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Ärende: Plasma as the Origin of L
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The Encyclopedia of
Astrobiology, Astronomy, and Spaceflight  

plasma-based life 

Hypothetical life based on what is sometimes called "the fourth state of
matter," plasma. The possibility of such life is a common theme in
science fiction and is often entertained, for example, in episodes of
Star Trek. However, it was given more credence by the announcement in
September 2003 that physicists had succeeded in created blobs of plasma
that can grow, replicate, and communicate, thus fulfilling most of the
traditional requirements for biological cells. Lacking inherited
material they cannot be described as alive, but the researchers believe
these curious spheres may offer a radical new explanation for how life
began. 

Most biologists believe living cells arose out of a complex and lengthy
evolution of chemicals that took millions of years, beginning with
simple molecules through amino acids, primitive proteins and finally
forming an organised structure (see life, origin of). But if Mircea
Sanduloviciu and his colleagues at Cuza University in Romania are right,
the theory may have to be overhauled. They claim cell-like
self-organisation can occur in a few microseconds. 

The researchers studied environmental conditions similar to those that
existed on Earth before life began, when the planet was enveloped in
electric storms that caused plasmas to form in the atmosphere. They
inserted two electrodes into a chamber containing a low-temperature
plasma of argon - a gas in which some of the atoms have been split into
electrons and charged ions. They applied a high voltage to the
electrodes, producing an arc of energy that flew across the gap between
them, like a miniature lightning strike. 

Sanduloviciu says this electric spark caused a high concentration of
ions and electrons to accumulate at the positively charged electrode,
which spontaneously formed spheres. Each sphere had a boundary made up
of two layers - an outer layer of negatively charged electrons and an
inner layer of positively charged ions. Trapped inside the boundary was
an inner nucleus of gas atoms. The amount of energy in the initial spark
governed their size and lifespan. Sanduloviciu grew spheres from a few
micrometres up to three centimetres in diameter. A distinct boundary
layer that confines and separates an object from its environment is one
of the four main criteria generally used to define living cells. 

Sanduloviciu decided to find out if his cells met the other criteria:
the ability to replicate, to communicate information, and to metabolise
and grow. He found that the spheres could replicate by splitting into
two. Under the right conditions they also got bigger, taking up neutral
argon atoms and splitting them into ions and electrons to replenish
their boundary layers. Finally, they could communicate information by
emitting electromagnetic energy, making the atoms within other spheres
vibrate at a particular frequency. The spheres are not the only
self-organising systems to meet all of these requirements. But they are
the first gaseous "cells". Sanduloviciu even thinks they could have been
the first cells on Earth, arising within electric storms. "The emergence
of such spheres seems likely to be a prerequisite for biochemical
evolution," he says. 

This research raises the intriguing possibility that life throughout the
universe could have a very much broader basis than normally recognized.
If plasma-based life can arise naturally, places to look for it could
include the outer layers or interiors of stars, planetary
magnetospheres, HII regions, and even ball lightning. 
   



http://liftoff.msfc.nasa.gov/ academy/universe/how_big_intro.html


The Plasma Universe

More than 99 percent of matter in the Universe exists in the plasma
state though nature rarely produces plasma on Earth's surface. Earth's
electrically neutral environment is a rare exception.  

Plasma processes are important factors in the behavior of stars,
interstellar clouds, comets, the aurora, and even in our upper
atmosphere. If scientists are to fully understand astrophysical and
geophysical phenomena, they first must have a clear understanding of how
matter behaves in the plasma state.

Years before the space era, ground-based radio wave observations
revealed that a region of plasma exists above Earth's electrically
neutral atmosphere. The ionosphere effectively reflects most radio waves
back to Earth, and it is this process that led to the region's
discovery.
 Plasma begins to dominate Earth's environment in the ionosphere.
Ionospheric plasma is very thin and has distinctive layers that differ
in composition and density: the F1 layer (around 200 kilometers) and F2
layer (around 300 to 400 kilometers). In the F2 layer, where the plasma
is most dense, there are rarely more than 1 million electron-ion pairs
in a cubic centimeter (cc), or thimbleful, of space; in comparison, the
neutral gas density for the same region is typically 1 billion particles
per cc. (Neutral gas density at Earth's surface is approximately 10
billion billion particles per cc.) The plasma in these layers,
consisting mainly of electrons and atomic oxygen ions, is sustained by
the ionizing action of solar ultraviolet radiation on the neutral
atmospheric gas. All ionospheric layers tend to merge at night. 

With the advent of artificial scientific satellites, researchers
measuring the characteristics of the space environment near Earth
discovered that Earth's ionized atmosphere extends much higher than was
originally thought. Minute quantities of ionized atmosphere are found in
Earth's magnetopause, which stretches between the lower and denser layer
of the ionosphere (known as the E-layer) and the interplanetary boundary
of Earth's magnetic field. On the side of Earth facing the Sun, the
magnetopause extends upward from 140 to 64,000 kilometers. The behavior
of the gas in this region is controlled by Earth's geomagnetic field,
and the region is, therefore, referred to as the magnetosphere. The
magnetopause trails away from the Sun on the night side of Earth,
forming the magnetotail, which extends well beyond the orbit of the Moon
(more than 384,000 kilometers), and forms a shape similar to a comet's
tail. 

