Satellites and their uses

When we look up at the starry sky at night, it's natural to feel a sense of wonder. Above us, there are not only stars and planets, but also many man-made objects called satellites. These amazing machines orbit our Earth and serve many important purposes. In this explainer, we'll learn all about satellites, how they work, and their uses in our solar system and beyond.

What are satellites?

A satellite is an object that orbits or revolves around a planet or star. There are two main types of satellites: natural and artificial. Natural satellites, such as the Moon, orbit planets and are not made by humans. However, artificial satellites are man-made and sent into space for various purposes. When people usually refer to "satellites," they are talking about artificial satellites.

How do satellites stay in orbit?

Satellites stay in orbit due to two main factors: gravity and momentum. Gravity is the invisible force that pulls objects toward one another. It's what keeps the planets orbiting around the Sun and the Moon orbiting the Earth. The satellite is launched into space with the help of a rocket. During launch, it gains enough speed to balance the pull of Earth's gravity.

Imagine you are tying a ball to a thread and spinning it in a circle. The ball wants to fly in a straight line due to something called inertia, but the thread keeps pulling it towards itself. Similarly, gravity keeps pulling the satellite towards the Earth while its momentum takes it forward, resulting in an orbit.

Gravity (g) = Force (F) / Mass (m)

Types of satellites

There are many types of satellites, each designed for specific purposes. Here are some common types:

• Communication satellites: These are used to send and receive signals for telephone, television and internet services. They help people around the world stay connected.
• Weather satellites: As their name suggests, they help observe and predict weather conditions on Earth. By taking pictures of cloud patterns, weather satellites can forecast storms, hurricanes, and other severe weather conditions.
• Navigation satellites: These satellites help pinpoint locations using the Global Positioning System (GPS). They are vital for traveling, guiding ships, airplanes, and even cars to their destinations.
• Scientific satellites: These collect data for scientific studies. They help scientists learn more about space, stars, and planets. Some also monitor Earth's resources and climate change.
• Earth observation satellites: These take images of the Earth's surface that help in urban planning, agriculture, and monitoring environmental changes.

Circular and elliptical orbits

Satellites move on different orbital paths around the Earth. The shape of these orbits can be circular or elliptical.

In a circular orbit, the satellite maintains a fixed distance from Earth. This is useful for satellites that monitor weather or aid in communications, because they stay in the same position relative to the Earth's surface.

On the other hand, an elliptical orbit means that the satellite's distance from Earth varies, coming closer at some points and farther away at others. This type of orbit is beneficial for scientific studies, as it allows the satellite to collect data from different distances.

Geostationary and polar orbits

Some satellites travel on specific paths called geostationary or polar orbits.

Geostationary orbit: In this orbit the satellite remains in a fixed position above a part of the Earth. It rotates at a speed equal to the speed of the Earth's rotation. Communication satellites often use this orbit.

Polar orbit: A satellite in this orbit travels over the poles and can see the entire surface of Earth as the planet rotates. Earth observation and mapping satellites often use this orbit to collect extensive data.

Importance of satellites

Satellites have revolutionised the way we communicate, observe and understand our world. They are vital to global communications networks, allowing people in different countries to talk instantly, make video calls and share data.

In weather forecasting, satellites provide up-to-the-minute information that helps predict storms, giving people time to prepare for bad weather and saving lives and property.

Satellites help with navigation through GPS, making travel more efficient and safer. Additionally, they are vital for scientific research, contributing to our understanding of the universe, earthquakes, and environmental patterns.

Conclusion

Satellites play a vital role in our daily lives, even if we can't see them. They connect us, inform us about the weather, help us find our way, and allow scientists to explore the far reaches of space. Understanding how satellites work and how they are used teaches us the great power of human innovation and its potential to benefit life on Earth.

Comments