The Goldilocks zone???

Plug

Most of us know what the Goldilocks zone is, its where its not too far from the host star where water will freeze and not too close that it will boil away.
I mean for instance we can be -10c and Spain maybe 1500 miles away could be 15c. In space 1500 miles is absolutely nothing. For a planet to be in the goldilocks zone how precise most that distance be, seems very?

NoQuarter

Good question, I often wonder this myself!

Mahatma coat

Like when they describe something as a Class - M Planet in StarTrek. what are the paramaters and how much wiggle room is there?

The Wiki isnt very helpful.
http://en.wikipedia.org/wiki/Goldilocks_planet

maybe someone has a few simple diagrams that will make the concept easier to grasp.

slade_x

Goldilocks zone, just out of curiosity whats the average age of posters here

Its called the habitable zone for us adults


http://en.wikipedia.org/wiki/Habitable_zone

The easier version:

https://www.e-education.psu.edu/astro801/content/l12_p4.html

www.e-education.psu.edu wrote:

Another visualization of the habitable zone is shown below.
The red region is too warm, the blue region too cool, and the green region is just right for liquid water.
Because it can be described in this way, sometimes it is referred to as the "Goldilocks Zone," too

Suffice to say the habitable zone is quite large for our sun

NoQuarter

Thanks for that slade.

the OP raised a good point though, as you say the habitable zone is quite big, but the temperature difference at one end of the HZ to the other must be massive bearing in mind that the OP pointed out the difference in the distance from spain to norway can be circa 30 degrees and were only talking about a thousand miles or two.

So as humans, is our habitable zone much much smaller?

maninasia

The Goldilocks zone, based on one example, Earth, that's not very scientific isn't it. Liquid water can be sustained by many different means, there are even bacteria on earth that use antifreeze to create their own pockets of liquid water microenvironments from the ice around them (look up the Oort cloud, tell me what it is made of). Radioactivity and gravitational forces can create liquid oceans/lakes. Finally who is to say that our type of life is the most prevalent?

BTW, there could well be life on Saturn's moons and they are not in the Goldilocks zone.

Plug

answers.com wrote:

Because of earth's elliptical orbit around the sun, the distance changes over the course of a year (one complete orbit of the sun):

We are closest at perihelion, during winter in the Northern Hemisphere (around January 3rd) at the minimum distance of 147 million km (91 million miles).

We are farthest away at aphelion, during summer in the Northern Hemisphere (around July 4th) at the maximum distance of 152 million km (94.5 million miles).

So there's about 3.5 million miles of a difference during the year, which is quite big. Maybe the small temperature change in relation to 3+ million miles has something to do with the atmosphere keeping the heat at a more or less constant temperature?

maninasia

Plug wrote: »

So there's about 3.5 million miles of a difference during the year, which is quite big. Maybe the small temperature change in relation to 3+ million miles has something to do with the atmosphere keeping the heat at a more or less constant temperature?

The Earth seems to switch through different stable climatic states, ice ages, snowball earth, Jurassic tropical period etc. This may be influenced by some type of physical 'balancing' process and I suspect it is influenced by bacteria and plantlife too which may be working together (not in a concsious system but as something that evolved from a complex system) to stabilise the environment or minimise temperature fluctuations and therefore perpetuate itself (Gaia hypothesis, e.g. potent greenhouse gases such as methane and CO2 are regulated by the biosphere in a stable state, outside influences such as volcanic eruptions or meteor collisions may throw this equilibrium out of whack and move Earth into an alternative equilibrium, this might sound 'hippyish' but the science is pretty sound, for instance most rocks on Earth have oxygen and therefore their mineral content determined by plant emissions billions and millions of years ago..the influence of the biosphere cannot be ignored!).

Finally the large amount of water on Earth's surface may help to regulate temperature, acting as a heat sink or insulator.

slade_x

NoQuarter wrote: »

but the temperature difference at one end of the HZ to the other must be massive bearing in mind that the OP pointed out the difference in the distance from spain to norway can be circa 30 degrees and were only talking about a thousand miles or two.

Theres a bit of a difference between comparing the two, from one perspective you have the region around the star that would keep the average temperature (keeping in mind the average as the whole of earths surface) above freezing where liquid water can exist and the difference in the angle of the earth in its orbit around the sun. the polar regions are naturally uninhabitable for humans. the tropics and termination regions of the arctic circle are habitable. the tilt of any planet orbiting its star has a significant impact also on what would make a planet habitable

the difference between norway and spain is simple, one is in the tropics that receives the most sunlight per year where as the other is a lot closer with parts in the arctic circle which arguably recieves the least. There is a very delicate balance between both. if the earth were to drift further outward the arctic and antarctic circles would just become larger proportionately to the distance. leaving the habitable zone altogether would render the tropics unhabitable as the they would just disappear, plunging the planet into a constant winter where no part of the planet would be habitable for us without our technology.

maninasia

Yes, but even if ice covered the whole of the earth as long as liquid water existed underneath it or in pockets (which it surely would around geological hot spots and underground where pressure/temperature is higher) then there would still be plenty of life.
So that's why the idea of the goldilocks zone is plainly wrong!
In fact the earth has had a 'constant winter' over large parts of it's history, at one point being snowball earth, http://en.wikipedia.org/wiki/Snowball_Earth, life continued.

bonkey

maninasia wrote: »

life continued.

Exactly. Life continued.

