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Сosmic radiation
and its effect on various processes
About cosmic radiation (cosmic rays)
Cosmic rays are energetic charged subatomic particles, originating from outer
space. They may produce secondary particles that penetrate the Earth's atmosphere and
surface .
Most primary cosmic rays (those which impact the atmosphere from deep
space) are composed of familiar stable subatomic particles that normally occur on Earth,
such as protons, atomic nuclei, or electrons. However, a very small fraction are stable
particles of antimatter, such as positrons or antiprotons, and the precise nature of this
remaining fraction is an area of active research.
About 89% of cosmic rays are simple protons or hydrogen nuclei, 10% are
helium nuclei or alpha particles, and 1% are the nuclei of heavier elements. These nuclei
constitute 99% of the cosmic rays. Solitary electrons (much like beta particles, although
their ultimate source is unknown) constitute much of the remaining 1%.
The variety of particle energies reflects the wide variety of sources. The origins
of these particles range from processes on the Sun (and presumably other stars as well),
to as yet unknown physical mechanisms in the farthest reaches of the observable
universe.
Changes in atmospheric chemistry
Cosmic rays ionize the nitrogen
and oxygen molecules in the atmosphere,
which leads to a number of chemical
reactions. One of the reactions results in
ozone depletion. The magnitude of
damage, however, is very small compared
to the depletion caused by CFCs
Role in ambient radiation
Cosmic rays constitute a
fraction of the annual radiation
exposure of human beings on the
Earth. For example, the average
annual radiation exposure in
Australia is 0.3 mSv due to cosmic
rays, out of a total of 2.3 mSv
Effect on electronics
Cosmic rays have sufficient energy to alter the
states of elements in electronic integrated circuits,
causing transient errors to occur, such as corrupted data
in electronic memory devices, or incorrect performance
of CPUs, often referred to as "soft errors" (not to be
confused with software errors caused by programming
mistakes/bugs).
This has been a problem in extremely highaltitude electronics, such as in satellites, but with
transistors becoming smaller and smaller, this is
becoming an increasing concern in ground-level
electronics as well.
Studies by IBM in the 1990s suggest that computers typically experience
about one cosmic-ray-induced error per 256 megabytes of RAM per month.
To alleviate this problem, the Intel Corporation has proposed a cosmic ray
detector that could be integrated into future high-density microprocessors, allowing the
processor to repeat the last command following a cosmic-ray event.
Significance to space travel
Galactic cosmic rays are one of
the most important barriers standing in
the way of plans for interplanetary
travel by crewed spacecraft. Since the
intensity of cosmic rays is much larger
outside the Earth's atmosphere and
magnetic field, it is expected to have a
major impact on the design of
spacecraft that can safely transport
humans in interplanetary space.
Cosmic Rays also place a threat to electronics
placed aboard outgoing probes. In 2010, a malfunction
aboard the Voyager 2 space probe was credited to a single
flipped bit, probably caused by a cosmic ray.
Role in lightning
Cosmic rays have been implicated in
the triggering of electrical breakdown in
lightning. It has been proposed that essentially
all lightning is triggered through a relativistic
process, "runaway breakdown", seeded by
cosmic
ray
secondaries.
Subsequent
development of the lightning discharge then
occurs through "conventional breakdown"
mechanisms.
Role in climate change
A role of cosmic rays directly or via solarinduced modulations in climate change was suggested by
E.P.Ney in 1959 and by Robert Dickinson in 1975. In
recent years, the idea has been revived most notably by
Henrik Svensmark; the most recent IPCC study disputed
the mechanism, while the most comprehensive review of
the topic to date states: "evidence for the cosmic ray
forcing is increasing as is the understanding of its physical
principles"
Link:
http://en.wikipedia.org/wiki/Cosmic_radiation
Thank you for your attention =)