Aliens, Exist or Dont

[adsii1970]

3 minutes ago, magnemoe said:

Then we are able to search for oxygen and methane at earth sized planets we will get an good answers about how common life is 
 

That's assuming it's life similar to life on Earth based on carbon and methane is the direct process of decomposition.

A life form based on silicon, for example, may breathe in nitrogen and when it decomposes, produce some sort of ammonia compound...

[kerbiloid]

48 minutes ago, adsii1970 said:

A life form based on silicon, for example, may breathe in nitrogen

You make me worry about my computer CPU. It's surrounded by the aggressive 78%-nitrogen atmosphere...

As melting point of the silicon nitride is 1900°C, probably their toilets are polished to shine by the sand blasting.

Edited March 18, 2017 by kerbiloid

[DoctorDavinci]

I'll just leave this here ... The playlist provides an interesting viewpoint on this subject

 

[adsii1970]

I'll also share an alien video:

 

[Vinhero100]

I'm %99.9999999999 percent sure that there is alien life (microbes). But if there is intelligent life lurking in deep space, I would be surprised. 

[magnemoe]

On 18.3.2017 at 5:39 PM, adsii1970 said:

That's assuming it's life similar to life on Earth based on carbon and methane is the direct process of decomposition.

A life form based on silicon, for example, may breathe in nitrogen and when it decomposes, produce some sort of ammonia compound...

No it does not detect non carbon types of life, neither life without photosynthesis and it has to run for some time too. 
But then we get an list of earth like planets and how many of them have oxygen we have pretty solid data. 
 

[Firemetal]

Yes probably but I doubt they are what we think they are. There are billions of planets. And billions of habitable planets as well. And I assume some of those have life on them.

Fire

[Urses]

Yes they are there.

And no i dont like to see them tommorow. 

Why? Its like Hawkings said. If they come we are gone...

If Terranier(?) have some colonies in around like 50-100ly there is a possibility to Meet and converse and not Meet and Genozide. 

[hugix]

Can't remember who'se quote it is but. 

Either we are all alone in the universe or we aren't. Both answers are equally scary.

 

 

If there is alien life, would we ever find it and classify it as "living". Just look at Earth. There are so many differences between life on Earth. From humans to trees, from trees to bacteria. Suppose we find life on Europa for example, would we even recognize it as life? 

[kerbiloid]

Happily, interstellar distances are enough huge to make an expansion useless and to frozen any originally hot nature.

Until somebody can send a battleship to another habitable star system, he/she/it would run out of rage, finish the overpopulation growth, make recyclable resouirce loop and become an old scrooge living in a overprotected asterioid belt near its native planet. Living 95% of its life in virtual/augmented reality.
Incommunicative (as it knows almost all it needs) and thus invisible for SETI, not agressive (as doesn't need more land to breed around, but can lose everything), not very curious (see p.1.), busy with suburban areas adaptations (i.e. building transit and communication outposts in other solar systems) and with mating the physics and mathematics to get a god-like power.

Almost necessary - a "hivemind", as its population will be decreasing, while every person getting 95% "standardized" using its hivenet.
So, any its person would become just a reflection of the hivemind..

(That's btw means that any individual "ET" would not be important, as it's just a reduced mind clone. It can produce them as many as required, and send in one-way missions as expendables.
So, not much sense in capturing and interrogating one.)

Probably, almost all interstellar contacts look like a meeting of Gandalf and Dumbledore on a desert island amid the ocean.
A five o'clock discussion about nothing between two cheaters with guns.

Edited March 20, 2017 by kerbiloid

[Bill Phil]

It's very hard to be invisible with a big enough civ. Waste heat gives you away.

[Urses]

5 minutes ago, Bill Phil said:

Waste heat gives you away.

I think the Communication polutuon is more of a Probleme here?

[kerbiloid]

40 minutes ago, Bill Phil said:

It's very hard to be invisible with a big enough civ. Waste heat gives you away.

While you expand, build a lot and communicate with radiowaves.

When you already leave in an ivory tower, not expanding, counting every joule spent for communication and lighting, endlessly recycling every piece of matter in your room (making same atoms to be either a snack, or a sock, throwing it in to the utilizer), not much energy you need, not much energy you waste. 
Of course, a Gandalf civ always can detect Dumbledore civ in their telescopes. But we, troglodytes, no.

