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Announcements• Exam 1 is next time. Will cover The Five Ages of the Universe. 15 to 18 multiple choice questions and 3 essays. I will probably give you a list of 5 to 7 essay questions to choose from.
• For next Monday, read the first two chapters of Foundations of Modern Cosmology
Colored Card Question
During the black hole era the only “ordinary” matter left isa) free protons and neutronsb) electrons and positronsc) hydrogen and heliumd) None of the above, there is no “ordinary”
matter left during the black hole era
Another Colored Card Question
The Dark Era begins around which cosmological decade?a) The 10th b) The 101st c) The 40th d) The 80th
One More Colored Card Question
During the Dark Era, typical wavelengths of light are measured ina) kilometersb) metersc) lightyearsd) huge multiples of the size of the
currently visible universe
The Black Hole Era
To understand black holes, we need to explore Einstein’s General Theory of Relativity
The Equivalence Principle
Consequence of Equivalence Principle: Light is affected by gravity
Space-time gets warped near any massive object
Near a black hole the warping of space-time is
extreme
Visual distortions caused by a black hole
Time runs differently near a black hole
Tidal forces stretch and squeeze anything falling into a black hole
The process is called Spaghettification.Watch spaghettification video
Schwarzschild Black Hole
Kerr Black Hole
Most black
holes now are
accreting mass and have jets
Because the star that formed the black hole was rotating and the mass falling in spirals inward, the black hole is rotating: it is a Kerr black hole
The Binary Pulsar
When they finally collide, they will form a black hole.Watch Binary Pulsar and Neutron Star Merger videos
Black holes won’t last
forever
Hawking Radiation
At the end of the Black Hole Era only electrons,
positrons, extremely long wavelength photons and a
few exotic elementary particles remain. The Dark
Era is truly dark
The Dark Era
e+
e-
e-
e+
3010 lightyears
Phase Transitions
Ice pockets forming in a salt water pool
Quantum Mechanical Tunneling
The Universe could tunnel to a new vacuum energy state
The probability of tunneling depends on the wave properties of
the universe
The Heat Death of the Universe
An Alternate End: The Big Crunch
The more likely ending: The Big Rip