When you read about the environment around us, you learned that there are natural and artificial elements.
The Sun is a natural element, and it is the nearest star to the Earth.
What is the Solar System?
The Sun and the comets, the meteors and the eight planets (including their natural satellites) that move around the Sun make up the Solar System.
What are the eight planets that make up the Solar System?
The planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto is no longer considered by scientists as a solar system planet.
After heated discussions, Pluto was then excluded from the Solar System model and reclassified as a dwarf planet.
What is a full day, and why is it so?
When we look at the sky early in the morning, we see the Sun rising at a certain point; when we look at the sky in the evening, the Sun is setting at another point.
The time elapsed between two sunrises corresponds to a full day (day and night) and actually results from the rotation movement of the Earth around its axis.
How are cardinal points determined? Which are they?
The apparent movement of the Sun during the course of the day serves as a reference for determining the main
cardinal points – north, south, east and west.
Does the Sun revolve around the Earth? Or is the Earth revolving around the Sun?
Still due to the apparent movement of the Sun, you may believe that it is the Sun that turns around the Earth . For centuries people also believed the same.
But in fact it is the Earth (as well as every other planet) that orbits around the Sun (in an elliptical course called terrestrial orbit.
What is a solar year and how long is it?
The time taken by the Earth to make one complete revolution, the so-called translation movement around the Sun represents one year and it has the approximate duration of 365 days and 6 hours.
During this period of one year, the Earth reaches four major points in its orbit – the equinoxes and the solstices – that are the primary cause of the seasons.
How important is the Sun?
The Sun is a source of heat and life for animals and plants. Without sunlight, green plants would not be able to fix the carbon needed to produce chlorophyll,
the substance (pigment) that gives leaves their green colour. The production of chlorophyll from sunlight is called photosynthesis.
To learn more about the Sun an the Solar System you may visit the Peter Harrison Planetarium and Royal Observatory if you are in London,
or the Lisbon Calouste Gulbenkian Planetarium if you are in Portugal.
