Line up all eight planets and one of them dwarfs the rest. Jupiter is so enormous that you could pour every other planet inside it and still have room to rattle them around. So how did one planet get to be the undisputed heavyweight champion? The answer starts long ago, with the dust that built everything.

About four and a half billion years ago, there were no planets at all — just a young Sun surrounded by a colossal spinning disk of gas and dust, like a flat pancake of cosmic crumbs. Every planet would be built out of this same swirling stuff. But where you stood in that disk decided what you could grab.

Close to the Sun, it was scorching hot. The only crumbs that could survive there were rock and metal — heavy, stubborn stuff that doesn't melt away. So the inner planets, like Earth and Mars, had to build themselves out of these rare, heavy bits. There just wasn't a lot of it lying around.

But farther out, past an invisible line scientists call the "frost line," it was cold enough for water and other gases to freeze into ice. And there was a HUGE amount of this icy, gassy material — far more than rock ever was. Out there, a baby planet had a giant pantry to eat from.

Jupiter formed just past that frost line — first in line at the all-you-can-eat ice buffet. It quickly snowballed into a big icy-rocky core, much heavier than any inner planet could become. And here's the secret to becoming a giant: the bigger you get, the harder you pull.

Gravity is just the way that heavy things tug on everything around them — and a heavier thing tugs harder. Once Jupiter's core got big enough, its gravity started grabbing not just dust, but the surrounding gas itself. And gas was everywhere out there, in unimaginable amounts.

This kicked off a runaway feast. More gas made Jupiter heavier. Heavier meant stronger gravity. Stronger gravity pulled in even more gas — which made it heavier still. It's a snowball that builds its own bigger snowball, faster and faster, until barely anything is left nearby to eat.

That's why Jupiter is a "gas giant" — it's mostly the lightweight gases hydrogen and helium, the same stuff the Sun is made of, piled up in mountainous amounts. The inner planets never had a chance; they were stuck with the scraps. Jupiter got there first, in the richest spot, and gobbled until it became a near-miss star.

So Jupiter isn't the biggest because it's special — it's the biggest because of where it sat and what it could grab. The right address, an endless pantry of gas, and gravity's snowballing appetite all came together at once. Location, location, location.

And it's still the champion today. If you could somehow weigh the solar system's planets all together, Jupiter alone would outweigh all the others combined — more than twice over. Not bad for a planet that simply showed up early to the buffet and never stopped eating.