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'Fingerprints' inside the Sun could reveal if it once swallowed a planet

133 points by blincoln 2mo ago

A_D_E_P_T 2mo ago
> Their results favour a scenario in which the young Sun engulfed a super-Earth around 5–10 times the mass of Earth Given the state of the early solar system, it would be surprising if the Sun didn't swallow a lot of metallic and carbonaceous rocks and pebbles. But it seems unclear to me how the researchers would distinguish between one super-Earth and >10^10 smaller rocks? Chemically I feel the two would be largely the same.
- cfiggers 2mo ago
  That's easy, they'll check whether there's one big fingerprint vs >10^10 little tiny fingerprints and conclude accordingly \j
  - amelius 2mo ago
    [flagged]
    - rotringlvr 2mo ago
      [dead]
    - snovv_crash 2mo ago
      You sound bitter about this.
- omnicognate 2mo ago
  > Researchers also found that such a world could survive its passage through the Sun's outer layers while losing very little mass, which suggests that planets may leave detectable fingerprints inside their host stars long after they have disappeared. So I guess the large size would have permitted it to smuggle stuff into the core that would have just vaporised in the corona if carried by many smaller objects?
  - monster_truck 2mo ago
    Sounds reasonable to me. But also what the fuck happens to the core of such a planet when that happens? We aren't actually sure what gave our core the spin it has, right? I'm not fully awake yet but I think it's plain where I'm going with this.
    - andrewflnr 2mo ago
      It's not plain to me where you're going. But the answer about the core of a planet engulfed by the sun is that it vaporizes eventually, just not right away.
    - frutiger 2mo ago
      > We aren't actually sure what gave our core the spin it has, right? We are, it’s from the conservation of angular momentum. The material that made our planet also had a non-zero angular momentum.
      - monster_truck 2mo ago
        No we aren't. That's a theory that barely fits the lower bound of what we estimate the spin of the core to be
- bell-cot 2mo ago
  This, but how do they rule out the extra stuff landing in the sun much earlier - when the solar system was still a pre-solar nebula, and which bits would end up where (sun vs. planets vs. whatever) was far from settled?
- hydrogen7800 2mo ago
  >But it seems unclear to me how the researchers would distinguish between one super-Earth and >10^10 smaller rocks? I have a similar feeling when life on earth is suggested to be "alien", arriving via debris in the solar system as the earth formed. Isn't everything in the solar system coalesced from the same debris?
  - jojobas 2mo ago
    The life-bearing debris would have to arrive quite some time after formation of Earth, as it was molten. Surviving atmospheric entry is hard, surviving after landing in lava is impossible.
    - gohomeloser 2mo ago
      [dead]
    - hydrogen7800 2mo ago
      I was going to expand on my comment about the difference between alien and non-alien being a difference only in time. It's all from the same stuff.
      - post-it 2mo ago
        It makes a difference to our understanding of the conditions under which life can form.
    - BurningFrog 2mo ago
      If life-bearing debris exists, it would surely be floating around the galaxy forever.
  - tracerbulletx 2mo ago
    That always felt like a deus ex machina answer to me too. We don't know exactly how abiogenesis happened on earth so some people just like to cut off the chain of causation with the idea of, "it was seeded"... but then how did abiogenesis happen elsewhere? I don't think that's a very popular theory among anyone who knows what they're talking about though.
