Bitcoin Blocks Date not coherent?

I was taking data from the BTC Blockchain with a custom script. I found something really weird.

Block nr. 24668 was created at 2009-10-09 23:02:57

Block nr. 24669 was created at 2009-10-10 00:15:48

Block nr. 24670 was created at 2009-10-09 23:15:43

Now tell me, how it’s possible that block 24670 is ‘younger’ than the 24669? I already checked and all the blockchain explorer websites show exactly this data.

Thank you for your attention,

Mattia

Understanding default bitcoin wallet in bitcoind

I am new to block-chain, so please bear with my questions. I need to understand the basics of a bitcoin-wallet. So I have setup a bitcoin full node using bitcoind in running in testnet mode. As I understand that by default a wallet is created. Now when I am trying to get the address of the wallet by this command bitcoin-cli -testnet getaccount "", I am geeting an empty list. So is there no default wallet as such, also how do I create a new wallet? As I understand that a bitcoin wallet is basically a pot which holds several child addresses?

Based on the coinmarket cap api, how do they calculate the bitcoin percent change

I am trying to figure out how coinmarketcap calculates the bitcoin percent change for other coins. For example on ethereum:

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I’m trying to figure out how they calculate that bottom BTC percent change 3.85%.

Their api (https://api.coinmarketcap.com/v1/ticker/?limit=100) spits out this data:

{     "id": "bitcoin",      "name": "Bitcoin",      "symbol": "BTC",      "rank": "1",      "price_usd": "8397.08",      "price_btc": "1.0",      "24h_volume_usd": "8190950000.0",      "market_cap_usd": "141531834530",      "available_supply": "16854887.0",      "total_supply": "16854887.0",      "max_supply": "21000000.0",      "percent_change_1h": "-0.51",      "percent_change_24h": "1.0",      "percent_change_7d": "-1.88",      "last_updated": "1518191066" },  {     "id": "ethereum",      "name": "Ethereum",      "symbol": "ETH",      "rank": "2",      "price_usd": "846.675",      "price_btc": "0.101377",      "24h_volume_usd": "3096660000.0",      "market_cap_usd": "82559453770.0",      "available_supply": "97510206.0",      "total_supply": "97510206.0",      "max_supply": null,      "percent_change_1h": "-0.2",      "percent_change_24h": "4.14",      "percent_change_7d": "-5.14",      "last_updated": "1518191052" } 

The first number is stated in this "percent_change_24h": "4.14" but they dont show how they came up with that second number ( 3.85% ).

Is there some formula I can create with the data they provide?

Thanks

Bitcoin RPC connection

I am trying to insert bitcoin transactions into MongoDB using python3. Below is my code :

import pymongo import sys import json import time from bitcoinrpc.authproxy import AuthServiceProxy, JSONRPCException  rpc_connection = AuthServiceProxy("http://xxx:xxx@ipaddress:port")  def getTransaction():     addresses = []     txa = []     commands = [ [ "getblockhash", height] for height in range(400000,550000) ]     #print(commands)      block_hashes = rpc_connection.batch_(commands)     blocks = rpc_connection.batch_([ [ "getblock", h ] for h in block_hashes ])     print(blocks)     for txpre in blocks:         #print(txpre)         for txs in txpre["tx"]:             txa.append(txs)     trans = conTransaction(txa)     return trans 

I am getting following error :

Traceback (most recent call last):   File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner     self.run()   File "/usr/lib/python3.6/threading.py", line 864, in run     self._target(*self._args, **self._kwargs)   File "Test06.py", line 252, in getBTCTransaction     block_hashes = rpc_connection.batch_(commands)   File "/home/administrator/.local/lib/python3.6/site-packages/bitcoinrpc/authproxy.py", line 165, in batch_     'Content-type': 'application/json'})   File "/usr/lib/python3.6/http/client.py", line 1239, in request     self._send_request(method, url, body, headers, encode_chunked)   File "/usr/lib/python3.6/http/client.py", line 1285, in _send_request     self.endheaders(body, encode_chunked=encode_chunked)   File "/usr/lib/python3.6/http/client.py", line 1234, in endheaders     self._send_output(message_body, encode_chunked=encode_chunked)   File "/usr/lib/python3.6/http/client.py", line 1065, in _send_output     self.send(chunk)   File "/usr/lib/python3.6/http/client.py", line 986, in send     self.sock.sendall(data) BrokenPipeError: [Errno 32] Broken pipe 

I checked bitcoind rpc connection,its connected.
block_hashes = rpc_connection.batch_(commands) this code line is giving error. Can somebody tell me what’s wrong? Working on a remote server.

Can bitcoin exist without miners?

In the past year only, the bitcoin mining difficulty has increased fivefold. If in the coming years the difficulty increases so much that mining is no longer profitable (i.e. consumes more power than money is earned), can the bitcoin network exist without miners? Can bitcoin supporters or governments have data centers that handle transactions only and do not spend computational resources on mining new bitcoins?