![]() ![]() This will increase the number of cosmic rays that reach Earth, exacting an unknown toll on our society. ![]() Scientists predict that when the next flip occurs, our planet will be without its protective magnetosphere for a few thousand years. For example, the lodestone-in-a-bowl-of-water trick no longer works if you were to try it today because the field is 35 percent weaker than it was a few thousand years ago. Although no one knows when the next reversal will take place, and we will be powerless to stop it, researchers do know that Earth’s magnetic field has been weakening for thousands of years. These flips occur at random intervals the last full reversal happened about 780,000 years ago. The field disappears for a few thousand years and then re-establishes itself with the poles facing opposite directions. ![]() For one thing, the geologic record tells us that Earth’s magnetism reverses every few hundred thousand years. That said, much about Earth’s magnetic field remains a mystery. The largest effect we see from the solar wind occurs when the magnetosphere channels the charged particles toward the north and south magnetic poles, where they excite atoms and molecules in the upper atmosphere and cause the aurora. Strong solar outbursts, which are driven by the Sun’s magnetic field, could prove lethal to an astronaut in space, but the magnetosphere ensures they don’t harm us on the ground. The magnetosphere it creates around the planet shields us from cosmic rays - charged particles from outer space that can damage electronics - and a steady stream of particles from the Sun known as the solar wind. ![]() It exists because Earth’s rotation causes molten iron in its core to move, creating a “dynamo” that generates the magnetic field.Įarth’s magnetic field is important beyond its use as a handy navigational aid. A compass needle points north because Earth’s interior essentially contains a giant bar magnet, not unlike the one stuck on your refrigerator but about 10 times weaker and much larger. We can’t see magnetic fields the way we see light, but anyone who has played withĪ compass has basic experience with measuring magnetic fields. Maxwell presented the world with the first unified field equations, and “Maxwell’s equations” became the bedrock of electromagnetism, as fundamental for physics as Newton’s laws are to explain gravitation. In 1865, Scottish scientist James Clerk Maxwell first recognized that electricity and magnetism are not separate forces but actually work together, and that light is a form of electromagnetic radiation. They discovered that lodestone placed on a raft in a bowl of water would align in a north-south direction - in other words, with Earth’s magnetic field. On a basic level, humans have had some understanding of natural magnetism since the time of the ancient Greeks. Where does it come from? How does it affect us? Astronomers don’t know, but in recent years they have come to realize how important cosmic magnetism is, and are working to unwind the answers. Although you cannot see it with your eyes, this fundamental force winds through the spiral arms and influences everything from the formation of stars to the galaxy’s structure. There is also a realtime mode that will update to the current time.There is a tangled web of magnetism running across the Milky Way. When you turn the device to landscape mode a wider view is shown with the moons in their approximate positions for the time selected.ĭate, time and location can be changed. You can swipe left and right on the phase view to go backwards and forwards a day. The phase view shows the current view of Saturn itself including the tilt of the rings. These moons are Dione, Enceladus, Iapetus, Mimas, Rhea, Tethys and Titan. Over 440 named features across seven moons are included. The moon's globe can be shown with north or south at the top or inverted to suit different telescope views. The phase can be switched off to show the whole globe more clearly. The feature database is searchable and can move the globe to a searched feature. You can switch to a 'Globe' mode that allows you to spin the moon around to see the whole globe. Saturn Atlas displays the approximate phase, axial tilt and central meridian of the selected moon from your chosen location and time, and renders these on the globe. You can double tap on the labels to get more information about a particular feature. As you zoom in more labels appear as finer detail comes into view. Use pinch and finger gestures to manipulate a 3D globe of one of seven of Saturn's moons. ![]()
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