The moon slowly drifted across the sun before blocking out its rays in a total eclipse starting on the US west coast on Monday, as a rare cosmic event moved across continental the United States.
The first visible sign of the total eclipse was observed in Oregon at around 10:15 am (17:19 GMT).
The total eclipse zone then moved across 14 states ending in South Carolina Monday afternoon, taking in all about two hours.
Some 12 million people live within the 113-kilometer-wide (70-mile-wide), 4,000-kilometer-long (2,500-mile-long) total eclipse line, while several million people also traveled into the total eclipse's path.
Totality, when the moon moves in front of the sun until it blocks all light except its outer atmosphere, or corona, lasted two minutes at each point along the eclipse route. It began over Lincoln Beach, Oregon at around 17:16 GMT.
A partial solar eclipse was also visible across the US and large parts of Canada and Mexico.
President Donald Trump watched a partial solar eclipse blocking 81 percent of the sun from the White House, the administration said.
Despite the known risks of looking straight into the sun, not everyone could resist
NASA also covered the event for those unable to see it first hand. The space agency reported that some 4.4 million tuned in to watch its livestream event.
Read: A very bried history of total solar eclipses
Read: Animals turn a blind eye to solar eclipse
It is the first coast-to-coast total solar eclipse in the United States in nearly a century. It is also the first total eclipse visible from the contiguous United States since 1979. The next solar eclipse in the US will be in 2024, although the next coast-to-coast eclipse won't be until 2045.
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Our sun: a ball of superhot gas
Ancient fireball
Our sun had already been shining for billions of years before mankind even existed. Together with the planets of our solar system, the sun developed from a gas cloud 4.6 billion years ago. And it will probably continue shining for another five billion years, until its energy reserves run out.
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Our sun: a ball of superhot gas
A big idol for energy researchers
The sun is basically a huge nuclear fusion reactor. At its core, pressure and temperature are so high that hydrogen atoms merge together to form helium atoms. This process releases huge amounts of energy. One thimble of sun material generates as much energy as burning thousand metric tons of coal does.
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Our sun: a ball of superhot gas
100 times bigger than Earth
Seen from Earth, the sun doesn't seem big - it is just a bright spot in the sky. But it does have a radius of about 700,000 kilometres (435,000 miles). Its core is 15 million degree Celsius (27 million degree Fahrenheit). Temperatures on the sun's surface still reach 5500 degree Celsius (10,000 degree Fahrenheit).
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Our sun: a ball of superhot gas
One in a billion
All stars in our universe glow because they generate energy deep down inside. Our sun is just like other billlions of stars scattered across the universe. In comparison with other stars, our sun is of medium size. Some stars are a hundred times bigger, others are just a tenth of the sun's size.
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Our sun: a ball of superhot gas
Restless on the outside
The sun's surface is seething away. Hot and brightly glowing material ascends from the sun's inside, cools and sinks down again, appearing much darker. Our sun is the only star in the universe so close to Earth that astronomers can observe in such detail.
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Our sun: a ball of superhot gas
Amazing sunspots
Sometimes big dark spots appear on the sun's surface staying for about a month. Even before the birth of Christ, humans already knew of those spots, and Galileo Galilei later recorded their appearance in writing. But for a long time people were mystified where those spots came from. Now we know the answer: they're areas with a particularly strong magnetic field.
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Our sun: a ball of superhot gas
Dangerous storms
When the sun is very active, geomagnetic storms develop. It's when the sun catapults a particularly high number of charged particles into space. Those particles can hit and destroy satellites. They might also disturb electric power substations on Earth and even lead to power breakdowns.
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Our sun: a ball of superhot gas
When the sky glows
This is another, much more beautiful effect of geomagnetic storms: an aurora, also called polar light. It occurs when charged particles of the sun hit the Earth's atmosphere. The frequency of how often we may enjoy this spectacle depends on the solar cycle. Every eleven years the sun is particularly active - that's when many geomagnetic storms and auroras can be observed.
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Our sun: a ball of superhot gas
Please remember!
Never watch a solar eclipse without protecting your eyes. Even when the moon partly covers the sun, it is still extremely bright. Without sun protection you risk damaging your eyes - the retina can completely burn up. Fortunately, there are special eclipse glasses for such an event. They even look stylish, don't they?
Author: Alexandra Hostert
cw/bk (AFP, AP, dpa, Reuters)
