ASTR 350: Intro to Cosmology - Understanding the Inflation Theory - Prof. Benjamin D. Wand, Assignments of Astronomy

Download ASTR 350: Intro to Cosmology - Understanding the Inflation Theory - Prof. Benjamin D. Wand and more Assignments Astronomy in PDF only on Docsity! Benjamin Wandelt ASTR 350 – Intro to Cosmology ASTR350: Intro to Cosmology Session 38 Benjamin D. Wandelt Benjamin Wandelt ASTR 350 – Intro to Cosmology Logistics ● Final projects due Monday. – I created an assignment on Illinois Compass ● One more problem set to come – will post during break. You will have 10 days to finish it. Benjamin Wandelt ASTR 350 – Intro to Cosmology A large smooth Universe from a frothy one ● Imagine we could get a patch of spacetime to go through a period of expansion while keeping the density constant. ● The patch would stretch out. The local curvature would decrease at constant density – we would approach flatness. ● Where have you seen this before? How do you get exponential expansion? What type of material (what w ) do you need? Benjamin Wandelt ASTR 350 – Intro to Cosmology Inflation ti m e, e xp an si o n Benjamin Wandelt ASTR 350 – Intro to Cosmology Inflation solves flatness problem ● If the universe expands with constant density (or actually any density that decreases any slower than 1/a2, it approaches flatness. ● Can see this easily from the Friedmann equation – see blackboard discussion Benjamin Wandelt ASTR 350 – Intro to Cosmology Structure formation ● One of the surprising features of quantum gravity: event horizons have a quantum mechanical temperature. This temperature leads to quantum fluctuations. These quantum fluctuations convert to real density fluctuations after being stretched beyond the event horizon. ● The size of the event horizon is c/H. Can you turn that into a temperature by dimensional analysis? Hint: length->time->frequency->energy->temperature Benjamin Wandelt ASTR 350 – Intro to Cosmology Have a nice thanksgiving break!