Life on Earth

Fourth week of September 2014, heads of state were in New York City for so called historic UN summit on climate change. They felt that they will bend the course of history and change the future. I want to put my views on life on earth, the climate change, extinction of species and how our kind (humans) do not miss any opportunity to cash such situations politically, financially and some for noble deed laurels.

Climate Change – Another modern opportunity with rational perspective that is worth contemplating. (Reference and data taken from various write up, publications, articles and papers by NASA, ESA, UKSA, ISRO, Harward, MIT, CalTech, University of Cologne and documentaries by Discovery, History Ch, NatGeo, BBC, NHK etc). Imagine the event of big bang, and subsequent formation of earth as a gaseous mass about 13.7 billion year ago. It took nearly 9 billion years for the gas mass to cool and support the first life in form of microorganism.

If the time of Earth’s existence was condensed into a 24-hour clock, the moon formation event occurred just 10 minutes after the Earth was born. The Earth formed 4.56 billion years ago, and the Moon formed about 30 million years later. At that time, the Earth was a magma ocean. An impactor about the size of Mars struck the Earth at an oblique angle, and removed some of the magmatic mantle. This mantle was put in orbit around the Earth, together with some of the debris from the impactor itself, and this material eventually formed the Moon.

When the Moon first formed, it was very close to the Earth. It was possibly only 20 to 30 thousands of kilometers away, and it would have looked extremely large in the sky, at least 20 to 10 times bigger. But there were no living creatures on the Earth at that time to witness this beautiful scene.

The tidal effect of a body increases as a cube of the distance, so the effect of the Moon’s tidal forcing on the Earth was extremely high at this time, to the point that the early magma ocean was affected. This provided some additional energy to the heating from radioactive elements present, but after the radiogenic heating decayed, the Moon still was a source of heating that may have had some geological effect, keeping the Earth’s magma hot and perhaps forcing additional convection in the Earth’s mantle.

After the Earth started to cool, the first crust started to float on top of the magma. During this period the Earth was subjected to increased meteor bombardment. The bombardment had been very intense at the beginning of the solar system and then had started to decline, but about 500 million years after the birth of the Earth, or about 2 hours and 40 minutes into our clock of 24 hours, there was a burst of impactors. This lasted for about hundred million years, and we call this “the late heavy bombardment.” Many of the large basins on the Moon are evidence of this late heavy bombardment period. In this way, the Moon is a history book for the inner solar system and the Earth. NASA have studied these basins with the SMART-1 mission.

The Earth was hit more often than the Moon, however, because Earth is larger and has more gravity. This increased gravity also caused the impactors to be accelerated to higher velocities towards the Earth. That must have been a catastrophic time to be here. So many bombardments would have sterilized the planet. If life had appeared before this period, it would have been extinguished unless it found a way to retreat into niches where it could be protected from these global catastrophes.

When some of these impactors hit the Earth, the explosion caused rocks and dirt from Earth to shoot up and away from our planet. Some of that projected material flew all over the solar system, and some of it landed on the Moon. There could be a few hundred kilograms of Earth material per square kilometer of the Moon’s surface, buried under a few meters of lunar soil. It would be interesting to retrieve those rocks and bring back samples of the early Earth.
Almost nothing from this ancient time period has survived on the Earth because of tectonic recycling of the crust plates or because of atmospheric weathering. We would try to detect some organics within those rocks, and that could tell us about the history of organic chemistry on Earth. Some of these rocks could even have preserved fossils of life. Such rocks could help us look further back into the fossil record, which now stops at 3.5 billion years ago. This way, we could possibly learn about the emergence of life on Earth.

The Moon has been a stabilizing factor for the axis of rotation of the Earth. Looking at Mars, for instance, that planet has wobbled quite dramatically on its axis over time due to the gravitational influence of all the other planets in the solar system. Because of this obliquity change, the ice that is now at the poles on Mars would sometimes drift to the equator. But the Earth’s moon has helped stabilize our planet so that its axis of rotation stays in the same direction. For this reason, we had much less climatic change than if the Earth had been alone. And this has changed the way life evolved on Earth, allowing for the emergence of more complex multi-cellular organisms compared to a planet where drastic climatic change would allow only small, robust organisms to survive and it took nearly 13.7 billion years to evolve.

