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Tell Me Why #8: Why is the Earth, Sun, Moon and all planets round in shape?

Team StoryWeavers|May 25, 2022, 08:28 IST| 68

Welcome to BYJU’S ‘Tell Me Why’ where we explain to you the ‘why’ behind anything and everything that’s been on your mind! So go ahead and ask us a question that starts with ‘Tell Me Why’. We’ll pick the most intriguing questions and feature them along with an illustrated answer on our blog.

To ask your question, fill up the form here:

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Today we are answering a very interesting question asked by class 10 student Vivek Kumar, from Hyderabad. He wants to know:

Why are the Earth and other planets round?

Wait, what? The Earth is actually flat, haven’t you heard?

Kidding! We’ve actually known that the Earth is round for at least 2,000 years. In fact, the vast majority of objects in our solar system are spherical, from the Sun to planets to moons.

But before we answer that question, we must actually ask ourselves how do we know for sure that our home is a globe and not a flat flying disk. 

How do we know the Earth isn’t flat? Prove it!

Fair enough! As students of science, we must not accept any truth without asking for proof.

The most optimal way to determine whether our planet is a thick disk or a huge sphere is to view it from a more distant perspective. One such picture would be enough to falsify one hundred claims about the Earth being not a globe. 

Satellites and astronauts have provided us with many pictures of Earth’s blue curvaceous body, but apparently, these pictures are not enough. Those who believe that the Earth is flat could claim that they all are fake pictures. The technology to make such realistic fake images does exist and can be quite easily afforded by multi-billion-dollar government-funded organizations like NASA. So, fair enough. 

Simple yet undeniable evidence that proves a curved Earth was gathered more than 2,000 years ago. Around 250 B.C., a few Greeks realized it with just two sticks. They fixed two sticks on the Earth’s surface 500 miles apart from each other in two different cities. 

If the Earth was flat, the Greeks would have observed that both sticks cast no shadow when the Sun was directly above them. However, what they observed was that the stick located 500 miles towards the north did cast a shadow while the other one did not!

It’s a no-brainer that this is possible if and only if the Earth’s surface is curved such that the other stick is “inclined”.

 Two sticks, that’s all it takes!

Here is another proof. Greek philosopher Aristotle observed that the shadow Earth casts on the moon during a lunar eclipse is shaped like an arc. It is then Clark-Kent-is-Superman kind of obvious that such a shape can only be witnessed when the illuminated object is curved, more precisely, a sphere. 

If the Earth is really round, why can’t we see it?

This is a reasonable question to ask: if the earth is round, why don’t I “feel” or “see” this curvature. The surface does appear flat when viewed from the top.

Actually, people can’t “see” the curvature because they simply haven’t climbed high enough.  For a six-foot-tall person, the curvature is approximately 3 miles away. Studies place the threshold altitude for seeing Earth’s curvature at about 35,000 feet. Even at this height, it is difficult to discern the curve as the observer requires a wide angleview.

That’s the same reason why it is impossible to see the curvature of the Earth even from an aeroplane that flies up to 28,000 feet above sea level.

If you really want to see the curvature of the Earth, you just have to climb up high enough. Or take a trip to space  like Jeff Bezos did! 

Now that we know the answer to how do we know that the Earth is a sphere, we must ask the ‘why’ question.

Why are Earth and all the planets spherical in shape?

Seriously, why are planets spherical? Why don’t we live on a cylindrical or cube-shaped planet?

The main culprit is gravity. Gravity is a force, which means that it pulls on things. But the Earth isn’t the only thing which has gravity. In fact, everything in the universe, big or little, has its own pull because of gravity – even you. 

Why does everything have gravity? Because everything has mass. Mass is a measure of how much material there is in anything. It could be in the form of rocks, water, metal, gases, people – anything.. 

Isaac Newton was one of the first scientists to figure out the rules of how gravity behaves. And one important rule of gravity is that it always pulls toward the center of mass.

The Earth and all planets are round because when the planets formed, they were composed of molten material – essentially very hot liquid. Since gravity always points toward the center of a mass, it squeezed the stuff the Earth is made of equally in all directions and formed a ball. When the Earth cooled down and became a solid, it was a round ball.

