Earth, Sun & Moon Simulator
betaTurn the globe and the calendar to see day and night, the seasons, and where the Sun and Moon are for any place
How it works
The globe shows real country borders with their names and capitals, lit as the Earth is at the chosen instant: the bright line is where the Sun is rising or setting, and three darker bands mark civil, nautical and astronomical twilight. Pin any capital, city or point, then use two sliders — time of day turns the Earth, day of the year moves it around its orbit — or press Play at anything from real time to thirty days a second. Everything else follows the pin: Sun and Moon altitude and direction, sunrise, sunset, solar noon and the three twilights, day length and how it changed since yesterday, the Moon's phase drawn the way it looks from that spot, moonrise and moonset, and whether the Moon is actually visible. Charts show the Sun and Moon's height through the day, daylight through the year (with daylight-saving steps), a sky dome with the solstice paths, and Earth's orbit with the tilted axis that causes the seasons. Positions come from the astronomy-engine library, accurate to about an arc-minute, and all of it runs in your browser.
Questions
Why are there seasons?
Earth's axis is tilted 23.4° and keeps pointing the same way as it orbits. In June the northern hemisphere leans toward the Sun, so the Sun climbs higher and days are longer; in December it leans away. Distance is not the cause — Earth is closest to the Sun in early January. Slide the day of the year with the Sunrise line view to watch the day/night line tilt.
What is the line between day and night called?
The terminator. Because the atmosphere scatters light, darkness arrives in stages: civil twilight (Sun 0–6° below the horizon), nautical (6–12°) and astronomical (12–18°). The globe shades each band a little darker.
How do I see when the Moon is visible from my city?
Pin the city, then read the Moon card: it shows the Moon's altitude and direction now, moonrise and moonset, and whether it is up in a dark sky. Turn on 'Where the Moon is up' to draw the half of the Earth that can see it.
Does the Moon look the same from everywhere?
The phase is the same worldwide, but its orientation is not: the lit edge is tilted differently depending on latitude and time, and it appears upside-down from the southern hemisphere. The Moon disk is drawn as seen from the pinned place.
How accurate is it?
Sun and Moon positions use astronomy-engine and are good to roughly an arc-minute; rise and set times to within a minute for a flat horizon with standard refraction. Mountains, buildings and unusual weather change what you actually see.
Can I check the midnight sun or polar night?
Yes. Pin Longyearbyen, Tromsø, Reykjavík or an Antarctic station and slide the date: the tool reports a 24-hour day or a day with no sunrise, and the year chart shows the whole pattern.