NASA Marks Sun-Earth Day with Interactive Webcast

The equinox occurs when the Sun crosses the true celestial equator – the line in the sky above the Earth's equator – from south to north. At that time, day and night are balanced to nearly 12 hours each all over the world and the Earth's axis of rotation is perpendicular to the line connecting the centers of the Earth and the Sun.

The 2009 equinox will occur at 11:44 am at Coordinated Universal Time, marking the beginning of spring in the northern hemisphere and autumn in the southern hemisphere.

During a live, interactive webcast on Friday, participants from around the world and NASA scientists will share new discoveries and visualizations about the Sun.

During the webcast, scientists Eric Christian, Nicky Fox, Terry Kucera and Sten Odenwald will share discoveries about the Sun, while students monitor the Sun and prepare their own space weather forecast.

"Tremendous strides have been made with satellite and ground-based observations of the Sun, which have enabled us to monitor the Sun to gain a better understanding of the processes that govern its influence on our solar system," said Christian, a scientist at NASA's Goddard Space Flight Center in Greenbelt.

Goddard is producing the Sun-Earth Day webcast, which begins at 1 pm EDT, on Friday. For NASA TV streaming video, downlink and scheduling information, click here.

NASA's Jet Propulsion Laboratory in Pasadena, California, and the Adler Planetarium in Chicago will participate in the broadcast. NASA Television and the agency's Web site will broadcast the event live.

NASA collection of solar facts yields some hot insights.

The Sun (Photo courtesy NASA)

For instance, solar flares can sometimes heat the solar surface to temperatures of 80 million degrees Fahrenheit - far hotter that the Sun's core. The core of the Sun is nearly as dense as lead, and has a temperature of 15 million degrees Celsius.

During intense solar flares, astronauts report seeing bright flashing streaks of light that NASA says result from high-energy particles zipping through their eyeballs.

The most powerful solar flare in the last 500 years occurred on September 2, 1859 and was sighted by two astronomers who happened to be looking at the Sun at exactly the right time.

NASA says that a major solar "superstorm" such as the one in 1859 could cost $30 billion a day to the U.S. electrical power grid, and up to $70 billion to the satellite industry.

A little closer to the present, on April 8, 1947, the largest sunspot in modern history reached its maximum size - over 330 times Earth's area.

Even more recently, the fastest coronal mass ejection was recorded on August 4, 1972 and traveled from the Sun to Earth in 14.6 hours - a speed of nearly 10 million kilometers per hour.

Nearly 10 years ago, between May 10-12, 1999, the solar wind nearly vanished, causing Earth's magnetosphere, a highly magnetized region around the planet, to expand in volume by over 100 times.

For the past nine years, NASA has sponsored and coordinated education and public outreach events for Sun-Earth Day that highlight the agency's heliophysics research and discoveries.

NASA's goal is to use celestial events to engage the public and students in kindergarten through 12th grade through webcasts, podcasts, space science activities, demonstrations and interactions with space scientists.

"These events also support the spirit of international collaboration," said Lou Mayo, project manager at Goddard for Sun-Earth Day 2009. "We are excited about sharing the latest discoveries about our Sun and encourage others to join our quest for a greater understanding of our closest star."

This year's theme, "Our Sun, Yours to Discover," celebrates the International Year of Astronomy, particularly daytime astronomy.

Sun-Earth Day is not just limited to one day. It encompasses programs and events throughout the year that culminate in a Sun-Earth Day event on the March equinox.

Copyright Environment News Service (ENS) 2009. All rights reserved.