Ancient Egypt was a civilization of ancient Northeastern Africa, concentrated along the lower reaches of the Nile River - geographically Lower Egypt and Upper Egypt, in the place that is now occupied by the countries of Egypt and Sudan.
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, or, equivalently, the angle between its equatorial plane and orbital plane.
A calendar is a system of organizing days for social, religious, commercial or administrative purposes.
Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years).
The amount of heat energy received at any location on the globe is a direct effect of Sun angle on climate, as the angle at which sunlight strikes the Earth varies by location, time of day, and season due to the Earth's orbit around the Sun and the Earth's rotation around its tilted axis.
The heliacal rising or star rise of a star, star cluster, or galaxy occurs annually when it becomes visible above the eastern horizon for a moment before sunrise, after a period of less than a year when it had not been visible.
The Nile River (النيل, Egyptian Arabic en-Nīl, Standard Arabic an-Nīl; ⲫⲓⲁⲣⲱ, P(h)iaro; Ancient Egyptian: Ḥ'pī and Jtrw; Biblical Hebrew:, Ha-Ye'or or, Ha-Shiḥor) is a major north-flowing river in northeastern Africa, and is commonly regarded as the longest river in the world, though some sources cite the Amazon River as the longest.
Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states.
Science, also widely referred to as Science Magazine, is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals.
A season is a division of the year marked by changes in weather, ecology, and amount of daylight.
Sirius (a romanization of Greek Σείριος, Seirios,."glowing" or "scorching") is a star system and the brightest star in the Earth's night sky.
A tropical year (also known as a solar year) is the time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice.
A year is the orbital period of the Earth moving in its orbit around the Sun.