Origin of Intelligent Life
Here's a question
- Are we alone in the universe?
Currently there is no empirical evidence to support the existence of life on other planets. However, the amount of data we've gathered on the topic is so minimal, it doesn't merit even a scientific inclination for or against the existence of extraterrestrial life. Thus, as far as life's intriguing question go (pun intended), this is surely among the greatest! I've certainly speculated for a-many late hour, in various states of mind. I've even had several overscrupulous conversations on the matter with a variety of academics. From these conversations, I've gleaned there is a general consensus that we are not alone in the universe. However, I tend to think we are alone, here on Earth, and the universe. To clarify: Do I think life exists on other planets? Maybe. Do I think there are creatures with human-like (similar or greater) intelligence? No. I think we are the most intelligent organism in the universe. It's purely speculation...
The age of the universe, aka the length of time elapsed since the Big Bang, is currently estimated to be 13.75 ± 0.11 billion years. That's Billion with a B as in 13,000,000,000 years. Earth is around 4.54 billion years old. Here's the timeline of our 4.54 billion year old Earth:
3.5 billion years of simple cells (prokaryotes), 3 billion years of photosynthesis, 2 billion years of complex cells (eukaryotes), 1 billion years of multicellular life, 600 million years of simple animals, 570 million years of arthropods 550 million years of complex animals, 500 million years of fish and proto-amphibians, 475 million years of land plants, 400 million years of insects and seeds, 360 million years of amphibians, 300 million years of reptiles, 200 million years of mammals, 150 million years of birds, 130 million years of flowers, 65 million years since the non-avian dinosaurs died out, 2.5 million years since the appearance of the genus Homo, 200,000 years of anatomically modern humans
Earth became a stable planet circa 9 billion years after the big bang. Abiogenesis (the generation of biological life from inorganic matter) on Earth is estimated to have occurred 1 billion years after the planet stabelized (4.5 billion years ago). Another 1.5 billion years of evolution resulted in eukaryotes, then another 1 billion years elapsed before the first multicellular organisms arose (1 billion years ago). Over the last billion years, there has been a huge amount of evolutionary diversication on Earth; mammals evolved around 200 million years ago. A most recent addition to Earth's biodiversity is the species Homo Sapien, which has existed for 200,000 years. That's not very long. To put it another way, if the length of time life has existed on Earth was divided into 17,500 equal eras, humans have existed for only the very last of these eras.
Let's talk about space travel and interplanetary communication.