Space is arguably one of the most fascinating things in the universe. In the wide space, there are things known as black holes, holes that can literally eat you alive! One of the key parts of these bodies is what is referred to as their event horizon. So today, I’m going to elaborate upon them. Enjoy the ride!
I think we all know what the boundary of place is-Let’s take countries as an example. If you enter a country, you are now inside of it, and you can’t exit without some cost, you will probably need some form of identification and need to go by plane. Now the event horizon is a certain boundary of a black hole-except there is no identification to escape it. Once you enter the event horizon, there is no escaping, you are literally freezed in time. (Oh yea, I forgot to add-the event horizon is USUALLY perfectly spherical)
Woah! Let’s understand that last point. What is the meaning of “Freezing in time” So this touches a weird but fascinating topic.
(Keep in mind- Gravitational Time Dilation – The stronger gravity is, the slower time passes relative to someone farther away from that gravity.
Gravity is EXTREMELY intense in a black hole- especially near the event horizon)
Let me explain this from another perspective-Imagine that you’re watching a spacecraft being sucked in by a black hole (let’s say you have a very powerful telescope). The spacecraft is nearing the event horizon at the point when you’re looking at it. Since gravity is so intense at this point, the spacecraft would seem to move slower and slower, until it seems to just stop or freeze in time.
Now that was your perspective from where you observed it.
But if you were in the spaceship, you have actually not frozen, you are moving deeper in the black hole in a matter of seconds, though you can’t send any signals now.
(Shift in perspective-you are now viewing the spacecraft, once it seems to have frozen in time) Now here is something astonishing-when you see the spaceship “freeze in time”, it won’t be too long until you won’t be able to see the aircraft at all.
Why, you ask?
Well this is one of the strangest things about blackholes.
Due to the intense gravity of black holes, it literally stretches light-something known as gravitational redshift happens.
First the rocket will appear to change colour- it will become red, redder- than infrared (invisible to your eyes), then a whole series of others-until you can’t see it anymore, not because the light has disappeared, but because it has stretched so much that your eyes or the telescope cannot detect it anymore.
(Important Notes-
-it is possible to see gravitational redshift, as long as it isn’t too extreme, in this case it is too extreme to see the light.
– if an object has not yet reached the event horizon, it can still potentially escape the black hole by sending signals or using any power it has. However, none of this is possible if the object has entered/crossed the event horizon.
-gravitational redshift and gravitational time dilation are only from the perspective of the viewer (you). Looking at the object’s (in this case-rockets) perspective, all things seem normal. (There will obviously be a huge difference in other aspects of the ship.)
IMPORTANT QUESTION
Why can’t an object escape the event horizon?
Ans. Due to the intense gravitational pull or the black hole at the point, escaping is out of the equation.
-REPEATING AGAIN- if an object enters the event horizon, it can NOT come out. No matter what. It can’t send signals, use power, NOTHING. Remember that.)
WHY IS IT CALLED THE EVENT HORIZON?
I don’t know about you but whenever I come across a term or definition, the first thing I do is find its meaning and why the certain occurrence was given that specific name. So, Let’s break down this term-
Event-Any occurrence in the universe (Example-A flash of light, an asteroid crashing on the earth; heck even moving your pencil!)
Horizon-the limits of your knowledge or experience OR a limit beyond which you cannot see. (Note- Yes, there is another meaning of the term horizon, however this is the one relating to the topic.)
Smashing/correlating these terms together, we get that when something in the universe crosses the event horizon, its events (its future) becomes unknown or invisible to all of the outside world till the end of time.
Therefore, it is a place where no information from the inside can reach the outside. It’s literally the horizon of events.
(Notes-
-The event horizon is a point of no return
-No information from the inside can reach the outside
-It is the horizon of events)
HOW BIG IS THE EVENT HORIZON?
All black holes are not of the same size. Therefore, nor is their event horizon.
For scientific and research purposes, it is necessary to find out the size of event horizons of various black holes.
(I think this is obvious now, but I will state it just in case-
Smaller the black hole, smaller the event horizon,
Bigger the black hole, bigger the event horizon)
So to calculate the size of any event horizon, there is an equation that we use-
rs=2GM/C2
(C2=CxC)
This equation is the Schwarzschild radius, an equation that was left unsolved by Albert Einstein and later solved by Karl Schwarzschild, leading to the name of the equation.
Now this equation is very, very complex. So, what I will do is explain the formulae briefly so you can know the basics, as knowing the depths of the equation is not necessary to understand the concept (It might also be quite boring for some of you)
Let us break down the different meanings of all the jumbled letters in this equation-
G- G is a number that tells us the strength of the gravity between two objects.
DID YOU KNOW?
If G were just a little bit up or down from where it is, we would not have stars and other fascinating things, we could even float off the earth!
In simple words- it tells us the gravitational force of the universe.
M- M is how much mass the black hole contains. Think of it as all the stuff the black hole has swallowed.
C- C is the speed of light- also known as the fastest thing we know!
Now, a question that you may ask yourself is-
“How are we supposed to know the value of G and M? It is not like we can weigh the universe-or black holes.
