Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: 1 2 [3] 4 5   Go Down

Author Topic: Kepler mission adds more weight to our solar system not being the norm.  (Read 24066 times)

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #50 on: September 22, 2010, 10:59:51 pm »

I find all these discussions/arguments fascinating, thank you.

I also agree that we seem determined to find some life form very much like us. Why?

I try to imagine that there may be some form of life but what it will be like eludes my thought processes. Why should it be carbon or hydrogen based? But I guess it then raises the question of what do you mean by "life form"?

You also raise the issue of our and their "intentions". I guess that depends, in the first instance, on our ability to communicate.

Another fascinating thought I often have is, would they have a God or Gods? If you are a Christian surely you must ask do they know Lord and is He their Saviour also?

Encountering the unknown triggers a natural human response of fear/suspicion which is quickly followed by aggression on our part. It is a natural and understandable safety mechanism, probably most difficult to control. For example not only do we not speak to our neighbours, before we get to know them we ostracise them if they are foreign or coloured !

Any Earth world leader who walked up to an alien and said "Welcome" would probably be killed.....not by the alien but by his or her electorate !

Roger in France.


Im not sure that people who consider the possibility of alien life are determined to find it like ourselves. I think we are on the cusp of discovering alien life on Mars or some of the moons of Jupiter etc. Obviously I dont have a scientific paper or thesis to satisfy a certain poster on here though! I think is only the general population, fed on a diet of hollywood films etc, who see alien life as being more or less humanoid and 'being like us.'

I think the reason why its a popular view life would be carbon based rather than any other element is because carbon molecules combine with others very well. That's not to say that alien life definitely wont be based on any other element though. (Again, I dont have any scientific papers to satisfy a certain poster.)

I've said in another thread I think we are probably the oldest most technologically advance race in our galaxy right now (again, no science paper Im afraid!) so think the chances of there being other intelligent life out there to communicate with us as being remote.

Having said that, its a statistical probability that if there are many advanced alien races, there will be as many benevolent as malevolent ones.
Logged

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #51 on: September 23, 2010, 10:26:44 am »


...I think we are on the cusp of discovering alien life on Mars or some of the moons of Jupiter etc....

I think the reason why its a popular view life would be carbon based rather than any other element is because carbon molecules combine with others very well. That's not to say that alien life definitely wont be based on any other element though. (Again, I don't have any scientific papers to satisfy a certain poster.)




You hardly need any references for these assertions, which are completely in line with current thinking. If you want any, there are many available - nowadays exobiology conferences are quite common. Here are a few you might be interested in...

http://astrobiology.nasa.gov/exobiology/?pg=2
http://www.spacedaily.com/news/life-00p1.html
http://books.nap.edu/openbook.php?record_id=11919
http://www.pnas.org/content/98/3/805.full.pdf
http://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry
...



I've said in another thread I think we are probably the oldest most technologically advance race in our galaxy right now (again, no science paper Im afraid!) so think the chances of there being other intelligent life out there to communicate with us as being remote.



Current understanding of the development of organic life suggests that it might be common wherever the conditions allow it to exist. Our own planet, developed life just about as soon as it cooled down - sufficiently rapidly for there to be a sizeable body of belief that life was 'seeded' from space rather than developed terrestrially.

There are two oddities in the history of 'Life on Earth' - the rapidity of its initial development, and the peculiar delay in the development of 'higher' intelligence. Most of the more complex life forms which have inhabited this planet seem to have had a fair degree of intelligence - it is needed for both predator and herd lifestyles. What is surprising is that the kind of abstract higher intelligence developed recently by a few species of mammals (notably cetaceans and primates) seems to have taken a very long time to occur. You would think, if it had survival value, that the fish or amphibians would have developed it a lot earlier. They have been going for 500m years and 360m years respectively - mammals have only been going for 200m, dolphins and apes are about 40m years old and we have only been going for perhaps 2m years. Why is this?

