Astrofest is a two day astronomy conference run by Astronomy Now and held in the Kensington Conference Centre in London each February.
This year’s Astrofest started with a talk by Dr Megan Argo on what happens when galaxies collide. Megan explained that there are a number of things that happen when galaxies collide.
One of the most common effects is the accelerated production of stars. As a result of the dust and gas from the two galaxies crashing into each other the process of star formation, which normally relies on gravity to collapse the dust and gas in star formation regions, is speeded up enormously and the rate of star formation increases drastically. These are called starburst galaxies because of the increased rate of star formation. This is, however, a transient effect, probably lasting for no longer that a billion years. In fact the increased rate of star formation usually starts even before the galaxies collide, once they come within the gravitational influence of each other, which explains the relatively long timescale for this effect. One of the nearest starburst galaxies is M82, which is easily visible with amateur telescopes.
The second effect of Galaxy collisions is the disruption of spiral galaxies and the creation of a merged Galaxy which has lost its spiral structure.
The morning’s second talk came from Marcel Tessenyi who spoke about the proposed Twinkle Mission.
Marcel pointed out that, whilst the cost of space missions continued to increase, the money available for them was actually shrinking. Twinkle is a mission designed to look more closely at exo-planets to see what the make up of their atmosphere’s are which will in turn tell us more about the nature of the planets themselves.
By limiting themselves to only looking at the 100 brightest exoplanets, Twinkle hopes to build using off the shelf components and to launch within three years. Their estimate of the total cost of the mission is £50 million which they hope to raise through a combination of public funds, sponsorship and commercial exploitation of the data the mission will collect. In particular they hope to sell some of the mission time to countries which do not themselves have a native space capability. If things go to plan they hope to launch at the end of 2018 or the beginning of 2019.
The morning’s third talk came from Haley Gomez from Cardiff University.
Haley pointed out that Galaxies are suffused with dust but that we do not know where most of it comes from. The prevailing theory has been that relatively small stars create dust when they die in the form of the Planetary Nebula they blow off, whilst supernovae have been seen as destroyers of dust as a result of the violence of their explosions. There are two problems with this however.
- Firstly small stars do not produce anything like enough dust to produce what we see today
- Secondly they take too long to do it. Stars like the Sun last for billions of years yet dust has been seen in the early Universe only a few hundred million years after the Big Bang. So where did it come from.
The emergence of Infra Red astronomy over the last 30 years and in particular the launch of the Herscell space telescope has opened up the possibility of looking again at supernovae. What was found was surprising but a little confusing. Some, but not all, supernovae produce dust. But the ones which do, produce it in prodigious quantities. So for example the supernova SN1987A has already produced enough dust to make half a million earths. Cassiopeia A has produced massive amounts of dust but Tycho’s supernova appears to have produced none at all. So supernovae seem to be responsible for a significant amount of the dust in the current Universe. Whether they account for all of it remains an open question.
The morning session wound up with a very entertaining talk from Matt Taylor on the Rosetta mission and a brief talk by Garek Isrealian and Brian May on the 2016 Starmus festival which will be held on Teneriffe at the end of June.