NightHemisphere

NightHemisphere[]

is a two-dimensional GeoGraphics primitive that represents the half of the Earth currently in darkness.

NightHemisphere[datespec]

represents the night half of the Earth for the specified date.

Details

  • datespec can be a DateObject or a string that resolves to a date.
  • A date without explicit time zone is assumed to use $TimeZone.

Examples

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Basic Examples  (2)

Shade the part of the Earth currently at nighttime:

Show the unilluminated part of the Earth on the summer solstice, using red lines to denote the Arctic and Antarctic Circles:

Use a different projection:

Scope  (3)

NightHemisphere[] gives a plot for the current date and time:

Using Now explicitly gives the same result:

Illustrate changes in the unilluminated hemisphere at different times of day and year:

Specify dates in other formats:

Properties & Relations  (2)

The terminator line separates the day and night hemispheres:

For a spherical model of the Earth, the night hemisphere is a geo disk:

The true night hemisphere and approximate darkness geo disk differ slightly when using an ellipsoidal model of the Earth:

Wolfram Research (2014), NightHemisphere, Wolfram Language function, https://reference.wolfram.com/language/ref/NightHemisphere.html.

Text

Wolfram Research (2014), NightHemisphere, Wolfram Language function, https://reference.wolfram.com/language/ref/NightHemisphere.html.

CMS

Wolfram Language. 2014. "NightHemisphere." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/NightHemisphere.html.

APA

Wolfram Language. (2014). NightHemisphere. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NightHemisphere.html

BibTeX

@misc{reference.wolfram_2025_nighthemisphere, author="Wolfram Research", title="{NightHemisphere}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/NightHemisphere.html}", note=[Accessed: 31-July-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_nighthemisphere, organization={Wolfram Research}, title={NightHemisphere}, year={2014}, url={https://reference.wolfram.com/language/ref/NightHemisphere.html}, note=[Accessed: 31-July-2025 ]}