[LINK] "Are Super Earths more habitable?"
Dec. 2nd, 2009 09:52 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
rfmcdonaldThe Dragon's Tales Will Baird comes up with the best links. And he a father of two!
This is a new theme. I wonder how long it will take to percolate into the popular consciousness, including in literature? In the 2300AD/2320 roleplaying universe that I'm so fond of, created in the late 1980s, nearly all of the colony worlds had masses and gravities either similar to that of Earth or below that of Earth, in some cases substantially below. The only two exceptions were Dukou, a frozen high-gravity prison planet in the Epsilon Eridani system, and King, a world with gravity three times that of Earth and with an environment so hostile that only huge mineral wealth brought by mining, and even then the life expectancy was only 50 years. Will the ratios of super-Earths to Earths and sub-Earths be reversed in the future?
Astronomers have discovered hundreds of Jupiter-like planets in our galaxy. However, a handful of the planets found orbiting distant stars are more Earth-sized. This gives hope to astrobiologists, who think we are more likely to find life on rocky planets with liquid water.
The rocky planets found so far are actually more massive than our own. Dimitar Sasselov, professor of astronomy at Harvard University, coined the term "Super-Earths" to reflect their mass rather than any superior qualities.
But Sasselov says that these planets – which range from about 2 to 10 Earth masses – could be superior to the Earth when it comes to sustaining life.
[. . .]
The fear today is that too much carbon dioxide in the atmosphere will lead to global warming. Yet too little carbon dioxide in the atmosphere would make Earth a much colder place, and the photosynthetic plants and algae that rely on CO2 would perish. The demise of these oxygen-producing organisms would leave us all gasping for breath.
According to Sasselov, Earth's mass helps keeps tectonics in action. The more massive a planet, the hotter its interior. Tectonic plates slide on a layer of molten rock beneath the crust called the mantle. Convective currents within the mantle push the plates around. For smaller planets like Mars, the interior is not hot enough to drive tectonics.
Super Earths, with a larger and hotter interior, would have a thinner planetary crust placed under more stress. This probably would result in faster tectonics, as well as more earthquakes, volcanism, and other geologic upheavals. In fact, Sasselov says the plate tectonics on Super Earths may be so rapid that mountains and ocean trenches wouldn't have much time to develop before the surface was again recycled.
This is a new theme. I wonder how long it will take to percolate into the popular consciousness, including in literature? In the 2300AD/2320 roleplaying universe that I'm so fond of, created in the late 1980s, nearly all of the colony worlds had masses and gravities either similar to that of Earth or below that of Earth, in some cases substantially below. The only two exceptions were Dukou, a frozen high-gravity prison planet in the Epsilon Eridani system, and King, a world with gravity three times that of Earth and with an environment so hostile that only huge mineral wealth brought by mining, and even then the life expectancy was only 50 years. Will the ratios of super-Earths to Earths and sub-Earths be reversed in the future?