This suggest to me that, if you want to consider the prevalence of higher intelligence in the universe, paeleobiology is a more important subject than astronomy. Of course, there are some speculations that the giant reptiles of 300m years ago DID develop intelligence, but it turned out not to have survival value, and so died out quite fast...
Logged

dreadnought72

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,898
  • Wood butcher with ten thumbs
  • Location: Airdrie, Scotland
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #52 on: September 23, 2010, 02:25:27 pm »

Big brains cost a lot.

Ours weigh about 2% of the total body mass (considerably less for people in government!) but use a fifth of the body's energy. From an evolutionary point-of-view that's an incredibly expensive investment, and not least when you add in the risks - giving birth to a human is dangerously hard work, and you end up with an infant incapable of much for a year or so.

You can get by on tiny brains - an ant has around 10,000 neurons, a bee about 800,000. Plenty for the things they do, for predation, for social grouping, etc.

Developing the millions of neurons used by mammals, and the tens-of-billions used by us strikes me as an aberration more than the norm. Think of it as an mammalian arms-race that has spun out of control, if you like. We've left the almost-steady-state of unicellular life, and the slow progression of big-enough-brained multicellular life, and only very recently accelerated to a position where (with our mighty brains) we can wipe out everything. Or - perhaps in a century or two - upload human existances into non-biological lifeforms.

Andy
Logged
Enjoying every minute sailing W9465 Mertensia

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #53 on: September 23, 2010, 08:47:41 pm »


Big brains cost a lot.

Ours weigh about 2% of the total body mass (considerably less for people in government!)


Presumably that's because sedentary jobs make you fatter, rather than make your brain smaller... :} :}


You can get by on tiny brains - an ant has around 10,000 neurons, a bee about 800,000. Plenty for the things they do, for predation, for social grouping, etc.

.


Yes - a roundworm can get by on 302!  But I think there is a bit more difference between the insects and higher orders. A single ant does not really predate, and I carefully used the words 'herd lifestyles' in an effort to distinguish between the social insects and animals like cows. Anthills aren't herds, and most insects seem to have very simple pre-wired responses...

I think your figure for humans is a total neuron count? I have seen neuron counts for humans of approx 11bn in the cerebral cortex. For comparison, chimps weigh in at about 6.2bn, dolphins at 5.8bn, cats at about 0.3bn and dogs at 0.15bn, which certainly makes humans superior, but not fantastically so. You are correct, of course, that we have specialised in brain power to the detriment of other bodily aspects, and this may prove to be counter-productive in the long (or medium!) term.

But it still leaves the question of why this neural arms-race did not occur in fish or reptiles, and why the world had to wait for 500m years of complex animal evolution before one group developed 'high intelligence' in less than 10m years...


Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,773
  • Location: Blackpool, Lancs, UK
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #54 on: September 24, 2010, 10:22:13 am »

Evolution only happens where it is needed. 
If you live in a benign climate, with potable water laid on on a regular basis, abundant food there for the taking and somewhere comfy to rest at night, what incentive for change is there?  Change becomes needed when conditions are marginal, and some new aspect of lifestyle that gives an advantage, whether its the use of a stick to get an advantageous supply of termites or the use of a shady leaf to see the fishes better will see some individuals have a better chance of survival.  Those who exhibit traits for better survival will have more descendants than those who don't, and these traits will tend to be passed on.  Not only the trick itself, but the ability to envision further new tricks. 
As humans, we tend to be better at gathering new tricks than most other creatures that we share the planet with.  Whether the tricks that we have learned are ultimately advantageous or a blind alley remains to be seen.
Having lots of neurons only really counts if they get used, but in the case of the apes from a few million years ago, it might have been a change in conditions that forced a change of diet that in turn caused some individuals to start growing bigger brains.  And it could have been a freak mutation triggered by a stray cosmic ray that laid the seed for the exponential rate of change.  Remember that exponential rates start long and slow, we think we are on the steep bit at the moment, but we could be fooling ourselves.  Being able to think does that for you, as well.
Just a random thought - when did opposable thumbs get invented?
Logged
"With the right tool, you can break anything" - Garfield

dreadnought72

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,898
  • Wood butcher with ten thumbs
  • Location: Airdrie, Scotland
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #55 on: September 24, 2010, 11:09:58 am »

But it still leaves the question of why this neural arms-race did not occur in fish or reptiles, and why the world had to wait for 500m years of complex animal evolution before one group developed 'high intelligence' in less than 10m years...

