In the field of astronomy, there are various types of electromagnetic waves besides visible light. Astronomers use different instruments to study these waves and gather information about the universe. 'All the light we cannot see' refers to the hidden aspects of the universe beyond visible light.
In the field of astronomy, visible light is what most people associate with studying celestial objects. However, visible light represents only a small portion of the electromagnetic spectrum. There are many other types of electromagnetic waves, such as radio waves, microwaves, infrared waves, ultraviolet waves, X-rays, and gamma rays. These waves carry information about the universe that is not visible to our eyes.
Astronomers use various instruments, such as telescopes equipped with detectors sensitive to different wavelengths, to observe and study celestial objects. For example, radio telescopes can detect radio waves emitted by stars and galaxies, while X-ray telescopes can detect X-rays emitted by high-energy objects. By studying different wavelengths of light, astronomers can gather more comprehensive and detailed information about the universe.
So, the phrase 'all the light we cannot see' refers to the fact that there is a vast amount of information about the universe that is beyond the range of visible light. By using instruments that can detect different types of electromagnetic waves, astronomers can explore and understand the hidden aspects of the universe.