February 17 2018
Total Solar Eclipse. On Monday, August 21, 2017, all of North America will be treated to a total eclipse of the sun. Anyone within the path of totality can see one of nature's most awe-inspiring sights - a total solar eclipse.
A million people may flock to Oregon over the coming week to view perhaps to some, a once in a lifetime event.
Oregon officials said Tuesday that they're as prepared for the eclipse. Govenor Kate Brown declared a state of emergency, but it's mostly to clear red tape so state and local agencies can work together to respond to any problems that arise.
BACKGROUNDWhen seen from Earth, a solar eclipse happens when the Moon passes between the Earth and the Sun. This makes the Moon fully or partially (partly) cover the sun. Solar eclipses can only happen during a new moon. Every year about two solar eclipses occur. Sometimes there are even five solar eclipses in a year. However, only two of these can be total solar eclipses, and they are quite uncommon.
The area of a total eclipse is only a narrow track along the Earth. The total shadow of the moon in front of the sun lasts only a few minutes. Outside this path, all eclipses are partial, and places far from the track get no eclipse at all. The path of the eclipse is predicted many years before it occurs. Eclipse chasers or "umbraphiles" (the moon's shadow is called an umbra) travel from distant places places to see solar eclipses. After the solar eclipse on August 11, 1999, in Europe, people began to show more interest in solar eclipses.
Long ago, solar eclipses were considered supernatural or even a sign that something bad was about plunge all of humanity into the dark ages once again. Strangely, many people still hold on to this believe in some cultures today, frightening some people who don't understand the science.
Solar eclipses happen somewhere on Earth almost every year, and very similar solar eclipses happen every 18 years, 11.3 days. This period is called the Saros cycle.
There are four different types of solar eclipses:
A total eclipse is when the Sun is completely hidden behind the Moon. The dark shadow of the Moon covers the very bright surface of the Sun. This makes the corona easier to see. An annular eclipse is when the Sun is directly behind the moon, but it looks like the Moon is smaller. This makes the Sun appear as a very bright ring or annulus around the shape of the Moon.
A hybrid eclipse (also called annular/total eclipse) is when it appears like a total eclipse in some parts of the Earth, and an annular eclipse in other areas. Hybrid eclipses do not occur as often as other eclipses.
A partial eclipse is when the moon is not precisely between the Sun and Earth, so it doesn't totally shadow the sun.
The Sun's distance from the Earth is 93 million miles or about 400 times the Moon's distance, and the Sun's diameter is about 400 times as big as the Moon's. This is why the Sun and Moon seem to be about the same size from Earth.
Looking directly at the bright surface of the Sun itself can hurt the retina of the eye because of the radiation from the Sun, blind careless people. The retina does not feel pain, so damage may not be felt for hours.
The Sun is usually so bright that it is hard to look at it directly. However, when the Sun is covered in an eclipse, it's easier to witness the event. Looking at the Sun during an eclipse is equally dangerous, except in the very short time when the Sun's surface is completely covered. Looking at the Sun's surface through binoculars, a telescope, or even a camera is extremely dangerous and can damage the eye in less than a second.
Looking at the Sun without an eclipse may permanently injure your eyes, even though the pupil of the eye closes down. Be extremely careful with your child, even a short glimpse could result in seeing saturated white spots days later. If the sun is almost completely covered, the pupil opens because there isn't as much light. However, the parts of the sun that can be seen are still equally bright, and can damage your eyes. So be extremely careful.
Now everyone needs to wait for the weather. The enemy of an eclipse is cloud formation. Cloudy skys can ruin a once in a lifetime celebration.
Tyree Wilde of the National Weather Service in Portland says no major weather systems are predicted to move into the state before Monday, but some areas could have patchy clouds.
"Right now it looks like central and eastern Oregon has the best chances of viewing the eclipse," he said.
"West of the Cascades, we have kind of a greater likelihood of some clouds moving through from time to time."
The possibility of lingering morning clouds along the coast has officials with the Oregon Department of Transportation concerned. Spokesman Tom Fuller has a warning for people who might try to hurry to a different viewing location based on cloud cover the day of the eclipse.
"The bottom line is, don't do it," said Fuller. "There's just no way, if there's cloud cover on the coast, you're going to make it back to the valley in time to see the eclipse."
Fuller says that even if people don't attempt a last-minute switch in viewing locations, heavy traffic will still clog roads.
"Getting around on the state highway system with a million extra visitors to the state is going to be problematic, at best," he said.