the great attractor

[sculptor]

Ok
While considering gravity
the great attractor
came to mind
so
Is gravity the force leading us toward the great attractor
and
if so
then
does the center of our galaxy have a greater impact on gravity?
and
as we orbit around the galactic center---bobbing in and out of our galactic arm---
when we are 'in front'
of our galaxy heading toward the great attractor do the solar systems compress
thus increasing the level of gravity?
and, if so does this have an effect on our perceived gravity?

if the above is accurate
then the trailing arms would experience lower gravitational forces from our neighboring solar systems as they spread out as the
galaxy proceeded
ok
then
How would this be evident
and
then could we measure this?

 

[DaveC426913]

out of our galactic arm---
when we are 'in front'
of our galaxy heading toward the great attractor do the solar systems compress
thus increasing the level of gravity?
and, if so does this have an effect on our perceived gravity?

if the above is accurate
then the trailing arms would experience lower gravitational forces from our neighboring solar systems as they spread out as the
galaxy proceeded
ok
then
How would this be evident
and
then could we measure this?

You are talking about tides - the difference in gravity between the two extremes of an extended object.
The Milky Way is 100,000ly in diameter. The GA is 400,000,000ly away. That's a 4000:1 ratio.
Gravity falls off as the square of the distance, so the trailing edge of the MWG experiences a gravity that is 1-part-in-16-million less than that of the leading edge.

The short answer: yes, an ideally circular (and thus unreal) MWG would probably be fractionally distorted into an ellipse with an eccentricity of zero to several decimal places. Inasmuch as one can describe a diffuse object such as a galaxy as any kind of circle or ellipse at all.

 

[James R]

Ok
While considering gravity the great attractor came to mind so Is gravity the force leading us toward the great attractor

Yes.

does the center of our galaxy have a greater impact on gravity?

I can't understand what you're asking.

as we orbit around the galactic center---bobbing in and out of our galactic arm--- when we are 'in front' of our galaxy heading toward the great attractor do the solar systems compress thus increasing the level of gravity? and, if so does this have an effect on our perceived gravity?

DaveC has explained the tidal "compression", which would probably be negligible at this distance.

As for our perception of gravity, there would be no effect. Our entire galaxy is in "free fall" towards the great attractor. We are therefore no more aware of its gravity than we are aware of our Sun's gravity. That is, the size of the gravitational force doesn't matter, as far as feeling any effects from it.

 

[sculptor]

aware of our Sun's gravity. .

Solar tides?

 

[DaveC426913]

Solar tides?

All masses cause tidal forces on other objects.

The Earth's tides are Sun induced (as well as Moon-induced). When they are working against each other we get neap tides.

 

[James R]

Solar tides?

You were talking about about perception of gravity. Now you're talking about something different - the effect that the Sun's gravity has Earth's tides.

If I recall correctly, about 2/3 of the tidal effects are due to the Moon and about 1/3 due to the Sun. But I could be wrong.

You are currently accelerating towards the centre of the earth with an acceleration of 9.8 m/s^2. But you feel no gravitational force. All you feel is the ground pushing up on your feet, or your chair pushing up on your bottom, or whatever. You have no direct perception of gravity.

 

[sculptor]

You were talking about about perception of gravity.

ok
the tides are a perception of gravity.

If we can perceive that
with a little more effort
and tools
can we not perceive more?

 

[DaveC426913]

ok
can we not perceive more?

Yes. We perceive more and more every day. Are we not moving fast enough?

 

[James R]

ok
the tides are a perception of gravity.

Okay. I don't think it's worth quibbling about what we both mean by "perception" in this context.

We can agree that tides are caused by gravity. We can also agree that no human can directly feel the force of gravity.

Right?

 

[sculptor]

directly
ok
A few years ago, while visiting my son in the peace corps in Ecuador
I found myself on a mountain top hurtling toward the east in excess of 1000 miles per hour with no sensation of motion
no direct feeling of motion
but i knew that it was happening

our senses are a foundation
but limited

 

[DaveC426913]

Are we still talking about the Great Attractor?

