It's a planet somewhat similar to Earth. It's a little bit smaller, but the land mass on Mars is about the same as the land mass on Earth, you know, if you don't take the oceans into account.
火星是个类似地球的星球。稍微小一点儿， 火星的组成和地球很相似 火星的组成和地球很相似 如果不算上海洋的话。（火星没有海洋）