That is distinct from saying that these conditions are suitable for life to begin.

They may be, of course. Its also worth pointing out that the habitable zone doesn't define conditions where life is possible, but rather conditions where the odds appear better for certain forms of life to exist.

slade_x

maninasia wrote: »

Yes, but even if ice covered the whole of the earth as long as liquid water existed underneath it or in pockets (which it surely would around geological hot spots and underground where pressure/temperature is higher) then there would still be plenty of life.
So that's why the idea of the goldilocks zone is plainly wrong!
In fact the earth has had a 'constant winter' over large parts of it's history, at one point being snowball earth, http://en.wikipedia.org/wiki/Snowball_Earth, life continued.

the habitable zone (HZ) is the distance from a star where an Earth-like planet can maintain liquid water on its surface[1] and Earth-like life. The habitable zone is the intersection of two regions that must both be favorable to life; one within a planetary system, and the other within a galaxy. Planets and moons in these regions are the likeliest candidates to be habitable and thus capable of bearing extraterrestrial life similar to our own. The concept generally does not include moons, because there is insufficient evidence and theory to speculate what moons might be habitable on account of their proximity to a planet.

The habitable zone is not to be confused with the planetary habitability. While planetary habitability deals solely with the planetary conditions required to maintain carbon-based life, the habitable zone deals with the stellar conditions required to maintain carbon-based life, and these two factors are not meant to be interchanged.

The habitable zone does not describe a zone where any kind of life could exist anywhere on a planet. we honestly have no idea of other forms of life out there and what condition they require to live. The habitable zone is an aid to find a planet a little like our own in safe zone around its host star, with life thriving on its surface (idealy advanced life that has evolved on its surface)

And the earth has had extremely long periods of winter lke ice ages and mini ice ages yes, but there are not a constant by the very definition of the word constant.

namloc1980

maninasia wrote: »

Yes, but even if ice covered the whole of the earth as long as liquid water existed underneath it or in pockets (which it surely would around geological hot spots and underground where pressure/temperature is higher) then there would still be plenty of life.
So that's why the idea of the goldilocks zone is plainly wrong!
In fact the earth has had a 'constant winter' over large parts of it's history, at one point being snowball earth, http://en.wikipedia.org/wiki/Snowball_Earth, life continued.

Following on from this there is very strong evidence that there is a liquid sub-surface water ocean under the surface of Europa, one of Jupiter's moons. It is believed that the water is kept liquid through tidal stretching of Europa's interior by Jupiter's massive gravitational well. Europa is a long way away from the Goldilocks zone.

maninasia

bonkey wrote: »

Exactly. Life continued.

That is distinct from saying that these conditions are suitable for life to begin.

They may be, of course. Its also worth pointing out that the habitable zone doesn't define conditions where life is possible, but rather conditions where the odds appear better for certain forms of life to exist.

So that should be stated clearly, as a lot of people take it to mean 'life' in general. Plus we only have a dataset of one to base our theories, theories which may well be totally off it we could look at the subsurface of Mars or Europe for example or if we could examine the comets and ice in the oort cloud.
I mean if it was such a 'goldilocks zone' how come Venus and Mars aren't obviously crawling with life, I think the whole idea is way too simplistic.

I think my point about snowball earth and million year long ice ages along with switches between reducing and oxidising atmospheres shows that life can exploit a wide range of conditions.

Johnmb

maninasia wrote: »

So that should be stated clearly,

It is stated clearly if you do the research. Of course, if you are just relying on a paraphrase from an article in a non-technical paper, then you clearly aren't getting the full story.

maninasia

It's a dodgy theory lads...

Johnmb

maninasia wrote: »

It's a dodgy theory lads...

It's actually a pretty sound theory. "If we want to find an Earth-like planet that has Earth-like life on it, where should we look?" - "Look in an area around the star that is very much like the area around the Sun that Earth is in".
Very simple, and very obvious. We only have one example to go on. As already stated, the idea does not, in any way, preclude life from existing or beginning in any other areas, it is specific to Earth-like life on Earth-like planets, and the areas that, based on experience of one, we would be most likely to find them.

maninasia

But Earth life survived snowball earth for millions of years and massive ice ages. A large amount of the biota on Earth is living underground in the rocks (microbial life).There is no strict requirement for habitable zone as stated even for life on Earth. Dodgy theory.

Johnmb

maninasia wrote: »

But Earth life survived snowball earth for millions of years and massive ice ages. A large amount of the biota on Earth is living underground in the rocks (microbial life).There is no strict requirement for habitable zone as stated even for life on Earth. Dodgy theory.

Erm.... Earth never left the habitual zone, even during those periods. Theory still stands, the only example of Earth-like life evolving on an Earth-like planet happened on Earth, and the most likely place to find other Earth-like planets that may have Earth-like life evolving on them is is a similar zone around other stars as Earth is in around the sun. Snowball Earth doesn't mean there was no liquid water btw. And the main thing is stability. Over its history, Earth has been remarkably stable temperature wise, so life could evolve into ever more complex forms. While life can/probably has evolved on less stable planets, and on planets that are much more extreme than Earth, the habitual zone relates specifically to Earth-like life on Earth-like planets. I'm not sure why you don't seem to be able to get your head around that.

maninasia

I know very well the idea of 'golidlocks zone', I think it is ridiculous as nobody knows how to set the inner and outer parameters of such a zone. As I mentioned already the total amount of water on the planet could act as an insulator resulting in Earth's supposed low variation in temperature aswell as influence from biological life in maintaining a certain temperature range ....but as is well known now life exists in a wide temperature variation on Earth. In addition, planets with a frozen surface could easily spawn life or maintain a huge liquid ocean due to various geological processes....it is not neccessarily related to distance from the sun (within very loose parameters). To a subterranean dweller huge temperature variations in the surface atmosphere may have little or no effect! Finally life could be more common on moons than planets, too many things are unknown still.

