As best stated by Einstein, “If you can’t explain it to a 6-year-old, you don’t understand it yourself”. In this article we will go over everything you will need to know to explain black holes to kids of all ages.
Table of Contents
- 1 Gravity
- 2 What Are Black Holes?
- 3 What Are Black Holes Made Of?
- 4 Just How Heavy Are Black Holes?
- 5 How Big are Black Holes?
- 6 Where Do Black Holes Come From?
- 7 Will Our Sun Become a Black Hole?
- 8 How Many Black Holes Are There?
- 9 Can We See Black Holes?
- 10 Can Black Holes Die?
- 11 What Happens if We Fall into a Black Hole?
- 12 References
Gravity
Gravity is one of the fundamental forces in our Universe. It is what keeps us on the Earth, what keeps the Earth in our solar system, and what keeps our solar system in our galaxy. Any object that has mass has gravity, you, me, your pets, planets, stars, everything! The strength of the gravitational pull that an object has, depends on how heavy it is.
For example, the Earth is very heavy, so it has a stronger gravitational pull than you and me. While the Earth’s gravitational pull is strong, we can still escape it. We can jump off the ground and escape its pull for a few moments, we can launch a plane into the air, and we have even launched rocket ships off Earth entirely.
The lighter something is, the easier it can escape a gravitational pull. Imagine trying to throw a tennis ball into the air verse a bowling ball. Both are possible, but the tennis ball will take much less effort to throw, this is because it weighs less and therefore the Earth’s gravity has less of an affect on the tennis ball than the bowling ball.
The lightest thing in our Universe is light. Light from stars, the Sun, light bulbs, all travel in the form of tiny little particles called photons. Photons have zero weight. This makes it easy for them to escape from almost any gravitational pull. Except one, the gravitational pull from a black hole.
What Are Black Holes?
A black hole is an object in space that is so heavy and has so much gravity that not even light can escape its grasp. This is how a black hole gets its name, with no light escaping it just looks black. Our eyes see an object when the light from that object reaches our eyes. If no light can reach our eyes thing it just looks black.
What Are Black Holes Made Of?
Everything in the Universe is made up of tiny particles called matter. A black hole has so many particles so close together it is very heavy. Think of a tennis ball and a baseball, they are about the same size, but the baseball weighs more than the tennis ball. This is because the baseball has more matter particles than the tennis ball. Black holes have the most amount of matter smooshed into the smallest spaces in our Universe.
Just How Heavy Are Black Holes?
Black holes are put into four groups based on how much they weigh, miniature black holes, stellar black holes, intermediate black holes, and supermassive black holes. Miniature black holes weigh less than 3 times the weight of our Sun, whereas supermassive black holes weigh millions to billions of times the weight of our Sun. Astronomers believe there is a supermassive black hole in the center of our galaxy. Other smaller black holes can be found any where in a galaxy.
How Big are Black Holes?
A stellar black hole will weigh about 20 times as much as our Sun but is only about 10 miles wide. Our Sun is 865,370 miles wide. How can something that is smaller than our Sun, weigh so much more than our Sun? Remember matter? That is why. A black hole has more matter crammed together into a smaller area. The supermassive black hole at the center of our Milky Way galaxy weighs 4.3 million times the weight of our Sun and is 14.6 million miles wide. Below is an example of just how big black holes can be.
Where Do Black Holes Come From?
To first understand where black holes come from, we need to understand what a star is. A star is basically a giant ball of gas and fire. Our Sun is a star. It looks different than the stars you see in the night sky because we are so close to our Sun. Stars live very long lives but eventually, they do die and stop making light. Some stars explode when they die. Other stars are so heavy that they implode or collapse in on themselves. This is how black holes form. When the heavy star collapses in on itself it squishes all its matter into a very small space. This is the black hole.
Will Our Sun Become a Black Hole?
No, our Sun is not heavy enough to collapse in on itself. If you remember from above, we said the smallest black holes are still three times the weight of our Sun.
How Many Black Holes Are There?
There are billions of black holes in our Universe! Too many to count. Astronomers predict that there is a supermassive black hole at the center of every galaxy. The supermassive black hole at the center of our galaxy is called Sagittarius A*.
Can We See Black Holes?
We technically can never see the black hole itself. Light coming from objects and entering our eyes is how we see things, so if a black hole traps all light, we can’t see it. So how do we know its there? Do you remember gravity? Gravity from a heavy enough object affects how the objects around it move.
Since black holes have so much gravity, they can affect the planets and stars around them. Astronomers watch how planets and stars move and interact with each other and with a lot of fancy math, they can determine not only if there is a black hole but also where that black hole is.
Not only does a black hole’s gravity affect the heavy things around it but also the light things around it like gas and dust. Because gas and dust are so light and a black hole’s gravity is so strong, some black holes get the nearby gas and dust to spin so fast around it they heat up and glow. This is what we see, an orange glowing mass with a black hole in the middle. Most of the photos of black holes that you see, are actually artist conceptions of what we think they look like, such as the one below.
This is not a real picture of a black hole; this is what the artist and scientists at NASA and JPL think a very powerful black hole could look like. The world’s first real picture of a black hole was captured by the Event Horizon Telescope in 2019. This image is of the supermassive black hole at the center of our own Milky Way galaxy, seen below.
This picture seems pretty boring compared to the artist conception. This is because black holes are very far away from us, and our telescopes are not yet powerful enough to get a clear image of a black hole.
Can Black Holes Die?
Yes, eventually black holes can die if they run of out fuel to feed it. Black holes grow and eat the gas, stars, and dust nearby. If it runs out of things to eat, they will begin to shrink until they just pop away in a flash of energy. But this would take a very long time, about 10^100 years. That’s 10 times 10, one hundred times.
What Happens if We Fall into a Black Hole?
If you choose to jump into a black hole, you will undergo what is called spaghettification. The black hole’s gravity is so strong it would pull you until you looked like a long spaghetti noodle!
Black holes are still a huge mystery to astronomers, but now that we know how to find them, we can study them. Understanding where the first black holes came from, and how a black hole interacts with the galaxy it is in, will tell astronomers a lot about the Universe as a whole and how it changes over time. Maybe one day you will build a spaceship and be the first person to get close to a black hole, just not too close!
References
https://www.npr.org/2013/12/27/256897343/stretch-or-splat-how-a-black-hole-kills-you-matters-a-lot
https://www.discovery.com/space/the-death-of-black-holes
https://images.nasa.gov/details-PIA22085
https://eventhorizontelescope.org/blog/astronomers-reveal-first-image-black-hole-heart-our-galaxy
https://curiosmos.com/this-fascinating-video-shows-the-incredible-scale-of-black-holes/
https://www.space.com/17001-how-big-is-the-sun-size-of-the-sun.html
https://www.esa.int/kids/en/learn/Our_Universe/Story_of_the_Universe/Black_Holes
