Venus, the second planet from the Sun is named after the Roman goddess of love and beauty. It is the second brightest object in the night sky after the moon. Earth and Venus are pretty similar in size and mass. Here a great depiction of the relative sizes of the rocky planets in our solar system (plus Pluto):
Venus is Hellish
From Earth, Venus looks beautiful, and until the 1960’s it was speculated that Venus was a tropical paradise. That notion couldn’t be further from the truth as the surface of Venus is hellish. The temperature at the surface averages about 900 degrees, which is hot enough to melt many metals including lead and tin, and if you were to walk on the surface, you’d wade through molten metal.
It rains sulfuric acid and the atmospheric pressure is about 92x of what it is on Earth’s surface. Thus, merely standing on the surface of Venus would result in you being crushed just like if you were thousands of feet below the surface in an ocean on Earth.
Greenhouse Effect
Billions of years ago Venus’s atmosphere might have similar to Earth’s, and Venus might have had water oceans. Why is Venus so hellish now? A runaway “greenhouse effect.”
Carbon dioxide acts as a one-way street for sunlight. Light can readily enter through the carbon dioxide in Venus’s atmosphere because the gas is transparent. But once the light bounces off the ground, it turns into heat or infrared radiation, which cannot easily escape the atmosphere. The radiation becomes trapped, in a process similar to the way a greenhouse captures sunlight during winter or the way cars heat up in the summer sun. This process happens on the Earth, but it is vastly accelerated on Venus because it is much closer to the sun, and a runaway greenhouse effect was the result.
Source: The Future of Humanity by Michio Kaku
Other Interesting Venus Facts
- Venus has no moon(s).
- Venus rotates on its axis in the opposite direction than the Sun, Earth and the rest of the planets except for Uranus. Viewed from above their north poles, Venus and Uranus rotate clockwise while the sun and the other planets rotate counter-clockwise.
- It takes Venus 243 Earth days to rotate once on its axis (as compared to the 24 hours it takes Earth).
- It takes Venus 225 Earth days to orbit the Sun (as compared to the 365 days it takes Earth). Thus, a year on Venus is 19 Earth days less than a Venusian day (sidereal day).
- Venus is the closest planet to Earth at about 25 million miles (when Venus, Earth and the Sun are in alignment).
Is this the new and gentler Physics Friday? Where’s my String Theory?!