I wrote this sci-fi story with the goal of having themes and concepts be grounded in hard science. This meant no faster than light travel or communication, no transporters, no artificial gravity on each deck of a non-rotating ship, no cloaking devices, no characters with magical powers, no cryosleep, etc. As I wrote the story, I investigated the plausability of each event.

Unfortunately for science fiction, the interstellar medium and small particles in space impose a strict speed limit, even with magically unlimited fuel and resources. A maximum speed of 10% of the speed of light would cause severe erosion and damage to a ship within a few months without energy-intensive shielding. Speeds above 20% of the speed of light would cause structural damage to ship and crew within weeks, even with shielding. Speeds above 90% of the speed of light would cause every atom of hydrogen struck by the ship to have the energy of an X-ray or even higher energy particle, irradiating ship and crew almost instantly. Interstellar travel is far more difficult than science fiction depicts!

In order to depict an alien species traveling 23 light years to Earth from Oma (Gliese 667 Star C planet c) and Earth, I used the Relativistic Rocket Calculator. I estimate that even a species with a mastery of energy and physics could not keep a ship and crew alive for long traveling more than 20% of the speed of light. According to the calculator, accelerating up to almost 20% of light speed for 1% of the trip, coasting for 98% of the trip, (which still requires a lot of energy to remain at that speed,) and decelerating the last 1%, gets the Omanji 23 light years to Earth in about 120 years. The atoms in the interstellar medium erodes spacecraft and shields at that speed. Hitting a rare particle the size of a grain of sand or larger produces a large explosion which could easily destroy a spacecraft.

Enter the following into your favorite AI to reveal the gory details! Even 20% of light speed requires near God-like technology. The AI may take some time answering this.

Be an astrophysicist, specializing in the challenges of traveling in space at a significant percentage of the speed of light. Descibe the effects on a spacecraft of traveling at 20% of the speed of light for 120 ship years, while passing through the interstellar medium, encountering particles the size of smoke, impacting particles the size of a grain of sand, and hitting particles the size of a pea. Ignore the small effects of the cosmic background radiation. Ignore calculating time dilation.

The planet Oma is modeled after Gliese 667, Star C, planet c. It is almost 4 Earth masses and likely has a lot of internal heat, which leads to tidal heating and severe volcanic activity. It orbits close to its dim red star and may be tidally locked. I imagine it as a mostly oceanic world with a dense atmosphere, which retains heat and is on the inner side of the habitable zone. I imagine it to be slightly hotter than 2026 estimates. If it had two continents at the poles, non-technological beings on either continent may evolve independently due to ocean currents and winds keeping them apart.