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  • How Big is the Solar System?

    We have all seen artist depictions of the Solar System depicting the Sun and the other planets. There are even illustrations that have the actual sizes fit to scale. However, there is actually no single depiction that artists can render that can give us an actual view as it actually appears. As you might expect, a lot of people have wondered just how big it really is and what its dimensions are.

    Definition

    A simple working definition of what the Solar System is that it is the planetary system composed of the Sun, planets, dwarf planets, and other astronomical objects that are bound by the Sun's gravity. The term can also apply to other planetary systems that have similar characteristics. Such systems may include binary stars, lighter stars, and other heavenly bodies moving in orbit.

    Size and Dimensions

    This question has been asked quite often and scientists have actually come up with different answers. It can be observed however that the actual size of our planetary system depends on how scientists wish to define it. Some scientists will measure the dimensions according to the actual reach of the Sun's gravitational field. Others will define it quite differently, as you might expect.

    There are scientists estimate the influence of our planetary system to extend to a distance of 125,000 astronomical units or AU's. An AU is the equivalent average distance of the Earth to the Sun. It is estimated that the Sun's gravitational field extends to a distance of about two light years outward. Some scientists estimate the said dimensions to be halfway to the nearest star, which is located 4.22 light years away.

    Scientists also believe that another boundary that we can use to measure the Solar System is the heliosphere. This is the region or area where the interstellar medium collides with the solar wind. This region is located to about 95 AU, which is about three times as large as Pluto's orbit.

    Take note that there are no spacecrafts that have ever made it to the heliosphere or heliopause. This basically means we are just estimating the said distance and dimensions the best way we can. That being said, NASA expects the Voyager spacecraft to cross this said region in the next ten years or so.

    Estimates

    To have a good idea of just how big our Solar System is, note that the distance from the Earth to the Sun is already about 93 million miles. Pluto, on the other hand, is located about 40 times that distance. However, do take note that the "edge" of our planetary system does not end with Pluto but it extends a lot further. Remember that comets are also part of our planetary system and they orbit a distance that is about 25 times the distance of Pluto from the Sun.

    Nature