with guest Dr. Phillip J. Erickson, MIT Haystack Observatory
This summer, several monster outbursts have erupted from the Sun. They released clouds of plasma that occupy a volume of space hundreds of times bigger than Earth. These blasts -- called coronal mass ejections -- emanate from active sunspot regions. If Earth were in their path, these huge eruptions could have had devastating effects on our power and communications systems, and on our satellites. Our planet dodged the danger, but the outbursts are a reminder we live with a variable star that can get pretty active from time to time.
We are now headed into a time of increased solar activity. Scientists now have more capability to study and monitor activity on the Sun, including satellites such as STEREO and the Solar Dynamics Observatory. These space-based solar observatories are helping to revolutionize our understanding of our nearest star, and hopefully anticipate and mitigate the influence it has on our planet -- and our technology.
Listen (mp3, 27.9 MB)
Download Transcript (pdf)
Written, narrated and edited by Carolyn Collins Petersen
Soundtrack production and original music by Mark C. Petersen
Produced by Loch Ness Productions for the Astronomical Society of the Pacific
Special thanks to Dr. Phillip J. Erickson
Additional resource materials by Andrew Fraknoi
Fraknoi (Foothill College & ASP)
Although the Sun is 150 million km away from us, the activity in its outer layers has an effect on our planet and our technology. This episode of Astronomy Behind the Headlines introduces us to the energetic atmosphere of our local star and how it can send great gusts of charged particles our way. The effects of such "storms" on the Sun in our neighborhood is often called "space weather," and its ups and downs are now followed by instruments on the ground and in space. As our planet has become surrounded by sensitive electronics aboard satellites and dependent on continent-wide grids for delivering electrical power, we have become increasingly concerned about space weather and its potential for disrupting our activities on Earth.
Carlowicz, Michael & Lopez, Ramon Storms from the Sun: The Emerging Science of Space Weather. 2002, Joseph Henry Press. Popular guide to the Sun’s activity and its effects on Earth.
Odenwald, Sten The 23rd Cycle: Learning to Live with a Stormy Star. 2001, Columbia U. Press. On solar activity and what we on Earth experience.
Poppe, Barbara & Jorden, Kristen Sentinels of the Sun: Forecasting Space Weather. 2006, Johnson Books On how government agencies are cooperating and learning to monitor and predict the Sun’s activity.
NASA mosaic on space weather
Baker, D. & Green, J. “The Perfect Solar Superstorm” in Sky & Telescope, Feb. 2011, p. 28. On the dramatic storm on the Sun in 1859 and how it would affect us today.
Burch, J. The Fury of Space Storms” in Scientific American, Apr. 2001, p. 86. On solar storms and their effects on Earth.
Byrne, J. “Cycle of the Sun” in Astronomy, June 2005, p. 40. On the Sun’s 11-year activity cycle and its causes.
Emslie, A. “Explosions in the Solar Atmosphere” in Astronomy, Nov. 1987, p. 18. Discusses solar flares.
In an image from NASA’s Solar Dynamics Observatory, an active region observed in extreme ultraviolet light burst out with a short-lived M9.3 flare originating from a sunspot on July 29, 2011. Because of the location of the eruption and its sunspot at that time, the associated high-energy particles went wide of Earth and had little terrestrial effects. The region that unleashed the flare possesses the kind of magnetic field characteristics that could produce more solar storms. NASA's Solar Dynamics Observatory continues to keep an ever-watching eye on the Sun for more eruptive events. Credit: NASA/SDO
Frank, A. “Blowin’ in the Solar Wind” in Astronomy, Oct. 1998, p. 60. On SOHO mission results and the Sun’s connection with space weather.
James, C. “Solar Forecast: Storm Ahead” in Sky & Telescope, July 2007, p. 24. On the effects of the Sun’s outbursts and on Earth and how we monitor “space weather.” Nice review.
Odenwald, S. & Green, J. “Bracing for a Solar Superstorm” in Scientific American, Aug. 2008, p. 80. On a huge 1859 storm on the Sun and the dangers of solar hyperactivity. (A similar article appears in the Sept. 2008 issue of Astronomy, p. 34.)
Shrijver, C. “The Science Behind the Solar Corona” in Sky & Telescope, Apr. 2006, p. 28. How we are learning about the outermost atmosphere of the Sun.
Verschuur, G. “The Day the Sun Cut Loose” in Astronomy, Aug. 1989, p. 48. Examines a huge flare.
The Aurora Australis as seen from the Space Shuttle Discovery on STS-39. We see auroras when particles from space hit the Earth's atmosphere near the north and south poles of our planet. (NASA)
Stanford Solar Center (an excellent site with information for students and teachers):
NASA Living with a Star Program -- Background Information on the Sun and Its Effects:
NOAA Space Weather Prediction Center -- Information Pages:
Space Science Institute’s Space Weather Center:
Coronal Mass Ejection as viewed by the Solar Dynamics Observatory on June 7, 2011. The Sun unleashed an M-2 (medium-sized) solar flare, an S1-class (minor) radiation storm and a spectacular coronal mass ejection (CME) on June 7, 2011 from sunspot complex 1226-1227. The large cloud of particles mushroomed up and fell back down looking as if it covered an area of almost half the solar surface. Credit: NASA/SDO
Space Weather (site written by Dr. Sten Odenwald):
Space Weather (site written by Dr. Tony Phillips):
Space Weather FX Vodcasts (mentioned in the interview):
Windows to the Universe -- Space Weather Pages:
Selected Solar Satellite Missions Pages:
Solar Dynamics Observatory: http://sdo.gsfc.nasa.gov/
TRACE (great images & movies): http://trace.lmsal.com/POD//
Observing Changes on the Sun (for serious amateur astronomers; AAVSO):
A 2005 eruption on the Sun (NASA image from the TRACE spacecraft)
Activities and Resources from the SOHO Satellite:
A Family Guide to the Sun (games and activities for elementary school, from the Space Science Institute):
Solar Scapes (middle school activities by Ramon Lopez and Beverly Meier):
On August 1st, almost the entire Earth-facing side of the sun erupted in a tumult of activity. There was a C3-class solar flare (white area on upper left), a solar tsunami (wave-like structure, upper right), multiple filaments of magnetism lifting off the stellar surface, large-scale shaking of the solar corona, radio bursts, a coronal mass ejection and more. This multi-wavelength (211, 193 & 171 Angstrom) extreme ultraviolet snapshot from the Solar Dynamics Observatory (SDO) shows the sun's northern hemisphere in mid-eruption. Different colors in the image represent different gas temperatures ranging from ~1 to 2 million degrees K.
Stanford Solar Center -- Activities about the Sun:
Stanford Solar Center -- Space Weather Monitor Program for Students and Teachers:
Student Observation Network: Tracking a Solar Storm (a series of investigations to help students download and use data to keep track of solar activity):
Yohkoh Satellite Education Site: