The Instigator
Pro (for)
7 Points
The Contender
Con (against)
23 Points

given the sheer size of the universe, the most reasonable view is expecting that alien life exists

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after 5 votes the winner is...
Voting Style: Open Point System: 7 Point
Started: 6/23/2012 Category: Science
Updated: 4 years ago Status: Post Voting Period
Viewed: 1,280 times Debate No: 24406
Debate Rounds (3)
Comments (3)
Votes (5)




given the sheer size of the universe, the most reasonable view is expecting that alien life exists

there could be, and the most reasonable explanation is, life outside our planet. at least basic life, maybe intelligent, exists.

first consider a basic idea in the size of our universe. if an alien life existed and sent us a signal at the speed of light. even at the speed of light, over 186000 miles per second... per second, by the time the signal got to us, that alien civilization probably rose and fell over billions of years. eg, if they sent it from fifty billlion light years away, and a civilization only lasts a few billion... at teh very most... then by deifinition that civilization probably no longer exists.

i'm about to show some math in the following argument, a little more than basic math. my point is not to get caught up in the minutia of the math, but to simply establishthe point. i did want the math shown though as i did the calcuations for my own edification, might as well share.

a CNN article estimates that the universe is156 billion light years across. (with the article also saying that the universe could be larger, as that figure is only what is known to exist based on the data gathered) the milky way is 100000 light years across. that means volume wise, the milky way is 0.00006% of the universe. (milky way divided by the total universe is the percent). doing the math, comes out to.... our milky way is the size of a ping pong ball, and the universe is the size of a cube, that is 25 miles in all directions. that's a massive cube for a lone ping pong ball, wouldn't ya say? our planet and us individually would be smaller than a speck of dust.

granted, however, doing some basic math, we can see the "cup v. ocean" thing is not quite accurate, according to hypertext book online, the ocean is 321,000,000 cubic miles in volume. hopefully i didn't screw up any math....

---basic algebra: 0.00006% = (X / 321,000,000) *100 ====> x= 193 square miles of ocean is analogous to the equivalent of the milky way and universe. the ocean is hard to grasp itself, so another example could be helpful. (but just look at google maps and see how small 200 miles is in relation, then check out this website to see how small that is, deep )

---more: 0.00006% = (1 inch cubic square/X)*100 ====> x = 1666666 cubic inches, or 138888 cubic feet, or 25.5 cubic miles.... 1 cubic inch is about the size of a ping pong ball, which would be the equivalent of the milky way, with X being something far larger than any of the largest buildings, cubed. the worlds largest is only half a mile tall... you'd have to stack more than fifty of those on top of each other (make it into a pole), and then make it three dimensional in the other two directions, so drive twenty five miles each direction, setting up another massive pole at each of the four corners of the box, before you put your "cap" on it. look up in the sky twenty five miles, turn left, do some loop de loops in a parking lot, and consider all that in relation to a ping ball ball, and speck of dust. that's a massive cube for a lone ping pong ball, with us smaller than a speck of dust, wouldn't ya say?

also, according to chacha answers (maybe not the best source, but still authoritative) and various internet hearsay, only less than one percent of the universe has even been at all significantly explored by telescope. (yet we don't even know enough to say whether there's life in this less than one percent, either) that means our meek neck of the woods is earth, perhaps our ping pong ball the milky way, and maybe what we can see... in relation to the 25 mile cube, one percent is only a quarter of a mile, cubed.

--- if we used the explored universe, if we used one percent of the universe to compare, which is the amount of explored universe it's be quite a lot bigger than the 200 miles of ocean. if we used the earth to compare a cup of water to the ocean the cup analogy probably ain't that bad. [[[i couldn't help but do the math on earth's volume in relation to a cup v ocean.... 321000000 cubic miles is 46224000000 cubic inches.... 0.00006% = (X / 46224000000) *100, X = about 28000 inches, or less than half a cubic mile, represents earth in the ocean universe, still pretty far off from a cup. ]]]

some perspective on how big our planet and sun is compared to the largest out there:

--interesting extra point. if the speed of light is the fastest light can go, how fast can a "car" go on that 25 mile cubic box? light travels 186,000 miles per second, or 5865696000000 trillion miles a year. times that by 156 billion light years in width. that means the universe is 91,504,857,600,000,000,000,000 miles in width. that's 91.5 sextillion miles. sextillion comes quintillion comes after quadrillion, after trillion. so we could say you can only travel 5865696000000 trillion miles a year/91.5 quintillion miles an hour (if the speed of light per second is the max, then per year is also max... and that number is the fraction of the total that can be drove) or 6.4e-11 miles an hour, or 0.000000000064 miles an hour. how long would it take to travel a mile? 0.000000000064 = 1/X, x=15625000000 hours, or 1,780,821 years.... at the speed of light equivalency maximum that we can drive. if we traveled at the fastest that we are currently capable of at 25,000 miles per hour. that comes out to .... very small speed to say the least. to travel the whole 25 miles of one side would take forever let alone all the sides and everywhere...


another point. i've heard there are 49 sextillion stars in the universe. that means, if we say just for the sake of argument, that life exists one in a quadrillion (after trillion, which is the largest we ever really ever talk about in most day to day life)... that means life would exist in 49 million of those places.
1 000 000 000 000 000 / 49 000 000 000 000 000 000 000

if we assumed each star and nine planets like our own, we could perhaps consider the number might be even higher, as there's more chances that life could exist.


