Science for Thought

Super Earths

Super Earths

This is interesting because it could explain why we live on a planet that's the size it is. I've already talked about these beasts in my essays on exo-planets, which are rocky planets that could support life orbiting nearby stars.

A Super Earth is any exo-planet that's like Earth but much larger in mass and orbiting in the habitable zone of a dwarf star, either like our sun or a red dwarf. Several of these Earth-like planets have been located around nearby stars. Most of these super earth planets have masses from 1.3 to 7.5 times the mass of our planet Earth. It turns out that most Earth-like planets are Super Earth.

Keep in mind that these super sized earth type planets are probably not the same as our planet. They have much higher gravity and thicker atmospheres. They do, on the other hand, have the one thing that makes them candidates for life - liquid surface water. In some cases they are ocean worlds.

Now comes the good part. Since the majority of habitable zone planes are Super Earths, what happened to the Super Earths that formed in our solar system? Why is our solar system different?

These questions have prompted astronomers to come up with an interesting theory about why this is, and the most important conclusion is that our solar system does have a Super Earth. It's considered the 9th planet and it's orbiting the Sun at the extreme edge of the solar system at the outer edge of the Kuiper belt. The evidence for its existence is the fact that the orbital paths of large bodies in the Kuiper belt are slanted outward because of the gravity of this 9th planet. The observations and the subsequent calculations take Neptune's gravity out of this effect.

How did this super-sized planet end up way out there? Astronomers theorize that Jupiter is responsible for this. When our star ignited 4.5 billion years ago, it blew the cloud of hydrogen, helium, ice and fine dust left over out of the way. The ice remained out past the snow line where it was cold enough so that water could remain frozen. Most of the dust began to orbit closer in to the new star, but the ice began to clump together and then attract hydrogen and helium to form gas giants. Jupiter claimed most of this remaining gas and ice and became a behemoth of the new solar system. Because Jupiter had to plow through lots of gas and dust, it slowly spiraled in closer to the sun and kicked any large Super Earth's out, either knocking them into the sun or kicking them out into the Kuiper belt. What this means is that the only Super Earth ended up out there instead of in the inner solar system. Eventually, Saturn, Uranus and Neptune played a dodgem game with Jupiter and ended up pulling Jupiter out of the inner solar system and, in turn, they were kicked out further beyond Jupiter where they are today. What was left of the inner solar system formed Mercury, Venus, Earth and Mars, but since the material left over was depleted, none of these planets are super sized. This makes our solar system unique, at least as far as the solar systems that have been discovered so far.

However, this is only a theory. No 9th planet has been discovered, as yet. But, they are definitely looking for it. It's not easy to spot a dim planet way out at the outer edge of the Kuiper belt. We're talking billions of miles. The only way to find it is to use a very large telescope and search for dimming of bright stars as this 9th planet passes in front of them. Eventually, a direct picture of it will be made. It would have a nearly frozen atmosphere, possibly with hydrogen and helium. However, it should have a rocky mantle and a iron core. It would be Earth-like.

Thanks for reading.