Thursday, October 16, 2014
Partial solar eclipse visible this upcoming Thursday
This upcoming Thursday, students here at BYU will get the unique opportunity of viewing something that only happens once every few years: a solar eclipse.
An eclipse occurs when the sun, the Earth and the moon are all lined up together. In the case of a lunar eclipse, the Earth is between the sun and the moon. This causes the Earth to cast a shadow on the moon during its full moon phase. A solar eclipse, on the other hand, is the exact opposite. During the new moon phase, when the moon is between the sun and the Earth, the moon blocks the light of the sun and casts a shadow on the Earth.
Dr. Jeannette Lawler, the planetarium director at Brigham Young University, said, “If everything was actually exactly lined up, then every single month as the moon orbits around the earth, it would come in between the earth and the sun and it would block out the sun and we’d have a solar eclipse.”
Lawler further explained that the reason this doesn’t happen every month is because the sun, the Earth and the moon aren’t always perfectly lined up. First off, the moon’s orbit is a bit tilted, so it’s not always on this perfect plane with the sun and the Earth. Second, the Earth itself also rotates on a titled axis. These factors make eclipses a lot more uncommon and thus exciting for people to seek out and view. A solar eclipse is even more exciting because the shadow that the moon casts on the Earth is a lot smaller than the one the Earth casts on the sun, thus making solar eclipses a lot less common than lunar eclipses.
A lunar eclipse has already happened a couple times this year, the most recent occurrence being just over a week ago very early in the morning on Wednesday October 8. Being that it takes the moon roughly four weeks to orbit around the Earth, two weeks following the lunar eclipse is when the solar eclipse will take place. Specifically, that date is Thursday October 23. In the Salt Lake area, it will start at about 3 p.m. and finish around 5 p.m. The height of the eclipse will be between 4 p.m. and 4:30 p.m.
This solar eclipse is not, however, a total solar eclipse. It’s a partial solar eclipse. A total solar eclipse occurs when the sun, the moon and the earth are perfectly lined up, which is not the case in this instance. In addition to needing everything perfectly lined up, one would need to travel to the right place to see a total solar eclipse since the shadow of the moon is only present in certain places.
This makes a total solar eclipse even rarer than any other eclipse. In fact, Lawler mentioned that while a partial solar eclipse occurs every few years, a total solar eclipse that is in driving range only happens once every decade or two. A few years back, a total solar eclipse was visible in the St. George. And for future astronomical adventures, there will be a total solar eclipse in 2017 that will be visible in Southern Idaho. In fact, it will pass right over fellow BYU school, BYU-Idaho.
So how can one view the partial solar eclipse that will be visible in the Western United States and Western Canada this upcoming Thursday? First off, walking outside and looking at the sun with no protection is the way not to go.
“You cannot go out and stare at the sun if you want to actually be able to see afterwards. Just like a magnifying glass—you can use it to fry ants– the lens in your eye will focus the rays on the back of your retina and burn little crispy spots in the back of your retina,” said Lawler.
Lawler also said to avoid jury-rigged methods that you can find on the internet such as putting three lenses together. The best way, she said, was to actually purchase a pair of solar glasses that can be found at various places around town or can be purchased on the internet for only a couple of dollars. In preparation for the eclipse, the BYU Bookstore ordered some of these glasses. They can be found in the Twilight Zone of the bookstore for only $0.99. Lawler also suggested sharing the glasses with friends or roommates instead of every individual purchasing their own, since not many people will probably watching the eclipse for the full two hours.
The other way that Lawler suggested to view the eclipse is through BYU’s astronomy club. They will be setting up solar telescopes on campus that are equipped with special solar filters that will make viewing the eclipse possible without ruining one’s vision.
“It’s one of those things that I think everybody should take a look. It’s certainly worth spending your time to go ‘Yeah I saw that and it’s kinda cool and now I’ve done it.’ Because they don’t happen all that often,” said Lawler.