Drake Equation on Alien Life Has Been Revised

[Frank Merton]

You can't imagine an oxidized planet surface? Who said anything about free hydrogen?

I'm always amazed when people say that extraterrestrial life is the simplest explanation for something.

I can't imagine a primitive atmosphere without hydrogen, unless all the gas had been blown away, and then there would be no oxygen either (unless replaced somehow. What is this about an oxidized surface -- we are talking about atmospheres. That is the point about free oxygen in the atmosphere -- it leads to oxidation -- generally of the surface hence removing it from the atmosphere.

The only way to oxidize an atmosphere that I have ever heard of and keep it oxidized is life. Let me put it this way -- if they ever confirm significant free oxygen in an atmosphere, they are going to get very excited and that planet is going to get a lot of attention.

[ambelamba]

One thing that Drake Equation ignores is the SIZE of a civilization. Of course, it's pretty impossible to even guess on that issue.

[psyche101]

Yes it smells with the idea that man is master of the universe and only he decides how many aliens there are out there.

LOL, that well illustrates that you do not understand the Drake Equation, nor math!

It is not a fallback position of skeptics as was earlier suggested, that would not be in line with skeptical thinking, it's more of an argument of probabilities, something a bit like Schrodinger's Cat explains all states of a particle exist until examined, the Drake Equation examines statistical probabilities and outlines basic required components to be considered with regards to radio communications and what should be detectable. As it uses unknown values and estimates, it is an illustration, not intended to be considered fact.

For instance, what is the value of f_i f_e f_c and L in the Drake Equation?

Resolving the equation is not the point of it, contemplating it is.

Your smell needs readjusting.

[psyche101]

It is of course possible that we are the only intelligent life in the universe. We don't have good information for all the known variables that are believed to determine the odds for the existence of such life.

Even so, it is worth considering a recurring problem in the history of human knowledge. Whenever we have supposed ourselves to be uniquely situated in some way, further learning has eventually refuted such ideas.

The Earth was once considered to be at the center of the physical universe. We saw this give way to a Sun centered universe a few centuries ago.

Once it was understood that the Milky Way was a huge collection of stars like our own Sun, it was imagined that we were at the center of it, and that our galaxy was unique in the universe. We eventually realized that we are far from being at the center of our galaxy, and that our galaxy was one of billions, strewn throughout an immense expanse of space.

It was once thought that planets were the result of exceptional cosmic accidents and must be extremely rare. We now see that planets are common, wherever we care to look.

Again and again, the assumption that we enjoy unique or exceptional circumstances in the universe has come to nothing. If I am asked now to believe that the conditions necessary for intelligent life to arise are unique to our planet, or so exceptional as to effectively isolate us from whatever other intelligent life may exist, at some vast distance, I must respectfully decline.

In all those cases, a small scientific contingent battled long and hard through adverse conditions to finally be recognised.

Like critical thinkers wading through endless reams of belief today. One cannot propose ET is not an answer any longer, one is expected to prove a negative. I think you have your analogy the wrong way around, and did not realise it.

We won't be asking this question forever, it might even be resolved in our lifetimes yet. Atmospheric compositions are likely to give us the rub here.

[mcrom901]

[/size]

Only because these incorrect assumptions were based on incomplete or false information.

We now know a lot more about our planet and the life on it and all of it strongly suggests that life was the result of a series of unique and exceptional circumstances. The more we learn about life on Earth, the less likely it appears that something like it would happen again.

why is that?

[Space Commander Travis]

i love the Drake Equation and discussion about it, since it's one big assumption based on a whole string of assumptions, and yet people build the most extraordinarily enormous assumptions (such as the one above) based on it. And people base their enormous castles of assumption on it as if it's irrefutable scientific fact.

[mcrom901]

i love the Drake Equation and discussion about it, since it's one big assumption based on a whole string of assumptions, and yet people build the most extraordinarily enormous assumptions (such as the one above) based on it. And people base their enormous castles of assumption on it as if it's irrefutable scientific fact.

are you referring to my post?

[S2F]

Drake's Equation! Fermi's Paradox! The curse of Klass! Schrodinger's dead/alive cat!

Godammit! I need a drink!

[psyche101]

Looks like Canadian Club!!

Pour another for me mate! Ambrosia of the God's that stuff.

are you referring to my post?

Hard to say, there are a number of posts "above" isn't there.

Edited September 18, 2013 by psyche101

[Space Commander Travis]

are you referring to my post?

No, i meant the one you quoted, well, not just that, but all the assumptions that people make as shown in this thread.

[Asadora]

I found this after reading more about the Drake Equation:

http://www.as.utexas.edu/astronomy/education/drake/drake.html

It's a Drake Equation Calculator, which is cool in itself; however, I am not sure if scientists have the numbers to put into the boxes on that page. I certainly don't. I think that the only numbers we have (so far) would be to fill the first box of that calculator? We haven't come anywhere close enough to determine any of the other numbers needed... maybe... I am not sure.

Anyway, it's a cool thing to fiddle with for all you numbers people!

Kind Regards

[Space Commander Travis]

From what that chap from SETI was saying, it seems to be thought quite likely that 70-80% of Stars would have Planets, but everything from the third box onwards is just guesswork based on our knowledge of this one solar system, isn't it. our solar system may be typical, in which case perhaps there might be one planet per system that ticks all those boxes, or it might be untypical or atypical, and Life might be more common than it is in this system or it may be less common. Really all we can do is guess from what we know, and that's not nearly enough to be able to make anything like an adequate guess.

[Asadora]

From what that chap from SETI was saying, it seems to be thought quite likely that 70-80% of Stars would have Planets, but everything from the third box onwards is just guesswork based on our knowledge of this one solar system, isn't it. our solar system may be typical, in which case perhaps there might be one planet per system that ticks all those boxes, or it might be untypical or atypical, and Life might be more common than it is in this system or it may be less common. Really all we can do is guess from what we know, and that's not nearly enough to be able to make anything like an adequate guess.

