Heliophysics
Encyclopedia
Heliophysics is a word coined by Dr. George Siscoe of Boston University and subsequently used by the NASA
Science Mission Directorate to encompass the study of the system composed of the Sun
's heliosphere
and the objects that interact with it—most notably, but not limited to, planetary atmosphere
s and magnetosphere
s, the solar corona, and the interstellar medium
. Heliophysics combines several other disciplines, including several branches of space physics
, plasma physics, and solar physics
. Heliophysics is closely tied to the study of space weather
and the phenomena that affect it. To quote George Siscoe from a recent conference presentation:
Heliophysics is one of four divisions within NASA's Science Mission Directorate (Earth Science, Planetary Science, Heliophysics, and Astrophysics. The word was used to simplify the name of the "Sun Solar System Connections" Division (and before that, the "Sun-Earth Connections" Division). There is some controversy behind the naming of this division, since the base-word "Helio" means sun. The word "Heliophysics" literally means "Physics of the Sun", which, therefore, does not adequately describe the majority of the science that is conducted within the Heliophysics division. NASA uses this in many other ways.
Use of the word heliophysics has also extended to the recent International Heliophysical Year
in 2007-2008.
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
Science Mission Directorate to encompass the study of the system composed of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
's heliosphere
Heliosphere
The heliosphere is a bubble in space "blown" into the interstellar medium by the solar wind. Although electrically neutral atoms from interstellar volume can penetrate this bubble, virtually all of the material in the heliosphere emanates from the Sun itself...
and the objects that interact with it—most notably, but not limited to, planetary atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
s and magnetosphere
Magnetosphere
A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...
s, the solar corona, and the interstellar medium
Interstellar medium
In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...
. Heliophysics combines several other disciplines, including several branches of space physics
Space physics
Space physics, also known as space plasma physics, is the study of plasmas as they occur naturally in the universe. As such, it encompasses a far-ranging number of topics, including the sun, solar wind, planetary magnetospheres and ionospheres, auroras, cosmic rays, and synchrotron radiation...
, plasma physics, and solar physics
Solar physics
For the physics journal, see Solar Physics Solar physics is the study of our Sun. It is a branch of astrophysics that specializes in exploiting and explaining the detailed measurements that are possible only for our closest star...
. Heliophysics is closely tied to the study of space weather
Space weather
Space weather is the concept of changing environmental conditions in near-Earth space or thespace from the Sun's atmosphere to the Earth's atmosphere. It is distinct from the concept ofweather within the Earth's planetary atmosphere...
and the phenomena that affect it. To quote George Siscoe from a recent conference presentation:
Heliophysics is an environmental science, a unique hybrid between meteorology and astrophysics. It comprises a body of data and a set of paradigms (general laws—perhaps mostly still undiscovered) specific to magnetized plasmas and neutrals in the heliosphere interacting with themselves and with gravitating bodies and their atmospheres.
Heliophysics is one of four divisions within NASA's Science Mission Directorate (Earth Science, Planetary Science, Heliophysics, and Astrophysics. The word was used to simplify the name of the "Sun Solar System Connections" Division (and before that, the "Sun-Earth Connections" Division). There is some controversy behind the naming of this division, since the base-word "Helio" means sun. The word "Heliophysics" literally means "Physics of the Sun", which, therefore, does not adequately describe the majority of the science that is conducted within the Heliophysics division. NASA uses this in many other ways.
Use of the word heliophysics has also extended to the recent International Heliophysical Year
International Heliophysical year
The International Heliophysical Year is a UN-sponsored but scientifically driven international program of scientific collaboration to understand external drivers of planetary environments and universal processes in solar-terrestrial-planetary-heliospheric physics. The IHY will focus on ...
in 2007-2008.
See also
- Advanced Composition ExplorerAdvanced Composition ExplorerAdvanced Composition Explorer is a NASA space exploration mission being conducted as part of the Explorer program to study matter in situ, comprising energetic particles from the solar wind, the interplanetary medium, and other sources. Real-time data from ACE is used by the Space Weather...
(ACE) - STEREOSTEREOSTEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...
- WIND (spacecraft)
- Solar and Heliospheric ObservatorySolar and Heliospheric ObservatoryThe Solar and Heliospheric Observatory is a spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on December 2, 1995 to study the Sun, and has discovered over 2100 comets. It began normal operations in May...
(SOHO)