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Why We Haven’t Met Any Aliens

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Re: Why We Haven’t Met Any Aliens

#111

Post by ck2 »

extension wrote: post #106
ck2 wrote: post #95

Finding earth (or another earth-like planet with people) would be like finding a particular particle of sand on a beach. The universe is mind numbingly big - try to imagine how big and then quadruple that size and you are still wrong. Just the observable universe is nearly 50 BILLION lightyears in each direction (there could be more and it's expanding). (remember the deficit/debt demonstrations of "million" vs "billi…

We don't need to find a particular grain of sand, we just need to find a grain of sand that's a particular shape or color. How rare such grains are is the big question. Everything we know tells us that they should be everywhere, but they aren't. We can see for 93^h^h47 billion light years in all directions. That's a pretty big ball-o-space. Plenty to observe. And if we find ETI, even at distances that preclude ever i…

What if we are not just observing the wrong places but the wrong time.

Our observations are millions of years old.

Re: Why We Haven’t Met Any Aliens

#112

Post by nikcub »

I think it is because the Drake equation[1] over-estimates the chances of intelligent life forming.

A common average result for the Drake equation is 10,000 habitable planets capable of sending signals in our universe. But if you look at the equation and estimates they are a bit optimistic.

If you take fℓ from the equation, I don't think simply being of the right composition in the habitable zone is enough. The Earth formed life because of the moon, because we had been shiften off our axis which formed seasons, because we were made of enough iron to form a magnetic field, and we just happen to form a moon which protected the Earth from space debris and gave us tides (in short, the moon and magnetic field are essential to life on Earth, as well as the composition of the planet).

That is a lot of 'ifs' to add to the equation, which brings the chances of a planet even in the habitable zone having the same life-bearing characteristics as earth much, much lower. Even with thousands of planets in the habitable zone the chances of finding one that has a magnetic field, the right temperature, a moon, etc. are very very slim and when multiplied back into the Drake equation brings the result back to lower than 1 - meaning we are a complete fluke.

There is also the time portion of the equation. The Earth is 4.6B years old, and we have been capable of sending signals for only 100 years of that time. Even if our civilization survives for another 10,000 years it is still 10,000 years divided into 4.6B years - so even with the complete fluke of an Earth-like planet being created in a habitable zone takes place, we are still 1 in 460,000 chance of being around at the same time. If Drake gives us 10,000 possible habitable planets with life, the 1 in 460,000 factor of time brings it back to a lot less than 1 again.

I believe that Keppler will continue finding planets in the habitable zone, but they will look more like Mars and Venus than anything like Earth.

I find it interesting that the Drake equation, created to show that there must be other intelligent life, can today be used to show that we are very unique when it is adapted with what we know today. [1] https://en.wikipedia.org/wiki/Drake_equation#The_equation

Re: Why We Haven’t Met Any Aliens

#113

Post by aamar »

Yhippa wrote: post #36
aamar wrote: post #16

The physicist David Deutsch makes the point that there is no real way to distinguish a consistent, convincing virtual reality from reality itself. Therefore, there is no real moral difference between richly populating such virtual worlds (once we can construct them--we can't quite, yet) and populating actual other planets. Nick Bostrom would say that even using the word "actual" is probably wrong, since we're likely…

Interesting point. Based on what the author of this post is saying I wonder if the average human were given the option to enter a virtual reality where they could set the parameters to whatever they want would people know the difference or even care to find out? If you could have any beautiful woman you want, a great body, and great financials who would want to leave that fantasy?

One obstacle might be that by entering the VR, you'd be ceding a lot of control to the people "outside" your reality--they might gain physical advantage over you or hack your VR.

But if that concern could be definitively answered--and I think it could--then quite possibly the VR is a good move. Maybe any preference for our outside, non-simulative reality will in time be seen as narrow-minded chauvinism.

