Bitcoin Mining - What Is It All About?

Every block, roughly every 10 minutes, 6.25 new Bitcoin are produced out of nowhere and paid to miners for providing security to the network. Originally, the mining reward, which is set by the software, was 50 Bitcoin per block. Current estimates are that this won't happen until 2140. If one person or group got a majority of the mining power, they could do bad things. This is called a 51% attack.