(c) Taking the Friedmann equation without the Cosmological Con- stant: kc2 à? a2 8AGP 3 a2 and a Hubble constant of 70 k

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C Taking The Friedmann Equation Without The Cosmological Con Stant Kc2 A A2 8agp 3 A2 And A Hubble Constant Of 70 K 1 (98.26 KiB) Viewed 9 times

(c) Taking the Friedmann equation without the Cosmological Con- stant: kc2 à? a2 8AGP 3 a2 and a Hubble constant of 70 km/s/Mpc, determine the critical den- sity of the Universe at present, on the assumption of spatial flatness. [7 marks] (d) For one of the most distant known galaxies at a redshift of 9.11, we find evidence for stars whose ages are already 300 million years old. This suggests 'first light occurred at a redshift of about 15. i. Making the approximation that the Universe has remained matter dominated, calculate the critical density of the Uni- verse at the redshift of 15. ii. Show that at this redshift the age of the Universe was 1/64 of the present age. [3 marks] [3 marks]