re: That seems high. Jupiter is something like 2.3-2.4 with over 300 times the mass of Earth.

Space/Science » in reply to That seems high. Jupiter is something like 2.3-2.4 with over 300 times the mass of Earth.

re: That seems high. Jupiter is something like 2.3-2.4 with over 300 times the mass of Earth.

ER — 4/25/2007 4:59:18 PM (archived)

Surface gravity increases linearly with the mass, and as the inverse square of the radius, so the calculation is much more sensitive to radius than mass.

The whole thread (70 posts)

Earth-like planet, with water, around red dwarf Gliese 581? - REB - 4/24/2007 7:31:46 PM
- Are we *sure* it'd have volatiles? - dtb - 4/26/2007 1:13:42 PM
  - No such thing as sure - nick hoffman - 4/26/2007 11:37:36 PM
- It's actually has a diameter 50% larger than our world. - Jacob Samorodin - 4/25/2007 11:16:43 PM
  - re: Would the absense of a magnetic field be as catastrophic to the atmosphere of a red-dwarf planetary system? - The Artist formerly known as Scott Evil - 4/26/2007 3:15:47 AM
    - Solar wind - nick hoffman - 4/26/2007 9:53:47 AM
      - re: Solar wind - Joe P. - 4/26/2007 4:49:47 PM
        
        "day" and "year" - nick hoffman - 4/26/2007 11:47:47 PM
      - very interesting... Now we need a imaging telescope that can tell us more! - The Artist formerly known as Scott Evil - 4/26/2007 1:40:37 PM
- re: The discoverer - Raoul - 4/25/2007 6:24:36 AM
- Two interesting facts... - TB - 4/25/2007 6:12:00 AM
- Couple of questions: - TB - 4/25/2007 5:46:25 AM
  - re: Couple of questions: - REB - 4/25/2007 1:37:28 PM
    - Splitting Hairs - 3 days per 2 years - M.A.E. - 4/25/2007 9:06:37 PM
      - Who needs an atmosphere? - nick hoffman - 4/25/2007 11:10:46 PM
        
        Good point but - M.A.E. - 4/26/2007 2:31:25 AM
        
        re: Good point but - Excellent points by both of you (MAE & Nick). - Marcia - 4/26/2007 8:44:42 PM
    - re: Couple of questions: - Raoul - 4/25/2007 2:15:50 PM
      - Did some digging. maybe this will help. - REB - 4/25/2007 2:30:44 PM
        
        re: Did some digging. maybe this will help. Thanks, REB. - Marcia - 4/26/2007 2:03:16 PM
        
        Speaking of a moon- could part of this planet's calculated mass be a moon? - REB - 4/26/2007 2:34:40 PM
        
        Not 4 Earth masses- 5 Earth masses. - REB - 4/26/2007 2:57:26 PM
        
        I would love to see a true binary-planet... Where two relatively equal planets are sharing the same center of gravity. - The Artist formerly known as Scott Evil - 4/26/2007 4:25:03 PM
        
        I wonder what it would have been like to have Venus as our moon. - REB - 4/26/2007 9:57:49 PM
        
        Very Good point! - The Artist formerly known as Scott Evil - 4/26/2007 2:50:57 PM
        
        Good detective work. You were correct! - ER - 4/25/2007 3:13:11 PM
      - re: Couple of questions: - REB - 4/25/2007 2:22:58 PM
  - re: Couple of questions: - ER - 4/25/2007 11:19:37 AM
    - re: The flares could themselves result in "seasons" on such a planet. - The Artist formerly known as Scott Evil - 4/25/2007 2:44:07 PM
      - Interesting... - nick hoffman - 4/25/2007 11:07:18 PM
        
        I've always thought of seasonality as being critical to drive evolution. - The Artist formerly known as Scott Evil - 4/26/2007 3:26:56 AM
        
        re: I've always thought of seasonality as being critical to drive evolution. - Joe P. - 4/26/2007 4:55:37 PM
        
