Author Topic: Some space science Qs  (Read 1955 times)

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Offline Hawkeye

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Re: Some space science Qs
« Reply #15 on: October 23, 2013, 10:25:31 AM »
1. Universe is 13.82 BY old.

While the universe is 13.xx billion years old, you can cut the first couple bn years, as there weren´t enough heavy elements (i.e. anything above H and He) to support rocky planet as those (the elements, not the planets :)  ) were generated via supernova explosions as the universe aged (not that this changes a whole lot, mind you).

The main problem with finding other intelligent life in the universe is twofold, as I understand it.

One: The universe is bloody big. Even if there would be thousands of advanced species out there right now, the distances between two of them (assuming somewhat even distribution) would be what, one species per several hundred thousand galaxies.

Two: Even if a thousand advanced species would evolve in a single galaxy, the timespans involved are mindbogglingly large.

Say, we start counting from Big Bang +5 billion years as the time when enough heavy elements were there to support life.
Lets also assume it takes another 3 bn years for life to evolve from simple singular cells to something intelligent.

This leaves us with more than 5.5 billion years over which those 1000 species are spread out. The chances that two of those achieve the level of radio use/space flight at the same time are incredibly low.

Arthur C. Clark called this: Your space explorers will find "Angels or Apes" but no men

Why? Consider the history of Planet Earth. Let the height of the Empire State building represent the 5 billion year life of Terra. The height of a one-foot ruler perched on top would represent the million years of Man's existence. The thickness of a dime will represent the ten thousand years of Man's civilization. And the thickness of a postage stamp will represent the 300 years of Man's technological civilization. An unknown portion above represents "pre-Singularity Man", the period up to the point where mankind hits the Singularity/evolves into a higher form/turns into angels. Say another dime. Above that would be another Empire State building, representing the latter 5 billion years of Terra's lifespan.

If you picked a millimeter of this tower at random, what would you most likely hit? One of the Empire State buildings, of course. So, assuming only one civilization develops on a planet, chances are the first-in-scout starship Daniel Boone will discover mostly planets that are currently empty of alien civilizations (but they might have an almost 50% chance to discover valuable Forerunner artifacts or other paleotechnology).

If you only use the section with an alien civilization, you have a ruler and two dimes worth of apes and angels, and a postage stamp worth of near Human civilization. Ergo: apes or angels, but not men.


Ralph Hoenig, Germany
 

Offline Erik Luken

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Re: Some space science Qs
« Reply #16 on: October 23, 2013, 11:06:16 AM »
 

Offline Bgreman

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Re: Some space science Qs
« Reply #17 on: October 23, 2013, 12:55:26 PM »
This still leaves the Fermi paradox out there.  My suspicion on that is that it means that interstellar travel is just too energetically (and elapsed time) expensive for intelligent life to do it.  You would have to have organisms with lifetimes 100s or 1000s of times longer than ours in order for the beings that funded the travel to economically benefit from it at the speeds that are realistically obtainable.

John

The bolded portion implies a rather singular (and anthropocentric) motivation.  Humans colonized uninhabited lands for a variety of reasons.  Economic gain was certainly one of them (and maybe the most important one in the settling of the New World), but so was pioneerism, religious persecution, nomadic wandering, overcrowding, and untold others.  Whether one or more of these would apply to a civilization with a non-human psychology (if it possessed what we think of as 'psychology' at all) is tough to predict.
 

Offline TallTroll

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Re: Some space science Qs
« Reply #18 on: October 24, 2013, 04:24:11 AM »
>> This still leaves the Fermi paradox out there.

I don't buy the Fermi Paradox. Fermi was of course quite brilliant, but he only had access to the knowledge that existed in his lifetime. According to Wikipedia, he proposed the paradox in 1950, 10 years before the first laser, and thus had no concept of fibreoptic communications. Also, if you are willing to allow the possibility of a genuinely advanced civ having developed a practical and economically useful FTL drive, surely they would have an FTL communications system. If you can move a physical object at FTL speeds, it seems likely that moving information would be at least as easy, and since we currently have no idea how you might do that, we can't even look for it.

In Earthly terms, imagine a remote Native American tribe who somehow have avoided contact with with the US, or a perfectly real uncontacted tribe from the Amazon suddenly developing radio technology today. Suddenly, they would "see" vast quantities of communication going on around them, including very close to them, of which they had no previous inkling. It's quite possible that we are in that position, with loads of evidence of other civs all over the Solar System, which we just don't know how to look for
 

Offline sloanjh

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Re: Some space science Qs
« Reply #19 on: October 25, 2013, 01:18:13 AM »
The bolded portion implies a rather singular (and anthropocentric) motivation.  Humans colonized uninhabited lands for a variety of reasons.  Economic gain was certainly one of them (and maybe the most important one in the settling of the New World), but so was pioneerism, religious persecution, nomadic wandering, overcrowding, and untold others.  Whether one or more of these would apply to a civilization with a non-human psychology (if it possessed what we think of as 'psychology' at all) is tough to predict.

By "economic benefit" I meant utility, not money, i.e. whatever floats one's boat.  And how many of the examples cited would have set off if the expense (and for that one I mean in the sense of resources)  was a significant portion of the host culture's economic output and the voyagers would not arrive for 100s or 1000s of generations?

I'm not saying it hasn't ever happened, I'm saying that I suspect that no species has evolved in our galaxy for whom the resource/time barrier of interstellar colonization is low enough that the expectation value of the number of granddaughter colonies spawned by a daughter colony is greater than one, which means that our galaxy hasn't gotten the exponential growth in colonized worlds that is at the core of Fermi's paradox.

BTW, Charles Stross just put out a novel involving a future civilization that deals with slow-boat colonization.  Neptune's Brood - it's a (loose) sequel to Saturn's Children.

John
 

 

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