Today we are talking about the planet, galaxy and how big is our universe.
This is Earth You live somewhere in this massive looking planet And everything you have ever interacted with in your life stays here But this huge planet Is how big as compared to the vast scale of the Universe? For comparison sake, we take Moon. So the moon looks very close to us because this is the only space object that we see so close to us during the night. But, the moon is not actually that close from us Moon is actually this far away from us. Between this distance, easily 30 Earths could fit! And if somehow we were able to travel moon in a car at 100 Km/hr speed Then it’ll take us 160 days! Once we reach the moon,
Earth will look somewhat like this from there. So Earth surely looks pretty huge, right? Now let’s see how does this same blue planet look from Mars So this is a picture taken on Mars by space probe This small dot, is our Earth! And it looks like this from the Martian surface.
Mars’s average distance from Earth is 225 Million kilometers from Earth And it can even reach 425 million kilometers So this means if we have to go, Mars, one day So we’ll have to travel 986 times more than the distance to moon Even a ray of light will take up to 20 minutes to reach till here which means instant communication will not be possible between the two planets.
If we travel a little farther Then we can find the Voyager 1 Space probe which is the farthest flying man-made spacecraft ever It’s the distance from our Earth is 138 (AU) Astronomical Units Where 1 AU is the distance between Earth and the Sun In its travel,
Voyager 1 turned it’s camera back and snapped this picture This doesn’t look like much at first But this is one of the greatest achievements in the human history This Pale bluish dot is our Earth This is our home billions of people have born here and have lived their complete lives here Everyone has seen both happiness and sadness here Only here every religion and every religion creator has taken birth Every king, every pauper, every saint,
every sinner has lived their lives in the entire human history And this, from here, in sun’s white light Looks so tiny Voyager 1 is traveling at 17 km/hr speed In this speed also it won’t be able to escape our Solar System for the next 30,000 years!
Once we leave the Solar System Then we reach the Interstellar neighborhood Means these are our Solar System’s neighbors Here we drop measuring distance in AU’s And use Light Years to measure distance 1 light-year means distance that a ray of light can travel in 1 year which is 9.461 trillion km/hr. Excluding the Sun, our nearest neighbor star, that we call Proxima Centauri is still 4.24 light-years far from us If voyager 1 was to start moving towards it, then it would take it 70,000 years to reach there! If we zoom out a little more, then we can see the entire Milky Way galaxy!
Within this is our Earth, this yellow dot is the range of our radio broadcast signal which means if any alien life is outside this range then they would never know about us human’s existence Our entire galaxy is 1 lakh light years large from one side to the other Here we have approximately 10,000 crore stars and 10,000 crore planets. But you will never be able to see them all at night Because 99 percent stars that you can see at night, is within this tiny square area But this massive galaxy, Still is nothing as compared to that of which it itself is a part of!
After zooming out we can see, what is called a local group of Galaxies This is that part of the space which is a collection of 54 different galaxies That are spread across 1 crore light-years But zooming out even further, we can see the Virgo Super-cluster Of which local group is a tiny part Here distance across one end to another is 11 crore light years! But even this massive Super-cluster, is still a grain of sand as compared to the big Laniakea Super-cluster Which is home to 1 lakh other Galaxies like our Here distance from one end to another Is mesmerizing 52 crore light years!
But, even if we could zoom out more from here till the entire observable Universe, Then we can see that even the Laniakea Super-cluster is just a tiny part of the Universe that we are able to see till now This is the observable Universe! And it has everything inside that till now we have ever been able to see Here we at least 2 lakh crore galaxies,
And in all these galaxies combined, we have so many stars that are even more than grains of sand on Earth! The distance till any end from our observable universe is 4,065 crore light years! Which means the total length of this observable Universe is 9,300 crore light years! But more interesting than this is that beyond this visible sphere of the Universe lies what?
Keep in mind that observable is all that we are able to see as of now, with the help of advanced Telescopes. And this is very possible that the universe beyond this is much larger and much more interesting. We cannot even think about it what all can be out there Because, from that far distance, light could never reach us till now! And maybe, it would never reach us,
because our Universe is expanding at a speed faster than light So the meaning of this is clear, That even if humans lived here for crores of years more but still, in the Universe there would be many such places that would always be hidden from us no matter how much we try to discover them. According to the calculations of the Cosmic Inflation theory, The Whole Universe could be 150 Sixtilion times larger than the observable Universe. This number looks something like this Look at this number closely,
It has so many zeroes that you’ll be amazed For the sake of comparison, If you can think the Observable Universe as the size of a football, then the Whole Universe would be as massive as our Earth in front of it! Just think about it, that we are living inside a football and we have no clue that our Universe is so massive. But we don’t need to feel nervous learning this, on the contrary, we need to think that in this magnificent Universe We have so much to discover ahead..!