Before I get into this, I'm going to nail some things down...

Alien -
Definition: Extraterrestrial.

Life -
This is going to be looked at in the way that most reasonable people would understand it.

Exist -
Definition: To have life.

Examples of things that are alive: Animals, humans, and plants.

I'm going to specifically exclude all forms of deities, space, stars, and energy based life (including dark energy), otherwise the debate becomes ridiculous. Also, life must have some mass, and therefore matter.

Sheer -
Definition: Nothing other than; neither more nor less than; that and nothing else. This is a pretty standard,denotative meaning.

Size -
Definition: Volume.

Universe -
When talking about the universe, we will be talking, specifically, about the observable universe.

Restating the issue: Given nothing other than the volume of the universe, the most reasonable view is expect that extraterrestrial life exists.

Not Enough Information:
Given only the volume of the universe, we don't even know if there is matter in the universe. Therefore, we have no possible way of knowing if life even exists, let alone it being reasonable.

Even if we use the current estimates for volume and critical density of the universe, we still have no reason to believe that there is life, or any sort of structure. We were not given the idea of physics, and therefore know nothing about gravity. So, for all we know, the universe could have all mass evenly distributed; this would leave us with roughly 1 proton per 4 cubic meters (1). Those are unreasonable conditions for any form of life.

In short, we have nowhere near the amount of information required to determine that there is life, let alone find it reasonable to expect alien life to exist.

Fermi's Paradox:
"The apparent size and age of the universe suggest that many technologically advanced extraterrestrial civilizations ought to exist.
However, this hypothesis seems inconsistent with the lack of observational evidence to support it." (2)

I wanted to formally mention this, as it is an important issue.

To be fair, you did start to address it, but you really only stated that alien life could be too far apart in time, or too far away, distance wise.

Being too far apart in time doesn't do anything for your argument, seeing if the alien life is dead, it no longer exists (which you already mentioned).

If the distance was an issue, then we should have observed alien life that ceases to exist. Granted, that presupposes that intelligent alien life existed long before terrestrial life, but you already stated that it could have. If we saw any observable evidence that confirms there was alien life, then Fermi's paradox wouldn't be an issue.

Habitable Zone:
The habitable zone is the zone in which it is theoretically possible for the planet to have liquid water on its surface. (3)

Basically, we can use this to get a more accurate number for possible planets life can be sustained on. Although, it has been suggested that life can be sustained elsewhere, the most 'certain' would be an article that basically says that it is theoretically possible, but it's not very practical. (4)

Anyway, there isn't much data or very many sources I can find that even attempts to guess the number of planets in the habitable zone for the entire universe, but there are some figures for our galaxy. One of the most recent set of articles was based off NASA's Kepler mission, which extrapolated the data and came up with a total of 50 billion planets, in our galaxy, and only 500 million reside in the habitable zone. (5)

Armed with that information, we can do more accurate calculations. But, we still need a little more information...

There are approximately 6 x 10 ^ 22 stars (6), so if we assume that our galaxy is representative of the universe (which is highly unlikely) we can at least get some sort of approximation...

In our galaxy, there are around 170 billion stars. (6) This makes the ratio of habitable planets to stars approximately 0.00294.

Now, if we multiply that by the number of stars in the universe, and divide by the completely arbitrary number you decided, we get around 176,470 planets with life. Now, we've made gigantic assumptions, and it is in no way close to statistically significant, even if we account for significant figures...

I should note, that 176,000 is far from the 49 million, which again, is entirely based on some arbitrary factor of 1 quadrillion, and numbers that vary wildly.

Given only the size of the universe, which is all that was given, we have absolutely no way to determine if there is life, let alone determine that the most reasonable view is to expect alien life to exist. In addition, Fermi's paradox has not been resolved, and there no statistical evidence that supports the idea that alien life exists.

Debate Round No. 1


i will grant that information you gave, such as the habitable zone, helps to infer more accurately the likelihood that life exists. but, even you found with your calculations, big assumptions and all, that life probably exists based on the assumptions you made. the figure may have not been as high as we might like, but it is what you concluded.

also, my numbers may not have been considerate of all factors as it could have been... based on size alone. but, based on sheer size, we can still infer that even with restrictions like the habitable zones, the numbers are so high that we'll still come out to a number of planets with life.

as to fermi's paradox, it's not much of a paradox. we live in an unassuming corner of the universe. intelligent life might nto be much mroe intelligent than us... which means they wouldn't be able to communitate with us. they might be less intellgient, again no communication or signs. they might be more intelligent, btu that don't mean they are enough to communicate or show signsto us. especially given the distance and how long it takes even light to travel as far as it does.


