Destination: Black Hole

I like black holes. I like them a lot. They are in the top ten of my bucket list of destinations if I live for a thousand years.

Seems Legit

Seems Legit

Black holes in popular culture are notorious for being very dark objects. I will try enlighten the readers about their shady origins, and hope that people see them in a better light.

Stars run on hydrogen. In the extreme temperatures in their cores, hydrogen nuclei fuse explosively to form helium nuclei. The explosive energy released opposes the force of gravity of the star on itself. Thus the star continues its merry existence, until it runs out of juice, that is. When there is no more hydrogen left to fuse, the temperature at the core decreases, gravity takes over and the star contracts. The contraction again heats up the core to a level where helium fuses into carbon. This reaction is much more powerful than hydrogen fusion, and the explosive output causes the star’s shell to expand, making it a red giant.

If the star is less that 10.5 solar masses then it sheds its outer layers leaving behind a very dense white dwarf star made of oxygen and carbon. the white dwarf star is prevented from collapsing further by the electron degeneracy pressure. However, if the mass of the white dwarf is more than about 1.4 times the mass of the sun, even electron pressure cannot hold back gravity. And so the electrons fuse with protons to become neutrons, thus forming a neutron star. A neutron star achieves stability due to the quantum degeneracy pressure (that particles simply cannot have the same state and so must remain separate).

However, if the mass of the neutron star exceeds 1.5 to 3 solar masses, it collapses again into one of several exotic remnants, one of which is the black hole.

starlife

Source

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Famous Astronomers and other Stuff

astronomers lives

There are 5 scientists that are recognized as major astronomical figures in Europe:

Of the 5 of these people, 3 of them were alive and active at the same time (Galelio, Kepler and Brahe).

Nicholas Copernicus, in particular contributed a lot to out understanding of the Solar system. It was he who popularized the idea of a Heliocentric model of the solar system. He gave a series of assumptions which explained things such as Sunrise, sunset, star motion, retrograde motion etc. Even though some of his assumptions are incorrect according to modern science, they were still such good approximations that all that was needed was Galileo’s little struggles to put the final nail in geocentric theory’s coffin.

During his time, the world was undergoing some serious changes. The Americas were discovered in 1492, a discovery that literally changed the face of the earth (according to humans, at least). In 1526 King Babur, the great grandson of Tamerlane defeated the Lodhi Dynasty to establish the mighty Mughal Empire in the Indian Subcontinent. His victory marked the first use of cannons in India (that was why he won, mostly). While Copernicus was busy reforming our view of the universe, William Shakespeare (1564-1616) was writing what would become one of the most recognized pieces of literature in the world. He is considered to be the greatest writer in English language and a trendsetter in literature of many other languages as well.

What I found so interesting was how differently I perceived scientific history from political history. Comparing astronomers to Columbus’s voyage makes astronomy seem really old (and the Americas really new). It was also a surprise to realize that the heliocentric model of the solar system was proposed before such a famous Empire was formed. Now the Taj Mahal seems like it was built yesterday.

To Stretch or Not To Stretch

Physics has the distinction of hosting the one of the weirdest concept hierarchies  Don’t get me wrong: physics is beautiful in its intricate connections. But sometimes, especially in the case of modern physics, one feels something like:

WTF_1

So, most of us know about special relativity. A quick summary for the unfortunate: Special relativity establishes the speed of light as constant in all inertial reference frames (that is, for all observers who are either at rest or moving at a constant velocity). One of its implications is that information (in the layman’s case:anything) cannot travel faster than light. This means that as one starts approaching the speed of light, stuff starts happening. Time slows down (according to an outside observer looking at you), your mass increases and weird lighting effects start taking place. I am concerned with length contraction: the shortening of length of objects which are moving at relativistic velocities.

After an unexpected abortion of its hiatus, my conscience prevented me from playing Ace Combat.  And so I was looking for something productive to do when I found this website. According to the article, even though relativistic speeds may cause measurable shortening of length, it most certainly is not observable. Instead the fast travelling object will actually “appear” elongated, while actually being “contracted” at the same time (Schrodinger’s cat, anyone?).  The more I progressed into the article, the more I was like:

WTF_2

But then, I went into scientist mode…

inception_meme__1_…and decided to do a little calculation of my own.

