A coronal mass ejection

Solar wind

The solar wind is made up of charged particles called plasma - mainly electrons and protons - that escape the Sun's powerful gravity and race across the Solar System.

The solar wind is powerful and is believed to have eroded or stripped away the atmospheres of other planets such as Mercury. Earth's relatively strong magnetic and gravitational fields have preserved its atmosphere from the constant onslaught. Observers near the poles sometimes see beautiful lights in the night sky known as auroras, the result of the solar wind interacting with Earth's magnetic field and atmosphere.

Photo: A coronal mass ejection, which is a type of violent solar plasma eruption that disrupts the solar wind (ESA/NASA)

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A coronal mass ejection

About Solar wind

Charged particles race across the Solar System.

About Solar wind

The solar wind is a stream of plasma released from the upper atmosphere of the Sun. It consists of mostly electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in density, temperature, and speed over time and over solar longitude. These particles can escape the Sun's gravity because of their high energy, from the high temperature of the corona and magnetic, electrical and electromagnetic phenomena in it.

The solar wind flows outward supersonically to great distances, filling a region known as the heliosphere, an enormous bubble-like volume surrounded by the interstellar medium. Other related phenomena include the aurora (northern and southern lights), the plasma tails of comets that always point away from the Sun, and geomagnetic storms that can change the direction of magnetic field lines and create strong currents in power grids on Earth.

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