Is zero gravity true?

No, zero gravity, as popularly understood, isn't true. According to current scientific understanding, gravity is always present, even in space. The feeling of weightlessness experienced by astronauts is due to freefall, not the absence of gravity.

Understanding Weightlessness and Gravity

The common misconception is that in space, there is no gravity. However, this is incorrect. Gravity is a fundamental force of nature, and it's always present.

• Weightlessness: This refers to the sensation of having no weight, which occurs when an object is in freefall.
• Gravity: The force that attracts objects with mass towards each other.

Why Astronauts Feel Weightless

Astronauts orbiting the Earth feel weightless because they are in a constant state of freefall. Both the spacecraft and the astronauts inside are falling towards Earth, but they are also moving forward at a high speed. This combination of falling and forward motion results in them continuously orbiting the planet.

The Earth's Gravity in Space

The Earth's gravity extends far beyond the planet's surface. In fact, the Earth's gravity is what keeps the Moon in its orbit. Astronauts are generally much closer to Earth than the Moon, meaning the Earth's gravitational pull on them is still significant. According to the reference, "there's no such thing as zero gravity... The earth's gravity keeps the moon in orbit. And astronauts are generally much closer to earth than the moon is, which means that the earth's pull on them has to be much stronger."

Examples of Gravity at Work

• The Moon's Orbit: The Earth's gravitational pull keeps the moon in a constant orbit around the Earth.
• Artificial Satellites: Satellites are kept in orbit by the Earth's gravity.
• Astronauts in Space: Although astronauts feel weightless, they are still subject to the Earth's gravity, which keeps them orbiting the planet.

Table Summarizing Gravity Concepts