BRIGHT IDEAS AND GAZING TO THE FUTURE
▶ With American eyes turned skyward this week to view the solar eclipse, Jonathan Gornall reflects on our relationship with the Sun
Where does the Sun go each night when it sinks below the horizon? Why is it occasionally seen during daylight hours in the company of its generally nocturnal sidekick, the Moon? And what on earth is going on when the former is briefly blotted out by the latter?
In the centuries before we finally figured out that it was the Sun, and not the Earth, around which our universe revolved, these were not unreasonable questions. Given the extent to which life was utterly dependent upon the daily appearance of the Sun and the seasons that trailed its progress through the sky, the answer that many cultures came up with was equally reasonable.
To early African cultures, the ancient Egyptians, Greeks, pre-Islamic Arabs, Vikings, ancient Britons, Romans, Incas and assorted others, the Sun was obviously a god. Capable of gazing down upon our mortal dreams and endeavours with benign warmth or cold indifference, it was to be kept on side at all costs with regular worship and, whenever necessary, appeased with sacrifices.
Things have changed, of course. Thanks to the ingenuity of human beings such as Nicolaus Copernicus, who developed the first heliocentric model of the universe in the 16th century, and the scientists who since 1960 have flung 19 different probes in the general direction of our local ball of fire, there is very little we now don’t know about the Sun.
It isn’t, it turns out, a deity. Instead, it’s an extremely hot ball of fiery gases, chiefly hydrogen and helium, burning at a temperature of 10,000°F at the surface and an extremely toasty 27 million degrees at its core. Thankfully, the star at the centre of our solar system is 150 million kilometres from us – which is just far enough. Scientists believe if we were a mere 1.5 million kilometres closer, it would be game over for life on Earth.
We also know that the Sun is very large – it has a radius of 695,508km, compared with Earth’s puny 6,371km. To put it another way, if the Sun were as tall as a door, the Earth would be the size of an oldstyle UAE bronze 1 fils coin.
This year, Nasa announced it was ready to “touch the Sun” – or, at least, to fly a spacecraft closer to the star than any before. This time next year, in a launch window between July 31 and August 19, the Parker Solar Probe will blast off from Kennedy Space Centre to spend the next seven years undertaking seven fly-bys of Venus, gradually shrinking its orbit around the Sun.
By December 2024, it will pass within 6.3 million kilometres of the Sun – seven times closer than any craft has done before and enduring previously unexperienced levels of heat and radiation – collecting new data on solar activity and making “critical contributions to our ability to forecast major space-weather events that impact life on Earth”.
In short, the Sun, long since stripped of the veil of ignorance that concealed its true nature from us for millennia, has become nothing more than another practical fact of life, a god no longer, but a mere cog in the physical machinery of our solar system and the wider universe beyond, that we have come to know and understand so well.
And yet…
As photographs from this week’s total eclipse across the United States show, the double-act of the Sun and the Moon, conducting a rare dance that disrupts our predicted and predictable expectations of sunrise and sunset, still possesses the power to tip back our heads and draw our eyes skyward. Many of the images of people gazing up, transfixed in awe as the Moon transited across the face of the Sun, evoked much earlier times, when for human beings, all was unfathomable mystery and terror.
It isn’t every day that the Sun brings itself to our jaded attention as spectacularly as it did on Monday, when North America experienced its first total eclipse since 1979, as the shadow of the Moon fell briefly across the land in a 112-kilometre-wide band from Oregon in the west to South Carolina in the east.
As millions paused to watch what was probably the most-viewed and certainly most-photographed eclipse in history, “the world appeared to hush for a few minutes as the Moon stood up to the Sun, perfectly blocking its fierce light except for the corona, the halo of hot gas that surrounds it”, reported The
New York Times. “Darkness descended, the summer air caught a quick chill, Venus and some stars appeared in the near-night sky and … humans … were left to hunt for words to describe the spectacle.”
Not for the first time. Though millions of images of this month’s eclipse will have been captured and disseminated on socialmedia sites, the first known representation of an eclipse is thought to have been etched into rock in County Meath, Ireland, at some point between 3300BC and 3500BC. Carvings found on the walls of ancient tombs at Loughcrew are believed to represent a total solar eclipse that would have been experienced in the area on November 30, 3340BC. Deep down, like our ancient forebears, we all know that, as Nasa puts it, “without the Sun’s intense energy and heat, there would be no life on Earth”. Perhaps, an alien anthropologist might conclude, umans prostrating themselves in large groups on hot sandy beaches are doing so in tribute to what must, to them, surely seem to be some kind of deity.
If nothing else, the appearance of the Sun on our eastern horizon every morning and its disappearance in the west every night, serves as a vast, flaming, daily reminder of the limited time span allotted to each of us. If you were to die at the age of 70, your life would be measured out in 25,550 sunrises and sunsets. That’s the sort of unavoidable, metronomic countdown to oblivion that, if considered too closely, is likely to induce debilitating existential angst.
Indeed, perhaps our continuing fascination with the Sun lies in the realisation that, even as it facilitates life, it is a symbol of the futility and ultimately doomed nature of all human existence, whether on Earth or any other planet in our solar system we might eventually colonise.
The really bad news for all life on Earth is that the Sun itself is facing its own event horizon. Our life-giving star is about halfway through its 10-billion-year lifespan, at the end of which it will expand into a giant ball of fire that will consume Mercury, Venus and, most probably, Earth. Though by then we – or whatever we might have become – will be long gone, having learnt the true meaning of “global warming”. As it ages, the Sun is warming up, and scientists believe the Earth will be completely uninhabitable in less than a billion years.
Which is why we should make the most of the spectacle of the solar eclipse while we can. There are three types – partial, in which the shadow of the Moon briefly transforms the Sun into a crescent; annular, in which the edge of the Sun is visible as a ring around the Moon; and total.
Eclipses are relatively common – one kind or another takes place somewhere in the world about five times a year. Even total eclipses are fairly frequent, occurring every two or three years, though on any one spot on Earth they are likely to come around only once every 350 years or so. The next will be seen on July 2, 2019, along a curved corridor starting in the middle of the Pacific Ocean and sweeping across parts of Chile and Argentina.
On December 26, 2019, Abu Dhabi and Dubai, slightly to one side of the central line, will bask in the partial shadow of an annular eclipse, which will be best viewed further up the Gulf in Hofuf in Saudi Arabia. Dubai and Muscat in Oman will have a glimpse of another annular eclipse at about 9.36am on June 21, 2020.
But the next total eclipse that will be viewable from anywhere in the Middle East is 10 years away: on August 2, 2027, the Sun will be blotted out for much of the length of the Red Sea, affecting cities including Jeddah and Mecca in Saudi Arabia and Sana’a in Yemen.
Abu Dhabi and Dubai will have to wait a little longer. The next total eclipse in the UAE, at 1.06pm on September 3, 2081, will be a spectacle for your children, grandchildren and great-grandchildren. A child born next month on September 3 will be treated to a total eclipse in the UAE on their 64th birthday.
It will be the first seen over the UAE since reliable records began at the end of the 19th century – and the next one after that won’t be along until October 7, 2135.