AST 112 - Chapter 29 - Week 7

According to Hubble’s Law, what relationship exists between the distance of galaxies and their recessional velocities?

The farther away a galaxy is, the faster it is moving away

How is the age of the Universe estimated?

By using the value of Hubble’s constant in the formula T(o) = 1 / H(o)

How old is the Universe, roughly?

14 billion years

What are two things that are almost as old as the Universe?

The ratio of uranium isotopes in very old stars, and stars in the oldest globular clusters

What unexpected discovery about the universe’s expansion was made through observations of Type 1a Supernovae?

The expansion of the universe is accelerating

What force is responsible for causing the recessional velocities of galaxies to potentially slow down?

Gravitational force

How do astronomers estimate the distance of galaxies using Type 1a Supernovae?

By understanding their inherent brightness and observing their apparent brightness

What does the expansion of the Universe refer to?

Galaxies moving away from each other

What allows cosmologists to assert that the Universe was hotter and denser in the past?

The observation that galaxies are moving away from one another now

How does the popular misconception of the Big Bang differ from the view shared in the lecture video?

The Big Bang incorrectly assumes that the Universe started at a single point and expanded into something empty

If the Universe was very hot at the beginning, what do we expect based on that information?

That it was full of radiation at the beginning

What is true about the expanding Universe?

It is infinite, and doesn’t have discrete edges

What was the significant discovery made by Robert Wilson and Arneo Penzias in 1964?

The cosmic microwave background radiation

What did the Cosmic Microwave Background Radiation help to confirm about the Universe?

That the Universe began with the Big Bang

What did the Steady State Model propose about the Universe?

That the Universe has always existed and expands with constant density

According to the Big Bang model, what was a key characteristic of the early Universe?

It was very hot and dense

What ultimately happened as a result of the discovery of the Cosmic Microwave Background (CMB)?

It favored the Big Bang model over the Steady State Model