When you feel as though you are falling in a dream, it actually comes from the brain falling asleep too quickly, and it basically assumes that it is dying. There is a part of your brain that is essentially responsible for waking you up. Sometimes it wakes up a bit faster, or it falls asleep a little faster than the rest of your dream. In addition, the common dream of being paralyzed is also related to this body-brain disconnect.
20. Sound Doesn’t (Really) Travel in Space
There are simply no molecules in space for sound to vibrate between. Technically there are molecules - but they're spread so far apart that a sound's vibration is unable to reach them. The result is a really low frequency that's barely discernible. So, basically, in space, no one can hear you scream.