Galaxy
A huge collection of billions of stars, gas, and dust held together by gravity
The big bang theory
The most widely accepted explanation for the origin of the universe. Theory states that all the matter and energy in the universe was compressed into a single extremely hot, dense point that was smaller than an atom which expanded 13.8 billion years ago and has been expanding ever since
Cosmic microwave background
Left over thermal radiation from when the first light that could travel freely when the universe was 380,000 years old
CMB strength
matches predicted characteristics of the hot, dense early universe that expanded and cooled as described by the bbt
weakness CMB
Consistency shows variations of 1 in 100,000. This indicates that the universes most distant parts were once the same temperature, suggesting the heat from the big bang was distributed evenly in all directions. However due to the universes age and the speed of light this should be physically impossible
Observable universe
The part of the universe we can detect because its light has had time to reach us
how gravity forms galaxies
Gravity binds stars, along with gas and dust into large, gravitationally bound structures.
How gravity forms stars
Its pull causes vast clouds of gas and dust in space to condense and collapse, eventually forming dense enough regions to ignite nuclear fusion, which creates stars.
