Article Outline: World’s Largest Telescopes
- Date: 10th December 2025
- Title: Research with the World’s Largest Telescopes
- Speaker: Dr Katharine Johnston
Structure (Condensed ~450 words)
1. Hook/Introduction
- First black hole image (2019)
- Answer: Earth-sized telescope
2. Why Size Matters
- Resolution = lambda/D
- Sensitivity: bigger bucket, more photons
- Radio telescopes larger due to longer wavelengths
3. Seeing Through Dust
- Dust blocks visible light like fog
- Longer wavelengths penetrate (Wi-Fi analogy)
- Submillimetre sky as “treasure trove”
4. Interferometry: Combining Telescopes
- ALMA: 66 antennas at 5,000m
- Resolution from baseline, not dish size
- Earth rotation fills effective aperture
5. The Event Horizon Telescope
- Global baselines: 12,000 km effective diameter
- 20 microarcseconds resolution
- Data shipped on hard drives
6. Seeing Black Holes
- M87 (2019), Sagittarius A* (2022)
- Tests of general relativity: shadows match predictions
7. Take-Home Message
- Larger = sharper and more sensitive
- Longer wavelengths see through dust
- Interferometry creates planet-sized instruments
External Sources to Include
- Reference: ESO website on VLT/ALMA specifications
- Quote: Scientific statement on interferometry capabilities
Context Points
- Societal: Understanding cosmic origins, technology development
- Research: Black hole physics, star formation, testing general relativity
Style Notes
- Use relatable comparisons (Wi-Fi through walls)
- Explain interferometry simply (combining signals, not complex physics)
- Highlight the human achievement (telescope the size of Earth)
- Include specific results (black hole images)