?osmic radiation

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?osmic radiation  and its effect on various
processes
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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.
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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
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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 high-altitude 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.
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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.
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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
solar-induced 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"
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Link
http//en.wikipedia.org/wiki/Cosmic_radiation
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