- andrewflnr 2mo ago
  I don't fully follow (not being an astrophysicist), but it seems like the depth of the metallic material within the star matters a lot for their model. A planet can "bury" it (their word) a lot deeper than small rocks by physically sinking in before it gets destroyed. Sections 4.2 and 4.5 (among others I assume) in the actual paper linked above talk about this stuff.
N_Lens 2mo ago
That’s it Apollo! Spit it out, what’s in your mouth, spit it out now!
hnd9q09qk4 2mo ago
Did stellar abundance fits in grad school, getting the Teff systematics out took months.
run-good-code 2mo ago
When I saw the word 'Fingerprints', I thought it was a brilliant expression.
Martin_Silenus 2mo ago
I once ate a peanut too.
mturk 2mo ago
MESA, a piece of software referenced in this article, is a pretty incredible system. (Even referring to it as software underplays the extent of its community and impact.) Many people are involved in MESA and Bill Paxton was always quick to point out the many new folks that worked on it, but this article does a great job of celebrating his impact: https://www.kitp.ucsb.edu/news/an-accidental-astrophysicist https://www.kitp.ucsb.edu/news/an-accidental-astrophysicist It's amazing to me that he went from being the voice on the other end of the Mother Of All Demos to having such a major impact on stellar astrophysics during his "retirement." He passed away in 2025.
- vesinisa 2mo ago
  Thank you, that definitely was an interesting read. Sad to learn of Bill Paxton's passing. Clearly his legacy and impact however live on, like this research demonstrates. It seems he preferred the term "software instrument" to refer to MESA: > Bildsten and Paxton have taken to calling programs like MESA "software instruments,” according to the latter. “Just like you can’t do observational astrophysics without an instrument like a telescope," he said, "you can’t do computational astrophysics without an instrument such as MESA." It's amazing what impact one good piece of software, freely available to anyone anywhere to use, can have on a field. I think this quote illustrated the problem he was able to solve very well: > Ideally, you want to be able to run an experiment, but you can’t go grab a star, run an experiment for a billion years, and come back later to see how it turned out.
jcims 2mo ago
You have to get nearly halfway from the surface of the sun (photospere) to its core before the density of the sun’s material is equivalent to that of the earth.
regularfry 2mo ago
Has someone got a quick explainer for why adding a planet would result in less lithium? Is it just that a super-earth would be big enough and have so little lithium that it would measurably water down the other elements?
- accrual 2mo ago
  Not an astrophysicist, but since they mentioned the lithium is depleted, I wonder if that implies the collision of a planetary body with a sun would consume or react with the solar lithium.
- gus_massa 2mo ago
  Neither an astrophysics. I skimmed the paper. IIUC the collision with the planet mixed internal layers of the Sun and a lot of the Lithium went to the core and got fussed with Hydrogen. PS: The paper says that that actual A(Li)=1.1 instead of the expected A(Li)=3.3. I needed a lot of search to understand it until Gemini kindly liked this page. https://astronomy.stackexchange.com/questions/61814/what-do-lithium-abundance-numbers-mean-in-catalogs-like-hypatia https://astronomy.stackexchange.com/questions/61814/what-do-... A(Li)=1.1 means the Li/H ratio is 10^(-10.9) = 10^(-8.9)% A(Li)=3.3 means the Li/H ratio is 10^(-9.7) = 10^(-7.7)%
kleton 2mo ago
Nominative determinism- first author's name "Mutlu Yıldız" means "happy star"
- deleted 2mo ago
  [deleted]
