Bitcoin Forum

I was looking at blocks on blockchain and saw this

https://photos-5.dropbox.com/t/0/AABCtjfsEVmcsNgmG88jiszjr_WJcZGpQkClD39KTETf5Q/12/25334765/png/2048x1536/3/1401728400/0/2/Captura%20de%20tela%202014-06-02%2016.14.10.png/k4edoa6Db6HRSMOnrydDCVWr8Jg6achDeI8QeLAgKnY

How can block 303839 be older than 303838 and 303837 ??

Thanks

Maybe a bug in the blockchain.info web software?

Assuming you are talking about blockchain.info, not the blockchain itself.  Blockchain.info is just one part of the network, it shows when it sees the block which is not instant it is mined.  It appears 303836-303840 were all generated within a very small window and so the order that they were generated and consequently built upon was not the same order that blockchain.info saw them.

yes, I thinked that was (the only..) loical reason for this, however as I had never seen this happening before I opened the thread.
Thanks

https://en.bitcoin.it/wiki/Block_timestamp

Not all computers are set to EXACTLY the same time.  Therefore, bitcoin allows some variation in the time stamps in the blocks.  The blocks were solved and added to the blockchain in exactly the order that they are numbered.  The chain of block hashes makes sure of that.

The time stamp is just an approximation of the date and time that the block was solved.  The protocol rules use the time stamp to prevent certain types of attacks against the blockchain.

It could very well be this http://money.cnn.com/2013/11/04/technology/bitcoin-flaw/ there has been a well known flaw in the bitcoin protocol which would have to be exploited with a lot of hash power close to 50% but even 35 or 40% could pull it off pretty easily through the getwork protocol. It is done by when a block is solved by pool they keep it secret and not broadcast to the network that a block has been found giving  whoever found the block a head start on everybody on the next block while everybody else is working on  a empty block that can't be found and has already been found. Ghash definitely has the hash power to pull it off that other I.P addy could just be a unpublicized address for ghash how  would we know?. I've noticed quite a few times right after ghash solves a block a unknown I.p quickly solves a block right after as well as conflicting times of back to back blocks solved by ghash? This is of course speculation but with the amount of blocks Ghash solves it is very well in the realm of possibilities........

before getting hysterical next time. try not just staring at blockchain.info. but also compare it to:
blockexplorer.com
blockr.io

if results show the same.. then decide if you really need to shout 'panic'

A bug?

No.

I see you are very emotional..
sorry "sweety"  :-* but there was no hysterism or panic on my sentence.. just a question

Lol, emotional one is you, you didn't even bother to search for the reason, panicked and took it to the forums.

ask a question <------> Panic!!!!

Ok I got it now. Sorry!

Well, you should search for the answer before asking. And if you're not panicking, you wouldn't be like "How is that possible???".

It is normal in Bitcoin for this to occur

Yes, The root cause of this is that without a central authority, it's impossible to know for sure what the current time is. Network time may differ from the actual time, since the bitcoin network attempts to correct for incorrect clock settings by taking the median of the time reported by all connected peers as the network time.

It says image unavailable, can anyone provide an imgur link or another direct link?

This things are one reason why confirmation times are so 'high' because under normal circumstances blocks should not be generated so close to each other or otherwise you can get conflicts over which block was first.

This is not a problem however, as a consensus is quickly reached and the blockchain will just build upon the longest chain.