The Earth, Planetary Classifications and Human Activities

The dramatic influence of human activity on Earth could now be pushing our planet into a state of ‘hybridization,’ before it shifts into another planetary class entirely, according to a new study

The dramatic influence of human activity on Earth could now be pushing our planet into a state of ‘hybridization,’ before it shifts into another planetary class entirely, according to a new study.

As scientists continue to search for alien life, many ideas of advanced civilizations are guided by the Kardashev scale, a system first devised in 1964 that sorts these worlds based on the energy their hypothetical inhabitants have harnessed.

In a new study, however, researchers have developed a new classification scheme that takes this even further, relying on the idea that a planet’s energy flow can be pushed out of sync by the beings that dwell on it.

By this system, the experts argue that Earth could be transitioning from a Class IV planet, in which biotic activity has begun to have substantial effects on the energy flow, to the final category, Class V.

In this category, the ‘energy-intensive species,’ has had profound effects.

Earth is now considered to be in a period known as the Anthropocene, an epoch marked by human impact. And, according to the researchers, this activity is even influencing the planet-wide evolution

KARDASHEV SCALE 

The Kardashev scale, named for Soviet astronomer Nikolai Kardashev, was propsed in 1964 to describe a ciilization’s level of technological advancement, based on the amount of energy it harnesses. 

Type I - Civilization could manipulate all the energy resources of its home planet

Type II - Civilization harnesses all the energy in its star/planetary system

Type III - Super-advanced civilization would command the energy of its whole home galaxy

Several extensions have also been proposed over the years, allowing for up to seven categories.

-University of Washington 

NEW PLANETARY CLASSIFICATIONS

Class I - Worlds with no atmosphere at all, such as the planet Mercury and the Earth's moon

Class II - Planets with a thin atmosphere containing greenhouse gases, but no current life, such as the current states of Mars and Venus

Class III - Planets have perhaps a thin biosphere and some biotic activity, but much too little to 'affect planetary drivers and alter the evolutionary state of the planet as a whole.' No current examples exist in the solar system, but early Earth may have represented such a world—and possibly early Mars, if life ever existed there

Class IV - Planets have a thick biosphere sustained by photosynthetic activity and life has begun strongly affecting the planetary energy flow.

Class V - Planet is profoundly affected by the activity of an advanced, energy-intensive species

- University of Washington, via Earth as a Hybrid Planet: Anthropocene in an Evolutionary Astrobiological Context