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 is a)free protons and neutrons b)electrons and positrons c)hydrogen and helium d)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 10 th b)The 101 st c)The 40 th d)The 80 th

One More Colored Card Question During the Dark Era, typical wavelengths of light are measured in a)kilometers b)meters c)lightyears d)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- e-e- e+e+

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