Astrofest 2014 – Session 2

The second session started with a talk by Mark McCaughrean of the European Space Agency on ESA’s Space Science programme.

Is there water under the surface of Mars? What does the Milky Way look like in 3D? What is the Universe made of? Did comets deliver the raw materials of life to Earth. These are some of the questions the ESA has set out to answer.

Mark started by pointing out that we live in a world which is hugely dependent on science and technology and yet one in which very few people actually understand what science and technology is and what it does. Part of ESA’s job is not only to make discoveries but to try to ensure that information about those discoveries is made avaialble to as many people as possible.

He then talked briefly about four projects that ESA has either run or been involved in. 

The first was the Hubble Space Telescope which is 15% funded by ESA. Hubble is probably the most famous scientific instrument ever and has been involved in more discoveries than can be counted as well as producing most of the most iconic photographs of the Universe ever.

Where Hubble worked in visible light the Herscel telescope worked in infrared which enabled it to look at the Universe in an entirely different way. In visible light dust obscures but in the infrared it lights up and showsstar forming areas in ways that cannot be seen in visible light. Some of the images of, for example M31, in infrared are spectacular.

The Planck mission by contrast has enabled us to look back in time to the early days of the Universe and measure the cosmic microwave background and from that determine the proportions of ordinary matter, dark matter and dark energy in the Universe.

The next part of the talk dealt with the Giai mission which will accurately measure the position of one billion stars over a period of 5 years to produce the most accurate star catalogue ever. Giai will, amongst many other things provide a real insight into the formation and evolution of the Galaxy as well as the role of dark matter and the physics of many types of stars.

Finally he dealt with the Rosetta mission which is due to land on comet 67P later this year. Since it seems likely that comets were responsible for bringing the raw materials of life to Earth there are great expectations for the information Rosetta may unearth.

The second talk of the afternoon came from Al Nagler who talked about his work in designing the optics for the Apollo training centre and how the lessons learnt there transferred into the high quality astronomy optics his company are now justly famous for.

The next talk came from Paul Crowther of the University of Sheffield and concentrated on the largest stars we know of. Whilst stars come in all sizes, the smallest can fit within the M25 whilst the largest, if put in the position of the Sun, stretch out to the orbit of Saturn it is these Monster Stars that the talk concentrated on.

Paul pointed out that the largest stars by size tended to be cool supergiants whereas the most massive stars were hot and luminous with temperatures of up to 50,000 degrees and up to nearly 10 million times more luminous than the Sun.

These massive stars form quickly in around 100,000 years as opposed to the 10 million years for the Sun, only live for a short time – a few million years at most and probably end their lives in super luminous supernova much brighter than normal supernovas.

The most massive stars currently being studied are Eta Carinae and the three stars of the R136a group in the Tarantula nebula, a part of the Large Magellanic Cloud which, unfortunately, is not visible from the northern hemisphere.

Thats it for day one of Astrofest. I’ll post some more reports from tomorrows sessions.

 

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