Gravity from any sufficiently remote source is not directly felt as a force. Like in a freefall elevator, your feet and your head are falling at the same rate, so you feel no force between them.

Only if you were falling toward a very compact mass like a black hole (and thus the gravity source might only be millions of miles distant, rather than millions of light years), would you feel a difference in "pull" between your head and your feet. When you are falling into a black hole, you will feel stretched - 'spaghettified' is what they call it.

 

[geordief]

All masses cause tidal forces on other objects.

The Earth's tides are Sun induced (as well as Moon-induced). When they are working against each other we get neap tides.

I have been asking myself the last week or so if the spring tides that occur with a full moon are less strong than those which occur when there is no moon at all (just before the New Moon) as that is what I am seeing although I had always assumed them to be more or less the same.

Is that correct ?Is it the spring tides that happen with (or just after) the "empty" moon that tend to be the strongest ,with the highest high tides and the lowest low tides?

 

[James R]

I have been asking myself the last week or so if the spring tides that occur with a full moon are less strong than those which occur when there is no moon at all (just before the New Moon) as that is what I am seeing although I had always assumed them to be more or less the same.

I can't immediately think of any reason why those tides would be any different for a new moon, compared to a full moon. Perhaps something to do with the inclination of the Moon's orbit? (If so, the observed effect might vary depending on where you are on Earth.)

 

[DaveC426913]

I can't immediately think of any reason why those tides would be any different for a new moon, compared to a full moon. Perhaps something to do with the inclination of the Moon's orbit? (If so, the observed effect might vary depending on where you are on Earth.)

The only difference it makes is that - during a New Moon (which means we're looking at the side of the Moon opposite the Sun) - the tides of the Sun and the tides of the Moon are aligned.

 

[geordief]

The only difference it makes is that - during a New Moon (which means we're looking at the side of the Moon opposite the Sun) - the tides of the Sun and the tides of the Moon are aligned.

View attachment 5273

That would make sense to me then.

With the New Moon the two tidal effects work in the same direction whereas for the Full Moon they oppose each other.

In general it must be the Moon's tidal pull which is greater than the Sun's I would have thought.

 

[billvon]

We can also agree that no human can directly feel the force of gravity.

The otoliths in our ear respond to gravity. It's how we determine which way is up. You can feel that very distinctly when you go from 1G to 0G and back again.

 

[Contemplation]

Ok
While considering gravity
the great attractor
came to mind
so
Is gravity the force leading us toward the great attractor
and
if so
then
does the center of our galaxy have a greater impact on gravity?
and
as we orbit around the galactic center---bobbing in and out of our galactic arm---
when we are 'in front'
of our galaxy heading toward the great attractor do the solar systems compress
thus increasing the level of gravity?
and, if so does this have an effect on our perceived gravity?

if the above is accurate
then the trailing arms would experience lower gravitational forces from our neighboring solar systems as they spread out as the
galaxy proceeded
ok
then
How would this be evident
and
then could we measure this?

I believe the answer would undoubtedly have to be, no. It is just too far away and our relative position to it doesn’t change enough to create this effect.

It would be like the asteroid that broke apart before impacting Jupiter. It didn’t experience tidal forces until it came very close to impact.

Scientist where hardly able to detect gravitational waves from colliding black holes. I don’t believe they reported any type of interference from other tidal forces. If they did occur, it would have to be too minuscule for them to detect.

Our relative position to the great attractor in of itself would likely be too minuscule to detect. It wouldn’t give much hope for detecting a byproduct of that.

 

[DaveC426913]

The otoliths in our ear respond to gravity. It's how we determine which way is up. You can feel that very distinctly when you go from 1G to 0G and back again.

Well, they also respond to acceleration.

 

[billvon]

Well, they also respond to acceleration.

Absolutely. And from Einstein, we know that the two are identical in effect.

 

[James R]

The only difference it makes is that - during a New Moon (which means we're looking at the side of the Moon opposite the Sun) - the tides of the Sun and the tides of the Moon are aligned.

Yes, but does that make a difference?

Remember, there are tides on both sides of the Earth. There's a high tide directly below the moon, and another high tide on the opposite side of the Earth from the moon.