Hiding an entire planet might seem like a magic trick instead of a scientific achievement, but a recent Tech Insider article explores a new way to cloak the planet in the event of an alien invasion.
According to David Kipping, "Recently, my graduate student Alex Teachey and I published a paper that proposes a way to cloak planets, as well as a way to broadcast a civilization’s existence. Even if we’re not manipulating our own signal in this way, it doesn’t mean other planets out there aren’t. It’s possible what we see as we scan the universe for other habitable planets has been engineered to disguise or highlight the existence of other civilizations.
Humanity’s most successful technique for detecting other planets is the transit method. A transit occurs when a planet appears to pass in front of its parent sun, blocking out some of its starlight for a few hours. So if we have our telescopes trained at one part of the universe and a star seems to fade out for part of a day, that tells us that a planet has temporarily come between us as it goes about its orbit.
It turns out that hiding planets from the transit method would be surprisingly easy, so easy that we earthlings could do it right now, if we chose. Since transits appear as a brightness decrease of a distant star, our hypothetical cloak simply produces the opposite brightness increase."