# How can we say there is Zero G force in space what about SUN's G ?

• SBC
In summary: As for the G range, it extends to infinity because the force of gravity is a result of the mass of objects and their separation distance, which can theoretically be infinite.
SBC
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How can we say there is Zero G force in space what about Sun's G (I mean in our solar system or above Earth )?

Ok.. General theory of relativity says about bending of space and time. If I throw a rock into space where there is no G force even the small rock should fall towards the Sun(what about Sun's G force it should pull the Rock? ). Does rock stays at same position or it will fall to words the sun according to General theory of relativity (due to bending of space and time )??

ok... planets revolve around sun (Why planets Revolve around sun why not fall towards sun?)... But the rock doesn't revolve and it should fall towards the sun ... ?

We say that Suns G force is far Grater that Earth and G force of suns range should be high !
Than why space shuttle and others don't fall towards the Sun ?

Than why on Earth Zero G force ?

How can G range be infinity ?

General theory of relativity says "Force is consequence of Geometry"

so G range is limited. Why infinite range?

Welcome to PF!

Hi SBC! Welcome to PF!
SBC said:
»How can we say there is Zero G force in space what about Sun's G (I mean in our solar system or above Earth )?

We don't, we say there is microgravity in space … in a spaceship orbiting the Earth (with its engines off), a book floats because it too is in orbit, and its orbital speed is almost exactly the same as that of the spaceship (exactly exactly only if it is at the same distance from Earth as the centre of mass of the spaceship).

Using the spaceship as a frame of reference, there is almost zero gravity.

But in any other frame, there is plenty of gravity, as you say!
Ok.. General theory of relativity says about bending of space and time. If I throw a rock into space where there is no G force even the small rock should fall towards the Sun(what about Sun's G force it should pull the Rock? ). Does rock stays at same position or it will fall to words the sun according to General theory of relativity (due to bending of space and time )??

ok... planets revolve around sun (Why planets Revolve around sun why not fall towards sun?)... But the rock doesn't revolve and it should fall towards the sun ... ?

If you could place the rock stationary, then yes it would fall towards the Sun.

But if you threw it from Earth, or from a spaceship orbiting the Sun, it would start with all the orbital energy of the Earth or the spaceship, and it would continue to orbit the Sun near the Earth or the spaceship.

The planets do fall towards the Sun, but they are moving sideways so fast that manage to stay in orbit …

This is what Sir Isaac Newton realized when he saw the apple fall … if you throw an apple fast enough sideways, it will still fall, but the sideways movement keeps it in orbit.
We say that Suns G force is far Grater that Earth and G force of suns range should be high !
Than why space shuttle and others don't fall towards the Sun ?

Because the space shuttle orbits the Sun at the same speed as the Earth does.

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tiny-tim said:
Hi SBC! Welcome to PF!

We don't, we say there is microgravity in space … in a spaceship orbiting the Earth (with its engines off), a book floats because it too is in orbit, and its orbital speed is almost exactly the same as that of the spaceship (exactly exactly only if it is at the same distance from Earth as the centre of mass of the spaceship).

Using the spaceship as a frame of reference, there is almost zero gravity.

But in any other frame, there is plenty of gravity, as you say!

If you could place the rock stationary, then yes it would fall towards the Sun.

But if you threw it from Earth, or from a spaceship orbiting the Sun, it would start with all the orbital energy of the Earth or the spaceship, and it would continue to orbit the Sun near the Earth or the spaceship.

The planets do fall towards the Sun, but they are moving sideways so fast that manage to stay in orbit …

This is what Sir Isaac Newton realized when he saw the apple fall … if you throw an apple fast enough sideways, it will still fall, but the sideways movement keeps it in orbit.

Because the space shuttle orbits the Sun at the same speed as the Earth does.

I like your reply but if planets are not falling towards sun why not stone ?

How can G range be infinity ?

SBC said:
I like your reply but if planets are not falling towards sun why not stone ?

Because if the stone is launched from a planet, it will have the velocity of the planet in addition to its launch velocity.
How can G range be infinity ?

I don't understand why you're asking this …

why wouldn't it extend to infinity? why should it stop somewhere?

General theory of relativity says "Force is consequence of Geometry"
so G range is limited.

GTR says there is no force, only geometry of space-time, which extends everywhere.

SBC said:
I like your reply but if planets are not falling towards sun why not stone ?

How can G range be infinity ?
The planets *are* falling towards the Sun. However, their tangential velocities coupled with that inward acceleration makes them orbit the Sun rather than fall straight into it.

In your original post, you are confusing weight (gravitational force) with apparent weight (everything but gravitational force). We call space a zero-g environment because an astronaut's apparent weight is nearly zero on orbit. An astronaut's actual weight is about 90% that of that on the ground.

tiny-tim said:
Because if the stone is launched from a planet, it will have the velocity of the planet in addition to its launch velocity.I don't understand why you're asking this …

why wouldn't it extend to infinity? why should it stop somewhere?

If you are of my age hey BRO !
if you are older than me sir,

look at this .. I don't know why I feel that I found something wrong with sir.isaac Newton's Equation.

I think what you've found is a personal discomfort, nothing more.

ok... planets revolve around sun (Why planets Revolve around sun why not fall towards sun?)... But the rock doesn't revolve and it should fall towards the sun ... ?

------------->it (earth) will fall toward the sun but that's a long time from now

obing said:
------------->it (earth) will fall toward the sun but that's a long time from now

No … the Sun will come to meet us!

We're so lucky!

## 1. How can we say there is zero G force in space?

In space, there is a phenomenon known as microgravity, which is the almost undetectable gravitational force that exists in space. This is because objects in space are in a constant state of free fall, meaning they are accelerating towards each other due to gravity. This creates the illusion of zero G force, as objects and individuals in space feel weightless.

## 2. Is there truly no gravity in space?

While it may seem like there is no gravity in space, this is not entirely true. The force of gravity still exists in space, but it is much weaker compared to the gravity on Earth. This is due to the large distances between objects in space and the fact that gravity decreases with distance.

## 3. How does the sun's gravity affect objects in space?

The sun's gravity is the dominant force in our solar system, and it affects all objects in space, including planets, moons, and even spacecraft. The sun's gravity keeps planets in orbit and influences their movements, but it is not strong enough to create a noticeable G force on its own.

## 4. What is the difference between G force and microgravity?

G force is a measure of the force that an object experiences due to acceleration. In space, objects are in a state of free fall and are constantly accelerating towards each other, creating a microgravity environment. While G force can be felt on Earth, microgravity is almost imperceptible and creates the sensation of weightlessness.

## 5. Can humans survive in zero G force?

Humans can survive in a microgravity environment, as long as they have the necessary equipment and training. However, prolonged exposure to zero G force can have negative effects on the human body, such as muscle and bone loss, and changes in blood flow and vision. Therefore, astronauts on long-term missions in space must follow strict exercise and nutrition regimens to maintain their health.

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