Category : Cambridge Astronomy Association

Hot Results on Cool Galaxies by Robert Kennicutt

Last night was the 50th anniversary meeting of the CAA in Cambridge and as well as the Mayor of Cambridge attending we also had Professor Robert Kennicutt as our guest speaker.

His talk was entitled “Hot Results on Cool Galaxies: The Hidden Universe Revealed.” Robert Kennicutt is the Plumian Professor of Astronomy and Experimental Philosophy at the University of Cambridge and the Director of the Institute of Astronomy.

The talk was very interesting and Professor Kennicutt started off by talking about William Herschel’s experiment which discovered that there was heat beyond the visual spectrum of colour and into the infrared.

We were told that most IR radiation is blocked by the Earth’s atmosphere, and that viewing objects in space in the Infrared from ground telescopes is also very difficult, as everything around the scope glows. This has meant that the best way to conduct IR experiments is from space.

Some of these IR telescopes include the IRAS in 1983, ISO from 1995 to 1998, Akari from 2006 to 2007 and the Spitzer telescope from 2003 to 2009.

Professor Kennicutt also took us through various findings of a Spitzer survey (SINGS) and then told us about the new Herschel telescope with it’s 3.5m silicon mirror as well as the Planck microwave satellite which are going up into space together at the same time via an Ariane 5 rocket.

Stars in their Death Throes by John Eldridge

This month’s CAA talk was entitled “Stars in their Death Throes” by John Eldridge. John went over the life span of stars and how they go nova.

He mentioned that Supernova give off enough light to be seen for about 4 to 5 months, such as supernova 1987A and supernova 2003gd in M74.

When stars are born they are hot and blue in colour and are made of helium and hydrogen. At this point other gas and dust is blown away.

The Red Supergiant then gets a carbon oxygen core and then an iron core is created, the centre is then hotter and denser than before. After this the star then collapses down to  a supernova, at which point nickel is produced. 

We were also told that Betelgeuse is actually a Red Supergiant, so think of that next time your are observing it.

The talk about Supernova was very in-depth and quite complicated for me, and I was lost at some points, but none the less a very good talk with lots of good movies of the life span of stars up to the point when they go nova.

The History of Spaceflight by David Bryant

On December 19th I attended the Cambridge Astronomy Association Christmas talk, which was entitled The History of Spaceflight by David Bryant. The CAA also laid on Christmas cake to have with our teas and coffees and we also had an annual competition/quiz where we had to guess what 15 strange objects were used for. I found these difficult to guess, but after hearing the actual answers I think I could have actually won as most of my guesses were correct, nevermind there is always next year!

David gave a personal insight into the history spaceflight. He showed us lots of photos of himself together with many famous astronauts, including ten Apollo astronauts of which seven have visited the Moon.

David started by talking about the history of rockets including the use of rockets by the Chinese Mongols in the 13th Century and the Congreve Rocket in 1805.  He also discussed how rockets work, such as how liquid fuel and liquid oxidizer are pumped together.

He also mentioned the v2 and A4 rockets of World War II and how gyroscopic guidance was introduced. Werner Von Braun was said to be a major influence in US missile design in the 1950’s and 1960’s including working on the Redstone and Saturn rockets. It was also mentioned that Sergei Korolev turned the v2 rocket into the R7 rocket.

David’s presentation was good as it included a lot of video content of shuttle and rocket launches. It was good to learn all about the various NASA launches that have been made.

Overall, David was a very interesting speaker and very funny as he told lots of jokes, a speaker I would like to hear more from.

“Colouring the Night Sky” Talk by Alan Aylward

Tonight’s talk at the Cambridge Astronomy Assocation was by Alan Aylward who was telling us everything we needed to know about aurorae.

Aurora can actually be seen from space, and some images demonstrated this, with views from the NASA shuttle. Aurora were actually treated with fear in historical times.

Aurora OvalEarly research showed that aurorae actually extended around the poles of the Earth in a ring ~(as shown in the accompanying image), and the ring (more commonly called the “aurora oval”) does actually move, so depending on where it is, you may see an aurora.

Aurora’s have actually been visible from the UK, and we were told that in the UK we may have the chance to see aurora up to three times a year, but cloudy nights decrease our chances of viewing one.

The Earth’s aurorae are actually triggered by the Sun, as the solar winds interaction with the magnetosphere is mapped down into our atmosphere. We were also informed that there are different colours to the aurorae. A red aurora means that the aurora is very high in the atmosphere, whilst the middle height colour is green and a low aurora provides a purple colour in the sky.

We were told that Coronal Mass Ejections (CME’s) create the Earth’s aurorae activity, but other planets also have aurorae including Jupiter which creates its own aurorae with a lot of help from the volcanic moon Io. Saturn also have aurorae as well, but they are 100x less active than Jupiter’s.

Overall we learnt, that anything with magnetic fields has aurorae. This was a great talk that told us everything we wanted to know about aurorae, and even more besides.

Impact Day 2008

On Sunday I visited the Cambridge Astronomy Association for the Impact Day 2008, which was a free day of lectures about comets and meteorites.

As well as a full day of lectures there were also a number of stalls selling astronomy books, astronomy hardware and of course a number of meteorites. I was amazed to see the actual number of meteorites that you could purchase, which included rock from the Moon and from Mars.

There were lots of activities for children, including making model craters and the children also received their own iron meteorite for a small fee.

I attended three of the five talks during the day. The first one was by Dr Caroline Smith who was from the Natural History Museum in London, and she looks after nearly 2,000 meteorites in the national collection. We were told that there are over 35,000 meteorites found so far, and that 34,000 of these have come from the Antarctic. The desert of the Antarctic is a great place to find meteorites as they stand out so well in the snow and the dry conditions enhance the preservation of the meteorites, as in a normal country within 20,000 years a meteorite can breakdown and disappear.

We were also told that meteorites can give us the age of the solar system and details on the evolution of the solar system.

It was interesting to find out that stony meteorites are broken down into two groups; achondrites and chondrites. Achondrites have undergone melting whilst Chondrites have not. It was also mentioned that Calcium Aluminium Rich Inclusions (CAI) allow you to date the meteorite.

I also attended a talk entitled “Do you come here often? Dirty snowballs: Comets” by Jonathan Shanklin and a talk by Nik Szymanek, which unfortunately I had seen before, but it was worth sitting through it again, I can’t get bored of seeing Nik’s astrophotography images.

Overall it was a great day, and even better it was all free.

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