Asteroids Size Comparison

This is an impressive comparison of asteroid sizes. Some of the asteroid names out there are mentioned and compared. See enormous sizes compared to New York City and different towers and skyscrapers.

We know the planets in the solar system. They are planets, such as: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. There also could be certain undiscovered planets.

Asteroids are minor planets, especially of the inner Solar System. Larger asteroids have also been labeled so-called planetoids. These terms have historically been applied to any astronomical object orbiting the Sun that did not resolve into a disc in a telescope and was not observed to have characteristics of an active comet such as a certain tail.

Minor planets in the outer Solar System were discovered that were found to have interesting volatile-rich surfaces similar to comets. These came to be distinguished from the objects found in the main asteroid belt. The term "asteroid" certainly usually refers to the minor planets of the inner Solar System, including those co-orbital with Jupiter.

Asteroids are different from comets and meteoroids.

For comets, there is a difference of composition. Asteroids are mainly composed of mineral and rock. Comets are primarily composed of dust and ice. To add to that, asteroids formed closer to the sun, preventing the development of cometary ice.

For meteoroids, it is mainly a size difference. Meteoroids have a diameter of one meter or less. Asteroids have a diameter of greater than one meter. To add to that, meteoroids can be composed of either cometary or asteroidal materials.

The history of known asteroids is interesting. The first asteroid to be discovered was Ceres. It was, at first, considered to be a new planet. This was followed by the discovery of other similar bodies. The equipment of the time was not very good at viewing these objects. They appeared to be points of light like stars. They showed little or no planetary disc. However, they were distinguishable from stars due to their apparent motions. Because of this, astronomer Sir William Herschel proposed the term "asteroid." In Greek, it would be: ἀστεροειδής. This means 'star-like, star-shaped', and derived from the Ancient Greek ἀστήρ (star, planet). In the early second half of the 19th century, the terms "asteroid" and "planet" (not always qualified as "minor") were still often used interchangeably.

Here is an interesting overview of the discovery timeline:

10 asteroids discovered by 1849:

01 - Ceres - 1801
02 - Pallas - 1802
03 - Juno - 1804
04 - Vesta - 1807
05 - Astraea - 1845

(in 1846, planet Neptune was discovered)

06 Hebe - July 1847
07 Iris - August 1847
08 Flora - October 1847
09 Metis - 25 April 1848
10 Hygiea - 12 April 1849

Asteroids discovered by 1868: 100

Asteroids discovered by 1921: 1,000

Asteroids discovered by 1989: 10,000

Asteroids discovered by 2005: 100,000

Asteroids discovered by 2020: 1,000,000