user44191: Let's say I have simple computer (CPU- Intel i7 for example), and I start mining blocks in the bitcoin network. How much time in average does it take to create 1 block? (1 per week? 1 per month? 1 per 3 month? ....)
And if the answer is 1 per month or something like that, why not all the world participate in the mining process? it seems like an easy money to earn ...
And that's why I think that I missed something in my knowledge
Thanks in advance!

user5757: The answer is constantly changing, but this is something you can calculate yourself.

Look up the current Bitcoin difficulty value.  Right now it is 460,769,358,091.  Let's use scientific notation: 4.6e11.
The difficulty determines the average number of hashes needed to mine one block.  A minimum difficulty of 1 corresponds to 2^32 = 4.3e9 hashes, so we need an average of 4.6e11 * 4.3e9 = 2.0e21 hashes to mine a block.  (More precisely, each hash performed has a probability of 1 in 2.0e21 of successfully creating a block.)
Look up the approximate hash rate for the hardware you have in mind.  For CPUs and GPUs there is a table here; ASIC devices can be found here.  According to that table, a Core i7 2600 CPU can do 23.9 MHash per second, or 2.3e7 hashes per second.  Maybe you are starting to see the problem.
2.0e21 / 2.3e7 = 8.7e13.  That is the average number of seconds your computer will need to mine one block.  It is about 2.7 million years.

This should give you a sense as to why all Bitcoin mining is now done with specialized ASIC hardware, which is many orders of magnitude faster and more energy-efficient.

44191: <p>Let's say I have simple computer (CPU- Intel i7 for example), and I start mining blocks in the bitcoin network. How much time in average does it take to create 1 block? (1 per week? 1 per month? 1 per 3 month? ....)</p>

<p>And if the answer is 1 per month or something like that, why not all the world participate in the mining process? it seems like an easy money to earn ...
And that's why I think that I missed something in my knowledge</p>

<p>Thanks in advance!</p>
 5757: <p>The answer is constantly changing, but this is something you can calculate yourself.</p>

<ol>
<li><p>Look up the current <a href="https://bitcoinwisdom.com/bitcoin/difficulty" rel="noreferrer">Bitcoin difficulty value</a>.  Right now it is 460,769,358,091.  Let's use scientific notation: 4.6e11.</p></li>
<li><p>The difficulty determines the average number of hashes needed to mine one block.  A minimum difficulty of 1 corresponds to 2^32 = 4.3e9 hashes, so we need an average of 4.6e11 * 4.3e9 = 2.0e21 hashes to mine a block.  (More precisely, each hash performed has a probability of 1 in 2.0e21 of successfully creating a block.)</p></li>
<li><p>Look up the approximate hash rate for the hardware you have in mind.  For CPUs and GPUs there is a table <a href="https://en.bitcoin.it/wiki/Non-specialized_hardware_comparison" rel="noreferrer">here</a>; ASIC devices can be found <a href="https://en.bitcoin.it/wiki/Mining_hardware_comparison" rel="noreferrer">here</a>.  According to that table, a Core i7 2600 CPU can do 23.9 MHash per second, or 2.3e7 hashes per second.  Maybe you are starting to see the problem.</p></li>
<li><p>2.0e21 / 2.3e7 = 8.7e13.  That is the average number of seconds your computer will need to mine one block.  It is about 2.7 million years.</p></li>
</ol>

<p>This should give you a sense as to why all Bitcoin mining is now done with specialized ASIC hardware, which is many orders of magnitude faster and more energy-efficient.</p>
