Venus is the second planet from the Sun and Earth's closest neighbor in the solar system. Venus appears as the brightest object in our night sky after the Moon, which is why ancient civilizations named it after their goddess of beauty. You can often spot Venus just after sunset or before sunrise, shining so brilliantly that people sometimes mistake it for an airplane.

Despite its beautiful appearance from Earth, Venus is actually one of the most hostile places in the solar system. Its thick atmosphere traps heat so effectively that the surface temperature reaches about 900 degrees Fahrenheit, hot enough to melt lead. The atmospheric pressure on Venus is crushing, about 90 times stronger than Earth's, equivalent to being about 3,000 feet underwater. Clouds of sulfuric acid swirl through its sky, and the planet rotates so slowly that a single day on Venus lasts longer than a Venusian year.

Scientists once thought Venus might harbor life because it's similar in size to Earth and closer to the Sun. Space probes revealed the truth in the 1960s and 1970s: Venus shows us what happens when a planet's atmosphere runs away with greenhouse gases. Some probes that landed there survived only minutes before the extreme conditions destroyed them.