Razengan 2mo ago
That sentence is kind of scary. Imagine being a civilization on a planet that knows it's going to be swallowed by their sun.. (during the lifetime of the living members)
- acjohnson55 2mo ago
  The book Seveneves is about civilization confronting impending doom from the moon exploding. I never finished the book because I felt it was depressingly realistic.
roshanabdullah1 2mo ago
and how exactly are we going to put our fingers into the sun?
huurtehoog 2mo ago
I find it endlessly fascinating that information cannot be destroyed and we keep finding more and more ways to read the universe at every scale!
spectraldrift 2mo ago
This might just be me, but I find metaphors like ''Fingerprints' inside the Sun' harder to read than the title of the original paper, which is probably what should be linked here per HN submission guidelines: > Planetary engulfment as a solution to solar-model discrepancies and its implications for planetary systems https://doi.org/10.1093/mnras/stag1527 https://doi.org/10.1093/mnras/stag1527 For the press release, something like The Real Sun and Its Simulations Disagree. A Planet That Fell In Early Might Explain It. might be easier to follow.
- birdsongs 2mo ago
  There's been a lot of changed titles recently, and it is quite annoying. I feel like that used to get corrected.
  - chrismcb 2mo ago
    This isn't a "changed"title. The title matches the linked "newspaper" article. But the op was saying that the research paper the article talks about has a better, easier to read, title.
odyssey7 2mo ago
Clearly wasn’t a “planet” — failed catastrophically at clearing its neighborhood. The Royal Astronomical Society should be ashamed for publishing something so un-scientific. /s
fainpul 2mo ago
About that artist's impression with the blue spiral: wouldn't any planet or other object do one of these things: - approach and hit directly, without spiraling - approach, make a close fly-by and fly off into deep space again - be in a steady, eliptical orbit My knowledge is basically that of a Kerbal.
- wongarsu 2mo ago
  There are obviously many things KSP's patched conics approximation can't account for, like lagrange points or how orbits often get twisted around over time, or how the small effects from all the other solar bodies add up to be significant over time. The simplest thing that comes to mind here is that KSP simulates a mature solar system, where space is mostly empty. This event happens in an early solar system, where there's lots of stuff everywhere. Running into stuff can steal some of the planet's momentum, causing it to fall deeper, causing it to run into more stuff But planetary migration can be a lot more complicated than that. [1] has an overview. You might also enjoy the Grand Tack hypothesis [2] which involves early Jupiter spiraling into the inner solar system until around the orbit of current-day Mars, before eventually reversing course and getting to its current orbit further out 1: https://en.wikipedia.org/wiki/Planetary_migration https://en.wikipedia.org/wiki/Planetary_migration 2: https://en.wikipedia.org/wiki/Grand_tack_hypothesis https://en.wikipedia.org/wiki/Grand_tack_hypothesis
coolThingsFirst 2mo ago
how hysterical would it be if the Sun decided to pull the earth into it. Discussions on X, Reddit and HN titled "Is this it" or "Heat death is medically comfortable". Crazy stuff.
GolfPopper 2mo ago
On a similar note, the Large low-shear-velocity provinces (LLSVPs) are structures in Earth's lower mantle that are hyothized to be remnants of Theia (the planetary-scale body that collied with, resulting in the formation of the Moon): https://www.nature.com/articles/s41586-023-06589-1 https://www.nature.com/articles/s41586-023-06589-1
imnotr0b0t 2mo ago
[dead]

