Astrobiology, 21st century alchemy?

[Zachary]

I've just been reading this article about somebody else flogging on the Drake equation for the x billionth time, and alot of things in the article really don't seem like science at all to me: http://news.bbc.co.uk/1/hi/sci/tech/7351428.stm

The odds of intelligent life arising on another Earth-like planet are low, a British scientist has calculated.

1st thing:

The reason is that the "habitable lifespan" of an Earth-like planet - estimated at five billion years - will rarely be long enough for complex life to evolve.

oh really?, what piece of magnificent evidence did he glean from his sample size of one to come to that conclusion?

2nd:

the future life span of Earth will be "only" about another billion years - a short time compared to the four billion years since life first appeared on the planet.

25% is a short time now? Any confidence interval describing the length of time it takes for life to form on a habitable planet is going to have error margins way higher than a billion years :/

But it's this that really gets my goat:

Prof Watson identifies four - the emergence of single-celled bacteria; complex cells; specialised cells allowing complex life forms; intelligent life with an established language.

He estimates that the probability of each of these "critical steps" occurring in relation to the lifespan of Earth is no more than 10%.

How did he calculate this probability? How how how? How in the name of [insert nonspecific deity] can anybody give statistical probabilities of events happening when your sample size is one?. It's absurd, it's beyond absurd; it's junk science. Scientists blithely churning out probabilities based on no more than a guess is what gives science a bad name and disillusions the public.

So he's saying the probability of the Cambrian Explosion happening on a habitable planet is less than 10%. I mean, we don't even know how the cambrian explosion happened! A garden gnome sprouted in my yard; I don't know how it happened but I'm going to say the probability of it happening was 10%, because I say so...

"On the other hand, the rapid establishment of life on Earth after its formation may indicate that simple microbial life is relatively common."

Prof Watson completed his PhD under the supervision of James Lovelock, author of the Gaia hypothesis, "whose view of the earth as a whole system has influenced me ever since".

This gets to the crux of it. He is practically making stuff up to get a PhD and parrot his supervisor's rare earth views.

Why do so many astronomers have no integrity with regards to their statistics? I had to write a paper on extraterrestrial life last week and some of the junk I came across was astounding. Why do people use the Drake equation as a basis for some charade of an empirical investigation? It has more free parameters than an alcohol laden night with my housemates. As part of my degree I'm doing a 'life in space' module; to say is a joke would be flattering.

I know we have truly very little evidence on extraterrestrial life but that's no excuse for trying to use statistical methods when you have a sample size of 1. I could see the stupidity of that when I was 16, and yet people are getting PhDs awarded on the basis of this junk science.

[3rdvogon]

I have to say I agree.

Why cannot some people say

"WE DON'T KNOW"

"Wed do not YET have the evidence to make claims either way".

I am all for debating possibilities we can often look at known physical and chemical process and attempt to work out if this or that thing may be feasible. I just get annoyed by people who tell us our galaxy is teaming with intelligent life "because it has to be" or "there is no life out there because life is such a difficult thing to form".

All we can say is there is an absence of evidence within our own galactic neighbourhood. When and only when we can build telescopes capable of imaging a fair range of planets around other stars in our "neck of the woods", allowing us to detect at least the signatures of biological activity, will we then be able to plug a few more numbers into the Drake Equation to turn our statistics from a sample of One to a sample of Fifty.

Even that will not produce a definitive answer but at least it will either increase our absence of evidence or tell us that maybe biology seems to evolve in 3 out 50 star systems. As to whether any of those biological planets has produced "tool using" "city builders" - well that will remain anyone's guess.

[clint]

Why cannot some people say
"WE DON'T KNOW"
"Wed do not YET have the evidence to make claims either way".
...

Sadly, that's how the news media work.
You don't get published saying 'I don't know'.

[JustAFriend]

Just goes to show how stupid journalists can be (hey, I used to be one myself... I know how science-dumb most of 'em are...)

It's glaringly obvious that so far we have been on ONE planet and in 5billion years it has sprouted life, so the odds are 1.0

Kinda like flipping a coin ONCE and getting heads, then announcing that you can NEVER get tails.

