Context: The European Space Agency (ESA) plans to survey billions of galaxies using the Euclid Space Telescope, which is due to launch on July 1 from Cape Canaveral in Florida on a SpaceX Falcon 9 rocket.
Euclid Mission:
- The mission is part of ESA’s ‘Cosmic Vision’ programme which plans to explore the origin and components of the Universe and the laws that govern it.
- The payload will have a 1.2 metre-wide telescope, a visible-wavelength camera (VISible) and a near-infrared camera/spectrometer (NISP).
- VISible will look for tiny distortions in the shapes of distant galaxies from different points in time to understand the tussle between the pull of gravity and the push of dark energy.
- NISP will look at how quickly galaxies are moving away from each other, offering scientists insights into the effects of gravity.
- Stationed 1.5 million km away from the Earth, the telescope is expected to deliver images at least four times sharper than ground-based observatories.
- The Euclid mission hopes to understand the evolution of the Universe by looking at the light emitted from galaxies 10 billion years ago. Euclid’s main objective is to better understand dark matter and dark energy, which together make up 95% of the universe.
Dark Energy:
- Around 68% of the Universe is made of dark energy while dark matter makes up 27%. Only the remainder is composed of fermionic matter, i.e., things on the Earth, planets, stars, etc.
- Scientists theorised the existence of dark energy 25 years ago when a team of researchers found that instead of slowing down due to gravity (inwards pulling force), the expansion of the Universe was speeding up. Scientists hypothesised that this was happening due to a mysterious form of energy called dark energy.
- The expansion of the universe is accelerating. Previously it was thought that the pull of gravity will either slow down or even retract the expansion.
- Dark energy has been hypothesised as a repulsive force — a sort of anti-gravity. As our universe is expanding, it indicates that Dark Energy has a greater abundance than dark matter.
- Dark energy is a property of space so does not get diluted as space expands. As more space comes into existence, more of this energy-of-space appears. As a result, dark energy causes the universe to expand faster and faster.
- While Dark matter exerts a “pull” on the universe, Dark Energy has a contrasting expansionary effect.
Dark Matter:
- Dark matter has not yet been observed directly. It does not interact with matter and is completely invisible to light and other forms of electromagnetic radiation making it impossible to detect.
- Scientists are confident it exists because of the gravitational effects it has on galaxies and galaxy clusters.
