Euclid Space Telescope Discovered Altieri’s Ring

Euclid space telescope has captured a rare Einstein ring (Altieri’s Ring) around galaxy NGC 6505, unveiling gravitational lensing effects and offering insights into dark matter distribution.

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Context: The Euclid space mission of the European Space Agency (ESA) recently spotted an Einstein ring (named Altieri’s Ring).

About Altieri’s Ring

In September 2023, the Euclid space telescope found an Einstein ring in a nearby galaxy called NGC 6505, which is 590 million light-years away.
It was discovered by the astronomer Bruno Altieri in an early test image, and later, clearer images confirmed its existence.
The ring was named Altieri’s Ring in his honor.
This ring is actually the distorted image of another galaxy 4.5 billion light-years away.

Significance of Altieri’s Ring Discovery

Altieri’s ring is special because it was found in NGC 6505, a well-studied nearby galaxy that has been known to astronomers since the 19th century.
Only five other gravitational lenses have been found at similar distances from Earth.

What is an Einstein Ring?

An Einstein ring is a rare ring of light that forms due to gravitational lensing.
Gravitational lensing occurs when a massive celestial object (a galaxy or cluster of galaxies) creates a gravitational field that bends and magnifies the light from a distant object behind it.
This was predicted by Albert Einstein’s General Theory of Relativity (1915), which stated that gravity can bend light around massive objects.
An Einstein ring forms only when the background galaxy, the lensing galaxy, and Earth align perfectly.
The first Einstein ring was discovered in 1987, and though more have been found since, they remain extremely rare.
- Less than 1% of galaxies are estimated to have an Einstein ring.
Einstein rings are not visible to the naked eye and can only be observed using advanced space telescopes like ESA’s Euclid.

Euclid Space Mission

It was launched by the European Space Agency (ESA) in July 2023.
Objective: To investigate dark matter and dark energy, which together make up 95% of the universe.
It is equipped with a 1.2-meter telescope, it captures high-resolution images and spectra of distant galaxies.
It operates from the Sun-Earth L2 orbit, about 1.5 million km from Earth.
It is expected to map billions of galaxies, creating a 3D cosmic map spanning 10 billion years.
Mission Duration – 6 Years.

Why Scientists Study Einstein Rings?

Understanding Dark Matter: Dark matter makes up 85% of the total matter in the universe, but it has never been directly observed.
- Gravitational lensing helps indirectly detect dark matter by observing how light bends around galaxies.
Studying Distant Galaxies: Some galaxies are too faint to be observed directly. Gravitational lensing magnifies their light, allowing scientists to study galaxies that would otherwise remain hidden.
Measuring the Expansion of the Universe: The universe is expanding, stretching space between Earth and other galaxies.
- Einstein rings provide data on how fast galaxies are moving apart, helping refine measurements of cosmic expansion.