Not Enough Information:
Why did pro completely ignore this segment in my original argument? Not enough information is, by far, the most important point I've made.

Even though pro did not address this issue, I will expand my argument...

Pro related the universe to various things in round 1, so I'll do the same, to make things clear.

Say we are told there is an extremely large, but still finite box (the universe). Then, someone argues, with only that information, that the most reasonable view is to expect a banana (alien life) to exist in it.

It is clear to any reasonable person that there is nowhere near enough information given to come to that conclusion, let alone declare it to be the most reasonable view. Primarily, because we know nothing about what is in the box or how long it has been around.

A More Reasonable View:
Instead of just arguing that expecting alien life to exist is the most reasonable view, I'm going to provide a more reasonable view. By doing so, it proves pro's argument is incorrect.

The alternative view is as follows:
We do not have enough information to definitively determine that there is or is not alien life in existence.

This, by definition, is more reasonable, as it is more agreeable because it is a fact; we do not have definitive proof that there is or is not alien life in existence.

Pro claims that I found that alien life probably exists, but I clearly did not. I made it very, very clear that the results were statistically insignificant, and completely useless.

If pro is so certain, then why were no actual significance tests done? It would be a simple and straightforward way to refute the argument that the numbers are not statistically significant...

I will not perform a significance test first, because any reasonable person can see that the numbers I arrived at do not provide any evidence. Just take a look at how wide the numbers vary for the number of stars in our galaxy... Using multiple sources, you get anywhere from 200 billion to 400 billion. (7) Another example is the number of stars in the universe; pro found that it was 49 sextillion, while I found that it was 60 sextillion. There are several other sources that widen the range from 30 sextillion to 1 septillion. (8) Also, don't forget the completely arbitrary factor of 1 quadrillion...

Significance tests aside, an easy way to show there is no significance is by using significant figures... 1 quadrillion has no significant figures, as it was not measured and completely arbitrary, therefore our result has no significant figures. (9) Therefore, the results are not significant.

Furthermore, these calculations have nothing to do with the initial statement, because we were given only the size of the universe.

Fermi's Paradox:
Pro's refutation is that, "it's not much of a paradox." It is, by definition, a paradox. (10) Also, it is unresolved, so I don't see how pro can dismiss it so easily. (2)

Anyway, pro goes on to talk about alien intelligence and the ability for them to communicate with us, but pro is just restating what she already said, rather than addressing the objections I raised.

Pro has ignored crucial objections and parts of my argument, so I began to expand my argument in an attempt to salvage this round. More specifically, I've expanded on my not enough information argument, provided a more reasonable view, proven the calculations yield numbers that are statistically insignificant, and refuted pro's attempt at refuting Fermi's paradox.

(10) Definition: 1. A self-contradictory proposition. 2. An opinion or statement contrary to the commonly accepted opinion.
Debate Round No. 2


dairygirl4u2c forfeited this round.


Seeing pro forfeited the round, there isn't much I can say... This is my first debate and I'm new to DDO, so I don't know what the standard protocol is for someone forfeiting the final round.

That being said, I suppose I will just leave the arguments I've made as they are.

Anyway, it was a fun debate and I enjoyed it. I guess the rest is up to the voters...
Debate Round No. 3
3 comments have been posted on this debate. Showing 1 through 3 records.
Posted by Ore_Ele 4 years ago
Shouldn't the VANA be voting for PRO?
Posted by dairygirl4u2c 4 years ago
i'll also point out. as long as we can conclude that life exists one in every "half of the stars" out there, then we can conclude that life probably exists on a planet other than our own.
that is, half of the stars posted by con is 3 * 10 ^ 22
one in 30 000 000 000 000 000 000 000

again just by sheer size alone, we'd expect that life would exist one in that many stars. if we could conclude that, we could conclude that life probably exists somewhere else in our universe.

also, there's lots of signs that life (and more especially water) existed on mars at one point which shows even in our own solar system, life isn't as limited in probablity as one might think.
Posted by dirkson 4 years ago
Though I don't have time to do it, I think a reasonable counter argument could be made by filling in reasonable growth rates for alien civilizations, and positing that they'd most likely construct works visible from large distances.

That said, I've also heard of near black body planets, which I find suspicious. (Besides the fact that I just, y'know, agree with pro :D )

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Vote Placed by Ore_Ele 4 years ago
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Reasons for voting decision: Pro should have had an easy argument, however, she address almost nothing in her 2nd round and dropped her 3rd round.
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Vote Placed by Ron-Paul 4 years ago
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