Light year which is usually also written as ly. Light travels a Distance of three hundred thousand kilometers in one second. There are eighty six thousand four hundred and 86400 seconds in one day. Twenty five billion ninety two million light in one day. Kilometers travel. When we multiply twenty-five billion ninety-two crores by three hundred and sixty-five 365 days of the year, the answer will be ninety four billion kilometers. The distance that light travels in one year is called a light year.

I am currently sitting near the computer table. If I measure the distance between me and the computer table with a scale of centimeters cm or millimeters mm, then this is understandable. But if I If I start measuring the long distance of 9000 nine thousand kilometers from Moscow (city in Russia) to Johannesburg (city in Africa) with very small scales (centimeters or millimeters), then it will be a mind- and soul-stirring task.

As long as we measure distances inside our solar system, kilometers and miles are sufficient for these measurements, but when we want to measure interstellar distances outside our solar system, these distances are much larger. And there will be long distances where the scale of kilometers or miles will feel just like measuring the route from Russia to Africa in centimeters or millimeters.

For example, after our Sun, the closest star to our Earth is Alpha Centauri. It is 4.25 light-years away from us. km/h sixty thousand kilometers per hour. That spaceship will run at the same speed for 76000 seventy-six thousand years without any break, then this spaceship will reach our neighboring star Alpha Centauri.

(Remember that the Voyager 1 spacecraft is heading towards our neighboring star at the same speed. It has been more or less four decades since it left Earth, and in those forty-two years it has traveled more than 21 billion kilometers away from us. Is)

Light travels 300,000 km in one second, which is about sixty billion miles in a year. We can say that the neighboring star of our Sun, Alpha Centauri, is about two hundred and fifty-five 255 from us. It is a thousand kilometers away.

Why is this unit or scale called light year?

Actually, whatever we see in the night sky, be it stars or planets, galaxies, nebulae, we can actually see them because of the light coming from them.

For example, I have been looking at the Andromeda Galaxy (5.2 million light-years away) through my binoculars in 2018. This means that every time I look at Andromeda, I am actually 5.2 million light years away. Looking back over the years.

This is more easily understood.

The most likely assumption is that you are reading this article on your Mobile Screen. Now there will be a distance of about eight to ten inches between your mobile screen and your eyes. Now if I say this. That you are looking at the past while looking at the mobile, then my point will not be wrong.

how does?

Why are you seeing the mobile screen?

The answer to this question would be "because he is bright".

What happened was that the light waves came out from the mobile screen and hit your eye while traveling, the natural sensors in the eye and the sophisticated system made an image of this light and showed you the text that you are reading, but these eight A distance of ten inches is so small in terms of the speed of light that it would be very difficult to calculate the time spent on it. Light travels such a long distance in one second that eight of ten inches of that distance The time taken will be very short. But it is certain that you are looking at the past while staring at your mobile screen. Similarly, we are seeing every astronomical body in the sky in its past state. Keep in mind that light is the fastest moving object in our universe (so far investigated).

How vast is the universe?

Be aware that the closest star to us after the Sun is Alpha Centauri, which is 4.25 light-years away. But modern man-made telescopes can see much further. Galaxies that have been discovered by modern telescopes are located at distances of 14 billion light years (14 billion ly) from us.

That is, if we want to go to the most distant galaxies and we have a vehicle that has a speed of 300,000 kilometers per second, it will take us more or less fourteen billion years to reach the last visible galaxies. This universe, its views and its distances keep us immersed in the sea of ​​surprises every moment. If you ever get time, you must consider what this universe wants to say to us in which we are living. ? Whenever I have meditated on this universe, I have heard the same whispers coming from the distant corners of this universe that "this curious universe was created to be contemplated".