Adonai888 wrote SIZE AND GRAVITY: There is a range for the size of a planet and it gravity which supports life and it is small. A planet the size of Jupiter would have gravity that would crush any life form, and any high order carbon molecules, out of existence.
This fails on so many levels it is mind boggling. Adonai, Jupiter is a gas giant. The gravity at the outer edges of Jupiter’s gaseous envelope is minuscule compared with the crushing gravity at Jupiter’s center. Pick up a used astronomy textbook at your local bookstore and read it. You’ll also learn, if you care, that Jupiter and Saturn have moons which could harbor life.
The effective gravity of jupiter is meaningless to the argument. Jupiter has just been mentioned to give a example.
While it is true that larger stars burn out faster than smaller ones, stars smaller than the Sun can and do have planetary systems, and they can also have a Goldilocks Zone capable of supporting life. Where did you come up with the line about small stars not being likely to form planetary systems?
stars with less than half of Sol’s mass (e.g., smaller spectral type M dwarfs like Proxima Centauri) are more likely to tidally lock planets that are orbiting close enough to have liquid water on their surface too quickly, before life can develop (Peale, 1977). Tidally locking (or synchronous rotation of the star and planet) may eventually cause the destruction of a life-sustaining atmosphere through condensation on the cold, perpetually dark side of the planet. Moreover, most M-type red dwarf stars would tend to sterilize life on a close-orbiting Earth-type planet regularly with large stellar flares. Therefore, NASA’s proposed Kepler Mission will search for habitable planets at nearby main sequence stars that are less massive than spectral type A but more massive than type M—dwarf stars of types F, G, and K. However, since low-mass M- and K-type stars so numerous, some astronomers and planetary scientists are continuing to model low-mass stars and possible planetary environments that may be potentially suitable for Earth-type plant and animal life, as well as for microbes (Helmut Hammer, 2007; Tarter et al, 2007; Scalo et al, 2007; Khodachenko et al, 2007; and Grenfell et al, 2007; and Kiang et al, 2007). [More discussion is available on the potential habitability of brown dwarfs and white dwarfs.]
VOLCANIC ACTIVITY: Volcanic activity is responsible for bringing heaver elements and gasses to the surface, as well as oxygen.
Volcanic activity does not bring oxygen to the surface. Other planets and moons in our solar system show signs of past volcanic activity, and some even have current volcanic activity.
The researchers suggest that mixture of gases and lavas produced by submarine volcanoes scrubbed oxygen from the atmosphere and bound it into oxygen-containing minerals.When terrestrial volcanoes began to dominate, oxygen levels increased.
The change over time caused an atmospheric shift from oxygen-free to oxygen-rich, the researchers argue, with profound implications for life on the planet.
The moon early in its existence also shielded the earth from bombardment by meteor showers that were devastating.
Wrong again. Google “earth heavy bombardment.”
Edit: corrected a typo
i give you that.