Apparently those stars were created much earlier than expected.

When did the first stars come into existence? And how did they originate? These are pressing questions that astronomers unfortunately still have to answer for. The search for the very first stars and galaxies is therefore one of the greatest challenges in astronomy. However, the questions can be answered. This is with the help of the Hubble space telescope that can observe the universe up to five hundred million years after the Big Bang.

First stars
In a new study, researchers decided to look for the first generation stars in the very young universe. What we know is that the first stars to emerge after the Big Bang were composed almost entirely of elements such as hydrogen, helium and small amounts of lithium. Other (heavier) elements that we find in stars today were produced in the cores of these first stars and thrown into space during supernova explosions. The next generation of stars emerged from the debris of the first generation and included the heavier elements that the first generation of stars had produced, while they themselves also produced more heavier elements. It means that the chemical composition of the first stars was fundamentally different from that of all later stars.

Big Bang
Using the Hubble space telescope – and supporting data from NASA’s Spitzer space telescope and the Chilean Very Large Telescope – researchers scanned the early universe for the first generation stars between about 500 million to 1 billion years after the Big Bang. To this end, the team developed a new technique that extinguished the light from bright galaxies in the foreground. This allowed the researchers to discover galaxies with lower masses than have ever been observed with Hubble. The search ended in nothing. “We found no evidence for the first generation stars in this cosmic time interval,” said researcher Rachana Bhatawdekar.

This image from the Hubble Space Telescope shows the cluster MACS J0416. This is one of six clusters examined in this study to find the first generation stars. Image: NASA, ESA, and M. Montes (University of New South Wales, Sydney, Australia)

–

The findings are telling. It means that the formation of the first stars and galaxies took place much earlier in the very young universe than previously thought. “The results therefore have profound consequences,” says Bhatawdekar. “It also supports the idea that light and faint galaxies were responsible for reionization early in the Universe.”

More about reionization
With the arrival of the first stars, the so-called “Dark Ages” came to an end and the era of reionization began. The radiation from the first stars did a lot with the environment: it caused the cold and neutral hydrogen to become warm and ionized. The period of reionization in the early universe indicates the moment when the neutral intergalactic medium was ionized by the first stars and galaxies.

Thanks to the study, the researchers push the formation of the first stars further back on the timeline. This gives researchers increasingly better insight into when the first stars must have formed. That the first stars are younger than expected is good news for the James Webb telescope who will soon be looking for the first stars. Since they are younger than expected, the telescope will be able to find them more easily. When the James Webb will take to the skies is just a little coffee grounds. Due to the coronavirus outbreak, NASA decided suspend work on the promising telescope. There is no doubt that the telescope will be launched. Astronomers hope that the telescope will provide more insight into the origin of the universe. It is also expected to play a major role in the search for extraterrestrial life; the telescope can search the atmosphere of exoplanets and search for signals of life.