Post by creature386 on Feb 23, 2013 17:34:30 GMT 5
That is a topic, where I have already discussed about on many forums, but I think it belongs in a life forum.
The existence of possible extraterrestrial life was a subject, what was discussed in literature and it was subject of some documentries. I have posted some information about that on carnivoraforum, in a therad, where the member chicxulub has shown a solar system, he has created (what I viewed as GREAT work, you can read it here: carnivoraforum.com/single/?p=8373357&t=9707882 ).
Roy Mash (1992) has written a paper about this subject:
"BIG NUMBERS AND INDUCTION IN THE CASE FOR EXTRATERRESTRIAL INTELLIGENCE"
I found the following quote interessting:
Analysis shows that . . . an open universe must be infinite in extent, with an infinite number of galaxies, an infinite number of stars, and an infinite number of planets. In an infinite universe, any event which has a finite probability-no matter how small-of occurring on a single given planet must inevitably occur on some planet. In fact, such an event must occur on an infinite number of planets." (Hart 1982, 163)
An infinite universe?
If he is right, there are for sure planets other planets with lifeforms (like he stated, it would aswell be an infinite number).
Altough, I honestly think that quote was a bit fundamentalistic (but I'm a layman at that subject).
There is other information, which I have aswell shown on carnivora (and another forum). It shows the habitable zone and possible worlds with extraterrestrial live (depending on special conditions). It aswell stated that there are 200 planets who can be viewed as candidates (what is still a lot). I have already written a summary about that on carnivora, which I will quote, because I find it very interessting, so i want to share it with you:
Let's sum this up:
They talk about planets, who could possibly be inhabited by lifeforms. When searching, they often find gas-gigants, due to their size, but they also find rocky planets of course. These aren't easy to find, the probability to find them in an orbit is less than 0,5%, but they've found lot's of planets, who are 5 times as large as the earth. Now, these planets need the right conditions. One is of course liquid water, another is being in the right distance to the sun, otherwise it ould be too hot or too cold, so the water can't be liquid (Source: F. Kasting, D. P. Whitmire, R. T. Reynolds, Icarus 101, 108 (1993).
The critical limit for heat is 374°C. In conditions like we have them in our solar system, planets could be covered 20-50% in ice. These would be waterworlds, with up to 100 km deep spots.
Here a simulation:
As you see in the text, they've found earth-sized planets, in the near of red dwarf stars, these are not easy to find, because red dwarf stars are less bright than other stars. They've also written a lot about the methods which they use for searching, however, they don't know a lot about the habitability of red dwarf stars you can see here, what was written about the habitable zone:
Red dwarf stars are acceptable stars for planets with live, but their UV rays are a problem for the atmosphare of the planet (Source). Regarding the Mars, it lost it's atmosphere, because it's gravity was too low to keep an atmosphere, due to it's core.
It was also stated that the Venus is within the habitable one, but they don't know if it has water.
Here the paper stated how water can be lost:
Water is also more likely to be lost because the speed of impacts during accretion is higher, and the high or bital angular momentum of any water-rich plane tesimals from further out in the system would prevent them from reaching the planet.
(Sources: ]. ]. Lissauer, Astrophys. ). 660, L149 (2007). and S. N. Raymond, T. Quinn, j. |. Lunine, Icarus 168, 1 (2004).
Planet forming disks can aswell play a role. When the carbon/oxygen ratio is too high, water can be absent. Instead, we would have oceans and an atmosphere made of hydro-carbonates.
That was my summary. I should maybe mention, that they want to use the "James Webb Space Telescope" this year.
I hope this gave some inspiration. When creating my worlds, I may create a hydro-carbonate planet, but first of all, I have to think of if some kind of life could live there, according to the paper, such a planet would be comparable with the moon "titan" (tough we would have to replace the nitrogen with hydro-carbonates....).
Making my planets will take a lot of time for me, I have to finish my future world at first, I only have the future india so far, that's not a lot (I wanted 12 future worlds and I only have one...).
With 200 possible candidates, I find it likely that at least one of them includes live, it would be unlikely if our planet was the only supporter of live.
Tough it could be very different.
In another forum, a user has listed characteristics of other solar systems, or planets, which could affect live and I think they are relevant here:
-moons determine how big plants can grow, if you can talk acoustically and stabilise the atmosphere. They also can make storms and destroy marine life, before it appears.
-size and color of the sun determine the color of plants
-asteroids and vulcanos can cause mass extinctons, who force evolution to keep going on
-the gravity determines how muscular the animals can be and what's their maximum size
-mass extinction caused trough sudden vulcano erruptions, climate change or comets are not to be forgotten.
Any opinions?
P.S. I will write a blog entry on carnivora about that probably.
