Ancient black holes took longer time to heat early universe


Scientists have known for a while that during the early days of the universe, black holes were responsible for heating up the temperature of gas in space. However, a recent study in Israel may indicate that this may have happened earlier than previously expected.

When the universe was still young, black holes were formed from the death of certain early stars. These black holes were known to be responsible for raising the temperature of the early universe. However, the exact timeline of events has been furiously debated over the years. A new study conducted by the Tel Aviv University School of Physics and Astronomy has brought to light new information about the early universe. Moreover, the team also believes that its data will be vindicated if scientists use radio telescopes to measure the amount of hydrogen being emitted.

"It was previously believed that the heating occurred very early, but we discovered that this standard picture definitely depends on the precise energy with which the x-rays come out," says TAU School of Physics and Astronomy's Prof. Rennan Barkana in a statement to an Israeli news agency. "Taking into account up-to-date observations of nearby black-hole binaries changes the expectations for the history of cosmic heating. It results in a new prediction of an early time (when the universe was only 400 million years old) at which the sky was uniformly filled with radio waves emitted by the hydrogen gas."

It has previously been established that during the very early days of the universe, it was very dense and hot. However, as the universe expanded and became less dense, the temperature went down. The cooling process was only halted after the formation of black holes. Black hole binaries, which are systems consisting of a paired black hole and star, emit large amounts of radiation when the black hole sucks up hydrogen gas.

"The hydrogen gas itself emits radio radiation that we can see, and this emission carries a signature of the heating of the gas," says Barkana.

Scientists are gathering more data about the early days of the universe. While many questions still remain, Barkana and his colleagues hope that the newly gathered data will help shed more light on the subject.

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