An enthusiastic audience attended “Space Weather: Another thing to worry about in our technological society,” a lecture Feb. 24 by Dr. Vahe Peroomian, associate research geophysicist and lecturer in physics and astronomy at UCLA.
Peroomian also has been a member of the college’s board of trustees since 2005 and currently serves as vice president.
Peroomian began with a historical description of the sun as understood by early man. From earliest recorded history the Egyptian, Greek, Indian, Norse and Aztec societies worshiped the sun, which was believed to be a great uniform body sending heat and light to earth.
It was not until the invention of the telescope that observation of the surface of the sun revealed small dark areas which came to be called sunspots. These were described by Galileo in 1612 and contrasted with the previous view of Aristotle that the sun was a perfect body.
Sunspots were then observed over many years and it was noted that during the past 250 years the number of sunspots varied significantly through 11-year cycles. The point of highest activity was called the solar maximum and the lowest the solar minimum. Additionally, solar flares appearing as long flame-like protrusions from the surface of the sun were observed and found to increase in proportion to sunspot activity.
Then, in September of 1859 British astronomer Richard Carrington observed a great solar flare lasting more than five minutes. According to Peroomian “an incredibly short 18 hours later, the largest geomagnetic storm ever recorded occurred, lasting over 24 hours.” At that time the telegraph had been recently invented and operators noticed that the wires were suddenly becoming charged spontaneously, with shorts and fires occuring for no apparent reason.
As later understood, the sun is surrounded by a powerful magnetic field which extends toward the earth. During periods of increased sunspot activity, massive amounts of electromagnetic radiation and high-energy charged particles are ejected from the sun.
Peroomian explained that “solar flares lead to the expulsion of matter into space, often as much as 10 to 15 billion tons. These events are called coronal mass ejections or CMEs. A CME directed toward earth will usually lead to a geomagnetic storm.”
Peroomian displayed photos of the aurora borealis, or northern lights, which he explained is caused by charged particles coming from the sun and interacting with upper atmosphere gas in the earth’s magnetosphere.
Depending on the particular gas (nitrogen or oxygen) an aurora of various colors (red, blue or green) would be visible. Normally this is seen at polar latitudes, however during periods of increased solar activity the aurora may be seen at lower latitudes, including Glendale.
Peroomian is an accomplished photographer and displayed a photo he took of such a local occurrence of an aurora. He has photographed widely on his travels and his photographs can be accessed at www.vahep.com.
Peroomian went on to discuss some important effects of unusually strong solar particle ejections and how this may affect the earth’s environment. This interaction is termed “space weather” in contrast to the more familiar effect of solar heat and visible radiation which produces “weather” as traditionally understood.
According to Peroomian, x-rays traveling at the speed of light “reach earth in eight minutes and impact earth’s atmosphere, energizing and ionizing atmospheric particles. Short wave communications are disrupted for minutes to hours. Next to arrive are solar energetic particles (SEPs) – which reach earth in several hours and are mainly deposited in the polar regions. Large-scale radio blackouts, called polar cap absorption events, occur and last for days.” As the full impact of the geomagnetic storm is felt, auroral displays are seen at much lower latitudes than normal.
Electric power grids are vulnerable to disruption from such events. Millions lost power during a geomagnetic storm in March 1989 affecting the Quebec power grid. Damage to transformers from similar events could be so severe and widespread that “recovery would require years” Peroomian said.
According to Peroomian, a 1997 geomagnetic storm caused failure of the ATT Telstar satellite, nearly preventing broadcast of the Superbowl. “The satellite industry is estimated to generate revenue of $225 billion annually; a single solar storm similar to that of 1859 could cause satellite losses of $30 to 70 billion.”
Peroomian warned that “passengers and crew on transpolar flights can receive a radiation dose that exceeds the radiation exposure limit.” He further noted that “An August 1972 solar particle event would have delivered a lethal dose to Apollo astronauts in less than 10 hours.”
GPS and other navigation systems can be disrupted by solar activity, seriously affecting operations of airlines and shipping.
According to Peroomian “The Space Weather Prediction Center at the National Oceanic and Atmospheric Administration (NOAA) has subscribers in the navigation, satellite, electric power and airline industries that receive magnetic storm warnings” however, “with only a less than 25 percent chance of correctly predicting the occurrence, and a smaller chance of predicting the severity of a storm, many vulnerable systems do not respond to space weather alerts.”
The sunspot cycle is now at the solar minimum.
Further research by Peroomian and others in this field is considered important in order to improve the ability to predict space weather as solar activity increases to a maximum in 2012.