What is S&P500? What is the difference with NY Dow?

$S&P 500 Index (.SPX.US)$ S&P500, formally known as the "Standard & Poor's 500 Stock Index", is published by S&P Dow Jones Indices LLC. It aims to cover major companies in the main industries of the United States. It selects approximately 500 stocks listed on the New York Stock Exchange and NASDAQ based on market size, liquidity, industry, and other factors. The index is calculated as a weighted average by market capitalization. As of April 2022, it covers about 87% of the total market capitalization of US stocks.
On the other hand, NY Dow (officially known as Dow Jones Industrial Average) is also published by S&P Dow Jones Indices LLC. It is characterized by having a very small number of 30 constituent stocks. Unlike S&P500, it calculates the index by averaging the prices of the stocks rather than by market capitalization. As of April 2022, it covers about 25% of the total market capitalization of US stocks. $Vanguard Total Stock Market ETF (VTI.US)$ $iShares Core S&P 500 ETF (IVV.US)$