the process which a meteroid undergoes when it enters the Earth's atmosphere. The material of the object is "eaten away" by atmospheric friction, burnt up and/or consumed.


a Mars crossing asteroid


an Earth crossing asteroid


an asteroid that has its entire orbit within that of the Earth


literally "little star", a small body of the solar system with a diameter from about 0.1 to 500 km. Most asteroids orbit the Sun between the planetary orbits of Mars and Jupiter.


literally a "star thrown down"


Central Bureau for Astronomical Telegrams - located at the Harvard-Smithsonian Center for Astrophysics, an organisation responsible for disseminating astronomical discoveries - now done by email and an internet web site.


Charge Coupled Device - an optically sensitive integrated circuit used in video cameras and astronomical electronic cameras


the area of space in a virtual sphere centred on the Earth and with a radius extending to the moon's orbit (literally - on this [the Earth] side of the moon).


a body consisting of a nucleus, a coma and a tail. Low density consisting of volatile material interspersed with dust and other material - sometimes referred to as a "dirty snowball". When a comet comes close to the Sun some of the volatile material is vapourised, released the dust grains.


this literally means "bad star"


(Defense Satellite Program). A group of satellites in geosynchronous orbit to provide the United States Air Force warnings of ballistic missile launches, they also detect very bright fireballs (explosions/implosions) resulting from the entry of a meteoroid into the Earth's atmosphere.


a bright meteor - now defined by the IAU to be a meteor which is brighter than the planet Venus at its brightest (astronomical magnitude -4)


the speed of a (cosmic) body above which it has a kinetic energy greater than the energy it would possess if it was made of pure chemical explosive (eg TNT). This is usually around 4 km/sec.


International Astronomical Union - a body which among other things is responsible for setting standards in astronomy (eg the naming conventions for astronomical objects)


IAU Circulars - issued by the CBAT to quickly notify subscribers of recent astronomical discoveries


the collision of one body with another - (eg an asteroid or comet with a planet) - usually referring to a hypervelocity impact


in astronomical terms the smaller of the two bodies involved in an impact (eg an asteroid or comet)


a catastrophic breakup of an object from the outside in. Pressures on the outside of the object cause it to fragment inwards (the opposite of an explosion). This frequently happens to cometary material that enters the Earth's atmosphere. The results can be similar to an explosion, with a resultant shock wave and a scattering of debris/schrapnel (eventually the pieces that initially travel inwards eventually end up coming out the other side - they are usually burnt up in the atmosphere).


relating to motion (eg kinetic energy is the energy that a body possesses purely because of its speed, and is equal to half the mass of the body times the square of its velocity)


the brightness of a star or other astronomical body. The brightest stars in the night sky have a magnitude of about zero. The faintest stars visible with the unaided (naked) eye have a magnitude of about +6. Other values are:

  • Venus -4
  • Full Moon -12
  • Sun -27
  • Brightest asteroid +6 to +7
  • Limit of 5m telescope about +24
  • meteor

    the visual or radio phenomenon that is seen or detected when a meteoroid enters the Earth's atmosphere. The meteor is not a physical object, but a phenomenon (light, heat or ionisation) that occurs due to the transfer of the kinetic energy of the meteoroid to the atmosphere


    what remains of a meteoroid if it survives the ablation of the entry process through the Earth's atmosphere, and reaches the Earth's surface


    a small body (generally less than about 10m diameter) orbiting the Sun


    Minor Planet Center - colocated with the CBAT - responsible for keeping track of all asteroids - verifying new discoveries and disseminating information about these objects and their discovery


    Near Earth Asteroid - a term for asteroids with orbits that either cross the Earth's orbit or come close to the Earth. There are three orbital classes of NEA: Amors, Apollos and Atens


    Near Earth Object - a term used to include Near Earth Asteroids and also comets that cross the Earth's orbit


    one of the eight or so large bodies of the solar system which orbits the Sun in a relatively circular orbit. Also used for similar bodies that may orbit stars other than the Sun


    another term for an asteroid - not used very frequently at present

    ASAAustralian Space Academy