Why planets do not collapse under its own gravity unlike stars?

It is well known that stars do not collapse under its own gravity as long as there is nuclear fusion reaction which counteracts/balances gravity. But in contrast planets do not have any reaction that could balance its mass. So how and what is preventing planetary mass from collapsing by itself (I am not saying... show more It is well known that stars do not collapse under its own gravity as long as there is nuclear fusion reaction which counteracts/balances gravity. But in contrast planets do not have any reaction that could balance its mass. So how and what is preventing planetary mass from collapsing by itself (I am not saying planets should collapse and form a black hole which does not happen as long as the mass is less than 1.4 times solar mass, but still there must be collapse in the absence of any counter active force)?
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