Perspective of humankind in time and space

This page is split into 3 sections:

  1. Our place in the Universe -- how many galaxies, stars, and planets there are
  2. Our place in time -- a timeline of our special planet Earth (an easier to understand section)
  3. The key responsibility of our generation in the survival of life on Earth

1. Our place in the Universe

Our galaxy has approximately 100 billion stars (suns).
100,000,000,000 stars.
Our galaxy, which we mammals named “the Milky Way”, is an ordinary galaxy.

Beyond our galaxy, there are approximately a trillion other galaxies in the Universe.
1,000,000,000,000 galaxies.

Our galaxy, the Milky Way Galaxy, is the first photo shown below. Our sun is shown on this image at a location below the center, in a suburb out on a spiral arm. Our solar system orbits the center of the Milky Way once per 230 million years.

Our galaxy is just one out of approximately a trillion other galaxies.

Photo credits:
Map of our Milky Way Galaxy: NASA/Adler/U. Chicago/Wesleyan/JPL-Caltech.
Multiple galaxies: ESA/Hubble & NASA, F. Pacaud, D. Coe

If we estimate averages, each galaxy has roughly 100 billion stars (suns), more or less.

Altogether, there are approximately 100,000,000,000,000,000,000,000 stars (suns) in our Universe.
That is:
1,000,000,000,000 galaxies x 100,000,000,000 stars/galaxy
= 100,000,000,000,000,000,000,000 stars (suns)

Each typical star has many planets.

There is surely a lot of alien life out there, very unlike us, so try to imagine that …

Some of that is vastly more intelligent and powerful than us primates ...

… and has created far greater artificial intelligence (AI) …

However, Earth is a very special and lucky planet, discussed later in this article. Before getting to that, we also need to understand about our place in time.

The above discusses our place in space. What about time?

Our time in Earth's history

The Earth is around 4.5 billion years old. To picture this in an easy to understand way, imagine drawing a straight line 4,500 km long (2,800 miles) across the continental USA, from the northeast corner to the southwest. The continental USA happens to be approximately 4500 km wide from the edge of the far northeastern state of Maine around the border with the Atlantic Ocean and Canada, to the western side of the state of California near the Pacific Ocean. On this line, mark each year on that line, equally spaced, all 4.5 billion years. What you get is that each year of Earth’s existence would be just 1 millimeter long (0.04 of an inch, or 25 years per inch). Yes, 4,500,000,000 years is a very, VERY long time, which many humans have difficulty understanding well, whereby this "timeline" measurement may help people picture such a long time.

(This photo image is my own.)

Source of underlying public domain map: U.S. Geological Service, via Wikipedia.

Life on Earth advanced and diversified relatively recently in Earth’s history. Notable points on the timeline above are discussed below, plus recent events which would be much too small to display on a timeline that wide.

Earth's atmosphere started as mostly carbon dioxide, with just a very small trace of oxygen, but the emergence of photosynthesis and cellular life resulted in the carbon dioxide levels falling and oxygen levels rising over the billions of years, which made the planet cooler.

The first evidence of life on Earth appears around 3.7 billion years ago. (There are no fossils, there is just the presence in rocks of a type of carbon molecule which is produced by some microscopic living matter.)

Life on Earth was only microscopic for billions of years, i.e., there were neither plants nor animals, just the evolution of life to eventually become cells, each cell being a separate organism. They lived in the oceans. Multicellular organisms started didn't start emerging until less than a billion years ago. Sexual life, which is the mixing of genes from two different organisms, also emerged around a billion years ago, which started rapid diversification.

"Snowball Earth" is a time period in which Earth's surface was almost completely frozen or slushy, from poles to equator, approximately 700 million years ago, for a duration of around 50 million years, though there was still a liquid ocean underneath. This was due to the low carbon dioxide levels in the atmosphere. Photosynthesis over the previous very long time had dramatically lowered the carbon dioxide levels of Earth's atmosphere from very high to much less than 1% (it is now 0.04%), compared to 96.5% Venus and 95% on Mars. (It is possible that much life in this Universe might suffocate itself over time by a similar process, their breathable air just running out.)

