TED 2007 starts with a raucous procession of a brass band, dressed in Indian costumes, rasta wigs and the sorts of leather and spikes that Oakland Raiders fans wear. (This helps explain the group of hip looking young men who’ve been standing outside the conference center for the past hour.) I think at least one of the hipsters in question is Thomas Dolby, the resident musical provocateur of the conference.
This year’s theme is “Icons. Geniuses. Mavericks”. Our first speaker is Carolyn Porco, who might well qualify as a genius or maverick (and, if she appears at a few more conferences, as an icon.) She’s an expert on planetary rings and has served as the leader of imaging of the Voyager and Cassini space missions.
The focus of her talk today is some of the amazing discoveries that have come back from the Cassini mission to Saturn, one of the missions to the planets – “all eight of them” as well as “the body formerly known as Pluto”.
Cassini entered orbit around Saturn in 2004, becoming the furthest-flung robotic robotic observation station. The images that the probe has sent back are extraordinary – tiny moons in the shadow of a collosal planet, the thin sliver of the rings seen on edge.
Porco is most fascinated by exploring the moons of Saturn, notably Titan and Enceladus. Titan is the largest moon of Saturn and, prior to Cassini, was the largest unexplored terrain in the solar system. The moon is fascinating to scientists because it has a deep, thick atmosphere made of organic chemicals – methane, propane, ethane. The temperatures on the surface of the planet are roughly -350 Farenheight, cold enough for methane to behave as a liquid. “Methane is to Titan what water is to earth”, she tells us. The conditions on the surface are such that there can be rains of methane, carving gulleys and canyons, pooling and falling in cataracts.
Because the haze is so thick, it’s been very hard to image the planet from outside the atmosphere. The key breakthrough has been the Huygens probe, a project of the European Space Agency which is “the first device of human making that landed in the outer solar system.” Porco literally gets teary when she talks about the device, saying that the landing, “should have been celebrated with tickertape parades in every city in the US and Europe, and sadly that was not the case…”
As the probe descended (taking 2.5 hours to pass through the atmosphere), the cameras on the Huygens probe show clear evidence of a “dendritic drainage pattern”, with rivers of methane draining into lakes and oceans. The images, taken from eight kilometers high, are stunning, and look clearly Earthlike, clearly like a shoreline.
Huygens landed in a “mudflat” of semi-solid ground on top of a sea of methane. Porco shows a lovely panorama of “sand dunes” taken by the probe, circling the “tropics” of the planet.
More amazing is Enceladus, a much smaller moon, about the tenth of the size of Titan. She shows Enceladus as if it were hovering over Britain (it’s not a threat, she promises” – the moon is roughly the size of England and Wales. It’s got a white, fractured surface lined by geogolical and tectonic activity.
The amazing part of Enceladus is the South Pole, where these white canals are lined with green – they’re much warmer than the rest of the planet and are rich in organic material. There are jets of fine icy particles flowing out in space, feeding a plume that goes thousands of miles into space above the surface of the planet. These jets suggest that there’s liquid water under the ground on Enceladus, which leads to a planetary trifecta – excess heat, liquid water and organic material, which could be an environment suitable for living organisms.
Porco ends with an extraordinary image – a total eclipse of the sun from the other side of Saturn. What’s most extraordinary, in my mind, is that the haze around the rings comes from those icy particles coming from Enceladus, particles that might represent liquid water, the potential for life, and the strong chance that there could be lots of worlds in the galaxy capable of supporting life.