Fish, reptiles and birds: I suspect the filter there is possibly egg size.

The biggest dinosaur eggs are not much bigger than ostrich eggs. Much bigger and they'd be unbreakable to the "inmate" - and for air-exchange to the developing embryo, that old surface-area/volume ratio works against you as the size increases. A limit on egg size may well force a limit on brain size - and therefore you'd require mammalian/live-born young to expand evolution in the "big-brained" direction.

To answer Malcolm's question - opposable thumbs are great for hanging onto things. No surprise our tree-climbing ancestors had them around fifty million years ago! I have read reports which suggest our ancestor's ability to squat helped free up the role of our fore limbs into more manipulative and dextrous directions, and that this helped promote brain expansion. Though - and no doubt David Attenborough would agree - any element of the body that falls well outside the "norm" (tails of birds-of-paradise, songs of songbirds, brains of humans) has been driven by sexual selection.  %)

Andy
Logged
Enjoying every minute sailing W9465 Mertensia

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #56 on: September 24, 2010, 11:36:35 am »


Fish, reptiles and birds: I suspect the filter there is possibly egg size.



Umm....no, not birds. I was talking about life forms before the mammals, and birds are distinctly after mammals. Though you might also think of them as reptile variants...

But you make a good point about birth size -  animals with intelligence do all seem to have large young.  Which turns the question of 'Where might we find intelligence?' into ''Where might we find big babies?'...
Logged

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #57 on: September 30, 2010, 09:05:29 am »


First habitable exo Earth to be found http://www.newscientist.com/article/dn19474-is-there-a-moores-law-for-science.html sometime in May 2011 if this is to be believed.

Can the rate of past discoveries be used to predict future ones? We may soon find out. Two researchers have used the pace of past exoplanet finds to predict that the first habitable Earth-like planet could turn up in May 2011.


Actually, the first 'habitable exo Earth' to be found according to this definition has just been announced (yesterday). It is Gliese 581g, around 20 ly away. http://arxiv.org/abs/1009.5733 refers.

From the Abstract: "..If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets..."

It is beginning to look as if systems with Earth-like planets are quite normal ....
Logged

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #58 on: September 30, 2010, 08:51:11 pm »


Actually, the first 'habitable exo Earth' to be found according to this definition has just been announced (yesterday). It is Gliese 581g, around 20 ly away. http://arxiv.org/abs/1009.5733 refers.

From the Abstract: "..If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets..."

It is beginning to look as if systems with Earth-like planets are quite normal ....


You think? Hardly but you've given me the best laugh I've had all week with this post.

Its a tidally locked planet orbiting a red dwarf 'star.' With one side tidally locked the planet tidally locked, one side will get all the 'sun light' while the other side will be totally in darkness and freezing.

So on a statistic analysis of this one exo planet, you are saying earth like planets are beginning to look quite normal? Now I know you're just trolling.

Since when has the earth been tidally locked and orbiting a red 'dwarf'?

