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

yeti101
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

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

M-stars were once thought to be terrible but.... it now looks like they are as good as any. The reason is because atmospheric models show that a tidally locked planet in a habitable zone would circulate its atmosphere.

Not to mention there is research that indicates that habitable zones around M-stars may be wider than G or K stars..



I get why you want to throw out M-stars. Because they make up 80 percent of the galaxy.

reply to post by carewemust


Just curious, but how familiar are you with UFO cases dating back WW2? With this most recent estimate, in my mind, the best explanation for some of the more jaw-dropping cases has become the Extraterrestrial hypothesis. You are looking for images of flying saucers? Well, we have much better - radar, visual, and even physical trace cases. Its becoming harder and harder to say that the Extraterrestrial hypothesis is not the simplest and most thorough explanation.

yeti101
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.

That is not a big if at all. Water is the rule in planet formation. We've seen plenty of water in the star forming regions, in circumstellar disks and even in the spectra of some of the giant planets we've directly imaged.

BTW: If you took all of our Earth's water and put it into a spherical volume, this is how it would look to scale:



In other words, Earth is fairly dry in exoplanetary terms, though it is the 2nd wettest world in our solar system by composition if not by percentage of total volume (Europa is made up of more water by percentage than the Earth).

We know of extrasolar planets with densities that correspond to being completely covered in an ocean many miles deep. There are even studies which suggest those worlds may actually be more numerous in HZs than dryer worlds like the Earth (much study and direct imaging will be needed to know for sure).

Conclusion: Water is not rare, it's likely the rule.

yeti101
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.

Wrong. Even a cursory examination of the literature shows delivery methods. The same way water got on Earth, or Europa, or Ganymede, or Mars or Enceladus in our solar system. Accretion, cometary impacts, etc.

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?

The planets without a Jovian would likely receive MORE water as Jupiter swept up a lot of that material early on.

How would they get that water? Well without a jovian sized world the star itself would have the deepest gravity well and so all that stuff would come hurtling into the "inner planets" of such a system.

They might undergo heavier bombardment as a result, and that -might- mean advanced life would have a hard time (imagine KT level impacts every few million years or so, would we be here?) but that's another matter to whether they would have 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.

It's put there for the same reason gravity is put there. It's an assumption based on the fact that we know most circumstellar disks contain water. Some of them quite a lot. But I guess you missed that part.

OK it might be the case some can have water there but we dont know - its guess work to get a "habitable planet"

When we don't know something, we try to find out. That usually takes new thinking, instruments, perhaps missions. Would you rather we just all stop? Be content to just say, 'yeah well, its hard so we won't bother finding out."?

also those winds lol nothing like earth

Probably true but as they said in Jurassic Park: "Life finds a way."

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.

Ganymede orbits Jupiter and quite likely would have a substantial atmosphere were Jupiter in our sun's HZ. And that's not even Earth size. We see a correlation of moon size to planetary mass somewhat in our solar system. This is a question especially for Super Jupiters which likely would have bigger moons than the ones around our Jupiter. This is why teams like HEK (Hunting Exomoons with Kepler) are fast at work on trying to track down moons in the Kepler data. There are some candidates but nothing is verified yet.

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

Nearly every planetary formation model disagrees with you. These moons are very possible given what we know about planetary formation and migration. But as with most things in this field, there's a lot we still don't know and that's why it is perhaps one of the most dynamic and exciting areas of basic research going on.

Nearly everyone would like to find a moon like Pandora, or Endor, or even Hoth.

If u haven't seen something out Of the ordinary why u talk against it?

H34T533K3R


If u haven't seen something out Of the ordinary why u talk against it?

edit on 11/8/2013 by H34T533K3R because: (no reason given)

No need to quote and misquote and rebuttable this n that..we all together

reply to post by JadeStar

Wrong. Even a cursory examination of the literature shows delivery methods

here's an article which says it might not be so bad. But not for the reasons you state www.space.com...

Would you rather we just all stop? Be content to just say, 'yeah well, its hard so we won't bother finding out."?

no , we have to look but its fun to make predictions. Also when talking about how many habitable planets I like to be conservative. I dont count M stars becuase of the number of problems with them

1. tidal lock
2. tidal forces from the star
3. spectrum of the star
4. massive solar flares and variability of the star

Its difficult to model an "earth-like" planet in these conditions.

Ganymede orbits Jupiter and quite likely would have a substantial atmosphere were Jupiter in our sun's HZ.

Ganymede is 0.025 earth mass. Anything below 0.75 earth mass is too small. The last study done said jupiter size planets cant produce moons big enough . The other option is capturing an earth-size planet but jupiter isn't big enough to do that. I dont know about super jupiters but those are quite rare

so back to kepler: did you crunch the numbers with the more realistic HZ & planet sizes? How many did you come up with?

reply to post by JadeStar


we've measured radius and mass of many planets. Theres a good formula given similar compostion . Sure its not 100% accurate but its pretty good when talking about small earth-like planets

In the kepler papers they produced before launch they described earth size as 0.75-2 earth mass. or up to 1.3 earth radius. You can still find them on their website.

Their latest paper gives the results for planets 1 to 1.4r for a good reason. These are the ones that could be like earth.

We will be discussing this awesome thread on ATS Live tonight.

www.abovetopsecret.com...

zazzafrazz
We will be discussing this awesome thread on ATS Live tonight.

www.abovetopsecret.com...

Zazz you rock!

By the way I found a decent, not too technical introduction to all of this stuff. It strikes a balance between information and methodology (read: match).

It's a little old (2006) but since its just the basics it's worth a read.

The Astrobiology Primer: An Outline of General Knowledge—Version 1, 2006
Abstract: astrobiologyfuture.org...
PDF of Paper itself: astrobiologyfuture.org...

Think of it as like an Astrobiology 001


Also if you just want to get right to a "one-sheet" introduction to habitable planets then read this:

Brief overview about planet habitability:
web.mit.edu...

yeti101
reply to post by JadeStar

 

we've measured radius and mass of many planets. Theres a good formula given similar compostion . Sure its not 100% accurate but its pretty good when talking about small earth-like planets

In the kepler papers they produced before launch they described earth size as 0.75-2 earth mass. or up to 1.3 earth radius. You can still find them on their website.

Their latest paper gives the results for planets 1 to 1.4r for a good reason. These are the ones that could be like earth.

edit on 9-11-2013 by yeti101 because: (no reason given)

Correct. However there is a zone between 1.4 radii and 2.5 radii which are considered Super Earths when their density is that of a rocky world with low mass.

Up to 2.5 radii it is very unlikely that the planet will have a dense Neptunian atmosphere. But again a lot of this has to do with two MAJOR factors and one minor one: Composition. Age of system and Place of planet formation within the circumstellar disk. Or like I like to say ASL - (Age, Situation, Location)

Again 2.5 Earth Radii is the cutoff. And again this depends on composition.

The reason these Super Earths get so much attention is because nothing like them exists in our solar system but there are tons of them in the Kepler data so they provide a large enough sample size that some conclusions can be made about them.

That said there is still tons more to learn about them (giv meh spectra nao plz!) and there are mission proposals like SEE-COAST the Super earth explorer space telescope.
link.springer.com...