Now that Mars is old hat, this week’s FactSlap column comes with a Venus twist:

• Venus is often called Earth’s twin because it is the closest planet in size to Earth. Scientists estimate the diameter of Venus at about 7,520 miles, making it approximately 400 miles smaller in diameter than Earth.
• Venus travels around the sun in a nearly circular orbit, with its average distance from the sun varying only slightly throughout the orbit. It takes the planet approximately 225 Earth days to travel completely around the sun, compared to Earth’s 365 days.
• With its faster orbit around the sun, Venus overtakes Earth every 584 Earth days, changing from an evening star (visible after sunset) to a morning star (visible before sunrise), and then vice versa.
• Venus is one of only two planets that rotates on its axis clockwise from east to west. The only other planet to do so is Uranus.
• Because Venus rotates very slowly on its axis (taking 243 days to make a complete rotation), a day on Venus is longer than its year.
• Venus is constantly covered by thick clouds of sulfuric acid, through which no visible light can penetrate. For this reason, astronomers have been unable to view the planet’s features through optical telescopes. Most of the knowledge about Venus’ surface has been gained through radar images acquired from U.S. and Soviet space probes.
• When seen from Earth, Venus is brighter than any other planet or any star in the sky. At certain times of the year, it is the first planet or star visible in the western sky at night—and at other times, it is the last planet or star visible in the morning.
• Approximately 65% of Venus’ surface is covered in flat, smooth plains, and the remaining 35% is made up of six mountainous regions. The mountain range Maxwell, which is about seven miles high and 540 miles long, is the highest feature on the planet.
• Venus has far fewer impact craters (created when a planet and an asteroid collide) on its surface than Mercury, Mars, and Earth’s moon, leading geologists to believe that the current surface of the planet is less than one billion years old.
• The atmosphere of Venus is heavier than the atmosphere of any other planet. It is made up primarily of carbon dioxide and exerts an estimated 1,323 pounds per square inch (psi) of pressure on the planet, roughly 90 times more pressure than Earth’s atmosphere