After reading this article, you will understand what is the negative gravitational field, is gravitational field negative or not, and some detailed facts.
The region of antigravity, where the objects don’t feel the gravitational pull on them instead they will repel away from each other present in this field then it is a negative gravitational field.
What is Negative Gravitational Field?
The gravitational force is basically a force of attraction between the two objects and acts equal and opposite in magnitude and direction.
Due to some circumstantial forces, the objects will exert a force on the other objects in close vicinity to move them away from the gravitational field; this is known as the negative gravitational field.
The gravitational field region is a space within which the force is experienced on every object present in this field. Due to this, every object is bonded with each other with a tiny force that is not felt on the body but does exist. This gravitation force decreases as the distance from the object constituting its gravitational field increases, as the gravitational force is inversely proportional to the square of the distance among them.
m1 is mass of object 1
m2 is mass of object 2
‘r’ is a distance between the two objects
If the object is present in the negative gravitational field, then the objects will repel away from each other. Every object will exert a push force on the other object to push it away from its surrounding region.
The gravitational field is a region showing the force of attraction which is very small between the objects having a mass and is present in this field, and this gravitational force diminishes as the object moves away from another object or from the gravitational field.
How is Gravitational Field Negative?
The negative gravitational force is a very tiny repulsive force between the objects having masses due to the presence of dark matter.
The gravitational field is defined by the change in the gravitational potential of the field in every orbit around the massive mass which is equal to the negative gradient of the field strength; hence the gravitational field is negative.
The gravitational field strength is given as the force exerted by the object of mass ‘M’ on the object having mass ‘m’ at a distance ‘r’, given by the relation,
The gravitational force is formulated as, F=G mM/r2
Substituting this in the above equation, we get,
When the object is in the negative gravitational field, every object in this negative field will exert a force on every object to push it away from its own gravitational field as shown in the below figure.
If the object with mass ‘M’ has a greater gravitational potential field as compared to the object with mass ‘m’ present in the negative gravitational field, then the force applied by the mass ‘M’ will be greater than the object with mass ‘m’. If so is the case, then the object with mass ‘m’ will be displaced away from this massive object as it will repel from its negative gravitational field. The same is shown in the below figure. The object is displaced from its original position to a distance r+dr from the massive object having a mass ‘M’.
The work done by the mass ‘M’ to push the object away at a distance ‘dr’ is equal to the gravitational potential energy. Consider an object is repelled from the distance ‘r’ to ‘∞’, then the potential energy is,
The gravitational potential energy is positive. This signifies that this is a repulsive force between the two objects. We knew that the negative sign implies the force of attraction between the two bodies.
This gravitational potential energy is inversely proportional to the distance between the two objects, and hence we can say that the gravitational potential energy will decrease as the distance of separation of two objects increase further and further.
If we step into the next equipotential orbit, the variation in the gravitational potential energy of the object will be equal to the negative gravitational force.
dU/dr = -GMm/r2
The negative gravitational force decreases with subsequent orbits, and if these objects come in close vicinity of the positive gravitational field, then they will show the force of attraction towards these positive gravitational fields.
When is Gravitational Field Negative?
The gravitational force always shows a tiny force of attraction, but if the object is in the negative field then the objects will show a force of repulsion.
The gravitational force is negative if the object imposes a force on the other object to repel it away from its field instead of attracting and the potential energy of the field is positive.
The gravitational field becomes negative at an infinite distance where it becomes difficult to impose the force of attraction due to hindrance. The object will repel away from the gravitational field region of a certain massive mass if the potential energy of that object becomes equal to its kinetic energy. If the object gains enough kinetic energy to escape from the gravitational pull of that body, then the object will show repulsion from the massive object.
Read more on Gravitational Field.
Frequently Asked Questions
Does a dark energy is responsible for the negative gravitational field?
Dark energy is a theoretically postulated form of energy that is found in the entire universe and is considered a cause for the expansion of the universe.
The presence of dark energy leads to the opposition of the gravitational force due to it, thus causing an expansion and accelerating the object away from the gravitational field of the massive objects.
How is the gravitational force negative?
The gravitational force is not exerted on the object if it is present at an infinite distance from the gravitational field produced by the massive object.
The magnitude of the gravitational force is F = G m1m2/r2 but in vector form the force due to one mass is reacting in the direction opposite to the force due to another object, that is, F =-G m1m2(r2-r1)3/r2-r1 thus denoted as negative.
How can the gravitational force be repulsive?
If the object is at an infinite distance from the source object then the gravitational force will be a minimum due to that object.
At the same sequence if that object falls near the gravitational field region due to another massive object, then it will be attracted towards it and repel away from the gravitational field of another object present at an infinite position.
Does the explosion of supernovas signify negative gravitational force?
The gravitational force always points towards the center of any object having mass.
At the time of the explosion, the force due to gravity is very less compared to the centrifugal force acting outward, thus causing the explosion, and the gravitational field during this time is negative.
Does the work done by the negative gravitational field on the object is negative?
The work is done by the gravitational force present in the negative gravitational field to push the object away from its region to the low potential space.
The work done by the object will be the force imposed on the object to displace it at a distance ‘d’ which is Work done=-G m1m2/r2 d