Ch. 30. 4 - The Big Bang Theory
Why is the cosmic background radiation uneven in some places?
Matter was not spread out evenly in the early universe.
cosmic background radiation
radiation uniformly detected from every direction in space; considered a remnant of the big bang
cosmology
the study of the origin, properties, processes, and evolution of the universe
big bang theory
the theory that all matter and energy in the universe was compressed into an extremely small volume that 13 to 15 billion years ago exploded and began expanding in all directions
How do scientists detect dark matter?
They detect its gravity.
How does the red shift of distant galaxies support the big bang theory?
According to the big bang theory, the universe is expanding. The expansion causes the galaxies to move away from each other. Red shift shows that the galaxies are moving away from each other.
What did Hubble discover in the 1920s?
All the spectra of distant galaxies are redshifted.
How is dark matter different from regular matter? How are they similar?
Both dark matter and regular matter produce gravity. Unlike regular matter, dark matter does not emit or reflect light.
How does the big bang theory explain the existence of cosmic background radiation?
Cosmic background radiation is a constant, low level of energy from everywhere in the universe. The big bang theory can explain cosmic background radiation. According to the big bang theory, cosmic background radiation formed just after the big bang.
How is cosmology different from astronomy?
Cosmology is the study of the origin, evolution, and future of the universe as a whole. Astronomy is the study of the objects in the universe, such as stars and planets.
Describe Edwin Hubble's observations, and explain how they show that the universe is expanding.
Hubble observed that the light from all distant galaxies is red-shifted. Red shift happens when a light source is moving away from an observer. Since all the galaxies in the universe are red-shifted, they must all be moving away from Earth. Therefore, the universe must be expanding.
If an object's spectrum is blue-shifted, what can you conclude about the object's motion?
It is moving toward Earth.
Describe the big bang theory for the origin of the universe.
The big bang theory states that everything in the universe was once compressed into a single point. About 14 billion years ago, the matter and energy in the universe began to expand suddenly. The expansion was called the big bang. The universe is still expanding today.
Why are distant galaxies moving away from our galaxy more quickly than nearby galaxies are?
There is more space between our galaxy and distant galaxies, and the whole universe is expanding.