Here's another question , what about the influence of active tectonics? Mars doesn't have active tectonics now. Maybe tectonics is the answer? TOO many unknowns.

Bohrio

maninasia wrote: »

I know very well the idea of 'golidlocks zone', I think it is ridiculous as nobody knows how to set the inner and outer parameters of such a zone. As I mentioned already the total amount of water on the planet could act as an insulator resulting in Earth's supposed low variation in temperature aswell as influence from biological life in maintaining a certain temperature range ....but as is well known now life exists in a wide temperature variation on Earth. In addition, planets with a frozen surface could easily spawn life or maintain a huge liquid ocean due to various geological processes....it is not neccessarily related to distance from the sun (within very loose parameters). To a subterranean dweller huge temperature variations in the surface atmosphere may have little or no effect! Finally life could be more common on moons than planets, too many things are unknown still.

Here's another question , what about the influence of active tectonics? Mars doesn't have active tectonics now. Maybe tectonics is the answer? TOO many unknowns.

I think that what's happening is that ur not really listening to what people are saying

U seem to think that life can only exist inside the habitable zone

maninasia

I usually don't bother responding to people who don't make an effort to write properly but do yourself a favour and read my posts, especially the last one...you seem mightily confused.

Johnmb

maninasia wrote: »

I usually don't bother responding to people who don't make an effort to write properly but do yourself a favour and read my posts, especially the last one...you seem mightily confused.

He's right though, you seem to be ignoring everything that other posters have told you. You are still making statements giving reasons why the Habitual Zone is wrong because of the variety of temperature within it and the fact that life can exist outside it, despite it being made clear that the habitual zone doesn't say that life will only evolve within that area, nor does the idea say that life will evolve within that area. It's a very simple concept, which you don't seem to understand. Other posters have tried to explain it to you, yet you still persist in repeating the same irrelevant "problems", even though they do not actually provide any problems to the idea of a habitual zone, or the reason such a zone has been proposed.

maninasia

He's can't even write properly and he hasn't even read what I wrote, he's right about nothing.
I've never mentioned anything about a habitual zone, we are talking about the bogus goldilocks zone and how it is not a very useful idea and could very well be very misleading. Look at the moons around Saturn and Jupiter for example, look at what we know and don't know. Mars is in the goldilocks zone near Earth, has fairly similar chemistry and size, the main difference is that on Mars tectonic activity seems to have stopped a very long time ago. Then there is organic material in comets..that obviously could be a suitable living environment for some bacteria. It seems some people don't like they were called up on the shortcomings of a mediocre idea.

maninasia

Johnmb wrote: »

It's actually a pretty sound theory. "If we want to find an Earth-like planet that has Earth-like life on it, where should we look?" - "Look in an area around the star that is very much like the area around the Sun that Earth is in".
Very simple, and very obvious. We only have one example to go on. As already stated, the idea does not, in any way, preclude life from existing or beginning in any other areas, it is specific to Earth-like life on Earth-like planets, and the areas that, based on experience of one, we would be most likely to find them.

Mars is as earth like as they come smack bang in the middle of the goldilocks zone, it's not exactly swarming with life now is it (not that there isn't life in the subsurface), there are other candidates like the moons of Saturn and Jupiter that have just as attractive chance as Earth-life life.

I notice how the argument starts stressing Earth-like life now..but bacteria can exist in a massive range of different environments as we well know..what is 'earth like conditions' per se? Some bacteria prefer CO2 environments, some prefer O2, some break down methane, some take energy from radioactive sources and sulphur, some resist high doses of radioactivity, some can remain dormant for perhaps millions of years, some can survive long periods of vacuum, many live in colonies creating their own minienvironments, some excrete antifreeze to create liquid water microenvironments, bacteria caused the oxygen catastrophe on earth which completely changed 'earth-like' conditions).

http://www.damninteresting.com/how-bacteria-nearly-destroyed-all-life

We can find 'habitual zones' on most rocky planets or comets for many bacteria...we could probably find suitable environments on gas giants or even moons that have methane rain, lakes and oceans..depending on whether those bacteria like any of the above.

Zillah

maninasia wrote: »

He's can't even write properly and he hasn't even read what I wrote, he's right about nothing.
I've never mentioned anything about a habitual zone, we are talking about the bogus goldilocks zone and how it is not a very useful idea and could very well be very misleading. Look at the moons around Saturn and Jupiter for example, look at what we know and don't know. Mars is in the goldilocks zone near Earth, has fairly similar chemistry and size, the main difference is that on Mars tectonic activity seems to have stopped a very long time ago. Then there is organic material in comets..that obviously could be a suitable living environment for some bacteria. It seems some people don't like they were called up on the shortcomings of a mediocre idea.

You're constantly railing against a total strawman that no one is proposing.

The Goldilocks zone simply states that we should try to look for planets with earth-like conditions to find earth-like life.

