Temperatures on fictional planets

[willpittenger]

Why do so many SciFi storied (notably Star Trek) assume that the temperature for a planet is just one value?&nbsp; The Enterprise would enter orbit around some planet and Data announces the surface temperature is X&deg;.&nbsp; The correct temperature would vary by location and time of day. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[PistolPete]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Why do so many SciFi storied (notably Star Trek) assume that the temperature for a planet is just one value?&nbsp; The Enterprise would enter orbit around some planet and Data announces the surface temperature is X&deg;.&nbsp; The correct temperature would vary by location and time of day. <br /> Posted by willpittenger</DIV></p><p>Because the show is only 42 minutes long without commercials.&nbsp; A complete survey of an entire planet's climatological data could take the better portion of a week and would get very poor ratings.&nbsp;</p> <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>

 

[willpittenger]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Because the show is only 42 minutes long without commercials.&nbsp; A complete survey of an entire planet's climatological data could take the better portion of a week and would get very poor ratings.</p><p>Posted by PistolPete</DIV>Still, they could pay better attention to facts.&nbsp; Slightly changing the wording to include "at the landing site" would help. </p> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[kelvinzero]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Because the show is only 42 minutes long without commercials.&nbsp; A complete survey of an entire planet's climatological data could take the better portion of a week and would get very poor ratings.&nbsp; <br />Posted by PistolPete</DIV></p><p>&nbsp;This is exactly right, so the question then becomes "Why does most SF on TV revolve around the one-planet-per-episode format". I think it is convenient because it lets each script writer throw away the world of the last episode and start from scratch. Of course since that world exists for just one episode it will have pretty much just one setting.</p><p>&nbsp;I actually feel a hardSF solar system would make more sense for this format. This solar system could hold many thousands of ONeil-style colonies, Each would reproduce just one natural habitat from earth. They could even populate them with species that were millions of years extinct on earth.</p><p>&nbsp;Although a colony might be only 10km in radius, a 10km cubic area is vast. It could be divided into a thousand 10-meter high levels, giving 100,000 square km of&nbsp;surface area.&nbsp;If these levels were layed out in a snailshell pattern, and for some reason you could not travel directly between levels, then you would have to travel through something like 10,000km of habitat to get from the edge to the core.</p><p>Cultures are also&nbsp;rather simplistic in SF for the same reasons discussed above, and this would also make more sense in the hardSF-style solarsystem for pretty much the same reasons.&nbsp;Each would consist of a population that had come together for just one reason, often cultural.</p><p>A hardSF solar system filled with humanoids of rougly the same tech-level also makes more sense than a galaxy of the same. If we ever produce a civilisation of this size it is entirely reasonable that each colony could have genetically engineered themselves towards some practical or entirely asthetic ideal of their own.</p><p>&nbsp;</p>

 

[yevaud]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Why do so many SciFi storied (notably Star Trek) assume that the temperature for a planet is just one value?&nbsp; The Enterprise would enter orbit around some planet and Data announces the surface temperature is X&deg;.&nbsp; The correct temperature would vary by location and time of day. </p><p> Posted by <em>willpittenger</em></DIV><br /></p><p>Generally, Planetary Scientists determine the <em>Average</em> global temperature, using (as best I recollect it) the following formula:</p><p>Tp = (1-A)/Pi16DR^2).&nbsp; That's a global average, assuming a sperical shape, the distance from the primary, and taking into acvcount the global Bond Albedo.</p><p>[I <em>think</em> I remembered that formula correctly.&nbsp; It's been years since I have had to use it.] </p> <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Generally, Planetary Scientists determine the Average global temperature, using (as best I recollect it) the following formula:Tp = (1-A)/Pi16DR^2).&nbsp; That's a global average, assuming a sperical shape, the distance from the primary, and taking into acvcount the global Bond Albedo.[I think I remembered that formula correctly.&nbsp; It's been years since I have had to use it.] <br />Posted by yevaud</DIV><br />&nbsp;How about</p><p>Tp = [(S0/4)(1-a)/s]^1/4</p><p>where Tp is the average planetary temperature (K), S0 is the "solar flux" at the planet, a is the albedo and s is the Stefan-Boltzmann constant ?&nbsp; S0 can be calculated from the total luminosity of the star by S0 = L0/(4*pi*d^2) where L0 is the total out put of the star in watts and d is the distance to the planet surface from the center of the star.</p> <div class="Discussion_UserSignature"> </div>

