The More Earth-Like Planets = The Lesser the Probability of Intelligent Alien Life???

reply to post by JadeStar


A post almost religious in its fervour.

We call them 'habitable zones' (they are only called goldilocks zones by the media.

You call them what you please, and so shall I.

The chance of finding a planet with intelligent life on it is effectively zero because of the size of the volume of space and the distances involved. The work-arounds you offer in your previous posts serve only to highlight how nearly impossible such a feat is. We are capable of none of them; we can barely get a man to the Moon these days.

The problems are not just the technological ones, though these are already, I think, almost insurmountable; the biggest problems are economic. A telescope in solar orbit at a distance 10 times the mean orbit of Pluto? Three light-days out from Earth? You must be joking.

You seem to think that increasing the number of candidate planets in the volume increases your chances. In fact, as the OP says, it reduces them, because you'll have to check out many more, and probably draw many more blanks, before you find one.

We have limited time. I doubt that Western-style technological civilisation will outlast the century.

Luckily there are things which an intelligent species (even if you include ourselves) do that are detectable from interstellar distances.

That's right... apparently. And we've been looking for such traces since the 1970s.

What have we found? Remind me again.

And that doesn't even get onto the subject of exotic physics like warp drives, wormholes...

None of which have been seen to exist, or even shown to be possible in any useful sense.

It's my field of study.

I would say, rather, it is your faith. Despite claims of 'reading the papers and doing the math', all there really is on this subject faith and hope. One in a hundred Earthlike planets is expected to produce a technological civilisation? That's more hope than Pollyanna ever had.

Nothing wrong with faith and hope so long as you recognise them for what they are.

reply to post by H34T533K3R

There are many sightings that have been reported with very credible and multiple witnesses

UFO sightings? No, there haven't. There have been a few — a handful — with sufficient credibility to suggest that something is going on beyond mass hysteria. But it's still mostly mass hysteria, no question.

Besides, you're assuming that UFOs are alien spacecraft. There is not a shred of evidence to substantiate that belief.

UFO sightings are irrelevant to the subject we're discussing here, I'm afraid.

reply to post by JadeStar


well what they've done is jazz their numbers up for the press & public.

They're counting planets that are too big to be called earth size and they're counting planets that are too close to the star. This allows them to arrive at their 22% figure

If you read the actual paper they released that figure is reduce to 4.3%. Quite a diffirence dont you think?

Then we count the viable stars. Its unlikely any earth-like world would survive outside the GHZ so we have about 20% of the total stars in the galaxy reside in the GHZ.

In the GHZ the distribution of G type stars like sol is 1 in 17 which is well below the galactic average. I guess throwing in the early K type will make that ratio better.

crunch the numbers with those stats and see what you get

yeti101
reply to post by JadeStar

 

well what they've done is jazz their numbers up for the press & public.

They're counting planets that are too big to be called earth size and they're counting planets that are too close to the star. This allows them to arrive at their 22% figure

If you read the actual paper they released that figure is reduce to 4.3%. Quite a diffirence dont you think?

Please cite examples of the bolded bit above. Because I've read the paper and they all fall within the conservative estimate of the circumstellar habitable zone.

As for Super Earths. Up to 2.5 radii they're considered earth like. Earthlike does not mean Earth size. You can have slightly bigger and slightly smaller terrestrial planets which models show would be earthlike. Beyond 2.5 radii they're likely to be mini-Neptunes rather than Super Earths.

Only earth and super earth sized planets were considered in the paper.

Then we count the viable stars. Its unlikely any earth-like world would survive outside the GHZ so we have about 20% of the total stars in the galaxy reside in the GHZ.

In the GHZ the distribution of G type stars like sol is 1 in 17 which is well below the galactic average. I guess throwing in the early K type will make that ratio better.

G stars are not the only stars habitable to life, G, K and M (even some F) stars are.

The paper covers only G and K stars.

And the "Galactic Habitable Zone" isn't taken seriously by anyone because there's little evidence to support such a thing exists.

reply to post by JadeStar

Beyond 2.5 radii they're likely to be mini-Neptunes rather than Super Earths.

the term super earth is misleading. They only came up with that name becuase when we got down to detecting 10earth mass planets everyone got excited and decied to make a new name for them. It has nothing to do with them actually being "earth like"

2 papers presented on the live stream stated above 1.6r and its a mini neptune. Even at 1.4r thats still 2.7 earth mass. Above 2 earth mass and the planet will collect too much gas giving it a cloud deck miles thick and no sunlight will reach the surface.

Please cite examples of the bolded bit above. Because I've read the paper and they all fall within the conservative estimate of the circumstellar habitable zone.

the paper reduced the HZ from what they say in the press release. The press release states planets with up to 4x the solar flux of earth. Which is totally insane. With the more realistic HZ in the paper the 22% is reduced to 8.6%

Then when they reduce the number to only include planets from 1 to 1.4r it halves that number ( according to the paper) down to 4.3%

But thats extrapolation as they haven't found any of those yet.

