Without stars in the universe there would be no elements other than hydrogen (H) and helium (He) which formed very soon after the universe exploded into EXISTENCE 13,800,000,000 years ago.

This is because all elements from atomic number 3, lithium (Li) to atomic number 92, uranium (U) are formed within stars or when stars end their lives and go supernovae. So, without stars there would be no iron (Fe), no carbon (C), no oxygen (O), no magnesium (Mg): then no animals, no rocks, no plants, no atmosphere, and no water. Basically planets could not exist and neither could you or I.

The mass in our Sun comes from mass sticking together as it floats through space. We can think of stars as big balls of mass that acquire energy by getting more mass, and lose energy by turning it into light.

We think of what would happen if there were no sun, or stars at all. Since our solar system was created in a cloud of dust that came from old exploding stars. If there were never stars to form this dust cloud, then our solar system would not have formed. There would just be a lot of nothing-ness.

Maybe Earth could have formed without stars, from some giant cloud of dust. Gravitational forces would cause dust to stick to Earth and with enough mass being “cooked” in Earth’s hot center, it would release light, acting like our sun!

The mass in stars, planets, and galaxies are all connected. A dust cloud, from old exploding stars, could stick to itself to form a planet, star, or asteroid. We call this kind of dust cloud a “nebula” and stars and solar systems form most easily here. If we look back to where our sun came from, we would find some nebula formed by exploded stars. But each one of these stars are formed by other nebulas, made by other exploded stars! We now see that many objects in space would not exist without the formation of stars. I hope this gives an answer to your question!

If the sun (a star) suddenly disappeared, many things would go wrong. Everything surrounding it that depends on its gravity would suddenly fly off their respective axes and into space. As for Earth, since it takes 8 minutes for light to get from the sun to us, our sky would go dark after 8 minutes! A few moments after that, the moon would also become invisible because it’s also lit up by the sun. Earth would eventually get very cold, freezing on the surface. The atmosphere would also freeze and fall to Earth’s surface, exposing it to radiation traveling through space. Life on Earth would eventually dwindle down to just a few microorganisms that were able to survive the harsh conditions. See, the sun is way more important than we give it credit it for!

If there is no sun in the universe, there is probably no light at all. I can hardly imagine a world or universe without light, as there is probably no living things at all. As a matter of fact, most of the planets without receiving enough light could be extremely cold, which is a disaster to living things. It could take billions of year or more for any living things to develop in such extreme environment.

The universe would be dark and cold. Everything would freeze. However galaxies would still be there, since the gravity that holds them together mainly comes from dark matter, not stars.