What is the Euclid Space Telescope? What is its main objective?🔗

The Euclid Space Telescope is a mission by the European Space Agency (ESA) designed to unravel the mysteries of the “Dark Universe.” Launched on July 1, 2023, its primary goal is to investigate the nature of dark matter and dark energy. By precisely measuring and analyzing the expansion of the universe, Euclid aims to shed light on how dark energy drives this phenomenon.

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How does the Euclid Telescope work? What instruments does it use?🔗

The Euclid Telescope features a 1.2-meter mirror that collects light from distant galaxies. This light is then analyzed by two key instruments:

• Visible Light Camera (VIS): This camera captures high-resolution images in visible light, ranging from 550 nm (green) to 900 nm (near-infrared). Equipped with 36 CCDs totaling about 600 megapixels, it helps map the distribution of galaxies.
• Near-Infrared Spectrometer and Photometer (NISP): Operating in the infrared range of 900-2000 nm, this instrument images galaxies and measures their spectra (distribution) of galaxies. It uses a grid of 16 detectors to gather this data.

Together, these tools allow Euclid to observe the universe in both visible and infrared light, providing a comprehensive view of cosmic structures.

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How will the Euclid Telescope study dark energy and dark matter?🔗

Euclid employs two main techniques to explore these mysterious components:

• Weak Gravitational Lensing: Dark matter, though invisible, bends space due to its gravitational pull. Euclid will detect subtle distortions (shearing) in the shapes of billions of galaxies caused by this effect, revealing how dark matter is distributed across the universe.
• Galaxy Clustering: By mapping the 3D distribution of galaxies, Euclid will study patterns influenced by dark matter and dark energy. Analyzing these variations in distance and over time will help scientists understand how dark energy affects the structure of the universe.

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What new insights do we expect from the Euclid mission?🔗

The Euclid mission promises to revolutionize our understanding of the cosmos by delivering:

• Dark Matter Mapping: It will determine whether dark energy is a fixed cosmological constant or something more dynamic and evolving.
• Dark Energy Mapping: Euclid will create the most detailed map yet of dark matter’s distribution across the universe.
• Cosmic Expansion History: It will provide precise measurements of how the universe has expanded over time.
• Testing Gravity: The mission will test Einstein’s theory of general relativity on vast cosmic scales, potentially revealing deviations or new physics.

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How long will the Euclid mission last, and where is it located?🔗

The Euclid mission is planned to run for 6 years. It orbits the Sun-Earth Lagrange Point 2 (L2), a stable spot about 1.5 million kilometers from Earth, where it follows a halo orbit to maintain an unobstructed view of the cosmos.

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What is an Einstein Ring? How does it form?🔗

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An Einstein Ring is a rare and fascinating astronomical event caused by gravitational lensing. It occurs when light from a distant galaxy passes near a massive object—like a foreground galaxy or black hole—and gets bent by its gravity. If the light source, the lensing object, and the observer (us) are perfectly aligned, the light forms a glowing ring around the foreground object, known as an Einstein Ring.

How It Forms:

1. Light Emission: A far-off galaxy emits light in all directions.
2. Gravitational Bending: That light encounters a massive object, such as a galaxy (e.g., NGC 6505), warps this light with its gravitational field.
3. Ring Creation: When everything lines up just right, the light curls around the foreground object, appearing to us as a bright, circular ring.

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Why are Einstein Rings important?🔗

Einstein Rings hold immense value in astronomy because they:

• Bend space-time by huge mass: By measuring how light bends, scientists can map the distribution and amount of dark matter, which can’t be observed directly.
• Magnify Distant Galaxies: The bending acts like a natural telescope, enabling us to see faint, faraway galaxies that would otherwise be too dim to see.
• Confirm Einstein’s Theory: These rings help calculate the universe’s expansion rate, offering clues about its history and future.
• Measure Cosmic Expansion: They provide stunning evidence supporting Einstein’s general relativity, showing gravity’s power to bend light on a grand scale.

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What Einstein Ring has the Euclid Telescope recently discovered?🔗

In February 2025, the Euclid Telescope spotted an Einstein Ring around the galaxy NGC 6505, located about 590 million light years away—relatively “close” in cosmic terms. While NGC 6505 was first identified in 1884, its Einstein Ring was first confirmed only recently. The ring is formed by a galaxy roughly 4.42 billion light-years away, bent by NGC 6505’s gravity. Over its 6-year mission, Euclid is expected to uncover around 100,000 strong gravitational lenses and thousands of unknown galaxies, expanding our cosmic catalog dramatically.

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