We all know that the earth is spinning. Not only does it spin on its own axis of rotation, but it also orbits the sun as it spins.
The moon spins as it orbits the earth. And even the sun spins at the center of our solar system.
In fact, every planet, moon, asteroid, star, and galaxy is spinning right now.
So what makes the entire UNIVERSE spin!?
In this article, we look at the laws of physics which can explain this dizzying reality.
But be warned… the facts might make your head spin a little too!
The most important force in the universe is gravity. It holds us together and keeps us from flying apart.
If you were to jump off a cliff or fall into a black hole, you would feel intense gravitational forces pull towards the object.
You wouldn’t fly away because the force of gravity is much stronger than any other force in nature.
Even light cannot escape the grip of gravity.
This means that if something has mass (like a rock) then it will always attract anything with mass (like another rock).
This is why objects like planets, moons, asteroids, stars, and galaxies orbit each other.
They have mass, and so they are attracted to each other.
And since everything in the universe is made up of particles called atoms, these same forces work between them too.
This is why the Earth revolves around the Sun. Because the Sun has more mass than the Earth, it attracts the Earth.
And since the Earth has more mass than the Moon, it attracts the Moon. And so on and so forth.
Another important force in the universe that works against gravity is inertia.
This force causes things to continue moving in their current direction unless acted upon by some external force.
For example, when you throw a ball upwards, it continues rising until it hits the ceiling.
Or when you push down on a heavy book, it doesn’t stop falling until it reaches the floor.
But inertia isn’t just limited to physical objects. Electrons, quarks and neutrinos all obey the law of inertia.
That means that they move in a straight line unless acted upon by some outside force.
So, in a cosmological model, once gravity gets particles spinning, inertia (from angular momentum) keeps them spinning in the same direction unless otherwise interrupted.
This creates a constant flow of energy throughout the cosmos.
Did The Big Bang Make Everything Spin?
The universe was born in a big bang explosion. When the universe first began expanding, it was very dense and hot.
It had lots of energy and momentum. And this caused the expansion to speed up.
As the universe expanded, the temperature dropped, and the density decreased.
Eventually, the universe cooled enough for matter to form. Atoms formed out of the primordial soup of subatomic particles.
And over billions of years, those atoms came together to create gasses of varying densities.
The atoms formed clumps of matter, and the clumps of matter collided to form larger bits of matter.
Eventually, they spun together to great stars, planets, comets, and asteroids.
On the largest scales, they created spinning solar systems and spiral galaxies.
Why Does Our Solar System Spin?
Our solar system was created around four and a half billion years ago when a sprawling cloud of helium and hydrogen gasses began to interact and compress together.
Scientists believe that a supernova event may have been the catalyst for this interaction.
Due to inertia and angular momentum, the gasses continued to compress and rotate into a concentration of matter that formed planets, moons, and the sun.
The asymmetry between matter in the cloud caused the matter to spread into a flat disc-like shape – almost like pizza dough being spun in a restaurant.
This shape can be seen repeatedly throughout the observable universe.
Just think of the way water spins down a plug-hole, or hurricanes spin as they rip through the landscape.
The laws of angular momentum mean that spinning particles eventually form a wide opening and a narrow center.
Does Everything Spin In The Same Direction?
Due to the laws of angular momentum, everything in a single system rotates in the same direction.
In the case of our solar system, the preferred direction is counter-clockwise. However, there are some notable exceptions.
Venus is the only planet in our solar system that actually rotates clockwise.
Scientists believe that a collision with a foreign body caused the planet to flip on its axis and rotate in the opposite direction to everything around it.
Uranus is also at odds with the rest of the solar system.
Scientists believe it was bumped on its side by a high-impact collision, and now it rotates differently from its neighboring planets.
Relative to the milky way, there doesn’t seem to be any preferred direction that galaxies tend to spin in.
Some spin clockwise, others counterclockwise. However, spiral galaxies do seem to
How Fast Are We Spinning?
The earth rotates every 23 hours, 56 mins, and 4.09054 seconds, and its circumference measures approximately 40,076 kilometers.
This means that at the equator, the surface of the Earth moves at a speed of 460 meters per second! That’s 1,000 mph!
Luckily, thanks to gravity, we cannot detect a thing.
That is just the speed at which we rotate on our own axis. What about the speed at which we are orbiting the sun?
Well, the earth covers this route at a speed of almost 30 kilometers per second, which is the equivalent of 67,000 miles per hour! Dizzy yet?
Hang onto your hats, because in addition to all that spinning, the solar system, with us included in it, is whirling around the center of the milky way at around 220 kilometers per second.
That’s 490,000 miles per hour!
As The distances get greater, the speed of spinning increases. Just imagine linking arms over the shoulder in line with some friends and turning in a circle.
The person in the middle of the line will rotate the slowest, whereas those on the two ends of the line will be moving very fast.
As more people join each end of the line, the outermost speed becomes quicker. Eventually, some two people will be running like crazy!
What About Black Holes?
Black holes are spinning too! They spin because they contain so much mass that their gravitational pull causes other things to orbit them.
This makes black holes act like giant gyroscopes. As time goes on, these gyroscopes slowly slow down until they stop altogether.
But what happens if you get close enough to a black hole? You’ll fall straight in.
If you do manage to survive the trip, you’ll find yourself in an environment where gravity is so strong that nothing can escape.
Even light will be pulled back towards the black hole. So if you ever visit a black hole, you might want to wear your spacesuit.
The reason that everything in the universe is spinning is that the forces of gravity and inertia affect the atoms and particles that make up everything.
Without the force of gravity, atoms would fly off into the sky and never come back.
But because of the force of gravity, the atoms stay together and form objects such as stars, planets, and even ourselves.
So next time you look out at the night sky, take a moment to think about how amazing it really is.
And next time you stand still, remember that you are not really still at all but are in fact flying through space at speeds you cannot even comprehend!
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