What is gravity?
The discovery and concept of gravity have grounded and established so many different concepts of physics over the years.
Since the discovery of gravity in 1687 by one of the pioneers in the subject of physics, Issac Newton, this physical concept has opened multiple avenues of study, research, and more.
Though others had thought about it before him, Newton was the first to create a theory that applied to all objects, large and small, using mathematics that was ahead of its time.
In itself, the idea of gravity seems like a very simple concept.
It is the force that attracts a body towards the center of the earth, or towards any other physical body having mass. It is an invisible force.
Earth's gravity is what keeps you on the ground and what makes things fall.
Apart from Earth, other celestial bodies also have gravity.
This gravity pulls things to the center.
The force of gravity keeps all of the planets in orbit around the sun. It can be also defined as the universal force of attraction acting between all matter.
To date, it is the weakest known force in nature.
Thus it plays no role in determining the internal properties of everyday matter.
On the flip side, gravity has a long reach along with universal action.
Through these, it controls the trajectories of bodies in the solar system and elsewhere in the universe and the structures and evolution of stars, galaxies, and the whole cosmos.
It is important to remember that everybody that has some mass also has gravity.
It has been observed that objects with a greater amount of mass have more gravity.
The same goes for the opposite, as bodies with lower masses have lower gravity.
The other important thing to remember about gravity is that it varies according to proximity.
Objects that are closer to each other have a stronger gravitational pull than those that are distanced from each other.
Gravity is measured by the acceleration that it gives to freely falling objects. In the context of Earth’s surface.
The acceleration of gravity is about 9.8metres(32 feet) per second squared. In simpler terms, for every second as the object is in free fall, its speed increases about 9.8 meters per second.
It is important to note that gravity is not constant everywhere in this universe.
As gravity is measured in proportion to the mass of an object, it varies from one to another.
At the surface of the Moon, the acceleration of a freely falling body is about 1.6 meters per second squared.
All of Earth’s gravity comes from its mass.
All its mass makes a co, combined gravitational pull on the mass of our body.
That's what gives you weight. All bodies on earth have a certain weight.
This is crucial to the concept of gravity as our weight is technically the downward force of gravity, proportional to their mass, which Earth’s mass exerts on them.
If we were on a planet with less mass than Earth, we would weigh less than you do here.
For example; A 100lb man would weigh around 107lb on Saturn and weigh around 91lb on Venus.
This is caused due to the different gravitational pulls of the planets.
The field of development of gravitational theory is marked by the brilliant works of great scientists, Isaac Newton and Albert Einstein.
Newton’s classical theory of gravitational force held sway from his Principia, published in 1687.
These principles shifted a little after Einstein’s work in the early 20th century. The theories put forth by Newton are sufficient even today and are widely known by most people.
However, his theories fall short during the most precise applications.
This is where Einstein’s theory plays a key role in moving forward research and conversations about the same.
Einstein’s theory’s significance lies in the deviation from the classical theories put forth along with its implications for further growth in physical thought.
In context to our universe, gravity plays a large role in its fundamental workings. Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth.
The gravitational pull of the moon pulls the seas towards it, causing the ocean tides.
It also is what creates stars and planets by pulling together the material from which they are made.
A specialty of gravity is its power to not only pull on mass but also on the light. It was Albert Einstein who discovered this principle.
This can be easily understood by a small experiment. If one shines a flashlight upwards, the light will grow imperceptibly redder as gravity pulls it.
We can't see the change with your eyes.
Yet, scientists have been able to measure it.
Gravity is a very important concept in the context of Black holes.
They pack so much mass into such a small volume that their gravity is strong enough to keep anything, even light, from escaping.
This highlights the impact that the mass of a body has on the strength its gravity exerts.
We cannot survive without gravity. It is what holds our world in one beautiful, holistic piece.
However, it is interesting to note that even on Earth, gravity is not constant. NASA uses two spacecraft to measure these variations in Earth’s gravity.
These spacecraft are part of the Gravity Recovery and Climate Experiment (GRACE) mission. GRACE detects tiny changes in gravity over time.
These reveal important changes on the planet.
For example, GRACE monitors changes in sea level and can detect changes in Earth’s crust brought on by earthquakes.
Gravity is one of the most crucial parts of physics and our physical world. It is what literally helps us keep our feet on the ground.
A man sitting under a tree was hit by an apple.
