Why must astronomers have a thorough understanding of light?

When stargazers go outside at night to look at the sky, they see the light from distant stars, planets, and galaxies. Light is crucial to astronomical discovery. Whether it’s from stars or other bright objects, light is something astronomers use all the time. Human eyes “see” (technically, they “detect”) visible light.

How does light play a role in astronomy?

By observing ultraviolet light, scientists can see which galaxies are forming stars and where the stars are forming within those galaxies. Ultraviolet and visible light from the farthest galaxies is stretched into infrared light as it travels across the expanding universe.

How do astronomers use light to help them understand the history of the universe?

“You take the light from a star, planet or galaxy and pass it through a spectroscope, which is a bit like a prism letting you split the light into its component colours. “It lets you see the chemicals being absorbed or emitted by the light source. From this you can work out all sorts of things,” says Watson.

What can astronomers learn from a star’s light?

From spectral lines astronomers can determine not only the element, but the temperature and density of that element in the star. The spectral line also can tell us about any magnetic field of the star. The width of the line can tell us how fast the material is moving. We can learn about winds in stars from this.