International Asteroid Day 2023: What are Asteroids? How do Asteroids get to Earth?

As the calendar turns to June 30th, 2023, people across the globe come together to commemorate International Asteroid Day. Also referred to as World Asteroid Day 2023, this event serves as a significant platform for boosting awareness and knowledge about asteroids, their formation, and the potential threat they pose to our planet.

What are Asteroids?

When we consider the question, "What are asteroids?" we delve into the earliest epochs of our solar system. Predominantly found between Mars and Jupiter, asteroids are the rocky remnants left over from the early solar system formation about 4.6 billion years ago.

Sometimes known as minor planets, these bodies give us insights into the conditions that prevailed during the infancy of our solar system. As we celebrate International Asteroid Day 2023, NASA's database records over 1,298,255 known asteroids.

These celestial bodies vary greatly in size, ranging from Vesta—the largest known asteroid with about 329 miles (530 kilometers) in diameter—to bodies less than 33 feet (10 meters) across. Intriguingly, despite their vast numbers, the total mass of all asteroids combined is less than that of Earth's Moon.

How Asteroids are Made: The Composition of Asteroids

Asteroids are broadly classified into three groups based on their composition: C-, S-, and M-types. The most common C-type (chondrite) asteroids likely consist of clay and silicate rocks.

S-types, or "stony" asteroids, are made up of silicate materials and nickel-iron, while M-types are metallic, primarily composed of nickel-iron.

These compositional distinctions tell us about their origin and the varied distances at which they formed from the Sun.

Also watch: World Asteroid Day 2023: Theme, History, Why International Asteroid Day is Celebrated?

Asteroids Approaching Earth: Near-Earth Objects

One of the most fascinating—and unsettling—aspects of asteroids is their potential to collide with our planet.

While orbiting the Sun, the paths of asteroids can be disrupted by the gravitational forces of planets, particularly Jupiter. Such interactions can eject asteroids from the main belt, transforming them into Near-Earth Objects (NEOs).

NEOs are asteroids that have orbits passing close by Earth's path, making them potential impact threats. Throughout Earth's history, several significant asteroid impacts have occurred.

The most notable is perhaps the Chicxulub impact event, which occurred in what is now Mexico and is widely believed to have caused the extinction of the dinosaurs.

On Asteroid Day 2023, special attention is given to these NEOs. Scientists continuously monitor these celestial bodies, using radar technology to detect, track, and study potential impact threats.

By deepening our understanding of these cosmic relics, we enhance our preparedness to deal with potential asteroid dangers, ensuring the safety of our planet for future generations.