[RalofTyr]

Logically correct. So far, the number of solar systems explored ratio to life is 1 to 1. So there's a 100% chance that a system will harbor life.

I kind of agree with that guy's odds, not because of his flawed logic, but my research into a systems, orbits, habitiable zones, time scales etc. etc. And the fact we aren't being bathed in alien TV waves. This human thing called, "Civilization", will probably turn out to be very, very rare in the universe.

Thought, we as humans want to really, really believe we are not alone. Well, we aren't. We have countless worlds of bateria to keep us company until we find the ruins of a long dead alien civilization.

I'm really hoping for more Mars exploration. Because I kind of expect to find higher life form fossils on Mars. Mars has had an Earth-like environment for the first billion years of life. During tha time, Mars would freeze and warm up, freeze and warm up and it is my theory that great climate changes fosters changes that could lead to multi-organisms.

[Ronald Brak]

I'll just mention the Cambrian explosion is not as big a deal as some people make it out to be. It appears many phyla were present before the Cambrian. It may be more an explosion of decent fossils than phyla. If human activity ends up destroying a lot of fossil sites before we go extinct, then in a billion years time sentiant cockroaches will be amazed at the diversity of lifeforms suddenly appearing in the 21st century. (And maybe the sentient cockroaches will conclude that it takes five billion years for intelligent life to emerge.)

[sarongsong]

...It's glaringly obvious that so far we have been on ONE planet and in 5 billion years it has sprouted life...

Could'a been seeded or migrated to, from elsewhere, for all Science knows for sure, tho.

[A.DIM]

Hi Zachary.

Do you also consider Exobiology as 20th century alchemy?

While I agree with much of what you say I have a question which regards this:

This gets to the crux of it. He is practically making stuff up to get a PhD and parrot his supervisor's rare earth views.

I wasn't aware Lovelock's Gaia hypothesis was a rare earth perspective; please explain?

[A.DIM]

Sadly, that's how the news media work.
You don't get published saying 'I don't know'.

Right, and you don't get PhDs saying "all your ideas are flawed, supe"

[GOURDHEAD]

For an approach different from that of the Drake equation, try: http://www.bautforum.com/universe-to...ml#post1224403

[m1omg]

Logically correct. So far, the number of solar systems explored ratio to life is 1 to 1. So there's a 100% chance that a system will harbor life.

I kind of agree with that guy's odds, not because of his flawed logic, but my research into a systems, orbits, habitiable zones, time scales etc. etc. And the fact we aren't being bathed in alien TV waves. This human thing called, "Civilization", will probably turn out to be very, very rare in the universe.

Thought, we as humans want to really, really believe we are not alone. Well, we aren't. We have countless worlds of bateria to keep us company until we find the ruins of a long dead alien civilization.

I'm really hoping for more Mars exploration. Because I kind of expect to find higher life form fossils on Mars. Mars has had an Earth-like environment for the first billion years of life. During tha time, Mars would freeze and warm up, freeze and warm up and it is my theory that great climate changes fosters changes that could lead to multi-organisms.

Oh I am tired with hearing "we dont hearr tv waves blahblahblah."

listen people, we will NEVER hear any waves simply because most of the transmissions stay at planet and even these signals what get out are ruined in noise at pluto and even there you would neeed 2 km antenna to trace any remains of the sign signal

there is a lot of civilisation, but simply the nearest star is 3600 further than pluto, no radiowaves, and from where you have that they would use raqdiowaves or technology at all?anyways i don't belive that "supercivilisation" can exist there are not enough RESOURCES

[Nick Theodorakis]

...
I'm really hoping for more Mars exploration. Because I kind of expect to find higher life form fossils on Mars. Mars has had an Earth-like environment for the first billion years of life. During tha time, Mars would freeze and warm up, freeze and warm up and it is my theory that great climate changes fosters changes that could lead to multi-organisms.

The earth went for about 2 or 3 billion years with nothing more complicated than unicellular organisms living on it. I don't see that one billion years of habitability will inevitably lead to complex organisms.

This is not to say that I disagree that Mars needs to be explored; I'm just pessimistic about finding any evidence of complex fossils.