 Imagine there is an object moving towards you at a velocity ‘v’. The stationary length of the object is ‘l’. The distance between you and the farthest part of the object is ‘x’.

rel_exp_1

Just by looking at the image we can see that light from the back of the object takes longer to reach the observer. Mathematically:

t_back_eqnt_front_eqn

We also know that we see an image when photons belonging to the same “plane” reach our eyes. From the equations above, we can see that photons reflected from the front “l/c” seconds later will arrive at the same time (i.e. on the same “plane”) as photons reflected from the back. However in ‘l/c’ seconds, the object will have moved by the distance:

dist_eqn

So the image that will reach our eyes will be like:

rel_exp_2

The apparent length of the object will be:

obs_enlrg_fac_eqn

Let us now assume that the object’s velocity is actually relativistic. So the measured length of the object will shrink to:

rel_len_eqn

And it is this length that will undergo apparent distortion:

final_stretch_eqn

Where l(measured) is the stationary length of the object. The relativistic factor shrinks whereas the observational factor stretches the object. It all comes down to which one of those functions is more powerful. This is a graph of enlargement vs. speed. ‘1’ on the y axis represents no distortion.

plot_rel_factors

Back to Ace Combat. ibrahim2016 out.

Twinkle Twinkle Little Planet

Sounds wrong because the extra syllable blemishes the aesthetic quality of the symmetry of the rest of the poem.

trollface

Planets do twinkle, in fact. Its just that we do not notice. And it is the hallmark of a truly good (and bored) scientist to correct a misconception, even if it is only superhuman vision that can salvage the fallacy.

The atmosphere is a sea of air. Air is a fluid. Which means it is not vacuum. Therefore it has a refractive index. The density of air changes with altitude, so the refractive index also changes. Any light that enters the atmosphere (except from the normal vector, obviously) is bent.

Stars are very far away. They are so far away that they appear as point sources of light. So if we were to draw a ray diagram for a star, we would only need a single line to denote star light. It so happens that due to the constant ‘flow’ of the atmosphere, some times that star light is refracted so that it momentarily does not reach our eyes. That is called twinkling.

Simulation

Simulation

Planets are not that far away. Since they are nearer they can be resolved as light sources with a dimension. So a ray diagram for a planet will have multiple lines denoting light coming from different points on the planet. That light is also bent the same way as star light. And individual rays also sometimes bend enough so that they do not reach our eyes. But there are enough rays that do reach our eyes that we do not notice the slight change in the planet’s brightness. Hence we do not notice the planet twinkling.

Image Source

If Light Travelled Really Fast…

According to prevailing theories in Physics, the speed of light, denoted by ‘c’ is a universal constant. It means that it is intrinsically related to the very nature of the universe. We exist because we are the culmination of almost fourteen billion years of conformation to this value by every single one of the atoms in the universe. So what I am about to write is pure conjecture. The consequences of the minutest change in ‘c’ will lead to fundamental reformation of the universe and even a Dumbledore/Voldemort/Gandalf/Chuck Norris mutant wouldn’t be able to prevent you from not existing.

Having placated any fundamentalists out there,let us imagine then that the speed of light increases exponentially one fine morning but the change strangely refuses to harm the wise homos on planet earth. Let us also exercise tradition and ignore the fact that the universe is literally falling apart. Now then,

1. David Blaine would become homeless

If you don’t know who he is, I salute your choice of TV content. But for the sake of this article, let me explain: he is a illusionist who sometimes does levitation tricks. Why would he go out of a job? Because everyone could levitate if light was really fast. You would still not hold a candle to Superman but you would be able to fly in a very crude sense. That’s because the speed of light is directly related to the electromagnetic force. It is the force that repels the atoms of the earth and your body from merging together. So if the speed of light increased, that force of repulsion would increase and stuff would literally start to levitate.

2. You would become really hot and World Peace will be in jeopardy

That’s it, that’s it. Don’t get your hopes up. I meant literally. And the ‘and’ was not intended to indicate causality. It was more in the flavor of: a goat and a microwave. Anyways,  a greater electromagnetic force would mean that chemical/nuclear reactions would become more ‘vibrant’. The reactions that require lots of energy to start would need even more energy. But the ones that release energy, well lets just say if someone decides to pull another Hiroshima it would vaporize the earth’s atmosphere. Back to hotness, so the human body also burns up chemicals for energy. And that burning up is exothermic. And it would be so vigorous that you would feel as if you are on fire. The up side is that you wouldn’t ever feel cold again.

