Our Unique Planet
To be able to support life, a planet needs special galactic
conditions, a special place within the galaxy, a certain type of star that it orbits at the right distance
from it, a moon with the right size and distance, a certain tilt, mass, and element composition, a certain
speed at which it rotates, and more. The planet earth has got it all!
The Sun and the Milky Way
· The Milky Way
is a spiral galaxy not in collision.
· The Sun is in a
low concentration of stars.
· The galactic
region has a high local density of metals.
· The Sun’s mass
ensures a nominally constant energy output for at least 5 billion years.
The Earth has:
metal elements from which the complex molecules of life can arise
· Relatively low
carbon content – to avoid a heat-trapping CO2-rich
· Relatively low
water content – to allow dry land as well as oceans
· Rotating molten
iron-rich core to induce radiation-shielding magnetic field
· Mass which
enables an oxygen-rich atmosphere (rather than hydrogen which is too
· Plate tectonics
producing continental drift, mountain chains, diverse climates and therefore a diverse
· A nearly
circular orbit enabling fairly constant solar input all year round
· Distance from
the sun to enable sufficient warmth and light for photosynthesis but prevent tidal
· Huge planets on
the outer edges of the planetary system to be shielded from devastating meteor
· No huge planets
nearby which would interfere with its orbit, gradually driving it into the
· Moderate tilt
to ensure more uniform north-south distribution of solar radiation
· Short planetary
rotation enabling all-around distribution of incoming solar radiation
· A large moon
enabling tidal mixing
Our universe and planet are special indeed. The
likelihood of finding all the above-listed conditions – a life-supporting galaxy and solar system, as well as a
life-nurturing planet – anywhere in the universe has been estimated to be one chance in
1018. With the estimated
number of stars in the visible universe being about 1022, this means the possibility of about
104 or 10,000
earth-like planets circling a sun-like star. With about 1011 galaxies in the visible universe, there
would be an average of one earth-like planet per 10 million galaxies!
Our abode – this special “blue planet” – in the whole vast universe
has all the markings of being the product of design – divine intervention in the development of
Based on: God According to
God, Chapter 3, by Gerald L. Schroeder (HarperOne, New York, 2009).
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