Ed White, the first American to perform a space walk. Image credit: NASA
You've learned so much about planets, moons, stars, galaxies, and all sorts of other astronomical objects, but do you have any idea about what space is really like? Outer space in general is very very cold. It's temperature is roughly 2.7 Kelvin, or -455 degrees F. Space is almost a perfect vacuum. A perfect vacuum is defined as an area of space with zero gas molecules. Outer space contains about 5 Hydrogen atoms per cubic meter. For comparison, on Earth there is about 10^25 gas molecules per cubic meter (that's a 1 with 25 zeros after it!). Space may be empty of molecules, but it's filled with light, most of which our eyes can't perceive. In the solar system, the sun emits all different types of light, from X-rays to microwaves. Earth's atmosphere blocks a majority of this light, but in outerspace there is nothing to block this light. These are some of the many reasons why astronauts must wear space suits. With essentially no air to breathe, freezing temperatures, and deadly radiation, an astronaut would survive about 30 seconds if they took off their space suit. NASA has spent many years building spacecrafts and spacesuits that can withstand the harsh conditions in Space. They have done a pretty good job so far, but space is also very unpredictable. You never know what's going to happen out there!