The existence of possible extraterrestrial life was a subject, what was discussed in literature and it was subject of some documentries. I have posted some information about that on carnivoraforum, in a therad, where the member chicxulub has shown a solar system, he has created (what I viewed as GREAT work, you can read it here: carnivoraforum.com/single/?p=8373357&t=9707882 ).
Roy Mash (1992) has written a paper about this subject:
"BIG NUMBERS AND INDUCTION IN THE CASE FOR EXTRATERRESTRIAL INTELLIGENCE"
I found the following quote interessting:
Analysis shows that . . . an open universe must be infinite in extent, with an infinite number of galaxies, an infinite number of stars, and an infinite number of planets. In an infinite universe, any event which has a finite probability-no matter how small-of occurring on a single given planet must inevitably occur on some planet. In fact, such an event must occur on an infinite number of planets." (Hart 1982, 163)
An infinite universe?
If he is right, there are for sure planets other planets with lifeforms (like he stated, it would aswell be an infinite number).
Altough, I honestly think that quote was a bit fundamentalistic (but I'm a layman at that subject).
There is other information, which I have aswell shown on carnivora (and another forum). It shows the habitable zone and possible worlds with extraterrestrial live (depending on special conditions). It aswell stated that there are 200 planets who can be viewed as candidates (what is still a lot). I have already written a summary about that on carnivora, which I will quote, because I find it very interessting, so i want to share it with you:
EDIT: He could have exaggerated, but there are 200 planets which are believed to be possible supporters of life:
www.jstor.org/stable/pdfplus/20048571.pdf
BTW: You can use this paper to look at the criteria for such planets to correct your system.
www.jstor.org/stable/pdfplus/20048571.pdf
BTW: You can use this paper to look at the criteria for such planets to correct your system.
Let's sum this up:
They talk about planets, who could possibly be inhabited by lifeforms. When searching, they often find gas-gigants, due to their size, but they also find rocky planets of course. These aren't easy to find, the probability to find them in an orbit is less than 0,5%, but they've found lot's of planets, who are 5 times as large as the earth. Now, these planets need the right conditions. One is of course liquid water, another is being in the right distance to the sun, otherwise it ould be too hot or too cold, so the water can't be liquid (Source: F. Kasting, D. P. Whitmire, R. T. Reynolds, Icarus 101, 108 (1993).
The critical limit for heat is 374°C. In conditions like we have them in our solar system, planets could be covered 20-50% in ice. These would be waterworlds, with up to 100 km deep spots.
Here a simulation:
As you see in the text, they've found earth-sized planets, in the near of red dwarf stars, these are not easy to find, because red dwarf stars are less bright than other stars. They've also written a lot about the methods which they use for searching, however, they don't know a lot about the habitability of red dwarf stars you can see here, what was written about the habitable zone:
Red dwarf stars are acceptable stars for planets with live, but their UV rays are a problem for the atmosphare of the planet (Source). Regarding the Mars, it lost it's atmosphere, because it's gravity was too low to keep an atmosphere, due to it's core.
It was also stated that the Venus is within the habitable one, but they don't know if it has water.
Here the paper stated how water can be lost:
Water is also more likely to be lost because the speed of impacts during accretion is higher, and the high or bital angular momentum of any water-rich plane tesimals from further out in the system would prevent them from reaching the planet.
(Sources: ]. ]. Lissauer, Astrophys. ). 660, L149 (2007). and S. N. Raymond, T. Quinn, j. |. Lunine, Icarus 168, 1 (2004).
Planet forming disks can aswell play a role. When the carbon/oxygen ratio is too high, water can be absent. Instead, we would have oceans and an atmosphere made of hydro-carbonates.
That was my summary. I should maybe mention, that they want to use the "James Webb Space Telescope" this year.
I hope this gave some inspiration. When creating my worlds, I may create a hydro-carbonate planet, but first of all, I have to think of if some kind of life could live there, according to the paper, such a planet would be comparable with the moon "titan" (tough we would have to replace the nitrogen with hydro-carbonates....).
Making my planets will take a lot of time for me, I have to finish my future world at first, I only have the future india so far, that's not a lot (I wanted 12 future worlds and I only have one...).
With 200 possible candidates, I find it likely that at least one of them includes live, it would be unlikely if our planet was the only supporter of live.
Tough it could be very different.
In another forum, a user has listed characteristics of other solar systems, or planets, which could affect live and I think they are relevant here:
-moons determine how big plants can grow, if you can talk acoustically and stabilise the atmosphere. They also can make storms and destroy marine life, before it appears.
-size and color of the sun determine the color of plants
-asteroids and vulcanos can cause mass extinctons, who force evolution to keep going on
-the gravity determines how muscular the animals can be and what's their maximum size
-mass extinction caused trough sudden vulcano erruptions, climate change or comets are not to be forgotten.
Any opinions?
P.S. I will write a blog entry on carnivora about that probably.