The answer, I will once again explain in brief, nothing detailed-
Let’s start with G, the strength of gravity of the universe.
We actually measure G from here on Earth, using many, many clever experiments conducted by scientists of course!
As I said earlier, G is the same everywhere in the universe, not only on Earth.
Let’s move on to M- the amount of Mass a black hole contains.
We obviously can’t measure the weight of a black hole, but we can use a bit of physics and data from surrounding objects to get a pretty close estimate.
As we know, black holes are invisible.
So if stars and/or other celestial bodies are rapidly revolving around something invisible-Its most probably a black hole!
(Another question you may ask is “Why do celestial bodies need to revolve around something invisible rapidly or fast for it to be a black hole?
The answer is that if the celestial bodies don’t move fast enough, they too will be sucked in by the black hole.
This is derived from 2-3 physics concepts (there is no official concept) that basically says
The stronger the gravity, the faster something has to move to stay in orbit.)
So, by watching how fast the celestial bodies move around the black hole, scientists can pretty closely calculate the gravity and thus find out the weight of the black hole.
It’s kind of how you could try to calculate the weight of an elephant by watching the way grass shakes whenever it moves.
Now, you may ask-how the heck do scientists do that?
The answers are in use of..PHYSICS!
This may seem a bit confusing but if you apply certain complex formulas you will eventually be able to calculate M.
So, once scientists have all three variables, they find out the size of the event horizon using the given formulae. Here is the general idea-
The bigger the mass of the black hole is, the bigger its event horizon.
Light speed and gravity just decide how it all comes together!
Possible Question-
Why do celestial bodies even orbit black holes in the first place?
Imagine you’re a star. You spot a black hole, and you can’t just run away. The not-so amazing gravity doesn’t allow that (BOO HOO)
Would you rather orbit it and save your life-though you will have to be very careful about how close you orbit, because you could get consumed by the hole if you’re too close, (In other words-still be scared for life about accidentally falling in) – or get consumed by it? (PS-Ignore what I said in the bracket, it isn’t meant to change your answer.)
I’ll let you decide the answer to that question.
And that’s how to calculate the size of the event horizon! Insane, right?
Well, that’s all for now, so I’m signing out. If you like this essay of mine, I’ll try to do the same with another essential part of black holes, their singularity. Until then, Adios my friends!
Category: Blog
For Anne Gregory – A Perspective
My commentary on ‘For Anne Gregory’ by William Butler Yeats
The poem discusses the topic of love. Love arising from a “young man in despair” and why all he’d ever fall for would be the female’s (Anne’s) golden lovely hair and appearance, not her, her personality. The point arises that the man is young, therefore presumably naive and in despair, therefore hopeless. Does such an immature person deserve the interpretation of being seen in love?
Worse, Anne focuses on the concept of being loved by a man of such sort (for he is labeled as common) to an extent that she’s ready to degrade and undermine herself, ready to make her personality the spotlight of her being, when she should be able to live as herself, letting her beauty be another ornament.
Mother Abbess (The Sound of Music) once said “The love of a man and woman is holy too”, so why? Why is it implied that only God has the potential to love you for who you are? Surely, God is the one who knows you, the real you, but that doesn’t mean that humans are incapable of reaching that extent. Does knowing someone head to toe, past to future define love? Is knowing all you need? For the question arises, what is love?
I’ll try, but sincerely, words are mere. Love is the wind that blows from one to another with scents and history until they are one, it’s unheard and unseen by all others incapable of understanding, the color of their eyes staring into their pools, long enough to merge. Be one. The souls are so well acquainted, they need no words to express themselves, a silence singing everywhere.
And it’s everything, respect, unwavering support, memories, smiles, tears, hope, humanity, poetry, art, dance, nature, life.
Yet, it’s nothing. For what “all” is, is nothing at once. (God?)
So love is larger, love is surrender and victory, love is truce, allies, love leaves only one kingdom, of not an “I” or a “you”, of “us”. It can never come down to a word, a person, a poem, an analysis. And so the interpretation wanders as I hope Anne can go out in the world and feel it, for that is love.
Eclipse of Color
One in a Million
I asked the girl who rode the Moon, and asked what she had seen,
She answered with a couplet which was poetic like a dream.
She told me about the stormy seas where ships would take their last breath,
She told me about the peaceful stream that flowed from the west.
She told me about the scorching desert where camels ruled the lands,
She told me about the freezing ones with white as the colour of their sands.
She told about the wars infinite which were happening in the world which was ours,
The earth which once was lush and green was now being engulfed by the demon of war.
She told me about the air, grey,
Which covered our planet, which once was happy, healthy, blue-green and gay.
She told me how the Earth looked covered by the shadows of evil:
The planet which once looked bubbly and lively,
Now looked grief-stricken, depressed and full of misery.
She told me how the planet had been, voice dripping with nostalgia:
Glorious creatures roaming the place,
Beautiful birds chirping and dancing with grace.
Alas! The only song heard now, was of violence and disgrace.
She told me about a dream she had seen,
Filled with excitement, she had seemed.
She told me about a peaceful paradise,
Where humans had already opened their eyes.
