The rim of Niagara Falls erodes at four to five feet per year, indicating
that it could not be more than 10,000 years old. Therefore, the earth is
not more than 10,000 years old.
The age of Niagara Falls is not the age of the earth. Geologists
estimate that Niagara Falls originated about 7,000 years ago, sometime
after the end of the last glacial episode. This says nothing about how
old the rest of the earth is, though.
