Real time cosmology - A direct measure of the expansion rate of the Universe

Understand

In recent years cosmology has undergone a revolution, with precise measurements of the microwave background radiation, large galaxy redshift surveys, and the discovery of the recent accelerated expansion of the Universe using observations of distant supernovae.

• In this light, the SKA enables us to do an ultimate test in cosmology by measuring the expansion rate of the Universe in real time.
• This can be done by a rather simple experiment of observing the neutral hydrogen (HI) signal of galaxies at two different epochs.
• The signal will encounter a change in frequency imprinted as the Universe expands over time and thus monitoring the drift in frequencies will provide a real time measure of the cosmic acceleration.