21st April Lecture: DESI – the Dark Energy Spectroscopic Instrument.

The expansion history and large-scale structure of the Universe is a key prediction of cosmological models, and DESI observations will permit scientists to probe diverse aspects of cosmology, from dark energy to alternatives to General Relativity to neutrino masses to the early Universe.

DESI will measure the expansion history of the Universe using the baryon acoustic oscillations (BAO) imprinted in the clustering of galaxies, quasars, and the intergalactic medium and will extract cosmological distance information from the clustering of matter and galaxies.

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17th March Lecture: Seeing through telescopes large and small.

Images of astronomical objects from ground-based telescopes are blurred by turbulence in the earth’s atmosphere – a phenomenon referred to as “seeing”.

The magnitude of the effect depends on the strength of the turbulence, the size of the telescope and the wavelength at which observations are made.

This talk will discuss how the earth’s atmosphere affects ground-based telescopes of all sizes, how the turbulence strength is measured and some of the methods that can be used to ameliorate its effects.

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17th February Lecture: The promise of gravitational wave astronomy.

Gravitational waves offer a new way to uncover the universe.

General relativity suggested their existence, but even Einstein wasn’t sure about them. It wasn’t until the 1970s that there was evidence of their existence, but it took 40 years to be able to detect them.

Now we can detect these ripples in space time, what do they tell us about black holes, neutron stars and the fundamental nature of the universe?

There are many wonderful images (public domain) at the LIGO website https://www.ligo.caltech.edu/images

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