Near the end of the 18th Century the nebular
hypothesis was born. It grew in popularity for more than 100
years and then appeared to die in the early 20th. The cause of
death was said to be contradictory evidence and careful analysis
of the premises, leaving no foundation for its continued
existence. However, after vigorously applying new modifications
of the theory so that black hole physics could also remain
alive, it experienced a resuscitation of sorts and continues
with us to this day.
The hypothesis suggests that the Solar System condensed out of a
cloud of molecular gases and dust in a period measuring billions
of years. Eventually, the dust and gas shrank to the point where
compression heating started a nuclear chain reaction in the
dense ball of hydrogen and helium at the center of the cloud,
giving birth to a new star. As the material continued to be
gravitationally attracted toward the center of the
ever-shrinking mass, it formed a structure called an accretion
disc circling its equatorial plane.
Much like the rings of Saturn, only much more dense and far
larger, the accretion disc extended out beyond the orbit of
Neptune. During the collapse phase of the Solar System's
evolution, according to scientists, eddies and whirlpools of
matter formed in the ring of dust and gas. Those eddies grew
larger as they attracted more material into them, slowly sucking
in larger and larger particles, then pebbles, then boulders,
until hundreds of millions of impacts from nebular condensates
gradually formed the planets.
The theory was later amended in order to explain the origin and
"holding area" for the many comets that enter the Solar System
every year. The Oort Cloud is supposed to be a giant nimbus of
small fragments left over from those early days when the Sun was
a newborn star. It is said to be a spherical region enclosing
the Sun at a maximum radius of about 5 trillion kilometers and
contains billions of objects, some as big as small planets, but
most around the size of a medium asteroid. Closer in to the Sun
is another region of primordial planetoids called the Kuiper
Belt.
The Kuiper Belt theory is the creation of astronomer Kenneth
Edgeworth from Ireland and also separately by American
astronomer Gerard Kuiper in 1951. The first Kuiper Belt Object (KBO)
was discovered in 1992. Sometimes known as "trans-Neptunian
Objects" dozens of KBOs the size of small moon-sized planets
have recently been added to the Solar System's repertoire of
family names.
Eris is the largest KBO, approximately 5% larger than Pluto and
is located 1.4 trillion kilometers from the Sun. Eris has its
own small moon called Dysnomia. Quaoar is about 6 billion
kilometers from the Sun and also revolves in the region of the
Kuiper Belt beyond Pluto's orbit. Quaoar is the third largest
KBO, half the size of Pluto and about as large as Pluto's moon
Charon. The fourth largest KBO yet discovered is Varuna, which
is about 40% as large as Pluto.
After the recent vote by the astronomical community, Pluto is no
longer considered a planet and has been relegated to the status
of KBO, making it the second largest such object in the Solar
System. So, Eris, Pluto, Quaoar, Charon and Varuna are the five
largest Kuiper Belt Objects.
There is a kink in the order and arrangement of the so-called
KBOs, however. An object called Sedna has been discovered in an
orbit that is much farther out than the grouping that includes
Quaoar and Varuna. Sedna is large, about as big as Pluto, but it
is nearly 10 trillion kilometers from the Sun, making it too far
away to technically be considered a Kuiper Belt Object. The
theory has yet to accommodate Sedna other than to say that it
might be from the Oort Cloud and not the Kuiper Belt.
In passing, it must be noted that the
Star Dust cometary mission demonstrated that the existence of comets in such
a far away and frigid nursery as the Oort Cloud was impossible because of the
minerals found in the coma of Comet Wild II. Their presence indicates that the
comet formed in a much hotter environment than what the hypothetical Oort Cloud
could provide.
On January 19, 2006, NASA launched the
New Horizons spacecraft, a mission designed to explore the outer solar
system, including Pluto, Charon and recently discovered
Kuiper Belt Objects. When New Horizons gains its mission objective sometime
in 2015, Electric Universe theorists expect the researchers to be surprised.
Because the nebular hypothesis reached preeminence before scientists realized
that 99 percent of the universe is plasma, the conclusions derived from the
hypothesis are therefore not connected with real observations.
By Stephen Smith