News Proof of Aliens Could Come Within 25 Years, Scientist Says

[IronRain]

Why is NASA always looking for planets with water and normal temperatures. They always say that if there's not one of those 2 ''ingredients'' on another planet, there can't live anything. But what if the Aliens are build to the (for us) extreme condition of another planet?

 

[johan]

Why is NASA always looking for planets with water and normal temperatures. They always say that if there's not one of those 2 ''ingredients'' on another planet, there can't live anything. But what if the Aliens are build to the (for us) extreme condition of another planet?

Like bacteria surviving in impossible circumstances in places on Earth, or for that matter, Polar Bears surviving impossible cold (granted they all have water though...)

 

[Urwumpe]

Like bacteria surviving in impossible circumstances in places on Earth, or for that matter, Polar Bears surviving impossible cold (granted they all have water though...)

That is an error: Nobody said in advance that it is impossible for bacteria to exist, for example, in black smokers. Or for polar bears to survive cold.

They are all extreme animals, but still not beyond biology.

The existence of water and ozone has actually some good reasons: Water is part of many chemical reactions, and you don't have infinitely many chemical reactions that could sustain life. It might be different life, but not extremely different life. Ozone can only exist if enough O2 is produced on that planet. Oxygen is again needed for life because the alternative substances are too rare in the universe (Since they are only produced in the core of very large stars).

Impossible is a dangerous term, but not all is possible or remotely likely. If you would have a planet with 10% Flour in it, life might use that as substitute for oxygen, but that is not very likely, since Flour can only be controlled in chemical reactions in a very tiny temperature range.

 

[garyw]

Why is NASA always looking for planets with water and normal temperatures. They always say that if there's not one of those 2 ''ingredients'' on another planet, there can't live anything. But what if the Aliens are build to the (for us) extreme condition of another planet?

Whilst Urwumpe is spot on the implications of an Earth like planet in another solar system cannot be understated. If we had proof one tomorrow it may well spur some countries into stepping up space activities. Funding for things like exoplanet hunting would certainly get a boost.

The cynical side of me says it is all about the funding.

 

[T.Neo]

Exactly. Not only do chemicals like water, carbon or nitrogen seem optimal for supporting the chemical reactions in life, but they're very common in the universe compared to other proposed chemicals.

Thus it is important to search for planets within the temperature ranges in which water is liquid, and familiar chemical reactions can occur. A planet may be at 60 degrees, and be suitable for life.

Though I think there is a possibility of complex organisms existing in an atmosphere with little to no free oxygen. I believe there was a story recently about animals living without oxygen in cold seeps on the mediterranean seafloor, or something to that effect, though unfortunately I can't provide a link.

But just because life is built of the same basic building blocks does not mean there is potential for wildly different biochemistries. It will probably be the norm, rather than the exception, for alien life to be composed of many weird and wonderful never seen before molecules.

 

[garyw]

Another minor detail, is that it's usually referred to as a "sapient" life, denoting knowledge and intelligence (Homo Sapiens etc). Sentience is the ability to feel and percieve, which organisms far simpler than humans posess.

I know this. I'm specifically referring to SENTIENT life.

SAPIENT life can be detected if the planet transists its star enough to get a reading on the atmospheric content of the atmosphere. Much like we can detect some rather interesting chemical reactions on Titan.

 

[T.Neo]

I know this. I'm specifically referring to SENTIENT life.

So you're saying we're the first sentient life in our corner of the Galaxy when we aren't even the first on our own planet? :huh:

SAPIENT life can be detected if the planet transists its star enough to get a reading on the atmospheric content of the atmosphere. Much like we can detect some rather interesting chemical reactions on Titan.

How would you have been able to detect cro-magnon peoples by doing a spectral analysis of Earth's atmosphere?

And if you did manage to do a spectral analysis the atmosphere of an alien planet, what's to say that the origin of some of the phenomena is an intelligent organism? For example Earth has an increasing amount of CO2 in the atmosphere due to human activity, but we've had far higher levels of it in the past due to things like volcanic activity.

