Cosmic Expanse is a Space Addon for cosmic horizons which adds a new solar system with 7 (for now) celestrial bodies with 5 planets and 2 moons.

NOTE: the planet nyx and the moon ryue are basically planet forms of nether biomes so you can still get basalt and blackstone and other nether themed stuff.

Requirements; This mod requires cosmic horizons to work, 

Planets 

This Mod adds 6 planets

1 Nyx: A Semi volcanic planet that is hostile to most life, there are no trees but instead it has fungi and patches of nylium and fungi trees.

2 Hyceania: A planet that is located where mars would be in this solar system, it also is too cold for most plant life so it alo has mushroom trees, There are plenty of boulders and the water is a weird whiteish color.

3 Borealis: A Cold planet that is well cold it has snow for the surface and the water is mostly frozem.

4 Aurelia: A desert planet that if im correct holds emeralds so this is the planet to go if you want emeralds it is an arid planet that hosts no water so its like a super sahara. 

5 Yoru: This planet is the only gas giant (For now) it is a blue jupiter type planet that has 2 moons orbiting it. However it is a "Super Puffy" planet so to say so it does not have much density or a great gravitational pull on its moons. its surface is just 4-5 layers of powdered snow.

Eretos: Named after Erebus the greek deity of darkness and Ploutos, the greek deity of wealth and abundence. So ERE(erebus) and Tos(Ploutos). Eretos is Dark and is rich in diamonds (the original texture was much darker but looked too weird so cobbled deepslate and deepslate are the best for surface.

Moons

1 Ryue: This moon is the planet equivalent of a basalt deltas without the mobs, it is uninhabitable and mostly barren and it orbits Yoru.

2 Osuae: Osuae is the most earth like celestrial body out of them all, it hosts mobs like pigs and cows and also has melons and has grass so you could live off the land so to say on this moon.

Extra Additions

There are also other additons too in this mod that are added.

1 This mod adds 2 systems from the base cosmic horizons mod into this mod so vs travel is possible but it would take a while. ;) 

(Note: you may want to use vs hyperdrives with this mod as it helps you to get to specific planet coardinates and is just a great mod shout out to the mod creator for making that mod.)

Lore and questions

1: The reason why osuae does not have giant tidal waves is because that the planet it orbits is a low mass puffy planet so it exerts a less intense gravitational pull than what it should normally do so no giant tsunamis thankfully.

2: The reason why the planets and moons all have a breathable atmosphere is that the onyx system was born in a oxygen and nitrogenus rich nebula which caused the solar system to be very breathable even on gas giants.

3: The reason for hyceanias white water is due to the spores from the mushrooms, although not lethal it can still lead to water dilution, but other than that the water is safe to drink..... Probably.

4: The reason why eretos is rich in diamonds is because early in the planets history it was born out of mmostly carbon and a hot mantle and core and eretos was also very dense and heavy before it lost most of its material, because it was so pressurised and hot in eretos' early history it caused diamonds to be born out of the pressure and heat which is why diamonds are so abundent. In short heat and pressure from eretos' core caused the carbon to become diamonds.

5: The reason why eretos is less volitile and heavier than what they should be along with the rest of the planets and moons is because long ago much like in our solar system, there were more protoplanets and protomoons but also like in our solar system, Eretos collided with a moon called Caliphys which was a low mass, europa sized moon which caused alot of material to be ejected causing the lower gravity experienced in game. This lore piece is similar to how scientists believe the moon was formed because of a collison with a protoplanet called theia which caused early earth to gain a moon, maybe two, idk.

Stars

The Star added in this mod is Onyx a purple dwarf star, Unlike red dwarf stars which burn for trillions of years but are volitile, purple dwarf stars burn for 10 decillion years. The reason why is because the star burns with low burning fuel the lowest burning of the lowest which allows the start to still emit enough heat and energy but also ends up leading to less volitile flaring. 

Planned Features

The planned features for this mod are a few new planets maybe titan for saturn.

NOTE: this mod may crash unexpectedly so feel completely free to send errors in the comments.