Skip to main content

The ultimate speed limit - Light, and why is it so

The movie Interstellar reinvigorated my childhood curiosity about the natural world.  Questions and wonder overwhelmed me.  My favorite subject during school and college was Physics.  I still love it and regularly read the new findings.  Interstellar got me thinking on many of the phenomena we don't observe; like what makes certain materials transparent and others opaque.  Why is the speed of light limited to ~3,00,000 km/s, what does empty space exactly consist of etc. etc.  A lot of thoughts came rushing.

I picked up a random one, why does light have a speed limit, what is the constraining factor?  I tried reading online and asked questions in science forums (like StackExchange).  Upon reading multiple sources, the response left me in awe.  Something amazing happened when stuff travelled through space.
A short answer to the question is:  The speed limit is not that of light, but the medium in which it is travelling.  This implies that ~3,00,000 km/s is the speed limit of the vacuum through which light travels. 

Long answer; all I thought I new about space and vacuum was inadequate.  To explain, let me draw an analogy with a compute memory hard disk.  Those of us in Computer Science would know that there is nothing like empty memory.  When we buy a hard disk of 1 terabyte space, the memory is not actually empty.  It has some junk data that is de-referenced.  Or in other words, when we delete a file from our computer, it is de-referenced from the objects in the system.  No memory location can point to the deleted area, but the data still resides there (Even after it is deleted from Recycle Bin, in Windows' parlance).  This is a security concern, as anybody with a physical access to the hard disk can extract the data.  Anti-Virus companies came up with a solution of shredding the memory.  This process basically overwrites the memory location with junk data, so the deleted data is lost permanently.  The important point here is that memory has to contain something if it has to exist, or there is nothing like empty memory.

This logic applies to vacuum as well.  Nothing can be empty in the universe.  Even space which seems empty  is a plasma of annihilating particles.  And this plasma has certain properties, one of which is the maximum speed of any form of energy travelling through it (remember, matter is a form of condensed energy).  This is what limits the speed of light.

Let me draw another analogy; let's say you are travelling from Pune to Mumbai, an average distance of 150 km.  You are travelling at a speed of 600 km/hr.  Assuming there's no traffic, you should reach your destination in 15 min.  But there are toll booths in between, which limit your minimum time.  If there are total 3 toll booths and each take up 5 minutes, then at any speed you won't be able to reach your destination before 15 min.  Similarly, there are electromagnetic doorways in vacuum space, which restrict the speed of any form of energy travelling through it.  Even though I can travel at infinite speed between these doorways, I will have to wait at the next door way until it opens.  I got goose bumps even typing this.

What this means that in a parallel universe, there might exist such pockets where space and time geometry is such that it allows faster than light travel, without worm holes.  Scientists are exploring such possibilities.

This is a very naive explanation to a very complex phenomenon.  But that's the challenge, if I can't explain something in simple terms that a layman does not understand then it means that I myself do not understand the concept clearly.  It's wonderful exploring how complex the mundane phenomena around us are. 
Post a Comment

Popular posts from this blog

Days of our lives at Work and Workplace

Let's talk about Work and Workplace.

We spend around 40-45 hours a week at work, considering a 5-day work week.  It amounts to 26.7% of our week.  Over a long stretch of time, we must be spending at least 25% of our LIFE at work.  That's a quarter!  And considering we sleep for around 30%, work amounts to 38.1% of our conscious lives!

Those exclamations aren't just out of place.  It struck me like a brick.  It is common knowledge, but there is a difference between knowing something, realizing it and it cutting through your conscious.  It was an unnerving realization.  If I am miserable at work, I am unhappy for a quarter of my total life, and more than a third of my conscious life! That's 5 years in an active carrier of 20 years.

I went meta to understand what caused this sudden surge of spirituality; I concluded it could be mid life crisis, a time when career, personal life and unrequited dreams surface from their graves.  However philosophical it might seem, I gave …

Ola and Uber - An Experience

I have been using either Ola or Uber for my daily commute to work for the past few months.  I had a conversation with Drivers quite regularly, ranging from Politics to Movies.  I became interested in how their experience with Ola or Uber was like and how they felt about their customers.  They shared some funny and some scary incidents.

Some points that were repeated way often:

1.  Ola's business model does not help drivers, almost to the point of being predatory.
2.  Ola passengers (yep, us) are quite rude and demanding.  Uber's passengers are relatively more accommodating and polite.
3.  Ola's app is unstable, clunky and crash prone.
4.  Uber's initial plans for drivers were awesome, not anymore.  Less payout nowadays, but still better than Ola's (Uber suffered $780 million Losses this FY)
5.  Uber's app is super accurate and robust.
6.  Passengers don't understand the concept of Uber Pool/Ola share.  They just look at the low price, but don't grasp…

Space as The Final Frontier - The ultimate High

Movies like Interstellar or 2001:A Space Odyssey always make me feel insignificant and hopeless.  It leaves me in despair.  But also accompanying it is a sense of grandiose and greatness, it's a mixed and confusing feeling that feels like an afterglow of a drug binge (metaphorically), quite difficult to put in words or even describe orally.

What I can describe, though, is the sense of adventure and camaraderie I feel towards humanity and the earth after watching those movies.  We don't take Elon Musk seriously enough when he says that humans need to be a space faring civilization.  We cannot leave all our eggs in one basket, aka the Earth.  There are very high chances of a global extinction event over a long period of time.  It could be caused by anything among disease, war, extra-terrestrial objects hitting the Earth, climate change, a gamma ray burst etc.  It's a question of 'when' and not 'if'.  And as the current species roaming around aimlessly on th…