Venus has always been regarded as Earth's Sister Planet. After all, it can be the closest planet to us and it is nearly the same size as Earth. Noun. (plural sister planets). (astronomy) a planet that shares similar physical characteristics, such as size, density and mass, with another planet. Venus: Earth's Sister Planet size and mass - and so is sometimes referred to as Earth's sister planet - but Venus has a quite different climate. More Blog - Space articles, diagrams and graphics FAQ - Frequently asked questions about space Posters - Posters about space and the planets. About Us Armagh Planetarium Colin Johnston Michael Burton Solar System Sun Moon Planets Comets and Asteroids Meteors and Meteorites Our Galaxy Milky Way Stars Exoplanets Nebulae Universe Other Galaxies Cosmology Alien Life astronomers Telescopes and Observatories Space Flight Human Exploration Robot Exploration Rockets Earth Satellites Weird and Fun The Future Concept Spacecraft Science Fiction UFOs and Fringe Science Monthly Sky Notes December April August June January November October September July May March February RSS Feed Twitter. As you may have heard, we have something similar here on Earth, and if studying Venus helps us learn how to prevent global warming, that justifies every penny spent on space exploration although the greenhouse gases of Venus probably came from volcanoes rather than powerstations. Astronotes is one of top 60 space blogs! Notify me of follow-up comments by email. The last hope for a planet full of exotic life was literally crushed in the s when the first spacecraft visited Venus. The Transit of Venus will be in another years, but what exactly is it? Add a thank you note? There was a response error processing your form. Why did the southern cotton industry have a hard time recovering after the Civil War? And Keplerb circles a sunlike star that's just 10 percent bigger and 20 percent brighter than the one that hangs in Earth's sky.