If we fuck up the Earth, we cannot go here.

https://en.wikipedia.org/wiki/Planet_Nine

Characteristics

Orbit

Planet Nine is hypothesized to follow a highly elliptical path around the Sun, with an orbital period of 10,000–20,000 years. The planet would have a semi-major axis of roughly 700 astronomical units (AU), or about 20 times the distance of Neptune from the Sun, though it might come as close as 200 AU (30 billion km), and its inclination estimated as 30 (± 20) degrees.^[1][2][6][A] The high eccentricity of Planet Nine's orbit could take it as far away as 1200 AU at its aphelion.^{[7] [8]}

Size

Planet Nine is estimated to be similar in size and composition to the blue ice giants Uranus and Neptune, pictured here to scale with the gas giants and terrestrial planets.^[9]

 

The planet is estimated to have 10 times the mass^[6][9] and two to four times the diameter of Earth.^[5][10] An infrared survey by the Wide-field Infrared Survey Explorer in 2009 does not exclude such an object as their results allow for a Neptune-sized object beyond 700 AU.^[11] A similar study in 2014 focused on possible higher-mass bodies in the outer Solar System and ruled out Jupiter-class objects out to 26,000 AU.^[12]

Composition

Brown speculates that the planet is most likely an ejected ice giant, similar in composition to Uranus and Neptune; a mixture of rock and ice with a small envelope of gas.^[1][5]