And when observers take a spectrum of the galaxy, the diffraction grating of the spectrograph disperses the light over a large area on the detector, rendering the signal even fainter at each wavelength.

• 而当观测者撷取星系光谱时，光谱仪的绕射光栅会把光分散到侦测器上一个很大的?围，导致每个波长上的讯号更加微弱。