- Pointing out that there are other conditions under which liquid water and life could appear is irrelevant...no one is saying otherwise.
- Pointing out that Mars has no life despite being on the edge of the habital zone is irrelevant. No one is saying that every planet in the zone must have life.

All that they're saying is that, all things being equal, liquid water (and therefore life as we know it) is very likely to occur on the surface of an earth-like-planet within a band around a star a lot like the zone we currently inhabit. This is not necessarily the only kind of life, this is not necessarily the only place that water can occur, it's just saying that we know it is likely based on our observations of Earth.

Everything that you're railing against are unnecessary assumptions that you're making. You are causing the problem.

maninasia

But liquid water will occur in many many different situations, that's one of my main points http://en.wikipedia.org/wiki/Europa_(moon), Plus moons outnumber planets by a factor of what in our own solar system (there are 168 moons in our solar system alone) and there is probaby more chance of life or even 'earth like life' (whatever that means) on moons than planets (moons can generate extra heat from gravitational forces aswell as tectonic activity...energy source from the sun may not be very important). Bacteria and life will generate energy from whatever available energy source is available.

You go on about Earth like life now knowing how to define it, if you define it as including the majority of life that is bacteria well then the goldilocks zone can stretch through most of the Solar System, read my last post.

In addition Mars HAD liquid water on the surface but doesn't now even though it is in the middle of the goldlilocks zone, obviously the determinants of liquid water are quite complex (not exactly very likely like you state in your post), but there could still be bacteria under it's surface, in fact I'd say it's a near certainty.

Cú Giobach

maninasia wrote: »

But liquid water will occur in many many different situations, that's one of my main points http://en.wikipedia.org/wiki/Europa_(moon), Plus moons outnumber planets by a factor of what in our own solar system (there are 168 moons in our solar system alone) and there is probaby more chance of life or even 'earth like life' (whatever that means) on moons than planets (moons can generate extra heat from gravitational forces aswell as tectonic activity...energy source from the sun may not be very important). Bacteria and life will generate energy from whatever available energy source is available.

The whole discussion around a "goldilocks zone" is about liquid water on the surface of a body.
Its about the search for a body with certain characteristics that are simular to Earth, no other body in this solar system has any of these characteristics.
It is not about searching for life in general.
In fairness you are missing the point here.

maninasia

I guess I have gone off a tangent a bit, I apologise if I offended some people. I just think the idea is very simplistic and the name itself is misleading, they should call it 'possibly liquid water planetary zone' not a 'just right for life zone'.
The point still stands that bacteria don't need large bodies of liquid water.

Johnmb

maninasia wrote: »

He's can't even write properly and he hasn't even read what I wrote, he's right about nothing.
I've never mentioned anything about a habitual zone, we are talking about the bogus goldilocks zone

Okay, right there shows just how much you don't understand. The term "Goldilocks zone" is a nickname for the concept's official name "Habitual zone". If you can't even get the terminology right the chances of you grasping an understanding are incredibly slim.

and how it is not a very useful idea and could very well be very misleading. Look at the moons around Saturn and Jupiter for example, look at what we know and don't know.

Those who would be using it actually understand it, so they would not be mislead. Moons generally are not counted even if they are in the habitual zone.

Mars is in the goldilocks zone near Earth, has fairly similar chemistry and size, the main difference is that on Mars tectonic activity seems to have stopped a very long time ago.

So? It has already been explained to you that the concept does not say, or even imply, that all planets within a habitual zone will have life.

Then there is organic material in comets..that obviously could be a suitable living environment for some bacteria. It seems some people don't like they were called up on the shortcomings of a mediocre idea.

Again, so? Earth like life on Earth like planets is what the concept deals with. Since when is a comet an Earth like planet? It would seem that your misunderstanding of basic terminology goes beyond the name of the concept you are trying to discuss.

Mars is as earth like as they come smack bang in the middle of the goldilocks zone, it's not exactly swarming with life now is it (not that there isn't life in the subsurface), there are other candidates like the moons of Saturn and Jupiter that have just as attractive chance as Earth-life life.

Already repeating yourself, despite it having nothing to do with the concept you are discussing. As for Mars, not every planet in a habitual zone will have life, the concept never suggests otherwise. As for Saturn's and Jupiter's moons, what part of "Earth like" are you not getting?

I notice how the argument starts stressing Earth-like life now..

It doesn't just start doing that now, it has always done it, from the start. That's what the concept was created for. Earth like life on an Earth like planet.

but bacteria can exist in a massive range of different environments as we well know..

Good for bacteria, the concept also never said life couldn't exist elsewhere. It doesn't make any comments on other forms of life, nor does it make comments on planets in other areas of a planetary system.

what is 'earth like conditions' per se?

Look out your window, there's an example. An Earth like planet, much like Earth, will not have uniform conditions.

Some bacteria prefer CO2 environments, some prefer O2, some break down methane, some take energy from radioactive sources and sulphur, some resist high doses of radioactivity, some can remain dormant for perhaps millions of years, some can survive long periods of vacuum, many live in colonies creating their own minienvironments, some excrete antifreeze to create liquid water microenvironments, bacteria caused the oxygen catastrophe on earth which completely changed 'earth-like' conditions).

http://www.damninteresting.com/how-b...royed-all-life

That's nice for them, but again, has nothing to do with the concept being discussed.

