Posts Tagged ‘sun’

Wakening Sun

I’m interrupting the cosmology story to tell about a wonderful night with the sky.

Friday night (it was really Saturday at 1:30 a.m.) I was awake for some reason, possibly it was the strobing itself. I looked out the north window and saw a brilliant strobe in the northeastern sky. Since I already knew that the sun, long spotless, had recently had some dramatic sunspots, I wondered whether it might be an aurora. It didn’t seem like lightning, because it was so constant, flash, flash, flash — and the sky silent and full of stars.

I wakened my husband, and we both watched — the strobing was going on all across the eastern sky (should have been all across the northern sky, of course) and we wakened the rest of the house and went outside where we were treated to a beautiful show of light, something like an aurora in that it was silent, starry, and strobing from one end of the display to the other, again and again.

But as we climbed the hill south of the house, we were finally able to see over the trees, and there was, in fact, a long line of storm clouds, far to the east. We jumped in the car and drove out to a place where the cornfields didn’t obstruct our vision and watched for half an hour.

The line of storm clouds had to be 40 miles away, or more, thus accounting for the total silence and the locally brilliant stars. As I have said before, clouds low on the horizon do not stand above the landforms you see on the horizon. It was a fantastic display, and not the sort that lends itself to amateur photography, for it was the lighting of the entire horizon, strobe upon strobe, and then starting over again, that was so amazing.

As for the aurora, we have already had one, though it was locally cloudy and invisible. And yesterday, the main force of a coronal mass ejection just missed our little planet. (A coronal mass ejection, CME, is a spout of charged particles. It can be interesting and beautiful; it can damage electronics. Lots of possibilities.) Others solar regions are heating up and could eject so as to send material directly our way. If you want to read more about it, go to spaceweather.com and read what’s going on. You can even subscribe to a spaceweather phone service that will call you if there’s an aurora in your area.

Meantime, here’s an image of the sun that will challenge your concept of its plain surface. Things can look very different when wavelengths other than visible light are used!

Sun, August 7, 2010, with coronal holes that will eject material into space and could (25% chance as we understand things) cause magnetic storms for us.

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So we’ve gone down-size and up-size looking at the sizes of things that produce weather effects on Earth. Now let’s get larger again:

[5] Weather forms in the 60-mile (or 100 km) range include such things as:

  • Simple roll clouds such as we often see crossing the sky. When the sky is too full of clouds to allow free convection up the center of each cloud and down the outside, the clouds combine in long sausage-type rolls which can cross the entire sky, visible for a distance of 60-80 miles. Convection takes air up one one side of the roll and down the other.
  • Lakes such as the Finger Lakes of New York State lie in this size range and definitely affect the weather nearby since tbey produce clouds differently from land, many times bringing rain and snow to lakeside areas.
  • New Zealand has a Maori name that means “land of the long white cloud.” Undoubtedly the first men to arrive in New Zealand from the Micronesian islands to the west found this island because, long before they could see it over the horizon, they could see the clouds that formed above its hills and mountains.

[6] Are there single weather forms in the size range of 1,000 miles?

  • Of course! Hurricanes by whatever name — cyclones or typhoons. These are generally at least a few hundred miles wide, and they can grow to over 1000 miles across.
  • Besides that, the segments of jet stream wind that are over 60 miles an hour are often in the range of 1000 miles across. If you remember that the US is 3,000 miles across, you can readily recognize this size range in the jet stream images.
  • The Sahara desert, 1000 from north to south and three times that from east to west, is the birthplace of the winds that become hurricanes as they cross the Atlantic.
  • The Sahara and other large deserts mark the meeting place of Hadley and Ferrel cells, of which see more below.
  • The Moon, which pulls the tides and in turn gives an impetus to coastal weather, is in this size range.

[7] Our home planet, Earth, is about 8,000 miles in diameter on the large end of the seventh size range (the seventh order of magnitude) which is centered on 6,000 miles.

  • Six massive circulation cells encircle the globe — The northern and southern Hadley cells starting near the equator, the northern and southern Ferrell cells in the middle latitudes, north and south, and the two Polar cells.
  • Between the Polar and Ferrell cells, the world-encircling jet stream journeys on its sinuous path.
  • Of course the oceans fill the atmosphere with the water needed for rain and snow, so they are part of weather.

[8] The size range of our larger neighbor Jupiter is around ten times that of Earth.

  • I don’t suppose you imagine that Jupiter affects our weather, but it might; at least it might have. Because of its large size, it attracts various objects as they enter the solar system, and along with Saturn it protects Earth from most potential invasions by comets and things. When comets do get here, it’s pretty explosive; dust gets into the atmosphere, and clouds and rain follow.It would be fair to say that Jupiter affects the weather by protecting us from more explosive visitations from outer space.
  • But we don’t have to go to Jupiter to find things ten times the size of Earth, for our own magnetic field, particularly as expressed by the Van Allen Belts, is in this size range. The Aurora Borealis is one expression of this belt.
  • Solar flares are in this size range, and seem to be responsible for the massive “winds” of ionized particles that visit Earth when there are sunspots. These not only cause auroras, but the new supply of ionized particles help seed rain clouds. Times of more sunspots and therefore of more flares seem to be related (historically) to warmer times on earth.

[9] The ninth order of magnitude is 100 times the diameter of our earthly home. Nothing that big affects us, right?

  • Except the sun. That’s a weather producer; that’s the weather producer. It builds the Hadley and other major wind cells, evaporates the oceans, heats the deserts, shifts air back and forth between water and land; the sun does everything to keep air and water in motion, and that’s what weather is.

It’s strange to think that such large and distant objects are concerned in the weather in your back yard; do you suppose that anything larger, or from the farther reaches of the universe, affects Earthly weather?

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