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Space Weather
03/13/09 03:58 PM
The weather outside (the atmosphere) is frightful . . .
Most of us think that weather is confined to the roughly 62 miles of atmosphere above our heads. In fact, as meteorologists will tell you, the majority of the Earth's big time weather events occur in the lowest layer of our atmosphere (called the "troposphere"), which includes about the bottom six miles. When you fly in a passenger jet, you often cruise at about 34,000 feet, or just at the edge of the troposphere and bordering the lowest portion of the stratosphere.
But once you get above 62 miles where the atmosphere pretty much ceases and what we call "space" begins, that's the last of the weather, right? Wrong. Space has its own sort of weather, although it's far different than anything we experience here on terra firma. Most of the "weather" in our region of the solar system consists of various forms of energy emitted by the Sun, most notably what is called the "solar wind."
Much of the solar wind is created by violent bursts of matter and energy that explode off the surface of the Sun in so-called flares that blaze out into space. However, occasionally, the Sun emits a much heftier energy load in the form of a plume, which is a huge mass of ionized gas called a "coronal mass ejection," or CME for short. Think of it as a massive belch, and a very hot one at that. Sometimes one of these huge CMEs targets the Earth, bombarding the outer reaches of our atmosphere with highly energized particles that can disrupt communication and energy technology on our planet's surface. We are protected from the worst effects of a CME by our magnetosphere, a kind of energy field generated by the Earth's magnetic core. Think of "shields" from Star Trek.
However, occasionally, a CME can partially overwhelm this defensive shield. In 1989, for example, a CME greater than the mass of 36 Earths crashed into our magnetosphere at about a million miles per hour. When this occurred, a geomagnetic storm was triggered. One of the signs of "space weather" interacting with the Earth is the appearance of auroras, the multi-colored, ghostly lights that dance across the northern sky, most often seen in Winter. However, during the 1989 event, these auroras could be seen as far south as Texas.
The 1989 geomagnetic storm played havoc with power and communication grids in the northern hemisphere. Canada, in particular, suffered some of the worst impact, leaving about 5 million people in the dark. Nonetheless, even larger geomagnetic storms took place in 1859 and 1921. However, at those times, our dependence on the power grid and telecommunications was far less than today. More of these supersized geomagnetic storms will hit our planet in the future, although nobody can accurately predict just when. Let's put it this way . . . when it happens, you'll probably know it.
So, on occasion, space weather profoundly influences conditions here on Earth. It won't require you to get out your snowblower or flip on the air conditioner, but it might leave you groping for a flashlight.
But once you get above 62 miles where the atmosphere pretty much ceases and what we call "space" begins, that's the last of the weather, right? Wrong. Space has its own sort of weather, although it's far different than anything we experience here on terra firma. Most of the "weather" in our region of the solar system consists of various forms of energy emitted by the Sun, most notably what is called the "solar wind."
Much of the solar wind is created by violent bursts of matter and energy that explode off the surface of the Sun in so-called flares that blaze out into space. However, occasionally, the Sun emits a much heftier energy load in the form of a plume, which is a huge mass of ionized gas called a "coronal mass ejection," or CME for short. Think of it as a massive belch, and a very hot one at that. Sometimes one of these huge CMEs targets the Earth, bombarding the outer reaches of our atmosphere with highly energized particles that can disrupt communication and energy technology on our planet's surface. We are protected from the worst effects of a CME by our magnetosphere, a kind of energy field generated by the Earth's magnetic core. Think of "shields" from Star Trek.
However, occasionally, a CME can partially overwhelm this defensive shield. In 1989, for example, a CME greater than the mass of 36 Earths crashed into our magnetosphere at about a million miles per hour. When this occurred, a geomagnetic storm was triggered. One of the signs of "space weather" interacting with the Earth is the appearance of auroras, the multi-colored, ghostly lights that dance across the northern sky, most often seen in Winter. However, during the 1989 event, these auroras could be seen as far south as Texas.
The 1989 geomagnetic storm played havoc with power and communication grids in the northern hemisphere. Canada, in particular, suffered some of the worst impact, leaving about 5 million people in the dark. Nonetheless, even larger geomagnetic storms took place in 1859 and 1921. However, at those times, our dependence on the power grid and telecommunications was far less than today. More of these supersized geomagnetic storms will hit our planet in the future, although nobody can accurately predict just when. Let's put it this way . . . when it happens, you'll probably know it.
So, on occasion, space weather profoundly influences conditions here on Earth. It won't require you to get out your snowblower or flip on the air conditioner, but it might leave you groping for a flashlight.