3. Dragon Ball fans will have a field day and Master Chief will lose his edge

shockwave_punch_small

Okay, just ignore everything but the fist.

With your body’s chemical burning being so over-productive, your muscles will become really powerful. You will be able to run faster, jump higher and strike with lightning speed. And the increased repulsive forces between you hands and the air molecules will allow you to create a shock-wave of awesomeness with every punch in the air.

4. Star trek will reboot as a reality show

The enthusiasm of exothermic reactions will also apply to fuel. Cars (or perhaps levitation pods) will become very fuel efficient. So will rockets, thus reducing cost of space travel. You could actually go to mars on the same fuel that you now use to go to your grandma (who incidentally might be moonlighting as a ninja, given the circumstances). Whats even better is that you could reach and even exceed the old speed of light using conventional means. So interstellar travel will become a very possible possibility.

5. But in reality…

Stars wouldn’t exist. Nuclear fusion, the process that runs stars, happens when two atoms over come their repulsion and fuse to release energy. But then the repulsion will be so high that atoms wouldn’t even want to come close to one another. Since there will be no stars, there will be no supernovas that release heavier elements (including carbon) into the universe. Had the speed of light been faster since the big bang, we would not even have existed. There would be no black holes since the speed of light will be too large to be captured by the gravity-well of any body. So any dreams we might have of making a shortcut through space time to achieve time travel or actual FTL communications will be quashed.

I’ll end with an awesome limerick:

There was an old lady called Wright
who could travel much faster than light.
She departed one day
in a relative way
and returned on the previous night.

3025-if-you-know-what-i-mean

 

If light travelled really slow…

The speed of light is one of the fundamental constants in the universe (along with the Gravitational constant, permitivitty etc.). Changing any constant even slightly will have deadly consequences. But if we manage to survive (somehow), we would find ourselves in a very ‘interesting’ universe.

The constant for the speed of electromagnetic waves ‘c’ has a value of 300 million metres/second. Imagine that some one hacks the universe’s secure servers and changes ‘c’ to 1. The following is a roughly chronological list of things that would happen in a universal conspiracy to end the human race:

1. We would shrivel up and die

Literally. The speed of light is directly related to the strength of electromagnetic force. This is the same force that prevents you from falling out of your house when you lean against a wall, or from falling through a chair while you are sitting. It also helps you keep you in shape while gravity is doing its best to pull you to the ground. If the speed of light were to suddenly decrease by several orders of magnitude, all matter (or most of it) would start to collapse under its own gravity. The world would literally shrink out of existence.

2. The sun would go out

Again: literally. As matter collapses under its own gravity, its gravitational pull on the surface increases and stuff like rebellious atoms and people who can afford a rocket will need higher speeds to escape a body’s gravity. Eventually the ‘escape velocity would exceed the speed of light. And since classically one cannot productively travel faster than light, including light, all matter with high escape velocities would become black holes, including the sun and the earth and all the planets in the solar system.

3. Time will s l   o    w     d       o        w          n

If by any miracle we are still alive we will notice (that’s putting it subtly) that everything has shrunk. The gravitational field will be extremely strong. And since light is so slow, our every motion will be at relativistic speeds. That means that on a jolly morning when I decide to go out for a walk, I might as well come back to my house to find it in ruins from age. In other words we wouldn’t need to wait an entire week for new episodes of our favourite shows.

4. The world will look W13rD

Take a look at these pictures:

Light captured at super high frame rates,

Light captured at super high frame rates,

Simulated reflection of light at super slow motion.

Simulated reflection of light at super slow motion.

This is what light looks like if it is slowed down. On a post-hacked universe, you could stand behind something heavy and literally make copies of yourself (gravitational lensing, kage bunshin no jutsu! for Naruto fans). Since light will bend under extreme gravity, you will be able to see whats happening on the other side of the earth, or the back of your head for that matter. You could swipe your hand through the ‘air’ and turn your palm into a black hole and deflect bullets with a wave of your hand.

All in good time. In the real world we would just stop existing the moment a single constant was changed. If all universal constants were scaled down proportionally, we might have a chance, but alas we don’t even know all of them. So why did I conjure images of a Matrix/Naruto/Avengers/ Harry Potter universe? Simple. I just got carried away.