Cassini Farewell

So many topics to consider for a column. Perhaps something of great importance like the standoff of two crazy guys both armed with nuclear weapons one of whom could make one silly decision and irrevocably change the world for ever. Not for the better.
Or how about the latest instalment in our own election? Winston Peters, the politician so adept at receiving leaks and then demanding accountability and transparency hoisted by his own petard. He may have been claiming more from the tax payer than he was entitled joining a long list of dodgy dastardly dirty double dipping politicians but immediately able to play the wronged to full effect as he hunts out the leaker.
Could it be someone in the National Party using the powers of government to retain power or a civil servant upset by the double standard of Turei falling on her sword over her own benefit fraud and Peters remaining unscathed?
Or some other diabolical leaker. Who knows? Who cares?
No, this week we want, indeed need something uplifting. Something to remind ourselves that our species can be damn clever. Something to lift our sights above the humdrum of daily reality and politics. Let us look skywards to the stars, or at least to the planets.
One in particular; Saturn.
The Cassini space probe will finally finish its epic mission on the 15th September when it slams into the planet it has faithfully pictured, probed and examined from every angle for 13 years.
This magnificent feat of human accomplishment showed that we humans can indeed co-operate as NASA, The European Space Agency and some help from the Italian Space Agency all contributed. They began talking about the concept way back in the early 1980’s.
Cassini was launched in October 1997 and just to get to Saturn used gravity assisted slingshot flybys to increase speed of Venus twice, then two years after launch the earth itself and finally giant Jupiter arriving in the Saturn system on the first of July 2004.
Just consider the maths and physics required to get it from here into the orbit of Saturn then fly closely past without hitting various moons and the rings over its 20-year life span. The planet itself is 1.4 billion km from the sun or 9.5 times further from the sun than us.
Saturn has a radius nine times bigger than the earth and being a gas giant is only one-eighth of the density but still 95 times more massive.
Before Cassini arrived, there were 58 known moons but the spacecraft has discovered another 4.
And of course, there are the rings. They extend 6000 km from the planet out to 120,000km but are only 20 meters thick. Made up of 93% ice and the balance is carbon. They reflect the sun’s light back to us and can be seen in a small telescope.
In 1610, Galileo mistook them for moons in his rudimentary telescope so it was left to Huygens with a better telescope to see the rings and discover Titan, the largest moon consisting of 90% of all the mass that orbits Saturn including the rings.
Cassini dropped its probe Huygens in 2005 and in a marvel of precision and physics it then landed on Titan, making it the greatest distance from the earth that a spacecraft has settled.
Cassini has created a wealth of information on the Saturnian system and it is difficult to pick highlights.
One would have to be the findings about the moon Enceladus. Covered in fresh clean ice, it is one of the most reflective bodies in our solar system.
Cassini has had several close flybys and discovered active geysers emitting water, salts, nitrogen and organic molecules coming from a hydrothermal active interior. Exactly the sort of environment where we see microbes living here on earth.
Enceladus is an excellent candidate to prove that there is life somewhere else in the universe other than earth and that the universe is likely teeming with other life forms.
Which is why Cassini is being flown to its destruction into Saturn as its power supplies dwindle rather than left to orbit the system for eternity. There is an outside chance that earth microbes still cling to the craft and should it eventually smash into Enceladus or another moon with native life forms, our microbes could contaminate them much as Europeans did as they explored the world and met endemic peoples.
Take the kids out this month to see the ‘star’ of the show. Looking directly up mid evening near Antares the red heart of the Scorpion you will see bright Saturn with its yellowish hue. The Scorpions tail of the ancient Greeks was known as the fish hook of Maui by the Maori.
The Roman god Saturnus by the way was the god of agriculture.
Then show them the wonderful images taken by Cassini of Saturn, its rings and planets so accessible on the internet.
Very, very cool.

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