September 7, 2023
Just before I was born the Universe was thought to be just the Milky Way. Astronomy has come a long way, but there are still many mysteries out there. Perhaps the biggest is dark matter. Scientists believe most of the Universe consists of mostly dark matter and we know very little about it. Dark matter does not reflect light or interact with photons as other atoms do. It only reveals itself because it does generate gravity and affects galaxies.
At the time of this essay it is thought the Universe is about 13.7 billion years old. The Big Bang Theory is still the leading theory on how the Universe began. When I was in grade school the steady state theory was considered most likely to be true. That theory was that the Universe was static and that it would remain the same forever.
The James Webb telescope has been operating for about 19 months and has given us new data that is causing trouble with current views of our Universe. The Universe may be older than we thought as distant stars and galaxies are seen to exist way too early. Some suspect that the Big Bang Theory is not true. How this will be resolved I do not know.
Our modern eyes looking at the Cosmos are so new. For most of my life astronomers used film to record their data. Film was limited in both detail and wavelength sensitivity. The use of digital photography for space research is less than 40 years old and that has gone through numerous improvements in detail and sensitivity. During my grandchildren’s lifetime they will see continents on exoplanets and be able to see signs of life.
One subject I find fascinating is the theories about how we may be part of a multiverse. There are many types of multiverses that have been proposed. None have any data supporting their existence, but it is fascinating to think copies of us may exist somewhere in time and space.
I hope I live long enough to see humankind set up settlements on the Moon and Mars. Stephen Hawking was correct in seeing the need for humankind to become a multi-planet species and eventually a multi-system species. One big question is whether we can live in space or planets very different than Earth. I feel that until we can create artificial gravity by rotation long trips in space will be very unhealthy. The issue of radiation also needs to be addressed as far as travel in space.
Science fiction literature has dreamed about faster than light travel, but based on today’s physics it is impossible. As impossible as time travel.
While I do think there is life on other planets, I also believe it is so rare that the distance between most intelligent life is beyond their reach to visit each other. Not only visit in person, but to communicate by radio communication. If any life is found on Mars or some of the distant moons of our solar system I think it is related biologically to us. Time is very long and I can see that over time a planet with life can send seeds (meteorites) of life to other bodies within our solar system. The Earth’s surface is so active because of water, air and life we do not have good records of mega-meteorites hitting the surface and blasting off large chunks off into space. As we have found meteorites from Mars at the South Pole there are probably pieces of Earth that have reached other solar system bodies as well.
As to intelligent life communicating with us it is a very long shot. The Fermi Paradox posits that the Universe has existed long enough for there to be life all over the Cosmos. Human civilization is only 10,000 years old and we really did not start advanced technology until after 1500 A.D. Fermi thought there has been more than enough time for other worlds to have intelligent beings. There should be other intelligent civilizations that have been exploring space for millions of years ahead of us. There should be mega-structures such as Dyson Spheres or giant O’Neill Cylinders orbiting stars within our Milky Way. And yet, we have not seen any other signs of intelligent life in either large structures or electromagnetic signals.
Perhaps in my Grandchildren’s lifetime when we will have orbital telescopes that cover square kilometers instead of square meters, we will find evidence of advanced civilizations. As of now, it they exist they must be extremely rare. If there are only two or three advanced civilizations in a galaxy they could be thousands of light years apart. As pointed out by other scientists we may be the first life that has built technology to explore space.
As Carl Sagan points out space is very very large. There is a real limit as to how far we can explore by space travel because space is so incredibly large. Because of Hubble’s discovery that the Universe is expanding there are galaxies that are beyond of Cosmological horizon and speeding away from us faster than light. We see no light or information from those galaxies beyond our Cosmological horizon.
There are only about 500 million years left where Earth can sustain life. The sun is increasing in temperature and unless we can learn to move planets or control stars we will have to abandon our home planet. If we can succeed in not destroying humankind or be destroyed by our hostile Universe we could settle the entire Milky Way, but that is a very optimistic thought.
I wish I could live long enough to know the true story of life. How it came into being? How far it can advance and what wonders will it discover about our Universe?
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