*A Brief History of Time*).

If real numbers run on a left to right axis, imaginary numbers run up and down. They allow for negative answers to multiplication, for example -2 times -2 equals 4, but i2 times i2 equals -4. Scientists use these numbers to deal with difficult mathematics where real numbers won’t do the job, for example calculating the sum over histories of a particle.

Get the entire

*A Brief History of Time*LitChart as a printable PDF.## Imaginary numbers/time Term Timeline in *A Brief History of Time*

The timeline below shows where the term Imaginary numbers/time appears in

*A Brief History of Time*. The colored dots and icons indicate which themes are associated with that appearance.Chapter 8

**imaginary numbers**. This is a normal mathematical tool, by which numbers can be multiplied against themselves...

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**imaginary time**, that is,

**imaginary numbers**to represent time, which clears away any difference between space...

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**imaginary time**as the axis from pole to pole, though they may seem like them in real...

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**imaginary time**, undoing Hawking’s earlier work. But, singularity theories showed gravity to be so powerful at...

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Chapter 9

**imaginary time**. Imaginary time is no different from the dimensions of space. You can go back...

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