You'll be telling us all next, like Professor Vogt, that you're '100 % certain there's life on the planet' too!
Logged

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #59 on: September 30, 2010, 09:01:39 pm »

Evolution only happens where it is needed. 
If you live in a benign climate, with potable water laid on on a regular basis, abundant food there for the taking and somewhere comfy to rest at night, what incentive for change is there?  Change becomes needed when conditions are marginal, and some new aspect of lifestyle that gives an advantage, whether its the use of a stick to get an advantageous supply of termites or the use of a shady leaf to see the fishes better will see some individuals have a better chance of survival.  Those who exhibit traits for better survival will have more descendants than those who don't, and these traits will tend to be passed on.  Not only the trick itself, but the ability to envision further new tricks. 
As humans, we tend to be better at gathering new tricks than most other creatures that we share the planet with.  Whether the tricks that we have learned are ultimately advantageous or a blind alley remains to be seen.
Having lots of neurons only really counts if they get used, but in the case of the apes from a few million years ago, it might have been a change in conditions that forced a change of diet that in turn caused some individuals to start growing bigger brains.  And it could have been a freak mutation triggered by a stray cosmic ray that laid the seed for the exponential rate of change.  Remember that exponential rates start long and slow, we think we are on the steep bit at the moment, but we could be fooling ourselves.  Being able to think does that for you, as well.
Just a random thought - when did opposable thumbs get invented?

Hmmm. Not certain I agree with that Malcolm. Evolution can happen through simple mutation. Now you may argue mutation only happens when needed but simple exposure to radiation can trigger mutation which may result in a change. But that doesnt mean the change happened because it was needed.

The reason bird and or fish didnt evolve nuclear weapons (!?) is mainly due to size but, a whales brain is (I think) the largest of any creature currently alive today. I dont see them building nuclear bombs though. maybe its because they are more peace loving or the fact its very difficult to make a flame underwater. Not that that is impossible mind. But without flame, you're going to find it very difficult in smelting metals etc.

Professor Vogt has today said he's 100% sure there's life on the new planet. Still, seeing as he's also using this new planet to claim there will be billions of earth like planets out there in the goldilocks zone, I think we could take both of his claims with a pinch of salt.
Logged

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #60 on: October 01, 2010, 12:15:02 am »


Its a tidally locked planet orbiting a red dwarf 'star.' With one side tidally locked the planet tidally locked, one side will get all the 'sun light' while the other side will be totally in darkness and freezing.

Life would find this similar to our rotating planet where it's hot on the equator while the poles are freezing.



So on a statistic analysis of this one exo planet, you are saying earth like planets are beginning to look quite normal? Now I know you're just trolling.
Since when has the earth been tidally locked and orbiting a red 'dwarf'?




Let us consider the progress of your arguments so far. You started by telling us that Hot Jupiters in a system meant that no small inner planet could exist ("..smaller terrestrial sized planets, if they existed in the system, would be ejected from that solar system..)

When you were shown to be wrong on that, you conceded that a few rocky earth-sized planets might remain, but that

"..terrestrial planets in the habital zone are virtually non existeant.."

 and you suggested that since lots of Hot Jupiters were being found they must be very common - ignoring the fact that HJs are much easier to find. The gist of your argument became that 'habitable planets' (small, rocky and in the Goldilocks zone) must be very rare since they have not been discovered at the same rate as HJs (even though we know they are going to be hard to find).

Now we have the first 'habitable planet' to be discovered. Earlier than we expected. I presume you agree that it IS a terrestrial-type planet in the habitable zone? I have been unable to find any support anywhere for your novel view that, because it's probably tidally locked around a red dwarf it doesn't count. Stephen Vogt, one of the leaders of the Lick-Carnegie Exoplanet Survey search team is quoted thus:

"Our findings offer a very compelling case for a potentially habitable planet ... The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common."
 
His 'statistical analysis' refers to the time spent looking and the results found. He seems to agree with your earlier comment: "That which is easy to find tends to be the most common.."? If you still hold that view it must be getting hard to support your contention that habitable planets are vanishingly rare...




Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,773
  • Location: Blackpool, Lancs, UK
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #61 on: October 01, 2010, 11:04:50 am »

Quote
Hmmm. Not certain I agree with that Malcolm. Evolution can happen through simple mutation. Now you may argue mutation only happens when needed but simple exposure to radiation can trigger mutation which may result in a change. But that doesnt mean the change happened because it was needed.
If there is an unexploited niche, life, if available, will evolve to fill it.  It could be through stray radiation modifying DNA, it could be dumb luck.  In a reasonably stable system, change is rarely needed, but can happen anyway.  The basic design of sharks has remained pretty constant for many millions of years, but there are variations.

Quote
Life would find this similar to our rotating planet where it's hot on the equator while the poles are freezing.
The presence of a narrow strip that is neither hot enough to melt metal nor so cold that even a Geordie would put a coat on, with neither night nor day nor seasons, would probably not be good for development.  There may be life there, but to quote Spock, "...not as we know it".  It would probably be much like Venus - an acid atmosphere and not tectonic movement.
We have the benefit of a huge satellite which acts as a stabiliser, keeping our tilt fairly constant and giving us seasons.  It also provides tides, which are the marginal conditions needed for setting up the original evolution mechanism.  It also probably helps keep the core temperature high enough so that our water doesn't just drain away and stay there.
We have had several happenings that have shaped life on this planet - the original thud when we gained the moon, then about 259 million years ago when "something" happened to wipe out most of what had evolved, then 65 million years ago when the slate was given a good wipe again.  Just how much of this was essential to our development is really impossible to say, but is we needed all of it, any other planet might well need something similar, and on a similar timescale to arrive at a compatible point.
Being the right sort of size and at the right distance is not the entire story.  There might be millions of such out there, but if it also, for each one, needs a few several million to one chances for life to establish and evolve, there really aren't going to be many.

Quote
"Our findings offer a very compelling case for a potentially habitable planet ... The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common."
I would read this as a coded way of saying "Keep the funding coming, I like having an indoors job with no heavy lifting".  Is that cynical or sceptical?
Logged
"With the right tool, you can break anything" - Garfield

dreadnought72

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,898
  • Wood butcher with ten thumbs
  • Location: Airdrie, Scotland
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #62 on: October 01, 2010, 11:53:39 am »

The presence of a narrow strip that is neither hot enough to melt metal nor so cold that even a Geordie would put a coat on, with neither night nor day nor seasons, would probably not be good for development.

Three points:

Tidal lock on bodies in elliptical orbits (which this planet surely has) always results in a process of libration - a gentle wobble around the lock point. It's the libration of the Moon, for example, that allows us on Earth to see 59% of the lunar surface, over time. For this planet, that "narrow strip" of comfortable living could, therefore, be quite extensive. The presence of an atmosphere - just about a "given", seeing the planet's mass and gravity are high - will somewhat negate the extremes of cold and hot, as heat will be transferred from the hot sun-facing "pole" to the cold "pole".

As to tectonic conditions (and the suggestion of a Venusian-style atmosphere) we have no idea. The star is old, much older than the Sun, so radioactives in the planets will provide less heat than they used to. The stars metallicity is about half that of the Sun's, so again it's likely that these planets are more heavy-metal deficient than our own. That said, this new planet is big - three times the mass of the Earth and perhaps 50% bigger - so it will lose residual heat more slowly than the Earth, and this might mean a "normal" tectonic process is still on-going. We can't say either way that it is or isn't.

Finally: with one data point (the Earth) we really have little idea what is good for development. But some amount of stability is obviously essential - and this planet certainly has that.

Roll on the TPF!

Andy

Logged
Enjoying every minute sailing W9465 Mertensia

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #63 on: October 01, 2010, 12:04:47 pm »


The presence of a narrow strip that is neither hot enough to melt metal nor so cold that even a Geordie would put a coat on, with neither night nor day nor seasons, would probably not be good for development...


If you have an atmosphere the strip would not be narrow. We know nothing about the planets nutation/precession behaviour, which would also widen it. And vegetable life seems to like it here on the equator, where there are no seasons. And nobody knows yet if this planet has a moon, and therefore tides, or even if tides are critically important to biogenesis...

