The relationship between Bitcoin and other digital currencies comes from several factors:

The relationship between digital currencies and Bitcoin? Why is Bitcoin going up when other currencies go up?

Liquidity and market size: Bitcoin is the most popular and liquid digital currency, and is often viewed as an indicator of the market as a whole. When Bitcoin moves significantly, the market follows because investors rely on it to determine the general trend.

2. Investor psychology: Many investors in digital currencies view Bitcoin as a leading indicator. If it starts to rise, they move to invest in other currencies (altcoins), and if it starts to fall, they exit the market or switch to Bitcoin or stablecoins.

3. Automated trading (Algorithms & Bots): Many traders use robots and software that rely on Bitcoin movements to make decisions about other currencies, leading to synchronized movements.

4. Historical correlation: Since the emergence of digital currencies, analysts have noticed that most alternative currencies move similarly to Bitcoin due to capital flows in the market.

5. Bitcoin Dominance: The more Bitcoin dominates the market (the percentage of its market value compared to other currencies), the more influence it has on other currencies, and vice versa when its dominance decreases.