Is the solar system even bigger than you thought? The answer is harder to find than you might expect.
How Do We Define the Solar System?
Or rather, the question is how you choose to define the solar system. Traditionally, we think of it as the Sun (all 864,938 miles of it) and its surrounding planets. By this definition, and the definition of “planet” that stops at Neptune, it has a radius of about 3 billion miles.
How does that compare to other solar systems? Trappist-1, recently discovered and noted for its seven Earth-like planets, is much smaller—because it orbits a dense dwarf star, its farthest known planet is only 6 million miles away. In contrast, Mercury’s own orbit is just shy of 36 billion miles, about six times that.
Another definition one could use is the sun’s magnetic influence; this extends as far as 10 billion miles. For perspective, the only two man-made spacecraft to reach that far are Voyager 1 (12.98 billion miles) and Voyager 2 (10.7 billion miles), and they each took 40 years to achieve that distance.
And what about the other objects that orbit the sun? The Kuiper belt, made up of icy material, extends for 14 billion miles. But that’s nothing—the Oort cloud is even bigger, extending 9.3 trillion miles from the sun. In fact, if we define it as how far the sun’s gravity can influence things, it may be as large as an astounding 20 trillion miles!
You Need to Know What You’re Measuring Before Crunching the Numbers
So the exact definition of the solar system, and thus its size, is open to interpretation; scientists do not have any uniform answer to this question. But no matter how you look at it, it is very large and very humbling for us, here on this tiny little planet called Earth.
Image Source: Wikipedia