Of course, all this is hypothesising well in advance of the data. All I am pointing out is that the original suggestion that 'habitable-zone' planets are rare or non-existent is not borne out by current evidence, which suggests that they may be quite common. As soon as we obtain the technology needed to identify them we seem to find them.

 I have commented earlier that the prevalence of life is a different question, and one more properly addressed by biochemistry than astronomy, as you suggest in much of your post. Though I am fairly optimistic, given (as I said before) that life started here almost as soon as it could. Intelligent life, however, seems to be another matter.....


(I only saw Dreadnought's comments after I had written the above - but I thought I would submit anyway - in support if nothing else...)
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,773
  • Location: Blackpool, Lancs, UK
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #64 on: October 01, 2010, 05:18:28 pm »

Quote
Intelligent life, however, seems to be another matter.....
Someday, maybe.........

Even equatorial areas have night and day, very sudden night if I recall right.  Usually missed the start of the day. 
In such a situation as the ribbon planet, the atmosphere, if any, might not be useful to any form of life beyond bacteria.
Logged
"With the right tool, you can break anything" - Garfield

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #65 on: October 01, 2010, 05:36:34 pm »


 the atmosphere, if any, might not be useful to any form of life beyond bacteria.


Indeed, it may not be. There may well be no life there at all. The only point I was trying to make was that it is a planet in the habitable zone.

I suspect we will soon have more detailed descriptions of possible surface conditions on such a planet from the exobiologists and others. And I am fairly sure that these better informed descriptions will be shown to be comprehensively wrong when we finally get a probe there in a hundred years or so....
Logged

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #66 on: October 03, 2010, 01:46:48 pm »

Oh and, just so people know what 'earth like' planet means, if the kepler mission had of been launched in another solar system looking towards our system, Venus and possibly even Mars, would be described as 'earth like.'

Venus has a surface temperature hot enough to melt lead and Mars is extremely cold.

As you were.
Logged

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #67 on: October 03, 2010, 01:59:16 pm »

Life would find this similar to our rotating planet where it's hot on the equator while the poles are freezing.


I stopped reading at this laughable assertion. Life on the planet being discussed (or are you changing the parameters of the debate yet again?) ie Gliese 581 g, would not find it similar to our rotating planet.

But dont take my word for it, take New Scientists

"Conditions on the planet would be very different from those on Earth. The host star is a low-mass red dwarf that is just 1 per cent as bright as the sun.

Because it puts out so little light and warmth, its habitable zone lies much closer in than does the sun's. At such tight distances, planets in the zone experience strong gravitational tugs from the star that probably slow their rotation over time, until they become "locked" with one side always facing the star, just as the moon always keeps the same face pointed towards Earth.

That would mean perpetual daylight on one side of the planet and permanent shadow on the other. A first approximation suggests the temperature would be 71 C on the day side and -34 C on the night side, though winds could soften the differences by redistributing heat around the planet."

http://www.newscientist.com/article/dn19519-found-first-rocky-exoplanet-that-could-host-life.html

Of course further investigation would need to be done to confirm the range of temperatures on Gliese 581 g. It could be that the temperature range could be a lot higher but even so, Professor Vogt states the most temperate place would be the terminator.

Mind you, the same professor did state he was "100% certain" this planet has life.
Logged

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #68 on: October 03, 2010, 02:19:17 pm »

Three points:

Tidal lock on bodies in elliptical orbits (which this planet surely has) always results in a process of libration - a gentle wobble around the lock point. It's the libration of the Moon, for example, that allows us on Earth to see 59% of the lunar surface, over time. For this planet, that "narrow strip" of comfortable living could, therefore, be quite extensive. The presence of an atmosphere - just about a "given", seeing the planet's mass and gravity are high - will somewhat negate the extremes of cold and hot, as heat will be transferred from the hot sun-facing "pole" to the cold "pole".