We can find 'habitual zones' on most rocky planets or comets for many bacteria

Actually, no you can't. See, this comes down to not understanding the terminology. Planetary habitability is a different concept. The habitual (Goldilocks) zone refers to a planets place within its planetary system, and that systems place within its galaxy (although the latter has been much less defined due to a lack of research).

...we could probably find suitable environments on gas giants or even moons that have methane rain, lakes and oceans..depending on whether those bacteria like any of the above.

We probably could, but since they are not Earth like, the concept doesn't even try to cover them.

But liquid water will occur in many many different situations, that's one of my main points http://en.wikipedia.org/wiki/Europa_(moon), Plus moons outnumber planets by a factor of what in our own solar system (there are 168 moons in our solar system alone) and there is probaby more chance of life or even 'earth like life' (whatever that means) on moons than planets (moons can generate extra heat from gravitational forces aswell as tectonic activity...energy source from the sun may not be very important). Bacteria and life will generate energy from whatever available energy source is available.

Once again, you are repeating an irrelevant point despite it already being explained to you that it is irrelevant. The Habitual zone concept never claimed that the habitual zone was the only place to find water and/or life. Nor has it ever claimed that you will find water and/or life.

You go on about Earth like life now knowing how to define it, if you define it as including the majority of life that is bacteria well then the goldilocks zone can stretch through most of the Solar System, read my last post.

Which would make it a daft concept, as it wouldn't narrow down any search areas. Also, while you may not have noticed, life on Earth, and therefore Earth like life, contains more that just bacteria.

In addition Mars HAD liquid water on the surface but doesn't now even though it is in the middle of the goldlilocks zone,

Well its not really in the middle, but regardless, you are repeating not only the same erroneous assumption, but you are using the same example, again! The concept does not say, and never has said, that all planets within the zone would have water and/or life.

obviously the determinants of liquid water are quite complex (not exactly very likely like you state in your post), but there could still be bacteria under it's surface, in fact I'd say it's a near certainty.

Good for you, (and the bacteria), but irrelevant to the Habitual Zone concept. Although, if life does/did exist on Mars and that gets proven, then the Habitual Zone concept would gain more weight as we'd then be 2 for 2 with our known samples!

I guess I have gone off a tangent a bit, I apologise if I offended some people. I just think the idea is very simplistic and the name itself is misleading, they should call it 'possibly liquid water planetary zone' not a 'just right for life zone'.

Those who are involved in the search and research understand the terminology quite well and don't get confused by it. So it is not misleading to the people who would actually be using the concept.

The point still stands that bacteria don't need large bodies of liquid water.

Once again, good for the bacteria, utterly irrelevant for the concept.

maninasia

Yah try to be nice to people and feed them a bone and this is what happens.

Goldilocks Zone = Habitable Zone!
http://en.wikipedia.org/wiki/Habitable_zone

Seems like somebody is telling porkie pies about 'habitual zone'.

But even from this definition it is just such a ridiculous concept...habitable zone my arse!

Still not sure on the whole Earth-like life and Earth-like conditions bit...as I have explained VERY clearly Earth-like life is happy to live in the massive array of conditions found on Earth (these conditions themselves have changed enormously over billions of years and different time periods), these conditions can be replicated on different parts of moons or planets or even on comets in different zones.

maninasia

Seems like I'm not the only one who thinks like this, from the wiki article above.


Criticism

• The concept of a habitable zone is criticized by Ian Stewart and Jack Cohen in their book Evolving the Alien, for two reasons: the first is that the hypothesis assumes alien life has the same requirements as terrestrial life; the second is that, even assuming this, other circumstances may result in suitable planets outside the "habitable zone". For instance, Jupiter's moon Europa is thought to have a subsurface ocean with an environment similar to the deep oceans of Earth. The existence of extremophiles (such as the tardigrades) on Earth makes life on Europa seem more plausible, despite the fact that Europa is not in the presumed CHZ. Astronomer Carl Sagan believed that life was also possible on the gas giants, such as Jupiter itself. A discovery of any form of life in such an environment would expose these hypothetical restrictions as too conservative. Life can evolve to tolerate extreme conditions when the relevant selection pressures dictate, and thus it is not necessary for them to be "just right".[28]

• Differing levels of volcanic activity, lunar effects, planetary mass, and even radioactive decay may affect the radiation and heat levels acting on a planet to modify conditions supporting life. And while it is likely that Earth life could adapt to an environment like Europa's, it is far less likely for life to develop there in the first place, or to move there and adapt without advanced technology. Therefore, a planet that has moved away from a habitable zone is more likely to have life than one that has moved into it.[29]

maninasia

I have since discovered this fact that I was not aware of previously.

Look at this picture- http://en.wikipedia.org/wiki/File:Titan_cutaway.svg

I think too much emphasis is put on bodies of liquid water at the surface. The emphasis should be on bodies of liquid water, period. After all the ocean is supposed to be where life got started or at least was first predominant. How much of the life lives on the surface of the ocean. Bacteria can exist happily from the surface right down to the sea floor and then far below the sea floor.


Read the wiki here.
http://en.wikipedia.org/wiki/Titan_(moon)

Cú Giobach

maninasia wrote: »

I think too much emphasis is put on bodies of liquid water at the surface. The emphasis should be on bodies of liquid water, period. After all the ocean is supposed to be where life got started or at least was first predominant. How much of the life lives on the surface of the ocean. Bacteria can exist happily from the surface right down to the sea floor and then far below the sea floor.