Edited March 20, 2017 by kerbiloid

[WinkAllKerb'']

51 minutes ago, Bill Phil said:

It's very hard to be invisible with a big enough civ. Waste heat gives you away.

so primitve soup civilisation is less valuable than the current human model ... ? ... not sure whose primitive ... it can be at a previous stage at a later stage ...

the matter with human, they think they are the best and what's different from them is of no interest ... seriously ... if alien more evolved whatever the way scheme think like that ... gonna bode well ...

also the concept of civilisation ... well to much binded to our own evolve since the primitiv soup and the very local and specific solar system conditions  ... some others scheme/variation may exist ...

*grumpf* /rant

Edited March 20, 2017 by WinkAllKerb''

[KerikBalm]

On 3/17/2017 at 0:46 AM, Gaarst said:

Aliens don't exist until proven otherwise. That's how science works.

Edit: I personally think it is possible they exist, but opinion != fact

No, science makes no claims one way or the other about stuff with no evidence.

We can speak about probabilities, and there is a very high probability that life exists somewhere else in the universe.

Titan? Europa? intelligent life? not so sure.

Aliens that have visited Earth - very unlikely IMO

[Green Baron]

1 hour ago, KerikBalm said:

 

We can speak about probabilities,

In that i differ, at least concerning complex life (multicellular, food chain, biocenosis, this sort of things). Probabilities need a data base and we only have one single sample. Also they need constraints to work with and we (at least i ... :-)) don't know about any constraints on distant planets except estimated temperature. And we call that "habitable zone". We see in our system how deceiving that can be: Venus is on the inner edge of the "habitable zone". Were it near Trappist or Proxima C. it would be crowded with aliens . But in reality it is not really known as a cozy place.

But, really, i don't know.

[KerikBalm]

well, i said "speak"... but yes its intentionally hazy.

We know life must obey thermodynamics, and we know the elements and basic chemistry are the same everywhere.

https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry

We know water and carbon based life works... 

Silicon is probably not going to work... carbon seems like a very solid choice... but the solvent seems much more open to other possibilities.

We don't know if a non-polar solvant could work, or if ammonia could work...

We can make rough estimates about the possibility of a habitable environment for water based life on a planet.

A planet where life could survive is not necessarily the same as a planet where life could start, but we can only make the vaguest of statements about this probability (0<x < or = 100).

If we find that Europa and Enceledus are sterile, but otherwise habitable then we know x is strictly less than 100.

We don't know if Methane solvents could work.

Even despite that, we know Earth's conditions work, and we have fairly good estimates for the number of stars similar to ours in the observable universe. Even using very conservative estimates, there should be a great deal of planets with similar physical conditions to Earth. Physics and chemistry being the same everywhere, the probability that another planet exists with conditions similar to ours that has life as well is very high.

What percent of stars have life on some body orbiting them.... that is basically a complete guess - but the question of if there is another world with life in the universe: just using our very limited observations that Earth's conditions can produce life is enough to conclude that there is a high probability of life elsewhere in the universe.

 

But.... a planet with microbes in another galaxy doesn't really matter from a practical perspective, does it? Practically speaking, the question is if any other planets or moons in our solar system (and perhaps nearby star systems) have microbes, and if there is another form of "intelligent" life in our galaxy (in this sense, intelligent enough for spaceflight or at least radio communication)

And for that question... we severely lack data.

[Matuchkin]

On 16/03/2017 at 7:46 PM, Gaarst said:

Aliens don't exist until proven otherwise. That's how science works.

Edit: I personally think it is possible they exist, but opinion != fact

Granted, their existence are not proven, but their probability is pretty much 100%. I would say that, including in the areas past the Hubble limit, there would be sextillions, septillions of stars, and we already found over 1000 planets around stars in our tiny sector of our tiny galaxy, of which over 500 are habitable. Come on, if planets are that common, they obviously outnumber stars by a very large factor. To believe that habitable planets do not exist is a bit unscientific at this point.

[kerbiloid]

On other hand. If a civilization has reached a technological level that allows it to build species from the known DNA sequence.
Why should it bother with a more primitive life search and preservation?
Why should it hold its breathe watching one more primitive neglibile attempt of moleculas to gather together?
Don't you mill the raw stones into dust and form concrete blocks from it, instead of living in a cave?

