What would happen if earth had only half of its gravitational force? By: Zaynub

The Moon

Prediction: If Earth's gravity is halved, then the moon would move farther away because Earth's gravity is what keeps the moon in orbit, so if the gravity were to be weaker it would not be able to keep the moon as close.

The moon and Earth
have strong gravitational
impact of eachother

Earth's gravity keeps
the moon in orbit.

The moon causes
tides on Earth

The moon's orbit is expanding
about 3.8cm per year

Stabilizes the Earth's axis

Tidal friction prevents Earth from rotating violently

Earth's Atmosphere

Gravity on mars is 3.7m/s^2,
and is unable to keep hold of
an atmosphere

Atmosphere had higher density in the past

Less than 1% as
dense as Earth's
atmosphere

Earth's Atmosphere

78% nitrogen,
21% oxygen,
almost 1% argon,
carbon dioxide, and
methane

Due to it's weak gravity, Earth does not have common gases such as hydrogen and helium, which the sun and the Jupiter have

Couldn't be held by the gravity so they evaporated quickly

The gravity of a planet pulls gases and aerosols of the atmosphere closer to the surface

Atmosphere of Mercury

Very thin because most of it has been released into space due to its very weak gravity

Life on Earth

Weight

Half gravity = half weight of everything

Plants

Gravitropism

Gravity sensing cells
in the roots of plants.

The response plants have
to gravity.

Roots grow towards gravity

Shoots of the
plant expand

reduction of gravity affects the
behaviour of fluids and gases needed
for plant growth and development

Human growth and strength

Astronauts in space
have been proven to
lose 2 percent of their
bone density every
week.

Conclusions:
- If gravity were halved, everything would weigh half of what it does now.
- In space, there is zero gravity, and if astronauts lose 2 percent of their bone density every month then with half of the gravity, people would lose 1 percent of their bone density every month, therefore, making us slowly weaker.
- Plants would grow differently; their roots would be shorter, and the gases and fluids needed would be different, therefore plants may not get all the nutrients they need to grow

Conclusions:
- If Earth's gravity was halved then Earth would not be able to retain all of it's atmosphere. The atmosphere would be thinner and it would be harder to breathe due to less oxygen being held in the atmosphere.
- Our atmosphere would slowly thin out, like mars, and would lack enough elements to sustain life and water.

Conclusions:
- Since the Earth's gravity keeps the moon in orbit, it is likely that the moon would move further away especially since it is already moving away at a rate of 3.8cm per year.
- If the moon moves far enough, it is also likely that Earth's axis would shift which would cause weather changes, and the Earth would start to spin faster, making our days shorter.

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