She asked me to take an oath that day,
To spread the message, she gave.
We need to work hard to save the day,
After all, one in a million is the planet in which we stay.
When I Die
When I die,
invite strangers to my funeral
no, not a single person I knew.
Not a single known soul.
For strangers hold more empathy,
more passion,
than anyone else.
When I die,
invite poets to my funeral
not any other soul.
For poets carry compassion
like a candle in a storm.
But when I die,
invite my loved ones instead.
For the poets,
and the strangers,
already live in them
and no one else.
Save Mother Earth
We put the waste in tons
In mother Earth’s calm oceans
And cut the lush green trees
Which provide us with cool and pure breeze
We continue poaching and hunting
The animals which are a blessing.
We pollute the air
Even the atmosphere we do not spare
We keep on burning excessive coal
For which we will have to pay the toll.
Our efforts must endure
To let the environment be pure
As there is always a solution
to reduce pollution.
Everyone, plant just one more tree
Stop hunting animals, let them live in forests free
Get the pollution level checked for your cars
And follow the 3 R’s.
Use solar energy instead of coal,
Stop wastage, make it your goal
Save Mother Earth
Before it is too late
Or else destruction is written in our fate.
Let’s change ourselves without delay
Or it is we who will have to pay.
Phoenix – Rising from the Ashes
The phoenix, a bird of might,
Rises from the cold night,
From the ashes, burnt and grey,
It rises, to face a new day.
Above every challenge it soars,
No matter how hard the rain pours,
Even in the darkest of dark,
Flickers of hope will spark.
So just like the phoenix, get up and rise,
Waiting ahead is your prize,
Don’t give up even if you fall down,
Rise from the ashes, and claim your crown.
Flame of Faith
Flame of Faith
The sky above, painted with clouds,
Dark and grey, arranged in crowds.
They cry and weep, creating sorrow,
Leaving no promise of a bright tomorrow.
The winds blow, fast and fierce,
Mirroring a sorrowful tune, which has played on for years.
The fuel of hope, now runs out,
Leaving a path, filled with doubt.
But look! A beam of light,
Piercing the dark, a ray so bright.
The clouds, now they part,
Reigniting the hope, in my heart.
And now I see a sight divine,
An arch of colours, a cheerful sign.
So stay hopeful my friend,
for the darkness is sure to end.
Then, you will see the brightness following through,
And the flame of faith will start anew.
Grace in the Cracks
We are mosaics, shattered and broken,
Our wounds and experiences, many unspoken.
These bits and pieces, unappealing in the light,
The memories which trace them, something I can’t fight.
There is no beauty in those jagged lines,
Or that is what I thought.
Scars resurface displeasing memories,
And they leave us distraught.
And while that may be true,
They were what we survived.
Those blemishes were what we fought,
Something through which we thrived.
These marks we wear, a badge of grace,
These wounds we have,
A thing to embrace.
For these pieces are joined with gold,
An ancient story, each one of them told.
So, try to accept all these gaps,
And one will find grace in the cracks.
Turbulence
Anger is a two edged sword;
While you aim it to them;
you bleed yourself.
Anger, the turbulence in the limpid waters,
Eager to bring all to dust.
While you plan to kill them so fervently,
Who knows when you shall meet them ever again?
Wrath is the broken piece of glass,
Hurtful and inutile,
you broom it to bin; not pick yourself,
A wicked demon indeed;
Lingering to feed on your collapse.
My dear, choose the wiser way,
Let peace and harmony make way,
Let a smile in tough times,
Let the anger famish.
That’s when you win it over;
Then you shine in the brilliance,
More dazzling than the demon can bear.
I Hold No Regrets
“I hold no regrets” – a displaced soul
I hold no regrets honey,
I hold memories,
I hold you tight and sunny,
I visit cemeteries.
And no tears do I shed,
No remorse is felt,
For our moments aren’t dead.
I’ve relived. I’ve dwelt.
No regrets, but yes… a few wishes.
Wish I’d hugged you tighter..
Planted more kisses…
Could things have been brighter?
Oh and I wish my goodbye wasn’t hurtful,
And my stay longer,
Your tears less desertful,
If only I was stronger.
I hold no regrets honey,
I hold memories,
But indeed I hold wishes,
Heavy as treasuries.
Strangers
Two strangers, stood at a station,
Felt themselves sinking into an awkward situation,
Eyes met for a second or two,
And then looked away as if they had no clue,
Both kept tapping their feet, and had to wait,
Time would not go faster, their train was late,
In slow-motion, the breeze blew their hair,
Oh, the silence, they could not bear,
An hour passed… again…
But it was important, because this is when,
A bullet was shot in the air,
People panicked- unaware-
The strangers cried out loudly and screamed,
ears turned deaf. Black, everything seemed.
And in that darkness, they sank. Collapsed.
Too suddenly, their life lapsed.
Blacked-out, next to each other, they lay.
Now no longer strangers are they,
And now, perhaps their train is too late…
For evermore, on that station… they wait,
And once again, two strangers, stood at a station,
No longer feeling themselves sinking into an awkward situation,