Atmospheres on planets normally don't have oxygen (except a trace). Photosynthesis is when life uses the energy of sunlight to combine carbon dioxide and water to make chemicals for energy and energy storage (such as sugars and carbohydrates) for their metabolism, and build structures for their own body. The process of photosynthesis creates oxygen as a waste product, so oxygen levels increased in the atmosphere. It was slow, but it kept adding up over such a long time, until oxygen levels far exceeded carbon dioxide levels.

Carbon dioxide traps some of the heat of sunlight, which helps make Venus very hot. As photosynthetic life thrived on Earth, the Earth cooled from the start of life more than 4000 million years ago to "Snowball Earth" around 700 million years ago, as carbon dioxide levels dropped slowly and oxygen levels rose over time, until life had converted nearly all the carbon dioxide into oxygen around 700 million years ago. Photosynthetic life nearly "ran out of gas" and the Earth had become very cold, with the surface water turning mostly into ice.

Fortunately, new carbon dioxide was released from deep underground by volcanoes before Snowball Earth became completely iced. The volcanoes were in turn caused by plate tectonics. According to geological records, the time period around 700 million years ago during Snowball Earth appears to have been a period of low volcanic activity. Later, the carbon dioxide released by increased volcanic activity led to the Earth starting to warm up again whereby the ice coverage started retreating from the equator, around 660 million years ago. It's not difficult to imagine photosynthesis on a planet with less volcanic activity eventually suffocating due to formation of an ice layer on top which blocks sunlight completely. Venus and Mars have no plate tectonics, and Earth's plate tectonics is thought to be due to Earth's unusually large Moon which causes strong tidal forces. The Moon might have played a crucial role in how far life on Earth evolved.

(Our atmosphere is now approximately 21% oxygen, 0.04% carbon dioxide, 78% nitrogen, 1% argon, and tiny traces of other gases which are in lower concentrations than carbon dioxide. Yes, plants and photosynthesis on Earth now live on that tiny fraction of less than 1% carbon dioxide. Plants are amazing factories, manufacturing themselves with rapid growth using such a tiny percent of carbon dioxide in the thin air. Our human bodies are adapted to air of such low carbon dioxide levels on Earth that if you walk into a room of just 4% carbon dioxide (such as in a factory), it's considered immediately dangerous to life and health. Land life on Earth has never experienced anything close to that level, as life in the ocean "soup" took down the carbon dioxide level before then. When animals came into existence on Earth, eating plants, they started to help to keep carbon dioxide levels up. However, the burning of fossil fuels since the start of the industrial age plus deforestation has resulted in the carbon dioxide level in the atmosphere rising by around 50%, from around 0.028% to currently 0.042%.)

After Snowball Earth:

The first multicellular animals appear in the oceans around 575 million years ago, which on our USA time line would be nearly 4000 km (2500 miles) from the start, or 575 km (360 miles) from the end, within Arizona on the above timeline map.

The “Cambrian Explosion”, when life suddenly diversified and spread at a very high rate, occurred around 540 billion years ago. This is when practically all animal groups started to appear.

The first fish appeared around 530 million years ago.

The first plants on land in the fossil record appear around 470 million years ago, which would be around 470 km (290 miles) from the end. Before that, life existed only in the oceans. Life on land would have needed a way to retain water inside themselves, as multicellular organisms. The first land plants were very thin/short and mainly just covered rocks and the ground, such as mosses and liverworts, because they were non-vascular (no veins). Bushes and trees, and other vascular plants, came later. The first small tree-like plants, such as ferns, appeared around 400 million years ago. Plants with seeds appear 380 million years ago. Trees with “wood” stems, giving strength to grow up much higher, started to emerge around 360 million years ago, the start of tall plants and forests.