And voila! We have our round abode! What if Earth stops rotating all of a sudden? What would that lead to?

We hope we have answered all the questions. And thank heavens that the planets are spheres! If they were tetrahedrons or toruses or pentagonal prisms, it would be much trickier to make a solar system model.

Read more Tell Me Why stories like these here!

Tell Me Why There Are Silent Letters in English Language?

Tell Me Why Fire is Hot?

Tell Me Why Do We Have Unique Fingerprints?

About the Author


Raza has been writing since 2008, be it fiction, poetry, or articles on science, politics, and history. He believes that words can change the world, and he uses them to inspire and empower people through his writing. When he is not working, he is watching nature documentaries or playing with his cats.

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Comments



hanook

April 6, 2022

Is there any gravity in the centre of the earth, if so on which direction it pulls


Aditi Sulgudle

April 8, 2022

Thanks 😊


C.Pooja

April 8, 2022

A planet’s gravity pulls equally from all sides. Gravity pulls from the center to the edges like the spokes of a bicycle wheel. This makes the over all shape of a planet a sphere,which is a three-dimensional circle


Priyanshi

April 8, 2022

Because of there gravity.


Kavya Kashyap

April 8, 2022

All the planet round because they are gravity are equal of all sides


Ashish Mane

April 8, 2022

👍👍


Rajalaxmi dakua

April 8, 2022

Science


Manas Nair

April 8, 2022

Gee! Never knew this as well as it has been explained in this article.
Thanks BYJU’S! really is informative. Keep it up!


Avantikaa Das

April 8, 2022

Ummmmmm…….
I have been always wondering why every planet,star,and also the moon is round………………
Yay!!!!!!!!
I’m very happy that I got the answer
Thank you so much for the answer^_^^_^^_^^_^^_^^_^^_^^_^^_^^_^^_^(◍•ᴗ•◍)❤(◍•ᴗ•◍)❤(◍•ᴗ•◍)❤(◍•ᴗ•◍)❤(◍•ᴗ•◍)❤


Ansh Sharma

April 8, 2022

😊ℹ️ Cool 😎


Hargun Singh

April 8, 2022

Earth is round because of gravity.


Priyal Patel

April 8, 2022

A planet is round because of gravity. A planet’s gravity pulls equally from all sides.


Rishab Jitendra Sharma.

April 8, 2022

Because earth have gravity


Om kadahatti

April 8, 2022

Why is it’s round


Ankit Kumar Pradhan

April 8, 2022

A planet’s gravity pulls equally from all sides. Gravity pulls from the center to the edges like the spokes of a bicycle wheel. This makes the overall shape of a planet a sphere, which is a three-dimensional circle


Prachi Vilas pimpale

April 8, 2022

Tell me why water ,air and all other components that is needed for the survival of animals is on the earth and why not on the other planets.


Priyanshi saini

April 8, 2022

A planet is round because of gravity


SAYALI

April 8, 2022

All planets are round because they need to revolve around the sun. And if planets are square, rectangle, and triangle then we cannot drive boats in oceans


Anand

April 8, 2022

Because all planets made by rock and other particles also gases and because of gravity when Earth is made it get a shape called circle and also all planets get circle shape beacuse of gravity


Shreya

April 8, 2022

Respected sir/mam,
These are my Tell Me Why questions👉🏻
1) Why there is no gravity in space?
2) Where does the sun goes in the night?
Please answer me.

Thank you


Kashish Fatima

April 8, 2022

The gravitational force of planet’s mass pulls all of its material toward the centre, smoothing out any jarring non-roundness.


Nargis Shahin

April 8, 2022

Just like our universe is there many universe.


Sneha Gautam

April 8, 2022

A planet is round because of gravity,A planet gravity pulls equally from all sides gravity pulls from the center to the edge like the spokes of a bicycle wheel this makes the overall shape of a planet a sphere, which is three-dimensional circle


Abhishek Gupta

April 8, 2022

Due to the Force of Sun’s Gravitational Force.


Toufiq

April 8, 2022

Because of gravity


Smital

April 8, 2022

Clouds are just water vapour, so why do they move?


