Near-Earth Objects and Planetary Defense

A series of vocabulary flashcards related to Near-Earth Objects and planetary defense, covering key terms, definitions, and concepts necessary for understanding potential asteroid and comet threats to Earth.

Near-Earth Objects (NEOs)

Asteroids or comets whose orbits bring them within approximately 30 million miles of Earth’s orbit.

Near-Earth Asteroids (NEAs)

The most common type of Near-Earth Objects.

Near-Earth Comets (NECs)

Fewer and usually faster Near-Earth Objects that are less predictable.

Small NEOs

NEOs that can burn up in the atmosphere, such as fireballs, and are usually harmless.

Medium NEOs (10–140 m)

NEOs that can explode in the atmosphere or cause injuries and damage, such as the Chelyabinsk event in 2013.

Large NEOs (>140 m)

NEOs that can cause regional destruction and major infrastructure damage.

Very Large NEOs (>1 km)

NEOs that can cause global climate effects and mass extinction, exemplified by the Chicxulub asteroid.

Planetary defense

All actions taken to detect, assess, and respond to asteroid and comet threats.

Detection

The first core function of planetary defense, involving finding NEOs using telescopes.

Characterization

The process of determining the orbit, size, shape, mass, composition, and rotation of NEOs.

Mitigation

The response strategies to a predicted impact, including deflection and emergency planning.

DART mission (2022)

A mission that successfully changed the orbit of an asteroid, demonstrating deflection technology.

Impact Frequency + Severity

The probability of different sizes of NEO impacts and their potential consequences.

Planetary Defense Cycle

A continuous loop involving assessing threats, detecting and tracking NEOs, characterizing them, planning, coordinating, and mitigating.

Chelyabinsk event (2013)

An airburst explosion caused by a small asteroid that resulted in around 1,600 injuries.

International Cooperation

Collaboration necessary in planetary defense as asteroids do not respect national borders.

Key Statistics on NEOs

Data regarding the estimated number of NEOs and the percentage detected for various sizes.