In a solar system light years from Earth are two exoplanets that don't orbit around their sun like our planet does, but orbits each other while they orbit their sun. Our moon orbits us because it is much smaller, yet these two planets are exactly the same size to each other, therefore they orbit a center of mass that sits right in the middle between them. They are tidally locked so they constantly face each other, and if you were to stand on one of these planets, look up you will see the other permanent and unchanged in the sky.
Their sun is just like our sun, same size and temperature and they sit in the habitable zone, which is the same distance we are to our sun, not too hot and not too cold. The planets are the same size to Earth, no bigger, no smaller, which makes their gravity just like ours. If we were to stand on either planet, we would still weigh just the same as we do here on Earth. They have just the same make up of elements that you'd find on Earth, such as oxygen and water. Just like Earth they both have diverse regions, frigid poles just like our north and south poles, tropical zones around their equators, rainforests, deserts, and all other land features you would find on Earth.
 
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