ASTR 1102 Lecture : Lecture38
Document Summary
Picture of the day: the history of the universe. You could go around the universe and return home! The universe is very close to flat. Energy density of universe is just right. Matter (+ dark matter) can only account for 27% of critical energy density. Dark energy (= cosmological constant?) works against gravity. In einstein"s picture it balanced gravity static universe. In expanding universe, dark energy accelerates expansion. Distant galaxies would appear to recede slower. Type ia supernovae show this 2011 nobel prize! Acceleration due to dark energy gets weaker. Dark energy acceleration works as it does now. Stars die, star formation exhausted, black holes continue to grow. Eventually clusters, galaxies, stars, even atoms torn apart. Most scientists confident that there is (at most) one intelligent civilization in our solar system. Improbable in dense environment - other stars disrupt planet formation. The solar system took 4. 6 billion years to produce intelligence.
