Chapter 21 - Section 5 - The Expanding Universe Flashcards
What is the big bang theory?
theory that the universe formed in an instant, billions of years ago, in an enormous explosion.
How did the solar system form?
About five billion years ago, a giant cloud of gas and dust collapsed to form our solar system.
What do astronomers predict about the future of the universe?
the universe will likely expand forever
big bang
The initial explosion that resulted in the formation and expansion of the universe.
Hubble’s law
The observation that the farther away a galaxy is, the faster it is moving away.
cosmic background radiation
The electromagnetic radiation left over from the big bang.
solar nebula
A large cloud of gas and dust, such as the one that formed our solar system.
planetesimal
One of the small asteroid-like bodies that formed the building blocks of the planets.
dark matter
Matter that does not give off electromagnetic radiation but is quite abundant in the universe.
dark energy
A mysterious force that appears to be causing the expansion of the universe to accelerate.
What force caused the solar system to form?
gravity
How old is the solar system?
5 billion years old
When did the big bang occur?
billions of years ago
