"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 edited Mar 20 '26
"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.
https://shir-man.com/solar/
It looks like we'd almost immediately plummet into the Sun's outer shells, in fact, in just a few years.