Avya Singh

April 8, 2022

1.) The planet is round because of gravity


Chirag jha

April 8, 2022

Most beautiful words you use in it


Yogita

April 8, 2022

The answer is the gravity allows the planet to be sperical


Vijay KUMAR

April 8, 2022

I like byju’s


Sushil kumhar

April 8, 2022

Ans: the gravitational force of a plants pulls mass and some materials of plants.


Raj Kumar Gupta

April 8, 2022

This is amazing about the earth . thank you for this information 💙👍


Joyshree Das

April 8, 2022

I can understand very easily


Aryan Sinha

April 8, 2022

Due to gravity and force


Dhatrisree

April 8, 2022

Is there a chance for the Multiverse to exist?


Gunin

April 8, 2022

The gravitational force of the planets mass pulls all of its material towards the center smoothing out any jarring non roundness


Arpita Das

April 8, 2022

Nice…..😘😘


Bhavya Dashrath Panchal

April 8, 2022

1.Why the temperature of inner core of earth is very high like sun?
2.Why Jupiter and saturn are made from gases?
3.Why do humans are very intelligent and capable of doing such great things but other animals can’t?!
Pls give me the answer


B.Lakshmipathy.

April 8, 2022

Because of Gravity of the Earth and other planets.


Tejas Burkul

April 8, 2022

a planet is a round because of gravity. A planet gravity pulls equal from all side gravity pull from the center to the ages like the spoke of bicycle wheel this makes the overall shape of a planet a sphere which is a three dimensional circle


Tanishq s daharwal

April 8, 2022

What is atmosphere


Shoaib Mohammadali sayyad

April 8, 2022

The Sun and all eight planets of the solar system are round. Why? The gravitational force of a planet’s mass pulls all of its material toward the center, smoothing out any jarring non-roundness. Many of the smaller bodies of the solar system are not round because their gravity is not enough to smooth out their shape.


Vidya Reddy

April 8, 2022

Why is the land flat ?


Khushi

April 8, 2022

Earth planet’s gravity pulls equally from all sides


Maanav

April 8, 2022

Nice👌👌👌👌👍👍👍👍👍


Krishna gupta

April 8, 2022

Because earth has gravitational force or due to magnet force always rational north to south movement that s way sphere.


Sagnik Chowdhury

April 9, 2022

Today I came to know that all planets are round due to presence of gravity in them.


Anishka Mohanty

April 9, 2022

The earth is round . The proof is if you start walking from a point and keep on walking you will reach on the same point


mounish.R

April 9, 2022

The gravitational force of a planet’s mass pulls all of its material toward the center, smoothing out any jarring non-roundness. Many of the smaller bodies of the solar system are not round because their gravity is not enough to smooth out their shape.


Sneha Khan

April 9, 2022

•The force of gravity from all sides of the earth may cause the round shape.
• but the earth is not totally round it’s really looks samne as orange ( fruit) figure


Daksh Deepak Swami

April 9, 2022

Planet is round because gravity of planets gravity pull equally from all sides gravity pull from the centre to the age like the smoke of a bicycle wheels these make the over all shape of a planet a sphere which three dimensional circle


Aaradhya

April 9, 2022

This answer is very useful for me 😊and now I will also tell ‘”Why planets round in shape” to my friends


Mayuri Priti Dayama

April 9, 2022

1.A planet is round because gravity.


Ranodip Paul

April 9, 2022

The earth is round because of the sun’s ultimate gravity.The sun’s gravity makes everything round and if the object is not round , the sun’s gravity starts working and the pressure pressent in gravity makes it round


Vishaya

April 9, 2022

Earth is round because it has infinite states.

Other planets are round because it has infinite space / cities


Amogh Kottada

April 9, 2022

If gravity made the planets round, them why are we not round. Because even we have gravity. And if the size is the answers then what about moons, asteroids and meteroids?


Shafquat Zabin

April 9, 2022

Thankyou byjus for this informative series
I have one question:-
Why Our nails have no blood?


Amey Jangam

April 9, 2022

Planets are round because of gravity.