 

Probably, on its firsts steps in space the civ would gather biosamples, kiss them, study and keep in scientific treasuries, protecting the planet "inhabited" with bacteria and fungi.

Getting more aged and experienced they will just gather new samples, sequence their DNA and store in computers as just one more random life appearance.

Getting even more aged they will find it stupid to store more and more random numbers rather than just generate them on demand. They will just ignore that "living beings".
They can any time create and breed any optimized lifeform they had constructed.

And at last they will treat any unplanned life as a contamination and sterilize the livable planets without bothering to study them before setting their own biosphere.

DNA is just a sequence of 4 (and a half) nucleobases: A,G,C,T,U (and T is an ill U).
All of them are just a polluted Pyrimidine molecula. Why should they see some magic here?

Edited March 27, 2017 by kerbiloid

[KerikBalm]

1 hour ago, kerbiloid said:

Getting more aged and experienced they will just gather new samples, sequence their DNA and store in computers as just one more random life appearance.

Who says the life will use DNA? One of the best theories for life on Earth postulates that there was a time when life lacked DNA completely. Of course, that was RNA, but who says the alien life will have nucleic acid as its hereditary material at all? We wouldn't expect life on Titan to be using such molecules in a hydrocarbon solvent.

Quote

Getting even more aged they will find it stupid to store more and more random numbers rather than just generate them on demand. They will just ignore that "living beings".
They can any time create and breed any optimized lifeform they had constructed.

And at last they will treat any unplanned life as a contamination and sterilize the livable planets without bothering to study them before setting their own biosphere.

Still, its a planet scale bioreactor that would have been operating for billions of years. They would surely see value in looking at what it produced. Their study may be faster and more efficient though.

Quote

DNA is just a sequence of 4 (and a half) nucleobases: A,G,C,T,U (and T is an ill U).
All of them are just a polluted Pyrimidine molecula. Why should they see some magic here?

DNA, as life uses it, is just ACTG. T is not an "ill U". The U only (naturally) occurs in RNA, and could be thought of as an "ill T" because it binds with more than just A.

There is nothing limiting DNA to just those 4 bases, and additional bases have been made synthetically.

Lastly, only 3 of them are Pyrimidines (A, T/U), the other 2 are purines (C,G).

[kerbiloid]

2 hours ago, KerikBalm said:

Who says the life will use DNA? One of the best theories for life on Earth postulates that there was a time when life lacked DNA completely. Of course, that was RNA

DNA/RNA sophistics. 
Of course, I meant (D/R)NA as a whole thing. DNA doesn't work without RNA, and has appeared from it.

2 hours ago, KerikBalm said:

We wouldn't expect life on Titan to be using such molecules in a hydrocarbon solvent.

Titan has life?

2 hours ago, KerikBalm said:

Lastly, only 3 of them are Pyrimidines (A, T/U), the other 2 are purines (C,G).

Quote

A purine is a heterocyclic aromatic organic compound that consists of a pyrimidine ring fused to an imidazole ring.

Grandpa. Pa's pa.

2 hours ago, KerikBalm said:

A, but who says the alien life will have nucleic acid as its hereditary material at all?

 

2 hours ago, KerikBalm said:

DNA, as life uses it, is just ACTG. T is not an "ill U". The U only (naturally) occurs in RNA, and could be thought of as an "ill T" because it binds with more than just A.

There is nothing limiting DNA to just those 4 bases, and additional bases have been made synthetically.

Let's have a look.
 

Spoiler

Benzene.
(CH)6. 

Not much things can be more simple and common than it. And of course, it's everywhere where any hydrocarbons is. It's one of the most common moleculas in the Universe.

Pyrimidine.
1,3-diazine.
(CH)4N2.

Just a benzene with two Ns instead of two (CH). A very primitive and common thing.

Uracil aka U.
2,4-dioxopyrimidine.
(CH)2(NH)2(CO)2. 

Pyrimidine with two Os attached to two Cs instead of Hs and both Ns having attached H.

Thymine aka T.
5-methyluracil
(CH)2(NH)2(CO)2(CH2).

Uracil with CH2 group attached to one of Os. 
Just a methylated uracil, nothing more. That's what I meant as "an ill uracil" sounds poetic btw. They take the same place in DNA/RNA.