133 points by blincoln 2mo ago

> Their results favour a scenario in which the young Sun engulfed a super-Earth around 5–10 times the mass of Earth Given the state of the early solar system, it would be surprising if the Sun didn't swallow a lot of metallic and carbonaceous rocks and pebbles. But it seems unclear to me how the researchers would distinguish between one super-Earth and >10^10 smaller rocks? Chemically I feel the two would be largely the same.

cfiggers 2mo ago
That's easy, they'll check whether there's one big fingerprint vs >10^10 little tiny fingerprints and conclude accordingly \j
- amelius 2mo ago
  [flagged]
  - rotringlvr 2mo ago
    [dead]
  - snovv_crash 2mo ago
    You sound bitter about this.
omnicognate 2mo ago
> Researchers also found that such a world could survive its passage through the Sun's outer layers while losing very little mass, which suggests that planets may leave detectable fingerprints inside their host stars long after they have disappeared. So I guess the large size would have permitted it to smuggle stuff into the core that would have just vaporised in the corona if carried by many smaller objects?
- monster_truck 2mo ago
  Sounds reasonable to me. But also what the fuck happens to the core of such a planet when that happens? We aren't actually sure what gave our core the spin it has, right? I'm not fully awake yet but I think it's plain where I'm going with this.
  - andrewflnr 2mo ago
    It's not plain to me where you're going. But the answer about the core of a planet engulfed by the sun is that it vaporizes eventually, just not right away.
  - frutiger 2mo ago
    > We aren't actually sure what gave our core the spin it has, right? We are, it’s from the conservation of angular momentum. The material that made our planet also had a non-zero angular momentum.
    - monster_truck 2mo ago
      No we aren't. That's a theory that barely fits the lower bound of what we estimate the spin of the core to be
bell-cot 2mo ago
This, but how do they rule out the extra stuff landing in the sun much earlier - when the solar system was still a pre-solar nebula, and which bits would end up where (sun vs. planets vs. whatever) was far from settled?
hydrogen7800 2mo ago
>But it seems unclear to me how the researchers would distinguish between one super-Earth and >10^10 smaller rocks? I have a similar feeling when life on earth is suggested to be "alien", arriving via debris in the solar system as the earth formed. Isn't everything in the solar system coalesced from the same debris?
- jojobas 2mo ago
  The life-bearing debris would have to arrive quite some time after formation of Earth, as it was molten. Surviving atmospheric entry is hard, surviving after landing in lava is impossible.
  - gohomeloser 2mo ago
    [dead]
  - hydrogen7800 2mo ago
    I was going to expand on my comment about the difference between alien and non-alien being a difference only in time. It's all from the same stuff.
    - post-it 2mo ago
      It makes a difference to our understanding of the conditions under which life can form.
  - BurningFrog 2mo ago
    If life-bearing debris exists, it would surely be floating around the galaxy forever.
- tracerbulletx 2mo ago
  That always felt like a deus ex machina answer to me too. We don't know exactly how abiogenesis happened on earth so some people just like to cut off the chain of causation with the idea of, "it was seeded"... but then how did abiogenesis happen elsewhere? I don't think that's a very popular theory among anyone who knows what they're talking about though.
andrewflnr 2mo ago
I don't fully follow (not being an astrophysicist), but it seems like the depth of the metallic material within the star matters a lot for their model. A planet can "bury" it (their word) a lot deeper than small rocks by physically sinking in before it gets destroyed. Sections 4.2 and 4.5 (among others I assume) in the actual paper linked above talk about this stuff.

N_Lens 2mo ago

That’s it Apollo! Spit it out, what’s in your mouth, spit it out now!

hnd9q09qk4 2mo ago

Did stellar abundance fits in grad school, getting the Teff systematics out took months.

run-good-code 2mo ago

When I saw the word 'Fingerprints', I thought it was a brilliant expression.

Martin_Silenus 2mo ago

I once ate a peanut too.

mturk 2mo ago

MESA, a piece of software referenced in this article, is a pretty incredible system. (Even referring to it as software underplays the extent of its community and impact.) Many people are involved in MESA and Bill Paxton was always quick to point out the many new folks that worked on it, but this article does a great job of celebrating his impact: https://www.kitp.ucsb.edu/news/an-accidental-astrophysicist https://www.kitp.ucsb.edu/news/an-accidental-astrophysicist It's amazing to me that he went from being the voice on the other end of the Mother Of All Demos to having such a major impact on stellar astrophysics during his "retirement." He passed away in 2025.

vesinisa 2mo ago
Thank you, that definitely was an interesting read. Sad to learn of Bill Paxton's passing. Clearly his legacy and impact however live on, like this research demonstrates. It seems he preferred the term "software instrument" to refer to MESA: > Bildsten and Paxton have taken to calling programs like MESA "software instruments,” according to the latter. “Just like you can’t do observational astrophysics without an instrument like a telescope," he said, "you can’t do computational astrophysics without an instrument such as MESA." It's amazing what impact one good piece of software, freely available to anyone anywhere to use, can have on a field. I think this quote illustrated the problem he was able to solve very well: > Ideally, you want to be able to run an experiment, but you can’t go grab a star, run an experiment for a billion years, and come back later to see how it turned out.

jcims 2mo ago

You have to get nearly halfway from the surface of the sun (photospere) to its core before the density of the sun’s material is equivalent to that of the earth.

regularfry 2mo ago

Has someone got a quick explainer for why adding a planet would result in less lithium? Is it just that a super-earth would be big enough and have so little lithium that it would measurably water down the other elements?