The juicy red apple had fallen from a tree right above him.
Instead of eating that apple, he sat and wondered, what makes this apple fall down and not go up?
Does the ground have a magnet or some kind of a pull?
The man then wasted no item and started his research. Eventually, Newton, the man sitting under that tree, discovered gravity.
Gravity is one of the fundamental forces in space which affects everyday objects.
But, What is Gravity?
Gravity or gravitation is a universal force that exists between all matter.
While gravity is one of the weakest known forces in nature, it is also one of the reasons why the solar system and the universe doesn’t collapse.
On Earth, every single matter weights a downward force of gravity.
This is proportional to its mass. It is an invisible force that bodies or objects have to draw other objects to their center.
The gravitational force is also what keeps the planets in orbit when they go around the sun.
Humans being able to walk on earth without flying away is an example of gravity.
You can witness the effects of gravity or the pull of gravity in your everyday life.
Every time you walk, every time a leaf falls or you drop a ball- all of these are due to gravity.
Every object or anything that has mass will also have gravity.
What Factors Affect Gravity?
Mass: The more the mass of an object the greater its gravity.
Watch a paper fall from the balcony, and then look at a stone falling from the same balcony.
Which one falls faster? The stone.
This is because the stone has a greater mass and thus, more gravity.
The gravitational pull between the stone and the ground is stronger making it fall faster.
Distance: Another factor that determines the gravitational force between two objects is the distance between the two.
Gravity weakens with distance.
Objects closer to each other will have a more gravitational pull.
How is Gravity Measured?
Gravity is measured by the acceleration of gravity that it provides to freely falling objects.
The acceleration of objects that fall is what makes its gravity.
At the Earth’s surface, the gravity is about 9.8 meters per second.
This means, that every second an object is in free-fall motion, the speed of that said object increased by 9.8 meters per second.
On the surface of the moon, the acceleration is 1.6 meters per second.
How Does Gravity Work?
To understand the gravity and to explain gravity one needs to know how it works.
However, it is not quite easy to understand how gravity works.
Even two of the most renowned scientists- Newton and Einstein, have two different definitions of gravity and how it works.
There are a few definitions of gravity.
Newton’s Theory
Isaac Newton is the physicist who first discovered and worked on the concept of gravity.
Newton’s Theory of Universal Gravitation says that gravity is a predictable force and all the matter in the universe will feel its effect.
a. It is believed that gravity is a function of both mass and distance. The theory popularised the concept that every particle of a matter attracts every other practice.
b. You can think of it as: The particles of the Earth are attracting the particles of you. The law of gravity states that the force in this case is directly proportional to their masses and inversely proportional to the distance between them. These two factors are also called the laws of gravity. The definition of gravity in physics is also the same as this one.
c. Newton's discovery is also called the law of gravitation or the theory of gravitation.
Einstein’s Theory
Einstein’s theory on gravity is different from that of Newton.
His theory is part of the famous General Theory of Relativity.
Einstein didn’t see gravity as a force at all. It said it was the fourth dimension or distortion of time and space itself.
a. Einstein believed that gravity is a curvature of space. His theory goes much deeper into the concept of gravity and time and space. It moves beyond the simple definition of gravity.
b. There are other theories on gravity and how it works. Some scientists have said that gravity is nothing but particles and waves. Another says that the practices called gravitons are the ones that attract each other. However, gravitational waves and gravitons have not been seen to date.
The Black Hole
The black hole that exists in space has such a high amount of gravitational pull that not even light can escape from it.
This wonder of space has such a strong force that it can suck and absorb any object that passes by it, due to its huge gravitational force.
Since no light can escape a black hole, people cannot see it with their bare eyes.
A black hole exists when the matter is compressed in a small space, which increases the gravitational force greatly.
Why Does Gravity Exist
Gravity is still a mysterious phenomenon to most scientists.
They have still not been able to come up with proper reasoning, as to why it exists and where it comes from.
Gravity is an invisible pull or force that attracts objects to each other.
The gravitational pull in the moon is different from that of earth.
Thus, you will find astronauts on the moon weigh lesser, and are also able to jump higher.
There is much more research that needs to be done to fully understand the concept and characteristics of gravity.
However, without gravity life on earth would not have been possible, at least the way we know of it now.
Gravity is the exceptional invisible force that binds us together and keeps us grounded.
