Faculty voice:

Shannon Schmoll: The Great American Eclipse

Aug. 16, 2017

Shannon Schmoll is the director of the Abrams Planetarium through the Department of Physics and Astronomy. Next week, most of North America will have the opportunity to see an incredible solar eclipse that will perfectly align the Earth, moon, and sun.

Astronomy is remarkable because it has the potential to connect everyone, both around the world and through time. The stars, moon, sun, planets and the patterns of motion we see are the same for everyone today and throughout history.

Interpretations are different across cultures and time, but not what we physically see. We can use those common observables to help us connect and maybe understand each other a little better. Some astronomical events, though, cannot be seen or experienced by everyone, but they can still bring people together. One such event is the total solar eclipse that will be visible from the continental United States on Aug. 21.

Not everyone will be able to see the eclipse because you need to be in the exact right spot. Solar eclipses happen when the moon perfectly lines up between the sun and Earth. The moon passes between the Earth and sun every 28 days, but its orbit is tilted causing it to appear just above or below the sun most times. Though when it does line up perfectly, the moon will cast a shadow. If you are under the darkest part of that shadow you will see a total solar eclipse. This shadow moves across the Earth in a line called the path of totality.

The Aug. 21 eclipse is being touted as the Great American Eclipse, which is apt as the path of totality will pass from coast to coast. It will first be seen in the United States in Oregon and follow a nearly straight path through the middle of the U.S., ending in South Carolina. This path is making the eclipse accessible to many people in our vast country, creating a national collective experience that future generations may get tired of hearing. Many people have made travel plans to the best spots to experience the eclipse with total strangers. Others are instead using this as a reason to see friends or family in or near the path of totality.

If you are planning to see the eclipse there are a few things you need to know. The entire moon moving across the face of the sun will last about two hours. Totality, when the moon completely obscures the sun, will last about two minutes and totality will begin anywhere between 10 a.m. to 2:45 p.m. local time. Check exact times and totality durations for your location beforehand so you do not miss it. Watch out for weather and traffic is expected to be particularly bad, so have back up plans ready.

During totality, the sky will go dark and temperatures will drop noticeably. You will see the main disk of the sun blocked by the moon and a halo of white light from the sun’s outermost atmosphere. You will be also able to see stars and planets during the day. Look for winter constellations such as Orion or Gemini near the western horizon. Mars will be just west of the sun and Venus should appear very bright farther west.

Even if you cannot make it to the path of totality, there will still be something to see. All of North America will see at least a partial solar eclipse. The sky will not go dark, but it will still be an amazing sight and worth dragging those around you outside to check it out. If you still want to see a total solar eclipse and miss this year’s, there will also be another total solar eclipse coming our way on April 8, 2024 in a path from Texas to Maine.

No matter if you see the total or partial eclipse, YOU NEED TO PROTECT YOUR EYES! You can purchase eclipse glasses from reputable sources that will block sufficient light. Other options include using welder’s glass number 14 or higher or building a device that will show you a projection of the sun’s image.

The only time you can take off your eye protection to look at the sun is during totality itself, when the moon completely obscures the sun. You will need to take off your glasses to see the sun during this time. Never take off your eye protection when viewing a partial solar eclipse. As soon as a glimmer of sunlight appears put your eye protection back on. If not, you might end making new friends in the emergency room instead.

RESOURCES:

More information on future eclipses and where to see them

Learn more about what to expect and check times for your location

Where to buy eclipse glasses

More Information on where to view and events near you and additional resources

 

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