I very much doubt the terminator on this planet would be quite expansive. In fact, I'd say that's an incorrect assertion. The terminator will still represent only a very small part of the planet and an even smaller part of any landmass, even assuming that any landmass runs from pole to pole or part thereof.

Quote
As to tectonic conditions (and the suggestion of a Venusian-style atmosphere) we have no idea. The star is old, much older than the Sun, so radioactives in the planets will provide less heat than they used to. The stars metallicity is about half that of the Sun's, so again it's likely that these planets are more heavy-metal deficient than our own. That said, this new planet is big - three times the mass of the Earth and perhaps 50% bigger - so it will lose residual heat more slowly than the Earth, and this might mean a "normal" tectonic process is still on-going. We can't say either way that it is or isn't.

Gliese is described as a low mass dim red dwarf. As such, it emits something in the order of 1% of the light our sun does. But as you say, tectonic movement is a complete unknown at this point.

Quote
Finally: with one data point (the Earth) we really have little idea what is good for development. But some amount of stability is obviously essential - and this planet certainly has that.

Roll on the TPF!

Andy



I think we have far better examples more easily observable in our own solar system at this time.
Logged

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #69 on: October 03, 2010, 03:25:34 pm »

..I stopped reading at this laughable assertion....

I, in turn, see little point in watching you squirm and try to change the basis of the discussion. You argued that 'habitable planets' were either vanishingly rare or non-existent. "Just to be clear," you said, "..I mean terrestrial sized planets in the habitable zone."

Is this a 'habitable planet' by your definition? The NS article you quote seems to think so:

"Astronomers have found the first alien world that could support life on its surface. It is both at the right distance from its star to potentially harbour liquid water and probably has a rocky composition like Earth..."

The primary point you made, that these planets must be very rare, was supported by your assertion that they were not being found. The same NS article states:

"The discovery suggests habitable planets must be common, with 10 to 20 per cent of red dwarfs and sun-like stars boasting them, the team says. That's because Gliese 581 is one of just nine stars out to its distance that have been searched with high enough precision to reveal a planet in the habitable zone."

Whether life exists on the planet or not is unknown. The surface conditions do not present an insuperable barrier. But current evidence suggests that, when we apply technology which is capable of finding them, these planets will turn out to be quite common, and NOT vanishingly rare...

QED
 
Logged

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #70 on: October 03, 2010, 09:10:36 pm »


That would mean perpetual daylight on one side of the planet and permanent shadow on the other. A first approximation suggests the temperature would be 71 C on the day side and -34 C on the night side, though winds could soften the differences by redistributing heat around the planet."


As a point of interest, the record maximum/minimum temperatures recorded for the Earth are around +60C and -90C. And those are figures measured in the shade with an atmosphere. Estimates for Gliese 581 g seems to be somewhat balmier than here....
Logged

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #71 on: October 13, 2010, 10:23:44 am »

Ironically, in view of the conversations above, I note that at a conference currently running in Torino (The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolution) doubt is being cast on the the existence of Gliese 581 g. Another team has been looking at their data, and say that they cannot confirm the first team's findings. At present it has been demoted to 'unconfirmed'. http://www.space.com/scienceastronomy/doubt-cast-habitable-alien-planet-gliese-581g-101012.html refers.


All these findings are at the limit of what we can do with our current technology (which is improving rapidly as we speak). But most of the data that we need for these findings HAS to be spread over time, so we have to depend on 10 year old data. It is tantalising to have to wait, but wait we must, as I have indicated earlier. I expect that the next several years will bring a wealth of information about smaller planets which we are currently unable to detect...
Logged

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #72 on: October 14, 2010, 07:48:04 pm »

http://www.newscientist.com/article/dn19586-first-lifefriendly-exoplanet-may-not-exist.html

Oh dear! Didnt someone say 'the evidence is growing that earth like planet are quite common' or near as damn it?  %%

I see someone is doing the backstroke already! Never mind!

