In 1977, NASA launched its Voyager programme to employ two robotic probes – Voyager 1 and Voyager 2 to study the outer Solar System. Scientists calculated the date of a rare phenomenon that meant all the planets furthest from the Sun were perfectly aligned. This allowed the Voyagers probes to whizz through space at a rate of knots, pulled by the gravity of the planets.
Voyager 2 arrived at Jupiter in just under two years, before it was catapulted deeper into space by the large gravitational pull.
Brian Cox revealed during his BBC series “The Planets” how the huge planet managed to give it one final push, and discover a new planet.
He said last month: “Almost nine years after leaving Earth, Voyager approached an entirely new class of planet.
“Just like Jupiter and Saturn, the planet’s upper atmosphere is composed of mostly swirling hydrogen and helium gas.
“And hidden beneath lies an exotic, icy mix of methane, ammonia and water.
“But unlike the other gas giants, Uranus is almost featureless.”
Dr Cox went on to explain why Uranus was like nothing NASA had seen before.
He added: “For all the time that Voyager stared at the planet, it saw ten cloud formations.
“And we soon discovered why.
“Uranus, at -224C is he coldest planet in the Solar System – the first of the ice giants – in a permanent state of deep freeze.
“Voyager spent just six hours with Uranus and as its gaze widened, it took in the entire system.”
Dr Cox also went on to reveal how the planet had one last surprise.
He continued: “Just like Saturn, Uranus has rings.
“The rings are so dark, so faint, that they’re very difficult to see from Earth.
“They must be made of some kind of material that doesn’t reflect a lot of sunlight back, and we don’t know what that is yet.”
During the same series, Dr Cox also revealed Saturn’s rings were much younger than previously thought, thanks to NASA’s later Cassini mission.
He said: “By measuring the way the dust from the Solar System falls on to the rings, Cassini made a startling discovery.
“If the rings have been around Saturn for billions of years, they should have been darkened and dimmed by the dust.
“But they are pristine and bright and the reason is because they are young.
“Nearly 4.5 billion years younger than Saturn itself.”
