Nasa's New Horizons space probe yesterday flew past the outermost "planet" of the solar system, Pluto, at 14km per second a mere 9977km from the surface. The signals carrying the first images from the flyby are still on their way to Earth.But Nasa scientists already know that, instead of being a dark grey icy planet as has long been surmised, Pluto looks more like Mars, with a red hue caused by oxidisation on its surface.And, controversially, Nasa administrator Charles Bolden says he still believes that Pluto is a planet."We're calling Pluto a planet, but technically it's a dwarf planet. I call it a planet, but I'm not the rule maker."It's a big day for Nasa. The US today has become the first nation to visit every planet in our solar system," Bolden said."I expected to see some cold, grey, icy planet but it has a reddish tint, not unlike Mars."Geologists are reportedly marvelling at the colour and will expend much research time and money on explaining it.When the probe did its flyby it carried a sample of the ashes of Clyde Tombaugh, the amateur astronomer who discovered the dwarf planet back in 1930, when he was 24.Tombaugh's achievement is a reminder of the huge importance of "young and amateur backyard astronomers", said Wits University astrophysicist Andrew Chen."Objects out there seem inaccessible and we hear about big survey projects like the Square Kilometre Array, but important discoveries are made all the time by young astronomers, even amateurs."Chen said that ordinary people who watched the skies were "an invaluable resource".Tombaughwas asked by an observatory in Arizona to help search the skies for a planet suspected to be orbiting beyond Neptune.When he found Pluto, after reportedly scrutinising well over a million images captured by the observatory, scientists began to consider the possibility that there were thousands of other icy objects in the Kuiper Belt, a region that begins beyond Neptune.Now, 85 years later, New Horizons is investigating not only Pluto - which recently lost its status as a planet and was reclassified as a dwarf planet - but its five moons, too.The SA Astronomical Observatory's head of instrumentation, Amanda Sickafoose Gulbis, said: "These images from New Horizon represent a whole new frontier in human exploration. This is the first time we have sent a spacecraft to an object in the outer solar system."She said that since Pluto was discovered "the best images we had were a few blurry pixels" but now "New Horizons is giving a face to this dwarf planet and returning ground-breaking scientific information". Additional reporting by © The Telegraph..