If you want to lose those extra 5 pounds, you could get farther from Earth. Spacetime and what its got to do with your weight.
The mystery of Gravity and the conundrum between two of the most famous scientists of all time.
It all started with a bright red fruit and a brilliant young mind. Sir Issac Newton made sure he went down in the history of humankind as one of the most renowed physicists the world has ever seen after formulating his famous Gravitational theory in 1665. According to this theory, there exists a mysterious force between two objects having mass.
Although Issac Newton didn’t know why such a mysterious force existed, it became one of the most famous theories of the century and many centuries to follow. The theory successfully explained why the planets move in orbits they way they do around the sun, and why we moon revolves around the Earth.
The formula deriving the force of Gravity is determined by several factors all bundled up into a neat little equation as the one below.
m1 : mass of object 1
m2 : mass of object 2
r : distance between the two objects
G : constant value
We don’t have to worry about the details too much but what I want you to understand that as the mass of the objects gets larger, the gravitational force between them gets larger. As the distance between the two objects gets tinier, the gravitational force gets stronger and vice versa.
But why does this force even exist. Just because an object has mass why should it have Gravitational Force aka Gravity? A little later down the road our brilliant Albert Einstein came up with something i bet you’ve heard about. It’s called the General Theory Of Relativity and I’m here to help you make sense of it.
Instead of thinking about space as something rigid, let’s familiarize ourselves with the possibility that space has some sort of ‘curvature’ to it. A little flexibility which allows space to warp the space around it. Does it make a little sense?
Lets look at this example.
The first picture shows us space in its normal state. Rigid. Unflexible.
The second picture shows us space when an object with mass is added to it. The mass of the object warps the space around it giving it a ‘curvature’.
Although most representations show you a 2D sheet bending like the one above it’s actually 3D space around the object making it bend. This is just easier to depict so that’s why its used so often. A more accurate representation of the bending of Space would be the little animation below.
This ‘bend’ pulls objects closer. This is the gravitational force Newton was talking about. Sir Issac Newtons’ formula for Gravitational Force still applies but this notion or interpretation rather of space and the curvature of space brings us into the light on why such a force even exists in the first place.
Since we’re closer to the Earth, the force we experience is a result of the curvature of spacetime, andd a direct implication on your weight. If you’re closer to Earth spacetime is ‘curved’ more — so you weigh more. So, potentially the people who live on the floors above you — weigh less than they probably would on the floors beneath them, but this difference is super tiny so a weighing scale wouldn’t pick this up.
A place where you would weigh less, is the Moon. The curvature caused by the moon is less than the curvature of Earth. SO — you’d weigh a lot less than you would on Earth (six times less on the moon than you do on Earth to be exact).
Okay.. so now we understand how gravity works. It’s because mass distorts the space around it pulling space closer towards it, but is space all that it pulls?
The Special Theory of Realativity states that the speed of light is the same for all observers.
So, if light were to travel across the bend from point A to point B it would travel along the bend thus resulting in a longer path. This is because curved lines take up a longer distance than straight lines.
If the speed of light is CONSTANT ( which we know it is ) and the DISTANCE BECOMES LONGER, light needs to MAKE up for the longer path to keep the SAME speed throughout.
How does it do that?
Remember that Speed = Distance / Time
Distance increased so the only way to counteract that is by increasing the time. The speed of light will remain constant through the curvature if the time taken by light to reach point B through the curvature increases.
What does this mean? It means, guys, that time slows down ( increases ) while light passes through the curvature. We can extend this to say that anything passing through a curvature gets slowed down depending on the degree and extent of the curvature.
Thus Space warps around matter and Time slows down around matter.
This creates a medium which alters our perceptions about space in general and introduces us to one of my favourite concepts in physics called SPACETIME.