Plasma is strongly influenced by both magnetic and electric forces, and
in turn, plasma particles affect the distribution of magnetic and
electric fields. Beyond the magnetopause, energetic plasma from the Sun
(the solar wind) rushes past Earth at speeds ranging from 300 to 1,000
kilometers per second. While most of this solar wind is deflected around
Earth, some of it penetrates the magnetosphere. The interaction between
the solar wind and the magnetospheric plasma acts like an electric
generator [called the magnetospheric MagnetoHydroDynamic (MHD)
generator], creating electric fields deep inside the magnetopause. These
fields create a general circulation of the plasma (a current system) and
accelerate some electrons and ions to higher energies.

The visible manifestation of the high-energy electrons is seen in the
auroras, the colorful Northern and Southern Lights that appear at 90 to
160 kilometers above Earth. The auroral colors are determined by the
nature of the atoms struck by magnetospheric electrons and the energies
of the collisions: the night sky is painted with the reds and greens of
oxygen and hydrogen and the purples and pinks of nitrogen. 
A typical 3-hour aurora, covering a million square kilometers,
discharges approximately 100 million kilowatt (kW) hours of electric
energy into Earth's immediate environment. 
This is enough energy to power a medium-sized city of 250,000 for nearly
9 days and is roughly equivalent to 6 days of energy output by a large
nuclear power plant. 

By characterizing the magnetic and plasma environments in Earth's
neighborhood, scientists are able to recognize and understand plasma
processes in the rest of the Universe. Already, auroras have been
spotted on Jupiter, and the same types of phenomena appear to occur in
the magnetospheres of Saturn and Uranus.

Many high-energy X-rays and gamma rays detected by astronomical
observations come from magnetized plasmas near stars, galaxies, and
other objects. A visual image of the Universe reveals only the
superficial appearances, but plasma studies will reveal the invisible
structure of space and the processes that may have formed the solar
system from dust and plasma. 

Updated December 5, 1995.




The Fourth State of Matter

There are three classic states of matter: solid, liquid, and gas;
however, plasma is considered by some scientists to be the fourth state
of matter. The plasma state is not related to blood plasma, the most
common usage of the word; rather, the term has been used in physics
since the 1920s to represent an ionized gas. Space plasma physics became
an important scientific discipline in the early 1950s with the discovery
of the Van Allen radiation belts. Lightning is commonly seen as a form
of plasma.
Matter changes state as it is exposed to different physical conditions.
Ice is a solid with hydrogen (H2) and oxygen (O) molecules arranged in
regular patterns, but if the ice melts, the H2O enters a new state:
liquid water. As the water molecules are warmed, they separate further
to form steam, which is a gas. In these classic states, the positive
charge of each atomic nucleus equals the total charge of all the
electrons orbiting around it so that the net charge is zero. Each entire
atom is electrically neutral.

When more heat is applied, the steam may be ionized: an electron will
gain enough energy to escape its atom. This atom is left one electron
short and now has a net positive charge; now it is called an ion. In a
sufficiently heated gas, ionization happens many times, creating clouds
of free electrons and ions; however, not all the atoms are necessarily
ionized, and some may remain completely intact with no net charge. This
ionized gas mixture, consisting of ions, electrons, and neutral atoms,
is called plasma. 

A plasma must have sufficient numbers of charged particles so that the
gas, as a whole, exhibits a collective response to electric and magnetic
fields. Plasma density, therefore, refers to the density of the charged
particles.
Although plasma includes electrons and ions and conducts electricity, it
is macroscopically neutral: in measurable quantities, the number of
electrons and ions are equal. The charged particles are affected by
electric and magnetic fields applied to the plasma, and the motions of
the particles in the plasma generate fields and electric currents from
within. This complex set of interactions makes plasma a unique,
fascinating, and complex state of matter.

Plasma is found in both ordinary and exotic places. When an electric
current is passed through neon gas, it produces both plasma and light.
Lightning is a massive electrical discharge in the atmosphere that
creates a jagged column of plasma. Part of a comet's streaming tail is
plasma from gas ionized by sunlight and other unknown processes. The Sun
is a 1.5-million-kilometer ball of plasma, heated by nuclear fusion (the
picture is seen here in a Solar Max image of the corona, is a plasma
heated by nuclear fusion).

Scientists study plasma for practical purposes. In an effort to harness
fusion energy on Earth, physicists are studying devices that create and
confine very hot plasmas in magnetic fields. In space, plasma processes
are largely responsible for shielding Earth from cosmic radiation, and
much of the Sun's influence on Earth occurs by energy transfer through
the ionized layers of the upper atmosphere. 

"It's uncertain whether intelligence has any long term survival value.
Bacteria do quite well without it."
 Stephen Hawking
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