Webb Telescope Takes A Peek At The Oldest Stars In The Universe

The research used both data from Webb’s NIRCam instrument and archival data from the Hubble Space Telescope. Combining these two sources lets the researchers see the clusters in a range of different wavelengths to help understand them better.

The reason Webb is able to look back at some of the earliest galaxies is due to its sensitivity. It has highly sensitive instruments, which are helped by the fact it is in space, so it isn’t disturbed by water vapor in Earth’s atmosphere or the heat from the planet. This lets it view even very faint sources of infrared light.

Looking at very distant objects is like looking back in time because of the speed of light. As it takes time for light to travel to us, the more distant an object is, the earlier the light must have left it. This means that if we use Webb to observe these very faint, very distant galaxies, we are seeing them billions of years ago, as they were when the universe was young.

The globular clusters spotted in the deep field image are among the earliest that ever existed, according to the researchers.

“These newly identified clusters were formed close to the first time it was even possible to form stars,” said Mowla. “Because the Sparkler galaxy is much farther away than our own Milky Way, it is easier to determine the ages of its globular clusters. We are observing the Sparkler as it was nine billion years ago, when the universe was only four-and-a-half billion years old, looking at something that happened a long time ago.”