Let’s Learn About Gravity | Rare And Intriguing Science News For Students
Do you know that the planets and moons would cease to orbit their parent bodies and drift away in a straight line without gravity?
The gravity is only strong over a short distance, but dark energy is thought to be distributed evenly, preventing gravity from pulling everything back together.
What do we know about gravity?
In short, ‘Nothing.’ We barely even think about it, at least until we stumble on the stairs or slip on the ice.
Most ancient thinkers even didn’t consider gravity a force.
In their words, it was merely the natural tendency of objects to sink towards the center of the Earth while planets were subjected to unrelated laws.
But, there’s more to it. It is one of the four well-known forces in physics.
The other electromagnetism governs magnetism, light, electricity, and a pair of nuclear forces that operate across atomic nuclei’s small distances.
Despite being all-pervasive and crucial for keeping our feet from flying off the Earth, gravity remains a mystery to scientists.
Our knowledge regarding the force of gravity has been evolving since the days of the famous ‘Issac Newton and his apple“- and still, it is!
Whenever we discover anything new about gravity, we tend to see the world around us in a new light.
Gravity: What Do We Know?
Gravity is “the force of attraction between any two masses or any two particles.“
It only doesn’t define the attraction between the objects and the Earth. It is an attraction that prevails between all objects and everywhere in the universe.
Sir Issac Newton (1642-1727) discovered that a force is essential to change an object’s movement’s speed or direction.
He also understood that the force called ‘gravity‘ is what makes an apple fall from a tree or help humans live on the surface of our spinning planet without being flung off.
He also realized that gravity is a force that exists between all objects.
Issac Newton’s law of gravity soon became a mathematical description of how bodies on Earth’s surface are observed to attract one another.
The gravitational equation defines that the force of gravity is proportional to the two masses’ product (m1 and m2).
It is also inversely proportional to the square of the distance (r) between their centers of mass.
F= G m1m2/r2,
Here G denotes the Gravitational Constant. G has a value of 6.6726*10-11m3kg-1s-2.
The effect of gravity extends from each object present in the space in all directions possible and for an infinite distance.
But, the strength of the gravitational force reduces quickly with the distance.
We, human beings, are never aware of the Sun’s gravity pulling, as the pull is so small at a distance between the Earth and the Sun.
Neither are we aware of the pull the lunar gravity has on our bodies, but as per the physicists and science assignment help experts, the moon’s gravity is responsible for all the ocean tides on the Earth.
Here are some particular exemplary examples of the instances of gravity that would help you form a comprehensive idea:
- The force that holds all the gases in the Sun
- The force which leads a toddler to propel down the slide
- The force that leads a glass to fall on the floor when you drop
- The force which helps you walk on the surface of the Earth instead of floating away in the space
Rare And Intriguing Six Facts About Gravity
If you give it a close thought, gravity is also the story of physics, with some of the biggest names of the field earning fame by defining the force that ruled their lives.
However, even after more than 400 years of study, the mysterious force still lies at the core of some of the world’s greatest mysteries.
After countless discoveries, we still don’t know everything about gravity.
That includes the accurate way it fits in with the other vital forces of the Earth.
Here are some of the intriguing and rare facts that we all should know about the primary fundamental force on the Earth:
Gravity is powerful but not too powerful
As we said above, gravity is the weakest of all the Earth’s fundamental forces.
A bar magnet can electromagnetically pull a paper clip upward, defeating the entire Earth’s gravitational force.
As per the PBS’s Nova, physicists have estimated that gravity is 10^40 times weaker than electromagnetism.
In 1798, the British physicist Henry Cavendish conducted one of the world’s first high precision experiments to precisely determine the value of gravitational constant or the G. (Proceedings of the National Academy of Science’s Front Matter).
His estimation of G came out to be only 1% off from the modern-day accepted value of 6.674*10^-11m63/kg^1*s^2.
The brilliant German-American physicist Albert Einstein brought the next revolution in our knowledge of gravity.
His Theory of General Relativity demonstrated that gravity arises from the curvature of space and time.
That implies that even the rays of light, which should follow this curvature, are bent by enormously massive objects.
Scientists then used Einstein’s theories to speculate the existence of the black holes.
In the locality of a black hole, Newton’s law of universal gravitation no longer explains how accurately the objects move.
Instead, Einstein’s tensor field equations take precedence in the case.
