Bacteria are literally everywhere. They can be found on your skin, the table where you eat and the soil under your feet. Some lofty bacteria even live in the clouds where they may be responsible for making it hail, snow or rain.
Hail-making bacteria were described by Alexander Michaud of Montana State University who began studying them after a viscous hail storm. Like any good microbiologist, he grabbed some fresh hail and sampled it for microbes. He discovered that each millilitre (about a one-fifth of a teaspoon) of melted hail contained over 1000 bacterial cells.
Michaud believes the bacterial cells do more than sit in the hail, they may actually help form it. His research showed that these cloud-borne bacteria attract water molecules and cause them then freeze in a process called ice nucleation. This is the first step in making hail and can happen at temperatures as high as -2C. Other researchers theorize cloud bacteria may play a similar role in making it rain or snow. Think of that the next time you are tempted to catch a pop some snow in your mouth. [Wired]