Universe Flashcards
How old is the universe
13.7 billion
Weak force
Responsible for radioactive decay, very short range and explains the interactions among subatomic particles (quarks, leptons)
Gravity
Distorts space and time. Very short range but cumulative with mass.
Strong force
Holds the protons and neutrons in the nucleus. Strong force, but acts in a very short range
Electromagnetic force
The force of attraction between particles with a long range that can be shielded. Allows nuclei to attract electrons to form proper neutral atoms
What two factors dictate how strong the electromagnetic attraction will be
The change in the charge of the particles and the distance between them
What elements were present in the early universe?
Hydrogen (76%) helium (24%) tiny amount of lithium
Elements larger than helium come from
Fusion
Describe star formation and the role of gravity
Gaseous clouds of hydrogen and helium coalesce to form more hydrogen and helium until their mass is so great creating a gravitational force strong enough to create a star
Fusion
The joining together of atoms. Only occurs under extreme heat and pressure. It produces elements larger than helium
Low mass stars
Long living stars. Form only hydrogen and helium
Main sequence stars
Form elements up to carbon (element 6)
Massive stars
Form events up to iron (element 26)
Supernova
Form elements larger than iron. A super nova is when a massive star collapses on itself. When the fusion goes away less and less atoms causes more mass in a smaller area increasing the gravitational force causing the star to collapse on itself. Massive implosion
How old is earth
4.5 billion
