Venus is a hot, hot planet, but a series of experiments done by the European Space Agency’s Venus Express, meant to be its swan song, has thrown up three surprises.
One: at minus 250 degrees Fahrenheit, the Venusian atmosphere, on the whole, is far colder than anywhere on Earth.
Two: the polar regions are not as dense as was expected.
Three: they have strong “atmospheric waves,” which are like waves on the ocean or ripples in a pond. Only, they travel vertically; not horizontally, from lower to higher altitudes, becoming stronger as they rise. Another kind of wave, known as “planetary waves,” are also present. The atmospheric equivalent of tsunamis, they occur due to a planet’s rotation.
Venus Express arrived at Venus in 2006. It spent eight years, studying it from orbit, “vastly outliving the mission’s planned duration of 500 days” before running out of gas. Before it bid farewell, it engaged in an aerobraking campaign—a maneuver in which a spacecraft flies through a body’s atmosphere to reduce its speed.