Friday Headlines, April 26, 2013
THE LATEST IN THE GEOSCIENCES
In recent years, the idea of feathered dinosaurs has become widely accepted. At least when one is referring to theropods dinosaurs like Velociraptor or Tyrannosaurus. Birds are believed to have taken their ancestry from theropods, so it stands to reason that feathers may be shared between the two groups.
Sauropods, the great long-necked dinosaurs, have often been omitted from the feathered fun, in part because they are not directly in line with birds from an evolutionary standpoint, and also, perhaps, because all the big, lumbering mammals that are alive today are relatively hairless.
But when we consider the groups of dinosaurs for which we have evidence of feathers, sauropods come out right in the middle. So while there’s no direct evidence of feathers on sauropods, we might assume that sauropods had them and might have looked like the reconstruction above!
Exoplanets are interesting things. These are planets orbiting some star besides the Sun. We consider them ‘Earth-like’ if conditions on the planet are similar to those of Earth. We consider the composition of the planet itself, and also the possibility of liquid water on the planet, since water is so important to life on Earth. This means we have to think about the size of the planet, how close it is to its star, and the size and intensity of that star. We’re looking for the ‘Goldilocks’ combination of light and warmth that would make the environment just so, and the right size and composition of the planet to provide the correct building blocks for life.
We’ve actually found hundreds of exoplanets, and many that are Earth-like. You can read more about that in this blog post.
NASA’s Kepler mission has found three more Earth-like planets in two different systems. One of those planets, Kepler-62f, is closer in size and composition to the Earth than any other exoplanet known.
Perhaps life is present on one or all of these planets. Perhaps not. Our concept of the Goldilocks zone assumes that all life in the universe must be like life on our own planet.
Is that a good assumption?
I’ve suspected this would happen eventually. It turns out that sometimes our preconceived notions, based upon that which we can observe immediately around us, might be wrong.
On Earth, it appears that the only stable form of magnesium oxide is MgO. This is the only form that we’ve observed. On this assumption, geochemists have drawn conclusions about what minerals are possible on our planet and on others.
Now scientists have predicted stable MgO2 and Mg3O2. These probably exist, but only at high pressures.
What this means is that new minerals are possible in environments of high pressure, say for example, on another planet.
Pressures are not great enough on Earth for these new compounds to exist, but they might exist on other planet in our solar system, or maybe other planetary systems.