Let's Learn Something Cool - How Does Gravity Work

In yesterday's episode, the trolls explained very roughly why gravity is weaker on the moon than on the earth. But do you really know what gravity is and how it works?

(Image source: pexels.com)

Is it the magnet that pulls us on the earth?

Kind of. Gravity is defined as the mutual force applied between two objects and it's proportional to the masses of the objects and inversely proportional to the distance between them. Even simpler, gravity is the attraction between two objects. It's stronger when their mass is bigger and the distance between them is shorter. 

The formula is simple:

F = G * m1 * m2 / d^2  

Where F is the force of gravity AKA weight (in N), G is the universal constant of gravity (6.67 x 10^-11 N m2/kg2), m1 is the mass of the first object (in kg) and m2 the mass of the second object (in kg), d^2 is the square of the distance between the two objects (in m).  

(Image source: commons.wikimedia.org)

On Earth the force of gravity can be given from the formula below:

w = m * g

Where w is the weight (in N), m is the mass (in kg) and g is the acceleration of gravity (9.8 m/s²).

Who said all that?

The first one to describe gravity, was Sir Isaac Newton in the 17th century. Almost three hundred years ago later, another brilliant mind, Albert Einstein, came to support that gravity is not a force, but rather a distortion within the space-time (that's another loooong story).

Does it work the same everywhere?

Well, since gravity depends on the mass of the objects, it cannot be the same on other celestial bodies. The moon, for example, is smaller than the earth, so the force of gravity will be less on it. Jupiter, which is a giant in our solar system is expected to apply greater gravitational force, but this is not the case. Being a gas giant, its density is significantly lower meaning that gravity, although stronger than the earth's, it's not as strong as most people would expect (only 2.528 g - 24.79 m/s²).

(Image source: pixabay.com)

How is it helpful?

Gravity is vital for the balance of the universe. It's what keeps all celestial bodies into orbit, it's the generating cause of our solar system (and not only ours). Thanks to gravity, our atmosphere stays right in place, we don't float into space and to put it shortly, in a world without gravity there would be chaos. Consider it as the glue that keeps the pieces of the universal puzzle together.

Although certain animals and machines seem to "defy" it, gravity is still there. Birds and planes fly, spaceships escape into space where objects float. This doesn't mean that gravity seizes to exist. It's still there hiding, weak but always present. Believers could say it's like God (you can find it everywhere, flooding every nook and cranny and preserving the good function of the world).

Confusing weight with mass

Lots of people tend to confuse the terms mass and weight. Weight is the force that we're being attracted towards the earth, whereas mass is the amount of matter in our bodies. When we say we gained weight, actually we have increased our body mass and this means that the gravitational force between us and the earth has become greater. If you can't fit into your old jeans on earth, although your scales would give you a smaller number on the moon, your jeans would still not fit you...unless, of course, you could condense your body to increase its density by lowering its volume, but so far no dietitian has successfully come up with such a plan :P 

(Image source: pxhere.com)

Let's revise what we just read:

References

science.howstuffworks.com
van.physics.illinois.edu
earthobservatory.nasa.gov
spaceplace.nasa.gov
universetoday.com

Thank you for stopping by and giving this post a read. I hope you enjoyed it! If you please, feel free to pay a visit to my blog and check out my short stories along with plenty of educational posts and of course my bizarre natural phenomena series.

Until my next post,
Steem on and keep smiling, people!