Water content in air naturally cools it, as water requires some 4000 times more energy to warm when compared same mass of air. (wattsupwiththat.com)
But on moon one using same mass of rocket fuel as payload - 0ne ton payload require one ton fuel. (judithcurry.com)
Particles and anti-particles have the exact same mass and equal, but opposite charges and magnetic moments; if they are unstable, they have the same lifetime. (scientificamerican.com)