Week 1 - Lesson 1.1 Formation of the Universe - The Big Bang Theory Flashcards
If the universe is expanding, the next logical thought is that in the past it had to have been smaller. A point even.
The time when the universe began is the explosion known as the
Big bang
the most widely accepted cosmological explanation of how the universe formed. If we start
at the present and go back into the past, the universe is contracting — getting smaller and smaller. What is the end
result of a contracting universe?
Big bang theory
According to this theory, the universe began about 13.7 billion years ago. Everything that is now in the
universe was squeezed into a very small volume. Imagine all of the known universe in a single, hot, chaotic mass.
An enormous explosion — a big bang — caused the universe to start expanding rapidly. All the matter and energy
in the universe, and even space itself, came out of this explosion.
Big bang theory
What came before the Big Bang?
There is no way for scientists to know since there is no remaining evidence.
In the first few moments after the Big Bang, the universe was unimaginably hot and dense. As the universe expanded,
it became less dense and began to cool. After only a few seconds, ____,_____and _____could form.
protons, neutrons, and electrons
The matter in the early universe was not smoothly distributed across space. Dense clumps of matter held close
together by gravity were spread around. Eventually, these clumps formed
countless trillions of stars, billions of
galaxies, and other structures that now form most of the visible mass of the universe.
If you look at an image of galaxies at the far edge of what we can see, you are looking at great distances. But you
are also looking across a different type of distance. What do those far away galaxies represent?
Because it takes so
long for light from so far away to reach us, you are also looking back in time (Figure 1.2).
After the origin of the Big Bang hypothesis, many astronomers still thought the universe was _______. Nearly all came
around when an important line of evidence for the Big Bang was discovered in 1964. In a _____ universe, the space
between objects should have no heat at all; the temperature should measure 0 K (Kelvin is an absolute temperature
scale). But two researchers at Bell Laboratories used a microwave receiver to learn that the background radiation in
the universe is not 0 K, but 3 K (Figure 1.3). This tiny amount of heat is left over from the Big Bang. Since nearly
all astronomers now accept the Big Bang hypothesis
Static
________, a scientist at Lawrence Berkeley National Lab, shared the 2006 Nobel Prize in Physics for his work
on the origin of the universe. Using background radiation detected by the Cosmic Background Explorer Satellite
(COBE), he was able to make a picture of the universe when it was 12 hours old.
George Smoot
states that the universe began as a point and expanded outward.
Big bang theory
No one can know what came before the Big Bang because there is no remaining evidence.
-read-
The tiny bit of ______in the universe is energy remaining from the Big Bang
.background radiation