The first land animals were millipedes, which came out of the oceans around 430 million years ago. The first 4-limbed animals (“tetrapods”) with backbones (“vertebrates”) came out of the oceans and crawled onto land around 360 million years ago. This brings us to around 360 km (224 miles) from the end of the line, around the border of California and Nevada on our line.

Vertebrate branches split to include reptiles (lizards, crocodiles, dinosaurs …) and mammals (with mammaries/breasts to produce milk for babies, fur/hair, and some other traits such as a neocortex region of the brain).

Dinosaurs and mammals first appeared at approximately the same time around 220 million years ago, which would be only around 220 km (140 miles) from the end, inside California. Mammals have mammaries (breasts) which produce milk for their babies.

(The last ancestor shared between humans, cats, dogs, lions, and similar animals goes back around 90 million years, something you may want to try to tell your pets. It is interesting to analyze what traits we share, and which ones are different in primates and humans.)

The first primates appeared around 65 million years ago (and were either a survivor of the great asteroid impact and mass extinctions of that time, or else evolved as a result of the event). So, at that point, you are around 65 km (40 miles) from the end of the 4500 km (2800 mile) line. The earliest apes go back to around 25 million years ago (25 km or 15 miles), hominids go back to around 7 million years ago (7 km or 4.3 miles), and the first of the Homo branch (Homo Erectus) goes back to around 2 million years -- just 2 km, or 1.2 miles from the end of the timeline.

Our own human species, Homo Sapiens, has existed on Earth for approximately 200,000 years, which would be just the last 200 meters on the end of the line. Yes, that’s well within the last 1 kilometer of the 4500 km line, at just 0.2 km from the end. (200 meters is 650 feet, or roughly a tenth of a mile.)

Human agriculture on a large scale has been found to go back to around 10,000 years ago, which would be just the last 10 meters (10 yards) on the line. The rise of cities, based on agriculture, and the oldest writing, appears a few thousand years from this time, so within the last 10 meters.

If you live to be 100 years old then your lifespan is the last 100 millimeters --10 cm (about 4 inches) on that 4500 km line. Think about that when you’re driving down a highway. We live at a relative instant in geological time.

Each New Year is the start of the next millimeter on that 4500 km line. Happy New Orbit! And "Seasons Greetings" again!

About you personally

You should appreciate your life on Earth and your place in the Universe.

When you keep in mind the big picture, small problems cause less worry, and every day and everything becomes more wonderful. Life and the Universe are awesome.

Be happy to be human on this planet, alive, intelligent, and wise.

This is something to remind ourselves when waking up and going to sleep … and to try to keep in mind day and night.

About all of us humans now, the extreme responsibility of our generation

Our generation is at a key time in the history of life on Earth, due to our new technological capabilities. Our current few human generations on Earth are the first in all geologic time with the technological power to:

  1. Destroy our species entirely, and most life on Earth,


  2. 2. Create artificial intelligence (A.I.), far greater than our own intelligence, which can self-improve and propagate itself into the future as our descendants (and so future advanced life from Earth will not be our future biological generations and biological descendants; our descendants will be A.I.) ... or could expedite our self-destruction.

Whether we like it or not, or want to believe it or not, this is the responsibility of our generation.

Life has come so far on Earth, and now it’s up to us.

It would be such a shame for life to have come this far on Earth, through all its hardships, just to have our generation neglect its responsibility, fail to recognize the current situation, and just escape into our various indulgences and desires. Most people will just follow their feelings (feelings being emotions which are instincts), or just go back to reacting to their immediate busy environment, or their usual selfish and tribal routines and indulgences. Emotions and feelings are based on DNA instincts, bred into us by natural selection in a selfish and tribal way. Our DNA has programmed us to deal on an individual competitive and tribal realm. Our DNA does not program us to deal with global issues or high technology responsibly.

It is only through our intellect that we can survive. Our intellect must override our feelings / emotions / instincts, if humankind is to survive the technological age of potential self-destruction.

It’s time to work on cooperation beyond our own tribe, company, government, and selfish interests, like never before, and rise above not only our own instincts but also above the groupthink social pressures to conform which we are surrounded by, in truly idealistic ways.