The current evidence suggests earth like planets are very rare. If any one cares to read the 'Rare Earth' they'll start to grasp why our earth and solar system are tending towards uniqueness.
Logged

dodgy geezer

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,920
  • Location: London
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #73 on: October 15, 2010, 01:12:07 am »

Oh dear! Didnt someone say 'the evidence is growing that earth like planet are quite common' or near as damn it?  %%
I see someone is doing the backstroke already! Never mind!

Yes - the same magazine that you seem to depend upon for all your astronomical stories.


The current evidence suggests earth like planets are very rare....



No it does not. There is inadequate current evidence to pronounce on the 'rare earth' hypothesis, because detecting earth-like planets is at or just beyond the limits of our current observing technology. This episode is a good example of that. 

The report goes on to say: "..Although the Geneva team cannot find evidence for the new planet, they cannot exclude the possibility that Gleise 581 g exists....Steven Vogt... added that the negative result is not entirely unexpected. "I am not overly surprised by this as these are very weak signals..."

I am sure you remember this report on the amplifier problems with Kepler - http://www.universetoday.com/43856/no-earth-sized-planet-hunting-for-kepler-until-2011/ - indicating that habitable-zone planet detection would be very difficult until next year. Though there may be none, it is misleading to suggest that 'the evidence shows them to be rare' until there has been a suitable opportunity to detect a fair number and none are detected. Saying that they are likely to be rare or non-existent at this stage is pure speculation.
Logged

justboatonic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,515
  • Location: Thornton Cleveleys
Re: Kepler mission adds more weight to our solar system not being the norm.
« Reply #74 on: October 15, 2010, 08:06:24 pm »

Yes - the same magazine that you seem to depend upon for all your astronomical stories.


So what's your point here? That I have on occasions referenced NS? Just to show up another of your inaccurate statements or 'spin' in various threads I have referenced other sources. Just because its not the 'science paper' you expect to support a post in a model boat general chat forum. Get a life, mate.

Quote
No it does not. There is inadequate current evidence to pronounce on the 'rare earth' hypothesis, because detecting earth-like planets is at or just beyond the limits of our current observing technology. This episode is a good example of that. 

The report goes on to say: "..Although the Geneva team cannot find evidence for the new planet, they cannot exclude the possibility that Gleise 581 g exists....Steven Vogt... added that the negative result is not entirely unexpected. "I am not overly surprised by this as these are very weak signals..."

I am sure you remember this report on the amplifier problems with Kepler - http://www.universetoday.com/43856/no-earth-sized-planet-hunting-for-kepler-until-2011/ - indicating that habitable-zone planet detection would be very difficult until next year. Though there may be none, it is misleading to suggest that 'the evidence shows them to be rare' until there has been a suitable opportunity to detect a fair number and none are detected. Saying that they are likely to be rare or non-existent at this stage is pure speculation.


You see, there you go again, trying to stifle the debate! A hypothesis is "a proposition, or set of propositions, set forth as an explanation for the occurrence of some specified group of phenomena, either asserted merely as a provisional conjecture to guide investigation (working hypothesis)  or accepted as highly probable in the light of established facts." The Rare Earth fits that description but Im sure you will provide a science paper to argue different though.

Bottom line though, as you constantly appear to forget, is that this is a general chat forum not the astronomical society or whatever you seem to think it should be.

There's no requirement for scientific papers to support ones opinion here. You seem to hang on to the belief that millions of planets like earth (please note I said like earth not earth like) are out there in the Milky Way waiting to be discovered. I think you're going to be disappointed when Kepler's mission results are published. I think there may be the odd ones but they'll be too hot, too cold, in too eccentric an orbit etc.

You may be right. Time will tell but then again, I didnt waste something of the order of nearly 200 computing years (20 headless pc's wasnt it working all day, every day for nearly 10 years?) in the vain hope of finding an ETI signal then, giving up realising at last what a complete waste of time, resources and money the whole thing was. LOL!



 
Logged
Pages: 1 2 [3] 4 5   Go Up