The EFE is a tensor equation relating a set of symmetric 4 × 4 tensors. Each tensor has 10 independent components. … The equations in contexts outside of general relativity are still referred to as the Einstein field equations. The vacuum field equations (obtained when Tμν is everywhere zero) define Einstein manifolds.
Gravity remains a perpetual force of mystery for ages
Gravity is such a way that it confuses every scientist in other ways, too.
It is observed to be one of the trending discussions on the physics assignment help forum.
The Standard Model of Particle Physics that explains the actions of almost all well-known particles and forces leaves out gravity.
While light is carried out by a particle called a Photon, physicists remain clueless if there remains an equivalent particle for gravity, which would be known as the Graviton.
However, gravity has still been used to unearth monumental findings.
It was like some unseen mass is tugging on them gravitationally, helping us know a light material now popularly known as the dark matter.
Dark matter is a form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total mass–energy density or about 2.241×10−27 kg/m3.
In the recent era, numerous scientists have also managed to capture another consequence of Einstein’s theory of relativity.
It was observed that the Gravitational Waves emitted when massive objects like neutron stars and black holes rotated around one other.
Since 2017, the LIGO (Laser Interferometer Gravitational-Wave Observatory) has opened up a new window to the universe through the widespread detection of the exceedingly faint signal of such events.
Gravity and weight – Not the same thing
Often we tend to say indolently that astronauts are in zero gravity when they remain afloat on the space station.
But, that’s not entirely correct.
On an astronaut, the gravitational force is about 90% of the force they would experience on the Earth.
But, astronauts are weightless as the weight is the force the ground exerts back on them on the Earth.
Take an example:
If you take a bathroom scale onto an elevator in a big fancy hotel and stand on it while the elevator goes up and down, you would see your weight fluctuating.
Apart from that, you would also feel the elevator accelerating and decelerating, though the gravitational force remains the same.
But in orbit, astronauts usually move along with the space station. They have nothing that can push them against the spaceship side to make weight.
Gravity creates waves that move at a lighter speed
Gravitational waves are predicted through general relativity.
Like, if you have two stars or white dwarfs or black holes locked in the mutual orbit, they gradually get closer as gravitational waves tend to carry energy away.
Earth does emit gravitational waves because it orbits the Sun, but the energy loss is minimal even to notice.
About 40 years ago, we had indirect evidence for gravitational waves, but the LIGO confirmed this rare event in 2016.
Detectors picked up a rupture of gravitational waves produced by the collision of two black holes more than a billion light-years away.
One significant consequence of relativity is nothing can travel faster than light in a vacuum, as per eminent physicists and scientists worldwide.
That applies to gravity, too. If anything drastic happened to the Sun, the gravitational effect would reach us roughly at the same time, just like the light from that event.
Massless particles known as ‘Gravitons’ carries the gravity
In the Standard Model, particles are noticed to interact via other force-carrying particles.
Often students who seek assignment help tend to contemplate or ask us, ‘How is that even possible?”
Let’s give you an example:
You know that electromagnetic force is carried with the help of photons. Right?
The theoretical particles for Quantum Gravity (QG is a field of Theoretical Physics) are Gravitons, and by now, we have definite ideas of how they should work from general relativity.
So, like photons, gravitons are also massless. If they had mass, experiments conducted till now would have observed something.
However, it doesn’t rule out a ridiculously tiny mass.
The quantum gravity appears at the smallest length; anything can be
Gravity is feeble, but the closer together two objects are, the stronger it becomes!
Finally, it reaches the other vital forces’ strength at a too-small distance, popularly named as the Planck Length, much smaller than the atom’s nucleus.
That is where the Quantum’s Gravity’s effects would be strong enough to measure, but it’s too small for any experiment to examine.
People have suggested theories that would let the quantum gravity show up close to the millimeter scale. However, till now, we haven’t seen those crucial effects.
As successful as Einstein’s theory in helping physicists solve innumerable problems in cosmology and astrophysics, it is not the final word on gravity.
The reason is that, until today, no one has yet figured out how to reconcile general relativity with other remarkable physics and quantum physics theories that explain the inner working of the subatomic realm.
We all hope that a complete theory may one day combine general relativity with Quantum Mechanics.
If and when that occurs, we may once again see gravity in a new light or discover intriguing facts on gravity.