A.S. — Kudos on another informative and interesting article. A couple of points:
1) First, a point of clarification. My understanding is that the Milky Way galaxy is now said to be closer to 200,000 light years across. Any thoughts? https://www.nbcnews.com/mach/science/milky-way-galaxy-may-be-much-bigger-we-thought-ncna876966
2) Yes, there’s most likely life in the Universe, both on the microbial level and advanced intelligent level. There might even be more than one Universe as we know it, at least theoretically per the Multiverse.
Although I have no proof of ETs, consider that complex mathematics, astrophysics and common sense lead to the conclusion that we are not alone. There are hundreds of billions of galaxies in the known universe, each with hundreds of billions of stars, and some stars with earth-like rocky planets orbiting their suns in the GoldiLocks Zone.
Moreover, scientists keep discovering that the known Universe is even more vast than once thought, constantly expanding at exponential rates per the Hubble Constant and Cosmic Inflation. And that’s just the known Universe, what space scientists are able to observe. We don’t know how much more expansive the Universe is beyond our Cosmic Horizon.
Let’s recall that humans are an arrogant species. Copernicus once claimed that Earth was the center of the Universe, for example. Moreover, scientists once deemed black holes laughable. Einstein and Hawking proved otherwise. Now we know that supermassive black holes fuel every observable galaxy. Thus to put our place in space and time in the appropriate perspective, consider this:
“Scale the Earth’s billions of years of life to a 24-hour day, and human civilization represents about 1/5 of a second,” at least according to one calculation I recently read. Therefore, modernity is likely a nanosecond in scale. Now how much life can primitive earthlings find in the infinite Universe in one nanosecond?
It’s more likely they will find us before we find them — assuming this hasn’t already occurred without our knowledge.