Tuesday, February 25, 2020

No Encounters of the First, Second or Third Kind

Extraterrestrials visiting Earth.

The idea conjures visions of strange beings but not so strange that we don't recognize them. ET, the aliens from Close Encounters, Klaatu, Marvin the Martian and countless others have graced our TV screens, theater marquees and the pages of comic books. We've seen humanoids, insect-like creatures, intelligent floating squid creatures and even rocks.

Just how likely is it that we've had visitors from distant worlds?

Let's break it down.

1) Technology and Energy
The technology to get a spacecraft of appreciable size (i.e. capable of supporting some kind of human sized organism inside) is doable. Humans have been doing it for nearly 60 years. However, none of those spacecraft have been built to sustain life for the amount of time it would take to fly among the stars.

"What about the International Space Station?" I hear you cry.

The ISS is quite a feat of engineering but it's not self-sustaining. If not for missions that take supplies and remove waste (old wrappers from food, soiled clothing and... other stuff), it would soon become unlivable.

Could a sufficiently advanced civilization build such a craft? Possibly.

But then there's the question of energy.

In order to hurl something the size of the ISS from here to the nearest star, Proxima Centauri, in a reasonable amount of time, say 25 years, would take about 9 times the amount of energy that the entire United States generated in 2009. The power plant that would generate this energy would be enormous... and added weight means added energy to move it.

There are many fanciful, imagined means of propelling a spacecraft and maybe some of these exist in the labs of other civilizations. But, like it or not, they are still subject to the laws of physics and engineering.

Incidentally, as you get closer and closer to the speed of light, all forms of electromagnetic energy blue shift to shorter and shorter wavelengths. At sufficiently close to the speed of light, visible light can shift to become x-rays and gamma rays.

Add in more weight to shield the crew from being fried by those.

Let's put that aside for now to look at other issues.

2) Motivation
Why would they come here? What is here (besides us) that isn't more readily available elsewhere in the galaxy?

Water is far easier to come by in the outer solar system. There are entire worlds of ice and other volatiles and you don't have to try to drag them from the pit of Earth's gravity well.

The same goes for any minerals, metals or rare earth materials. Asteroids are far easier to mine for that stuff.

Are they curious about our civilizations?

For that, they need nothing more technologically advanced than the television. Even before the outbreak of World War 2, we were sending radio and television broadcasts out to the stars in an ever expanding sphere of radio noise. It's traveling outward at the speed of light and cannot be recalled.

They can learn our language, our writing and number systems watching a primer that's been transmitted for more than 50 years: Sesame Street.

If they send craft, they wouldn't even have to enter our atmosphere to collect useful information. Our own satellites do that.

Would they come to breed with us to make a human/alien hybrid?

Unlikely. You'd have better luck crossing a human with a rhododendron. At least those two have more genes in common that you would with an alien.

This is what makes it equally unlikely they want us or our livestock for food. We'd probably taste pretty nasty.

3) Awareness
How do they even know that we're here?

As mentioned before, we've been broadcasting radio noise for quite some time, about 100 years or so. That means any civilization that even had the slightest clue that we're here would have to be within 100 light years.

We know this region of space pretty well and we haven't detected even a peep of another civilization.

When we search for extraterrestrial signals, we search for radio signals because that's what we broadcast. Aliens detecting our radio signals would search for them because that's what they use. So we should have heard them by now. There have been a few interesting traces of signals but nothing yet that would indicate they've "got their ears on."

Any civilization outside that 100 light year radius wouldn't have any way to detect that we're here.

4) Technology We Haven't Discovered
It's true that we haven't reached the pinnacle of what we can achieve technologically. But that technology is always going to be limited by physics. There are no magic shortcuts around it, either.

Science fiction has come up with some wonderful imaginative devices but that's what they are and that's what they'll remain: fiction.

Faster than light technology? Transporters? Great for getting people around in SF movies but they go beyond impractical to the impossible.

And that brings us to our final point.

5) Practicality
It's simply not practical nor is it necessary for an alien civilization to visit Earth.

Better to stay at home and learn about us from our radio and television signals.

Is there other life in the universe?

The simple answer is we don't know.

It's not a satisfying answer but it's the best one. It leaves room for possibilities.

Nobody wants there to be more than I do. And, yes, I'd love to hear that first signal. I'd even like to be proven wrong about aliens visiting this planet.

But I live in the real world and expect real evidence.

Shapeless blips from wing cameras?

Sorry, but that could be anything.

We don't know what they are but that's no reason to declare that it must be extraterrestrial.

You simply don't explain the unexplained with the inexplicable or unlikely.

Admitting that we don't know is the first step.

Then we search to find out what it really is.