Understanding the origin of the solar system is fundamental to understanding who we are and where we’re headed. The key lies in understanding time.
Imagine you’re standing over a bathtub full of water, looking down. A bubble slips from around the drain at the bottom and slowly, lazily works it way to the surface. The bubble follows a path through the water, but it takes time to get from the drain to the surface.
Watching the bubble rise is a lot like looking at the light from the stars in the night sky. The light we see is like a bubble – light that was emitted somewhere far back in time and is just now reaching the surface of our eyes.
If the stars are so far away, however, how come we aren’t seeing new stars wink into existence every night? If a star lies 7,000 light years away, for example, how come we don’t suddenly see it today, as opposed to yesterday, when it might have been just one day short of appearing 7,000 years ago?
The answer is twofold. First is that there are new stars forming every day, and we can see their light unfold as they coalesce out of accretion disks. The wiser answer is that the universe is very, very old. The stars that shine in our night sky have been there for billions of years, which means their light has had plenty of time to get here.
It is the very broad age of the universe itself that eventually answers the questions about the origin of our solar system. A recent cosmological model of our evolution has Jupiter, with Saturn in tow, sweeping deeply into the solar system and disrupting the evolution of our rocky planets before zooming out to her current orbit. That would have been, perhaps, four billion years ago.
But where did that rocky matter, and that of Jupiter and Saturn, come from? What was here before the solar system?
The answer lies in the recent discovery of free-floating Jupiter-sized planets beyond the Kuiper Belt. Out there, twenty and more light years away from the sun, drift what is presumed to be twice as many star-free planets as there are stars.
These planets are the remains of solar systems that have been disbanded or destroyed. They are the remnants of systems, perhaps similar to our own, in which the sun has lost its control over their destinies. The suns may have exploded, or imploded, or simply been plundered of their matter by unimagined celestial events.
The end result of these solar system failures is vast fields of gas, dust, planets, planet pieces, moons – of the stuff that makes up a complex solar system. Stuff eject by stars as they die out. And lots and lots of stars have died in the universe’s history.
Our solar system, then, is composed of the remains of other, extinct solar systems. The rock beneath our feet was manufactured in other stars, and may have once orbited still another star.
The key to understanding our origins lies in grasping the immense sweep of time over which the matter around has had to develop. And that development may have had many, many iterations before arriving in our neighborhood to get morphed into the things we understand today. Like the oxygen in the bubble in the bathtub, we can see only the surface, not its history.
To learn more about the discovery of the “loose” planets, take a look at New Survey Suggests there may be more Planets than Stars.