As well as being the first extra-solar rocky planet discovered, it's also the largest rock we know about, beating out the previous record holder (Earth) by a factor of five.
We've known about a bunch of these super-Earths (1-10 Earth masses) for some time, but there's been some disagreement over whether they were large rocks or small Neptunes. Now we know that large rocky bodies are at least possible, this tells us something interesting about planetary formation.
And these super-Earths have much stronger gravity. And as we all know superman's strength and ability to leap tall buildings was due to the fact that he was from a planet with stronger gravity.
As the character changed over time he gained the ability to fly and became yellow sun powered.
This moment of geeking out was brought to you by comic books!
We've had proof of large rocky bodies for 4.5 billion years. MVEM. Also physical traces of the remains of the planer building, post dust cloud phase(asteroids/comets/impactor sites on every body in the system). Cosmology works under the theory that our local implementation of physical laws is the same elsewhere in the observable universe. What we are finding now at the level of exo planetary bodies is independent confirmation of the local phenomena we have already observed.
We've had proof of large rocky bodies for 4.5 billion years
By large, I mean significantly larger than Earth. We know about rocky bodies up to one Earth mass. We also know about low-density ice-gas bodies of 14 Earth masses or more. Bodies in between these two known types of planet, though, we're pretty ignorant about -- are they Earthlike or Uranuslike? Now, while N=1 makes for lousy statistics, we know that at least this one is Earthlike.
We're actually still astonishingly ignorant about how planets form in the first place, so anything we can find out about the compositions of exoplanets is pretty valuable.
As well as being the first extra-solar rocky planet discovered, it's also the largest rock we know about, beating out the previous record holder (Earth) by a factor of five.
We've known about a bunch of these super-Earths (1-10 Earth masses) for some time, but there's been some disagreement over whether they were large rocks or small Neptunes. Now we know that large rocky bodies are at least possible, this tells us something interesting about planetary formation.