Are there any planets or moons denser than Earth?

  • Earth has the highest density out of all planets, planetoids and moons of our planetary system, and also has a higher density than the Sun. Do we know any exoplanets or moons denser than Earth?


    different but related: How small can a planet be and still have Earth-like gravity? as well as Is Earth's 1g solid surface gravity unusually high for exoplanets? and also Are there any known asteroids with average density similar to that of Earth's? This one may be hard to answer because there aren't likely to be very good ways to determine the masses of exoplanets directly. At least that's my guess.

    @uhoh Thank you for the links.

    you say earth has a higher density than that of the sun.... but given that the core is 150g/cm3 (vs earths 5g/cm3) when you say "density" do you mean "average density"?

    @UKMonkey I mean total density, not just the core or other layers. The Earth's core also has a higher density (12.9 g/cm3) than the entire Earth.

    @qqjkztd No, because there are no humans on other planets in this world unless one goes there from Earth. :-)

    Actually, Mercury has a much higher density (13.6 gm/cm3 as opposed to Earth's 5.5 gm/cm3). The planet may even be a remnant core of a much larger planet. Many similar exoplanets are out there, but I'd have to go through the NASA Exoplanet Archive https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=planets to find them. Check out the website, it's awesome with easy to use interactive capabilities.

    @JackR.Woods No, Mercury's density is 5.43 g/cm3 and Venus' is 5.24 g/cm3. While both are close to the Earth's they're not as high or higher. Your value is propably for Mercury's core only.

    @user30007 My mistake, I googled "density of Mercury". I would still say that Mercury has a very high density "for its size" indicating it being a possible "core remnant". Density does have a correlation with size given similar composition, so there must be many super-earths out there with a higher density.

  • sno

    sno Correct answer

    2 years ago

    From the Wikipedia page on Chthonian planet:



    Transit-timing variation measurements indicate for example that
    Kepler-52b, Kepler-52c and Kepler-57b have maximum-masses between 30
    and 100 times the mass of Earth (although the actual masses could be
    much lower); with radii about 2 Earth radii, they might have densities
    larger than that of an iron planet of the same size. These exoplanets
    are orbiting very close to their stars and could be the remnant cores
    of evaporated gas giants or brown dwarfs. If cores are massive enough
    they could remain compressed for billions of years despite losing the
    atmospheric mass.



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Content dated before 7/24/2021 11:53 AM