Tipping Points

Our earth is located in what scientists term the “Goldilocks Zone” because it is “just right.”  If we were not located exactly where we are in the solar system and in the galaxy and in the universe, we probably would not exist.  Extremophiles probably live in hostile environments throughout the universe, but mesophiles, like our species, need a stable and moderate habitat or they cannot survive.

There have been mass extinctions throughout the life of our planet with the Permian extinction having the distinction of killing off the most – about 90% of the species on earth at that time.  Some scientists are concerned that we may be on the brink of a sixth major extinction since plants and animals are dying off anywhere from 100 to 1,000 times faster than they did before humans came on the scene. 

Scientists at Duke University completed a study, published May 29, 2014, in the journal Science, that measured the rate at which species are disappearing from earth.  In 1995, the researchers found that the pre-human rate of extinctions was roughly 1. Now, that rate is about 100 to 1,000.

Stuart Pimm, the study’s lead author, said habitat loss is mostly to blame for the increasing death rates.  As humans continue to alter and destroy more land, animals and plants are increasingly being displaced from their natural habitats.  Climate change is also a factor, he added.

So, with the balancing point of nature being “just right” on our planet, it probably does not take much to tip the balancing scales to one side or the other, which will have devastating effects to those species which cannot adapt in time.

There are many potential tipping points on our planet:  (1) climate change, (2) ocean currents, (3) frozen methane, (4) buried black carbon, (5) permafrost and glacier melt, (6) hydrological cycle, (7) reduced sea ice, (8) draught, (9) bacteria resistant to penicillin, (10) proximity of sun, (11) proximity of moon, (12) volcanic activity, (13) pestilence, (14) movement of asteroid belt, and (15) other things that we may not even see coming, such as black energy and black holes.    

Although global warming focuses on greenhouse gas as the culprit, there are other more significant sources of carbon that would be more dangerous tipping points that would contribute to major climate change that might lead to mass extinctions.  These sources of carbon are black carbon buried in soil, methane frozen in water, and volcanic eruptions.  In fact, the Permian extinction may have been caused by all three of these releases of carbon. 

The most devastating of the three releases may be methane, which has an exponential impact.  As the climate warms, more methane is released.  As more methane is released, it causes our temperatures to go up higher than they would with releases of carbon dioxide.  This melts more methane, causing even higher temperatures with a tipping point being reached with runaway releases like in the Permian period.

Researchers at the University of Wisconsin–Madison, have found that there is black carbon only about six and a half meters below the surface in Kansas, Nebraska, and other parts of the Great Plains where ancient soils are filled with black carbon and plants that have not yet fully decomposed.  These carbon stores could be released into the environment via erosion, road construction, mining, or deforestation.

Erika Marín-Spiotta, a professor at UW-Madison and a coauthor of the study, which was published earlier this week in the journal Nature Geoscience, stated, “It was assumed that there was little carbon in deeper soil.”  Since most soil studies do not penetrate deeper than 30 centimeters, scientists had dramatically underestimated underground carbon reserves that could be released into the air.

Erika explained that carbon reservoirs in buried soils can lurk in a range of environments—under dust accumulation, in floodplains, in valleys, at the foot of slopes of hills and mountains and under lava flows.  She said they are likely to occur in many other parts of the world.

Marín-Spiotta said as much as 5.95 trillion pounds of carbon could be lurking in the depths of the Great Plains area her team looked at.  That’s assuming the ancient soil forms a continuous layer across the region; the researchers were only able to collect measurements from specific points and don’t really know what portion of the region contains the carbon-rich soil.

This giant carbon bomb could be released over the next few decades as we clear cut more forests and see more erosion in draught-prone areas.  We have already seen recent exposure to the atmosphere.  But for the subterranean reserves, Marín-Spiotta believes a number of factors are at work, including how much carbon there really is, how much has persisted since it was buried, and what kind of carbon is down there.

Though Marín-Spiotta says the buried reserves carbon don’t pose an immediate risk to rising carbon dioxide levels in the atmosphere, but land managers need to take precautions, since the researchers found that the ancient soils are more reactive than was previously understood.

As with all tipping points, there can be multiple contributors to the final point of no return.  And these contributors can have exponential effects on each other.  We probably will not know when we have reached the tipping point, but our ancestors will not only know when that tipping point had been reached, but will also suffer the consequences.


Several decades ago, scientists started examining life forms that could survive in extreme environments, called “extremophiles.”  Most extremophiles are microbes, the most primitive of life forms.  Microbes are very good at adapting to extreme environments where more complex life forms would have no chance of survival.

Microbes could have been the earliest life form on earth, living around hydrothermal vents deep in our oceans.  Astrophysicist, Dr. Steinn Sigurdsson, quipped, “There are viable bacterial spores that have been found that are 40 million years old on Earth — and we know they’re very hardened to radiation.”  

In 2013, scientists found bacteria, buried a half-mile deep in a lake under the ice in Antarctica.  This could be analogous to what we may find someday on Jupiter’s moon, Europa, which has a large lake covered with thick ice. 

There is volcanic activity on many moons circling Jupiter and Saturn that could be candidates for harboring extraterrestrial life.  The volcanism is caused primarily by the contraction and expansion of the moons by the gravity of either Jupiter or Saturn.  But one of Saturn’s moons, Tritan, has radiation at its core that is also causing heating and volcanic activity.

These recent discoveries about volcanic activity on the moons have given hope to scientists that there may be primitive forms of life, living near hydrothermal vents on billions of moons throughout our galaxy.  And the universe would be wide open to a great variety of life forms.