        Interesting idea, I've started a new thread on it, I hope you don't mind. (n/t) - ER - 4/26/2007 2:36:15 PM
        
        Not at all. - The Artist formerly known as Scott Evil - 4/26/2007 2:53:31 PM
        
        Well Evolution Requires Either Genetic Drift Or Selective Pressure - M.A.E. - 4/26/2007 2:07:13 PM
        
        Getting wiped out can be good for evolution. - The Artist formerly known as Scott Evil - 4/26/2007 4:40:25 PM
      - Donâ€™t Red Dwarfs flair when they are young and calm down as they get older? - REB - 4/25/2007 2:48:57 PM
        
        Flares last minutes, maybe an hour or so (n/t) - phil - 4/25/2007 2:52:33 PM
        
        I mean a Red Dwarfâ€™s Flare frequency goes decreases as the star ages. - REB - 4/25/2007 2:55:23 PM
        
        rI'm specificly referring to red dwarf flare times (n/t) - phil - 4/25/2007 2:59:20 PM
  - Found a few answers - TB - 4/25/2007 6:13:19 AM
    - Also, what about moons, double planets - Sawyer - 4/25/2007 1:10:56 PM
      - Massive solar tides - ER - 4/25/2007 1:37:21 PM
        
        Tides - phil - 4/25/2007 2:58:39 PM
        
        Not sure about that... - TB - 4/25/2007 2:34:07 PM
        
        I think it would depend on the specific make-up of the planet and it's atmosphere (if any) - The Artist formerly known as Scott Evil - 4/25/2007 2:46:52 PM
        
        You're right about the tides, senior moment on my part. - ER - 4/25/2007 2:44:57 PM
        
        Don't be too hard on yourself - TB - 4/25/2007 4:25:37 PM
        
        re: You're right about the tides, senior moment on my part. - REB - 4/25/2007 2:57:21 PM
        
        re: Massive solar tides - REB - 4/25/2007 1:51:15 PM
        
        re: Massive solar tides - ER - 4/25/2007 3:09:29 PM
        
        Mercury - nick hoffman - 4/25/2007 10:50:38 PM
- Well, that's not fair... - TB - 4/25/2007 5:44:30 AM
- Data on this Star (from 2nd Gleise Catalog) - ER - 4/25/2007 12:03:02 AM
- Wow! - Peter Bruener - 4/24/2007 9:28:05 PM
  - re: Wow! - Raoul - 4/24/2007 9:41:52 PM
  - I got the size wrong. This planet is 50% larger than the Earth. - REB - 4/24/2007 9:38:30 PM
    - 2.2Gs at 5 Earth masses and 1.5 Earth radii - phil - 4/24/2007 9:50:09 PM
      - Thanks Phil - Peter Bruener - 4/25/2007 5:03:02 AM
        
        AP says 1.6G; I don't get it (n/t) - phil - 4/25/2007 4:01:24 PM
        
        Either way it would be a great place to train athletes (n/t) - FrankC - 4/26/2007 9:43:21 PM
        
        That seems high. Jupiter is something like 2.3-2.4 with over 300 times the mass of Earth. (n/t) - REB - 4/25/2007 4:17:52 PM
        
        Huge Difference In Density - M.A.E. - 4/25/2007 9:27:29 PM
        
        How do they know the radius? - ER - 4/25/2007 10:30:48 PM
        
        They Don't - M.A.E. - 4/26/2007 2:17:47 AM
        
        Radius - depends on density which depends on compositionj which depends on.... - n - 4/25/2007 11:24:02 PM
        
        A relevant paper online... - Adam - 4/27/2007 2:04:02 PM
        
        re: That seems high. Jupiter is something like 2.3-2.4 with over 300 times the mass of Earth. - ER - 4/25/2007 4:59:18 PM
- re: ESO discovery ! - Raoul - 4/24/2007 8:50:06 PM
  - D'oh! 50% larger than the Earth, not smaller. - REB - 4/24/2007 8:57:43 PM

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