Are there planets similar to the Earth?

Three planets, Mercury, Venus, and Mars, resemble the Earth to some extent. They are made up of rocks, and have a similar structure consisting of the crust, mantle, and core. Moreover, they are relatively close to the sun, and hence are not ice-cold; except for Venus, all of them have seasons. Nevertheless, these planets are very different from the Earth. Mercury, covered with craters, and Mars, Sometimes called the 'little brother of the Earth', have a very thin atmosphere; the brightly shining Venus has an atmosphere much denser than that of the Earth. Even Pluto, which is far away from the sun and consists mainly of rocks, is quite different form the Earth.