Ayush Shah

April 9, 2022

Why the moon is cold and looking white from Earth 🌍.


Araminta Ajith

April 9, 2022

The planets are round because of the gravitational pull the gravitational pull that I mean is not the gravitational pull of the Sun which keeps the planet in their orbits or the pull of the earth that keeps all of us on the ground it is none of these it is the pull of each and every planet the gravitational pull of all the planet in the solar system is to the centre of the planet the gravitational pull of the earth is coming from the centre of the earth gravity act as a machine that all keeps us on the ground in gravity is very important for all the first to survive even a disaster could happen if gravity is absent for just 5 seconds gravity all of us to the centre of the earth that does not mean we will be pointed to the centre of the earth It means that gravity acts on us downwards so that if we are in any position gravity will act us even if we are at the bottom of the earth It will act on us


S.m.thamizharasan

April 9, 2022

Good


Ananya Kumari

April 10, 2022

Very interesting 😊


Shaikh Fatima Zikra

April 10, 2022

A planet is round because of gravity. A planet’s gravity pulls equally from all sides. Gravity pulls from the center to the edges like the spokes of a bicycle wheel. This makes the overall shape of a planet a sphere, which is a three-dimensional circle.


Harsh Gupta

April 10, 2022

1.)What is Holographic Universe?
2.)Why we cannot enter in the Black Hole?


Ayush Dekate

April 10, 2022

A planet’s gravity pulls equally from all sides. Gravity pulls from the centre to the edges like the spokes of a bicycle wheels. This makes the overall shape of a planet a sphere, which is a three- dimensional circle.


Aaradhya Pandey

April 11, 2022

I Like this video please send me


ANANTHA bhavaani prasad

April 11, 2022

Kidding! We’ve actually known that the Earth is round for at least 2,000 years. In fact, the vast majority of objects in our solar system are spherical, from the Sun to planets to moons.

But before we answer that question, we must actually ask ourselves how do we know for sure that our home is a globe and not a flat flying disk.

Fair enough! As students of science, we must not accept any truth without asking for proof.

The most optimal way to determine whether our planet is a thick disk or a huge sphere is to view it from a more distant perspective. One such picture would be enough to falsify one hundred claims about the Earth being not a globe.

Satellites and astronauts have provided us with many pictures of Earth’s blue curvaceous body, but apparently, these pictures are not enough. Those who believe that the Earth is flat could claim that they all are fake pictures. The technology to make such realistic fake images does exist and can be quite easily afforded by multi-billion-dollar government-funded organizations like NASA. So, fair enough.

Simple yet undeniable evidence that proves a curved Earth was gathered more than 2,000 years ago. Around 250 B.C., a few Greeks realized it with just two sticks. They fixed two sticks on the Earth’s surface 500 miles apart from each other in two different cities.

If the Earth was flat, the Greeks would have observed that both sticks cast no shadow when the Sun was directly above them. However, what they observed was that the stick located 500 miles towards the north did cast a shadow while the other one did not!

It’s a no-brainer that this is possible if and only if the Earth’s surface is curved such that the other stick is “inclined”.

Two sticks, that’s all it takes!

Here is another proof. Greek philosopher Aristotle observed that the shadow Earth casts on the moon during a lunar eclipse is shaped like an arc. It is then Clark-Kent-is-Sup

This is a reasonable question to ask: if the earth is round, why don’t I “feel” or “see” this curvature. The surface does appear flat when viewed from the top.

Actually, people can’t “see” the curvature because they simply haven’t climbed high enough. For a six-foot-tall person, the curvature is approximately 3 miles away. Studies place the threshold altitude for seeing Earth’s curvature at about 35,000 feet. Even at this height, it is difficult to discern the curve as the observer requires a wide angleview.

That’s the same reason why it is impossible to see the curvature of the Earth even from an aeroplane that flies up to 28,000 feet above sea level.

If you really want to see the curvature of the Earth, you just have to climb up high enough. Or take a trip to space like Jeff Bezos did!

And voila! We have our round abode!

nice to meet you byjus


Sniti

April 12, 2022

Earth is like a sphere bcoz of
Gravitational force of sun .
Moon n earth


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