
Webb's First Deep Field
One of Webb’s earliest and most iconic images, is its stunning Deep Field view of the galaxy cluster SMACS 0723. This distant view overflows with detail, as we peer back in time and see this galaxy cluster as it appeared 4.6 billion years ago. Thousands of galaxies of different colors and brightness are captured. Nearer to earth are bright stars, appearing with six large diffraction spikes (caused by the unique structure of Webb’s many hexagonal mirrors). Some galaxies appear contorted, their light being stretched by the strong gravitational forces while en route to us as it passes by other galaxy clusters (this effect known as “gravitational lensing”, which also magnifies the light). All of this, captured by Webb in roughly a 12.5hr exposure. By comparison, similar images from Hubble took weeks of exposure to create. This already impressive image becomes truly astounding when you fully comprehend the tiny field of view in the night sky it represents. If you were to pinch a grain of sand between your fingers, and hold that at arms length up to the sky, that grain of sand would represent the field of view depicted here. In that tiniest of spaces, all of these galaxies are revealed.