Re: Why We Haven’t Met Any Aliens

#114

Post by aamar »

extension wrote: post #106
ck2 wrote: post #95

Finding earth (or another earth-like planet with people) would be like finding a particular particle of sand on a beach. The universe is mind numbingly big - try to imagine how big and then quadruple that size and you are still wrong. Just the observable universe is nearly 50 BILLION lightyears in each direction (there could be more and it's expanding). (remember the deficit/debt demonstrations of "million" vs "billi…

We don't need to find a particular grain of sand, we just need to find a grain of sand that's a particular shape or color. How rare such grains are is the big question. Everything we know tells us that they should be everywhere, but they aren't. We can see for 93^h^h47 billion light years in all directions. That's a pretty big ball-o-space. Plenty to observe. And if we find ETI, even at distances that preclude ever i…

Nit: 47 billion light-years in all directions; 93 billion light years is the diameter.

Re: Why We Haven’t Met Any Aliens

#115

Post by [deleted] »

freshhawk wrote: post #99
firefoxman1 wrote: post #80

Earlier quoted context omitted.

Yeah kind of like how bacteria don't know they're under a microscope.

Consider your analogy stolen for future use! They're all down there thinking "why aren't there any alien bacteria sending us some chemical messages already? It's clearly the best way to communicate"

[deleted]

Re: Why We Haven’t Met Any Aliens

#116

Post by extension »

There is this assumption that the ambition of humanity should be to physically expand far into space. But why exactly? Spanning large distances isn't a very interesting goal per se. We will learn a lot of cosmology and physics in the process, but I would imagine that once you've seen a few thousand stars, nebulae, and black holes up close, you've pretty much seen them all.

The idea of building a giant computer (or turning into one) seems a lot more interesting. If that's what we're doing, then those people making social networks and video games are on the right track. In this case, we probably wouldn't expand physically until we run out of energy for computation, and our own sun has enough of that to last us a long time.

Re: Why We Haven’t Met Any Aliens

#117

Post by itmag »

Some more options:

-Life is around but it's nowhere near our way of thinking and functioning. Maybe it's a gas cloud which takes a billion years to "think" a single thought. Who's to say that an alien lifeform's "neocortex" and utility function is going to be anything but incomprehensible to us? (Counter-argument: certain patterns repeat independently in nature, for instance I read somewhere that the design pattern for the eye has been created independently by evolution like 40 times).

-Life is around and we've already made contact with it (ie UFOs).

-Life is out there but it's consciously avoiding us (Prime Directive-style).

Re: Why We Haven’t Met Any Aliens

#118

Post by Sandman »

The article's last point strikes me as a bit odd. The religious fundamentalists will be the ones who make scientific advances that are necessary to travel across the universe and meet alien species? Judging from the fundamentalists' past actions, allow me to stay sceptical about that.

Re: Why We Haven’t Met Any Aliens

#119

Post by extension »

ck2 wrote: post #111
extension wrote: post #106

Earlier quoted context omitted.

We don't need to find a particular grain of sand, we just need to find a grain of sand that's a particular shape or color. How rare such grains are is the big question. Everything we know tells us that they should be everywhere, but they aren't. We can see for 93^h^h47 billion light years in all directions. That's a pretty big ball-o-space. Plenty to observe. And if we find ETI, even at distances that preclude ever i…

What if we are not just observing the wrong places but the wrong time . Our observations are millions of years old.

They are millions of light years away, but there is no absolute time frame in which our observations could be called "old" or "new". You can choose to think of far away things as "the past", if you like. But the point is, that doesn't make it any less cool.

EDIT: Actually, I missed your point, which was that far away things have less history in which intelligence could evolve. This is true, but the amount of history we can observe is still staggeringly large. Far too big to eliminate the paradox.

Re: Why We Haven’t Met Any Aliens

#120

Post by iso8859-1 »

aamar wrote: post #46
brandall10 wrote: post #24

Let's imagine there are billions of planets out there (a true Sagan-esque billions) which have spawned intelligences that have achieved interstellar travel - ie. they have the ability to actively seek out and communicate with others of similar ability. Perhaps like the United Federation of Planets in Star Trek, except many, many of these, separated from others by various degrees of intelligence or ability. Let's imag…

True, but if these super-advanced aliens are populating many planets, then we'd presumably be able to detect them somehow, irrespective of whether they care about us. It may be electromagnetic leakage or Dyson spheres or any of a number of other signs of artifice.

Maybe our universe runs in their VM. I don't know how you can assume that we would be able to detect anyone. If they are smarter than us, they'd know how to hide.
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