Study Details Why Super-Earths Have Long-Lasting Oceans

This artist’s depiction shows a gas giant planet rising over the horizon of an alien waterworld.

A newly published study from the Harvard-Smithsonian Center for Astrophysics reveals why oceans on super-Earths, once established, can last for billions of years.
Cambridge, Massachusetts – For life as we know it to develop on other planets, those planets would need liquid water, or oceans. Geologic evidence suggests that Earth’s oceans have existed for nearly the entire history of our world. But would that be true of other planets, particularly super-Earths? New research suggests the answer is yes and that oceans on super-Earths, once established, can last for billions of years.
“When people consider whether a planet is in the habitable zone, they think about its distance from the star and its temperature. However, they should also think about oceans, and look at super-Earths to find a good sailing or surfing destination,” says lead author Laura Schaefer of the Harvard-Smithsonian Center for Astrophysics (CfA).
Schaefer presented her findings today in a press conference at a meeting of the American Astronomical Society.
Even though water covers 70 percent of Earth’s surface, it makes up a very small fraction of the planet’s overall bulk. Earth is mostly rock and iron; only about a tenth of a percent is water.
“Earth’s oceans are a very thin film, like fog on a bathroom mirror,” explains study co-author Dimitar Sasselov (CfA).
However, Earth’s water isn’t just on the surface. Studies have shown that Earth’s mantle holds several oceans’ worth of water that was dragged underground by plate tectonics and subduction of the ocean seafloor. Earth’s oceans would disappear due to this process, if it weren’t for water returning to the surface via volcanism (mainly at mid-ocean ridges). Earth maintains its oceans through this planet-wide recycling.
Schaefer used computer simulations to see if this recycling process would take place on super-Earths, which are planets up to five times the mass, or 1.5 times the size, of Earth. She also examined the question of how long it would take oceans to form after the planet cooled enough for its crust to solidify.
She found that planets two to four times the mass of Earth are even better at establishing and maintaining oceans than our Earth. The oceans of super-Earths would persist for at least 10 billion years (unless boiled away by an evolving red giant star).
Interestingly, the largest planet that was studied, five times the mass of Earth, took a while to get going. Its oceans didn’t develop for about a billion years, due to a thicker crust and lithosphere that delayed the start of volcanic outgassing.
“This suggests that if you want to look for life, you should look at older super-Earths,” Schaefer says.
Sasselov agrees. “It takes time to develop the chemical processes for life on a global scale, and time for life to change a planet’s atmosphere. So, it takes time for life to become detectable.”
This also suggests that, assuming evolution takes place at a similar rate to Earth’s, you want to search for complex life on planets that are about five and a half billion years old, a billion years older than Earth.
Headquartered in Cambridge, Massachusetts, the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.
Publication: Accepted for publication at the Astrophysical Journal
PDF Copy of the Study: The persistence of oceans on Earth-like planets: insights from the deep-water cycle
Source: Harvard-Smithsonian Center for Astrophysics

Technology to recycle all type of plastics without using water

Traditionally, plastic recycling processes involve using a lot of water. In order to avoid this waste, Ak Inovex from Mexico developed a new green technology that doesn't require liquids, and has the capacity to process materials such as styrofoam, polystyrene and ABS (Acrylonitrile butadiene styrene) using the same type of customizable machinery.

The technology developed by Marco Adame, founder of Ak Inovex, can process more than 90 percent of any type of plastic, avoids water waste and reduces production costs by half without reducing the quality of the pellets (small beads of recycled plastic) by avoiding stages with severe changes in temperature.
Marco Adame said than the original process of obtaining recycled beads involves washing and then grinding plastic containers. However, this type of plastic has the distinction of being hygroscopic (when it comes in contact with water it retains moisture at a molecular level), so it has to be dehydrated so it can be crystallized; this involves applying heat at 180º C and then cooling the material with water.
However, the development of AK Inovex performs all this process without water, so it goes directly to the formation of recycled beads. As a result the energy consumption is reduced by half, and also the physical space required to perform the operation is less because the system is smaller. Similarly the production of pellets is of better quality, a situation that makes the recycling process more profitable.
"Ak Inovex has a pending patent registration of the three technologies that integrate the development, which are responsible for cooling the plastic through contact with special walls and form the plastic beads," the founder of the company explained.
The advantage of this technology is its ability to process any type of plastic, such as styrofoam, polystyrene, PET and ABS; the difference lies in the mechanism, because there is a special piece for each type of material. The production capacity of plastic beads is of two tons and the team is currently working on increasing it to ten.
For next year, the company wants to change its business strategy and add an ecological washing machine for plastics that uses a special biodetergent, which will reduce the cost of operation even more.
Marco Adame commented that during their participation in the Cleantech Challenge Mexico, a contest to promote the development of green companies, he had contact with the ALINSA group, which is engaged in the manufacture of environmentally friendly cleaning products using biodegradable chemicals.
After the competition, the two companies started talking and joined efforts with the aim of integrating the ecological washing machine system using degradable plastic substances in less than 28 days without affecting the environment, hence replacing lye, which is the current substance used for washing the materials.

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