On the GHZ - theres no way earth like planets can survive near the galactic centre or near the outer star forming regions. You cant have all the stars in the galaxy its unrealistic

reply to post by JadeStar


btw forget about M stars they're terrible . Besides the only thing we do know is that earth-like planets are possible around stars like sol. So to be realistic or conservative I think its best only to include those (I'll give you early K also). We need to know the task we face when trying to find one to plan future missions.

wishing that M stars are good goes against all the evidence

reply to post by yeti101

wishing that M stars are good goes against all the evidence

Not so ...

Six percent of red-dwarf stars have habitable, Earth-sized planets, astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) have found. Red dwarfs are the most common stars in our galaxy; about 75 percent of the closest stars are red dwarfs. The closest Earth-like planet could be just 13 light-years away, Harvard astronomer and lead author Courtney Dressing calculated. Since red dwarf stars live much longer than Sun-like stars, this discovery raises the interesting possibility that life on such a planet would be much older and more evolved than life on Earth.
www.dailygalaxy.com...

reply to post by gortex


i have no doubt there will be planets the same size as earth in the HZ of some M stars. I just dont think they will have any complex life or be anything like earth.

M stars will give up their secrets first. Will be interesting to find out what those planets are like my bet is they are dry as a bone, hostile maybe even magma covered.

reply to post by yeti101

I just dont think they will have any complex life or be anything like earth.

That is your belief but it is at odds with current scientific thinking on habitable worlds orbiting Red Dwarfs aided by observations by the Kepler Space Telescope .

“Most of the planets in the Milky Way orbit red dwarfs, a thermostat that makes such planets more clement means we don’t have to look as far to find a habitable planet,” said study co-author Dr Nicolas Cowan from the Northwestern University’s Center for Interdisciplinary Exploration and Research in Astrophysics. The formula for calculating the habitable zone of alien planets has remained much the same for decades. But the formula largely neglects clouds, which exert a major climatic influence
www.sci-news.com...

reply to post by gortex


its hype. Ask Dr Cowen what the effect of tidal locking will have on his habitable planets. Be interested to hear his answer

Then ask what the tidal forces of being so close to the star will do to that planet - major internal and surface disruption (earthquakes) not a good place to build a house. Could even be covered in magma

anyone hyping M stars will be someone in the feild of researching them. They have to dangle the carrot to get funding.

reply to post by yeti101

its hype. Ask Dr Cowen what the effect of tidal locking will have on his habitable planets.

Perhaps you should read the link I provided the answer is there .

Planets in such a tight orbit would eventually become tidally locked with their sun. They would always keep the same side facing the sun, like the moon does toward Earth.

Calculations of the team indicate that the star-facing side of the planet would experience vigorous convection and highly reflective clouds at a point that astronomers call the sub-stellar region. At that location the sun always sits directly overhead, at high noon.

The team’s three-dimensional global calculations determined for the first time the effect of water clouds on the inner edge of the habitable zone. The simulations are similar to the global climate simulations that scientists use to predict Earth climate.

These new simulations show that if there is any surface water on the planet, water clouds result. The simulations further show that cloud behavior has a significant cooling effect on the inner portion of the habitable zone, enabling planets to sustain water on their surfaces much closer to their sun.
www.sci-news.com...

reply to post by gortex


this part

These new simulations show that
if there is any surface water on the planet, water clouds result. The simulations further show that cloud behavior has a significant cooling effect on the inner portion of the habitable zone, enabling planets to sustain water on their surfaces much closer to their sun.

thats a big if. Gortex this is what they do. they create a scenario that if this if that if the other are true then its possible to have a habitable world.

He would need to explain where the water comes from. Also when they say "vigorous convection" we're talking winds of hundreds if not thousands mph = very bad weather. Its hype. I know its not what you want to hear but thats the cold hard truth

They have a vested interest in getting missions to study these planets so they hype stuff up. Its not realistic but they'll do anything to get their missions up and running. Even tell white lies

ok ist not exactly lies but you certainly dont get the whole truth, they bend the scenario to give the outcome they desire

the last lot that modeled earth size worlds did the same thing. They tried so hard to get the surface temps like earth they ended with a cloud deck so thick no sunlight would reach the surface. They never mentioned that to the press though. This is what they do

Would God and Angels be counted as extra-terrestrial intelligent life? Demons? Or extra-dimensional? In any case, there are probably at least thousands of pages of religious texts out there detailing historical contact, for starters, from cultures around the world - Egyptian, Hindu, Judaic, Mayan -

Just a thought, I'm not entirely sure about the details on them.

reply to post by yeti101

I know its not what you want to hear but thats the cold hard truth

All I see from you is unsubstantiated assertions on your beliefs so given the choice of who to listen to I choose the guy with a Ph.D. Astronomy and who specialises in the climate of exoplanets .

I'm a planetary scientist in CIERA at Northwestern University specializing in the climate of exoplanets. Specifically, i construct maps of these distant worlds by monitoring how their brightness and color change with time, exo-cartography.
I'm an instigator of the ExoClimes meetings, which (unsurprisingly!) cover most of the scientific areas that interest me. As a member of the NASA's ExoPAG executive committee, i promote research in exoplanet climate and help map out the landscape of future exoplanet missions.
nickcowan.com...

