Newton’s lawsNewton's laws of motion are three physical laws that, together, laid the foundation for classical mechanics. They describe the relationship between
a body and the forces acting upon it, and its motion in response to those forces. The premise is, evidently, that the concept of “forces” is accepted as “true” without giving any origin to those “forces”.
More precisely, the first law defines the force qualitatively, the second law offers a quantitative measure of the force, and the third asserts that a single isolated force doesn't exist.
First law: In an
inertial reference frame, an object
either remains at rest or continues to move at a constant velocity, unless acted upon by a force.
Which doesn’t gives us any problem when an “object” is “at rest”. But when an object is in motion at a constant velocity, we cannot keep from asking ourselves, what put that object in motion
in the first place. We cannot, but we do keep ourselves from asking it.
Second law: In an
inertial reference frame, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma.
This formula gives
the added energy (force) given to the
factual energy producing the constant motion before acceleration. It doesn’t give any information on
the total energy manifested on the object which "factual force" is considered at zero, because we decide,
without any logical reasons, that all “forces” acting on the object equalizes themselves. The
reality is that “forces” equalizing themselves at a center point,
can produce extreme pressure on that point; which is never considered in this second law.
Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
So, one single isolated force
cannot exist. Which means that there can be no origin to expansion
before “contraction” (gravitation) exists. This is as logical as saying that a wall cannot push on you
before you push on it. Consequently, the “inertia” of an object
doesn’t exist until
a force is apply to that object. Meaning that an object
doesn’t have any weight before you start lifting it.
We have to take note that when Newton wrote his first and second law there was no references to an “inertial reference frame”, which was added when the laws where reformulated
to adapt to new discoveries.
Newton's law of universal gravitation states that a particle attracts every other particle in the universe using a “force” that is
directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres. It was shown separately that
large, spherically symmetrical masses attract and are attracted
as if all their mass were concentrated at their centers, which, evidently, is the
center of gravity.
Here we must observe that when we read “
large, spherically symmetrical masses” we are talking about a “
bundle of matter” and not a “
bundle of energy”. Even though “mass = energy”, the energy inside a “bundle of matter”
doesn’t always correspond to the total energy it possess, we then, must make a difference between “matter” and “mass”. And talking of “binding energy” doesn’t eliminate
the presence or the absence of that quantity of energy. Since it is
the total energy possessed by matter that alters the fabric of space-time,
at the center of gravity; we then should talk of “
mass energy” instead of simply “
mass”. Saying that “mass = energy” doesn’t give the complete information.
Now, to analyse the importance of those concepts, we must take in consideration that Newton laid the basic laws for classical mechanics
based on is observation of an object (apple) being attracted to the ground by another object (Earth).
All our actual physic is based on that concept.
To bring this concept at its
real value, we honestly must ask ourselves what would have been the basic laws of physic
if Newton had observed what Hubble saw in 1925; meaning that galaxies where “receding” from one another rather than being “attracted” by one another. It’s evident that all Newton’s laws would have been formulated in exact contradiction of what they were. Which gives us the importance we must attribute to these laws of Newton. In fact they are based on
nothing completely acceptable by observations.
We must accept, once and for all, the “fact” that objects
do not attract themselves and those same objects
do not “repel” themselves either.
Objects simply follow trajectories determined by the geometry of space-time.As for that geometry of space-time, it is either “flat” or “altered”. Nothing else is possible.
“Flat” geometry is rather simple to imagine; it’s a geometry of space-time that
doesn’t allow curved trajectories whatever the direction of the motion. Trajectories are always “straight” topologically and geodetically.
On the other hand, “altered” geometry is a bit more difficult to imagine since “space-time” has to be considered as “empty space” being “altered” by “mass energy”. Considering “mass energy” demands that “matter” itself
is withdrawn to second place in order to strictly consider the total energy involved in alteration of space-time. The result is that in an "altered" geometry of space-time, a trajectory is straight topologically and curved geodetically.
The next question becomes: What geometry of “empty space” could be “altered”, in order to influence geodetically a trajectory?
The only answer is: “the metric geometry” of space-time; because
there is nothing else than “metric” (distances) existing in empty space-time.
The next question would be: What could happens to the metric of space-time that could “alter” it?
Curiously, the only answer possible to this question is observed in the collapsing of a neutron star. The “fact” is that
the metric of the star collapses or “contracts”. Which brings us to the observation that is exactly
the “contrary motion” of expansion attributed to the universe (whole space-time).
Consequently we, definitively, observe
only two kinds of motions in the universe; the “expanding motion” and the “contracting motion”, with, all the intermediate intensity of motion, between those two extremes, that we find in the status of a galaxy.
It’s no use to defend or attack Newton’s laws; all we have to do is relate to the new basic concepts that were discovered since 300 years to readjust our physic.
What happens to an object going through a collapsing metric of space-time?
I’ll repost the drawing I previously presented and add one more information to it.

The importance of the added information on the right is that when we consider the basic metric of space-time being 10^-33 meter (Planck’s length), the difference between entrances of the object in succeeding metric is unnoticeable and the result is a smooth curved trajectory.