As we know that our solar system has eight planets. Because Pluto does not meet the third condition, it is classified as a dwarf planet. Planets that are closer to the sun travel quicker than planets that are farther away. Moving away from sun, our planet Earth has 3rd number. This is the most wonderful planet in our solar system as it has water, mountains, colors, oceans, trees, sun, stars, air, suitable temperature and all other things that are needed for life. It has days, nights, sunset, sunrise, seasons and atmosphere. One interesting question is that what causes day and night on earth. To answer this question, we must understand the motion and position of earth around sun.
To be classified as a planet, a celestial body must meet some criteria that includes:
- It revolves around the sun.
- It has enough mass to take on a spherical shape.
- It has a well-defined orbital neighborhood.
How day and night are formed?
What causes day and night on earth? The answer is that the Earth is rotating even if you can’t feel it. Earth spins on its axis once every 24 hours, carrying all of us with it. We have daylight when we are on the side of the Earth that faces the Sun. We are relocated to the side facing away from our Sun as Earth continues to rotate, and we have night time. As earth rotates counterclockwise so we get daylight and darkness from east to west. This causes day and night cycle.
Day and night are caused by the spin motion of earth. Earth completes its one spin round in 24 hours and its orbital motion around sun also takes exactly same time. So we feel earth as stationary, while it is in motion continuously. Earth axis is tilted by 23.5 degrees. The portion of earth that is near to the sun has day time and the other portion has night time. However, the people who are living in the poles areas have longer days, as those areas continuously get sun light. Thus spin motion of earth is the reason behind the formation of day and night.
Sunrise, sunset, day and night cycle (diurnal cycle) are commonplace for most people on the world. The length of day and night might vary by a few hours as a result of seasonal variations that occur with each passing year. However, the Sun does not set in some parts of the Earth (for example, the poles) at certain times of the year. There are other times of the year, when a single night might continue for several days.
Naturally, this raises a number of questions. What causes the day-night cycle, and why don’t all parts of the globe experience the same patterns? As with many other seasonal experiences, the answer has to do with two facts: One, the Earth rotates on its axis as it orbits the Sun. And two, the fact that Earth’s axis is tilted. That is what causes day and night on earth.
Because the Earth rotates from west to east, the Sun always seems to rise on the eastern horizon and set on the western. The Earth would appear to be revolving counter-clockwise if viewed from above, looking down on the northern polar area. However, it appears to be rotating clockwise when observed from the southern polar area.
Do other planets have day and night?
Yes, definitely! Our solar system’s planets all revolve on their axes (as does our Sun!) and hence have day and night cycles. The length of day and night differs and the cycles are complicated further by the tilt of a planet’s axis and its velocity of orbit. Some planets spin faster than Earth, while others spin slower. The day and night cycle on Mars is comparable to that on Earth. Every 24.6 hours, Mars revolves on its axis. Every 243 Earth days, Venus rotates once on its axis. Similarly, the day and night cycle of Mercury is more complicated.
During each orbit around the Sun, Mercury spins one-and-a-half times. As a result, Mercury’s day lasts 176 Earth days from sunrise to sunrise. The bigger planets rotate at a significantly higher rate. Jupiter rotates once every ten hours, Saturn once every eleven hours, and Neptune once every sixteen hours. Pluto, at the outermost limits of our solar system, rotates once every 6.4 days on its axis.
Why does Earth’s day length change during the year?
Every region on Earth gets 12 hours of light a day on average, however the number of hours of daylight on any one day of the year varies from place to place. Only around 12 hours of light are received by locations near the equator each day. The North Pole, on the other hand, has 24 hours of brightness for a few months in the summer and months of darkness in the winter. A long dawn and a lengthy sunset divide these two annual seasons of light and gloom.