Tag Archives: Neil deGrasse Tyson

Life in the Universe: Part 2. The Evolution of Complex Life


The Evolution of Complex Life

Broken ice flows signal a liquid ocean below

EUROPA: Broken ice flows signal a liquid ocean below.

Microorganisms, or single celled life forms, are hypothesized to be ubiquitous throughout the galaxy. Our own solar system has perhaps six planets and moons which may harbor living organisms. Life leaps into existence even in the most hostile environments and under the most difficult situations. But complex life is a much different matter. There is a wonderful book entitled, Rare Earth: Why Complex Life is Uncommon in the Universe, by Peter D. Ward and Donald Brownlee. This book discusses the long and arduous journey of life from microorganisms to complex life forms. The book defines complex life as meaning animal life.

While microorganisms may be ubiquitous, complex life is exceedingly rare. Our only example of a world supporting complex life is the Earth. From our sample of one body it appears that it takes some four billion years for the evolution of life from microorganisms to complex life forms. And, for the evolutionary process to work, those four billion years must be remarkably stable to allow life to flourish and develop into complexity. The reason that complex life is so rare is that there are so few venues with stable conditions over billions of years.

In the 1961 Frank Drake wrote his famous Drake Equation, which attempts to quantify the number of advanced civilizations in the galaxy. Advanced civilization was defined as a civilization with radio telescopes making interstellar communication possible. In 1984 SETI began scanning the heavens, looking for those advanced civilizations. People such as Carl Sagan used Drake’s basic model and came up with estimates of perhaps 10,000 advanced civilizations.

Now it is believed that the old estimates were wildly optimistic. Now the hypothesis is that because complex life is so difficult to create, Earth may be the only venue for complex life in the galaxy. This hypothesis, the theme of Rare Earth, has been supported by the likes of Stephen Hawking and Neil deGrasse Tyson. The assumption is that the chance of microbial life developing into complex life is so miniscule that the Earth may be the only place where this has happened. If this is true then SETI searches in vain.

Here are some of the requirements for the multi-billion year stability required for life to flourish into complex forms:

  • Complex life cannot exist near the center of the galaxy. A combination of excessive radiation and gravitational perturbations would be too severe for complex live to evolve.
  • Complex life cannot exist anywhere radiation hazards, such as pulsars, which can sterilize planets thousands of light years away.
  • Complex life would be virtually impossible in any binary star system. The gravitational perturbations of a binary star would cause orbital instability, and perhaps cause the planet to crash into another object or to be ejected into the cold darkness of interstellar space.
  • The development of complex life requires a stable solar system with nearly circular planetary orbits. Many of the extra-solar planets that we have discovered have been “hot Jupiters,” formed in the outer reaches of the system and then spiraling inward, smashing lesser planets in the process.
  • The development of complex life requires a planet in the “Goldilocks zone”, at the right distance from its star so as to be neither too hot nor too cold. Moons require similar circumstances that allow for the presence of liquid water.
  • Stars and planets have life cycles. Overtime the Goldilocks zone can move. Originally Venus and Earth were twins, both in the Goldilocks zone, and both most likely had life forms. Over time as the Sun’s radiation increased (10% every billion years), Venus became a hellish world of extreme temperatures and pressures. If there are any life forms now on Venus they would be microorganisms in the upper atmosphere.
  • It is not only the distance from a star that is important, but also the planet’s or moon’s climate. Climate is a complex mixture of atmospheric temperature and pressure, atmospheric composition, transparency, the presence of greenhouse gases, the presence of oceans, carbon cycles which regulate the amount of Co2 in the air, and many more factors as well. As the comparison of Venus and Earth demonstrate, climate is a critical factor in the development of complex life. And this climate must remain essentially stable over billions of years.
  • The development of complex life requires magnetic shielding. Earth is surrounded by a strong magnetic field, caused by a hot, rotating iron core that creates a “force field” surrounding our planet. Mars failed in the development of complex life because it lacked this force field. Mars is smaller than Earth and it cooled more quickly. As the core was solidified the magnetic field collapsed. This allowed the solar winds to strip Mars of most of its atmosphere and water. Also, with the magnetic field removed, there was no protection from intense solar radiation. Earth is protected from radiation not only by our magnetic field bus also by our ozone layer in the atmosphere.
  • Complex life depends upon its home world surviving various extinction events. The Earth has undergone as least five mass extinctions, each of which destroyed at least 75% of life on the planet. Most scientists would say that the Earth is now in the early stages of its sixth extinction event. This time it is caused largely caused by human activity such as agriculture, which destroys eco-systems to create single species dominance, pollution, habitat destruction, and the burning of fossil fuels.

