The Old Astronomer Continues His Story… Until He Dies

At Home In The Universe

Part 8: “The Sun and the Earth formed about four and a half billion years ago, when I was 37 ‘Milky Way years’ old. A solar system forms relatively quickly and ours probably took only about 100 million years.

The Sun and the planets formed from a cloud of sparse gas in the Milky Way, which condensed down and coalesced. After this happened, the Earth was very hot. It was a completely molten ball of rock and had melted so thoroughly  that its consistency was similar to water. Certainly, no life could have existed on the very young Earth.

Soon, however, the conditions on Earth became suitable for life. For our carbon-based type of life to develop, a planet needs to have organic matter, liquid water, a source of energy and appropriate temperatures. The Earth had all of these fairly early in its history. Scientists aren’t sure when life first appeared on Earth, but some evidence dates the earliest life at three and a half billion years ago, when I was 47 ‘Milky Way year’s old.

Evidence suggests that life appeared almost immediately once the necessary conditions were satisfied on the young Earth, but the first inhabitants of the new planet showed no strong predisposition for evolution to more advanced life forms. More than two billion years passed before primitive, single celled microbial organisms advanced to become multicellular life! Once it did, however, advanced life took rapid hold. This period of rapid development in the complexity of life is called the Cambrian Radiation or Cambrian Explosion. The Cambrian Explosion occurred 3 years ago, when I was 56 ‘Milky Way years’ old.

Cambrian explosion

Since the Cambrian Explosion things have become very interesting on Earth. I was barely a year older by the time these primitive multicellular creatures had developed to become the dinosaurs, which were unimaginably more complex and advanced by comparison.

Cambrian radiation

Now we come into recent times, as the appearance of the dinosaurs occurred only twelve months before the Now in my life. The dinosaurs had a short stay on Earth. They disappeared 65 million years ago on your clock or four months ago by my clock. This gave mammals the chance to rise to dominance.

The first humans appeared on Earth only eight hours ago, at least by that clock of mine. Civilization accounts for only a small fraction of my time. The first system of writing and the first evidence of civilization dates to only 6,000 years ago, or fifteen minutes ago by my clock.

All of culture and all of written history could fit into my coffee break! The first scientists, who considered observation and experimentation to give the last word on the nature of the universe, lived only about four hundred years ago, or one minute ago on my cosmic clock.

Big Bang explosion

Today I am 59 ‘Milky Way years’ old and just for a split second, we are contemporaries.

The Milky Way will continue on its normal course, a course which happens to be headed straight for a collision with the nearest neighboring galaxy, the Andromeda Galaxy, in about 12 ‘Milky Way years’, when I will be 71. This is unlikely to be the disaster for the Earth it might appear to be – a collision between any stars during a galactic merger is actually extremely improbable. The Solar System will simply take up residence in the new galaxy created in the aftermath of the collision.

Andromeda Galaxy

Five billion years from now, the Sun will have used up all its fuel and will die. At this point, about 20 billion years after the Big Bang, I will be 80 years old and I will die also, together with the Sun, but much too early to witness the universe dying. The Earth will no longer be able to support life after the Sun dies and the Solar System will become rather desolate.

The universe as a whole will continue long, long after the death of both the Sun and me, but it too will slowly die, in a far, far away future.”


Thanks to Wikibooks, General Astronomy, Short History of the Universe, and special thanks to Richard Fortey for his book ‘Life: An Unauthorized Biography’, to Sidney Liebes for ‘A Walk Through Time: From Stardust to Us’ and, last but not least, to Bill Bryson for his ‘A Short History of Nearly Everything’

All articles of this series can be found in: At Home in the Universe

ShantiShanti is a regular contributor to Osho News

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