Originally posted by theomen
The oldest rocks which have been found so far (on the Earth) date to about 3.8 to 3.9 billion years ago (by several radiometric dating methods). Some of these rocks are sedimentary, and include minerals which are themselves as old as 4.1 to 4.2 billion years. Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.
While these values do not compute an age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it). This lower limit is at least concordant with the independently derived figure of 4.55 billion years for the Earth\'s actual age.
if you have a cup of sand, and you leave it outdoors in the wind and rain for as long as you like. it will never sorted into different layers within your lifetime in these \'normal conditions\'
if you have another cup of sand, but this time, you put it into another big glass of water, and you shake it around a bit. and when the particles settly down and sink to the bottom, they\'d be sorted out in layers. and if you leave glass alone outdoors for a few weeks, the water would have evaporated, and and sand at the bottom would be dry.
now imagine that the cup of sand is the size of the earth, and applying the first scenario, then the dating methods will say the earth is billions of years old. (which presents a lot of other problems of which some of the others have already stated)
in the second scenario, if the whole earth is covered with water (which is scientifically possible if all the ice caps melts), then the dating methods cannot be applied because the assumptions that led to the method is wrong.
there are a lot more other established dating methods, but NONE of them take into account the possibility of world wide castrophies such as a Noah\'s flood. so until they can proved that such a flood never happened (which they cannot), then they cannot use the results from their dating methods as facts.