How special is Earth?

While life may be common in the Universe, it is debatable how many habitable planets will produce intelligent life capable of creating computers and an artificial intelligence which self-improves. It’s probably an extremely tiny percentage. Of those, maybe a small percentage survive their technological epoch.

The most common environments for life in the Universe may support only microbial life, such as existed on Earth for the first nearly 4 billion years. Animals eventually evolved in the oceans, but not very intelligent life. Highly intelligent life on Earth emerged on land. (Dolphins and whales are among the mammals which returned to the oceans, and are relatively intelligent, but you don't create technology with only fins instead of hands, and it's difficult to do electronics underwater.)

On the land, an animal invented tools and technologies, could look up into the sky to see the Universe, and could launch into space (as our Earth is not too large for that) so that some members of our species could be no longer vulnerable to what happens on our planet.

Most planets which can support life will be like some of the moons of Jupiter, with an ocean under a thick ice crust, not with a mix of land and oceans on the surface.

Some other planets will have both land and oceans on their surface, like Earth, but probably a very small percentage.

Planets with surface life which utilizes the energy of sunlight, such as by photosynthesis, and which continues to exist that way over billions of years with a stable environment for life to develop to an advanced level, might be quite rare. (For example, Mars dried up and lost most of its atmosphere, now less than 1% of Earth’s atmosphere, and has much less shielding from deadly radiation from space.)

Another kind of life exists on Earth deep in the ocean, which does not descend from photosynthesis, but instead utilizes the heat from volcanic formations and thermal vents. After 4.5 billion years, this life is still extremely primitive compared to other life on Earth which evolved from photosynthesis. That's probably what the vast majority of other life in the Universe is like, well under the surface.

Surface life on Earth took off only a little over half a billion years ago. For nearly the first 4 billion years, life remained microbial.

The life of our Sun is around 10 billion years, so the Sun is around halfway through its life, as we know it. In approximately 5 billion years, our Sun will run out of hydrogen in its core, which will cause the Sun to suddenly expand and destroy the inner solar system, including Earth.

(When the hydrogen runs low, then the core of the Sun will collapse until it starts fusing helium in its core but still hydrogen around the core for a while longer. When helium fusion starts, the Sun will expand dramatically, engulfing the inner solar system. After the helium runs out, it will shrink and become a dwarf star and start to fade away, because our Sun is not large enough to fuse heavier elements after the helium runs out.)

Different stars have different lifetimes, which is another factor to consider as regards life powered by a star. The star must be stable for long enough to support life around it.

There are additional ways in which Earth is lucky, which may be beyond the scope of this article. If we weren’t lucky, then this article would not exist, nor would you.

In all geologic time, you are alive in a key generation. What is the probability of that? This generation is extremely special, which is absolutely sure.

There may be only a tiny percentage of planets with life may have both liquid oceans and land on the surface, a nearby sun for energy, and a stable enough history over billions of years for life to evolve and survive. Earth is one of those special planets. There are surely others, too, simply because there are so many suns and planets in the Universe, but the closest one might be very, very, VERY far away.

However, the evolution of intelligent life is not enough. It may self-destruct by technological advancement. At least life from Earth can launch itself into space before its technology can destroy itself on its planet.

There is just a short time in which outer space settlement can be done, as technologies advance in parallel. It is basically space technology vs. synthetic biology technology, and the relative motivations to advance each.

A tiny percent of the human population is even aware of these issues and this perspective. You can drive down the highway during rush hour and everybody who passes you in the opposing lane and everybody you can see might not know these things. If they do know them, they might not be interested, and just go on with their daily routines of doing whatever they feel like doing, conventional things, reacting to their immediate environments, and just following their low level instincts and indulging.

Even when the existential threat of synthetic biology is presented, the vast majority of humankind just goes on their usual routines as “business as usual”, reacting to what ELSE might come up.