Just a quick question,
What does the fact that life is probably abundant in water under the surface of icy moons/planets or under the surface of rocky ones and maybe floating in the atmospheres of gassy ones or even free floating in space got to do with the search for a spot that could be called Earth like (think the savannas of Africa or the Rainforests or even your own back garden)??
"Earth like" just means a huge variety of life living on the surface of a planet, all the quotes you gave were dubunking an argument nobody is giving, you practically acknowledged this in an earlier post, then go off on one again.
Looking for a place similar to your own home is quite a natural thing to do and it's quite understandable that this is something we are looking for.
There would only be a problem if that was the only thing we were searching for but since it isn't (by a long shot), what on earth is the problem??

maninasia

My problem is the terminology first of all. Goldilocks zone is interchangeable for habitable zone (habitable zone supposedly being the grown-up scientific term for this), habitable zone means the zone that life could inhabit and then that means they mean areas that need liquid water on a planet but not only that it means the distance from the sun within a rather narrow range, when much of Earth life (i.e. bacteria/archaea) could survive off Earth outside the supposed habitable zone..basically the idea behind it is incorrect if you understand anything about microbes or evolution or the history of the Earth.

Second of all the Earth has a wide range of habitats and life on earth survives in liquid water even when frozen on top, it also survives on land and the subsurface, life even survives and prospers in frozen ice (algae/microbes/some crustaceans). What part of earth do we choose to be earth-like (answer you say large bodies of liquid water on surface but then you might miss Mars even though it could have life under the surface).

Third conditions on earth have changed tremendously over the years, what 'earth-like' period are we talking about? Now, snowball earth, earth before the oxygen catastrophe, the jurassic, before plants evolved, when?


I was okay about leaving this alone but when I found Goldilocks zone is interchangeable for habitable zone (and habitable zone is the supposed scientific term for it) that set me off again

Cu Giobach..are you forgetting something? Huge amounts of earth-life (as per your definition with all the national geographic favourites we know and love, not my definition by the way) live UNDER THE SURFACE of the ocean. We have just as much chance of finding earth-like life (at least as per your marine NGC special) on a moon than on a planet. My point being that if liquid water is the concern the goldilocks zone strict definition as in the distance from the sun is ignorant. Now as there are people familiar with astronomy here that is a massive gaping hole in this theory as there are more moons with liquid water than planets in our solar system and those moons aren't even in the 'goldilocks zone' meanwhile Mars is the Goldilocks zone and it is frozen solid.

Cú Giobach

maninasia wrote: »

Cu Giobach..are you forgetting something? Huge amounts of earth-life (as per your definition with all the national geographic favourites we know and love, not my definition by the way) live UNDER THE SURFACE of the ocean. We have just as much chance of finding earth-like life (at least as per your marine NGC special) on a moon than on a planet. My point being that if liquid water is the concern the goldilocks zone strict definition as in the distance from the sun is ignorant.

I am not forgetting anything :rolleyes: and I defined nothing, I asked you a question, What is wrong with searching for planets where liquid water can be stable on the surface of a planet??
The search for planets with this characteristic is not THE search for life, but the search for a certain(ish) kind of "ecosystem" .
Of course the zone where this is possible depends on many variables from the size/mass of the star and planets, the thickness of an atmosphere etc....consequently it is a very lose term, but it is a handy guide. ie close as Mercury....too hot, far as Jupiter....too cold.
The problem here is you seem to be assuming (that is the impression you are giving) everyone who comments on this zone hasn't a clue about what is out there, and this is quite simply wrong.
You are going on about the likes of Europa etc and this has nothing to do with the topic under discussion.
Go outside, stand on a hill in the countryside and look around, that is the kind of environment that is being talked about, where would you yourself look for this kind of environment? Not on an icy moon I hope.

Now as there are people familiar with astronomy here that is a massive gaping hole in this theory as there are more moons with liquid water than planets in our solar system and those moons aren't even in the 'goldilocks zone' meanwhile Mars is the Goldilocks zone and it is frozen solid.

Since the term "goldilocks zone" is referring to liquid water on the SURFACE of a body, I will ask you, what the hell does the fact that there is a huge amount of subsurface water on bodies around the solar system got to do with anything??
You are just going on about where life in general could be found and totally ignoring the point again and again.

The terms Habitable and Goldilocks zones in this context are not strict scientific terms and are only roughly referring to a certain kind of area.

Johnmb

maninasia wrote: »

My problem is the terminology first of all.

I think this sums up your position nicely. You don't understand the terminology, and it is either going over your head or you are just too stubborn to pay attention when others have tried to explain it to you, and show you where your errors are. But ultimately, it is your problem. Everyone who would be using the concept, or following those that do, understands the terminology just fine. And it makes perfect sense for what it is. Are there other areas to look in for life? Yes, obviously. Based on the samples we actually have now (i.e. Earth), the Habitual zone concept makes sense, if you have to narrow down your search area, then narrow it down to something as similar as possible to the only place we currently know of that definitely has life that we are capable of recognising as life. Simple really.

Johnmb

maninasia wrote: »

Yah try to be nice to people and feed them a bone and this is what happens.

Goldilocks Zone = Habitable Zone!
http://en.wikipedia.org/wiki/Habitable_zone

Seems like somebody is telling porkie pies about 'habitual zone'.

What specifically do you think is a "porkie pie"?

