# Equivalent gravitational forces in other galaxies

• B
• jk22
In summary, the conversation discusses the possibility of the gravitational force in a galaxy being similar to that of a comet around a flat galaxy, where the strength of the pull varies in different directions. It also mentions the effect of multiple point-like masses on the overall gravitational force and the use of gravity to detect the density distribution of a planet.
jk22
Could it be imagined that due to a particular stars' distribution in a galaxy the gravitational force felt would be like $$f(\vec{e}_r)/r^{\alpha}$$ where $$\alpha\neq 2$$ but near 2 and f a non spherically symmetric function (like a comet around a flat galaxy) ?

What do you mean by "like a comet around a flat galaxy"?

The force has to be conservative, ##\displaystyle \int_0^\infty \frac{f(\vec e_r)}{r^\alpha} dr## has to be the same for all directions. If you have a weaker gravitational attraction in some direction at some point you need a stronger one in this direction at a different point.

jk22 said:
Could it be imagined that due to a particular stars' distribution in a galaxy the gravitational force felt would be like $$f(\vec{e}_r)/r^{\alpha}$$ where $$\alpha\neq 2$$ but near 2 and f a non spherically symmetric function (like a comet around a flat galaxy) ?

So basically, could the strength of the gravitational pull of an asymmetric galaxy e different in different directions at distances that are near to the galaxy relative to infinity?

If I understand you correctly, yes. It could. But, the formula you use is a point particle formula like the one in your post, and you'd need instead a formula that captures the sum of gravitational pulls from a whole host of different point-like masses. ∑ (f(i)/ri2 for i=1 . . . . billions of stars, which would create an effective force with r != 2 for an arbitrary point in space used to represent the galaxy as a whole.

jk22 said:
Could it be imagined that due to a particular stars' distribution in a galaxy the gravitational force felt would be like $$f(\vec{e}_r)/r^{\alpha}$$ where $$\alpha\neq 2$$ but near 2 and f a non spherically symmetric function (like a comet around a flat galaxy) ?

If r is measured from the center of the Earth's then gravity does vary. The Moon and Sun cause tides everyday.

Juno's gravity science probe flips your question. It is using differences in gravity to detect the density distribution of mass inside Jupiter.

## 1. What is the concept of equivalent gravitational forces in other galaxies?

Equivalent gravitational forces in other galaxies refer to the amount of gravitational pull that is present in other galaxies, which can be compared to the gravitational force experienced on Earth.

## 2. How do scientists measure equivalent gravitational forces in other galaxies?

Scientists use various methods, such as studying the motion of stars and galaxies, to determine the amount of gravitational force in other galaxies. They also use mathematical equations, such as Newton's law of universal gravitation, to calculate the gravitational forces between objects.

## 3. Are equivalent gravitational forces the same in all galaxies?

No, the equivalent gravitational forces can vary in different galaxies depending on the mass and distribution of matter within them. For example, galaxies with more mass will have a stronger gravitational force compared to smaller galaxies.

## 4. How do equivalent gravitational forces impact the formation of galaxies?

The equivalent gravitational forces play a crucial role in the formation of galaxies. The gravitational pull between matter causes it to clump together, which eventually leads to the formation of galaxies. Without sufficient gravitational force, galaxies would not be able to exist.

## 5. Can equivalent gravitational forces in other galaxies be stronger than on Earth?

Yes, equivalent gravitational forces in other galaxies can be much stronger than what we experience on Earth. For example, in a supermassive black hole at the center of a galaxy, the gravitational force can be millions of times stronger than on Earth.

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