Nine Hundred Telescopes and One Chance a Year

<p><img alt="Webb's primary mirror is 6.5 metres across, built in 18 hexagonal segments that folded like a drop leaf table to fit inside a rocket. Reading an Earth twin's atmosphere would need something closer to thirty metres (Credit : NASA/Chris Gunn)" height="720" src="https://www.universetoday.com/article_images/5890960025-42fefef802-b_20260812_215904.jpg" width="1280" /></p><p>Reading the atmosphere of another world means catching starlight as it filters through that planet's air during a transit. The signal is about one part in a million and a true Earth twin transits only once a year, so you cannot simply repeat the measurement until the noise averages away. Each attempt has to work on its own. A team led from Shanghai has proposed the alternative to building an impossibly large mirror in space - nine hundred, one metre telescopes, flying together, watching the same transit and analysing the light together.</p>