But even from this definition it is just such a ridiculous concept...habitable zone my arse!

Still not sure on the whole Earth-like life and Earth-like conditions bit...as I have explained VERY clearly Earth-like life is happy to live in the massive array of conditions found on Earth (these conditions themselves have changed enormously over billions of years and different time periods), these conditions can be replicated on different parts of moons or planets or even on comets in different zones.

And whoever said they couldn't be? You still choose to ignore what the Habitual zone concept actually is, and why it exists.

maninasia

It's habitable zone, not habitual zone. Habitable zone as a terminology is wrong because as I have clearly explained already earth-like life (i.e. bacteria/marine life at the very least) can easily live outside the defined area as expressed in distance from the sun and the need for a liquid surface (tell me... WHY the need for a liquid surface, even Earth didn't have a liquid surface for millions of years) and the need for it to be a planet. With the number of moons outnumbering planets by a factor of 10-20X in any given solar system it could easily make as much or even more sense to look at the moons for earth-like life.

maninasia

'The terms Habitable and Goldilocks zones in this context are not strict scientific terms and are only roughly referring to a certain kind of area. '

So you admit they are not very scientific now . As I said the whole idea is ridiculous as the parameters are so loose as to make the idea meaningless and even misleading.

Cú Giobach

maninasia wrote: »

So you admit they are not very scientific now . As I said the whole idea is ridiculous as the parameters are so loose as to make the idea meaningless and even misleading.

What do you mean by "admit Now" I never claimed anything else,
Why can't you actually respond to anything I have written, you haven't actually commented on a single point I have made.

maninasia wrote: »

it could easily make as much or even more sense to look at the moons for earth-like life.

So you think we will find a rainforest on Enceladus. Because what is being looked for is a possible biosphere as varied as the one here.

FFS what is it about the concept of the search for an "Earth like" planet do you not understand, it really is a simple concept that even an 8 year old would understand.

There are people out there looking for traces of past and present life on Mars, people working on ways to explore Europa, Enceladus etc, there are people working to find traces of life all over the solar system and there are people looking for a possible "Earth like" extrasolar planet.
The area where one of these planets/moons could be found would be in place where liquid water would be stable on the surface and could be HABITABLE for humans (without a pressure suit and/or oxygen breathing app).
How many times do you have to be told the term doesn't refer to the ONLY place life can be found.

Since this search is not the only one going on as I said earlier by a long shot, I will ask you again and would appreciate an answer this time (you haven't answered a single question I have put to you yet), What is wrong with this search??

From your comments on every single thread here regarding ETlife I can quite comfortably state, thank f*ck you aren't in a position of power (funding etc) in NASA, SETI etc as your obsession with your own theories and inability to see past your own ideas (The history of science is full of such people) would curtail and narrow down what is a very broad and wide ranging search , and many of the greatest discoveries in science have been from quite unexpected directions.

Johnmb

maninasia wrote: »

It's habitable zone, not habitual zone. Habitable zone as a terminology is wrong because as I have clearly explained already earth-like life (i.e. bacteria/marine life at the very least) can easily live outside the defined area as expressed in distance from the sun and the need for a liquid surface

And you have had it clearly explained already that the Habitable zone concept does not, and never has, say otherwise. What is it that is so difficult for you to understand about such a simple thing?

(tell me... WHY the need for a liquid surface, even Earth didn't have a liquid surface for millions of years) and the need for it to be a planet.

Because that was how they chose to narrow down the search. While Earth may not have always have had a liquid surface, life is not believed to have started here until liquid water established itself on the surface.

With the number of moons outnumbering planets by a factor of 10-20X in any given solar system it could easily make as much or even more sense to look at the moons for earth-like life.

That's for other people who are using other concepts to narrow down their searches. Those who are using the Habitable zone criteria are not interested in the moons (not least because it is impossible to find any outside our solar system at this point in time). Seriously, do you think that there is only one group of people looking for evidence of non-Earth based life, and that they are only using the Habitable zone concept for their search?

maninasia

'From your comments on every single thread here regarding ETlife I can quite comfortably state, thank f*ck you aren't in a position of power (funding etc) in NASA, SETI etc as your obsession with your own theories and inability to see past your own ideas (The history of science is full of such people) would curtail and narrow down what is a very broad and wide ranging search , and many of the greatest discoveries in science have been from quite unexpected directions.'

This is quite amazing when it is I stating that people need to be more open-minded than focusing on such a thing as a Goldilocks zone. It is also I who has explained clearly how most Earth-like life i.e. bacteria, exists in a vast variety of environments and that 'earth-like' is actually quite hard to define when you really think about it. I understand the idea of looking for planets similar to Earth as part of a strategy for the search for ET life but as I explained the terminology of Goldilocks zone and Habitable zone is misleading and rankles with me.

The likeliehood of even an 'earth-like' planet supporting human life is extremely low. The atmospheric ratio of gases would be different, the strength of gravity would be different, the magnetosphere would be different, the length of night/day/seasons would be different, the biota different, the types of salt and salt concentration in the water would be different. It is going to be one in a million planets that support life as diverse as earth that we could just land on and be 'habitable' for humans or even most other animal or plant species on Earth.

The focus on liquid water surface doesn't make too much sense either. Looking for a body of liquid water, I get that, but liquid water surface, seems not too neccessary.

