WHICH IS THE MOST IMPORTANT BODY IN THE SOLAR SYSTEM?
Even the smallest of heavenly bodies can have an importance out of proportion to their size. From our perspective, perhaps a hitherto unidentified asteroid, or a wayward comet may prove to be one of the most significant objects in the Solar System.
Many thousands of asteroids exist between the orbits of Mars and Jupiter, but hundreds with diameters in excess of a kilometre routinely cross our orbit.
The energy released when one with a diameter of just 15kms crashed into our planet 65 million years ago is believed to have wiped out the dinosaurs. Millions of tons of dust and burning rock were blasted into the atmosphere causing global fires, tsunami waves and climate change.
A similar cause for concern applies to comets, which exist in their millions beyond Pluto, but which may transect our path around the Sun due to the eccentricity of their orbits.
Jupiter merits an entry because of it's sheer size. 1000 times bigger than the Earth, bigger than all the other planets put together, Jupiter's gravity perturbs the orbits of all other bodies which come within its range, including asteroids and comets. Jupiter acts like a giant vacuum cleaner-come-pinball flipper in the Solar System.
It's gravity can divert comets such as mentioned above on to a collision course with us, but Jupiter may also save us, as Jupiter gathers up numerous errant objects which may otherwise hit us. One such was Comet Shoemaker-Levy 9 which crashed into Jupiter in 1994. If the comet had hit us instead, the results would have been catastrophic.
Mention must now be made of our own Moon. Our moon's comparatively large size and closeness has always had a major influence on our planet. Darkness at night would of course be almost absolute without the Moon.
The Moon's gravitational pull creates the tides on Earth, and this may have been crucial in evolutionary terms (by producing a tidal interface thought to be significant in the first emergence of life on to land), Most importantly the Moon's gravity provides stability to our planet's axis of rotation, and without it our seasons would veer from extreme to extreme. Without the Moon, life may not exist here.
It is also time now to mention that most significant of bodies - the Sun itself. The Sun is the star which lends its very name to our star system; the epicentre, where 99% of the mass is accumulated. It dwarfs everything else.
A system like ours exists because of the star at the centre - without it, there would be no revolving planets, moons and comets, no heat, and no light. Given that the sun is the birth mother of the Solar System, its globe is the heart of the Solar System, and its electromagnetic rays are the lifeblood of the Solar System, it seems bizarre that I do not put it first in this category.
In terms of the origins and continued existence of the Solar System, the Sun is, of course, by far and away the most important object; the star which defines the star system. But how does one define importance? Importance varies with perspective. From the perspective of an intelligent being on Triton, that moon, and its planet Neptune, and the Sun, would be deemed the most important of worlds. But we can assume there is no intelligent being on Triton.
Importance is not an objective value; it is a subjective value. Importance can only be related to comprehension and awareness. Without any sentient life to appreciate it, the Sun doesn't matter. No one would know or care that it exists. No one would know anything exists. Nothing matters without consciousness. I would therefore argue the most important body in the Solar System is the one which sustains conscious life which can bestow the quality of 'importance' that is EARTH.