i have no idea what i'm doing
correct me if i got a thing wrong
also here's a redshift thingy plug. yeah it's doppler redshift and not cosmological redshift sure but whatever it might be a good thing to use in order to help visualize redshifts and blueshifts
Red universes[]
A universe is red if it is expanding. The scale factor as a function of time in a considered time period of a red universe is some monotonically increasing function. Red universes are called "red" since a good chunk of faraway objects will appear cosmologically redshifted to an observer in the universe. Open universes and flat universes with lots of dark energy generally live most of their lives as red universes before dying as a farred universe in a Big Rest In Peace. Closed universes that are hyperspherical start off red but evolve into green and then blue universes before dying as a violet universe in a Big Crunch scenario. Introduction of dark energy to a blue universe can make it a red universe. Universes can become red when they are filled with dark energy. A multiverse is called a red multiverse if is composed of most dominantly red universes. "Younger" multiverses are often red multiverses.
Our universe is currently a red universe.
Blue universes[]
A universe is blue if it is contracting. The scale factor as a function of time in a considered time period of a blue universe is some monotonically decreasing function. Blue universes are called "blue" since a good chunk of faraway objects will appear cosmologically blueshifted to an observer in the universe. Closed universes that will end their lives in a Big Crunch will evolve into a blue universe before they keel over and die as a violet universe. A multiverse is called a blue multiverse if is composed of most dominantly blue universes. "Older" multiverses are often blue (or green) multiverses. Multiverses that are comprised of most dominantly red and blue universes are known as purple multiverses and these can be seen as a transitional stage of multiverse from red to blue. Purple multiverses that are redder can be considered magenta multiverses while purple multiverses that are bluer can be considered indigo multiverses. The "colour" of a multiverse of finite universe count can be found from the ratio of red universe to blue universes while the "colour" of some homogeneous multiverse of infinite universe count can be found from the ratio of reds to blues in some arbitrarily large neighbourhood of some universe.
Our universe probably won't become a blue universe.
Green universes[]
A universe is green if it is not expanding or contracting. The scale factor of a green universe is constant. To an observer within the universe, faraway objects will not be cosmologically redshifted or blueshifted. Some green universes can possess a structure of spacetime that perfectly conforms to special or Galilean relativity (Plug: spacetime globes) without any expansion or contraction to make the math more complicated than it already is. Expanding flat universes without dark energy get greener and greener with time as their expansion asymptotically approaches zero with time.
Closed universes can very briefly be a green universe when the expansion of the universe slows until it stops expanding before the universe starts contracting due to forces such as gravity and becomes a blue universe.
A multiverse is called a green multiverse if is composed of most dominantly green universes and/or evolved dark energyless universes so absurdly close to being green that it probably shouldn't be illegal to call them green.
Multiverses that are comprised of most dominantly red and green universes are known as orange, yellow, or chartreuse multiverses and these can be seen as transitional stages of multiverse from red to green. Orange multiverses have a much higher red universe content than green universe, yellow multiverses have an equal or about equal amount of red as green, and chartreuse multiverses have more green than red.
Multiverses with a high content of red, green, and blue universes are known as white multiverses. Younger "red-toned" white multiverses (or red or purple multiverses with a significant green universe content) are known as pink multiverses.
Orange universes[]
An orange universe fluctuates between expanding and contraction relatively rapidly but things in the universe in general have a net increase in distance from each other given an arbitrarily large period of the universe's time as an orange universe. Simply, an orange universe "pulsates" but expands more than it contracts. In a sense a universe is "globally red" during the time it is an orange universe. Orange universes often spend more time as red universes than blue universes during their "periods".
Yellow universes[]
A yellow universe fluctuates between expanding and contraction relatively rapidly but things in the universe in general have no net increase or decrease in distance from each other given an arbitrarily large period of the universe's time as an yellow universe. An yellow universe pretty much just "pulsates" but their expansions and contracts cancel each other out. In a sense a universe is "globally green" during the time it is an yellow universe. Yellow universes often spend equally as much time as a red universes as a blue universes during their "periods". Plenty of types of cyclic or oscillating universes can be considered yellow universes.
Cyan universes[]
A cyan universe fluctuates between expanding and contraction relatively rapidly but things in the universe in general have a net decrease in distance from each other given an arbitrarily large period of the universe's time as a cyan universe. Essentially, an cyan universe "pulsates" but contracts more than it expands. In a sense a universe is "globally blue" during the time it is a cyan universe. Cyan universes often spend more time as blue universes than red universes during their "periods".
Violet universes[]
A universe becomes a violet universe when its scale factor is tending to zero in a Big Crunch scenario. A violet universe can form when a universe's spacetime is very dense with matter and when gravity from said matter greatly overpowers any expansion that would occur to the universe. Objects in a violet universe can appear to be extremely blueshifted. The penultimate state of a closed universe before the universe essentially becomes an infinitely hot, infinitely dense singularity not all that dissimilar to a Big Bang state of a universe.
Our universe is probably not going to ever become a violet universe.
Farred universes[]
A universe becomes a farred universe when its scale factor is tending to infinity in a Big Rip scenario. Farred universes have an extremely rapid expansion rate that can become googologically high in an instant and tends to infinity. Objects in a farred universe can appear to be extremely redshifted. A farred universe can very quickly form when a universe's spacetime is filled with phantom energy. The penultimate state of an open universe before everything inside the universe is completely destroyed and spacetime is completely ripped apart.