earth itself interacts with the Sun by how this interaction alters our view of the Moon.

Both solar and lunar eclipses tell us something about the Sun/Earth/Moon relationship. Specifically, we learn that the Sun/Earth orbital plane (the oval made as the Earth goes around the Sun each year) and the Earth/Moon orbital plane (our local oval) are not the same – the Earth/Moon plane is tilted slightly off the Sun/Earth plane by 5.2 degrees (small, but just enough). That is, the Moon spends some time above and some times below the Sun/Earth orbital plane, while sitting right in the plane only two times each orbit (where the two planes intersect). How do we know this? Simple. If the Earth/Moon plane were exactly in the Sun/Earth plane, there would be a total solar eclipse and total lunar eclipse every month because there would be a time each month (New Moon) when the Sun, Moon, and Earth made a straight line (Sun-Moon-Earth = solar eclipse) and a time each month (Full Moon) when the Sun, Earth, and Moon made a straight line (Sun-Earth-Moon = lunar eclipse). As the two planes are slightly off, the New Moon is simply “off the radar” of most people because it can’t be seen during the daytime. The Full Moon, on the other hand, is brilliantly bright most of the time because it only infrequently enters the Earth’s shadow.

The image below shows this very nicely (and it’s always better to find and cite a good image than to have to roll your own). Give it a look for 30 seconds to make sure each of the four cases make sense to you.

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The Sun/Earth and Earth/Moon orbital planes. Note the top and bottom orientations that are perfect for eclipses (and the left and right that are not). Image taken from www2.astro.psu.edu (from Chaisson & McMillan Publishing). Click for a larger view.

Total solar and lunar eclipses, then, occur on special, but periodic and predictable, occasions when the Moon finds itself exactly in the Sun/Earth plane. When it’s just ever-so-slightly off this plane AND still between the Sun and Earth (or still falls into the Earth’s shadow in the Sun-Earth-Moon arrangement), we get partial eclipses. Just that simple.

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What to expect on April 15th (the government’s cashing in on its short wavelength tax!). Image from this article at io9.com.

Perhaps the most striking difference between a solar and lunar eclipse is that a solar eclipse obstructs the disc of the Sun, leaving only a view of its wispy exterior (corona), while a lunar eclipse alters the color of the Moon while still allowing us to see it in its entirety. Those watching the lunar eclipse will see the Moon go from its usual bright grey to orange, then a dark red before reversing the color order. The reason for this dark red coloring is the same reason why our sky is blue – the scattering of light in our atmosphere. Recalling our handy scattering relationship – that scattering (I) is proportional to 1 / wavelength4, we see that shorter wavelengths scatter more than longer wavelengths (because the wavelengths are in the bottom of the proportion, so larger numbers decrease the value of “I”). The image below was taken from one of the great non-wikipedia physics sites (well worth several afternoons to explore), hyperphysics.phy-astr.gsu.edu.

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The scattering relationship. See hyperphysics.phy-astr.gsu.edu/…/blusky.html for much, much more.

We see that shorter wavelength light gets “bounced around” more, while longer wavelength light passes for longer distances unimpeded by interactions with molecules and larger particles (like soot after big volcanic eruptions) in our atmosphere. Light going straight from the Sun hits our atmosphere and gets increasingly scattered as the wavelength gets shorter – blue scatters more than red, so we see the blue strongly when we look up during the day. With the blue light strongly scattered, those people on the edges of where the Sun’s light falls – those just starting or ending their days – see more red light because that wavelength wasn’t as strongly scattered – effectively those at sunrise and sunset get the filtered-out leftovers of the light that those at high noon see as blue. The “lit” side of the world experiences a range of different colors depending on where they are during the day, but all are being illuminated by waves of light from the Sun that left at the same exact time (plus or minus a nanosecond or two).

Because it’s a busy week and the author is feeling lazy, he refers you to the top image of the three-panel image below, showing how the scattering of sunlight in our atmosphere occurs sooner after entry (on average) for blue, a bit later (on average) for green, then a bit later (on average) for yellow, then out to red, some of which is and isn’t scattered (on average).

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The scattering of light by Earth’s atmosphere (shorter wavelengths scatter sooner). The other two images are placed into context by your reading about extrasolar planetary atmosphere studies. See www.universetoday.com/…-in-blue-light/ for that info.

