Waves
We are all familiar with waves; from ripples on the surface of a pond to the swell of the ocean. A wave is just a regular vibration that travels through something, like air or water.
Unlike sound, light waves can travel through nothing, like the vacuum of space. This means that the light coming from stars, and all other objects in space is able to reach us here on Earth.
Electromagnetic Spectrum
This light that we see is just one small chunk of light which is made by stars. We often call the small range of wavelengths our eyes can detect, optical, or visible light.
- Properties of each Electromagnetic Wave
Moving through the electromagnetic spectrum we go from short to long wavelengths and the frequency of the waves gets smaller. We go from high-energy to low-energy.
Spectra
Even though light often looks white, it is made up of lots of different colours all added together.
Astronomers often want to know exactly what colours of light there are coming from a star or galaxy. To measure this, they use an instrument called a spectroscope. These have prisms, or gratings, inside them which separate the light. They then record the data.
Light
When we talk about light we usually mean the light we can see with our eyes. This is also called visible or optical light.
- How does light travel?
For us to see, light must travel from a light source to our eye. The light we see on Earth travels in straight lines.
Anything in the path of light has an effect on what we see. For example, a window is transparent – this means that the light can pass straight through it.
Gravitational Waves
Gravitational waves are tiny, invisible ripples in space. They travel for huge distances at the speed of light. The waves squeeze and stretch any objects they pass, but only by a tiny amount.
- Evidence for Gravitational Waves
On 14th September 2015, scientists announced they had the first evidence for gravitational waves. This was nearly 100 years after Einstein published his work.
Measure the Speed of Light
Make Your Own Spectroscope
Spectroscopy involves splitting light into its different wavelengths. Each chemical element emits or absorbs a unique spectrum&n
Telescopes Quiz
Telescopes are used to magnify distant objects. They are a vital tool for astronomy. Over the last few hundred years, scientists and engineers have built bigger and better telescopes, revealing the mysteries of the Universe. But how much do you know about telescopes on Earth and beyond?