SCIENCE: JUPITER

Jupiter comprises 70 percent of all mass in our solar system. The sun's the only larger celestial body in our solar system.
Jupiter is 11 times larger than planet Earth. So, 11 Earths would fit around Jupiter's diameter.
A hollow Jupiter could hold 1400 planet Earths. [Source: Will Black Holes Devour the Universe? & 100 Other Questions & Answers About Astronomy by Melanie Melton]

If Jupiter were a bit larger it would become a star. How? Star formation starts with a cloud of hydrogen (nebulae). The hydrogen is confined to one part of the cloud. The cloud's mass increases gradually with the hydrogen concentration. That increase in mass increases the gravity, which traps more hydrogen. The crowding of hydrogen atoms generates heat. Eventually, the tremendous heat and pressure from the crowding causes nuclear fusion. When four hydrogen atoms are fused into one helium atom it produces a nuclear explosion. (This was the science first applied during the World War II atomic bombings of Hiroshima and Nagasaki.) Stars, such as the sun, have giant nuclear explosions occurring constantly. Just imagine millions of massive nuclear explosions occurring every second at once and you get the picture. Earth receives these bursts of energy from the sun as light and heat. Like the planets Saturn, Uranus and Neptune and the stars, Jupiter is comprised of mostly hydrogen gas--and no solid surface. Although it's huge it's still not large enough to start this process. [Source: Will Black Holes Devour the Universe? & 100 Other Questions & Answers About Astronomy by Melanie Melton and a forgotten website.]