Now explaining the cyclical alternation of ice and warm periods, mathematician Milutin Milankovitch (1879-1958), calculated the changes in Earth's orbit and the resulting insolation on Earth, Milankovitch became the first to describe that the cyclical changes in insolation is the result of an overlapping of a whole series of cycles: the tilt of Earth's axis fluctuates by around two degrees in a 41,000-year cycle. Moreover, Earth's axis gyrates in a cycle of 26,000 years, much like a spinning top. Finally, Earth's elliptical orbit around the sun changes in a cycle of around 100,000 years in two respects: on the one hand, it changes from a weaker elliptical (circular) form into a stronger one. On the other hand, the axis of this ellipsis turns in the plane of Earth's orbit. The spinning of Earth's axis and the elliptical rotation of the axes cause the day on which Earth is closest to the sun (perihelion) to migrate through the calendar year in a cycle of around 20,000 years: currently, it is at the beginning of January; in around 10,000 years, however, it will be at the beginning of July.

Looking forward, global warming is an inescapable issue for modern age. But 180 years ago, most scientists believed that Earth had been steadily cooling since it was formed. When Louis Agassiz presented the concept of a Great Ice Age to the Swiss Society of Natural Sciences in 1837, his suggestion that the planet had turned colder and then warmed up again was met with skepticism and even hostility, triggering years of fierce scientific debate before the idea was accepted.
Exactly why our planet occasionally cools down has taken more than a century to work out. Now we know that cyclic gravitational tugs from Jupiter and Saturn periodically elongate Earth’s orbit (as calculated by mathematician Milutin Milankovitch), and this effect combines from time to time with slow changes in the direction and degree of Earth’s tilt that are caused by the gravity of our large moon. Consequently, summer sunlight around the poles is reduced, and high, latitude regions such as Alaska, northern Canada, and Siberia turn cold enough to preserve snow year round. This constant snow cover reflects a great deal of sunlight, cooling things down even more, and a new ice age begins. Naturally, this process does not occur with anything like the speed portrayed in the movie The Day After Tomorrow, but geological and other evidence shows that it’s happened at least four times.

But even that warming will not stave off the eventual return of huge glaciers, because ice ages last for millennia and fossil fuels will not. In about 300 years, all available fossil fuels may well have been consumed. Over the following centuries, excess carbon dioxide will naturally dissolve into the oceans or get trapped by the formation of carbonate minerals and along with the facts that our molten iron core that provides us with a magnetic shield against deadly forms of stellar radiation. Such processes won’t be offset by the industrial emissions we see today, and atmospheric carbon dioxide will slowly decline toward preindustrial levels. In about 1,500 - 2,000 years, when the types of planetary motions that can induce polar cooling start to coincide again, the current warming trend will be a distant memory.

This means that humanity will be hit by a one-two punch the likes of which we have never seen. Nature is as unforgiving to mankind as it was to dinosaurs; advanced civilization will not survive unless we develop energy sources that curb the carbon emissions heating the planet today and help us fend off the cold when the ice age comes. Solar, nuclear, and other non-fossil-¬fuel energy sources need to be developed now, and above all deforestation needs to be stopped, before carbon emissions get out of hand. Developed world and few opportunists are playing a prominent part in discovering the technology needed to keep us all going. And while doing so no one wants to miss the bus of opportunities, of fortunes to be made from it.

Epilogue: Our planet has been through a lot worse than us. Been through earthquakes, volcanoes, plate tectonics, continental drift, solar flares, sun spots, magnetic storms, the magnetic reversal of the poles, gravitational pulls of galaxies and other planets … hundreds of thousands of years of bombardment by comets and asteroids and meteors, worldwide floods, tidal waves, worldwide fires, erosion, cosmic rays, recurring ice ages … and will survive many such events. And we think we humans are going to make a difference? The planet isn’t going anywhere. WE are! We need to understand that one day we’re going away. And we won’t leave much of a trace, either. Maybe nothing or traces never to be found… The planet will be here and we will be long gone. Like dinosaurs just another failed mutation. Just another closed-end biological mistake, an evolutionary cul-de-sac. The planet will shake us off like today we see tiger shaking off water.

Saying that, as human, still believe that we should stop deforestation and respect all the living beings on the planet. Live happily and in harmony till we all vanish into oblivion for eternity.