Big bang theory Flashcards
what does the big bang theory explain?
it explains that the universe was created 13.8 billion years ago
- begins with singularity (single point of pure energy)
- began massive and rapid expansion- sent space,time, matter in all directions
what are the evidences of the big bang
- cosmic microwave background- leftover radiation from the early universe
- supports that the early universe was hot and dense - hubble’s law- galaxies are moving away from each other
3.abundance of light elements- hydrogen, helium, lithium match predictions
What happened during the Inflationary Epoch?
The universe expanded rapidly, growing from the size of an atomic nucleus to that of a grapefruit in a tiny fraction of a second
What is the Electroweak Era?
It is the period when the universe was still undergoing super-fast inflation
What characterized the Particle Era?
A: The universe was still a boiling hot soup of electrons, quarks, and other particles.
What occurred during the Hadron Epoch?
The rapidly cooling universe allowed quarks to clump together into protons and neutrons.
What defined the Radiation Era?
High-energy waves dominated, including X-rays, ultraviolet rays, and light waves.
What happened during the Nucleosynthesis Era?
Protons and neutrons combined to form the nuclei of hydrogen, helium, and lithium.
What was the Era of Atoms?
Electrons combined with protons and neutrons to form neutral atoms, allowing light to shine freely for the first time.
When did matter begin to dominate over radiation?
Around 380,000 years after the Big Bang, matter began to form small neutral atoms.
How did stars and galaxies form?
Irregular gas clouds collapsed under gravity, gaining enough mass to ignite and produce light, forming systems of stars.
What is the Era of Galaxies?
Gravity acted on hydrogen and helium, causing gas clouds to form into galaxies and clusters of galaxies
What happens when stars die?
First-generation stars exploded, releasing heavy elements into space, which later formed new stars and planets.
What is the CMB, and why is it important?
The CMB is faint radiation left from the Big Bang, providing a “snapshot” of the early universe. It confirms the universe was once hot and dense.
How do we know the universe is expanding?
Light from distant galaxies is redshifted, meaning they are moving away from us. This observation supports Hubble’s Law.
