In addition, we could search for a swarm of satellites or megastructures that block a significant fraction of the light from distant stars, as envisioned by Freeman Dyson. However, such gigantic megastructures may be rare or non-existent as they face major engineering challenges.
If we recover anything artificial through our archaeological dig into space, the natural question to ask is: Are we the smartest kids on the block? If the answer is no, we could learn a lot from our findings and perhaps shortcut our own evolution by thousands, millions, or maybe even billions of years.
It is difficult to avoid the thought that our intelligence bar would not be difficult to surpass. We fight among ourselves in “lose-lose” situations, we favor short-term manipulations over long-term benefits, and we have been carelessly broadcasting our existence to the entire Milky Way galaxy in radio waves for over a century without worrying about any predators in outer space. One might even wonder whether we have simply been ignored by predators because we appear so incompetent. But as far as space archaeology is concerned, the key challenge to improving our awareness of other civilizations is whether we are intelligent enough to adequately interpret their products.
Our discovery of a piece of advanced technological equipment developed by an extraterrestrial intelligence may resemble an imaginary encounter of an ancient cave people with a modern cell phone. At first, they would interpret the phone as a shiny rock without realizing that it is a communication device.
One fact is clear: If we assign a zero probability for finding evidence for artificial objects, as some scientists did in the case of ‘Oumuamua, then we will indeed never find any evidence for aliens.
How can our civilization mature? The same way kids do, by leaving home, meeting others, and comparing notes with them. In other words, we can develop a balanced perspective on our current technological accomplishments by searching for relics of extraterrestrial intelligence. Since our own technological development accelerates exponentially, it is difficult to imagine the face of a much more advanced technology crafted by a civilization that had lived for a cosmic time-scale.