# Space and Astronomy for Kids/Space: Black Holes

Question
Hello, my friend and I got into a discussion about Black Holes today and I just need advice.
He posed the question would you rather have the power to change the weight of an object but not the size or size but not the weight. I said size but not weight so I could essentially create black holes.
He said "Take a pebble and increase it's weight and tell me you wouldn't create a black hole."
I said "no it would just be a very heavy pebble. Compress all the mass of the pebble, the escape velocity would be faster than the speed of light and that would create a black hole."
He then said
"I think you're confused lmao. You're agreeing with me right now lol. If you can increase the weight; you can achieve a black hole. But changing the size won't do shit without weight."

I said back "Changing the weight wouldn't do anything to the molecular structure of the pebble fam. It would just be a pebble that weighed a lot. If you took the pebble then made it super massive. Then made it collapse and pull all it's mass inward it would create a black hole. But by just changing the weight it wouldn't ever create a black hole. But to turn a pebble into a black hole it would have to be shrunk down unimaginably small, to turn the Earth into a black hole it would have to be shrunk down to the size of a mosquito."

He then said he would teach me about Gravity, Density and Mass.

So I was just wondering who is right. Lol

You are both wrong. Don't confuse weight and volume with mass and density. A stellar black hole is a star that collapsed to infinate mass and density yet has no size and has infinate gravity known as a singularity. The "size" of a black hole refers to its event horizon. The point of no escape. The event horizon is circled by the accreation disc.

Space and Astronomy for Kids

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#### Doug

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