If the sun has a gravitational force, then why do light and heat come out from it?

 

Fig. The Sun, gravity, and light

Great question — this gets to the heart of how stars work!

The Sun’s gravitational force and its light/heat emission are two different but connected phenomena:

Gravity’s Role

• Gravity pulls all the Sun’s mass inward, trying to collapse it.
• This inward pull creates extremely high pressure and temperature in the Sun’s core.

Fusion and Energy Release

• At the core, hydrogen atoms are squeezed so tightly that they fuse into helium.
• This nuclear fusion releases enormous amounts of energy in the form of photons (light) and heat.
• The outward pressure from fusion balances the inward pull of gravity — this balance is what keeps the Sun stable.

Why Light and Heat Escape

• The energy produced in the core slowly travels outward through layers of plasma.
• Once it reaches the surface, it radiates into space as sunlight and heat.
• Gravity doesn’t “trap” light completely — only a black hole has enough gravity to prevent light from escaping. The Sun’s gravity is strong, but not strong enough to stop photons.

So, in short:

• Gravity makes fusion possible by compressing the Sun’s core.
• Fusion produces light and heat, which escape into space because the Sun isn’t dense enough to trap them.

What happens if the gravitational force of the sun becomes zero?

If the Sun’s gravitational force suddenly became zero, the consequences would be catastrophic and immediate:

Solar System Dynamics

• The Sun’s gravity is what keeps all planets, asteroids, and comets in orbit. Without it, Earth and the other planets would instantly stop orbiting and shoot off in straight lines into space, following Newton’s first law of motion.
• The solar system would disintegrate, becoming a cloud of wandering celestial bodies.

Impact on Earth

• Earth would lose its orbit and drift into deep space.
• Without the Sun’s gravitational pull, Earth would no longer receive stable sunlight — though the Sun itself would also collapse or disperse, so light and heat would vanish.
• Temperatures would plummet, oceans would freeze, and life would become unsustainable almost immediately.

The Sun Itself

• Gravity is what balances the outward pressure of nuclear fusion inside the Sun. If gravity vanished, the Sun would no longer be able to hold itself together.
• It would explode outward, dispersing its plasma into space, essentially ceasing to exist as a star.

Cosmic Consequences

• The Milky Way would remain intact (since it’s held together by the galaxy’s gravity), but our solar system would be gone.
• Earth and other planets would become rogue planets, drifting endlessly through interstellar space.

In short: the solar system would collapse instantly, Earth would be cast into the cold void, and the Sun would disintegrate. Gravity is the glue that makes the Sun a star and the solar system a system.