Question 1

What is the Day/Night Solar Terminator line shown on the map?

Accepted Answer

The solar terminator (also called the twilight zone or grey line) is the mathematical boundary separating the sunlit day hemisphere of Earth from the dark night hemisphere. Because Earth is tilted at an axial angle of approximately 23.44°, this boundary shifts continuously throughout the year, causing longer summer days and shorter winter days.

Question 2

How accurate are the live clocks displayed when hovering over city pins?

Accepted Answer

Every city clock on the TimeNumbers world map computes time in-memory directly from canonical IANA time zone rules and native browser internationalization engine. Clocks are synchronized against atomic standards and maintain precision of ±0.01 seconds without background tab drift.

Question 3

What do the curved lines connecting cities on the map represent?

Accepted Answer

The illuminated curved arcs represent great-circle geodesic paths connecting key global financial, technological, and transport hubs. These represent the shortest flight trajectories across Earth’s spherical surface and visualize international time synchronizations.

Question 4

Why are there 24 longitudinal lines across the world map?

Accepted Answer

Earth rotates 360° of longitude in approximately 24 hours, which equates to 15° of longitude per hour. The 1884 International Meridian Conference in Washington, D.C. established the Prime Meridian (0°) through Greenwich, London, creating 24 standard 15-degree longitudinal time zone bands.

Question 5

Can I simulate future or past time on the map?

Accepted Answer

Yes. Use the interactive 24-Hour Solar Scrubber slider at the top of the map to shift the simulated hour up to ±12 hours. You can observe the solar terminator glide across continents in real time and inspect simulated city times.

Interactive World Time & Astronomical Map

Planetary World Clock & Solar Map

Paris, France

The Astronomical Solar Terminator

Greenwich Prime Meridian (0°)

Atomic NTP Clock Synchronization

Frequently Asked Questions About the World Time Map

Explore Global Time & Related Directories

Precision Horology & Global Time Tools

High-Volume City Time Differences

Global Financial & Metropolitan Capitals