Earth Day takes place on 22 April and this year's theme is 'Invest in Our Planet'. Here are some ways to get involved, as chosen by the website EcoWatch., The origins of Earth Day first started 50 years ago, on April 22, 1970 when millions of Americans took to the streets to voice their concern over the treatment of the planet. Since then, Earth Day has become an international day promoting conservation and sustainability, whilst celebrating the earth's natural beauty., A "day" on Jupiter (its period of rotation) is about 9.9 Earth hours.So there are approximately 2.4 Jupiter days in an Earth Day., However, all areas get the same "total" sunlight in a year, equal to 6 months of sunlight, so that every location will average out to 12 hours of day and 12 hours of night., Is day or night colder? Generally, night is colder than day. This is because during the day, the sun warms the Earth and its atmosphere, while at night, without sunlight, the Earth loses heat to , The calendar shifts one day each year due to the discrepancy between the solar year (365.24 days) and the calendar year (365 days)..