Primitive loaded glb file dimensions

[Nevnet99]

So I have loaded in a 3d world from a glb file

import { useGLTFLoader } from "drei";
import React, {Suspense, useEffect, useRef} from "react";
import { useLoader } from "react-three-fiber";
import {GLTFLoader} from 'three/examples/jsm/loaders/GLTFLoader'
import earth from "../assets/earth/out.glb";

function WorldGLTF({getWorldRef}) {
  const world = useRef(null);
  useEffect(() => {
    getWorldRef(world);
  }, [world.current])

  const gltf = useLoader(GLTFLoader, earth);
  console.log(gltf, "GLTF")
  return <primitive ref={world}  object={gltf.scene} ></primitive>
}

export default function World(props) {
    return (
      <Suspense fallback={null}>
        <WorldGLTF  {...props}  />
      </Suspense>
    )
  }

how would I get the dimensions from this I need to get the radius of the earth to plot satellites above it :)

any help is much appreciated :)