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4 October 2007

Happy Birthday Dear Sputnik and No Sultan's Turret?

The meeting on this historic date was well attended - 52 members, 2 new members and 11 visitors. As usual, people arrived a bit before the meeting and few interesting conversations were had. Committee members were on hand to help visitors. Peter sold a total of 29 copies of Skywatcher. John and Paul set up for their respective talks.

Different from other meetings, there were two main speakers at this meeting. John Axtell (Secretary) and Paul Daniels (GAS member).

John was up first. And what an auspicious date! The meeting fell exactly on the 50^th anniversary, to the very day, of the launch of Sputnik 1. There can't be many astronomical society meetings that have started and ended with a song, but this one did! At the start of his talk John suddenly produced a round birthday cake to represent Sputnik but instead of antennae it had sparklers. These were lit while John led everybody in "Happy Birthday Dear Sputnik", the title of his talk. Not in keeping with the norm, the talk was much more than just a dry history lesson on Sputnik. John started off by describing the social situation at the time, covering from the artists of the day to international politics, and mentioning several other 50^th anniversaries celebrated this year, such as bubble-wrap, the laser and the Frisbee!

He went on to describe how Sputnik was built in the hard-to-believe period of a month. Korolev, the Chief Designer, had to fight to convince his superiors to even allow them the one rocket to launch Sputnik. After a successful launch, the news was kept quiet in the Soviet Union. It only made headlines there once the Soviet leader realised how much of an issue it was in the West. Sadly, Korolev and his colleagues never received the honour they were due. His name was only made known to the West years after his death. John detailed the effect that the Soviet success had on the American psyche, a real body blow that eventually galvanised the US.

The Americans had several competing programs that, eventually, could each have lead to a satellite. However, political decisions prevented America from orbiting the first satellite. Immediately after the launch of Sputnik they attempted several launches each ending in ignominious failure, ridiculed by the world press by derisive terms such as "flopnik". As the American rockets were based on either scientific sounding rockets or missiles derived from the principles of the V2, they did not have the same lifting capability as the Russian R7. The Russian rocket was the world's first ICBM, developed to deliver a nuclear warheads weighing several tons. The eventual American satellites (Explorer 1 and Vanguard) were therefore a lot smaller than Sputnik and later Soviet satellites.

It was a very interesting and colourful talk. John finished in light-hearted manner. He told us about a record released later in October 57 by The Goons to commemorate Sputnik and poke fun at the US, called "The Russian Love Song". He took us through several of the lines and jokes from the song, wearing appropriate hats to illustrate the various Goon characters. These ranged from a Russian fur hat through to Britain's answer – a rocket-driven Union Jack bowler hat!

Paul was up next with a talk entitled "No Sultan's Turret?". The title is based on a quotation from Omar Kyam's Rubaiyat about a shaft of light striking the Sultan's Turret:

He showed us an almost magical universe where sunlight affects the orbits and rotation periods of asteroids. This universe is, of course, the one we live in. The effect has been known to exist since around the beginning of the 20th century when Yarkovsky first wrote about it. Yarkovsky realised that infrared photons radiated from a heated object, carry momentum. This momentum causes a pressure to be applied to the body they are radiated from. This became known as the Yarkovsky effect.

A body is heated by the sun. As the body rotates, the heated is radiated, but offset from the direction it was received from. This causes a very small 'thrust' that changes the orbit of the body by a small amount. Unfortunately it is of very small magnitude and it has not been possible to measure the positions of asteroids accurately enough to determine the existence of the effect.

The YORP effect is a variation on the Yarkovsky effect. The infrared radiation causes the the rotation period of a body to change.

This was another interesting talk on a subject that still seems a bit strange, even though there is no real 'magic' behind it. The effects were demonstrated by stunning animations and graphics that clearly took a lot of work to create.

The Sputnik birthday cake was cut up and consumed during the break. Afterwards the meeting was concluded with the monthly observing report and "What's Up" from John.

After the meeting, about 20 of us set off to the pub for a pint and a chat.