No, this isn’t a sci-fi term. Instead, it’s a term that refers to adjusting the difficulty of mining cryptocurrency in order to make things more fair.

Bitcoin mining is difficult and the difficulty is adjusted every 2,016 blocks. The block time of ten minutes means that adjusting the difficulty of Bitcoin can take nearly two weeks. Other crypto currencies saw this potential flaw and developed methods to adjust their difficulties dynamically and retain stability when big amounts of power enter or leave the mining pool. 

Multipools, such as GHash.io’s, have a significant amount of computing power and therefore can hugely increase the amount of hashing power in one particular crypto currency. This can dramatically decrease the block time and throw the rewards system off track.

The Kimoto Gravity Well was therefore invented to stop multipools and other powerful mining systems from affecting various crypto currencies. It does this by adjusting the difficulty every block instead of every 2,016 blocks. 

Another common difficulty readjustment algorithm is to combine multiple exponential and simple moving averages. This smooths readjustments and mitigates against exploits and other workarounds some people have tried against the Kimoto Gravity Well.

Thankfully Bitcoin itself doesn’t suffer this problem since the difficulty readjustment is rather limited due to the size of the Bitcoin network hash power. As an example, you’d need about $3million dollars to increase the rate by just 10%. Bitcoin is quite safe from difficulty readjustments that can benefit a mining pool and therefore doesn’t need the Kimoto gravity well -- though many other smaller cryptocurrencies do need it.