We are looking at the past

“It is strange that only extraordinary men make discoveries, which later appears so easy and simple.”

George C. Lichtenberg

Image from NASA

Here on earth, it seems we are very fast and going towards the future. But in the reality we are slow and not much advanced as we think. From the early times till now we have a big screen to watch which is free of cost and have an average resolution as 570 megapixels. Without any suspense that huge screen is the night sky. Its resolution is actually infinity but our eyes are limited to 570 megapixels.

We have such advanced technology (like HUBBLE SPACE TELESCOPE) to observe space but still, we can only see the past and not even the present. For some people, it may be quite odd to get but in science, we can only tell the truth.

To understand this you don’t need any advanced math or physics you only need some very basic maths like multiplication, division, subtraction, addition, and some sense to think.

We actually need to know about a few fundamental concepts before we proceed into the main topic.

Speed of light

Speed of light is one of the fundamental constants in physics. Many times it acts as a limit to many situations. It is commonly denoted as C. its value is 299792458 meters per second (~300000000 meters per second) in a vacuum. This value can’t be more but can be less in mediums like diamond, glass, water, etc. As we are mostly dealing with vacuum there is no problem.

Velocity

It is nothing but the speed of a particle specified along with the direction. We only need its mathematical form to do our calculations.

VELOCITY = DISTANCE/TIME ( In reality it is DISPLACEMENT/TIME)

By modifying it for our requirement we have

TIME= DISTANCE/ VELOCITY

Modeling

Now let us do some mathematical modeling for our reasoning.

So from the table above we can infer something very interesting but tricky. LET’S DO IT.

> Sun is a star. It is missive and produces light due to the chemical reactions of a complicated network of gases. It is just to give a comparison.

> Pluto is a distinct object in our solar system. Imagine that a movie (like Avengers endgame) is playing there is a very big screen so that you can watch it with the help of a normal telescope-like CelestronAstroMaster 130 EQ (roughly cost 25000₹). The movie will get over by 3 hours In Pluto but on earth, it will be visible after 6 months. So if you are watching a movie like that now, in reality, the movie was played in Pluto 6 months before. ISN’T IT AMAZING? So in simple words, you are observing the past in your present.

> So ALPHA CENTAURI A is a star that is closest to earth other than the sun. But if you are observing it using the Hubble telescope then we are watching the happenings that took place almost 4200 years ago in that star at that period in the earth we were constructing the great pyramid of Giza. Again it is evident that we are watching the past.

Creator: Diego Fiore Credit: Getty Images/iStockphoto

Summery

The farther away an object is, the longer its light takes to reach us. When you look across the room, you see something as it was a few billionths of a second ago, and when you look at the moon, you see the light that left it a little more than 1 second ago. If our star, the Sun, were to suddenly burn out, we wouldn't even know it for more than 8 minutes, because the last bit of light that left it would take that long to travel to Earth! Don't worry, though. The Sun is going to last for another 5 billion years or so! But what about all the distant stars? It takes much longer for their light to reach us. When you look at the stars at night, you are seeing light that may have taken 20 or 30 or even a few hundred years to reach your eyes. You are looking back in time. The distances in the universe are so vast that scientists use the term "light year" to measure them (A light-year is the distance light travels in one year, or 10 trillion kilometers. That's 10000000000000 km!).

VINCENT VAN GOGH: STARRY NIGHT from vangoghgallery

REFERENCE AND INSPIRATIONS

§ spaceplace.nasa.gov(Hubble telescope).

§ MIT OCW Classical mechanics(2018) [Inspiration].

§ Berkeley physics course volume 1 by C.Kittel [Inspiration].

§ Where are stars – NATIONAL GEOGRAPHIC You Tube.

John Paul's writings

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