The sun's solar wind plasma is a stream of charged particles ejected from the sun's upper atmosphere. The solar wind interacts with every planet in our solar system. It also defines the border between our solar system and interstellar space.
"The sun's million mile-per-hour solar wind inflates a protective bubble, or heliosphere, around the solar system. It influences how things work here on Earth and even out at the boundary of our solar system where it meets the galaxy," said Dave McComas, Ulysses' solar wind instrument principal investigator and senior executive director at the Southwest Research Institute in San Antonio, Texas. "Ulysses data indicate the solar wind's global pressure is the lowest we have seen since the beginning of the space age." (Source: NASA/JPL/CalTech Ulysses Home Page.)
The solar wind is nothing more than a stream of charged particles flowing outward from the Sun with an average velocity of about 400 km/sec. It is a natural consequence of the Sun being so hot - the corona gas has too much energy to be gravitationally bound to the Sun.
(Source: NASA/GSFC, Imagine the Universe - The Sun.)
Topic Image Source
The Sun’s magnetic field and releases of plasma directly affect Earth and the rest of the solar system. Solar wind shapes the Earth’s magnetosphere and magnetic storms are illustrated here as approaching Earth. These storms, which occur frequently, can disrupt communications and navigational equipment, damage satellites, and even cause blackouts. The white lines represent the solar wind; the purple line is the bow shock line; and the blue lines surrounding the Earth represent its protective magnetosphere. The magnetic cloud of plasma can extend to 30 million miles wide by the time it reaches earth. (View full-size image.) (Source: NASA/ESA/SOHO, the SOlar & Heliospheric Observatory, a project to study the Sun from its deep core to the outer corona and the solar wind.)
Solar radiationLast Updated on 2010-01-24 19:11:07
Almost all of the energy that drives the various systems (climate systems, ecosystems, hydrologic systems, etc.) found on the Earth originates from the sun (Figure 1). Solar energy is created at the core of the sun when hydrogen atoms are fused into helium by nuclear fusion (Figure 2). The core occupies an area from the sun’s center to about a quarter of the star’s radius. At the core, gravity pulls all of the mass of the sun inward and creates intense pressure. This pressure is high enough to force the fusion of atomic masses.
For each second of the solar nuclear fusion process, 700 million tons of hydrogen is converted into the heavier atom helium. Since its formation 4.5 billion years ago, the sun has used up about half of the hydrogen found in its core. The solar nuclear process also creates immense heat that causes atoms to discharge photons.... More »
NASA's STEREO Spacecraft Reveals the Anatomy of Solar StormsLast Updated on 2009-04-14 00:00:00NASA Goddard Space Flight Center (Apr. 14, 2009) – What if solar physicists could predict sun storms with the same accuracy and efficiency that meteorologists predict hurricanes?
FIGURE CAPTION – This artist's animation depicts STEREO's COR1 imager capturing a coronal mass ejection as it erupts from the sun and speeds toward Earth. (Credit: Walt Feimer, NASA's Goddard Spaceflight Center)
In much the same way that satellites allow forecasters to see the inner workings and development of a hurricane from its origins until the moment it reaches shore, NASA’s STEREO spacecraft are now capturing images of solar storms and making real-time measurements of their magnetic fields from the moment they lift off the sun until the moment their pressure waves reach Earth's shores.
Eruptions from the sun’s outer atmosphere, or corona, can wreak havoc on earthly technology. These solar... More »
Solar Wind: First ObservationsLast Updated on 2007-11-26 00:00:00
For much of the 1800’s, scientists suspected that the sun emitted some form of corpuscular matter, because it was difficult to understand how auroral activity could be synchronized with the solar sunspot cycle otherwise.
In 1903, Kristian Birkeland in Norway explained aurora as some kind of medium consisting of a stream of electrons that travels from sun to earth. British physicist Sidney Chapman again raised the idea of solar electron streams in a 1918 paper on magnetic storms. Frederick Lindemann, at Oxford University, pointed out that the negative charge accumulated on the Earth would disrupt the process. Lindemann then suggested that any cloud or stream expelled from the Sun would have to be electrically neutral, containing equal charge from ions and electrons.
The real turning point for the discovery of the solar wind came 25 years later in 1943 when astronomer Cuno Hoffmeister... More »
Drag and drop the content to change the order of featured content. The top nine will be displayed.