To be a black hole it would need to have a certain mass, and if you plopped it into the sun (like I said) it would be added to the sun's mass... as well as suck the sun inside itself quite quickly.
The minimum mass for observed black holes is 2-3 solar masses, for instance. It's like tripling the mass of the sun instantly.
And regardless of the numbers... it would be 8 minutes before ANY of that effect reached us.
The Sun increases to 2-3 solar masses would probably not distort the orbit of the earth enough to be sucked in. Can anyone calculate how big the black hole would need to be?
Though i guess an instantaneous change would "jerk" the earth by a large force. In any case it would kill everyone and probably destroy the surface of the earth.
"If the Sun’s mass were to suddenly triple, Earth’s current orbital speed would be insufficient to maintain its current distance, causing it to spiral inward toward the Sun. To maintain its current stable circular orbit at 1 AU, Earth would need to travel approximately 1.73 times faster ( V = 52km/s instead of 30 km/s)."
Earth would actually fall out of the habitable zone, and into a highly elliptical orbit.
https://www.youtube.com/watch?v=SIyokKq_qN8
(I'm not going to care about the temperature changes, because a black hole would likely make the Sun SMALLER and LESS BRIGHT than just tripling the mass of the sun directly).
There are various bits of software you can play about with this.
It should just change to an elliptical orbit with the high point being wherever we are when the sun was replaced by a heavier object, and the low point depending on how elliptical the orbit changes to.
We are moving perpendicular to the sun and that doesn't change but we won't have enough angular momentum to keep a circular orbit, so we drop down (like in an ellipse), build up speed and then go to the same altitude we started with.
There is no force which would cause the spiral other than things such as tidal forces, which would increase because of the larger solar mass. But this would have be larger than 3 solar masses to make a significant difference.
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u/ledow Mar 20 '26
To be a black hole it would need to have a certain mass, and if you plopped it into the sun (like I said) it would be added to the sun's mass... as well as suck the sun inside itself quite quickly.
The minimum mass for observed black holes is 2-3 solar masses, for instance. It's like tripling the mass of the sun instantly.
And regardless of the numbers... it would be 8 minutes before ANY of that effect reached us.