News: The European Space Agency’s (ESA) Euclid space telescope discovered a rare Einstein ring around a galaxy called NGC 6505, located 590 million light-years from Earth. The images were captured in September 2023 and released on February 12, 2025.
About Einstein Ring
- An Einstein ring is a ring-shaped pattern of light formed due to gravitational lensing.
- It occurs when light from a distant galaxy is bent by the gravitational field of a massive celestial object (such as a galaxy or cluster) in front of it.
- The light bends in such a way that it appears as a circular ring around the foreground object.
- Einstein rings are extremely rare—less than 1% of galaxies produce them. The first Einstein ring was discovered in 1987, and only a few have been found since then.
- These rings are not visible to the naked eye and require powerful space telescopes like ESA’s Euclid or NASA’s Hubble.
Significance of Einstein Rings
- Study of Dark Matter: Dark matter is believed to make up 85% of the universe’s matter, but it cannot be directly observed as it does not emit light. Einstein rings help scientists study dark matter indirectly because gravitational lensing reveals the gravitational effect of dark matter.
- Understanding Distant Galaxies: These rings allow scientists to observe distant galaxies that would otherwise be too dim or far to detect. The magnifying effect helps astronomers study the structure and properties of these galaxies.
- Insights into the Expansion of the Universe: Einstein rings help measure cosmic distances and the rate of expansion of the universe. By analyzing light from distant galaxies, scientists track the stretching of space.
About Gravitational lensing
- Gravitational lensing is a phenomenon where light from a distant object is bent due to the gravitational pull of a massive object between the source and the observer.
- The massive object acts like a “lens,” distorting and magnifying the light from the distant galaxy.
- When the alignment is perfect, the light forms a complete circle—an Einstein ring.
