Here is a real world exoplanet that would make a great and terrible setting for gatecrashing:
http://io9.com/5834103/a-destroyed-star-becomes-a-planet-made-of-diamonds
https://secure.wikimedia.org/wikipedia/en/wiki/PSR_J1719-1438
https://www.sciencemag.org/content/early/2011/08/19/science.1208890.abst...
http://www.swinburne.edu.au/chancellery/mediacentre/resources/Diamond-pl...
It is a former stellar core orbiting the pulsar PSR J1719-1438 (period two hours and ten minutes, about 700,000 km away). And mostly made of diamondoid. With a diameter of just below five earths (55,000 km) and a mass of Jupiter, the surface gravity is 12.72 G.
If you are 1.8 meters tall it takes less than 0.17 seconds to trip over - and then you make a 13 times heavier impact than on Earth. Ouch. This is a place where a 1 meter fall is equivalent to falling 13 meters in 1 G.
The pulsar has a temperature of about 4500K, making it a flickering orange pinprick in the sky. It is sure to bathe the world in nice radiation and oscillating electromagnetic fields (it has a spin-down luminosity of 0.4 solar luminosities - it is shining very bright in radio at this close distance!). It is a millisecond pulsar with a period of 5.7 milliseconds - I wonder whether that might be in the range that induces neural activity in biomorphs or does weird entrainment of gamma waves? If so, it might have odd psychological effects too.
Not sure if it would be tidally locked; I doubt it. Definitely no moons (since the original star was stripped away, the moons/planets would have followed).
The surface environment likely includes an atmosphere of mostly carbon dioxide over a very flat landscape. A big question is how old the place is, since it determines the temperature. It could be fresh and glowing, or cooled down to a frosty state. Diamond is an excellent thermal conductor, so it would likely cool off relatively quickly. It is also an electrical insulator, so I don't think the pulsar will induce heating with its fields. However, deposits of more conductive compounds might cause local heating.
Anyone up for diamondoid based high gravity lifeforms, with lichen-like plants feeding on the EM fields using antennas?
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