accrual 2mo ago
Not an astrophysicist, but since they mentioned the lithium is depleted, I wonder if that implies the collision of a planetary body with a sun would consume or react with the solar lithium.
gus_massa 2mo ago
Neither an astrophysics. I skimmed the paper. IIUC the collision with the planet mixed internal layers of the Sun and a lot of the Lithium went to the core and got fussed with Hydrogen. PS: The paper says that that actual A(Li)=1.1 instead of the expected A(Li)=3.3. I needed a lot of search to understand it until Gemini kindly liked this page. https://astronomy.stackexchange.com/questions/61814/what-do-lithium-abundance-numbers-mean-in-catalogs-like-hypatia https://astronomy.stackexchange.com/questions/61814/what-do-... A(Li)=1.1 means the Li/H ratio is 10^(-10.9) = 10^(-8.9)% A(Li)=3.3 means the Li/H ratio is 10^(-9.7) = 10^(-7.7)%

kleton 2mo ago

Nominative determinism- first author's name "Mutlu Yıldız" means "happy star"

deleted 2mo ago
[deleted]

Razengan 2mo ago

That sentence is kind of scary. Imagine being a civilization on a planet that knows it's going to be swallowed by their sun.. (during the lifetime of the living members)

acjohnson55 2mo ago
The book Seveneves is about civilization confronting impending doom from the moon exploding. I never finished the book because I felt it was depressingly realistic.

roshanabdullah1 2mo ago

and how exactly are we going to put our fingers into the sun?

huurtehoog 2mo ago

I find it endlessly fascinating that information cannot be destroyed and we keep finding more and more ways to read the universe at every scale!

spectraldrift 2mo ago

This might just be me, but I find metaphors like ''Fingerprints' inside the Sun' harder to read than the title of the original paper, which is probably what should be linked here per HN submission guidelines: > Planetary engulfment as a solution to solar-model discrepancies and its implications for planetary systems https://doi.org/10.1093/mnras/stag1527 https://doi.org/10.1093/mnras/stag1527 For the press release, something like The Real Sun and Its Simulations Disagree. A Planet That Fell In Early Might Explain It. might be easier to follow.

birdsongs 2mo ago
There's been a lot of changed titles recently, and it is quite annoying. I feel like that used to get corrected.
- chrismcb 2mo ago
  This isn't a "changed"title. The title matches the linked "newspaper" article. But the op was saying that the research paper the article talks about has a better, easier to read, title.

odyssey7 2mo ago

Clearly wasn’t a “planet” — failed catastrophically at clearing its neighborhood. The Royal Astronomical Society should be ashamed for publishing something so un-scientific. /s

fainpul 2mo ago

About that artist's impression with the blue spiral: wouldn't any planet or other object do one of these things: - approach and hit directly, without spiraling - approach, make a close fly-by and fly off into deep space again - be in a steady, eliptical orbit My knowledge is basically that of a Kerbal.

wongarsu 2mo ago
There are obviously many things KSP's patched conics approximation can't account for, like lagrange points or how orbits often get twisted around over time, or how the small effects from all the other solar bodies add up to be significant over time. The simplest thing that comes to mind here is that KSP simulates a mature solar system, where space is mostly empty. This event happens in an early solar system, where there's lots of stuff everywhere. Running into stuff can steal some of the planet's momentum, causing it to fall deeper, causing it to run into more stuff But planetary migration can be a lot more complicated than that. [1] has an overview. You might also enjoy the Grand Tack hypothesis [2] which involves early Jupiter spiraling into the inner solar system until around the orbit of current-day Mars, before eventually reversing course and getting to its current orbit further out 1: https://en.wikipedia.org/wiki/Planetary_migration https://en.wikipedia.org/wiki/Planetary_migration 2: https://en.wikipedia.org/wiki/Grand_tack_hypothesis https://en.wikipedia.org/wiki/Grand_tack_hypothesis

coolThingsFirst 2mo ago

how hysterical would it be if the Sun decided to pull the earth into it. Discussions on X, Reddit and HN titled "Is this it" or "Heat death is medically comfortable". Crazy stuff.

GolfPopper 2mo ago

On a similar note, the Large low-shear-velocity provinces (LLSVPs) are structures in Earth's lower mantle that are hyothized to be remnants of Theia (the planetary-scale body that collied with, resulting in the formation of the Moon): https://www.nature.com/articles/s41586-023-06589-1 https://www.nature.com/articles/s41586-023-06589-1

imnotr0b0t 2mo ago

[dead]