Dark Energy

Dark Energy

News: Recently, an international team of researchers made the first direct detection of dark energy.They noticed certain unexpected results in the XENON1T experiment and write that dark energy may be responsible for it.

What is Dark Energy?
• More is unknown than is known. We know how much dark energy there is because we know how it affects the universe’s expansion. Other than that, it is a complete mystery. But it is an important mystery. It makes up about 68% of the universe.
• Dark Energy is a hypothetical form of energy that exerts a negative, repulsive pressure, behaving like the opposite of gravity.It is causing the rate of expansion of our universe to accelerate over time, rather than to slow down. That’s contrary to what one might expect from a universe that began in a Big Bang.
• Everything we see – the planets, moons, massive galaxies – makes up less than 5% of the universe. About 27% is dark matter and 68% is dark energy.
• While dark matter attracts and holds galaxies together, dark energy repels and causes the expansion of our universe.
• The existence of dark matter was suggested as early as the 1920s, while dark energy wasn’t discovered until 1998.
 

XENON1T experiment:
• It is the world’s most sensitive dark matter experiment and was operated deep underground at the INFN Laboratori Nazionali del Gran Sasso in Italy.
• It uses the dual-phase (liquid/gas) xenon technique and is located underground at the Laboratory Nazionali del Gran Sasso of INFN, Italy.

The theory of general relativity:
• The leading theory, however, considers dark energy a property of space. Albert Einstein was the first to understand that space was not simply empty. He also understood that more space could continue to come into existence. In his theory of general relativity, Einstein included a cosmological constant to account for the stationary universe scientists thought existed.
• After Hubble announced the expanding universe, Einstein called his constant his “biggest blunder.'
• But Einstein’s blunder may be the best fit for dark energy. Predicting that empty space can have its own energy, the constant indicates that as more space emerges, more energy would be added to the universe, increasing its expansion