It's one of the most spectacular astronomical events in the U.S. and will be watched by millions and millions.

MIAMI – Sudden darkness, a hush, and stillness, is expected when America experiences a total solar eclipse on August 21 casting the nation into temporary darkness as the moon passes between the Earth and the sun. For many, this will be a once in a lifetime opportunity.

It's one of the most spectacular astronomical events in the U.S. and will be watched by millions and millions. In Oklahoma, astronomers predict Miami will be the best spot in the state to view the eclipse.

Dr. Fred Espenak, a retired astrophysicist of NASA’s Goddard Space Flight Center, agency expert on eclipses, author of numerous books on eclipses and known as “Mr. Eclipse,” has traveled the world to witness and study solar eclipses.

“A total eclipse is the most spectacular natural phenomena you can possibly see with the naked eye,” Espenak said. “People who haven’t seen one just can’t understand how dramatic and spectacular it is. There are no words I can tell you. There are no videos or photographs I can show you – it’s one of those things you just have to experience yourself.”

The excitement is growing as the greatest free spectacle draws nearer. This is the first eclipse to cross the entire continental United States in almost a century, and the excitement and interest is building to a frenzy across the country. The next total eclipse in the U.S. will not happen until April 8, 2024.

Monday, August 21, will mark the first total eclipse in the United States since 1979. And it’s been even longer since the last total solar eclipse crossed from the Pacific to the Atlantic - that occurred June 8, 1918, when an eclipse crossed from Washington to Florida.

Local Miami residents are joining the masses in planning for viewing the magnificent event.

“My husband and I are going to Kansas City,” Whitney Cantwell said.

Kansas City is in the eclipse’s path of totality as well as nearby Missouri cities such as St. Joseph, Jefferson City, Columbia, and others.

“We are going camping near Meramec State Park in Missouri. It is supposed to be totally dark for two and a half minutes there. Dark enough for the streetlights to come on," Terri Shehan said.

“I have my glasses and driving to Columbia, Mo. and will probably sit in a Walmart parking lot!” Jan Underwood said.

Some area science teachers are purchasing solar glasses to allow students to watch the eclipse since school will be in session.

Miami photographer Gary Crow is traveling to Hopkinsville, Kentucky to attempt to capture images of the solar eclipse. Hopkinsville has been named the best place in the U.S. to view the eclipse and has even temporarily changed the name of the town to Eclipseville. The small town of 32,000 is expecting a huge surge of over 100,000 people coming from all over the world to witness the solar phenomena.

Solar Eclipse

As the moon passes between the Earth and the sun, the moon will block the view of the sun and cast a shadow. Total solar eclipses transpire when the cosmic coincidence of the moon, which is 400 times closer to earth and 1/400th of the sun’s size line up perfectly.

This extraordinary coincidence is why a total solar eclipse occurs when the Earth, sun, and moon align.

Those standing in the shadow will see the sky darken and feel the temperature drop. The sun will look like a dark, black circle in the sky and only the sun's corona or halo of extremely hot gas will be visible.

It’s purported that animals, insects, and birds will grow silent as the moon passes over before the sun casting a shadow.

In the U.S. the eclipse shadow first hits land north of Newport, Oregon at 10:15 a.m. Pacific time and will make its way across the southeast, across the nation in a diagonal path of totality, and leave the continental U.S. close to Charleston, South Carolina around 2:29 p.m. Eastern time.

Path of Totality

According to experts the “path of totality” is a 70- mile wide, 3,000-mile long swath in the direct shadow of the moon, known as the “umbra.” The path of totality will move across 14 U.S. states. Because of the moon orbits Earth quickly, 2,100 miles-per-hour, each spot in the path will experience approximately two minutes or slightly more of total darkness.

The path of totality shadow will cross the entire U. S. in about 90 minutes, faster than the speediest jet.

“About 10 or 15 minutes before the temperature starts to drop, animals start to react to it, cows will head back to the barn, flowers will start to close up, maybe crickets will start chirping, and in those last 10 minutes the light starts to look very strange,” Espenak said.

In the last two minutes, the physicist says you might see rippling bands of light and shadow racing across the landscape, called shadow bands caused by the crescent sun shining through the upper atmosphere of the earth. It’s related to the same physics that cause the stars to twinkle, according to Espenak.

The total solar eclipse continues to awe even a seasoned NASA astrophysicist who paints an ethereal picture of the eclipse.

“Then in the last 30 seconds the daylight just visibly fades, and suddenly you’re in twilight. You go from daylight to twilight in about 30 seconds, and it’s about as dark as the sky gets maybe a half hour after sunset, it’s not as dark as night. So you can see maybe a few bright stars and some planets in the sky. It’s very startling. The hair on the back of your neck stands up, you get goosebumps, you feel an odd feeling in the pit of your stomach,” Espenak said. “What you couldn’t look at moments before, you can look at because that brightness is gone. You look up in the sky, and it’s replaced by this eerie black disc of the moon seen in silhouette against the Sun’s solar corona.”

At that point, the eclipse is completely safe to look at without protective eyewear, according to Espenak.

“You look around the horizon, and you’ve got the colors of a sunset 360 degrees around the horizon as you’re looking out around the moon’s shadow,” Espenak said. “All of this happens in such a short amount of time. And then within two and a half minutes or two minutes and 40 seconds at the maximum, the sun appears as a bright bead at the edge of the moon and you see something called the diamond ring effect where the corona forms a ring, and the bead of sunlight is the diamond. It quickly grows too bright to look at and then you see the shadow rushing off to the east.”