Nick

[A.DIM]

Oh I am tired with hearing "we dont hearr tv waves blahblahblah."

listen people, we will NEVER hear any waves simply because most of the transmissions stay at planet and even these signals what get out are ruined in noise at pluto and even there you would neeed 2 km antenna to trace any remains of the sign signal

Right, recently on NPR there was a segment wherein an astronomer states that Lucy isn't heard much beyond the solar system.

This, to me, negates the so called "paradox" Fermi proposed.
While the universe should be teeming with ETs they may well not be loud enough to be heard beyond their own systems.
Apparently we aren't.

[sarongsong]

Oh I am tired with hearing "we dont hearr tv waves blahblahblah."...

Hawking, the comedian:

April 21, 2008
Famed astrophysicist Stephen Hawking has been thinking a lot about the cosmic question, "Are we alone?" The answer is probably not, he says...If there is life elsewhere in the universe, Hawking asks why haven't we stumbled onto some alien broadcasts in space, maybe something like "alien quiz shows?"..."Primitive life is very common and intelligent life is fairly rare," he then quickly added: "Some would say it has yet to occur on earth."...
Breitbart

VIDEO: Cambridge University Professor Stephen Hawking on "Why We Should Go Into Space" (4/21/2008) - C-SPAN

[A.DIM]

Hawking, the comedian:

Impeccable comedic timing!

[sarongsong]

Plus, he seemed almost exuberant on stage, smiling the whole while and obviously having a good time.

[RalofTyr]

Oh I am tired with hearing "we dont hearr tv waves blahblahblah."

listen people, we will NEVER hear any waves simply because most of the transmissions stay at planet and even these signals what get out are ruined in noise at pluto and even there you would neeed 2 km antenna to trace any remains of the sign signal

there is a lot of civilisation, but simply the nearest star is 3600 further than pluto, no radiowaves, and from where you have that they would use raqdiowaves or technology at all?anyways i don't belive that "supercivilisation" can exist there are not enough RESOURCES

That's like saying, "I'm tired of their not being any proof, it's just that the proof isn't detectable, so the theory is proven correct".


Eventually, a civilization will colonize the entire galaxy. So, where are they? Why haven't they colonized us?

[eburacum45]

Some tentative conclusions can be drawn from the information we have available.

It seems entirely plausible that life takes a long time to develop into complex multicellular forms; this took several billion years on Earth, and unless it took unusually long on our planet we might expect it to take a comparatively long time on another world.
Perhaps the average development time on other worlds is ten times as fast- perhaps it is ten times slower. If the average development time of complex multicellular life is ten times as fast, then complex biospheres may be common.

The length of time a planet occupies the habitable zone is also important- over time the habitable zone moves outward from the star, as the star heats up. In a billion years or so, our own planet will no longer be in the habitable zone as it is currently understood. Cooler K-class stars get warmer more slowly than our own star, but their habitable zone is much smaller. On the other hand hotter F-class stars have larger habitable zones, but get hotter more quickly, so the zone moves past a planet quite rapidly. I'd suspect that the best class of star for habitability concerns would be a slightly cooler, somewhat longer lived G-class star.

We can't tell much from the absence of radio detection, as numerous discussions on this forum seem to indicate; but some other indications seem to suggest that we are not imbedded in a galactic civilisation. I'd expect to see evidence of past alien exploration (no convincing evidence exists) or current alien presence; I'd also expect to see megastructures in at least some planetary systems, and perhaps emissions or waste heat from interstellar spacecraft or energy generation or collection. For example we can probably exclude the possibility of a civilisation using zero-point energy to generate power, as such a civilisation would probably emit more energy than the stars in the galaxy.

If life is abundant, it does not seem to have developed into a detectable civilisation anywhere near our star- a civilisation using large amounts of energy nearby would have been detected by now. But there might be untold numbers of civilisations with lower levels of energy use throughout our galaxy. One might wonder what prevents a hypothetical civilisation from developing into a detectable one. Are they deliberately hiding from each other?

[A.DIM]

Plus, he seemed almost exuberant on stage, smiling the whole while and obviously having a good time.

I watched his recent TED talk and was sure he fell asleep a couple of times... that was funny.

[A.DIM]

That's like saying, "I'm tired of their not being any proof, it's just that the proof isn't detectable, so the theory is proven correct".

