Bitcoin

ELI5 - What is Bitcoin and how does it work?

Bitcoin is the first decentralized cryptocurrency, created by the mysterious Satoshi Nakamoto in 2008. At its heart, Bitcoin is a list of transactions, showing who's sent and received the currency. Bitcoin can be moved between users' addresses, or public keys, by signing transactions with their corresponding private keys (like a password).

Rather than a central authority (like a bank) updating the list, Bitcoin introduced a new technology called blockchain, a cryptographic list distributed over a large network. Blockchain solved the main issue preventing the success of earlier digital currencies, namely allowing bad actors to spend their money more than once.

To do this, Bitcoin relies on users, known as miners, who loan computer CPU power to the network. Miners' computers make trillions of guesses to solve the trial-and-error math problem of organizing the latest transactions into a "block." Once a solution is found, however, the other computers in the network can easily verify it as correct. When this "consensus" is reached, the miner who solved the block receives a Bitcoin award, and their solution is permanently added to the blockchain.

By drollparadox7655 1 year ago

Blockchain

ELI5 - What is blockchain and is it safe? How?

Imagine you're playing a game with friends where you keep track of who owes what instead of using cash. You all write down debts and credits after each round. Once everyone agrees the list is correct, you move on. At the end of the game, you add up the list to see who owes or is owed money.

Blockchain is like this game's record-keeping leger, but digital and more secure. Instead of friend's names, it uses long digital addresses and private keys (like secret passwords). Introduced with Bitcoin, blockchain records every movement of a cryptocurrency to account for its current ownership.

Each new record on the leger, called a "block," needs everyone's agreement before joining the chain. While this was done by verbal agreement in our game, consensus is reached by something called "proof of work" in Bitcoin. Because Bitcoin's transactions require significant CPU (computer) power to organize, reorganizing the list is nearly impossible to fake. Bitcoin users called "miners" loan CPU power to the network to help organize the blockchain, keeping it secure, and receive Bitcoin compensation in return.

By drollparadox7655 1 year ago

Blockchain

ELI5 - What is blockchain and is it safe? How?

Blockchain, first introduced with Bitcoin, is a digital ledger shared across a network of computers. Each entry, called a block, records transactions, like sending or receiving digital money, with a unique, secure code. When a new transaction happens, it's added to a new block linked with a code to the previous one, forming a chain. This linking makes it nearly impossible to change past transactions without altering the entire chain, ensuring security.

Imagine it as a game where solving complex puzzles (mining) earns you points (cryptocurrency). When you spend or transfer points, that transaction gets recorded in the notebook. Everyone has a copy of this notebook, so cheating is hard because you'd need to fool everyone at once, which is practically impossible due to the puzzles' complexity.

This system allows for transparent, secure exchanges without needing a middleman, like a bank, making blockchain a revolutionary way to manage and verify transactions in a trustless environment.

By Alex 1 year ago

Speed of Light

ELI5 - Why can't anything move faster than the speed of light?

The speed of light is really about causality—cause and effect must happen in a logical order. Because space and time are linked together (spacetime), there's a natural limit to how quickly information or influence can travel from one place to another. If anything traveled faster than the speed of light, it would break this cause-effect relationship, making it possible for effects to happen before their causes, which violates basic logic. That’s why the speed of light acts as the universe’s fundamental speed limit.

By Alex 21 days ago

Planck Length

ELI5 - How is Planck length the shortest distance possible? Couldn’t you just split that length in half and have 1/2 Planck length?

The Planck length isn't the shortest distance possible, but rather represents the limit our current understanding of physics breaks down, being the scale at which the theories of both quantum mechanics and general relativity are simultaneously necessary, yet cannot be applied together without inconsistency. General relativity does not account for quantum effects, and quantum mechanics in its current capacity, does not provide an explanation for the effects of gravity.

In order to measure progressively smaller distances, photons with shorter wavelengths, and thus higher frequency/energy, are required. Quantum mechanics would suggest you could keep increasing a photon's energy to measure smaller and smaller scales, but general relativity predicts, due to mass-energy equivalence, as the photon's energy increases, so would gravitational effect until, eventually, a black hole forms.

This clash between QM and GR at the Planck length highlights the need for a unified theory of quantum gravity that can describe how gravity works at these tiny scales.

By Alex 7 months ago