It is estimated 12 million people will experience the eclipse in the path of totality, and as many as 7 million others will migrate to the path.

“At the end of totality you see people with tears running down their cheeks,” Espenak said.

Those outside the path of totality will experience a lighter cast shadow from the moon, known as the “penumbra.” All of North America will experience a partial eclipse and see the sun partly covered by the moon.

“During a partial phase, unless you’ve got on eclipse glasses you would never know an eclipse was taking place,” Espenak said. “But really it’s in the last 10 to 15 minutes that the lighting in the landscape starts to drop.”

Espenak said if you are standing under a shade tree the eclipse can be seen in the patches of sunlight passing through the leaves.

“The leaves will act as a pinhole camera and project images of the crescent sun all over the ground,” he said. “In fact, if you take a straw hat, if you take a kitchen colander, anything with a bunch of holes and it and hold it up three or four feet above the ground it will project images through all of the holes of the eclipsed sun.

Here in Miami, 93 percent of the sun will be covered at the peak of the eclipse, which is expected to occur just after 1 p.m.

Cloud cover could affect eclipse viewing, so observers are keeping a watch on the weather forecast.

Eye Protection

Experts warn those watching the eclipse to wear protective glasses for the event or risk severe eye damage. The ultraviolet rays from the sun can literally burn eyes, and regular sunglasses do not filter well enough. Only glasses with specially designed solar filters are adequate and can be bought at many retailers for under a dollar.

“The sun is dangerous to look at any day because it’s so exceedingly bright. As kids remember taking a magnifying glass and holding it over a newspaper and lighting it on fire. Well, that’s what happens if you’re staring at the sun- you’re shining that kind of concentrated light into your eye. So, if you look at it long enough it’s going to burn the retinas,” Espenak said. “Well, there’s nothing different going on, and that’s a danger during an eclipse. Human nature and curiosity get the better of us, and we stare at it when we know we shouldn’t.”

Mr. Eclipse

Espenak says his love and passion for astronomy started early.

“I was an amateur astronomer as a kid, and I saw a partial eclipse, and that got me interested in reading up about them. I said ‘Well, I really want to see a total one.’ I just got my driver’s license and drove 600 miles to get in the path, and after it was over, I was just literally blown away. I said, ‘This can’t be a once in a lifetime experience. I’ve got to see another one.’”

Two years later Espenak drove to Canada, but the view there was clouded out, he then traveled to the Sahara Desert in Africa, and began traveling the world chasing eclipses.

“I’m going to try to see as many of them as I can,” Espenak said. “Now I’ve seen them from every continent including Antarctica. I’ve been to 27 total, and I’ve seen about 20 of them. It’s surrealistic.”

Science

This solar eclipse allows an important opportunity for scientists to study the sun’s corona, which is normally not visible because the eclipse’s umbra and penumbra path across land will remain within sight for the duration. Researchers positioned at various locations along the path of totality can film the event and piece their clips together to create an unprecedented 90-minute video of the corona in action.

“It’s the best time to see the corona,” Espenak said. “This is a great opportunity to make detailed measurements of the inner parts of the sun’s corona. One of the big mysteries about the corona still to this day is that the surface of the sun is about 10,000 degrees Fahrenheit, but the corona is one to two million degrees, so the real question is why? Normally, let me give you an analogy, if you have a campfire that represents the surface of the sun if you move away from the campfire it gets cooler, but with the sun when you move up to the corona it gets hotter.”

There have been 10 eclipses visible in the U.S. in the past 100 years, in 1918, 1923, 1925, 1932, 1945, 1954, 1959, 1963, 1970, and the last in 1979.

Eight eclipses will occur in the next 100 years visible in the U.S. in 2024, 2044, 2045, 2052, 2078, 2079, 2099, and 2106.

"It’s been 38 years since the lower 48 states has had a total eclipse, so we’ve had a long time to wait for it,” Espenak said.

Espenak said he will be watching this eclipse from Caspar, Wyoming with 15 cameras in operation.

“A number of TV stations have asked me to do interviews on eclipse day, and I told them, ‘Are you out of your mind,’” Espenak said laughing.

Once in a lifetime

“It’s breathtaking,” Espenak said. “The word awesome is overused in this day and age, such as ‘Oh man I had an awesome pizza for dinner last night,’ No, no, when you see a total eclipse that inspires awe to you! That is the definition of the word awesome. Once you see a total eclipse you will understand what the word awesome really means.”

The physicist gives one piece of advice to eclipse viewers.

“A lot of people would say well it’s going to be 90 or 95 percent from where I live, and that kind of argument is like saying I almost won a jackpot. The difference between seeing a 100 percent total eclipse and an 80 to 95 percent is the difference between winning the lottery and being one number off. There’s absolutely no comparison,” Espenak said. “It’s the difference between day and night. It’s like the difference between going to the Super Bowl and sitting out in the parking lot versus having a box seat. With total eclipses, it’s either 100 percent or nothing.”

NASA offers an interactive eclipse map to help determine time, and duration of cities in the U.S. at https://eclipse2017.nasa.gov/sites/default/files/interactive_map/index.html.

Melinda Stotts is the associate editor of the Miami News-Record. She can be emailed at mstotts@miaminewsrecord.com or followed on Twitter @MelindaStotts1.