<p>If a rock the size of Oumuamua were to crash into the sun — assume central collision — would it materially affect the sun’s behaviour? Would unaided humans (rather than sun-tastic special telescopes) notice a change in the sun’s brightness or colour or something?</p>

<p>What if the rock were the mass of Pluto? The Moon? The Earth? How big a rock can smite the sun and unaided humans not notice?</p>

<p>Edit: this is not about long-term effects of a merger. This is about the on-the-day or maybe in-the-month effects. How large would a rock need to be for its collision with the sun to have an effect? </p>

CC BY-SA 4.0
2019-09-03T22:36:54.137Z
See https://astronomy.stackexchange.com/questions/32654/what-would-happen-if-a-sun-like-star-were-to-consume-a-jupiter-like-planet
ProfRob
CC BY-SA 4.0
2019-09-04T03:57:46.100Z
Have you considered the relative size (mass) of the objects to the Sun ?  Earth is just 3 millionth the mass of the Sun.  That said, I'm pretty sure humans would notice if Earth was going to crash into the Sun. :-)
StephenG - Help Ukraine
CC BY-SA 4.0
2019-09-04T09:28:15.580Z
Good link, thank you. Jupiter is chunky. That article says “The scenario where a hot Jupiter just drops into the star from a distant radius would certainly have drastic short-term effects.“ But it is exactly these short-term affects that are the subject of this question. If Pluto were to fall into the sun, at a terminal velocity of a few hundred kilometres a second, it would substantially mix up some layers of the sun, as well as metallicising that local zone. Would the sun just shrug? Or would that greatly increase, locally, temporarily, brightness or flares or something?
jdaw1
CC BY-SA 4.0
2019-09-05T13:03:51.373Z
Not duplicate. That question about long term effects — mostly change in angular momentum — whereas my question about short-term.
jdaw1
CC BY-SA 4.0
2019-09-07T09:25:25.440Z
I think questions should be limited to what happens or might conceivably happen in the real world, rather than fantastic scenarios where Jupiter leaps out of its orbit and charges headlong into the sun.
Michael Walsby
CC BY-SA 4.0
2019-09-08T17:21:17.713Z
More than 10^11 suns in the Milky Way. Many have, or have had, planets. Formation of planets from interstellar gas likely to entail creation of many planetesimals, many of which ejected by near misses. A double-star system could even eject something as large as a gas giant. Hence there will be many ‘rocks’, sizes from Oumuamua to Earth+, wandering between the stars. Sometimes these will pass through a solar system. Sometimes, albeit not often, they will crash into a star. Hence conceivable. 

Were that to happen, would it be noticeable? Especially if the star resembled our sun?
jdaw1
<the-sun><asteroids><collision>
How big a rock can hit the sun and it not matter?
jdaw1
# How big a rock can hit the sun and it not matter?

(Asked by: username_0 on 2019-09-03)

If a rock the size of Oumuamua were to crash into the sun — assume central collision — would it materially affect the sun’s behaviour? Would unaided humans (rather than sun-tastic special telescopes) notice a change in the sun’s brightness or colour or something?

What if the rock were the mass of Pluto? The Moon? The Earth? How big a rock can smite the sun and unaided humans not notice?

Edit: this is not about long-term effects of a merger. This is about the on-the-day or maybe in-the-month effects. How large would a rock need to be for its collision with the sun to have an effect?

**Tags:** the-sun, asteroids, collision
> **Comments:**
> **username_1**: See https://astronomy.stackexchange.com/questions/32654/what-would-happen-if-a-sun-like-star-were-to-consume-a-jupiter-like-planet  
> **username_2**: Have you considered the relative size (mass) of the objects to the Sun ?  Earth is just 3 millionth the mass of the Sun.  That said, I'm pretty sure humans would notice if Earth was going to crash into the Sun. :-)  
> **username_0**: Good link, thank you. Jupiter is chunky. That article says “The scenario where a hot Jupiter just drops into the star from a distant radius would certainly have drastic short-term effects.“ But it is exactly these short-term affects that are the subject of this question. If Pluto were to fall into the sun, at a terminal velocity of a few hundred kilometres a second, it would substantially mix up some layers of the sun, as well as metallicising that local zone. Would the sun just shrug? Or would that greatly increase, locally, temporarily, brightness or flares or something?  
> **username_0**: Not duplicate. That question about long term effects — mostly change in angular momentum — whereas my question about short-term.  
> **username_3**: I think questions should be limited to what happens or might conceivably happen in the real world, rather than fantastic scenarios where Jupiter leaps out of its orbit and charges headlong into the sun.  
> **username_0**: More than 10^11 suns in the Milky Way. Many have, or have had, planets. Formation of planets from interstellar gas likely to entail creation of many planetesimals, many of which ejected by near misses. A double-star system could even eject something as large as a gas giant. Hence there will be many ‘rocks’, sizes from Oumuamua to Earth+, wandering between the stars. Sometimes these will pass through a solar system. Sometimes, albeit not often, they will crash into a star. Hence conceivable.   Were that to happen, would it be noticeable? Especially if the star resembled our sun?  

---

## 0 answers

