Question

Radio telescopes are better than optical telescopes because:

• A. They can detect faint galaxies
• B. They can work in cloudy conditions
• C. They can work during day and night
• D. All of the above

Hint:

Think about how the long wavelength of radio waves lets them pass through clouds and how sunlight does not interfere with radio observations.

Answer 1

The Correct Option is D

Step 1: Radio telescopes collect radio waves, which have a much longer wavelength than the visible light used by optical telescopes.

Step 2: Long wavelength radio waves are hardly scattered or absorbed by clouds, dust and fog. So radio telescopes keep working even in cloudy weather, when an optical telescope would see nothing but a grey sky.

Step 3: Sunlight is visible light, so it blinds an optical telescope during the day. Radio noise from the Sun is comparatively weak at many radio frequencies, which lets radio telescopes observe both day and night without this problem.

Step 4: Many distant and faint galaxies emit very little visible light but strong radio emission from hot gas and charged particles, so a radio telescope can detect such galaxies that an optical telescope would miss entirely.

Step 5: Since detecting faint galaxies, working in cloudy weather and working during day and night are all genuine advantages of radio telescopes, the complete and correct choice is D, all of the above.