Best not get started on habitable planets orbiting gas giants as I doubt you accept that possibility either

reply to post by gortex


I would be interested in intelligent life developing in gas giants, at any rate, don't gas giants tend to have moons that are decently inhabitable, even in our own solar system, aren't some of the most inhabitable "planets" actually the moons of gas giants?

reply to post by darkbake


Ganymede is one such Moon if it were orbiting a Star it would be considered a Planet , it is also believed that it has a salt water ocean beneath it's surface that like Europa may be home to life .

Ganymede has a thin oxygen atmosphere – too thin to support life. It is the only satellite in the solar system to have a magnetosphere. Typically found in planets, including Earth and Jupiter, a magnetosphere is a comet-shaped region in which charged particles are trapped or deflected. Ganymede’s magnetosphere is entirely embedded within the magnetosphere of Jupiter
www.space.com...

It is also believed that life could exist in the atmosphere of Gas Giant planets where conditions would be more favourable to living organisms .

reply to post by gortex


"if there's water on the surface" They dont deal with how the water is there , they just put it there like magic. Thats nice but its a major question regarding M stars. If theres no outer jovian in the system how do comets get directed there to supply that water?

if you asked him he would say " my paper isn't about that" . For the purposes of his modelling he just puts it there. OK it might be the case some can have water there but we dont know - its guess work to get a "habitable planet"

also those winds lol nothing like earth

On habitable planets orbiting jovians. You would need to explain how an earth size planet comes to be in that orbit. The only serious study done came to the conclusion that earth size planets were not possible they would all be too small. An earth size planet is too big to be captured by a jovian like Jupiter. Maybe a super jovian? but these are rare.

I'm not holding out for "pandora" planets no. I dont think its realistic

reply to post by JadeStar


Of these 3 data sources:

SIMBAD only allows constrained searches, not true queries. The vey reason I have my own database is so that I'm not constrained in what I decide to search for; all of the data is available. I speak fluent "SQL" (structured query language) and would prefer to author my own queries.

The NASA site is "gone".

The web archive...do they actually have an interface there? The navigation is so far from the "norm" that there seems to be a rather steep learning curve...not sure I have the time. Also, it appears that what they have are a collection of "web captures", which is not at all what I'd be looking for.

The search for data continues

Just want to chime in with a thought. Just on our planet there are billions of creatures living through out their lives without being aware the existence of human.

yeti101
reply to post by JadeStar

 

Beyond 2.5 radii they're likely to be mini-Neptunes rather than Super Earths.

the term super earth is misleading. They only came up with that name becuase when we got down to detecting 10earth mass planets everyone got excited and decied to make a new name for them. It has nothing to do with them actually being "earth like"

That's not true at all. No one I know in the field would call a 10 earth mass planet a Super Earth. That's a slightly less massive Neptune!

2 papers presented on the live stream stated above 1.6r and its a mini neptune.

It was 2.6. And those 2 papers were based on a lot of "ifs" which need to be clarified. The speakers said as much and urged that further observations will be needed to verify that. Do you want me to go into the technical reasons why that is?

Even at 1.4r thats still 2.7 earth mass.

BINT!

Wrongo!

Radii has nothing to do with Mass. If you had watched most of Monday-Wednesday you'd have seen paper after paper which basically spelled that out. You can not -reliably- derive mass from radii, nor can you derive radii from mass (say in Radial Velocity surveys).

You -can= derive mass from TTVs and you can use models to fit that with the observed radii but....there are a lot of buts

Above 2 earth mass and the planet will collect too much gas giving it a cloud deck miles thick and no sunlight will reach the surface.

Bint. Wrong again.

That would depend upon the makeup of the circumstellar disk, where in it the planet formed and core density while the accretion process happened.

Again, there were plenty of papers presented that spelled that out.

the paper reduced the HZ from what they say in the press release. The press release states planets with up to 4x the solar flux of earth. Which is totally insane. With the more realistic HZ in the paper the 22% is reduced to 8.6%

Stellar flux is NOT the same as solar flux. It varies by star spectral type, luminosity, etc. It could be that what you read reported confused the two, which lead you to that conclusion.

Then when they reduce the number to only include planets from 1 to 1.4r it halves that number ( according to the paper) down to 4.3%

But thats extrapolation as they haven't found any of those yet.

Yes they have... Would you like a list?

Here's a nifty chart:

On the GHZ - theres no way earth like planets can survive near the galactic centre or near the outer star forming regions. You cant have all the stars in the galaxy its unrealistic

edit on 8-11-2013 by yeti101 because: (no reason given)

Well duh....

But those stars are not the G and K stars which the study covers. Those stars aren't even main sequence stars. They are irrelevant. That's why no one talks about a Galactic Habitable Zone.

Everyone knows Population I near the Galactic center are stars are unlikely to support life.

Basically the majority of the disk of the Milky Way is a "Galactic Habitable Zone". No one calls it the GHZ. They just call it the disk.

BTW you might like this chart. It is basically everything that has to do with all the factors which might make a planet Earthlike and how they relate to each other. The stuff in black is kinda important.

files.abovetopsecret.com...

edit on 8-11-2013 by JadeStar because: (no reason given)