How Do Satellites and Space Missions Shape Our View of the Solar System?

The eight planets of the solar system, in order from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; the Sun is the star at the centre of the solar system. The Sun provides the light and heat necessary for life on Earth and holds all the planets in orbit by its gravity. Each planet moves around the Sun in its own path, called an orbit. The planets are divided into inner planets (Mercury, Venus, Earth, Mars) and outer planets (Jupiter, Saturn, Uranus, Neptune), with the inner planets being closer to the Sun and mostly rocky, while the outer planets are farther and mostly made of gases. For example, when you see the Sun rise in the morning, you are looking at the same star that the planets orbit. Many students think Pluto is still a planet, but it is now classified as a 'dwarf planet' and is not included in the main list of eight planets.

Planets are large celestial bodies that revolve around the Sun and do not produce their own light, while natural satellites (moons) are smaller bodies that orbit planets. Besides planets and their moons, the solar system also contains asteroids (rocky objects mostly found between Mars and Jupiter), comets (icy bodies with bright tails when near the Sun), and meteors (small pieces of rock or metal that enter Earth's atmosphere and burn up, appearing as shooting stars). For example, Earth's natural satellite is the Moon, which you can see at night, while Jupiter has many moons. When you see a bright streak in the night sky, it is often a meteor burning up in the atmosphere. A common misconception is that all bright objects in the night sky are stars, but some are planets or even satellites.

Natural satellites are celestial bodies like the Moon that orbit planets, while artificial satellites are man-made objects placed in orbit around Earth or other planets for specific purposes. Artificial satellites are used for communication (such as television and mobile signals), weather forecasting (predicting rainfall and storms), navigation (helping ships and vehicles find their way), and remote sensing (collecting information about Earth's surface and environment). For example, when you use GPS on your phone to find directions, you are using signals from artificial satellites. In real life, weather forecasts on TV often rely on data sent by artificial satellites. Some students confuse natural and artificial satellites, but only artificial satellites are made by humans and serve specific technological purposes.

India has made important contributions to space exploration through missions led by ISRO (Indian Space Research Organisation). Aryabhata was India's first artificial satellite, which helped start the country's space program. Mangalyaan is a mission to Mars, showing India's ability to send spacecraft to other planets. Chandrayaan-3 is a mission to explore the Moon and study its surface. These missions have helped India gain knowledge about space, develop new technologies, and contribute to global scientific research. For example, images of the Moon and Mars sent by these missions are used by scientists to learn more about our solar system. Some students think only a few countries can send satellites or spacecraft, but India is one of the nations with active space missions.