The sun is the star at the centre of the Solar System – a perfect sphere of hot plasma that is the most important source of energy for life on Earth. Roughly three quarters of its mass consists of hydrogen and the rest is mostly helium. Though it has not changed dramatically for more than four billion years, NASA scientists believe the Sun is roughly half way through its life cycle.
It currently fuses about 600 million tonnes of hydrogen into helium every second, converting four million tonnes of matter into energy every second as a result.
However, Brian Cox warned during his BBC series “Empire of the Sun” what could happen in the future.
He said in 2010: “The sun will spend most of its life on the main sequence, steadily burning its vast reserves of hydrogen fuel that will last for at least another five billion years.
“But eventually, the fuel will run out and its core will collapse.
“Then something remarkable will happen.
“The sun’s outer layer will expand and its colour will shift.
“Mercury will be little more than a memory as it is engulfed by the expanding red sun.”
Dr Cox explained how the Sun will expand to become a red giant and swallow everything in its path.
He added: “It will grow to 200 times its size today, stretching all the way out to the Earth’s orbit where our own planet’s prospects are dim.
“The wonder that has remained so constant throughout all of its ten billion years of life will end its days as a red giant star.
“For a few brief instants, it will be 2,000 times as bright as it is now but that won’t last for long.
“Eventually it’ll shed its outer layers and all that will be left will be its cooling core, a faint cinder that will glow, well, pretty much to the end of time.”
Dr Cox explained why this could mean the end of life as we know it.
He continued: “And all its wonders, the aurora that danced through the atmospheres of planets of the Solar System, and its light that sustains all the life here on Earth, will be gone.
“But the gas and dust of the dying sun will drift off into space, in time to form a vast dark cloud primed and full of possibilities.
“Until one day, another star will be born, perhaps, with a similar story to tell, the greatest story of the cosmos.”
Yesterday it was revealed how NASA made a “puzzling” find on Neptune during its Voyager programme.
Brian Cox explained during his new BBC series “The Planets” how violent storms were spotted on the surface.
He said last month: “Over the years, we’ve observed more storms raging on the planet.
“It’s one of the great mysteries of planetary exploration, why a planet so far from the Sun, with so little energy falling into its atmosphere from sunlight, can have the most extreme winds in the Solar System.
“Yet Voyager made yet another puzzling discovery.
“Although further from the sun, the planet is warmer than Uranus.
“The source of this extra heat remains a mystery.”