Given all of the impediments to the development of complex life forms, the chance of microorganism evolving into complex life forms is a very small number, and perhaps one in a trillion.

The Rare Earth book stops at complex or animal life. It does not deal at all with the emergence of technological civilizations. There are many intelligent species on Earth such as octopus, pigs, dogs, crows, and dolphins. But none of these species are apt to create civilizations or to build radio telescopes. The leap from complex life to advanced civilization may be as difficult as the leap from microorganisms to complex life.

Celebrity Status and Human Worth


Cosmologist and Science Educator

Cosmologist and Science Educator

America has a very weird way of lifting up the most absurd celebrities.  Justin Bieber was just busted for street racing while drunk and on drugs.  Bieber is also facing felony vandalism charges for an earlier episode where he vandalized a neighbor’s house.

Dennis Rodman just got back from North Korea where he practically gave a lap dance to his “best buddy” Kim Jong Un. Kim Jong Un is the most deranged and oppressive tyrant on the planet. Rodman refused to do anything to encourage North Korea to release of Kenneth Bae.  Rodman said that he was in North Korea to play basketball, not to dabble in politics.  In a CNN interview Rodman even seemed to accuse Bae of crimes against North Korea, and implied that North Korea was justified in holding him.  But research in to Bae’s alleged crime would seem to suggest that Bae’s only crime was to carry a Bible.

We are fascinated by the rich, the famous, the outlandish, and the miscreants.  We track their movement in and out of jail and rehab with intense interest.  Prince Harry can party naked in Las Vegas or dress up in a Nazi SS uniform.  His great-grandfather King George VI, who lead the British fight against the Nazis, must have spun in his grave.

What is wrong with these people and what is wrong with us for being their cult followers?

Let us select and follow celebrities who live lives worth living.  Let us celebrate scientist like Neil deGrasse Tyson who are extending our scientific knowledge.  Tyson is also teaching the masses to appreciate the wonders of the universe.  Let us celebrate people like Jane Goodall for connecting us with nature and working to save endangered species, or Al Gore, who is and trying to save the planet from environmental destruction.  Let us celebrate thoughtful commentators like Bill Moyers or Fareed  Zakaria whose profound insights give us a window on the world and what is happening around us.  Let us celebrate novelists like Jean Auel, who helped illumine our human prehistory through her Clan of the Cave Bear series. Through this series Auel  helps us to understand what it is to be human.

Let us celebrate those who feed the hungry, make great medical advances, those who seek to create sustainable economic systems that can sustain us all into the future, those who work with disaster victims and refugees.

Let us celebrate those who work for peace, for the end of tyranny, violence and oppression.  For those who will work for tolerance in a world full of racial, ethnic, economic and cultural divides.  Let us celebrate those who work to end violence against women, and all the oppression and dehumanization of women because of their gender.

It does not matter what your career or walk of life.  There are actors and rock stars that are great humanitarians, and others that are totally self-absorbed.  Some spend their wealth and celebrity in serving the downtrodden, while the others spend their time in endless hedonism and debauchery without a care in the world.

It does not matter whether you are rich or poor.  It is no great honor to be rich.  Many people became rich through disreputable means.  They do not deserve our honor.  Others became rich by doing great things, inventing new industries, addressing great needs, and making our world a better place to live in many ways.

Jane Goodall

Jane Goodall

Donald Trump may be a billionaire but he is not worth a damn.  The Donald has often been accused of racism.  His political rants , such as his ongoing  “birther” campaign against Obama long after the issue had been settled, make him the laughing-stock of all thinking people.  He is clearly in the game for his own power, wealth and ego.

Author of "Clan of the Cave Bear" series

Author of “Clan of the Cave Bear” series

But others, such as Bill Gates have become world-class philanthropists, using not only their great wealth, but also their global vision, business savvy, and management skills to improve the world.  The Bill and Melinda Gates Foundation is working to eradicate polio, fight the AIDS epidemic, and to create a viable economic system in West Africa, one of the poorest regions of the earth.

The measure of life is not in our acquisitions, whether our treasure be in the form of wealth, power, or fame.  The measure of life is not in our acquisitions but in our contributions.