Which theory would be correct?

Eventually, a civilization will colonize the entire galaxy. So, where are they? Why haven't they colonized us?

I don't doubt that eventually a civ will colonize the galaxay.
I don't doubt they already have.
Where are they?
Good question, I guess.
While unproven it seems they're still here buzzing around in our skies.
Why?
Better question.
While unconvincing it seems ancient mythic and religious texts can proffer some insight.


IMHO, of course.

[ravens_cry]

I am attempting to write a science fiction novel where the reason we don't notice anything is because the Soler System has been locked away from the rest of the universe, this is punishment for committing xenocide against the Second Mind, another intelligent life form on the planet. Any attempts to leave the Solar System end in failure.
Of course I think as far being true, I strongly doubt it, though it would explain why we don't here from anybody.

[Neverfly]

I am attempting to write a science fiction novel where the reason we don't notice anything is because the Soler System has been locked away from the rest of the universe, this is punishment for committing xenocide against the Second Mind, another intelligent life form on the planet. Any attempts to leave the Solar System end in failure.
Of course I think as far being true, I strongly doubt it, though it would explain why we don't here from anybody.

It's funny you mention this.
I had read the Giants Trilogy by James P Hogan a few years back.
The last book talks about this, where our solar system was to be encapsulated so that anything that tries to leave it will redirect back inside. It wasn't for punishment so much as for containment- humanity had been deemed too dangerous to be allowed out.
I was thinking about this, idly, during all the expansion and strangeness of observing the universe threads... The thought popped into my head: What if we are already in one of those and that is why everything looks so weird?

(Spoiler Note* The Giants novel goes on to conclude Humanity isn't so bad after-all and no such thing was set into enforcement.)

[agingjb]

I don't doubt that eventually a civ will colonize the galaxay.
I don't doubt they already have.

Hmm. Let's just say that it would would take a lot more evidence, or to be accurate some evidence, for me to be beyond doubt that a civilization has colonised the galaxy (or even that one will).

[Neverfly]

Hmm. Let's just say that it would would take a lot more evidence, or to be accurate some evidence, for me to be beyond doubt that a civilization has colonised the galaxy (or even that one will).

Yes, it's an assumption with little basis.

[A.DIM]

Yes, it's an assumption with little basis.

So you reject the Fermi Paradox as well then?

[3rdvogon]

So you reject the Fermi Paradox as well then?

You cannot apply the Fermi Paradox as proof that there are lots of spacefaring species but they just decide to avoid contact with us. That is applying imagination not reasoning.

All the Fermi Paradox leaves us with is the probability that even if there are any other technological species in our Galaxy, then presumably they are not much more advanced than us. In which case they have either not yet developed viable methods of interstellar travel or have decided that for their own reasons the cost of trying to move out beyond their own star system is more than they are prepared to budget for.

[A.DIM]

You cannot apply the Fermi Paradox as proof that there are lots of spacefaring species but they just decide to avoid contact with us. That is applying imagination not reasoning.

You seem to misunderstand why I asked that question of Neverfly.

Fermi and his cohorts calculated that we should be immersed in a galactic civ and thusly asked "so where is everybody?"

I was asking Neverfly if he might consider Fermi's calculations as "assumptions with little basis."

All the Fermi Paradox leaves us with is the probability that even if there are any other technological species in our Galaxy, then presumably they are not much more advanced than us. In which case they have either not yet developed viable methods of interstellar travel or have decided that for their own reasons the cost of trying to move out beyond their own star system is more than they are prepared to budget for.

I see alot of anthropocentric assumption in here as well, but your starting assumption in this post, that I raised the Fermi paradox as "proof" that they avoid contact, is quite in err.

[agingjb]

Fermi's question, the so-called "paradox", is interesting, and has a lot of possible answers; but I cannot see how it leads to the certainty that there is, has been, or will be, a galaxy wide civilisation.

[A.DIM]

So when I said "I don't doubt they already have" you read "It is certain they already have?"

[SolusLupus]

Eventually, a civilization will colonize the entire galaxy.

This is a premise that is based purely in speculation.

So when I said "I don't doubt they already have" you read "It is certain they already have?"

If you want to get technical, not having any doubt has the same meaning as certainty.