Estamos hechos de estrellas

Gold and most elements were formed in space, not on Earth. Initially, only simple elements like hydrogen and helium existed. Through nucleosynthesis, stars act as factories, creating new elements via nuclear fusion. This process forms elements up to iron, which are exothermic. Elements heavier than iron require supernova nucleosynthesis, as they are endothermic. When stars die, they release energy, allowing the formation of these heavy elements, which are then dispersed into space. Almost all atoms, including those in our bodies, originated from stars and supernovae.

What process allows stars to create new elements from hydrogen and helium?

• Electrolysis

• Combustion

• Photosynthesis

• Nucleosynthesis

Why are nuclear fusion reactions that form elements lighter than iron considered exothermic?

• They require no energy input.

• They release more energy than they absorb.

• They absorb more energy than they release.

• They do not involve any energy change.

What is required for the formation of elements heavier than iron?

• Low thermal energy

• Endothermic reactions

• Exothermic reactions

• Normal star conditions

How are elements like gold and uranium formed in the universe?

• Via supernova nucleosynthesis

• Through normal star fusion

• During a star's birth

• By planetary collisions

What happens to a star when it stops generating energy by nuclear fusion?

• It remains stable indefinitely.

• It collapses and releases energy.

• It turns into a black hole immediately.

• It expands and cools down.