What If Planet 9 Is a Primordial Black Hole?

Re:What If Planet 9 Is a Primordial Black Hole? by sliken on Thursday September 26, 2019 @02:12AM (#21078683)

Depends. Is the velocity of the black hole relative to the sun higher or lower than the escape velocity of the sun?

If higher than it's going to keep going, if lower, then yes eventually it's going to consume the sun.

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Re:What If Planet 9 Is a Primordial Black Hole? by 0-_-0 on Thursday September 26, 2019 @04:34AM (#21079235)

Wouldn't momentum transfer from the consumed mass slow it down?

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Re:What If Planet 9 Is a Primordial Black Hole? by sliken on Thursday September 26, 2019 @06:12AM (#21079636)

Some, but the sun isn't very dense. So sure if you were ever so slightly above escape velocity the consumed matter could slow you down.

A black hole the mass of the earth is 9mm. The weight of a cubic cm of sun is around 1.41 grams. The black hole isn't really going to notice.

The pass through the sun is around 1.39102e+11 cm * 1.41 grams per cm^3 = 139 million KG. So the earth weighs around 4.2* 10^16 more than what a black hole sized hole in the sun weighs.

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Re:What If Planet 9 Is a Primordial Black Hole? by 0-_-0 on Thursday September 26, 2019 @08:26AM (#21080261)

I thought its gravitational pull and the pressure around the black hole should cause it to absorb much more mass that that estimate.

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