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Habitable Zones & Global Climate: June 2020


Hurricanes are one of the most extreme storm systems that occur on Earth, characterized by strong rainfall and fast winds. The terrestrial exoplanets that will be characterized with future infrared space telescopes orbit M dwarf stars.

Uncovering the occurrence rate of terrestrial planets within the Habitable Zone (HZ) of their host stars has been a particular focus of exoplanetary science in recent years.

During the last decade, the relation between activity cycle periods with stellar parameters has received special attention. The construction of reliable registries of activity reveals that solar type stars exhibit activity cycles with periods from few years to decades and, in same cases, long and short activity cycles coexist suggesting that two dynamos could operate in these stars.

Out beyond our solar system, visible only as the smallest dot in space with even the most powerful telescopes, other worlds exist. Many of these worlds, astronomers have discovered, may be much larger than Earth and completely covered in water -- basically ocean planets with no protruding land masses. What kind of life could develop on such a world? Could a habitat like this even support life?

Several years ago, planetary scientist Lynnae Quick began to wonder whether any of the more than 4,000 known exoplanets, or planets beyond our solar system, might resemble some of the watery moons around Jupiter and Saturn.

Tidally locked terrestrial planets around low-mass stars are the prime targets of finding potentially habitable exoplanets.

Recent detection of exoplanets with Earth-like insolation attracts growing interest in how common Earth-like aqua planets are beyond the solar system.

Stellar evolution models predict that the solar luminosity was lower in the past, typically 20-25 % lower during the Archean (3.8-2.5 Ga). Despite the fainter Sun, there is strong evidence for the presence of liquid water on Earth's surface at that time.

The history of the Earth has been marked by major ecological transitions, driven by metabolic innovation, that radically reshaped the composition of the oceans and atmosphere.

Scientists have expanded our understanding of potentially habitable planets orbiting distant stars by including a critical climate component - the presence of airborne dust.

Oxygen first accumulated in the Earth's atmosphere about 2.4 billion years ago, during the Great Oxidation Event. A long-standing puzzle has been that geologic clues suggest early bacteria were photosynthesizing and pumping out oxygen hundreds of millions of years before then. Where was it all going?

This article discussesl a few of the problems that arise in geophysical fluid dynamics and climate that are associated with the presence of moisture in the air, its condensation and release of latent heat.

A common message in use to convey the seriousness of climate change to the public is: "Carbon dioxide levels are higher today than they have been for the past one million years!"

Aquatic biospheres reliant on oxygenic photosynthesis are expected to play an important role on Earth-like planets with large-scale oceans insofar as carbon fixation (i.e., biosynthesis of organic compounds) is concerned.