Five Things All College Students Should Know About the Earth

The Horn of Africa seen from the International Space Station in January 2015, taken by ESA astronaut Samantha Cristoforetti. NASA. So, another school year starts Thursday (for me) and I thought I'd offer a list of 5 things all college students should know about the Earth, whether they take a geology classes or not (but you really should take at least one). #1 The Earth is 4.54 billion years old (give or take a few million years) This is "long history". About 4.54 billion years ago, the Earth was formed out of the pile of debris and gases that surrounded our just-born Sun. How do we know this? By determining the age of meteorites that match the composition of the early solar system using the isotopes produced by radioactive decay. We can find some evidence of the first minerals produced in the early Earth by dating zircon at the Jack ...