Re: Relevant - Plate Tectonics Might Only Occur on 0.003% of Planets. That Makes Earth Very Special Indeed.

On 7/5/2024 11:00 AM, Cryptoengineer wrote:
> On 7/4/2024 10:25 PM, Dimensional Traveler wrote:
>> On 7/4/2024 4:49 PM, a425couple wrote:
>>> On 7/4/24 12:33, Dimensional Traveler wrote:
>>>> On 7/4/2024 9:54 AM, a425couple wrote:
>>>>> Big DEAL !!
>>>>> So many times greats like Heinlein and Silverberg have written
>>>>> about us going to exoplanets, and it being like Earth.
>>>>> Sorry,,,, NO!
>>>>>
>>>>> from
>>>>> https://www.universetoday.com/167659/plate-tectonics-might-only-occur-on-0-003-of-planets-that-makes-earth-very-special-indeed/
>>>>>
>>>>> Plate tectonics: Image Credit: NASA/Goddard Space Flight Center 
>>>>> Scientific Visualization Studio
>>>>> POSTED ONJULY 2, 2024 BY SCOTT ALAN JOHNSTON
>>>>>
>>> -----------snip-------
>>>>>
>>>>> Go to the citation for the rest ----.
>>>>
>>>> I went to the citation but couldn't find if that 0.003% is of ALL 
>>>> exo-planets or just the Terrestrial/Super-Terrestrial types.
>>>>
>>>
>>> "the rest" of the citation, did not give a lot of specific information.
>>> Hopefully we will see a lot more on this research in the future.
>>>
>> I also think there's a flaw in their basic assumptions.  If you have a 
>> rocky planet with a liquid core/mantle, you are going to have plate 
>> tectonics.
> 
> Venus, Mars, and Mercury suggest otherwise.
> 
I believe Mars and Mercury's cores have solidified.  Venus has ... other 
issues but does have active vulcanism.  And considering how many it has 
may make up for the locked crustal plates.

> My impression is that the existance of a (relatively shallow)
> water ocean is critical. There's also a suggestion that a major
> meteor impact may have been involved in starting the process.
> 
Theia was a bit more than a meteor and yes, liquefying the entire planet 
a second time might have an effect.

-- 
I've done good in this world. Now I'm tired and just want to be a cranky 
dirty old man.