Local Interstellar Cloud

The Local Interstellar Cloud is a low-density region of gas and dust surrounding the Solar System within the local interstellar medium. The Sun and nearby stars move through it.

Interstellar medium: Matter and radiation occupying the space between stars, including gas, dust, and cosmic rays. The cloud is one localized structure within this material between stars.
Solar apex: The direction in the sky toward which the Sun moves relative to nearby stars. The Sun’s motion through the cloud produces a flow of interstellar material past the heliosphere.
Local Bubble: A large, low-density cavity of hot gas surrounding the Sun and many nearby stars. The Local Interstellar Cloud occupies part of this larger cavity.
Voyager 1: A NASA spacecraft launched in 1977 that crossed the heliopause into interstellar space. Its measurements beyond the heliopause sample the local interstellar environment directly.
Local Interstellar Cloud boundary: The uncertain transition between the Local Interstellar Cloud and surrounding interstellar material. Its location determines whether the Solar System is near the cloud’s edge.
Heliosphere: The region around the Sun dominated by the solar wind and its magnetic field. Its boundary separates solar-wind plasma from the cloud’s interstellar environment.
Interstellar helium: Helium atoms and ions in the gas between stars. Neutral helium penetrates the heliosphere and provides a direct tracer of the incoming cloud flow.
G cloud: A nearby interstellar cloud inferred from absorption toward the Alpha Centauri system. Its possible contact with the Local Interstellar Cloud helps map the Sun’s nearby environment.
Voyager 2: A NASA spacecraft launched in 1977 that crossed the heliopause into interstellar space in 2018. Its plasma and magnetic-field data provide a second in situ view beyond the heliosphere.
Interstellar cloud structure: The spatial distribution, density, temperature, and motion of material within interstellar clouds. The cloud’s internal variations are not fully resolved by observations from one Solar System location.

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H I regionBroader topic: It is a nearby example of diffuse interstellar hydrogen, though not fully neutral.