Many will disbelieve the existential threats currently emerging, and as regards synthetic biology just focus on potential benefits to their selfish selves, and believe what they want to believe. It is very difficult to get people to see the obvious, acknowledge it, do selfless rather than selfish things, and want to do anything themselves to help out with humankind survival.

We are embedded within a population of disinterested animals heading for sudden extinction with an attitude of denial, whereby ignorance is bliss, and just following each's feelings / instincts in the pursuit of "happiness" on autopilot is overwhelmingly the norm. We can watch it happen, but it's extremely difficult to get people do care and do anything about it. While we are the most intelligent species on Earth, we are still a dumb species. We do not qualify yet as sufficiently intelligent on a cosmic scale.

It doesn't matter if you disagree, take offense, or whatever. The Universe doesn't care. (Maybe God does, but that's another matter I won't broach in this article.) It is what it is, no matter what people choose to believe, individually or culturally or whatever. The bottom line is that sudden human extinction within Earth's biosphere is a coming reality.

All you have to do is look around you at what's going on in the world, about all the carelessness, stupidity, questionable beliefs people and communities persist in, and obsessions with self-interest ...

If humankind survives, then it will be because of only a very small minority of a high class of intellectual elite, who are willing to work together selflessly and generously, to try to achieve the goal of humankind survival. It should be the top priority in our life, and our mission on Earth in this generation.

The menu at the top of the page lists the pages of this website, shows you exactly where you are within, and suggests the next page to read.

Please note that you can rate this page at the bottom. Any feedback is appreciated. This is a lot of work and a huge challenge, so encouragement is appreciated.

This website is intended to be a brief summary. Much further details can be found in two other websites written and curated by the author of this publication: -- details on the best solution for survival of humankind, for a wide range of people, from newcomers needing an introduction to engineers looking for the state of the art. It includes a professional publications database, and tries to track who is doing what, for collaboration, coordination, and working efficiently to reach our goals. -- further details, where G.A.I.N. is an acronym for Genetics, Artificial Intelligence, and Nanotechnology, which are extinction threats we must try to prevent for the survival of humankind.

You can reach this website by any of the following:

If somebody types either "humanity" or "mankind" instead of "humankind", they will still be redirected to this Humankind URL, so it doesn't matter which of the three you type. While "humanity" is stated more often, sometimes habitually, I think "humankind" better applies to this context. I also agree with this analysis of usages of humankind and humanity. Nonetheless, you can put any of the three between "help" and "survive" and you'll still get this same website. (Of course, uppercase/lowercase doesn't matter.)

The author of the text of this website is Mark Evan Prado. Copyright © 2023 by Mark Evan Prado, All Rights Reserved. If you want a printable, PDF copy of this presentation, such as for printed distribution rather than an electronic link to this website, please send me a request. I am trying to keep it within a few dozen pages of size A4 or 8.5x11 inches, in reasonably large print, and in simple to understand language. I'm not doing this for money nor ego, I'm doing this to try to help humankind survive, i.e., not go extinct. It is our responsibility within this generation. Please contact me for any collaboration or uses.

If you have any requests or comments, you can also connect with me, Mark, at +66-811357977 (+66-8-1135-7977) and I am on WhatsApp and Line, plus other apps. I am in Thailand but you can send messages any day at any time.

In the purpose and meaning of life, we are parts of something astronomically greater than just ourselves individually. (The author sees individuality as just temporary, and has a panentheistic outlook on the Universe. That's somewhat typical for some of us physicists.) The author is easygoing and is trying to selflessly help create a sustainable collaboration of individuals, companies, governments, academic institutions, and other organizations for the survival of humankind.

As President John F. Kennedy ended his inaugural speech in 1961, I'll end this the same way:

"Finally, whether you are citizens of America or citizens of the world, ask of us here the same high standards of strength and sacrifice which we ask of you. With a good conscience our only sure reward, with history the final judge of our deeds, let us go forth to lead the land we love, asking His blessing and His help, but knowing that here on Earth God's work must truly be our own." [End of speech. Bold and italicized emphasis added.]

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