From UPSC perspective, the following things are important :
Prelims level : Dark Energy, Dark Energy
Mains level : Theory of expansion of the universe
Last week, an international team of researchers has made the first direct detection of dark energy.
About the Project
- The XENON1T experiment is the world’s most sensitive dark matter experiment and was operated deep underground at the INFN Laboratori Nazionali del Gran Sasso in Italy.
- The finding also suggests that experiments like XENON1T, which are designed to detect dark matter, could also be used to detect dark energy.
What is Dark Energy?
- Dark energy is an unknown form of energy that affects the universe on the largest scales.
- The first observational evidence for its existence came from measurements of supernovae, which showed that the universe does not expand at a constant rate; rather, the expansion of the universe is accelerating.
- Prior to these observations, it was thought that all forms of matter and energy in the universe would only cause the expansion to slow down over time.
- Measurements of the cosmic microwave background suggest the universe began in a hot Big Bang, from which general relativity explains its evolution and the subsequent large-scale motion.
- Without introducing a new form of energy, there was no way to explain how an accelerating universe could be measured.
Does it exist?
- Since the 1990s, dark energy has been the most accepted premise to account for the accelerated expansion.
- As of 2021, there are active areas of cosmology research aimed at understanding the fundamental nature of dark energy.
Dark energy Vs Dark matter
- Everything we see – the planets, moons, massive galaxies, you, me, this website – 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.