An astronomer from the University of Warwick explains the science behind and what to expect from the upcoming Total Solar Eclipse (TSE).
Professor Don Pollacco, Department of Physics, shares his expertise to mark Global Astronomy Month, which runs throughout April.
This month hosts one of the most eagerly anticipated events of the astronomical calendar – a TSE, visible across America and Mexico, on 8th April. In the UK, viewers will be treated to a partial eclipse of the Sun.
Professor Pollacco explains: "TSEs occur on average about every 18 months but the visibility path of seeing the full total eclipse is extremely narrow, around just 80 miles. If you are not located within that track, you will not see a total eclipse."
"The path of totality starts in the South Pacific and moves through Mexico and up through the USA, before finishing in the Atlantic, west of Ireland.
"From the UK and Ireland, you will see a partial eclipse of the Sun close to sunset, with about 20-30% of the Sun obscured by the Moon. The next total eclipse of the Sun visible from the UK is in 2090. There is another in 2026 that is visible in northern Spain, tracking up to Iceland.
"The best views of the total eclipse will be in Mexico and Texas (west of Austin) and this eclipse could potentially be seen by many millions of people, even though eclipses usually occur in remote areas. In these places the Sun will be close to overhead at totality."
What is it like to experience a TSE?
The TSE will offer an incredible and unusual experience, in which, at totality, flares of the Sun's corona will appear like a diamond ring in the sky. As the Earth is plunged into darkness, planets and comets may even be visible to the naked eye. The event may even disrupt communications back on Earth.
Professor Pollacco, who is travelling to the USA to view the TSE, said: "Total eclipses of the Sun are amazing and feel quite magical. From the right vantage point, you can see the Moon shadow rushing towards you at 1,000 miles an hour as totality approaches.
"When almost obscured as the Sun's light shines through valleys on the Moon's limb, you see the famous Baily's Beads (beads of sunlight emerging from the eclipse shadow) and, when the final valley is lit up, the Diamond Ring (which appears as a faint corona around the Sun, as a glittering ring).
"At this time, turning off the sunlight has effects high up in the Earth's atmosphere, which may impact communications, and produce the strange shadow bands on the ground – making the ground swirl around as you look at it.
"During totality we can see the Sun's atmosphere. The Sun has an 11-year activity cycle and the shape of its atmosphere changes during the cycle. At this eclipse the Sun is close to the peak of activity, so the atmosphere is expected to have long streamers heading away from the Sun. It's also likely that 'pink blobs' called prominences will be visible on the Sun's limb.
"As the sky gets darker, planets and bright stars will be visible. It's also possible that an unknown comet may be seen for the first time near the Sun. At the end of totality, you see the Diamond Ring and Baily's Beads again, as the Moon shadow leaves and the sky gets bright."
From Mexico the total eclipse will last 4.5 minutes. While this does not seem long, the maximum eclipse length possible is about 7-8 minutes.
"It's quite a thought that if you chase all the eclipses during your lifetime you will stand in the shadow of the Moon for about an hour", said Professor Pollacco.
How can TSEs be viewed safely?
Remember looking directly at the Sun, even during the eclipse, can be dangerous; you need to take the appropriate equipment and eclipse glasses are generally readily available. You can also project an image of the Sun through a pin hole onto a screen.
Professor Pollacco added: "With no protection you will at best damage your eyes, or you could blind yourself."
