When you see the Facebook or Google memories you are looking at a piece of your past! Every snap and every video would become a part of your past which is frozen in time!
But you do not need these apps to see the past!
You can literally look up the sky in the day or the night to see the past!
Apart from the sky; whatever you see in the sky is the past! Like like a delay telecast; you are seeing what was the sky some time back!
Even the moon you see so clearly is how it was some seconds back and not how it is right now! Of course when I am writing this blog, it is day and I cannot see the moon at all! But even the sun which I see is how it was some minutes back! If the sun is gone; I have around 8 minutes to act till I realize that it is no longer there!
Every time you look at the night sky, you are seeing the past!
This is because it takes time for the light from distant celestial objects to travel across space and reach your eyes. The farther away an object is, the longer its light takes to reach Earth, so the further back in time you are observing.
Everything of course depends on the speed of the light!
Light, which travels at a constant, finite speed of about 300,000 kilometers (186,000 miles) per second, is the fastest thing in the universe for now! Though apparently your mind and thoughts are faster than the light but lets not digress!
Now even though light is fast; the distances between celestial objects are so vast that light can take years, centuries, or even millennia to complete its journey to Earth!
So the sky you see is a Google memory of the past! How far or back into the past you see depends on the object you are observing!
So our closest celestial friend, the Moon with an average distance of about 384,400 km, its light takes just over 1.3 seconds to reach us. So, you are seeing the Moon as it was a little over a second ago!
Then we have our dear Sun which is about 150 million km away, so its light takes approximately 8.3 minutes to travel to Earth. When you look at the Sun (with proper protection), you see it as it was 8.3 minutes in the past! So when you say it is a sunny day, the correct statement is that it was sunny 8 minutes back!
Then you have the nearest star!
The closest star system to our own, Proxima Centauri, is 4.24 light-years away. This means its light takes 4.24 years to reach Earth, and you see it as it appeared 4.24 years ago! How cool is that!
Still cooler is if you have access to the powerful telescopes like the Hubble and James Webb Space Telescopes! If you do please allow me to see!
For now just know that astronomers can capture light from galaxies that are billions of light-years away. This allows them to see the universe as it was when it was still very young!
This time delay is very cool since you can study the past!
In fact even the light from a “dead” star takes so long to get here, so it’s possible that a star you see in the sky has already died!
The “light” of its death—a supernova—would not reach us until the appropriate number of years later!
What is thus seen is the cosmic time machine and by studying objects at different distances, astronomers can piece together the history of the universe. The farther they look, the further back in time they see, allowing them to witness the evolution of galaxies and the universe itself!
Then you can see some system with life and say Koi mil Gaya! Which reminds me of Rakesh Roshan!
Now look into the past and sleep!
Shub ratri!
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