Science Flashcards
How long go did the big bang occur
13.8 billion years ago
What occurred in the Hadron epoch?
The universe cooled sufficiently to allow quarks to bind together into hadrons
What are quarks
an elementary particle and fundamental constituent of matter; the combine to form hadrons, the most stable of which are protons and neutrons
What occured in the nucleosynthesis stage?
Between 3 and 20 minutes after the big band, the temperature of the universe cooled down enough to allow atomic nuclei to form via nuclear fusion
When did recombination occur?
about 377,000 years after the big bang
What happened in the recombination era?
Hydrogen and helium atoms form
What happened in reionization?
The first stars and quasars form due to gravitational collapse
When did the first stars form
around 100-200 million years after the big bang
the milky way began as
one or several overdensities in the mass distribution shortly after the big bang
the milky way has grown through
galaxy mergers and accretion of gas directly from the galactic halo
It is believed that earth consolidated
4.54 billion years go
Earth was formed from
gravity consolidating swirling gas and dust
Much of early earth was magma due to
frequent collisions, including with Theia
The earth’s cooling caused
formation of solid crust and allowed liquid water
When did life begin on earth
at least 3.7 billion years ago
