A year or annus is the orbital period of a planetary body, for example, the Earth, moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by change in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the planet, four seasons are generally recognized: spring, summer, autumn and winter. In tropical and subtropical regions, several geographical sectors do not present defined seasons; but in the seasonal tropics, the annual wet and dry seasons are recognized and tracked. A calendar year is an approximation of the number of days of the Earth's orbital period, as counted in a given calendar. The Gregorian calendar, or modern calendar, presents its calendar year to be either a common year of 365 days or a leap year of 366 days, as do the Julian calendars.

Read more in the app

Scientists Solve a 1,300-Year-Old Mystery

Ending a 50-year mystery, scientists reveal how bacteria can move

A 518-Million-Year-Old Worm Reveals Ancient Animal Ancestry

518-Million-Year-Old Armored Worm Fossil Found in China

Second Year Of Stalled Progress On The Sustainable Development Goals

What is the moon phase today? Lunar phases 2022

The time when a star came so close to our Sun, to roughly 1 light year of distance from the Solar System

The Discovery of 7,200-Year-Old Cheese and Other Ancient Food and Drink

Best air purifiers 2022: Top picks from Levoit, Dyson and more

Best protein powder for women 2022

3,000-year-old gold funeral mask unearthed in noble's tomb in China

Paleontologists Find 541-Million-Year-Old Green Alga Microfossils

3,300-year-old pink granite sarcophagus of Egyptian 'pyramid keeper' found at Saqqara

Best binoculars 2022: Top picks for stargazing, wildlife and more

Best humidifiers 2022: Relieve dry skin & allergy symptoms

7,000-year-old structure near Prague is older than Stonehenge, Egyptian pyramids

Refugees are inaccurately portrayed as a drain on the economy and public coffers. The sharp reduction in US refugee admissions since 2017 has cost the US economy over $9.1 billion per year and cost public coffers over $2.0 billion per year.

Ten must-see talks at this year's New Scientist Live

Vultures Prevent Tens of Millions of Metric Tons of Carbon Emissions Each Year

Best workout equipment for home 2022