Eclipses, whether solar or lunar, occur because of the periodic alignments of the sun, Earth, and moon. These three bodies, orbit in space in very predictable paths (yes, the sun orbits too. It orbits the galaxy once every 200 million years!). Ever since the days of Kepler and Newton, we have been able to predict the motion of planetary bodies with great precision. So, why do eclipses happen?
The Moon moves right to left in its orbit around the Earth. The shadow it casts hits the Earth during the August 21, 2017 total solar eclipse.Solar Eclipses Happen when the moon moves between Earth and the sun. You might think that this should happen every month since the moon’s orbit, depending on how it is defined is between about 27 and 29 days long. But our moon’s orbit is tilted with respect to Earth’s orbit around the sun by about five degrees. Not much, you say? Yes, but the moon, itself, is only about ½ degree in width in the sky, about ½ the width of your pinky finger held at arm’s length. So, sometimes the moon misses too high and sometimes too low to cause a solar eclipse. Only when the sun, moon, and Earth line up close to the “line of nodes”, the imaginary line that represents the intersection of the orbital planes of the moon and Earth, can you have an eclipse.
The Moon orbits the Earth in the months prior to the August 21, 2017 total solar eclipse. Viewed from above, the Moon’s shadow appears to cross the Earth every month, but a side view reveals the five-degree tilt of the Moon’s orbit. Its shadow only hits the Earth when the line of nodes, the fulcrum of its orbital tilt, is pointed toward the Sun.
This is true for both solar and lunar eclipses. This situation is somewhat unique as no other moon in the solar system orbits roughly in the plane of the “ecliptic”, Earth’s orbital plane, that the planets more or less follow.
When the moon does eclipse the sun, it produces two types of shadows on Earth. The umbral shadow is the relatively small in diameter point on Earth where an observer would see a total eclipse. The penumbral shadow is the much larger area on Earth where an observer will see a partial eclipse. Here, the sun is not completely covered by the moon.
PORTLAND, Ore. (KOIN) — It’s true Portland metro is not in the path of totality for the August 21 solar eclipse. But it’s pretty close.
Portland will experience 99.4% of totality at 10:19:07 that Monday morning.
So where is the best place in this part of the region to see the eclipse? Jim Todd from OMSI suggested looking to the southeast and be in an open area to see the moon’s shadow come and go
Todd said you’ll be able to see Venus to the right of the sun
It may be a good idea to stick close to home: ODOT officials said the eclipse may cause the greatest traffic jam in Oregon history.
Don Hamilton with ODOT said there may be a million people who descend on the state for the eclipse, especially in the 60-mile path of totality that spans the state from west to east.
The risk of wildfires is increased during the eclipse as well — not from the eclipse, but from the thousands of campers and out-of-staters unfamiliar with the terrain and dryness.
And don’t forget to get the right kind of eyewear. Without certified glasses, the eclipse could fry your eyes
Eclipse concert crowds jam Prineville-area roadways
PRINEVILLE, Ore. – Thousands of festival-goers heading to Big Summit Prairie have been traveling through Prineville since Wednesday, causing traffic backups of 15 to 30 miles east of town, according to authorities.
Oregon State Police reported late Wednesday a 30-mile backup from the concert site, where 30,000 or more people are expected to attend the weekend event that begins Thursday.
Here’s a news release issued Thursday morning by Crook County:
Traffic has been extremely heavy traveling East through Prineville since Wednesday, August 16th. We saw an increase in congestion later in the day yesterday with traffic traveling East toward Big Summit Prairie. Already today traffic is heavy from just west of Prineville headed east through town.
County operations and Law Enforcement is working with County Emergency Management, Fire and EMS as well as the Road Department and ODOT to mitigate the impact to our community.
Crook County Sheriff, City of Prineville and Crook County Court strongly urge travelers who do not need to travel today or early on Friday please consider delaying your journey. Traffic later on Friday the 18th and over the weekend is expected to still be heavy but moving better as most of the attendees of the event at Big Summit Prairie will have already arrived at their destination.
If you do need to travel today or Friday please be aware of the higher than normal traffic and congestion through Crook County and plan accordingly for your trip with extra water and snacks. With the high temperatures our region is expecting plan to stay hydrated. Practicing patience will help make your journey more enjoyable.
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