A primitive ocean on Mars held more water than Earth’s Arctic Ocean, and covered a greater portion of the planet’s surface than the Atlantic Ocean does on Earth, according to new results published today. http://www.eso.org/public/news/eso1509/
Although Venus is only the planet second nearest the sun, its dense, toxic atmosphere traps heat in a runaway version of the greenhouse effect that warms up the Earth. As a result, temperatures on Venus reach 870 degrees F (465 degrees C), more than hot enough to melt lead.
In 1989, Voyager 2 made our first close encounter with the stunning blue planet Neptune. Its surprisingly turbulent, storm-laden atmosphere, this far from the sun, was clearly being driven by heat from deep within the planet