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South Africa, Australia and New Zealand will share the hosting of the Square Kilometre Array (SKA), which will be the largest radio telescope ever built. The array will be made up of thousands of antennas extending out a distance of at least 3000 km from a central core. The use of a large spread of smaller antennas mean that the telescope will have a very large field of view and high sensitivity, and will be a revolution in astronomical capability. The headquarters for the project team for the SKA is based at Jodrell Bank, which the ESERO-UK team visited this month. The Lovell Telescope, at Jodrell Bank, was built in 1955. It was the largest telescope of its day, and, at 76m in diameter, is the third largest dish in the world today. The Lovell Telescope is now part of a worldwide network of radio telescopes, which by around 2022, will include the SKA.

So how is using lots of small radio telescopes better than using one big one? For a single dish, the radio waves reflect off the large surface and are focussed at a central detector in the middle of the dish. An array uses multiple detectors spread out, and combines the signals electronically – this requires much more processing but gives better results.

Five key science objectives have been identified so far:

• Investigating galaxy evolution, cosmology and dark energy
  
• Searching for gravitational waves using pulsars and black holes
  
• Cosmic magnetism – the study of interstellar magnetic fields
  
• Searching for life and planets
  
• Studying the first luminous objects in the universe
  

The SKA Telescope homepage gives a more detailed explanation of the science behind each of these goals, and the improvements that the SKA should make to our understanding.

The European Southern Observatory collection on the eLibrary contains videos on other important telescopes, such as the VLT and ALMA. The Royal Astronomical Society collection has resources for teachers on cosmology and astronomy in the UK. The Astrophysics: 16-19 group, in our community pages, has an excellent presentation by Dr. Charles Barton, on Cosmology, Hubble’s Law, The Big Bang and Dark Energy.