Sonic Boom

5. Sonic Boom

In News: Researchers have successfully used seismometers to detect sonic booms produced by space debris re-entering Earth’s atmosphere, highlighting cross-linkages between atmospheric physics and earth sciences.

What is a Sonic Boom?

• A sonic boom is a loud, thunder-like sound produced when an object travels faster than the speed of sound (Mach 1).
• Commonly associated with supersonic aircraft, missiles, and re-entering space debris.

How is a Sonic Boom Formed?

1. As an object moves at supersonic speed, it compresses air molecules faster than sound waves can propagate.
2. This creates shock waves that merge into a cone-shaped wave (Mach cone).
3. When this shock wave reaches the ground, it is heard as a sonic boom.

Key Characteristics

1. Sonic booms release large amounts of acoustic energy.
2. The sound is not continuous but heard as a sudden explosive noise.
3. Long aircraft can produce double booms:

• One from the nose (leading edge)
• One from the tail (trailing edge)

Factors Affecting Intensity

The loudness and impact depend on:

1. Altitude of the object (higher altitude - weaker boom)
2. Size and weight of the object
3. Shape and length of the aircraft
4. Flight maneuvers
5. Atmospheric conditions:

oTemperature

oAir pressure

oWind speed and direction

6Larger and heavier objects displace more air - stronger shock waves.

Visible Effects

1. Sometimes a cloud or cone-shaped vapor is seen around the aircraft.
2. This is not the sound, but condensed water vapour formed due to rapid pressure changes caused by shock waves.

Impacts

1. Can shatter glass windows
2. Cause structural vibrations
3. Generally low risk to human life, but repeated exposure may cause disturbance

Scientific Significance

1. Detection using seismometers shows that sonic booms can be recorded as ground vibrations.
2. Helps in:

• Tracking re-entering space debris
• Improving aerospace safety
• Understanding atmospheric–seismic interactions