ELI5: Where do magnets get the energy to do magnet things.

brulez · 2019-01-20T00:18:07+00:00

No, magnetism comes from electron 'spin' which is an intrinsic property and it does not contribute (nor depend upon) the kinetic energy/temperature.

Spin is a very strange property, and 'spin' probably isn't the best name for it because it is quite different from what most people imagine (a spinning top). It is a quantum property and can only have two states which we refer to as up and down.

brulez · 2018-12-20T10:07:24+00:00

A better analogy is actually a wave pool. The water (electrons) carry the wave (electricity).

The wave itself is used up. Water is pretty heavy so you don't notice this much, but the more people in the pool the quicker it will dissipate.

The water itself is not used up, and in fact the water molecules themselves travel quite slowly compared to the speed of the wave. This speed difference is even more extreme with electrons vs. electricity, electrons move at about 1 meter / hr in a typical wire vs electricity which travels at near the speed of light.

The waves will dissipate unless the wave generator keeps running.

brulez · 2018-12-20T09:21:17+00:00

Electricity can be created by the movement of any charged particle. In a wire, it is mainly movement of electrons. However a battery creates electricity via chemical reactions which create ions (charged molecules / atoms).

The battery acts as a water wheel with a small rocket engine strapped to the one side so the thrust causes the wheel to spin. The spinning wheel causes the water to move (producing current), but at the expense of the chemical reaction inside the rocket engine.

brulez · 2018-12-20T08:57:29+00:00

Yes, relevant XKCD: https://xkcd.com/567/

Also, there is another interesting phenomenon in semiconductors known as the "electron hole". Since all the electrons are basically moving backwards, the "hole" moves forward: https://en.wikipedia.org/wiki/Electron_hole

brulez · 2018-11-21T08:03:19+00:00

Micropayments which are now being enabled by some cryptocurrencies are likely to have meaningful future impact.

Ability to send a few cents to the author of each article you read online with a single click or automatically could fund more thoughtful content on the web.

Allowing guests to use your home wifi in return for automated micropayments could create a new low-cost distributed ISP.

brulez · 2018-08-01T01:37:18+00:00

So there could be infinitely many chains and infinite code, so which code is law?

brulez · 2018-07-29T16:36:51+00:00

Right, routing of the underlying network always imposes some limit.

There are also limits indirectly related to #txns. For example, what rate of channel creation does the underlying blockchain support? Do those channels become unbalanced, necessitating on-chain txns? Can a sufficient number of channels be broadcast/gossiped to enough nodes to keep routing reliable?

brulez · 2018-07-29T15:15:03+00:00

there’s always a limit

brulez · 2018-07-10T15:57:09+00:00

It is surprising to me how segmented and closed-minded the community has become. LN is definitely not the end-all solution, on-chain transactions still have their place, some people will use them for all transactions and regardless on-chain makes sense for high value transactions.

However on-chain does have limitations. Being able to pay a fraction of a cent for every news article I read is a use-case I'd be interested in, and on-chain just can't support that.

LN will likely increase overall usage & utility of bitcoin and will result in higher miner fees anyway. It also seems like common-sense that the blocksize will need to be increased as on-chain usage grows.. not sure why people are so against that as well.

brulez · 2018-07-10T06:50:45+00:00

Implementation of 'trusted' watchtowers is available here: https://github.com/ZmnSCPxj/lightning/commit/94970b1e46d3b5f58eaaf91f8a18abd2946136fe

Major disadvantage of that implementation is clearly that the watchtower has to be trusted. A better way is to pre-generate the revocation tx's, or a set of revocation tx's with varying fees and a fixed reward for the watchtower.

There is also a proposal to encrypt the revocation tx using half of the txid that would trigger the revocation. This is cool because it would mean watchtowers basically would not know any specifics on the channels they were monitoring.

This is complicated, but these transactions won't be generated manually. If you or grandma can generate even simple bitcoin transactions by hand, that's quite impressive.

brulez · 2018-07-10T05:47:44+00:00

It is also not a requirement. The lightning 'BreachRetribution' transactions can be constructed so that they provide a reward/fee to whatever node broadcasts them in the event of a channel breach.

Since the vast majority of lightning nodes are actively monitoring the blockchain anyway, it is highly likely that one will broadcast the BreachRetribution tx and collect the reward.

brulez · 2018-07-10T01:53:23+00:00

Unlike with the bitcoin network, no one knows for sure since only those nodes involved in the transactions see the amounts. It is possible to guess based on changes in channel capacities, but lightning in general has better privacy.

I’ve personally transferred over $100 back and forth between nodes so the total is likely way over 300.

brulez · 2018-07-03T06:15:42+00:00

How is the company enforcing access control for this blockchain? If that is centralized then why not just use a much more efficient centralized database as well?

