Exam 17: The Beginning of Time

The Big Bang theory seems to explain how elements were formed during the first few minutes after the Big Bang. Which hypothetical observation below (these are not real observations) would call our current theory into question?

Why can't current theories describe what happened during the Planck era?

Why is the night sky is dark?

Which of the following histories are in the correct order of occurrence?

Why might inflation have occurred at the end of the GUT era?

The observed composition of ordinary matter in the universe-roughly 75 percent hydrogen and 25 percent helium-closely matches theoretical predictions based on the Big Bang model.

Which event in the history of the universe happened last?

Refer to this scenario for the following questions: A multi-dimensional being reaches down to Earth and pulls you out of the universe. You are then thrown back into the universe at a place and time of the being's choosing, and you are permitted to leave only after you have identified your surroundings. This process is repeated several times. Through a scientifically unexplainable miracle, you are able to survive in every one of the places that you find yourself. In each scenario below, identify your surroundings (and potentially your cosmic era) from among the choices given. -A moment before, you were enveloped in a bright plasma. You could not see very far as free electrons zipped around your head, scattering photons. But now, the universe has suddenly become transparent and you can see clearly. There seem to be no planets or stars, only a gas filled with mostly neutral hydrogen atoms. Where are you?

Laboratory experiments conducted with particle accelerators confirm predictions made by the theory that unifies ________.

Why is the nucleosynthesis era so important in determining the chemical composition of the universe?

Evidence for Inflation: What is the observational evidence the universe underwent a brief but very rapid period of inflation at the end of the GUT era, early in the history of the Universe. Does any of this evidence count as direct observational evidence? Does the validity of the Big Bang depend on inflation being correct?

Observations of the cosmic background radiation from the COBE satellite revealed tiny variations in its temperature by about 1 part in 100,000.

Which of the following statements correctly summarizes the events in the early universe according to the Big Bang theory?

In principle, if we could see all the way to the cosmological horizon we could see the Big Bang taking place. However, our view is blocked for times prior to about 380,000 years after the Big Bang. Why?

Which of the following claims cannot be proved or disproved by science?

The Planck era refers to the time period

What is the significance of the Planck time?

What is Olbers' paradox, and what is its resolution?

Recent measurements of temperature fluctuations in the cosmic microwave background radiation indicate that 72 percent of the mass-energy in the universe must be in the form of dark energy.

Briefly explain how Hubble's discovery of a relationship between galactic distance and redshift led to the idea of the Big Bang.