题目内容

"Solar wind" is the term scientists use to describe the stream of particles that the sun's corona constantly emits. These solar winds, which consist mainly of hydrogen and helium, are intensely hot. fully ionized plasma. Because of the corona's intense heat, these particles continuously escape the sun's gravitational attraction, flowing away from the sun at extreme velocities. Solar winds, though, are not without variation, because they contain faster and slower moving pockets. For instance, solar winds that originate from streamers are slower moving winds at approximately 300 km/second, as opposed to the winds that originate from corona holes and reach speeds of 800 km/second. As they flow away from the sun. tangential discontinuities and interplanetary shocks form, producing pressure variations. Moreover, researchers also know that solar winds are directly related to geomagnetic storms, auroras, and comets. It is these winds that cause comet tails to bend away from the sun. as Kepler accurately predicted in the early 1600s.

Studies have been done on the effect of solar winds on the planets in the solar system. While all the planets are surrounded by this hot. super-charged plasma, the Earth's magnetic field protects it from the solar wind by deflecting the particles. However, solar winds are responsible for the Earth's magnetosphere, and changes in their speed and direction strongly influence Earth's space environment. As the planet closest to the sun. Mercury endures the main impact of solar winds. If Mercury had an atmosphere, these winds would have stripped it away, leaving the planet bathed in radiation. Though Mars is much further from the sun than Mercury, solar winds have also greatly reduced its atmosphere. While Venus has a substantial atmosphere-100 times denser than ours-solar winds reduce its clouds. It is not just those planets nearest the sun which bear the effects of solar winds: The winds travel far beyond the limits of Pluto. Interestingly. while much is now known about solar winds, scientists still do not fully understand how the gases and particles in the sun's corona reach such high velocities.