You know what I find absolutely interesting? What exactly -is- typical (not based on science already known), but what is universally typical? Do we know that?I don't think we do. And who knows, the universal typical might very well be untypical enough to be considered atypical yet that in itself could be typical?

Great times to be alive!

Edited to add something I forgot to type.

Edited September 18, 2013 by Asadora

[scowl]

why is that?

Because the more we discover about early life, the more complicated and fragile we discover it was. The conditions for it happening get increasingly restrictive and the conditions for it surviving for long periods of time get increasingly unlikely. We haven't discovered much that has made life appear more likely to happen.

[mcrom901]

Hard to say, there are a number of posts "above" isn't there.

yeps, a bit of paranoia from me there...

No, i meant the one you quoted, well, not just that, but all the assumptions that people make as shown in this thread.

couldn't agree more and that's what ticks me off; certainty...

Because the more we discover about early life, the more complicated and fragile we discover it was.

which specific hypothesis are you referring to re the origins?

The conditions for it happening get increasingly restrictive and the conditions for it surviving for long periods of time get increasingly unlikely.

based on what model? earth?

We haven't discovered much that has made life appear more likely to happen.

is the curiosity rover able to dig deep in the martian soil to search for potential methane producing bacteria? that's only in our own solar system.... and then there's the unobservable observable universe...

[scowl]

which specific hypothesis are you referring to re the origins?

All that I have read. Name one.

based on what model? earth?

Do you have any other models?

is the curiosity rover able to dig deep in the martian soil to search for potential methane producing bacteria?

Bacteria in subfreezing temperatures? Surviving with no food source?

that's only in our own solar system.... and then there's the unobservable observable universe...

Which is the domain of science fiction writers, not scientists.

[lost_shaman]

Scowl, its estimated that life could thrive in the subsurface of Mars as much as 7 times deeper than life does here on Earth. And what do you mean by saying no food source?

[mcrom901]

All that I have read. Name one.

i don't know what you've read, please be my guest...

Do you have any other models?

that's the whole point, isn't it?

Bacteria in subfreezing temperatures?

methanogens are classed as archaea....

http://www.pnas.org/content/102/51/18292

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1690475/

Which is the domain of science fiction writers, not scientists.

science is not about proving a negative

Edited September 19, 2013 by mcrom901

[Frank Merton]

I think life will turn out to be common, but in forms toxic to us (almost any chemical system other than one based on DNA and amino acids would likely be toxic).

I am doubtful about multi-cellular life and extremely doubtful about technological civilizations. You can't prove a something does not exist by its absence when it could always turn up tomorrow, but you can ask why not by now.

[scowl]

that's the whole point, isn't it?

Yes, the point is that we only have one model of life. The rest is science fiction.

methanogens are classed as archaea....

http://www.pnas.org/...nt/102/51/18292

http://www.ncbi.nlm....les/PMC1690475/

Yeah, the second paper made a big splash years ago but has been rejected. If you add up the "if"s you end up with an extremely low probability of being true yet the author uses the false assumptions to actually calculate how much life in on Mars right now. The author wasn't aware that Greenland and Mars are very different in many other ways and instead assumes they're exactly the same. The author calculates a Martian temperature far warmer than any other estimate, probably because his theory needed to start with 0C otherwise it completely falls apart.

science is not about proving a negative

Science is not about proving false theories correct. Sometimes there are negatives and we just have to deal with them.

[scowl]

Scowl, its estimated that life could thrive in the subsurface of Mars as much as 7 times deeper than life does here on Earth.

Which shows that exobiology is nothing more than unprovable theories.

And what do you mean by saying no food source?

Life needs energy to survive and reproduce. Tell me, what energy exists under the surface of Mars? You have no sunlight and everything suggests that Mars has an ice cold internal core so no heat.

[lost_shaman]

Which shows that exobiology is nothing more than unprovable theories.

Life needs energy to survive and reproduce. Tell me, what energy exists under the surface of Mars? You have no sunlight and everything suggests that Mars has an ice cold internal core so no heat.

No it shows microbes potentially have alot more space to thrive underground on Mars than they do on Earth.

And you really claim to have so much knowledge about geology?

Well if you really did... you would know that there is no way Mars is ice cold to the core as you claimed. Its thought that because of radioactive decay that the Mantel of Mars is around 1,500 deg. F. This is why such a large percentage of the thick Martian crust falls into a tempurature range that could support life.

As for food? What do you suppose these deep underground microbes on Earth are "eating"? You do know there is no sunlight right?

[Frank Merton]

The problem I have with Martian life, unless it is of Terran origin (or we are of Martian origin -- both of which are highly unlikely) is that extremophiles are evolved from non-extremophiles, which implies that you need a more benign environment to get life started.

[bison]

Recent work on Mars seems to strongly indicate that its ancient environment wasn't particularly 'extreme'. The red planet appears to have once had an ocean, flowing water, and a much more substantial atmosphere than it does at present. An ocean and relatively dense atmosphere would tend to moderate day/night extremes of temperature.

[Bavarian Raven]

Recent work on Mars seems to strongly indicate that its ancient environment wasn't particularly 'extreme'. The red planet appears to have once had an ocean, flowing water, and a much more substantial atmosphere than it does at present. An ocean and relatively dense atmosphere would tend to moderate day/night extremes of temperature.

Not even "that" ancient. Recent work has shown that liquids still occasionally flow on the surface, during brief warmer summer spells. The planet is not as hostile as once thought - heck we have lichens and bacteria on earth right now that could survive on mars if they were planted.