Stars emit all kinds of radiation including light waves, cosmic rays, gamma rays, and X-rays. When we look at stars, we can only see the light waves.
But using cameras that can 'see' the other wavelengths, particularly X-rays, then convert them to light waves that we CAN see, we notice a lot of things that simply do not show up by looking at the stars' light waves.
Electrons impact at high velocity on a tungsten anode. The tungsten emits the X-Rays, which are the electromagnetic waves.
telescopes
Ocean waves are made of matter
telescopesA telescope,books to study and find out what types of stars/constellations there are and maybe a astrolabe?
Telescopes.
An HR gram
The waves are called "electromagnetic waves". All types of EM waves can be used to study the Universe.
Most stars and many other objects in space emit radio and microwave radiation. Even the big bag emitted electromagnetic radiation.
Telescopes
The energy is called electromagnetic energy. It is the energy carried by electromagnetic waves. In principle, any frequency of EM waves can be used to gather information about objects in outer space.
ultrasonic waves are not used but radio waves are used in radar technology because ultra sonic waves generally create an image out of the object while we have to confine our study to the geometrical measurements only
Spectroscope