Aliens exist, but you shouldn’t care

Do you believe in aliens?

This is a really vague question. If a “believer” asks you, they want you to say “no” so they can follow up with “how can you believe we’re the only life in the universe?!11one”. But of course – that wasn’t what the question was. The question really means “do you believe we are being visited by aliens?”

I maintain that the same logic that makes alien life so overwhelmingly likely is the same logic that makes me thoroughly disbelieve in alien visitors. In short, aliens DO exist – but you shouldn’t give the matter a second thought.

Why do I believe that aliens exist but that we are most definitely not being visited? It’s quite simple and brief to be honest:

Evolution: if you understand it in any reasonable detail, you’ll appreciate that it’s not luck-based at all. Given the right conditions, and time – evolution is bound to happen. Of course, there are no guarantees over what form that life will take.

Probability: It doesn’t matter if earth-type worlds are rare or common in the universe. Earth is certainly unique of all the planets we’ve charted so far and the solar systems we’ve scanned to date. I think it’s fair to presume that earth-type worlds are rare – but however rare you want to make them you have to appreciate the vastness of the universe. It is a statistical certainty that somewhere out there, amidst the quadrillions upon quadrillions of stars, that an earth-type planet orbits a star like our own. (To be honest, quite a variety of star-to-planet distances/compositions would probably be acceptable.)

So vast is the universe it would actually be a statistical impossibility to not have any other life out there! And if you have life, and time, and enough planets – at least one of them should produce intelligent life – perhaps even rational.

But, this is where the alien fun ends. Remember how vast the universe is. In order for us to make contact with alien life, you not only need another species to be alive, be intelligent, develop space-travel, but do so within observable range of the earth.

Light travels at 186,000 miles per second. Try to appreciate just how quick that is. It would still take 100,000 years travelling at that speed to cross our galaxy. Beyond that, at the same speed, the next closest galaxy is 2,540,000 years off. In fact, even the closest star to us would take over 4 years to reach at this speed.

Humans have only been sending out EM transmissions into space for a century. The very earliest transmissions which are nowhere near as powerful as those we send now are only 100 light years away. That’s one 1/1000th the diameter of the galaxy. In order for aliens to even be aware of our existence they’d have to be within 100 light years of earth. As we know, it’s an inconceivably-gigantic universe, and the odds of that life out there being within such a ridiculously tiny radius of earth don’t bear thinking about.

But the real killer, and for me the totally unassailable argument against alien contact (let alone visitation) is time: the universe in its current state of existence is about 15 billion years old. The earth is over 4 billion years old. Life has only been on earth for a few million years. Humans have only been on earth for a couple of hundred thousand. We have only been using electricity for just over a century. We’ve been sending out EM waves for a shorter time than that. We only achieved space-flight 50 years ago. We have only been actively looking for other worlds by scanning a tiny fraction of the heavens for a few decades. Now, even if another intelligent space-faring species actively looking for life existed, or will exist – you need them to be at least at our level of technology, give or take 50 years for either of us, and within 100 light years of earth (at a stretch). And, however we communicate with each other, that signal cannot travel faster than light.

To put this in illustrative terms, let’s use what I’ll call the time-overlap thought experiment: pick a number between 1 and 4 billion: that number is how many years back in time you will travel to a random place on earth. Another person does the same. What are the odds that the two of you will now meet up? And even if luck be damned, and incredibly you both picked the same number, and live at the same time on earth – you need to make contact before you die of old age – but let’s say you’re both different ages, both or either of you could be very young or very old. Where do you look? Which direction do you start out in? What do you look for?

It’s the same with aliens. Maybe they existed but died out ages ago? Maybe they are only now discovering the internal combustion engine? Maybe somewhere out there a CO2-laced volcanic world orbits a yellow star that will evolve intelligent life in many eons to come? Or maybe they are just like us typing blogs on their internet right now, but are just too far away. Who knows?

It’s fascinating to consider, but it’s speculation without resolution. Ultimately, the notion of alien visitors (especially given the total lack of proof) should be dismissed out of hand. The existence of alien life, either good or evil, is totally irrelevant to us. So although it’s overwhelmingly likely they are out there, by the same principle it’s overwhelmingly certain we will never ever know about each other.

