By David Swan • Updated August 30, 2022

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A star’s life cycle depends on its mass. Below is a hands‑on demonstration using five plastic globes and a string of Christmas bulbs, representing a typical star similar to our Sun.

Materials (order left‑to‑right):

• 6‑inch globe – Protostar (white bulb)
• 8‑inch globe – Newborn Star (orange bulb)
• 7‑inch globe – Stable Star (yellow bulb)
• 10‑inch globe – Red Giant (first red bulb)
• 6‑inch globe – Planetary Nebula (second red bulb)

Instructions:

1. Place the 6‑inch globe over the white bulb. Attach cotton wisps and a touch of silver glitter to mimic the surrounding gas cloud.
2. Position the 8‑inch globe on the orange bulb to represent a newly ignited star.
3. Set the 7‑inch globe on the yellow bulb to show the star in hydrostatic equilibrium.
4. Mount the 10‑inch globe on the first red bulb for the red‑giant phase.
5. Wrap crumpled tissue paper around the 6‑inch globe and place it over the second red bulb to illustrate the planetary nebula.
6. Finally, attach a 1‑inch white marble to the right side of the plywood to symbolize the resulting white dwarf.

Protostar

A protostar forms within a nebula, where gravity pulls hydrogen, helium, and dust together. The initial core heats as mass accumulates.

Newborn Star

When core temperatures reach about 10 million K, hydrogen fusion ignites, turning the protostar into a true star.

Stable Star (Main‑Sequence)

During this long phase, nuclear fusion balances gravitational collapse. Our Sun will stay here for roughly 10 billion years.

Red Giant

After hydrogen is exhausted, the core contracts and heats, causing the outer layers to expand dramatically—potentially engulfing Earth.

Planetary Nebula

The outer envelope is expelled, forming a glowing shell around the hot core.

White Dwarf

What remains is a dense, Earth‑sized core that cools over billions of years, emitting faint residual heat.

For more detailed information, see the NASA overview of stellar evolution.