The continuously habitable zone: Earth's life sustainability

Amendment:

'Hot Jupiters' are thought to have "formed farther out and migrated inward via gravitational torques with a massive gas disk (Lin et al., 1996)" (Lin, Bodenheimer, & Richardson, 1996, p. 256).

Since "roughly one-third of the giant planets discovered to date outside the Solar System have orbits within 0.5 astronomical units (AU) of their central stars (exoplanets(dot)org)" (Lin, Bodenheimer, & Richardson, 1996, p. 256), then I should note that whatever the likelihood is of terrestrial planets forming is, there may be roughly a 1 in 3 chance that their formation will be disrupted by a hot Jupiter moving in.

However, I should also note that "if a giant planet forms and migrates quickly, the planetesimal population has time to re-generate in the lifetime of the disk and terrestrial planets may form (Armitage (2003)" (Lin, Bodenheimer, & Richardson, 1996, p. 256). And in some cases, it seems that "potentially habitable planets with orbits in the habitable zone and substantial water contents can form in such conditions," and that their obliquity "would likely be stable over long timescales (Atobe et al., 2004)" (Lin, Bodenheimer, & Richardson, 1996, p. 262).

All in all, my argument is not significantly affected, since, even with the adjustment, we are still dealing with hundreds of billions of stars in our galaxy and tens of sextillions of stars in the observable universe.


Raymond, S.N., Quinn, T. & Lunine, J.I. (2005). The formation and habitability of terrestrial planets in the presence of close-in giant planets. Icarus, 177(1):256-263.

Lin, D.N.C., Bodenheimer, P., Richardson, D.C., 1996. Orbital migration of the planetary companion of 51 Pegasi to its present location. Nature 380, 606--607.

Armitage, P.J., 2003. A reduced efficiency of terrestrial planet formation following giant planet migration. Astrophys. J. 582, L47--L50.

Atobe, K., Ida, S., Ito, T., 2004. Obliquity variations of terrestrial planets in habitable zones. Icarus 168, 223--236.




References:

Nixon, C. (2006). ASTR 330: The Solar System. Retrieved April 26, 2008, from Department of Astronomy University of Maryland Web site: http://www.astro.umd.edu/~nixon/ASTR330fall06/Lecture25-Formation2.ppt

Franco, L. M. (1996, November 20). The Solar System Astronomy 100 Fall 1996 Indiana University Northwest. Retrieved April 27, 2008, from The University of Chicago Department of Astronomy and Astrophysics Web site: http://astro.uchicago.edu/home/web/lucia/a100/lectures/comet.html

Franck, S., von Bloh, W., Bounama, C., Steffen, M., Schönberner, D., & Schellnhuber, H.-J. (2002). Habitable zones and the number of Gaia's sisters. In: B. Montesinos, Gimenez, A., & Guinan, E. F. (eds.), Proceedings of the Second Granada Workshop "The Evolving Sun and its Influence on Planetary Environments", ASP Conf. Series 269, 261-272.
http://www.pik-potsdam.de/PLACES/publications/datenfiles/ASP_269.pdf

Kasting, J. F., Whitmire, D. P., & Reynolds, R. T. (1993). Habitable zones around main sequence stars. Icarus. 101, 108-28.
http://www.geosc.psu.edu/~kasting/PersonalPage/Pdf/Icarus_93.pdf

Freedman, R., & William, K. (2002). Universe (3rd Edition). New York: W.H. Freeman and Company.

Purdy, M. (2003, August 4). 70,000,000,000,000,000,000,000 Stars in the Sky. Retrieved April 30, 2008, from The JHU Gazette Web site: http://jhu.edu/~gazette/2003/04aug03/04stars.html

Category:

Science & Technology

Tags:

• fine-tuning
• argument
• continuously
• habitable
• zone
• sustain
• life

[unbreakable2008]

"If you continue to ignore my points (even while quoting them, ironically enough), then I would prefer that you leave." Oh the words of someone who is somewhat intelligent but thinks he knows everything..... lol, you are not mentally equipt to handle people who push you mentally around and this will be your downfall! You have a superiority complex, better drop it. Signs of a loser. Dont worry, you bore me... I just responded to have fun. Have fun talking to yourself! :-)

[SecularAstronomer]

@unbreakable2008

“Oh the words of someone who is somewhat intelligent but thinks he knows everything..... lol.”

Of course I don’t know even nearly everything. This is an emotional response.

“You are not mentally [equipped] to handle people who push you mentally around and this will be your downfall! You have a superiority complex, better drop it.”

This is grandiose rhetoric. I gave a detailed response to your points. Please address them.

[SecularAstronomer]

“Signs of a loser.”

You are being petty. Don’t let anger get the better of you.

“Don’t worry, you bore me... I just responded to have fun. Have fun talking to yourself! :-)”

You just accused me of having a superiority complex and now you are condescending to me? Again, please just address my points.

[SecularAstronomer]

I shall summarize my points, for ease of response:

I agree that life can be far more diverse and commonplace than the one example of Earth and its inhabitants. I agree with much of what you say about life and its possible ranges, and I only use the liquid water criterion to dispel the argument life can only be here on earth (one you also disagree with) by establishing a conservative estimate based on the observed example of earth.

[unbreakable2008]

Its ok man, just pulling you leg.... I actually like your videos, i just wanted to see how you would react to different opinions. Lets call it a social experiment. I have been in your shoes many times, saying things in a calm and validated way within parameters that I define, then comes a nutcase saying stuff out of the blue. You have get used to this my friend... there are a lot of people out there who do not think or have different backgrounds... you cannot persuade them all. Be well...-K

[SecularAstronomer]

It is clear that you either don’t know what a conservative estimate and lower bound is, or you didn’t put any thought whatsoever into what I said. If you continue to ignore my points (even while quoting them, ironically enough), then I would prefer that you leave.

[SecularAstronomer]

“Your assumptions are the problem. Think out of the box.”

One always works tentatively from an observable starting point, so as to establish a baseline. This is basic science. I obviously don’t cling to the parameters of the analysis. “Thinking outside the box” is what one does after departing from the baseline. This video only establishes the baseline so as to refute an invalid argument that you also disagree with. You would see this if only you would cease being so pigheaded about the mater.

[SecularAstronomer]

“You must stop motormouthing and start thinking differently for a while.”

Again, I agreed with your statements about the plausibility of diversity and range. Please pay attention.

“…you are like a text book of the 1900s. Reminds me small minds.”

I established a vital baseline from which further inquiry can be made. Your failure to grasp this reminds me of my many discussions with the scientifically illiterate.

[SecularAstronomer]

@unbreakable2008

“Since the number of planets are virtually unlimited you probably have many ways of forming life, that will be different from our own…”

I already agreed with this. Please pay attention.

“You have only ONE example to go by, and that is earth. Extrapolating from one example to ALL the frikin universe is non [sequitur].”

Did you even read what I typed? Extrapolating from a baseline establishes a lower bound. Do you not understand such basic scientific terminology?

[unbreakable2008]

@SecularAstronomer "Again, I was conservative in using the liquid water criterion, and did so for the purpose of generating a lower bound." Your assumptions are the problem. Think out of the box. I can tell you this that is a certainty. The universe is not stranger than you imagine, its stranger than you CAN imagine. --Arthur C. Clarke. While I understand your need to explain this information, it can be found on many documentaries and books. I ALREADY KNOW what you are saying but its not enough