Bitcoin Forum

I've done some reading on mining and how it operates, but there are still some concepts that are beyond me; therefore, I need some clarifications.
 
My main concern is with mining, specifically with how long it takes to mine a block and why we use mining.
 
- What does the term "difficulty" in mining mean, and why is there difficulty in mining?

A block is mined averagely every ten minutes. It could be less than it or it could be more it depends on the amount of hash rate used. Just to keep this ten minutes in check we have to difficulty adjustment in every 2016 blocks approximately 2 weeks.


Difficulty is a bitcoin mechanism that keeps the mining of bitcoin block on average ten minutes. The reason because as more sophisticated mining tools like ASIC are produced there more hash rate that could get the bitcoin block mined in more faster way. With the difficulty adjustment every 14 day the network adjust to either reduce the difficulty of the next 2016 blocks if the previous takes averagely longer than ten minutes to mine a bitcoin block or increases the difficulty if the average time for mining a block in the previous block is less than ten minutes.

The difficulty is important to do that the block reward or bitcoin produce in every one block is halved in exactly every four years, the process as bitcoin halving. The current number of bitcoin produced by a block is 6.25 and the next halving is expected to happen in 2024

Read out more about difficulty here (https://learnmeabitcoin.com/beginners/difficulty)

To avoid overcrowding the forum with repetitive posts, attempt to carefully study before posting any questions to locate questions that are similar to yours and potential answers.

You can find the answers to your question
https://bitcointalk.org/index.php?topic=5447369.msg62026606#msg62026606

For better understanding you can read more on difficulty https://en.bitcoin.it/wiki/Difficulty



It takes about 10 minutes to mine a block

The answer on how long it takes to mine a block has already been answered. It's an average time of ten minutes kept at that range by a regular difficulty adjustment.
Mining has three distinct purposes:
-  it is used to confirm transactions,
- to ensure steady supply of Bitcoin,
- to keep the network secure through the hasrates required to mine, preventing any possibility of double spending.

How difficult it is to solve the computational puzzle and find the next block. This is the most basic explanation for it.
It exists to keep the time to confirm a block at an average of 10 minutes.

-Jay -

In a decentralized currency the transactions has to be stored in a ledger that is immutable (something that won't change). That ledger is called the blockchain (a chain of blocks). In this chain, each block is linked to its previous block and it is timestamped and produced by performing a certain type of "work" on it referred to as "mining". This work is performed using computing power and it is computationally expensive based on the network's target.
The cost of mining accompanied by the fact that the nodes follow the chain with the most work makes tampering with the ledger expensive hence provides immutability.

Because it is the only objective mechanism that lets us mint a currency, and verify transactions in a decentralized fashion. If you sit down, and think of another manner to have a ledger of transactions whose fate isn't in some central server, and whose money units are distributed fairly, you'll quickly notice it's impossible.

But, dive into the details if interested and/or still in doubt:

• https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch10.asciidoc#decentralized-consensus
• https://learnmeabitcoin.com/technical/mining

We use mining in order to do the following;

• Check and uphold the integrity of the blockchain
• Mining is also the only known means to validate transactions on the blockchain. This process takes alot of computational power and energy to be able to do work (proof of validation). So mining is need for a PoW system
• Miners also make it possible for all the bitcoin transaction to be included in the blockchain and remain immutable
• Finally we mine in order to have bitcoin rewards as incentives and also earn transaction fee

 In a layman's way, is to keep the bitcoin network secured. Mining becomes more or less difficult depending on the number of miners and their hashpower. If there's no difficulty in mining I think 51% attack would have happened since.

Usually, in Bitcoin syntax, validation is when you check that a transaction is valid, ergo it follows the consensus rules and is included in a block. Mining isn't the process of validating transactions. It's the process of including the transaction in block, or confirming it.

In other words, everyone can validate a transaction, just by running a full node. But not everyone can confirm a transaction, that requires mining.

No. If there was no difficulty, and the target remained the same as in 2009, we'd simply have new blocks mined every split second. (With much less security, due to increase in chain reorg frequency)

Good to know above facts as non miner or new comer in the mining development. The technology is undoubtedly fabulous and has got attention of millions of people. The fact that network is adaptive amuses me a lot. The network increases or reduces the difficulty with the time every 14 days based on how much mining has been done is something unique that I am learning today. I am really not sure why this limitation or factor was added to the network but that’s definitely to keep up the demand and supply of bitcoin ratio exponentially. Well correct me if I am wrong but that’s the logic I read on few sources.



But why this is so if 51% attack can never be achieved in practical approach? I am 51% mining power to single individual seems to be unreasonable. I read china was close to having this much power but that was not even individual but it was collective mining power across the china region.

I believe we are still far more safer with such unique and sophisticated algorithm.

To ensure that there will be new block mined once every 10 minutes on average. Not more, nor less than that.

Not sure what you mean. Difficulty adjustment simply makes bitcoin supply completely inelastic to demand fluctuations. It doesn't matter what the demand will be, the currency will inflate in the same prescheduled pace.

It takes +9mins to 'mine a block'
Just consider Bitcoin Mining as a way of working hard with your mining equipment to find or dig out new Gold/Bitcoin which is added to the gold/coin supply. Bitcoin mining is modelled after gold mining to give a feel of a hard money or hardwork based money that's not printed out of thin air like fiat currencies.


- Mining difficulty:  The more the gold-diggers/miners, the more difficult finding new gold becomes... The fewer the easier it becomes.
Part of the reason for the mining difficulty is to maintain the reward time intervals, to keep mining decentralized, balanced and competitive in relation to demand/profit.




*Edit: Note that in order to maintain the value of a currency it's important to make it hard to earn.  Or better still, people need to work hard or use energy to earn money. That's why Bitcoin PoW mining is really important and makes alot of sense.
~ Money = Workdone converted into "Potential Energy" to Power the Future

Yes, I am actually stating the same thing which you are defining it as inelastic. I just mentioned it in layman language and you defined it technically.  :D Now I understand why it was locked to those limits. Interestingly the calculations are so precise that it is still working properly till date. I gotten say Satoshi was one hell of a person to imagine this future and lock down every bit of coding precisely.

He knew that when first bitcoin will start to mine and he knew when it will end with the last bitcoin by the year 2140 etc etc. It is also interesting to imagine why the time was limited to 10 minutes only? Why not 1 hour or may 1 minutes? May be they had some other type of calculations in regards with the inelastic supply and timeline of the same. They could have brought it down and we would have seen all the bitcoins mined in may be 50 years or so. Must have been some thought or whether there is technical explanation to this as well?

New blocks are found ~ 10 minutes on average because it ensures the nodes, miners and the network are all on the same 'page', when miners confirm transactions and add them into a block, they propagate it to the whole of the network, if blocks are found for example 1 minute on average as you say, it would not give the miners enough time to know that the block they are competing for has already been mined and so they should start attempting to mine the next block, this will lead to chain splits and waste of computation power mining blocks that have already been mined.
It takes ~ 10 minutes on average, but there is no certain time, it can be slower or faster than 10 minutes exactly, but on average it will be ~ 10 minutes.