After several years of development and anticipation, the James Webb space telescope was launched on December 25, 2021, on Ariane flight VA256, with the intent to replace the famous Hubble space telescope as NASA’s flagship space telescope. With its spectral sensitivity ranging from the red part of the visible light portion of the electromagnetic spectrum to mid-infrared, the telescope has the ability to probe some of the oldest and most distant objects ever observed, with a sensitivity to detect cosmic sources 100 times fainter than Hubble’s detection limit. In astronomical observations, look back time refers to the time that has passed since light originating from a far-away object left that object to arrive now on Earth, as we observe the object. Light does not travel instantaneously, with a speed of just under 300,000km every second. This means that light from an object 300,000km away would take one second to reach us here on earth, and by observing that object from earth, we would always be observing that object as it were a second before. On cosmic scales, distances become so vast that looking at extremely far away objects can mean looking at light that left millions, or...
↧