Extrasolar planets suggest our solar system is unique and young
by Rod Bernitt
More extrasolar planets discovered
The claims that more planets have been discovered in orbit around nearby stars continue
to make the news,1,2
with over 100 now documented.3 A recent
report in Sky & Telescope discloses
‘The new discoveries, like most of the previously known exoplanets, generally
follow eccentric (elongated) orbits and are closer to their stars than the giant
planets in our solar system are to the Sun.’2
Much excitement concerns the star 55 Cancri. Apparently, it has a Jupiter-like planet
orbiting further out—at about 5.9 AU with a mass about 4.05 M_Jupiter. (AU,
stands for astronomical unit, the unit of length for solar-system-scale measurement,
and equals the average distance of the Earth from the sun. The mass unit, M_Jupiter,
is based on the mass of the planet Jupiter, about 318 times the mass of the Earth.)
Because this exoplanet with 55 Cancri exists, so the thinking goes, other exoplanets
must exist much farther out from their host stars. If so, our solar system would
not be unique.
Evolutionists hope that many stars will be discovered with habitable Earth-like
planets and gas-giant planets orbiting far from their host stars—similar to
our solar system configuration. It’s interesting that this latest speculation
has arisen from extrapolating a single observation with both mass and measured orbital
eccentricity (e = 0.16) much greater than Jupiter’s (e = 0.05). The reports
also reveal that 55 Cancri apparently has two other Jovian-mass planets orbiting
much closer (< 0.3 AU). Obviously the planetary system for 55 Cancri is not particularly
similar to our solar system.
Many of the stars reported to have extrasolar planets3 range from spectral
class K2 to F7 (typically red to white) and luminosity class IV–V (subgiants
to main sequence stars). A few spectral class M stars are listed as well as Gliese
types. Our sun plots on the Hertzsprung-Russell (H-R) colour-brightness star diagram
as spectral class G2V. The distances from Earth of parent stars range from 3 to
60 pc4 (10–200 light-years)
with spectral class G stars common and 25–35 pc (80–115 light-years)
distance common. Almost 1/3 of the exoplanets listed have
orbits less than 0.4 AU from their parent stars—inside Mercury’s orbit
if placed in our solar system.
Our solar system is different
A simple statistical analysis of some of the data for the exoplanets listed to date3 yields the following averages:
- Mean semimajor axis, a = 1.24 AU
- Mean eccentricity, e = 0.274 (larger than Pluto’s e = 0.244, the most eccentric
of our solar system)
- Mean mass = 3.295 M_Jupiter
If this average gas-giant planet were orbiting in our solar system it would have
a perihelion, (q) of 0.90 AU and aphelion, (Q) of 1.58 AU and continually cut across
Earth’s orbit. We need to keep in mind that the masses reported are a minimum
estimate, not a maximum.
In our solar system, the average values of the nine planets for the same three properties
are:
- Mean semimajor axis, a = 11.902 AU
- Mean eccentricity, e = 0.081
- Mean mass = 0.156 M_Jupiter
The ‘average’ perihelion, q is 10.938 AU and the aphelion, Q is 12.866
AU, which is well removed from the Earth’s orbit.
NASA/JPL-Caltech
The 55 Cancri system has a Jupiter-mass planet in an orbit similar to the orbit
of our Jupiter. At least one other planet is thought to exist, orbiting at one tenth
the distance between the Earth and our sun.
This makes an interesting comparison. First, the extrasolar planets have much larger
masses than our gas-giant planets. The 4.05 M_Jupiter gas giant at 55 Cancri is
an example. Then, the extrasolar planets orbit much closer to their host stars and
have a greater orbital eccentricity than the planets in our solar system. In fact,
the exoplanets seem to be more similar to double stars, visual binary systems, and
spectroscopic binary systems, than to the planets in our solar system.5 For binary stars the mean eccentricity, e is 0.28 and
the orbital period ranges from 1.0 to 10,000 days.6
It is worth remembering that, for the extrasolar planets reported so far, the method
of detection may favour large gas-giant planets orbiting close to their parent stars.
