Alternate Planets, Suns, Stars, and Solar Systems Thread


Ruhus. A planet of my sci-famtasy setting "Known Stars" that you can find here
Awesome! (replying to @CarnelianClout)
I've been on a roll with alternate solar systems lately, so I came up with an idea. For this one, I allowed myself to move any object in the solar system to wherever I wanted it to be. The only rule that I came up with was that I could not add in any new objects that have not been at the very least hypothesized by mainstream scientists (within reason).

First Planet:

The first planet is Caca and was formed from a large asteroid (Pallas) that got knocked out of the asteroid belt during the formation of the solar system. Subsequent encounters with debris lead the planet becoming fully spherical, with a diameter of around 900km (560) miles. Caca's physical appearance is rather dark, like charcoal. It exists in a small debris belt on the interior orbit of Mercury - dubbed the Vulcanoid belt. Caca and the debris belt have only been discovered thanks to modern developments in astronomy in the 18th and 19th century. Some astronomers also have the theory that Caca is the largest remnant of a previously larger planet (Vulcan).

Second Planet:

Mercury is the second planet with a mass of 0.055 Earths. With a 3:2 orbital resonance, the planet rotates 3 times for every two times it orbits around the sun. Mercury is a bleak world with temperature extremes with no signifiant atmosphere to speak of. Mercury has captured a small asteroidal moon into an unstable orbit. It is not sure how long how this minor moon has been there, but it has the size of 10 kilometers (6 miles). Because of it's likely recent capture - it has the name Juventas, the Roman goddess of youth.

Third Planet:

Mars is the third planet from the sun, with a mass of 0.107 Earths. Due to the planet's small size and proximity to the Sun, it's atmosphere is very thin. It still is thick enough to form clouds. It is a hot, dry, desolate and arid world. Mars is usually seen in the morning or evening skies as a pale reddish-brown dot. The planet has a 25 degree tilt, and a day of 11 hours. Thanks to it's small size and lack of a large moon, it's rotation period is rather fast. Mars has picked up a few asteroidal moons, of Phobos, Deimos, and Dispater. All of which are 20, 15, and 87km in size respectively. The 3 of them orbit fairly close to the planet. Thanks to the gravitational influence of other planets, Mars's axial tilt varies over geological timeframes. Thanks to it's reddish appearance it was named after Mars, the Roman god of war.

Fourth Planet:

Earth and the Moon exist as normal, however in modern times an asteroid flew by the Earth and got caught within Earth's gravitational field, and broke apart, forming a narrow ring over the equator - disrupting the global economic and telecommunication systems as most satellite orbits intersected the newly formed ring, resulting in their destruction.

Fifth Planet:

Venus. Venus is the brightest planet, thanks to it's highly reflective icey surface. The planet is very much a frozen Earth, with some areas of standing water and a teaming ecosystem. Cupid (Ceres) is the largest moon of Venus, which is host to around a dozen smaller asteroid moons. Cupid orbits close into Venus's sphere of influence, resulting in it being the first planetary moon being discovered. Alongside Cupid, there are many other captured asteroids in orbit around Venus - bringing up to a total of 17 moons. Modern astronomers discovered a faint ring system around Venus, being the remnants of a previous moon that was destroyed millions of years ago. Venus is the first planet beyond Earth of which life was discovered by the various probes sent to the planet.

Sixth and 7th Planets:

Jupiter exists as it in our timeline, however, the moon Ganymede (Hercules) was ejected from Jupiter's gravitational influence. It settled into an orbit 90 degrees ahead of Jupiter, being that of a trojan planet with the name Hercules. Thanks to Hercules's small size in comparison to Jupiter, it was assumed to be a minor star. Thanks to modern observation in the 18th and 18th century, Hercules was discovered to be a planet. Hercules's largest moon is 100km in size, named Alcmene. This results in Jupiter having only three major moons (Io, Europa, and Callisto). Hercules has a thin nitrogen atmosphere, enough to form clouds.

8th planet:

Saturn. The 8th planet is characterized by it's large ring system. It is host to the large icey moon of Rhea (which is just comprised of Mimas, Enceladus, Dione, Tethys, and Rhea having merged into one moon during the formation of the Saturnian moon system. Hyperion is also host to large cryovolcanic eruptions that are very visible on the moon's surface, and some say fuel the mass of Saturn's rings. Iapetus and Phoebe also exist, with OTL Hyperion being named Mimas.

During the formation of the Saturninan moon system, the moon Titan was also ejected from Saturn's orbit, and thus we get into the 9th planet.

9th planet:

Existing between the orbit of Saturn and Caelus, the planet Dionysus is roughly twice the mass of our Moon (Titan having come to a larger mass after increased collisions within it's youth). Like Earth and Venus, it is host to a thick atmosphere like in OTL. Dionysus also came into the possession of 11 minor asteroidal moons, all of which share highly eccentric and irregular orbits. Dionysus also has a fairly robust ring system, but thanks to the small size of the planet it was only discovered after the planet Caelus (OTL Neptune).

10th planet:

Caelus (OTL Neptune) had it's orbit swapped with Uranus in the early solar system, resulting in the planet's original moons remaining in place. These moons are quite small, and neither of them are gravitationally rounded. Caelus has a thin but visible ring system. Caelus is a little further out than OTL Uranus.

11th planet:

Neptune (fifth Giant / Planet nine):

In this reality, the 5th giant stays in place in the solar system and it came to have the name Neptune. It is nothing like our own Neptune, being only about 8 times the mass of Earth, with a hydrogen envelope. It is referred to as a "gas dwarf", with it's solid core comprising a much larger portion of the planet in comparison to the other gas and ice giants. In it's formation, Neptune captured the planets Pluto, Eris, Haumea, Makemake, and Varuna into it's orbital sphere to become it's moons under different names.

12th planet:

Somnus. Somnus is the final ice giant in the system and is OTL Uranus, that was kicked into a higher orbit beyond the Kuiper belt. Somnus took with it the remaining dwarf planets to become it's moons, with it's original moons also existing, creating the largest system of moons that are gravitationally rounded. Somnus orbits on its side, with each season many decades.

13th planet:

The largest dwarf planet of them all, Cybele (OTL Triton) avoided capture to become the 13th planet, orbiting far being where the Kuiper Belt sits. Very little is known about it other than that it has a small ring system.

14th planet:

The final planet in the solar system is Sedna, it is the last remaining small planet in the outer solar system as far as astronomers can tell, with the others having been captured by Somnus.