North America is preparing for a once-in-a-century total solar eclipse which will plunge large parts of the United States into darkness.
Parts of 14 states will witness the solar spectacle, which is being described as the Great American eclipse
Read on for more details and have a go at our eclipse quiz at the bottom of this page.
Where is it and when?
Monday 21 August 2017. It starts at 9.05am local time on the Pacific coast (5.05pm UK) and finishes at 4.09pm local time on the east coast (9.09pm UK).
:: Great American Eclipse: Where and when to watch
Its path completely crosses the continental United States - from Oregon in the west to South Carolina in the east.
A 70-mile-wide strip will experience total darkness in the middle of the day, while a partial eclipse will be visible from much of North America and from parts of Europe - including, briefly, the UK.
The area around Carbondale, Illinois, will experience the longest period of darkness - 2 minutes 41.6 seconds. But the most perfect eclipse will be visible in Hopkinsville, Kentucky, where the Sun, Moon and Earth will be in greatest alignment.
States including Idaho, Wyoming, Nebraska and Tennessee will all experience 'totality' - where the moon fully covers the Sun.
What causes an eclipse?
A solar eclipse is caused when the Moon passes in front of the Sun. Partial eclipses happen all the time but a total solar eclipse - where the Moon completely covers the Sun - is much rarer.
Although the Sun is much bigger than the Moon, it is also much further away. An accident of nature makes them appear the same size from Earth, so when the Moon and Sun align it gives the impression that the Sun has been completely blocked out.
NASA scientist Dr C Alex Young said: "What's really cool is that this is moving across the continental United States. We have eclipses fairly often but the world is a big place and so they are not always happening in places first of all on land and they are especially not happening with such a huge population. That is why this an amazing event."
How common is a solar eclipse?
The US mainland has not seen any sort of total solar eclipse since 1979, but you have to go back to 1918 for one that has crossed the country in the way this one will.
Although this one has taken almost 100 years to come about America won't have to wait so long for the next one, as large parts of the US will experience another total solar eclipse in April 2024.
But that will just whet appetites for the 'Big Daddy' total eclipse on 12 August 2045 which, weather permitting, will be the most impressive of the 21st century.
Britons have to wait much longer as the UK's next total solar eclipse is not until 2090, though there will be a significant eclipse in August 2026 when 90% of the Sun will be covered.
How is the US preparing?
Americans aren't known for missing a trick when it comes to commercial opportunities and the Great American Eclipse is no exception.
An estimated two-thirds of the US population lives within one day's drive of the path of the eclipse and the event is being widely used to try to attract tourists.
:: Eclipse will cause 'greatest ever' influx of tourists
In Illinois - which should get a good view - Ozzy Osbourne will headline an eclipse musical festival called 'Moonstock'. Madras, Oregon, hosts a three-day 'Solarfest' and Caspar, Wyoming, is holding not just a festival but an astronomy convention, too.
:: Bonnie Tyler
For some, though, it is not just about fun. Emergency plans are in place in many states, with authorities fearful about the sheer numbers of people who may turn up.
Hospitals have brought in extra supplies, portable toilets have been booked, plans have been made for gridlock and arrangements have been made in case there are excessive demands on power supplies.
Huge numbers of eclipse glasses are being sold amid warnings not to look directly at the Sun, because it can cause severe damage to your eyes.
What will we learn?
Scientists will use the eclipse as a research opportunity. NASA is sending up 50 high-altitude balloons to simulate how life may be able to survive beyond Earth.
:: NAS
The space agency will also live-stream aerial footage of the event.
Another team will 'chase' the eclipse using an aircraft. Project co-investigator Dan Seaton, from the University of Colorado in Boulder, said: "Going to very high altitude might allow us to see a few events or track waves that would be essentially invisible in just two minutes of observations from the ground."
No comments:
Post a Comment