The Scale Used To Classify Alien Civilizations Explained
According to The New Yorker, it's quite possible that aliens have visited us, but if they did it's likely they arrived so long ago that they left no written records or other archeological evidence. For now, though, the scientific community is proceeding as if aliens haven't been here but may yet show up someday.
If, or when, intelligent extraterrestrials do visit us, it would have significant scientific implications. For one thing, the alien civilization would somehow have managed to overcome — or use to their advantage — the fundamental laws of physics that govern space travel. This is because currently, traveling between galaxies would take thousands of years (via Universe Today). Simply put, if they get here at all, then they're way ahead of us technologically (via The New Yorker).
Back in 1964, a Soviet astronomer came up with a scale that assesses just how far advanced an alien civilization could be.
How the Kardashev Scale works
Back in the 1960s, a Soviet astronomer named Nikolai Kardashev published a scientific paper in which he categorizes the amount of energy an alien civilization is able to harness, as Space.com explains.
A Type I civilization produces and consumes energy in much the way Earthlings do — or did, but more on that later; a Type II civilization has learned to harness the power of its own sun, and a Type III civilization has learned to harness all of the power of all of its stars in its own galaxy. According to Futurism, scientists have added two more categories: A Type IV alien civilization can harness the energy of the entire universe, and a Type V civilization can harness the energy of all universes across all timelines.
So where are we in all of this? That depends on whom you ask. Since most of our energy comes from fossil fuels, we're not even Type I yet and by some estimates, we barely qualify as Type 0.7 (via Space.com). Although it does bear noting that in the nearly 60 years since Kardashev published his paper, we've started using more solar energy, for whatever it's worth.