The seven wonders of the solar system

By Brian Cox Published: 7:00AM GMT 02 Mar 2010

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Prof Brian Cox witnessing the 2009 sum solar obscure in Varanasi, India Photo: BBC

When we think of the golden age of space exploration, the minds spin behind to those black and white images of Apollo astronauts, the beeps of Sputnik as it promote from space. Today, space seems something of an afterthought: usually this month, the pressures of the retrogression forced Barack Obama to throw the USs programmed lapse to the Moon. So how, in my new BBC documentary, Wonders of the Solar System, can I explain that "we are vital by the biggest age of scrutiny the civilised universe has known"?

Well, when I was born, in Mar 1968, we had nonetheless to revisit the hulk planets of the outdoor solar system. Jupiter, Saturn, Uranus and Neptune were puzzling balls of gas, with moons that, as far as we knew, were routine balls of rock. These were faraway worlds, glimpsed usually by the lenses of Earth-bound telescopes. We had usually only finished the initial successful interplanetary mission, when Nasas Mariner 2 booster swept over the clouded cover tops of Venus in Dec 1962.

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Today, as I write, Nasas identical tiwn rovers, Spirit and Opportunity, are commencement their sixth year of exploring the Martian surface. The rarely successful Cassini mission, a corner plan in between the US and EU, is returning ever some-more pleasing images from the circuit of Saturn, heading to a host of systematic discoveries. Nasas Horizons booster is en track to the outdoor reaches of the solar system: it is already a billion miles from the Sun, and will arise from the state of hibernation when it arrives at Pluto in 2015, prior to stability outwards in to the puzzling Kuiper leather belt of solidified "ice dwarves" that stretches out towards interstellar space. And maybe majority smashing of all, Voyager 1, the majority faraway synthetic object, is still operative twenty-three years after the launch, promulgation behind gloomy signals, that take some-more than fifteen hours to have the 10-billion-mile tour home, as it searches for the corner of the breeze from the Sun, that would symbol the corner of the solar system.

And whilst these technological achievements are impressive, the new discoveries from these far-flung worlds have the intensity to have an stroke approach over the subsection of the multitude that has a flitting seductiveness in astronomy.

For me, the majority extraordinary headlines from the explorers has been the clever justification for the participation of liquids on the moons of Jupiter and Saturn. Before we visited these gas giants, majority scientists approaching their moons to be rather similar to the own: beautiful, perhaps, but in conclusion dead. It was well known from telescopic observations that Saturns largest moon, Titan, had a unenlightened atmosphere, but at a area of 750 million miles from the Sun, this universe would positively be a solidified wasteland.

This has incited out to be emphatically not the case. On Yuletide Day 2004, the European Huygens examine isolated from Cassini and began the delayed skirmish to the aspect of Titan. Just over dual weeks later, it landed on what appeared to be a dry riverbed, populated with smooth, eroded stones. With the assist of photographs and radio detector interpretation from orbit, Cassini and Huygens detected that there is liquid on the aspect of Titan: clouds from that hulk droplets of sleet boyant by the moons unenlightened atmosphere, stuff oneself streams and rivers that upsurge in to seas far incomparable than Lake Superior here on Earth.

This aspect looks so informed to the eyes; a landscape sculpted by issuing liquid, only as the rain, rivers, and seas carve the aspect of the planet. Yet Titans aspect heat is -180C, far as well cold for liquid H2O to exist. The clouds and seas of Titan are done of liquid methane, a incendiary gas here on Earth. It turns out that Titan has only the right windy heat and vigour to assent methane to exist as a gas, a liquid and a solid, heading to this different landscape on a universe 3 buliding of a billion miles from home.

Liquid methane is one thing, but liquid H2O would be utterly another. Enter Jupiters solidified moon, Europa. Pictures of the surface, and measurements of the captivating margin from Voyagers 1 and 2, and the Galileo probe, that orbited Jupiter until 2003, have reliable that Europa contains an sea of liquid H2O underneath an icy membrane maybe 10 miles thick. The sea is thought to approximate the moon, and be up to 100 miles deep. This equates to that it is expected that there is some-more liquid H2O on Europa than on all the oceans, rivers and glaciers of Earth put together.

This has potentially surpassing implications, since we know from the own universe that wherever there is water, there is hold up even in the darkest caves and on the deep, sea floor, where there is no object and abrasive pressure. If the laws of production and chemistry are universal, requesting from the own solar complement to the majority faraway stars, because should the laws of biology be any different? If the conditions are right, afterwards hold up might well develop and flourish.

And the not only Europa. There is great justification that dual some-more of Jupiters large moons, Ganymede and Callisto, might additionally have large sub-surface oceans. Not to be outdone, Cassini has not long ago detected fountains of ice on the aspect of Saturns little moon Enceladus, erupting hundreds of miles in to space. These ice-geysers are obliged for formulating one of Saturns gloomy but pleasing rings but they additionally indicate the hold up of sub-surface lakes of liquid water. And closer to home, the vegetable gypsum has been found in abounding quantities on Mars, that indicates that there contingency have been large areas of station H2O in the past, that could still be benefaction in pockets underneath the aspect today.

These discoveries all point to a solar complement that is potentially some-more fit to be inhabited at slightest for microbes than we could have presumably imagined. And in my view, this fast maturation design of a diverse, beautiful, visitor nonetheless informed family of worlds orbiting the star should have certain amicable consequences.

For we right away know dual things: first, that we might well be on the verge of finding that we are not alone in the Universe; that hold up might not be singular to Earth. And second, that the solar complement is fragile. The worlds we have visited roughly positively miss the conditions for complex, multi-cellar hold up to evolve, and are unqualified of hosting a civilized world that can set up space probes and try the vast surroundings. All the justification suggests that Earth-like planets might be really rare.

That monument does not consult insignificance, but measureless value. To realize this, though, we have had to tour outwards to the stars. These are the gifts available the explorer: perspective, piety and purpose, and in conclusion a renewed clarity of the worth of home.

* Brian Cox is highbrow of production at Manchester University, and one of the countrys best-known communicators of science. "Wonders of the Solar System" front on BBC Two at 9pm on Sunday.