Cytosine aka C.
4-amino-2-oxo-pyrimidine
(CH)2(NH)(CO)C(NH2)N. 

Pyrimidine with NH2 attached to one of C, O - to another C, H attached to one of two Ns.
Or, in other words, uracil with NH2 replacing one of Os and one lost H.

Purine.
imidazo[4,5-d]pyrimidine
(CH)2N2-C2-(CH)N(NH).

Pyrimidine with (CH)N(NH) ring (a beheaded imidazole) attached to a "free side".

Adenine aka A.
6-aminopurine

Just a purine (i.e. a modded pyrimidine) with attached NH2.

Guanine aka G.

Look at its molecula and you see a Cytosine with attached (imidazo-)group. I.e. a purine-based equivalent of cytosine.

So, as you can see, if avoid magically sounding names, all this stuff is made of most cheap and common pieces of organic (and nitrogenic) junk, and has very Very simple structure.

Of course, there are other variants to pollute the diazine molecula with ammonia and methylic wastes, and sure a DNA/RNA can survive if add/replace some of them instead of AGCTU.
(Though they had all chances on the Earth, as AGCTU had, but not survived IRL, giving us a hint not to bet much money on the alternatives).
But all these possible combinations are simpliest of simple organic entities, and unlikely you would have thousand of their combinations able to endlessly reproduce in the cruel wild world.
Maybe you can replace some NH2 or add one more CH2, but this wouldn't cause combinatoric explosion.

So, yes, a super-civ should use a byte rather than two bits to describe a (...)NA node for their artificial pets genetic code. 
But sure they have enough large HDD.
 

2 hours ago, KerikBalm said:

Still, its a planet scale bioreactor that would have been operating for billions of years. They would surely see value in looking at what it produced. Their study may be faster and more efficient though.

Earth bioreactor operates for ~4 bln years. Most of this time it procrastinated with unicellulars and other junk. 
Something practically significant appeared just about 300 mln years ago, while something enough dense and compact to deal with it personally - just several tens millions ago. 
98% of the Earth life existance this "life" was clots of slime in dirty pool. And that's in ideal for organic life evolution conditions.

There should be many planets with algae, bacteria and mildew. 
First hundred of them the super-civ would enthusiastically listing them, matching every junkazoid with its (...)NA code. And trying to reproduce and optimize.

Did you ever play Spore or No Man's Sky? That's exactly how should the super-civ bilogists feel studying 101st planet.
After 200th "living" planet they should evade from dull and useless field trips at any cost, quckly synthesizing random creatures in their lab vats as anyway nobody cares and see a difference.

Simultaneously, no doubt, they will do their best with the Earth creatures (including human bodies) re-engineering, making such perfect super-beasts that they would just need no more wildlings to study something new.

And you can watch Prometeus movie to see what they be. Alien Engineers don't need inferior beings DNA, they make themselves what they want.
 

Edited March 27, 2017 by kerbiloid

[Urses]

On 18.3.2017 at 5:39 PM, adsii1970 said:

That's assuming it's life similar to life on Earth based on carbon and methane is the direct process of decomposition.

A life form based on silicon, for example, may breathe in nitrogen and when it decomposes, produce some sort of ammonia compound...

It would be a realy smelly world... at least for us.

But you don't realy have to go so far to find unconventional liveforms. Look at a undersee vulkans and the hypotherm lifeforms there. AFIK they consume sulfids as energy support?

[kerbiloid]

21 minutes ago, Urses said:

Look at a undersee vulkans and the hypotherm lifeforms there. AFIK they consume sulfids as energy support?

Are they originally sulfur-consuming or former oxygen-breathers having to replace O with S?

[Urses]

17 minutes ago, kerbiloid said:

Are they originally sulfur-consuming or former oxygen-breathers having to replace O with S?

Sorry is like 5-10 years ago, so i dont realy recall but as far i remember they are anaerob(oxigen kills them) and need temperatures higher than 70°C to exist.

This said there found some anaerob bakterias with 200°C+ too.

I have to search the Source if somebody is interested, but need some legwork.

[kerbiloid]

I took a look, all of them are prokaryotes. So, probably they were sulfur-based all the time, from the beginning.