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6 Responses to “Aliens exist, but you shouldn’t care”

  1. Daniel Says:

    You can’t put away the possibility that our planet is the only one that can sustain life in the whole universe, however small that chance it is.

    Given the almost infinite time span of the universe, the chance that it will have, at a given time, only one planet with life is almost 100%. Of course we can’t tell if we are this single planet with life at such a rare moment or not, and that’s why we can’t scratch any of those possibilities.

    Remember that the time span is almost infinite and any possible combination of planets is bound to happen sometime 😉

  2. evanescent Says:

    Daniel, the latter part of your post seems to contradict the first. Are you saying that the almost limitless nature of the universe argues for or against a unique earth?

    Whilst earth may or may not be unique, given that it’s already happened once, the fact that it CAN happen is 100% – and there is nothing particularly “special” about earth, given its composition and distance to the sun – and given an almost endless number of solar systems to choose from, I think the odds of another earth are, in astronomical terms, pretty darn high.

  3. Daniel Says:

    Actually, I’m not arguing for or against the uniqueness of earth. Maybe I’m doing both.

    To prove something nearly impossible just isn’t enough, given the almost infinite timespan. It’s almost a certainty that nearly impossible will happen at some point in time.

    When we state that the chances of earth being unique is pretty darn high, that’s pretty much all we can say. We can’t just discard that pretty damn small chance of earth being unique just yet. It’s still a chance. Unless you can prove it’s actually impossible.

    What I’m arguing is that the chance that earth is unique may be just as high as there being two planets like earth, or three or 107.

    I’m just being an annoying statistician 😛

  4. evanescent Says:

    Well to continue being picky (:p), what you’re saying is true albeit trivial, and if offered as an argument is an Appeal to Ignorance.

    I don’t agree with you here:

    “What I’m arguing is that the chance that earth is unique may be just as high as there being two planets like earth, or three or 107.”

    I don’t think this is statistically sound. Since we agree that given the universe’s virtually limitless opportunities to generate a planet of earth-type composition, and your agreement that given enough instances the probability of any particular instance obtaining approaches 100% (but never quite reaches it, since the universe is not actually infinite), the odds are not exactly 50/50 but in fact lean heavily towards a second earth. Add onto this the fact that it has already happened once – we have absolutely *every* reason to suppose it has/had/will happen again, and *no reason* to suppose it won’t/hasn’t.

  5. Daniel Says:

    “Well to continue being picky (:p), what you’re saying is true albeit trivial, and if offered as an argument is an Appeal to Ignorance”

    No, not at all… I’m just saying that statistical possibility, no matter how big it is, is not certainty (although, if I would bet my money on any chance, it would be on the “pretty darn high” one). All we can say until now is that earth-like planets and the ocurrance of life on some of them are probable, or highly likely to occur. But not at all certain.

    “I don’t think this is statistically sound. Since we agree that given the universe’s virtually limitless opportunities to generate a planet of earth-type composition, and your agreement that given enough instances the probability of any particular instance obtaining approaches 100%”

    It was just a figure of speach, but I guess I deserved that (:P). I agree with you ’till this point.

    “the odds are not exactly 50/50 but in fact lean heavily towards a second earth”

    A second, a third, a fourth earth… or maybe just one, just ours. There’s no way to know in wich particular instance we are right now… just probability. Again, I agree that chances are pretty high. If I had to, I would bet my money on that chance. We’re just not 100% certain that there is in fact, more than one earth. Almost 100% certain, maybe 99.9999999% haha

    “we have absolutely *every* reason to suppose it has/had/will happen again, and *no reason* to suppose it won’t/hasn’t”

    *almost every* reason and *almost no reason*. That’s the whole point 😉

    Best regards.

  6. Michel Says:

    Totally agree on this blog. The problem is that humans are looking for life in a form that is used to them. Nasa searches for planets that have an atmosphere were ‘life’ is possible according to human measures. There’s a possibility that there is other life but not in a form as humans.


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