Weegy: fluctuated between hot and cold periods User: Scientists think the earth is approximately _____ years old. 2 billion 3 billion 4 ½ billion 6 ½ billion Weegy: Earth is approximately 4 1/2 billion years old. User: no it not true User: no the earth is not 4 1/2 million or billion it. the earth is 7000 thousnd Weegy: The earth's climate has always changed through history due to natural cycles. Earth's climate has been volatile ... (More)