Links 14/12/13

On this day China's Chang'e Lunar Lander successfully touched down on the Moon at 13:11:18.695 GMT (8:11:18.695 EST). It's the first spacecraft to land on the Moon in 37 years. Here's an animation based on images taken by its landing camera during descent.

'NASA’s Hubble Space Telescope has observed water vapor above the frigid south polar region of Jupiter's moon Europa, providing the first strong evidence of water plumes erupting off the moon's surface.'

 'A new analysis of data from NASA's Galileo mission has revealed clay-type minerals at the surface of Jupiter's icy moon Europa that appear to have been delivered by a spectacular collision with an asteroid or comet. This is the first time such minerals have been detected on Europa's surface. The types of space rocks that deliver such minerals typically also often carry organic materials.'

'Cassini's recent close flybys are bringing into sharper focus a region in Titan's northern hemisphere that sparkles with almost all of the moon's seas and lakes. Scientists working with the spacecraft's radar instrument have put together the most detailed multi-image mosaic of that region to date. The image includes all the seas and most of the major lakes. Some of the flybys tracked over areas that previously were seen at a different angle, so researchers have been able to create a flyover of the area around Titan's largest and second largest seas, known as Kraken Mare and Ligeia Mare, respectively, and some of the nearby lakes.' 



'The Curiosity mission has achieved another milestone as scientists have determined that the rocks inside Gale Crater that were analyzed by the rover are very old – even on geologic time scales, but were exposed very recently. The achievement of utilizing in-situ age-dating methods using radiogenic and cosmogenic noble gases marks a first in planetary exploration.' 

Visit National Parks on other worlds.

Cold War Christmas Cards from the USSR.

Five Billion Years Of Solitude

Image courtesy NASA/JPL-Caltech.

On clear summer nights when I was quite young, I used to like to sit out on the lawn in an old chair and look up at the stars. There wasn't much light pollution back then, at the edge of the Cotswolds, so the sky was full of stars. And I'd wonder, as so many do, if a world much like Earth might be orbiting them, and if a boy much like me might be looking up at its night sky, and the insignificant star that was the Sun.

The profound question of whether we are alone in the Universe - if Earth and humankind are unique, or if there are many Earth-like worlds harbouring other forms of intelligent life - is the topic of Lee Billings's Five Billion Years of Solitude. 4.6 billion years after it was formed, Earth sits at the centre of a small expanding sphere of radio noise that might be detected by other civilisations, and astronomers have begun to catalogue a vast variety of exoplanets. Could any of them harbour life? What would it look like if they did? And is there anyone else out there, as lonely as we are?

Billings frames the history of the search for extrasolar planets and plans to search for Earth-like worlds within biographical portraits of planet hunters, from Frank Drake to rising star Sara Seager, who plans to use relatively cheap nanosatellites to monitor single stars for signs of transiting planets. I would have preferred a little more science rather than noveletish descriptions of what Billings's interviewees happened to be doing and wearing when he met them, and because all of them are American the work of astronomers from other countries is somewhat scanted. Michel Mayer, who led the team which discovered the first exoplanet, is given only a passing mention; the work of the HARPS project, a collaboration between a Swiss team led by Mayer and the European Southern Observatory's telescope in Chile, is presented in terms of competition with an American team rather than in its own right.

But these are minor quibbles. Billings expertly anatomises the difficulties in detecting the faint jitters in the motion of stars or the minute dimming in their luminosity that signals the presence of exoplanets, evokes the teeming variety of exoplanets so far discovered and the problems astronomers hunting for Earth-sized exoplanets must overcome.  He's very good, too, on the labyrinthine politics of NASA which have stalled the Terrestrial Planet Finder project, and the ongoing problems with the vastly expensive James Webb Space Telescope, the successor to Hubble. And his entanglement of the lives of the planet hunters with their work reminds us that their discoveries provide us with new and humbling perspectives on our place in the universe and the evanescence of our tenancy on this planet.

The universe is vast, and old. Billings uses the stump of a redwood tree in Frank Drake's backyard to provide a lovely and sobering lesson about deep time. Growth rings show that the tree was more than 2000 years old. During that time

'the Sun had scarcely budged in its 250-million-year orbit about the galactic center, and, considering its life span of billions of years, hadn't aged a day. Since their formation 4.6 billion years ago, our Sun and its planets have made perhaps eighteen galactic orbits - our solar system is eighteen "galactic years" old. When it was seventeen, redwood trees did not yet exist on Earth. When it was sixteen, simple organisms were taking their first tentative excursions from the sea to colonise the land. In fact, fossil evidence testified that for about fifteen of its eighteen galactic years, our planet had played host to little more than unicellular microbes and multicellular bacterial colonies, and was utterly devoid of anything so complicated as grass, trees, or animals, let alone beings capable of solving differential equations, building rockets, painting landscapes, writing symphonies, or feeling love.'

The first confirmed discovery of an exoplanet was made less only twenty years ago. Although more than a thousand have been discovered since then, it's a microscopic sample of the trillions believed to exist in our galaxy. A few are Earth-sized, but none found so far are known to be Earth-like, and we're still a long way from discovering evidence for life on another world, let alone any intelligent beings that might also be searching for traces of other life in the immense sea of stars. 'We're the product of millions of years of evolution,' Sara Seager says, 'but we don't have any time to waste.'

alt.shuttle

NASA's space shuttle programme was started when the Cold War began to grow hot: the first flights took place in the era of Cruise missiles, Protect and Survive, the doctrine of a winnable nuclear war uncovered by Robert Sheer's With Enough Shovels, The Day After, and Frankie Goes To Hollywood's 'Two Tribes'. The Soviet authorities realised that the shuttle had serious military uses, and decided to start their own programme. The spacecraft in the image above, Buran, is the only Soviet shuttle to have reached orbit. Launched in November 1988, it was unmanned, completed two orbits of the Earth, and landed under automatic guidance. There's more information about it here and here.

Within a year, history had overtaken the Buran programme. The Berlin Wall fell, the Soviet Union collapsed, and the authorities realised that their space shuttle was an expensive dead end which could no longer be justified, and shut it down (the USA took somewhat longer to come to the same conclusion). Four shuttles were under construction at the time. One, nicknamed Ptichka (Little Bird), is stored in the Baikonur Cosmodrome alongside a non-flying prototype; another, Baikal, is parked on an airfield; the other two have been partially or completely dismantled. Two  prototypes are on public display: one in Gorky Park, Moscow; the other in the Technik Museum Speyer, Germany.

As for Buran, the only Soviet shuttle to have orbited the Earth, it was destroyed when the roof of the hangar in which it is was being stored at Baikonur collapsed. An ignominious end to the avatar of an alternate history which might have intensified the cold war in low Earth orbit, or which might have seen two kinds of space shuttles servicing the International Space Station, but which otherwise, let's face it, probably wouldn't have been very different to our own history.