New 'Isotopic Evolution' Theory Finally Explains Why Planets Are All So Different in the Solar System
Ever wondered what makes the Earth so different than, say, Jupiter or Saturn?
Why is our planet rocky and covered in water, when other planets are big balls of gas? How does a single solar system produce such a variety of different worlds?
A groundbreaking new theory, known as the "Isotopic evolution of the protoplanetary disk and the building blocks of Earth and the Moon" theory, proposed in a paper published in Nature, suggests that planets are made of different materials depending on the time at which they stopped collecting matter. Essentially, the Earth had a relatively quick cooking time, compared to a world like Jupiter, which received fancy premium material from the sun at a later point in the solar system's development.
It's long been established that all planets began forming at around the same time, as debris around the sun began to clump together and form into hot globules of material.
According to the theory, over time, different planets stopped growing, and no longer received new matter as the sun continued to pump out different elements. The earliest planets to settle, therefore, ended up as plain rocks, but those that continued to form received different kinds of matter as the sun, in its infancy, began spitting out different types of cosmic flotsam.
This theory comes as a result of studying the chemical makeup of various asteroids and meteorites, as well as the materials that make up Earth and Mars. This involved looking closely at angrites and ureilites, two very different kinds of meteors, to spot a connection between them and our own planet when observed at a microscopic level. The study also involved looking at Vesta, a larger and more noteworthy asteroid.
These asteroids and meteors all appear to be made of calcium isotopes; the same material as Earth and Mars. Considering the similarity in the composition of our planet and asteroids that formed while our world was in development, it makes sense that the sun must have been shooting out a different kind of material when our planet finished baking compared with the weird extra ingredients that went into Jupiter.
This makes a certain amount of sense considering another theory that claims that Jupiter started life as a rocky world not unlike our own (if somewhat larger), before releasing gas out from within its core that filled the atmosphere, turning it into a gaseous giant. This theory claims that Jupiter grew in size over time as its larger weight managed to draw in more and more cosmic material, transforming it into a world that doesn't resemble Earth at all.
There's a long way to go before this theory can be confirmed either way, but there certainly does seem to be evidence that suggests that a planet's size in some way correlates with the kind of material that it's made from.
This isn't enough to guarantee cause and effect, but this new theory certainly helps to tie things together in a logical fashion.