Gravity and Rocky worlds

[one_billy]

I'm just wondering about the day we go planet hunting.And we find a Rocky planet the size of Jupiter.Is there any information on gravity and life.<br />Rephrased-Could the gravity of a planet be so strong it chokes off the possibility of life.Is there a ceiling.Is there a scale. <div class="Discussion_UserSignature"> </div>

 

[Saiph]

well...you won't find a "rocky" planet the size of jupiter. At that mass, gases won't escape, and so even if the rocky portion is the size of jupiter, the huge hydrogen & helium atmosphere will easily mask it and look like a giant Jovian planet. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[igorsboss]

Life forms can overcome gravity by using bouyancy, using Archimedes' principle that the bouyant force equals the weight of the displaced fluid.<br /><br />Rocky worlds are those which have a surface where solid meets gas. Gasses are not dense enough to offer significant bouancy support, so the rocky world life forms must either support themselves, or resemble a puddle.<br /><br />Liquid H20, however, gives plenty of bouyant force. Life forms can swim.<br /><br />Archimedes' principle remains true in all gravity fields. So, even if you had a gas giant, if there was a liquid H20 layer, life could possibly survive there without getting squished (down) by the gravity or (inwardly) by the pressure.<br /><br />However, under extreme pressure, liquid water can become extremely hot, without boiling. Life might have problems with extreme temperatures.<br /><br />Although we don't yet know what the limits are today, this is yet another reason why liquid H2O remains the key to life.