 

[yevaud]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;How aboutTp = [(S0/4)(1-a)/s]^1/4where Tp is the average planetary temperature (K), S0 is the "solar flux" at the planet, a is the albedo and s is the Stefan-Boltzmann constant ?&nbsp; S0 can be calculated from the total luminosity of the star by S0 = L0/(4*pi*d^2) where L0 is the total out put of the star in watts and d is the distance to the planet surface from the center of the star. <br /> </p><p>Posted by <em>DrRocket</em></DIV></p><p>Thank you (mutter mutter, imperfect memory).&nbsp; However, there was a part (the poorly recollected 16dR^2), which took into account that this is a spherical body?&nbsp; I seem to remember that as a part of the equation.&nbsp;</p><p>[Geez, I should really pick up some of my old texts and re-read these things]&nbsp;</p> <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[eburacum45]

On some planets, like Venus for instance, the temperature would be fairly even because of the superrotating atmosphere; there the temperature varies with height more than with latitude IIRC. <div class="Discussion_UserSignature"> <p>---------------------------------------------------------------</p><p>http://orionsarm.com  http://thestarlark.blogspot.com/</p> </div>

 

[yevaud]

Actually, disregard that, Doc.&nbsp; I did go refer to the old textx, and reviewed the entire (multiple step) equation(s). <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[willpittenger]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Generally, Planetary Scientists determine the Average global temperature, using (as best I recollect it) the following formula:Tp = (1-A)/Pi16DR^2).&nbsp; That's a global average, assuming a sperical shape, the distance from the primary, and taking into acvcount the global Bond Albedo.[I think I remembered that formula correctly.&nbsp; It's been years since I have had to use it.]</p><p>Posted by yevaud</DIV><br />To me, that is as useful as stating the average temperature for a city.&nbsp; Sure, it might read a nice 70&deg;F in a place like Peoria, IL.&nbsp; But before you head here, be aware that it can be as hot as 120&deg;F (heat index) and as cold as -20&deg;F (wind chill).&nbsp; So would that average temperature tell you what to wear here? </p> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[yevaud]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So would that average temperature tell you what to wear here? </p><p> Posted by <em>willpittenger</em></DIV></p><p>No, I'm afraid not.&nbsp; As stated, it is the <em>averaged</em> global temperature. </p> <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>No, I'm afraid not.&nbsp; As stated, it is the averaged global temperature. <br />Posted by yevaud</DIV></p><p>&nbsp;I used to have an office with a very pleasant average temperature.&nbsp;&nbsp;It was virtually uninhabitable.<br /></p> <div class="Discussion_UserSignature"> </div>

 

[yevaud]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;I used to have an office with a very pleasant average temperature.&nbsp;&nbsp;It was virtually uninhabitable. </p><p> Posted by <em>DrRocket</em></DIV></p><p>A low of -20 C and a high of 35 C?&nbsp; </p><p><br /> <img src="http://sitelife.space.com/ver1.0/Content/images/store/4/7/f437adf7-332b-49ad-a767-0e65238e91d4.Medium.gif" alt="" /><br />&nbsp;</p> <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>A low of -20 C and a high of 35 C?&nbsp; &nbsp; <br />Posted by yevaud</DIV><br /><br />You got it.&nbsp; About 6 months of each.</p> <div class="Discussion_UserSignature"> </div>