The March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day and shifted its axis.
Melting glaciers can alter Earth's gravity field, scientists have found, a discovery that is shedding light on when Greenland and Antarctica began heavily melting. Knowing the timing of this melting could help climate scientists make better estimates of the potential sea level rise resulting from melting ice pouring off these two massive ice sheets.
Anything that has mass has a gravity field that attracts objects toward it. The strength of this field depends on a body's mass. Since the Earth's mass is not spread out perfectly evenly, this means its gravity field is stronger at some places and weaker in others.
Scientists were investigating the Earth's geoid, or the average gravity field across the globe. Over the past 20,000 or so years, the geoid should have been become rounder just as the planet has —the vast glaciers that once covered large swaths of the continents withdrew at the end of the last Ice Age, and since then the land that was once covered in ice has rebounded without the weight of ice pressing down on it, giving the Earth a more spherical shape.
Whenever I watch videos of Earth from space I’m struck by how thin the atmosphere is. Seen from above, our atmosphere is nothing more than a thin shell, enveloping life on Earth. It looks fragile. For me, it makes it even harder to rationalize polluting the environment or letting carbon emissions run wild when you realize that there isn’t an infinite repository for our industrial scale excreta.