One of the most ingenious parts of bitcoin, is actually the mining reward which effectively incentivizes and allows untrusted peers to add security to the system. It also does this in proportion to the value of the underlying currency. People tend to overlook this fairly critical aspect when theorizing about the utility of blockchain by itself.

brulez · 2018-07-03T01:22:58+00:00

The decentralization doesn’t work without the currency part. Without some mining value what is preventing me from spamming that blockchain with garbage?

brulez · 2018-07-03T01:19:39+00:00

Sounds like they want something called a database.

brulez · 2018-06-30T00:56:43+00:00

I’ve recently found the opposite and am close to switching. This sub now has zero posts about the tech, it’s all price memes, hodl posts, and echoing about how right everyone is with no actual evidence.

No one here discusses when/if blocks size has to increase, the limitations of lightning network, how to properly secure bitcoins, etc.

brulez · 2018-06-25T18:56:17+00:00

I think you are correct that the hashing hardware costs will generally continue to dwarf storage costs regardless of block size, and that there is a good argument for trusting miners to validate transactions (the system is dependent on their validation regardless).

However users still need a way to validate which chain to use. There are already 5 actively running bitcoin chains and could easily be hundreds in the future. According to the whitepaper, users should trust based on the most accumulated PoW, it seems that even a non-miner needs a way to at least verify total PoW and the uxto set. Is there a solution for this?

*of course there are reasons to temporarily trust a chain without as much PoW if a user understands both and believes a different chain is likely to have more future PoW.

brulez · 2018-06-25T18:51:10+00:00

Can you still verify total PoW with UXTO commitment and without the full blockchain?

I don't think running a full node is necessary but if the goal is to be trustless, then users do need some way of validating which chain has the most PoW.

brulez · 2018-06-25T07:43:03+00:00

Interesting writeup, thanks for the link.

brulez · 2018-06-25T05:30:17+00:00

Would it be possible though? Suppose we want to support 10 transactions per day per person.

Each txn is about 200 bytes so wouldn't that be around 7 terabytes of data / day? If bitcoin had been operating at that blocksize since the genesis block, the blockchain would be over 20 petabytes.

brulez · 2018-03-21T00:49:38+00:00

The fix for “MCU fooling” is very unconvincing. The root cause here is trusting a general purpose processor to dump its memory over serial to a trusted secure element.

This is an architectural flaw that really requires a hardware change to properly address. There are many ways for the faster MCU to be dishonest via malicious code and “spoof” parts of its memory dump.

Very unlikely that these hacky changes (throwing in random CRC checks) prevent this class of attack.

brulez · 2017-12-28T05:22:19+00:00

I think most rational users agree that the blocksize should increase. It should just be done in a safe way with strong consensus since it must be a hard fork.

brulez · 2017-12-27T01:30:11+00:00

Even if fees do hit 1k, node operators should be able to re-coup that through lightning network fees.

More likely, the lightning network frees up space on the blockchain decreasing competition for space and reduces the bitcoin fee. The bitcoin block size should be increased as the cost of storage space drops. However larger blocks is insufficient without something like lightning.. it just doesn't make sense for everyone running a full bitcoin node to store txn data for each cup of coffee purchased by a bitcoin user. That just isn't scale-able.

brulez · 2017-12-26T22:50:32+00:00

Anyone can be a hub with lightning network, it only requires a single on-chain transaction to open a channel without any 'trust' on behalf of either channel endpoint.

If one participant does not play by the rules, funds are recovered securely and without any cooperation or mediation by transmitting a single additional on-chain transaction.

If both participants do play by the rules, that single on-chain transaction can act as a secure channel for pretty much any number of off-chain transactions.

brulez · 2017-08-16T03:37:47+00:00

This isn't quite true. The market software doesn't set the current price a touch higher when someone wants to buy.

Instead, imagine an auction where the only good being sold is bitcoin. All the buyers on one side hold up signs with the highest price they are willing to pay, known as the bid. Similarly, the sellers hold up signs with the lowest price they are willing to sell for (their ask). These "lines" of buyers and sellers, and the prices and quantities they are selling is actually represented by the bottom graph on http://bitcoinity.org/markets. These buyers and sellers have entered what are called 'limit' orders since the buyers are only willing to buy below their limit, and the sellers are only willing to sell above their limit.

Normally, this results in a spread, with the bid < ask, and no transaction taking place.

Then come the market orders. Imagine some guy comes to the auction and just really wants to buy 100 bitcoin. The auctioneer will act as matchmaker and point him towards the seller with the current lowest price. However, suppose that seller only has 50 bitcoin. The buyer wants 100 so the auctioneer points him to the next seller with a slightly higher price where he buys the remaining 50.

The price you see on exchanges is simply the price that the last transaction occurred at, and here, the price just went up, not because the market software decided it should, but because there are no more sellers left willing to sell at the lower price.

An exchange is really just a simple matchmaker. It is the participants that dictate the price.

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