Heliosphere facts for kids
The heliosphere is a bubble in space "blown" into the interstellar medium (the hydrogen and helium gas that fill the galaxy) by the solar wind. Although electrically neutral atoms from interstellar volume can pass through this bubble, almost all of the material in the heliosphere comes from the Sun itself.
For the first ten billion kilometres of its radius, the solar wind travels at over a million kilometres per hour. As it begins to drop out with the interstellar medium, it slows down before finally stopping altogether. The point where the solar wind slows down is the termination shock; the point where the interstellar medium and solar wind pressures balance is called the heliopause; the point where the interstellar medium, travelling in the opposite direction, slows down as it collides with the heliosphere is the bow shock.
Solar wind
The solar wind is made of particles, charged(ionized) atoms from the solar corona, and fields, in particular magnetic fields. As the Sun rotates once in about 27 days, the magnetic field transported by the solar wind gets wrapped into a spiral. Differences in the Sun's magnetic field are carried outward by the solar wind and can produce magnetic storms in the Earth's magnetosphere.
In March 2005, measurements by the Solar Wind Anisotropies (SWAN) instrument onboard the Solar and Heliospheric Observatory (SOHO) have shown that the heliosphere, the solar wind-filled volume which prevents the solar system from becoming embedded in the local (ambient) interstellar medium, is not axisymmetrical, but is distorted, very likely under the effect of the local galactic magnetic field.
Images for kids
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Energetic neutral atoms map by IBEX. Credit: NASA / Goddard Space Flight Center Scientific Visualization Studio.
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Graphs of heliosheath detections by Voyager 1 and Voyager 2. Voyager 2 has since crossed the heliopause into interstellar space.
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The Sun photographed at a wavelength of 19.3 nanometers (ultraviolet)
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The heliospheric current sheet out to the orbit of Jupiter
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Illustration of the heliosphere as released on 28 June 2013 which incorporates results from the Voyager spacecraft. The heliosheath is between the termination shock and the heliopause.
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The bubble-like heliosphere moving through the interstellar medium.
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ENA detection is more concentrated in one direction..
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Pioneer H, on display at the National Air and Space Museum, was a canceled probe to study the Sun.
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IBEX heliosphere map.
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Overview of heliophysics spacecraft circa 2011.
See also
In Spanish: Heliosfera para niños
