Some telescopes capture starlight shining through the atmospheres of exoplanets. Gases in these atmospheres will block out certain slices of the spectrum in this starlight, in a way that scientists can read like a bar code – a light-sifting method known as spectroscopy.

In a sense, they will take “samples” of exoplanet atmospheres. In some cases, this might include searching for potential signs of life in these gases – biosignatures – although that investigation is far more likely to be taken up by even more powerful space telescopes in the future.