And so, we know that blue is scattered strongly and red is not. This red light then races to the edges of our illuminated globe and the red light not scattered directly down to Earth or scattered in the opposite direction (out into space right above you) races past Earth at various altered (scattered) angles. During the most complete part of the lunar eclipse, the red color you see is, in fact, the red light that is passing through the edges of our atmosphere at those places experiencing sunrise and sunset (the sunlight performing a “grazing blow” of our atmosphere). As you might guess, if Earth were to lose its atmosphere (but don’t give any of your industrious friends any ideas), our lunar eclipses would appear quite different. Instead of a dark red Moon, we’d simply see a black disc where no stars shone (like placing a quarter at arms length and obscuring anything behind it).

Two (Maybe Three) Saturday Sessions Announced For The North Sportsman’s Club – Sept 12th, Oct 3rd, And (Maybe) Oct 10th

Greetings fellow astrophiles!

A red-lit view of the NSC building (and several tens of billions of stars towards the galactic center).

We are happy to announce a few new sessions at the North Sportsman’s Club to take us into the Fall and, for many, the near-end of their comfortable observing weather (although enough of us are crazy… about the Winter Constellations, so we’ll also brave any clear skies between December and March).

For those who didn’t make it to one of the sessions last year, the NSC is located in West Monroe, NY – take 81 to Exit 32, turn onto 49 East, then make a LEFT (at the next lights) onto Route 37 and go about a 1/2 mile North until you see the NSC sign on your RIGHT – maybe 15 minutes from downtown Syracuse. Map’ed out below.

The NSC in google maps. Click to generate directions.

The field provides an excellent Eastern horizon, complete with a distant radio tower red light for your Telrad aligning pleasure. For those who like to watch Earth’s rotation in real time – or see the very first arrivals of Messier Objects – tripod’ed binoculars pointed anywhere on the Eastern tree line and a comfortable seat will last you all evening. The East and North-East are wide open well to the North-West (so we’ll have many chances to view the Andromeda Galaxy at various point in the evening) and the tree line to the South and South-West block some of the distant light from Syracuse and related, making it a great spot for taking a lot of the sky in in very short order (weather-pending, of course).

The two (maybe three) sessions are as follows:

Saturday, September 12th – 8 p.m. to 11 p.m. – [meetup.com event & facebook event] coming up soon! The New Moon hits early in the morning on the 13th and the cold front arriving on Thursday should make the nighttime sky quite comfortable. Hopefully the clouds cooperate.

Saturday, October 3rd – 8 p.m. to 11 p.m. – [meetup.com event & facebook event] the 3rd Quarter Moon arrives close to 11:00 p.m. and our low, clear Eastern Horizon will make for some excellent final views for those with packed scopes but accessible binoculars.

* Saturday, October 10th – 8 p.m. to 11 p.m. – We’re currently holding the 10th as a weather-alternate for the 3rd. That said, if we get lots of interest, we’re going to run a session that evening as well.

We’ve added these events to our meetup.com and Facebook pages, and will make final announcements by 5:00 p.m. The evening of each session. Keep track of cnyo.org for any additional info (or drop us a line through our Contact Page). We hope to see your dark, featureless outlines at (at least) one of these sessions!

Free Astronomy Magazine – September-October 2015 Issue Available For Reading And Download

Greetings, fellow astrophiles!

2015sept6_freeastro_coverThe most recent issue of Free Astronomy Magazine (September-October, 2015) is available for your reading and downloading pleasure at www.astropublishing.com (click the link to go directly to the issue).

Free Astronomy Magazine was featured as the first of a series of articles on great free online content for amateur astronomers (see A Universe Of Free Resources Part 1) and we’ll be keeping track of future publications under the Online Resources category on the CNYO website.

You can find previous Free Astronomy Magazine issues by following this link: www.cnyo.org/tag/free-astronomy-magazine/

You can find previous Free Astronomy Magazine issues by checking out our Free Astronomy Magazine Category (or look under the Education link in our menu).

For those wanting a quick look at what the issue has to offer, the Table of Contents is reproduced below.

September-October, 2015

The web browser-readable version of the magazine can be found here:

www.astropublishing.com/FreeAstronomyMagazine_SepOct2015/index.html

For those who want to jump right to the PDF download (50 MB), Click HERE.

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