 

[garyw]

And if you did manage to do a spectral analysis the atmosphere of an alien planet, what's to say that the origin of some of the phenomena is an intelligent organism? For example Earth has an increasing amount of CO2 in the atmosphere due to human activity, but we've had far higher levels of it in the past due to things like volcanic activity.

You wouldn't have a positive indication but you'd be able to detect life due to changes in the atmospheric contents - that's it.

Gives you an interesting target to speculate about.

 

[T.Neo]

Of course you'd be able to detect life, because it'd be doing strange stuff to the atmosphere- the large amount of free oxygen in our atmosphere is an example, as is a small amount of biogenic methane. If Earth didn't have life, it'd probably have an atmosphere that would look like an interesting mix of Venus and Titan.

You wouldn't have any way of figuring out what life exists on the planet though. It might be nothing more than bacterial slime.

 

[jedidia]

Exactly. Not only do chemicals like water, carbon or nitrogen seem optimal for supporting the chemical reactions in life, but they're very common in the universe compared to other proposed chemicals.

what about Fluorine? as far as I understand it (which might as well be wrong), fluorine in small amounts is a neccessary ingrediant for the developement of carbon-based life. Yet it seems to be very rare, because it's only produced in systems with a white dwarf companion.

 

[T.Neo]

I don't see how fluorine is absolutely essential for carbon based life. Life on Earth does use it, but we use it in very small amounts.

It isn't exactly the most common element, but I don't remember hearing that it is only produced in systems with a white dwarf companion. It clearly exists in our system, but we have no such companion.

 

[jedidia]

No, but we got one in the vicinity. I read that part with the Fluorine somewhere in a rather old article (12 years or so...?) about the rare earth hypothesis, so I don't really know wheather or not this has any truth, I was more posting a question than a statement.

 

[RisingFury]

what about Fluorine? as far as I understand it (which might as well be wrong), fluorine in small amounts is a neccessary ingrediant for the developement of carbon-based life. Yet it seems to be very rare, because it's only produced in systems with a white dwarf companion.

Most Fluorine is actually created in a supernova...

A white dwarf is the final evolutionary state of a star that isn't massive enough to supernova. I don't see why you'd need a white dwarf companion to produce Fluoride...

No, but we got one in the vicinity.

Even if a white dwarf companion would be required to produce Fluoride, it's proximity to Earth wouldn't matter. The material that created our solar system was enriched when other stars died in a supernova.

 

[T.Neo]

Well, the wiki article on Carbon-based life doesn't mention any intrinsic need for fluorine, and the biological role section of Fluorine mostly discusses it's role in plant defences and preventing tooth decay.

What white dwarf are you exactly referring to? Van Maanen's star? Sirius b? I think that due to proper motion they probably were not in our vicinity back when the Earth was being formed.

 

[jedidia]

I don't see why you'd need a white dwarf companion to produce Fluoride...

If I remember correctly, there was some babble about a white dwarf catching expelled gases from a red giant and producing fluorine, and that this would be the only known way fluorine could be naturally produced. Probably nonsense, then, I gather.

What white dwarf are you exactly referring to? Van Maanen's star? Sirius b? I think that due to proper motion they probably were not in our vicinity back when the Earth was being formed.

apologies, misformulation. If I remember right they said that there was a red giant/ white dwarf binary pair in the vicinity during the formation of the earth. They didn't say which one they were refering to, and they didn't tell if it was still around either...

 

[T.Neo]

Yeah, it sounds like nonsense to me...

 

[RisingFury]

If I remember correctly, there was some babble about a white dwarf catching expelled gases from a red giant and producing fluorine, and that this would be the only known way fluorine could be naturally produced. Probably nonsense, then, I gather.

I think you're misremembering here...

A possible way to make a star go supernova is if it has a companion and is "stealing" it's gas. The companion will be stripped down to a white dwarf because only it's core will remain and the heavier star may accumulate enough mass to later supernova.