What's the largest non-spherical astronomical object in the universe?

  • Some asteroids and comets are non-spherical. But is the nature of big things and gravity so that large things in the universe are always spherical? What is the biggest astronomical object in terms of volume out there that's not spherical?

    Note: Astronomical object is a defined term. See Astronomical object - Wikipedia.

    **Hint:** The more an object spins, the less of a true sphere it is.

    Also, collisions and explosions can create some interesting shapes. I guess it depends on what you consider to be a single object. Nebulae are not spherical.

    Perhaps a better question is what is the largest (almost) spherical object?

    You may be interested in the hydrostatic equilibrium, which is where an object over time will become spherical due to its own gravity. This equilibrium is dependent on multiple factors such as density, temperature and diameter.

    Hi @Hakonbogen. You may have the wrong idea: almost everything in the universe is **NON** spherical. *"But is the nature of big things and gravity so that large things in the universe are always spherical?"* - indeed, absolutely NOT. Gravity likes to make filaments, and pancakes. Most things in the universe are the shape of our galaxy, or, filament-like. Only when you get down to exremely small scales, like planets, do you get spheres. Cont...

    ... Even planets "want" to not be spheres: they like having rings and so on. The Earth-Moon (which is a unit) is a dumbbell, very unlike a sphere. Our solar system is a flat disk; and so on. Almost nothing is a sphere!

    Some supercluster, or more probably, the Bootes void.

  • The largest sub-galactic astronomical object (in volume) that we know of is the Carina Nebula, which is a non-spherical diffuse nebula. The Carina Nebula has a radius of about 100 parsecs.

    Carina Nebula

    Image credit: ESA

    If you consider astronomical objects of the galactic scale, then the galaxy IC 1101 is the largest astronomical object (in volume) that we know of. From Wikipedia:

    The galaxy has a diameter of approximately 6 million light years, which makes it currently (as of 2013) the largest known galaxy in terms of breadth. It is the central galaxy of a massive cluster containing a mass (mostly dark matter) of roughly 100 trillion stars. Being more than 50 times the size of the Milky Way and 2000 times as massive

    IC 1101 is on the left in the image below.

    IC 1101

    Here is an image from the Sloan Digital Sky Survey (SDSS) of IC 1101:

    SDSS IC 1101

    I'll leave it to you to decide if an elliptical galaxy counts as "spherical" or not.

    If you don't count elliptical galaxies, the largest spiral galaxy is NGC 262, pictured below. It has a diameter of 1.3 million light years.

    NGC 262

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

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