(ORDO NEWS) — Astronomers do not know exactly when the first stars appeared in the Universe, because they have not yet been discovered.
Now, new observations with the Hubble Space Telescope show that the first stars and galaxies could have formed even earlier than previously thought.
A group of astronomers used Hubble to look back in time (and space) as far as possible, hoping to study this first generation of stars in the early Universe, called the stars of Population III.
Hubble looked back when the universe was only 500 million years old – which is considered the limit of the telescope – but found no evidence of the very first stars.
Population III stars should be composed entirely of hydrogen, helium, and lithium, the only elements that existed before the processes in the nuclei of these stars created heavier elements such as oxygen, nitrogen, carbon, and iron.
Rahana Bhatavdekar of the European Space Agency conducted a study studying the early Universe about 500 to 1 billion years after the Big Bang.
Astronomers have studied the star cluster MACSJ0416 and the surrounding space using the Hubble Space Telescope, as well as supporting data from the Spitzer Space Telescope and the ground-based Very Large Telescope of the European Southern Observatory.
The observations were part of the Border Fields program, in which six distant galaxy clusters were observed between 2012 and 2017.
The data were obtained using the effect of gravitational lensing, when the masses of clusters of foreground galaxies are large enough to bend and amplify light from more distant objects behind them. This allows Hubble to use “space loops” to study objects that go beyond its nominal operational capabilities.
Astronomers have discovered galaxies with lower masses than ever before observed at a distance corresponding to when the universe was less than a billion years old.
“But we did not find any evidence of the existence of the stars of the first Generation III in this cosmic time interval,” said Bhatavdekar.
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