What is stardust?

2 min read

While ‘stardust’ is a poetic rather than technical term, the heavier atoms thrown out by stars into the interstellar medium really do clump together in the form of tiny dust grains. As these grains drift around the universe, they can sometimes be accreted onto asteroids in our own Solar System, and if a fragment of one of these makes it to the surface of Earth in the form of a meteorite, we can actually get our hands on a grain or two of ‘stardust’. In 2018, for example, a team at the University of North Carolina identified several grains of stellar dust that predate the formation of the Solar System.

A tiny interstellar dust grain containing carbon and silicon, found in a meteorite

OBSERVING THE BIRTH OF STARS

It’s easy to say that the Sun and its planets formed from elements created in a previous generation of stars, but how do we know that? We can see the same processes going on today, where the latest generation of stars are just being born. One of the most important tools allowing astronomers to study these processes is NASA’s James Webb Space Telescope, which has already stunned the world with its images. Aside from its huge size, the telescope is unusual in observing the universe mainly at infrared wavelengths. One of Webb’s principal science goals is to observe the process of star formation all the way from its initial stages to the formation of planetary systems like our own. Webb’s infrared vision can pierce through cosmic dust, not just with imaging sensors but also spectrometers that allow it to work out the chemical composition of what it’s seeing.

Webb’s gold-plated mirror is 25 square metres in area, larger than any other space telescope

WEBB VERSUS HUBBLE

This iconic view was first photographed by NASA’s Hubble Space Telescope in 1995, and then a second time in 2014 to produce the image below. Located in a star-forming region called the Eagle Nebula, the pillars are made of interstellar dust – or ‘stardust’ if you like. They m

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How It Works Magazine

21 December 2023

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