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, eventually reaching Neptune at the edge oof the Solar System.
Brian Cox revealed during his BBC series “The Planets” how the probe studied the moons of the planet, noticing it was quite bizaree.
He said last month: “What is happening in the sunlight is falling on the thin layer of nitrogen ice, going through and heating up a layer of darker particles a metre below the surface.
“A difference of just four degrees Celsius is enough for the heat to radiate up and vaporise the frozen nitrogen, creating gas.
“That gas is under pressure and, ultimately, it punches through the nitrogen ice carrying those dark particles up and making the geysers of Triton.
“In the furthest reaches of the Solar System, the faint light of the Sun is still enough to power the most distant of geological wonders.”
However, in order to explain Triton’s biggest mystery, NASA had to think outside the box.
Dr Cox added: “But this can’t explain the rest of Triton’s mysterious features.
“Terrain on this scale could only have been created by a much more powerful force,
“And a clue seems to be lurking in Triton’s odd orbit.
“Unlike every other large moon in the Solar System, Triton orbits in the opposite direction to the spin of the planet.”
Dr Cox explained how the space agency exposed Triton as an alien object to the Neptune system.
He continued: “That means that it’s highly unlikely that Triton and Neptune formed at the same time.
“If you formed a planet and a moon out of the same collapsing cloud of gas and dust, then they tend to spin and orbit the same direction.
“So the most likely explanation is that Triton is a visitor to the Neptunian system.”
Dr Cox also revealed during the same series how Voyager probed Uranus.
He said: “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 the 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.”