A star is reborn: how Hubble astronomers saw the earliest light

The first stars to exist in our universe were born less than one billion years after the Bigbang. The Hubble space telescope was able to detect light from it.

Most of the time, the telescope gives us detailed images of nearby and distant galaxies. The star was discovered by a team of astronomers from the University of Baltimore. The team looked at a selection of images from the Hubble looking for clues.

Astronomers are not newcomers when it comes to observing ancient light. This week it revealed amazing pictures of a galaxy that was half a billion years before Earendel. Although this surpasses what we expected Hubble could do, it isn't as remarkable a feat as resolving a single star, and when you see the shapeless smudge of that early galaxy, it brings it home how special Earendel is.

In detective fiction, the sleuth uses a magnifying glass to look at evidence left at the crime scene. Nature provides us with an alternative method that is much more powerful than the one we can use.

Light from the background stars is bent around the cluster, just like light bends in a magnifying glass. This effect is used in astronomy to see objects that are too far away to see otherwise. We must follow where the universe leads us if we want to move galaxies to amplify where we want.

In one snapshot, the team saw a distorted and magnified galaxy. There is nothing new there. There was a bright smudge in that distorted galaxy. One star in the galaxy aligned with the lens so precisely that it made it seem big and bright. The colour of the light from Earendel is indicative of ancient light.

Light has different properties depending on its energy, and can be seen through a rainbow of optical light and high energy X-rays. On its journey towards us, Starlight loses energy, sliding down the spectrum. Earendel's light is very red, and it seems that it has traveled a lot over the past 13 billion years, placing it in the era of the first stars. The views of individual stars within this era have not been seen before.

Earendel is close to the oldest generation of stars. This era is similar to the early evolution of humankind. There are important differences between our ancestors and us. It is with the universe now, compared to the universe then. We need to go back as far as possible to fill the gaps.

Earendel's observation is a new record. The previous record was smashed to smithereens, and it might be a record that is here to stay. The light from Earendel is so faint that we wouldn't have been able to see it. There is no guarantee that we will see another cluster with the same alignment and stars any further away. Good luck has helped over the finish line many years of hard work, expertise and speculation, in the same way that other major scientific advances have.

There is a chance of mistaken identity when we test our powers of observation. While light from a distant blue star will have lost energy so it appears red, we could just be looking at something much closer that is red to begin with. The chances of a random, reddish star lining up with that old, distorted galaxy is small, but not impossible, so the team will use a new space telescope to rule out the suspect.

A black hole can look like a star if the surrounding matter spirals inwards in a certain way. X-ray observations will help us decide. It is not new to combine different wavelengths of light in everyday life. Imagine seeing a doctor for a broken arm. They will examine your arm in a well-lit room, but how do they know if it is broken? How bad is a break? Will you ever play tennis again? You would hope they would give you an X-ray. To distinguish what we are seeing in space, we need to use different light wavelength in a similar way to a doctor.

Earendel looks to be the farthest star we have ever detected. A chance alignment of objects in the sky has provided exciting evidence of the universe's infancy. We might be on the trail of the faintest stars in the universe, but we're going to need more than a magnifying glass. We are going to have to think on a different wavelength.