PHYS 005 Lecture Notes - Lecture 19: Virtual Particle, Supermassive Black Hole, Saul Perlmutter
5 Jul 2018
School
Department
Course
Professor
5/18 Session 19 (Session 21)- Dark Energy and Gravitational Waves
Ch. 26 Sect. 7
Calculating redshift
**LOOK AT TABLE
https://ilearn.ucr.edu/webapps/blackboard/execute/content/file?cmd=view&content_id=_3224301_1&
course_id=_268211_1
Slide 2
1000 x closer doesn’t really matter
Why do we add 1 to z?
Dark Energy
Combined mass density po (matter + energy) of Universe is
Po= pm + prad
Value- > 1, = 1, <1- determines curvature of universe when comparing P,o with Pc
●Flat = 1
○Not enough mass/radiation for this to happen
We came to conclusion that dark energy exists bc
●Lack of things in universe that make it flat
○Dark energy EXPANDS universe & KEEPS IT FLAT (76%)
■Accelerated rate of expansion
■Keeps light beams parallel
Supernovae (Type 1a)
●Helped come to this conclusion
○Always reaches the same peak brightness
■Dimming only due to distance
■Calculate redshift
Goes against Hubble Law
●ACCELERATED EXPANSION instead of linear expansion- Hubble
○Needs 76% of unvierse to be dark energy in order for this to happen
●Saul Perlmutter received Nobel Prize
●Always expands @ the same speed
●Expands faster every second CORRECT
○Gravity will not win- everything will be ripped apart
5 different ideas of what dark energy is
Document Summary
5/18 session 19 (session 21)- dark energy and gravitational waves. Combined mass density p o (matter + energy) of universe is. Value- > 1, = 1, <1- determines curvature of universe when comparing p ,o with p c. Not enough mass/radiation for this to happen. We came to conclusion that dark energy exists bc. Lack of things in universe that make it flat. Dark energy expands universe & keeps it flat (76%) Accelerated expansion instead of linear expansion- hubble. Needs 76% of unvierse to be dark energy in order for this to happen. Gravity will not win- everything will be ripped apart. 5 different ideas of what dark energy is. Looking at the graph, wherever blobs intersects is where things happen. What is dark energy: energy exists in universe as it expands- a characteristic of space. After big bang, all matter has already come into existence.