It is surprising that the characteristics of the extrasolar planets are so different
from the gas-giant planets of our solar system. Surprising because it has been claimed
for decades that the naturalistic evolution model thoroughly explains our solar
system. According to evolution, the rocky, terrestrial planets formed because the
inner solar nebula was hot, while the outer regions of the solar nebula were cold,
forming the gas giants.2 The same characteristics were
expected for the planetary systems of other stars since they supposedly formed the
same way. However, gas-giant planets orbiting less than 0.4 AU from their parent
stars explode this belief. Somehow, evolutionists have avoided publicizing this
issue.
How to explain?
The extrasolar-planet data suggests our solar system is special, which is difficult
to explain from a naturalistic evolutionary perspective. For some reason, when our
solar system formed, the sun managed to avoid the more common ‘fate’
of other star systems. Specifically, we do not have gas-giant planets orbiting from
0.1 to 3.0 AU from the sun, like 75% of the stars with planets so far listed.3 The other planets in our solar system are well clear
of the Earth’s orbit.
Nearby stars of spectral class G, similar to the sun, are expected to be of a similar
age (as determined from the H-R diagram). In fact, 55 Cancri is a spectral class
G8 star and considered to be 4–7 billion years old on the H-R diagram.2 Stars of similar age would have completed a similar number
of galactic rotations7 since their
origin. So, although our sun would have completed some 20 galactic rotations (assuming
the astronomical age of the galaxy is correct), it has somehow managed to avoid
interactions which produced gas-giant planet configurations with orbits near 1.0
AU, the Earth’s location. That’s pretty significant for the survival
of life on earth.
The data is easy to understand from a young-earth creation model. Since Creation
Week ended (Genesis
2:1–3) some 6,000 years ago as measured on earth, the sun and nearby
spectral class G stars have completed much less than one galactic rotation. Certainly,
since Creation Week, these nearby star systems have experienced little stellar evolution.
The creation interpretation affects our understanding of the origin of our solar
system and of extrasolar planets.
I wonder if evolutionists thank their lucky stars and random particle collisions
for the unique configuration of our solar system and our habitable earth. Modern
secularists cannot consider that the Creator had anything to do with it. Such thinking
would violate a central tenet of modern science—methodological naturalism.8
From a creation perspective, God, during the Creation week, predetermined the initial
conditions of our solar system to provide a habitable earth. We know from
Genesis 1:31, that at the end of Creation Week God’s creation was
‘very good’. It is hard to imagine that gas-giant planets orbiting near
the Earth and gravitationally interacting with it would fit the description of ‘very
good’. Such interaction would cause the Earth to become as volcanically active
as Jupiter’s moon Io, even if the orbits were stable.
Thus, the gas-giant planets were created in the outer orbits of the solar system
and the smaller rocky planets in the inner orbits. This has ensured that the earth
has remained stable and habitable because, as explained in
Isaiah 45:18, the Creator formed the earth to be inhabited. Because of its
naturalistic evolutionary philosophy, modern science does not want to recognise
that our solar system is specially created, and so it has problems explaining the
data for exoplanets, which show that our solar system is special, and young.
Related articles
Further reading
References
- AstroNews, Opening the new-planet floodgates, Astronomy
30(9):20–22, 2002. Return to text.
- NewsNotes, The first exo-Jupiters, Sky & Telescope
104(3):20, 2002. Return to text.
- Masses and orbital characteristics of extrasolar planets, <exoplanets.org/almanacframe.html>,
24 September 2002, maintains a growing database on extrasolar planets.
Return to text.
- pc stands for parsec, the unit of stellar distance. One pc is the
distance to a star that produces a parallax of one second of arc on a base line
1 AU long. One pc is 206,265 AU or 3.26 light-years. Return to text.
- Cox, A.N. (Ed.), Allen’s Astrophysical Quantities Fourth
Edition, Springer-Verlag, pp. 424–425, 2000. Return to text.
- Cox, Ref. 5, p. 424. Return to text.
- Bernitt, R.,
Globular clusters and the challenge of blue straggler stars, Journal of Creation
16(2),5–7, 2002; p. 6. Return to text.
- Rennie, J., 15 Answers to Creationists Nonsense, Scientific
American 286(1):78–85, 2002; p. 84. Note, this article
was rebutted; see 15 ways to refute materialistic bigotry: A
point by point response to Scientific American. Return to
text.
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