Why do dropped objects fall?
Earth's gravity pulls objects toward Earth. Gravity is an attraction between objects with mass.
Everyday example
A dropped ball moves toward the ground.
Source: NASA Space Place: Gravity. Checked 7 October 2026.
Space
15 source-checked questions. A library, not live AI.
Do small objects have gravity?
Yes. Anything with mass has gravity, but the pull from small everyday objects is very weak.
Everyday example
You pull gravitationally on Earth as Earth pulls on you.
Source: NASA Space Place: Gravity. Checked 7 October 2026.
Does gravity change with distance?
Yes. Gravitational attraction becomes weaker as objects move farther apart.
Everyday example
An object farther from Earth experiences a weaker pull from Earth than the same object closer to it.
Source: NASA Space Place: Gravity. Checked 7 October 2026.
What keeps planets in orbit?
Gravity pulls planets toward the Sun while they move along their orbital paths.
Everyday example
Earth travels around the Sun under its gravitational influence.
Source: NASA Space Place: Gravity. Checked 7 October 2026.
Why does the Moon shine?
The Moon reflects sunlight. It does not produce its own visible light like the Sun does.
Everyday example
A bright full Moon is reflecting sunlight toward us.
Source: NASA Space Place: Moon. Checked 7 October 2026.
Why does the Moon seem to change shape?
As the Moon orbits Earth, we see different portions of its sunlit half. These appearances are called phases.
Everyday example
A crescent and a full Moon show different amounts of the lit side.
Source: NASA Space Place: Moon phases. Checked 7 October 2026.
Does the far side of the Moon stay dark?
No. The far side receives sunlight too. Far side means the side that normally faces away from Earth.
Everyday example
Both sides experience sunlight as the Moon moves around Earth.
Source: NASA Space Place: Moon. Checked 7 October 2026.
Why do we usually see the same side of the Moon?
The Moon rotates once in about the same time it takes to orbit Earth. This keeps roughly the same side facing us.
Everyday example
Rotation and orbital motion are matched, rather than the Moon not rotating.
Source: NASA Space Place: Moon. Checked 7 October 2026.
Why can astronauts jump higher on the Moon?
The Moon's surface gravity is about one-sixth of Earth's. A person's weight is lower there.
Everyday example
With a similar push, a jumper can rise farther under weaker gravity.
Source: NASA Space Place: Moon. Checked 7 October 2026.
What causes the seasons?
Earth's tilted axis changes how directly sunlight reaches each hemisphere and how long daylight lasts through the year.
Everyday example
When a hemisphere is tilted toward the Sun, it receives more direct sunlight.
Source: NASA Space Place: Seasons. Checked 7 October 2026.
Are summer and winter opposite across hemispheres?
Yes. When the Northern Hemisphere is tilted toward the Sun, the Southern Hemisphere is tilted away, and vice versa.
Everyday example
June is summer in much of the north and winter in much of the south.
Source: NASA Space Place: Seasons. Checked 7 October 2026.
Does being nearer the Sun explain summer?
Not the main seasonal pattern. Earth's tilt is the main cause; distance changes alone do not explain the opposite seasons in the two hemispheres.
Everyday example
The two hemispheres share the same distance from the Sun but can have opposite seasons.
Source: NASA Space Place: Seasons. Checked 7 October 2026.
Why do we have day and night?
Earth rotates. A place has daylight when it faces the Sun and night when it faces away.
Everyday example
As Earth turns, your location moves into and out of sunlight.
Source: NASA Space Place: Seasons. Checked 7 October 2026.
How does the Moon help create tides?
The Moon's gravitational pull affects Earth's oceans and contributes to the tides.
Everyday example
Water levels along a coast rise and fall in tidal cycles.
Source: NASA Space Place: Gravity. Checked 7 October 2026.
What is a black hole?
A black hole is a region where gravity is so strong that even light cannot escape from within its boundary.
Everyday example
It is not simply a dark cloud blocking a view.
Source: NASA Space Place: Gravity. Checked 7 October 2026.