U.S. CitiesCity-Data Forum Index
Covid-19 Information Page
Go Back   City-Data Forum > General Forums > Science and Technology
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
Reply Start New Thread
 
Old 06-21-2020, 07:20 PM
 
Location: Harrisburg, PA
600 posts, read 378,654 times
Reputation: 605

Advertisements

What if Earth-like planets aren't rare, but life itself is? Like there's a bunch of rocky planets with sandy land and salty oceans, but no life whatsoever. I mean, we can't even explain how life started on earth... Lightning bolt struck a puddle of acids?, volcanic eruption released a complex chemical substance?, or even divine/spiritual intervention, or maybe aliens?

Anyway, the purpose of this thread is not to necessarily debate our source, but rather: what if intelligent life is so rare (or almost impossible) to find in the universe not because the conditions don't exist, but simply due to some extremely rare process or energy release that happened on Earth to kick-it-off. Maybe there's plenty of earth-like planets out there, but we just happened to be extremely lucky?

Is this a possible/valid reason why we haven't found intelligent life yet?
Reply With Quote Quick reply to this message

 
Old 06-21-2020, 10:53 PM
 
3,794 posts, read 1,444,629 times
Reputation: 2775
Earth like planets are already thought to be rather common. Some estimates suggest that there are 40 billion such planets in the Milky Way alone.

It also goes without saying, that not all rocky planets are Earth like and being in the Goldilocks zone of the star they orbit doesn't guarantee that lifeforms will develop. This zone just defines the area where liquid water can be found on the surface. There's also the issue that exoplanets can be wrongly classified and what we think is a rocky world may end up being a gas giant.

We can't determine how common or rare life is since we only have a single data point to work with, which is the Earth. It could be plentiful. It could also be that we truly are alone. At the end of the day, we don't know the odds and likely never will.
Reply With Quote Quick reply to this message
 
Old 06-22-2020, 04:36 AM
 
Location: The Driftless Area, WI
4,057 posts, read 1,582,622 times
Reputation: 9381
Our planet is thought to be 4.5 Billion yrs old, and we have evidence that life is at least 3.5Billion yrs old here, ie- it was "easy" to get life started.


Let's guess that that one in 1000 stars have planets (that's 10^-3) and let's say one in 1000 of those have available water (water is a unique solvent- dipolar and expands when frozen, so life can easily still metabolize actively "under the ice" when the atmosphere is cold; not necessary for alien life to exist, but makes it more likely). So we're saying 1 in a million stars have a planet favorable to life (10^-6)...Now let's tie one hand behind our backs and say only 1 in a billion has favorable conditions (10^-9).


Our galaxy has 10^12 stars, so if only one in a billion have life, then there's 1000 stars with life in just our galaxy alone....There's 10^12 galaxies in The Universe, so there's a million planets with life altogether.


So, even if The Force ain't with you, The Numbers are.
Reply With Quote Quick reply to this message
 
Old 06-22-2020, 07:22 PM
 
3,794 posts, read 1,444,629 times
Reputation: 2775
Quote:
Originally Posted by guidoLaMoto View Post
Our planet is thought to be 4.5 Billion yrs old, and we have evidence that life is at least 3.5Billion yrs old here, ie- it was "easy" to get life started.
True, but that’s just the Earth. It doesn’t support any other evidence.

Quote:
Let's guess that that one in 1000 stars have planets (that's 10^-3) and let's say one in 1000 of those have available water (water is a unique solvent- dipolar and expands when frozen, so life can easily still metabolize actively "under the ice" when the atmosphere is cold; not necessary for alien life to exist, but makes it more likely). So we're saying 1 in a million stars have a planet favorable to life (10^-6)...Now let's tie one hand behind our backs and say only 1 in a billion has favorable conditions (10^-9).
From all the data we’ve gathered, planets are a lot more common than that. It appears that most stars due in fact have them because they form naturally from the protoplanetary disc that orbits the star.

Quote:
Our galaxy has 10^12 stars, so if only one in a billion have life, then there's 1000 stars with life in just our galaxy alone....There's 10^12 galaxies in The Universe, so there's a million planets with life altogether.


