# So, You Think You Understand Infinity?

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The definition of infinity is concrete, right? Not so much. It's hard enough to contemplate the basic idea of infinity. But when you really start playing with the concept, amazing things happen. For example, did you know that there's more than one kind of infinity, and that some are bigger than others? Check out some of the coolest ideas about infinities and how they work.

#### This Is How To Count To Infinity

Did you know some infinities are bigger than others?

##### How to Count Infinity
MinutePhysics – MinutePhysics

#### How Many Infinities Are There?

More than one.

##### How many kinds of infinity are there?
Vi Hart – Vi Hart

### Key Facts In This Video

1. In math, all a number needs to be infinite is to be bigger than any finite number. 00:09

2. There is no set of surreal numbers because there are too many to fit in this set. 07:38

3. Each unique counting number also has a unique prime factorization. 08:45

#### Infinity Is Bigger Than You Think

It's truly mind-blowing.

##### Infinity is bigger than you think - Numberphile
Numberphile – Numberphile

#### What's Bigger Than Infinity?

Does infinity plus one count?

##### What's Bigger Than Infinity?
Tipping Point Math – Tipping Point Math

#### The Opposite Of Infinity

Is it negative infinity?

##### The Opposite of Infinity - Numberphile
Numberphile – Numberphile

### Key Facts In This Video

1. The opposite of infinity would be the smallest number possible. 00:01

2. Infinitesimals were important to Leibniz and Newton when they invented calculus. 06:37

3. Limits can be used to work out the area below a curve without having to use infinitesimals. 10:36