Why we might be alone in the Universe

[Gawdzilla Sama]

Long distance relationships never work out.

I met my wife online. Me, St. Louis. Her, Albuquerque. We exchanged in excess of 20,000 messages (each) before we actually met. We will have been married nine years in July.

Now if she had been on Aldebaran...

[Fireball]

Given the distances involved, whether life exists anywhere else is pretty much moot. It's probably just as well. The apex predators that may exist elsewhere will likely be every bit as vicious and petty as mankind, and possibly worse.

[Gawdzilla Sama]

Have you seen the mini series "Alien Planet"? https://www.imdb.com/title/tt0453446/?re...f_=nv_sr_2

[Anomalocaris]

Long distance relationships never work out.

I met my wife online. Me, St. Louis. Her, Albuquerque. We exchanged in excess of 20,000 messages (each) before we actually met. We will have been married nine years in July.

Now if she had been on Aldebaran...

A wifely nag will take a long time to cross 65 light years......

---

“Might” means probability of what?

Alone in the universe as in which specific definition of the universe?

If any technological civilization evolved somewhere in the universe within the period when our solar system existed, and that civilization made an concerted effort to show us an unmissable sign of its existence that conquers any distance or intervening obstruction,  that civilization still has to be in a very tiny portion of the entire observable universe, roughly a volume equal to 0.5% of the total observable universe, for it to even be theoretically possible for us to see those signs.

The video answers (or at least explores) the first two questions. The third is unrelated to its thesis.

I see the video more as a counterpoint to those claiming that life elsewhere in the universe is likely given the size of the observable universe and (apparently) large number of earth-like planets.

We have one data point, it argues, and there are plenty of other factors to consider.

The third is entirely relevant to the thesis.   Even if we exhaustively eliminated any possibility of any technological civilization from every part of the entire universe whence any indication of any technological civilization can even be theoretically be accessible to us,  we would have ruled out the presence of technological civilization from just a few % of the volume of the observable universe, and just for one single conical slice of time.    But we are so far from having exhaustively ruled that out, that to first, second and third degree of approximation we can say we are 0% of the way there. 

In other words, we are not in, and has no prospect of ever being in, any position to observationally contradict the probabilistic assessment that other technological civilization likely exist in some numbers elsewhere in the universe.

Even if the average distance between any technological civilization that ever arise is 1 billion light years when they arise, there can still be >10,000 technological civilizations that arose within the observable volume of universe.

[BrianSoddingBoru4]

Given the distances involved and the volume of space to be adequately explored, the difference between extraterrestrial, technologically advanced civilizations existing and not existing is very roughly zero - what you can't observe looks an awful lot like what isn't there.

Boru

[Alan V]

Long distance relationships never work out.

I met my wife online. Me, St. Louis. Her, Albuquerque. We exchanged in excess of 20,000 messages (each) before we actually met. We will have been married nine years in July.

Now if she had been on Aldebaran...

Yeah, I was just kidding.  I met my own wife through correspondence when she lived in the Philadelphia area and I lived in the Dallas area.  We have now been happily married for 25 years.

I wonder how much postage would cost to Alpha Centauri ?

[Gawdzilla Sama]

I met my wife online. Me, St. Louis. Her, Albuquerque. We exchanged in excess of 20,000 messages (each) before we actually met. We will have been married nine years in July.

Now if she had been on Aldebaran...

Yeah, I was just kidding.  I met my own wife through correspondence when she lived in the Philadelphia area and I lived in the Dallas area.  We have now been happily married for 25 years.

I wonder how much postage would cost to Alpha Centauri ?

There was a short story I read back in high school. A guy notices that the farther a letter has to go the shorter the delivery time. Across town, four days. Neighboring country, three days. Outer Mongolia, two days.

So, he addresses a letter to Alpha Centauri Main Post Office. He puts it in his mailbox and before he can go back inside a letter carrier is there with his reply. The letter announces that as Earth has discovered the Interstellar Postal System we are now members of the Galactic Federation.

[vulcanlogician]

The third is entirely relevant to the thesis.   Even if we exhaustively eliminated any possibility of any technological civilization from every part of the entire universe whence any indication of any technological civilization can even be theoretically be accessible to us,  we would have ruled out the presence of technological civilization from just a few % of the volume of the observable universe, and just for one single conical slice of time.    But we are so far from having exhaustively ruled that out, that to first, second and third degree of approximation we can say we are 0% of the way there. 

In other words, we are not in, and has no prospect of ever being in, any position to observationally contradict the probabilistic assessment that other technological civilization likely exist in some numbers elsewhere in the universe.

Even if the average distance between any technological civilization that ever arise is 1 billion light years when they arise, there can still be >10,000 technological civilizations that arose within the observable volume of universe.

Finding a second data point is crucial to making any determination as to how common life is in the universe. As it stands now, the size of the universe cannot tell us a thing. In order to make any claims about the abundance of life in the universe (or lack thereof) we need:

1) To find another example of life. (We haven't found one yet.)

OR

2) Figure out the probability of abiogenesis. (We have no clue how probable abiogenesis is.)

As for technological civilizations and/or advanced life on other planets, we can assume that IF abiogenesis is fairly common, advanced lifeforms in the universe will also be very common. If advanced life forms are common, then it seems plausible that other technological civilizations exist somewhere out there.

The issue discussed in the video is that (for all we know) the chance of abiogenesis could be so infinitesimally small that even in an area many times the size of our observable patch of the universe, it may be unlikely for it to happen more than once.

If this is true, then it is useless to speculate about other technological civilizations because (without abiogenesis) such civilizations won't even have a chance to emerge.

[polymath257]

I thought this was a logical and realistic analysis...

Interesting video. I don't particular find his reasoning to be convincing when he attempts to deal with the early existence of life on Earth. The problem with his analogy is that there is an artificial time constraint on the 'prisoners' picking the lock of their cells. For this analogy to hold up, there would have to be some strict time limit on when life has to get started on a newly formed planet. Unless the parent star has to be in a very specific stage of its development (T-tauri, maybe?), this doesn't seem likely.

On the other hand, we are dealing with an N=1 scenario at this point.

But, I can go a bit further. While life got started very quickly on Earth, the transition to Eucayotic life (complex cells) and multi-cellular life took a pretty long time. So, while bacterial (procaryotic) life was around within a few hundred million years after the Earth cooled enough to have liquid water, eucaryotes don't appear for about another 2 billion years and multicellular life took almost another 1.5 billion years. This suggests both of these stages are much harder to get than life itself. Once we got multicellular life, getting to intelligent life took another half a billion years. Difficult, but not the hard step.

Because of this, my *guess* is that bacterial life is common in the universe but complex cells and multicellularity are much less common. Getting through the 'oxygen crises' where molecular oxygen becomes common also seems like a tricky step.

Another factor for *intelligent* life is how long a technological civilization can last without destroying itself. Humans only went through the industrial revolution a couple hundred years ago. We managed the first radio transmission about a hundred years ago. But it looks like we now have the power to kill ourselves off in multiple ways (nuclear, climate, etc) and whether we will keep this technological advance is far from certain.

What if technology is counter to long term survival of the species? Maybe no species manages to be technological for more than, say, 10,000 years. This is a *blip* on the cosmic scene. If this is the case, the likelihood of two technological civilizations existing at the same time within a galaxy starts to become pretty low.

We may be alone simply because technology is dangerous and technological civilizations don't last very long.

[ignoramus]

Long distance relationships never work out.

I had 2 kids with a lady a long time ago in another galaxy.
It didn't work out, but the child support payments were killing me so I had to move far far away to somewhere where they'll never find me!

and here I am...