Why in news:-Euclid space telescope discovers new‘Einstein ring’ in nearby galaxy
Euclid Space Telescope & Einstein Rings
🔭 Euclid Space Telescope
- Launched by: European Space Agency (ESA)
- Launch Date: July 1, 2023
- Mission Purpose: To study dark matter and dark energy by mapping the large-scale structure of the universe.
- Key Instruments:
- VIS (Visible-wavelength camera): Captures high-resolution galaxy images.
- NISP (Near-infrared spectrometer and photometer): Measures galaxy distances and properties.
- Objective: To create a 3D map of the universe spanning 10 billion years of cosmic history.
🌌 Einstein Rings & Gravitational Lensing
🔄 What Are Einstein Rings?
An Einstein Ring is a rare and perfectly symmetrical form of gravitational lensing where the light from a distant galaxy is bent around a massive foreground object (like another galaxy or a black hole), forming a ring-like structure.
- Cause: Predicted by Einstein’s General Theory of Relativity, which states that massive objects warp spacetime, bending the path of light.
- Significance:
- Helps study distant galaxies that would otherwise be too faint to see.
- Reveals dark matter distribution by tracking how light bends around invisible mass.
- Provides precise measurements of galaxy masses and the expansion of the universe.
🔍 Gravitational Lensing Explained
Gravitational lensing occurs when light from a background object (like a distant galaxy) is bent by the gravity of an intervening massive object (like another galaxy or galaxy cluster).
Types of Gravitational Lensing:
- Strong Lensing – Creates highly visible effects like Einstein Rings and multiple images of the same galaxy.
- Weak Lensing – Causes subtle distortions in galaxy shapes, useful for mapping dark matter.
- Microlensing – Involves temporary brightening of a background object when a star or planet passes in front.
🌀 What is Dark Matter?
Think of dark matter like an invisible glue.
- Everything in the universe—galaxies, stars, and planets—is held together by gravity.
- But when scientists studied galaxies, they found that there wasn’t enough visible matter (like stars and gas) to produce the gravity needed to hold them together.
- There had to be something else adding extra gravity and holding galaxies in place. They called this invisible substance “dark matter.”
Key Facts About Dark Matter:
✅ It doesn’t emit light (which is why we can’t see it).
✅ It interacts only through gravity (it doesn’t collide with normal matter like atoms do).
✅ It makes up about 27% of the universe (while normal matter is only 5%).
How Do Scientists Know It Exists?
- By looking at how galaxies spin:
- If only visible matter existed, galaxies should have flown apart due to their high speeds.
- But something unseen (dark matter) is keeping them together.
- Gravitational lensing: Light from distant galaxies bends more than expected when passing massive objects, meaning extra invisible mass must be there.
⚡ What is Dark Energy?
Think of dark energy like an invisible force pushing the universe apart.
- Scientists expected that after the Big Bang, the expansion of the universe should be slowing down due to gravity.
- But instead, they found that the universe is expanding faster than ever! 🤯
- Something is acting like an anti-gravity force, pushing everything apart. This mysterious energy is called dark energy.
Key Facts About Dark Energy:
✅ It makes up about 68% of the universe (it’s the dominant force!).
✅ It causes the universe to expand at an accelerating rate.
✅ It’s even more mysterious than dark matter—scientists have no idea what it is made of!
How Do Scientists Know It Exists?
- By studying supernova explosions (dying stars), astronomers discovered that galaxies are moving away from each other faster and faster over time.
- The only way this makes sense is if there’s some unknown energy stretching space itself—dark energy.
💡 Dark Matter vs. Dark Energy: The Cosmic Tug-of-War
- Dark Matter = Pulls things together with gravity (like an invisible glue).
- Dark Energy = Pushes things apart, making the universe expand faster (like an invisible force).
They are opposites in a way, and right now, dark energy is winning—which means the universe will keep expanding forever.
❓ Do We Know What Dark Matter and Dark Energy Are Made Of?
No! That’s why they are some of the biggest mysteries in science.
- Scientists think dark matter could be a new type of particle (WIMPs or axions).
- Dark energy might be a property of space itself or even a new force of nature.
🚀 Why Does This Matter?
Understanding dark matter and dark energy will help us:
✅ Unlock the true nature of the universe.
✅ Discover new physics beyond Einstein and the Big Bang.
✅ Solve one of the biggest cosmic mysteries of all time!