So, even if The Force ain't with you, The Numbers are.
The numbers are with you only to the extent that there’s a lot of stuff out there, and by that I mean stars and planets. Everything beyond that falls under the realm of speculation as we only have a single data point to work with, which is the Earth.
Any hypothetical number you can come up to discuss the odds of life is just that, purely subjective.
What if the odds of life happening are 1 in a googol ( that’s 10^100 btw)?
Reply With Quote Quick reply to this message
 
Old 06-22-2020, 08:42 PM
 
4,046 posts, read 4,449,787 times
Reputation: 4823
True- that's why when people get worked up over petty things, I roll my eyes. This notion of "self-importance" is ridiculous. We all matter, and the fact that our existence is so precious reminds me of the little things in life that matter most, as life is short.
Reply With Quote Quick reply to this message
 
Old 06-24-2020, 06:30 PM
 
Location: The Driftless Area, WI
4,057 posts, read 1,582,622 times
Reputation: 9381
Quote:
Originally Posted by Milky Way Resident View Post
True, but that’s just the Earth. It doesn’t support any other evidence.

Hence the qualifier "Earth-like." If life came easily here, no reason it shouldn't be just as easy on other Earth-like planets.


You're right-- I purposely used low numbers to show that there are still a whole lot of chances for life to develop out there. In reality, the odds are much better....so much better that it's more than a probability. It's a certainty.....


Of course, a million planets with life spread out over the whole Universe (in space AND time) is a pretty dilute solution. The odds of any two having advanced civilizations contemporaneously and coming in contact with each other is pretty remote.


Self organizing systems are rather common in Nature because the Universe is run by probabilities, and the odds of things settling into minimum energy states are the most probable. In principle, the only difference between a spherical oil droplet in water and a living cell is a matter of the complexity of the two systems.


Even Darwin's "survival of the fittest" is really just a special application of the general rule that "things exist in their most likely state."
Reply With Quote Quick reply to this message
 
Old 06-30-2020, 09:06 PM
 
Location: Mars City
5,909 posts, read 2,788,959 times
Reputation: 8846
What difference does it make if we'll never know one way or the other? We can speculate till we're blue in the face, and it one make squat of a difference.

We could apply thought and action into something useful and tangible on Earth though (hint hint).
Reply With Quote Quick reply to this message
 
Old 07-01-2020, 05:14 PM
 
Location: Seattle
6,115 posts, read 1,440,286 times
Reputation: 5365
Well the chemistry needed to create life is extremely common; we find it in comets, molecular clouds, and around other stars. Was the pre-biotic Earth particularly unique? I don't think so. It is hypothesized that both Venus and Mars also sustained oceans, and thus potentially life-forming chemistry. Hence the required conditions aren't that uncommon. Life formed very early on in Earth's history, so it couldn't have been that unlikely. I think life is very common, but technology-using intelligent life is rare.
Reply With Quote Quick reply to this message
 
Old 07-02-2020, 03:17 PM
 
5,406 posts, read 8,469,393 times
Reputation: 3455
Quote:
Originally Posted by Thoreau424 View Post
What difference does it make if we'll never know one way or the other? We can speculate till we're blue in the face, and it one make squat of a difference.

We could apply thought and action into something useful and tangible on Earth though (hint hint).
Says the person who identifies his location as... (ahem) Mars City?
While you certainly have a good point, that doesn't mean speculation about life elsewhere in the universe is a meaningless thing to do regardless of whether or not it makes a squat of difference. It's thinking outside of the box that might directly or indirectly make a contribution to make things more useful here on Earth.
Reply With Quote Quick reply to this message
 
Old 07-02-2020, 03:33 PM
 
1,170 posts, read 232,908 times
Reputation: 1948
Until we develop faster than light way to transverse the galaxy, we wont know. Unless some bright boy or girl figures out way to detect it with telescope.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply

Quick Reply
Message:

Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Science and Technology
Follow City-Data.com founder on our Forum or

All times are GMT -6.

© 2005-2020, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Contact Us - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37 - Top