Earth | Blogs
Wednesday, September 28, 2011
Is the Earth’s Magnetic Field Reversing?
There is a weak zone in the Earth’s magnetic field known as the South Atlantic Anomaly and it may indicate that the Earth’s poles are reversing. The Earth’s magnetic field has been weakening since scientists began measuring it almost 200 years ago – it is estimated to be 10% weaker. The Earth’s magnetic field extends 36,000 miles into space and is created by the spinning of the Earth’s core. The Earth’s core is electrically-conductive and acts like an electromagnet. The magnetic field shields Earth from the high-energy radiation given off by the Sun. In the area known as the South Atlantic Anomaly,...
Sunday, April 10, 2011
How Old is the Earth?
My daughter recently asked me, “How old is the Earth?” I thought for bit and guessed 2 billion years old. My rationale was that dinosaurs first roamed the Earth about 200 million years ago, so 2 billion years seemed sufficiently long. I was wrong. Scientists estimate that the Earth is about 4.5 billion years old. To determine the age of the Earth, scientists study rocks and use a process called radiometric dating to determine the age of the rocks. Geologists have discovered rocks that are at least 3.5 billion years old on each of Earth’s continents. In north central Canada, scientists discovered a rock formation...