SPACE- TIME from eyes of NEWTON and EINSTEIN

We think our world as filled with stuff like buildings and cars, peoples and buses and nowhere it seems apparent than a crowded city like Kolkata or Mumbai. yet all around the stuff that makes up our everyday world is something just as important but far more mysterious, THE SPACE in which all this stuff exists.

To get a feel of what I am talking let’s stop a bit and imagine, what if we took all the stuffs away like people, buildings, cars and not just that but the earth itself, what if we took away all the planet, stars and galaxies and not just the big stuff but the tiny things too down to the very last atoms, what if we took all away, then what will be left. The obvious thought most of us will have is nothing which is very much correct but strangely we are also wrong, what’s left is just empty space and as it turns out, the empty space is nothing but something that has hidden characteristics as well the stuffs in everyday life. In-fact space is so real that it can Bend, Twist and most important of all it can Ripple. So it is so real that empty space itself helps shape up all the things around us and forms the very fabric of the cosmos.

Most of us have a thought that the outer space is a place that is far -far away but interestingly and actually it is everywhere, in-fact we can even say that space is the most abundant thing in universe.

BUT WHAT EXACTLY IS SPACE

Space in true sense looks like nothing, so how do we make sense about something that looks like nothing, thus leaving the question unanswered and also makes it one of the deepest mysteries in physics. Fortunately, we are not completely in dark, as for centuries our ancestors have gathered clues about the space, some of the earliest was to how object moves through the space.

To get a feel of this let’s assume a skater as she glides across the ring ,in doing so she is moving in relation to everything around her, as she begins to spin not only she can see that she is spinning but also she can feel it because as she spins she feels that her arms are pulled outward Now imagine a situation in which in which she is spinning in empty space (we will take all the stuff around her from the ring to the most distant galaxies, so the only thing is left that the skater spinning is completely empty space).In this situation if the skater still feels her arms outwards , she will know she is spinning. But if the empty is nothing then what she is spinning in relation to?

Now imagine yourself as a skater. When you look out you aren’t seeing anything it just uniform still blackness all around you and yet your arm is being pulled out wards then one question would have strike you that what could I ‘be spinning with respect to?

Is there something out there which I am not able to see?

Trying to answer this question many scientists came up with different ideas and theory thus bringing out different dimensions of space i.e. a bold new picture of space with the basic concept of all was to make something out of nothing.

Sir Issac Newton the father of modern Science pictured the space as the frame work of everything that happens in the cosmos, the arena the drama of universe plays out and Newton space was passive absolute eternal and unchanging the action couldn’t effect stage and stage couldn’t effect the action.

By picturing space in this way Newton was able to describe the world as no one had done before, his unchanging stage allow us to understand almost all the motion we can see around us yielding law that can predict everything from the way apple falls from the tree, to the path earth takes around the sun, these laws works so well that we still use them to in many fields such as from launching the satellite to landing aero-planes and the laws all hinged on one radical idea that SPACE IS REAL. Even though we cannot see it or smell it or feel it or touch it, space is enough of a real physical thing to provide a bench for certain kind of motion like that skater.

A skater in a NEWTONIAN -Space

Newton stage was a huge hit and even enjoyed limelight for about 200 years, but in early decades of 20th century a new set of ideas emerged that shook the very foundation of Newton’s Stage. These ideas were profound by a young clerk who worked in a Swiss patent office, His name was Albert Einstein, Einstein was fascinated by light (not the light bulbs in street light or at home but the very nature of the light itself) and this fascination with one particular weird feature of the light i.e. its speed, that lead Einstein to overturn Newton Picture of Space.

To See how let’s take an example of a moving car which is moving with a speed of 20km/hr., to go faster all the driver has to do is to put the pedal on the accelerator and the speed changes. Now the person sitting in the car feel the changes but also can see the car’s speedometer or speed camera placed on the roadside, now let’s imagine instead of measuring the speed of the car you have the speed cam which measures the speed of the light coming out of the headlight of the car, that camera can measure the speed of the light as 300000 km/s. Now when the car starts moving the rider things that the speed of the light will increase by the same amount as the car after all will give an extra push, but surprisingly that’s not what happens, the speed can or any measurement of light by any precise instrument can measure the speed of light as 300000 km/s., whether the car is moving or not, but how could this be, how could all measurement of the light always came out be same.

So here is how Einstein made sense of this extraordinary puzzle, knowing that the speed is just the measure of space that something travels over time, Einstein proposed a truly stunning idea that space and time could work together constantly adjusting by exactly the right amount so no matter how fast you might be moving you measure the speed of light and its always comes out to be 300000 km/s.

If space and time being flexible sounds and familiar it only because we don’t move fast enough in everyday life to see it in action but if the car would move near the speed of light then the effect will no longer be hidden,

Assuming a car moving with the speed of light the space outside the car will be somewhat like this

For example, if a person is at the street corner watches the car with the speed of light, then the person will see space adjusting so that the car will appear just few inches long and the person will also hear the watch of the driver might be ticking of the time very slowly but from the driver perspective inside the car the watch of the driver will be ticking normally and the space in here will appear as it always does.

Space has been adjusted so that the car will appear just meters’ long

But when the driver watches outside the car he will see the space wildly adjusting all to keep the speed of the light constant.

Car driver's perspective as he watches outside the car, when car is moving with the speed of light

This notion that space and time are unity is one of the greatest insights that have occurs in science, it is so counter intuitive that everything that we have experienced as human beings, and in the hands of Albert Einstein this new picture will solve the deep mysteries having to do

with the most familiar force in the cosmos, GRAVITY.

Newton knew that the gravity is a force that attracts objects to each other and its law predicted its strength of this force with fantastic precision, but how does GRAVITY actually work? How does Earth pull on the moon across hundreds of thousand miles of empty space?

They behave after they are connected by some kind of invisible rope but everyone knew that wasn’t true and Newton law provided no explanation.

After Puzzling over this problem for more than a decade he reached with startling conclusion, the secret to gravity laid in the nature of space- time, it was even more flexible that he had previously realized it could stretch like an actual fabric; this was truly radical break through.

Now to understand further assume a snooker table with some snooker balls on it and assume the snooker table is space time and the balls are the objects in space,

Assuming snooker table as space- time fabric

Now if the space time is nice and flat like the surface of the table object will travel in straight line but if the space is like a fabric that can stretch and bend and after putting something which is heavy on the stretchy space time fabric, Now if the ball is played again the ball will travel along the indentation in the fabric that the heavier object creates and Einstein realized that how gravity actually works it’s the wrapping of space-time caused by the object within it, in other words Gravity is space of space time itself . The moon is kept in the orbit not because it is pulled to the earth by some mysterious force but rather because it rolls around the curve in the space time fabrics that the Earth creates.

Gravity acting between Earth and moon and are explained with the help of Einstein’s Space Time Perspective

So for Einstein the space is not only became real but also flexible, so suddenly space has property, suddenly space has curvature, suddenly space has flexible kind of geometry almost like a rubber sheet and it opens up the whole new way of thinking about the reality and describing the entire universe.

So to conclude this we can say that Newton saw the space time as a passive and unchanging while Einstein saw as a dynamic, its over whelming with time and its dictates how things move, so after Einstein Space can no longer be thought as a static space, it’s an actor which plays a leading role in the drama.

And finally presenting you two perceptions of our two greatest scientists.

Space from Newton perception

Space-time from Albert Einstein perception