State-of-the-art technology can send people to the moon and satellites to the edge of the Solar System. But these distances are nothing to the vast interstellar space . So how do we discover and study something as big as the universe when we can barely reach it? The answer is light .
Just as sunlight can disperse into rainbow colors, separating light from distant objects exposes different bands of color depending on their source. These special colored stripes can not only reveal the composition of an object, but also indicate its temperature and pressure.
Looking at the light from the sun, we see black streaks in the rainbow, these streaks are typical traces of atoms. Each type of atom absorbs a different wavelength and the absorption content is based on the number of atoms. So, by observing the amount of light lost on wavelengths, we know the elements in the Sun's atmosphere and their density.
We can also explore more from the light. If you've ever stood at a train station, you'll probably realize that the noise emanating from the train depends on its direction of travel with increased pitch. When the train runs towards you and decrease when the train runs away, this is due to the Doppler effect of sound waves .
Sound is not transmitted in a vacuum, no one can hear your screams in outer space. But light is possible, applying the Doppler effect to the light source, if the light source is near us, the wavelength will be short and the light will become greener. If light from a source is moving further away, it will have a longer wavelength and will become redder.
By analyzing the color range based on the movement of light from objects observed by the telescope, we can know what it is made of, how hot it is and how much pressure it is, we also know if it moves, in which direction and how fast.
But we are not confined to the wavelengths. Studying radio waves tells us about the ancient history of the universe. Research infrared rays from cold objects like gas and dust in space and ultraviolet rays from young stars. Wavelength research gives us a more complete picture of the universe. Therefore, astronomers use a variety of glasses from the spectra of infrared, ultraviolet to X-rays, from radio telescopes to artificial satellites.
The first person to study light from distant galaxies was Edwin Hubble , Hubble discovered that the universe is expanding because galaxies are moving away from us and the further away they are, the faster the speed of travel the faster. And yet, when we look at light from a quiet region of the universe, we see signs of hydrogen and helium, at a ratio of 3: 1, which also suggests that the original universe only consisted of 2. Gases: Hydrogen and Helium . However, there are still many other mysteries that we have yet to unravel. Want to know the secret of the universe? Follow the light.