Of course we all know that aliens want to take over Earth. It’s in all the movies. And after they take over, they could do whatever they want to us puny, weak Earthlings. Enslavement? Yup. Forced breeding programs? Sure. Lay eggs in our bellies and consume our guts for their first meal? Why not.
But here at Universe Today, we’re science-minded types. We love the science fiction, but don’t take it too seriously. But someone we do take seriously when he has something to tell us is Stephen Hawking. And when he warned us that aliens might want to conquer and colonize us, it lent gravity to the whole discussion around contact with aliens. Should we reach out to alien civilizations? Will we be safe if they find us? Or should we try to conceal our presence?
If we choose concealment, then a new paper from two astronomers at New York’s Columbia University have good news for humanity. The authors of the paper, Professor David Kipping and graduate student Alex Teachey, say that lasers could be used to hide Earth from alien prying eyes.
At the heart of this whole idea are transits. When a planet passes in between its star and a distant observer, the star’s light is dimmed, and that’s called a transit. This is how the Kepler spacecraft detects exo-planets, and it’s been remarkably successful. If alien species are using the same method, which makes sense, then Earth would be easily detectable in the Sun’s habitable zone.
According to Kipping and Teachey, lasers could be used to mask this effect. A 30 MW laser would be enough to counter the dimming effect of Earth’s transit in front of the Sun. And it would only need to be turned on for 10 hours, once every year, since that’s how long Earth’s transit takes.
But that would only take care of the dimming effect in visible light. To counter-act the transit dimming across the whole electromagnetic spectrum would require much more energy: a 250 MW cloak of lasers tuned all across the spectrum. But there might be a middle way.
According to an interview with the paper’s authors in Science Daily, it might take only 160 MW of lasers to mask biological signatures in the atmosphere. Any prying alien eyes would not notice that life had ever come into being on Earth.
Should we decide that we do indeed want to be colonized, or forced to take part in breeding programs, or be enslaved, then the same system of lasers could be used to amplify the transit effect. This would make it easier, rather than harder, for aliens to detect us. In fact, according to the authors, these lasers could even be used to communicate with aliens, by transmitting information.
Of course, there’s one other element to all this. For this to work, we have to know where to aim the lasers, which means we have to know where the alien civilization is. And if we’re worried about them coming to get us, they will have more advanced technology than us. And if they have more advanced technology than us, they will for sure already have laser cloaking like the type talked about here.
So who’ll be the first to blink, and turn off their laser cloaking and allow detection?
You first, aliens.
I found this to be a generally poor article. I did not appreciate the sarcastic cynicism at the beginning. Saying you are “science-minded types” and “don’t believe in science fiction” is contradictory.
To me, true science is testing hypotheses fairly and objectively, without automatically ruling out possibilities simply because they don’t fit your mindset.
And I will say that although Dr. Hawking is well-respected in the world of astrophysics, his few comments on extraterrestrial life are overly simplistic, and behind the times. Saying that extraterrestrials might want to conquer us for Earth’s resources completely ignores the fact that a civilization that has mastered interstellar travel probably has access to the resources of countless planets much closer to home.
Lastly, I disagree with the assertion that the laser masking would only need to be done once per year when Earth transits. My response is- based on whose perspective? There is no up or down in outer space, so depending on the orientation of other solar systems, Earth might have to be masked 24/7/365.
Overall, a very poor article laced with unnecessary cynicism.
The once a year notion is based on us detecting another civilization first.
Once we know where they are, to hide from them we point our laser at their home star system during the 10 hours we would be transiting as observed from their star system.
Our planet will be visible to the alien species long after we detected them. Let’s say they are on a planet 1,000 ly away. If we detect them, they will be able to detect us for about 1,000 years. If all of a sudden they lose sight of our planet, that would prove intelligent life if we can’t have an alternate theory as to what happened to our planet?
We would have to stage the fake death of our planet. And that in and of itself could have some serious consequences.
Probably the better solution is take that 1,000 years and build some form of planetary defense. So if that 1,000 ly distance is not big enough to keep them from coming here, we can at least prevent our own extinction.
Damn, you’re mean… Did that make you feel better?
Any advanced civilization we should be concealed from that is unaware of us as a candidate of interest may be highly attracted to us with either our monochromatic beam or an unlikely near perfect spectral distribution beam. This ruse will not hide us from the other means of detection. Ironically, this could be their first strong evidence to come take a look, hopefully not to wipe us out, though given such a consequence it’s something to consider.
[corn] If they are looking for us orbiting a yellow star, however, then we are safe. This may be the better ruse. [/corn]
Something to think about. If we ever had the technology to travel to another star even at sub-light speeds, It would be a generational ship. That ship would have to have a plan to live on a planet to at least prepare for the return journey.
What happens if that planet had early industrial life once we got there? Much like Earth today? The ship needs a place to resupply, upgrade any part because of advances made during the trip. The act of slowing down might itself damage the planet in some way. We could carry germs that would be lethal to the local inhabitants. They could have lethal germs that could kill us. So we would blindly kill that germ just to find it’s vital to the ecosystem. Any way you slice it, we would be extremely dangerous to the indigenous species. If we don’t kill them, they might try to kill us just to prevent their own accidental extinction.
So there you go. Two peaceful species just trying to survive. No evil intent what so ever. Now if they are truly evil or this isn’t their first visit to a planet or visitation from another planet, they’ll probably fire first while our generation ship is still slowing down. We might have to intentionally kill the indigenous species before we even can talk to them. Telekinetic energy would actually make that simple. Let sale several several ton aerodynamic weights at a few 1,000kps velocity at the planet before breaking and that planet would be as good as dead by the time we arrive.
So the table is turned and we become the beast from outer space.
good thing Earth’s light
dims only once a year,
while the remainder of days
we can go blindly without fear.
for the hunt of Earth’s shadow
by the aliens that are near
will science our light’s refractions
filtered through Earth’s atmosphere.