SETI is doing a poor job of looking for life, they only recently copped on that most intelligent life would probably be machine based, 40 years after science fiction greats like Isaac Asimov gave them the game plan. NASA is not doing a great job either otherwise they would have sent some nucleic acid/organic material detectors with their latest instruments to Mars insted of waiting for another 10-20 years, it wouldn't be too hard to do better than those organisations have been doing (read about the ambiguity from original viking lander..it is actually possible that life has been detected already...there was no conclusive result http://news.discovery.com/space/viking-lander-mars-microbes.html). Why has it taken so long to repeat and improve upon these experiments?
They are getting there but very very slowly.

Johnmb

maninasia wrote: »

This is quite amazing when it is I stating that people need to be more open-minded than focusing on such a thing as a Goldilocks zone. It is also I who has explained clearly how most Earth-like life i.e. bacteria, exists in a vast variety of environments and that 'earth-like' is actually quite hard to define when you really think about it. I understand the idea of looking for planets similar to Earth as part of a strategy for the search for ET life but as I explained the terminology of Goldilocks zone and Habitable zone is misleading and rankles with me.

I honestly can't believe that anyone who knows how to turn on a computer can really be this slow. That just leaves me to assume you are trolling.

Cú Giobach

maninasia wrote: »

This is quite amazing when it is I stating that people need to be more open-minded than focusing on such a thing as a Goldilocks zone. It is also I who has explained clearly how most Earth-like life i.e. bacteria, exists in a vast variety of environments and that 'earth-like' is actually quite hard to define when you really think about it. I understand the idea of looking for planets similar to Earth as part of a strategy for the search for ET life but as I explained the terminology of Goldilocks zone and Habitable zone is misleading and rankles with me.

The focus on liquid water surface doesn't make too much sense either. Looking for a body of liquid water, I get that, but liquid water surface, seems not too neccessary.

In the first quote you say how open minded you are and in the second you show how you are not.
You also say people should be more open minded than looking for a "goldilocks zone", all your arguments would be valid if the search was only or primarily for life in such an area and since this is actually quite a small part of the search, all you are advocating is dropping something you don't think is important.
Liquid water stable in the long term, on the surface of a body would be an amazing discovery. Of course it is not necessary or essential for life and your comment of "not necessary" shows you haven't taken the slightest bit of notice of anything that has been said in this rather sad discussion.

The likeliehood of even an 'earth-like' planet supporting human life is extremely low. The atmospheric ratio of gases would be different, the strength of gravity would be different, the magnetosphere would be different, the length of night/day/seasons would be different, the biota different, the types of salt and salt concentration in the water would be different. It is going to be one in a million planets that support life as diverse as earth that we could just land on and be 'habitable' for humans or even most other animal or plant species on Earth.

Thanks for the quite unnecessary lesson.
Well, one in a million leaves how many (I'll let you do the maths).
Since the likelyhood of traveling to the stars is pretty remote at the moment, I wouldn't be too worried about any of the above.

Quite simply you are trying to argue that the search for water on the surface of a body isn't necessary because life can exist elsewhere and I am arguing that the search, although not necessary or essential in the search for life, is important scientifically. Also, from an anthropocentric viewpoint, a water based biosphere like what we have here would be quite a discovery.

maninasia

You are the one talking about a planet that could support human life, but I am not as humans are only one tiny part of life on earth, so as you can the definition of earth-like is very very broad. There is value in searching for a planet with liquid water, but there is no need to exclude areas where liquid water bodies would be frozen at the surface, it seems far too arbitrary.

maninasia

Johnmb wrote: »

I honestly can't believe that anyone who knows how to turn on a computer can really be this slow. That just leaves me to assume you are trolling.

I guess you are a 'habitual' misreader of posts too. You should really check your terminology before giving lectures to others!

Cú Giobach

maninasia wrote: »

You are the one talking about a planet that could support human life, but I am not as humans are only one tiny part of life on earth, so as you can the definition of earth-like is very very broad. There is value in searching for a planet with liquid water, but there is no need to exclude areas where liquid water bodies would be frozen at the surface, it seems far too arbitrary.

Who here either mentioned or even hinted at excluding icy bodies from a search?? The only person mentioning excluding anything is you.
This comment shows without any doubt that you have not understood one word that has been said to you over the past 3/4 days.

Earth like, is usually referring to a broad biosphere containing life underground/water on the surface and in the atmosphere, simples.
You seem to be under the delusion that anyone who mentions searching for a body with water on the surface is discounting subsurface water, where you got this idea is anybodys guess but you really should get rid of it.
You are defiantly taking the piss now, so i am going to finish this discussion.

maninasia

Plenty of people stated that because snowball earth wasn't permanent that is why life prospered on Earth but at least continued. Well yeah on land..but in the ocean and the subsurface? Plenty of microbes LIVE in ice and rocks. One thing I agree on this thread has run it's course.

Cú Giobach

maninasia wrote: »

Plenty of people stated that because snowball earth wasn't permanent that is why life prospered on Earth but at least continued. Well yeah on land..but in the ocean and the subsurface? Plenty of microbes LIVE in ice and rocks. One thing I agree on this thread has run it's course.

So what?? What has that got to do with the discussion??

maninasia

Welcome back, that was quick. Microbes are earth life too, we are all descendants of microbes, in fact we are just complex microbes in reality and there are more microbe cells in our body than our own body cells. For billions of years only single celled microbes existed on earth. Earth-like life i.e. microbes, don't need large bodies of liquid water.