Not all extremophiles are unicellular.  Some complex life forms like the Pompeii worm, the Antarctic krill, and phychrophilic Grylloblattidae are also extremophiles.  These forms of life can exist in extreme temperatures or acidity on earth.  They may also be able to survive in the extreme environments on the moons of Jupiter, Saturn, Uranus, and Neptune.

Jupiter’s moons.

Io has volcanic activity caused by strong gravitational tugs during this moon’s elliptical journey passing near Jupiter and its neighbor moon, Europa.  This expansion and contraction of Io creates heat, which fuels a volcanic machine exploding in geysers, spewing straight up for miles and bubbling in pools of lava flows.  Extremophiles are notorious for finding niches near this type of volcanic activity. 

Europa is covered with about ten miles of ice.  Scientists believe that there may be a large body of water under this ice cover, estimated to be up to 100 miles deep containing more water than all of earth’s oceans.  There is a chance that unicellular extremophiles are living in this lake or even more complex animals since this moon has an environment with water, minerals, and a stable climate.  This moon is also likely to have thermal vents from gravitational volcanism.

Ganymede is Jupiter’s largest moon, about twice the size of earth’s moon.  There is evidence that it has a magnetosphere, which probably is produced by liquid water with dissolved electrolytes.  This moon may have a large body of water covered by ice like Europa, providing an environment supporting life.  Furthermore, gravitational volcanic activity would be expected on this the largest moon in our solar system.

Callisto is about 40% ice, most of which is found in the outer covering of the moon.  When meteors have crashed into this satellite, it may have caused fracturing allowing liquid to flood the surface and then freeze as ice.  This may be evidence that there are sources of water under Callisto as well.

Jupiter has about 67 moons, some of which were formed when asteroids were captured by Jupiter’s large gravitational draw.  Some of these moons may also be candidates for life, but we do not know much about them at this time.

Saturn’s Moons

Titan is Saturn’s largest moon, larger than the planet Mercury.  This satellite has an atmosphere made up of nitrogen, methane, and ammonia.  It is a strange environment with methane rain forming rivers and lakes of methane.  Extremophiles may be able to exist in methane even with temperatures at the surface of – 290 degrees F.  This gas rich environment may form a protective covering, allowing extremophiles to survive.

Enceladus is a volcanically active ice moon.  When its volcanoes erupt, ice particles, water vapor, and organic compounds are blasted into orbit and eventually are incorporated into Saturn’s E ring.  Scientists could not understand how Saturn’s outermost ring kept collecting ice particles.  Now they know it comes from Enceladus.  This moon may be another potential environment for extremophiles to live.  The combination of volcanic activity, water, and organic compounds is very compelling for life.

Saturn has over 60 moons and scientists do not have much information on them yet.  However, many of them are icy satellites with a potential for gravitational volcanic activity.  Water and volcanic activity make scientists think of hydrothermal vents in oceans on earth which attract many extremophiles.

Uranus’s Moons

Titania is Uranus’s largest moon, which is about 50% ice.  We know very little about any of the moons circling Uranus, but we speculate that the gravitational pull on these moons would have the same volcanic impact as we know occurs on the moons of the interior planets.  The combination of water and volcanic activity is a recipe for life, especially near hydrothermal vents.

Oberon is the second largest moon on this third largest planet in our solar system.  The density of this moon indicates that about half the moon consists of ice.  The size of this moon, which is only about 34 miles less in width than Titania, along with its potential for volcanic activity may make its environment suitable for life.

There are over 20 moons that we know about that orbit Uranus.  Any of these moons that have similar volcanism and water may also be candidates for having life.  We may find more moons circling Uranus with better telescopes.

Neptune’s Moons

Triton is the largest moon orbiting Neptune.  Triton has water, carbon dioxide, carbon monoxide, methane, and nitrogen that are all frozen at the surface which has temperatures of almost 400 degrees below zero.  There is evidence of volcanic geysers and dark eruptions that interrupt the pinkish “melon skin” of its surface, which is believed to be methane ice.  Life is not impossible on this moon since it has the ingredients of water and volcanism.

We have discovered thirteen moons around Neptune so far, but we expect to find more as our telescopes are improved. 


Is there life on other planets or moons throughout the universe?  Well, with billions of suns in our galaxy and billions of galaxies in our universe, the odds are pretty good that there is primitive life not only scattered throughout our universe, but throughout our galaxy.  Just in our solar system alone, there may be over a hundred moons that could harbor simple life forms.  Earth is probably not very unique in having extremophiles. 

However, our planet may be very fortunate to be located in the “Goldilocks zone” where complex life can develop.  The environment on earth may be “just right” to nurture more complex organisms.  We may have won the lottery by living on a one-in-a-billion planet.  In fact, our planet might be the only planet in the Milky Way Galaxy with environmental attributes perfect for multicellular life. 

But as unique as our environment might be in the Milky Way, there might be billions of similar earths with complex life forms throughout the universe since there are about 170 billion galaxies in our observable universe.  However, the actual number of galaxies currently existing in the universe may be more difficult to determine, since all the galaxies we are viewing are from the past, not from the present.  The galaxies in the deeper fields, which are billions of years old, may not exist today.  We know that galaxies merge with each other, and some may even disappear inside supermassive black holes.

We can only speculate on how many extremophiles exist in the universe.  But it is likely that there is a pretty large number of them, scattered throughout the cosmos and maybe even throughout our solar system.