The heliosphere is the magnetosphere, astrosphere, and outermost atmospheric layer of the Sun. It takes the shape of a vast, tailed bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding interstellar medium. The "bubble" of the heliosphere is continuously "inflated" by plasma originating from the Sun, known as the solar wind. Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating the Milky Way. As part of the interplanetary magnetic field, the heliosphere shields the Solar System from significant amounts of cosmic ionizing radiation; uncharged gamma rays are, however, not affected. Its name was likely coined by Alexander J. Dessler, who is credited with the first use of the word in the scientific literature in 1967. The scientific study of the heliosphere is heliophysics, which includes space weather and space climate.
The Sun photographed at a wavelength of 19.3 nanometers (ultraviolet)
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.
The bubble-like heliosphere moving through the interstellar medium.
Energetic neutral atom (ENA) detection is more concentrated in one direction.
The Sun is the star at the center of the Solar System. It is a massive, hot ball of plasma, inflated and heated by energy produced by nuclear fusion reactions at its core. Part of this energy is emitted from its surface as visible light, ultraviolet, and infrared radiation, providing most of the energy for life on Earth. The Sun has been an object of veneration in many cultures. It has been a central subject for astronomical research since antiquity.
The Sun, filmed through a clear solar filter
High-resolution image of the Sun's surface taken by the Daniel K. Inouye Solar Telescope (DKIST)
The Sun's transition region taken by Hinode's Solar Optical Telescope
During a solar eclipse the solar corona can be seen with the naked eye during totality.