A Year in a Day
The planet Venus has an internal structure similar to that of the Earth’s; a molten core that erupted volcanically for millions of years and then solidified to form a mantle and crust. Though Venus and the Earth may be similar in size and density, their movement through the solar system couldn’t be more different.
Venus is the slowest planet, rotating on its axis once every 243 “earth” days. In contrast to the Earth, Venus orbits the sun faster than it rotates on its axis, and it spins on its axis in a clockwise direction. This means that if you were standing on the surface of Venus, a day would be longer than a year and the sun would appear to rise in the west and set in the east. Scientists theorize that when the solar system was forming 4.5 billion years ago, Venus might have been bombarded by comets or even a small planet, causing it to either reverse its rotation or to flip upside-down.
Without oceans of water to cool the outer crust and cause tectonic plates to form, the surface of Venus radiates heat into the atmosphere. The heat is contained by a layer of gas consisting of 95% carbon dioxide and 3% nitrogen, topped with clouds of sulfuric acid, causing Venus to be the hottest planet in the solar system even though it’s further away from the sun than Mercury.
A small degree of axial tilt means there aren’t any seasonal changes in temperature on Venus, which hover around 462 C (863 F) whether it’s daytime or night.
The appearance of Venus in the morning and evening sky inspired the Romans to name the planet after their goddess of love and beauty
Earth’s Unfriendly Neighbor
Though Venus is only 38 million kilometers from earth, the planet’s heavy atmosphere and sulfuric acid cloud cover make it a difficult place to explore.
From 1961-1984, the Soviet Union led the exploration of Venus with the Venera program. Besides constructing and navigating a spacecraft that could fly within Venus’ atmosphere, and being the first to send a lander to the surface, the Soviets collected temperature and atmospheric data and produced the first color images of Venus.
NASA’s Mariner 2 was launched in 1962. The spacecraft not only explored Venus’ atmosphere and magnetic field, it took readings of the solar winds and the levels of space dust present in interplanetary space.
The ESA’s Venus Express completed a long-term study of Venus’ atmosphere and weather patterns from 2005 to 2013. Concurrently, the Akatsuki was launched by Japan in 2010 and arrived at Venus in December of 2015. The orbiter is furthering the exploration of the atmosphere of Venus with spectrometers that take measurements of the planet using different wavelengths of light.