The History Channel gives us a two-for-one special in this episode of The Universe, as we take a look at the first two planets orbiting the Sun — Mercury And Venus: The Inner Planets. The episode is broken down into two parts and takes a look at the more interesting planet Venus, Earth’s “sister” planet, first and is followed by a slightly rushed look at Mercury. As both planets are solid, unlike the gaseous outer planets, the episode and the scientists interviewed are able to talk about the similarities and differences of these inner planets to Earth, and how by studying these two planets has helped to answer questions about our own planet.
Venus, named for the Roman goddess of beauty, is often referred to as Earth’s “sister” planet, due to it similar size and mass, and it was once believed that Venus was covered with oceans before space exploration gave a much more harsh and truthful image of the planet. Venus is a violent world, with temperatures exceeding 900 degrees, billions of lightening bolts arching across the sky, erupting volcanoes and lava flows stretching for miles, and clouds made of sulfuric acid. It is this cloud make up which creates a greenhouse effect on the planet and thus makes the temperature so hot. Interestingly, it was scientists studying Venus and its greenhouse gases that gave way to the discovery of the greenhouse effects currently at work here on Earth.
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