A ripple distorted the virtual air, then solidified into Dr. Xanoplatu – an alien anthropologist, galactic historian, and simulation time traveler materialized on the podium stage, embodying the ancient form of his ancestors. His avatar appeared as a large green praying-mantis-like creature with multifaceted black eyes. His hands, if you could call them that consisted of eight highly manipulative digits spaced at various positions on each arm.

He was speaking, or more precisely communicating, from inside an auditorium of a virtualized spherical space station rendered as a metaverse space-time virtuality.

This computational virtual reality was running upon cultivated hybrid von Neumann-quantum computers. The power source was the local M dwarf star system. The “computer farm” was grown inside an orbiting Dyson Swarm mega-structure of the main sequence star. The good doctor was a member species of an extremely advanced Type II civilization capable of technological magic.

Present in the same auditorium space was an impossible assortment of alien life requiring diverse support environs: different atmospheric gases, liquids, varying gravity, temperatures, light, and radiation levels. Each individual’s “brain” or cognitive structures were simulated at appropriate thought speeds, translated across multiple communication mediums, and clarified through a common conceptual symbolic language. Living computers masterfully manifested each individual present down to actual quantum thought levels; simulated yes, but no less “real”.

Species representative from many civilizations were present in this sped- up-or-slowed-down virtual time frame. Some had just recently evolved to the necessary prerequisite levels to be able to attend.

Dr. Xanoplatu looked out across the audience for just a moment, and then launched into the presentation with no introduction, which was customary for his insectoid species.

Galactic civilizations take time to form as individual alien civilizations rise and fall. Some star systems, although rare, foster the evolution of more than one intelligent species throughout their stellar evolution. The technology of alien species varies greatly. However, most civilizations tend to advance with invention of language, use of tools, modifications to environment, agriculture, architecture, industry, computers, robotics, rockets, the creation of artificial intelligence, and intelligence amplification through self-directed genetic modification, nanoconstructors, and so forth.

The inevitable consequences are familiar: overpopulation, resource depletion, environmental degradation, mass extinctions—all preceding space colonization and ultimately culminating in devastating space warfare.

Dr. Xanoplatu’s clicking language was seamlessly translated for each of the different species attending. The audience was an attentive assortment of beings ranging from atmospheric whales, dinosaurs, crabs, turtles, liquid based octopi, slimy bacterial hive minds, insectoids, hominids, and every variety of completely synthetic AI-robotic being, in addition to many intelligent plants, and virus-like colonies safely and virtually isolated. Some of the hybrid cybernetic alien beings had capable nanomachines swarming throughout their circulatory systems.

As the doctor continued giving his lecture, “images” displayed into each mind of a glorious rotating 3D Milky Way bar spiral galaxy in formation. After about 5.8 billion years from the big bang, when heavier elements from exploding supernovae dispersed, the galaxy began showing data markers for pre-spaceflight intelligent life. A time bar scale indicated the passage of millions, then billions of years ticking away as the galaxy evolved and rotated. Most of the markers representing alien civilizations began to appear, scattered throughout the galaxy. They briefly pulsed, and then sadly dimmed and vanished, indicating they had become extinct.

Near-type I civilized beings usually have intra-solar travel between planets, moons, asteroids, constructed space habitats. Some may even attempt laser projected solarsail interstellar travel to nearby stars.

Images of spacecraft of all types and shapes were shown, space habitats and colonies, followed by space weaponry. Violent images of space warfare soon followed. These images changed to those of polluted radioactive dead worlds, and finally the bones or shells of strange looking aliens.

Unease spread through the audience; there were murmurs and a definite roar from one of the dinosaur species. The doctor paused for a moment for affect, taking a sip from an archaic but refreshing water bulb which had miraculously appeared hanging around his neck.

Unfortunately, as you are all aware, this time is a very dangerous one for a young species. Many civilizations become unstable, self-destructing under the pressures of the constantly accelerating technological progress, most times resulting in their extinction, or if they’re lucky, very long setbacks. We refer to this as the Great Filter resulting in a Fermi Paradox —“Where are all the aliens?”

Dr. Xanoplatu indicated the presentation part was over, and said he would now entertain questions. The first question was from the dinosaur species from the Procyon A system. He was larger than most of the others, except for the atmospheric whale. “Are there other factors inhibiting the formation of galactic civilizations?”

Dr. Xanoplatu responded, “Yes, imagine a pond, a very big pond, one the size of the galaxy. Now throw a pebble into that pond, and you will notice waves forming, moving outwards from where the pebble impacted the water; much like communications from evolved civilizations but traveling at the speed of light. It would still take a while for the waves to travel to the shores of the pond, the edges of our galaxy analogy, approximately 100,000-200,000 years. Now, suppose you threw a hundred pebbles into the pond all at random times simulating the evolution of separate and independent intelligent life with the necessary communication technology.”

“The waves would eventually cross each other, however that would require that a civilization survive long enough for another to evolve, respond, and communicate. If say, one of the aliens tossed pebbles into the pond yesterday, or maybe even a million years ago, or millions from now, and you tossed yours in today, those waves would never really coincide in time to cross one another. Communications would then be unable to occur, because of the extinction time rates of civilizations. Hence, again you get the Fermi Paradox. Timing and civilization longevity; the formulation of a common galactic empire requires that multiple long surviving alien civilizations need to exist concurrently to achieve a lasting galactic interchange”, the doctor had answered the dinosaur.

“Our galaxy is roughly 13.6 billion years old. Trace archaeological evidence suggests the start of a galactic level civilization has been tried and failed within the last 3 billion years. We originally felt a properly civilized adolescent alien species should be able to stabilize themselves, without our interference or intervention. This is sometimes referred to as the prime directive”, continued Dr. Xanoplatu.

“However, we eventually decided to intervene.” Dr. Xanoplatu thought for a moment before continuing. “It did not always meet with positive success, the designated species self-destructed even more quickly than the original time path predicted, sometimes taking our own with them. Our analysis is inconclusive as to exactly why. No, we must let events take their natural course. It is safer to only directly intervene after the extinction singularity has occurred, then salvage what we can.”

A snake-like creature from Gliese 876 hissed, "What about simply alerting them to our existence? Broadcasting a signal – a survival guide, perhaps? Let them evolve or perish.”

“We have considered this, but our simulation analysis shows we could actually cause more harm than good. So we are evaluating each case individually”, concluded the doctor.

“I want to bring your attention to an interesting case coming up with an extinct hominid species that ironically calls itself Homo Sapiens. That I will report on in our next scheduled meeting.” The good doctor smiled, that is if you could interpret such emotions from his kind.

The lecture was concluded, and all of the attending derezzed along with the alien doctor. The auditorium vanished into nothingness.