'Oumuamua

 

Don't ask me how to pronounce this. Even I have no idea.

Oumuamua is a small object estimated to be between 100 and 1000 meters (300 and 3000 feet) long, with its width and thickness both estimated between 35 and 167 meters (115 and 548 feet). It has a red color, like objects in the outer Solar System.

Oumuamua is the first interstellar object detected passing through the Solar System. It was discovered by Robert Weryk using the Pan-STARRS telescope at Haleakalā Observatory, Hawaii, on 19 October 2017, approximately 40 days after it passed its closest point to the Sun on 9 September.

The name “Oumuamua” comes from the Hawaiian language, and it means “a scout or a messenger from afar arriving first.”

Oumuamua is a mysterious interstellar object that visited our solar system in 2017. Its composition is not fully known, but scientists have proposed different hypotheses based on the available observations. Some of the possible materials that Oumuamua could be made of are:

• Ice: Oumuamua could be a chunk of frozen water or other volatiles, such as carbon dioxide or ammonia, that formed in a cold and distant region of another star system. This would explain why it showed signs of acceleration and outgassing as it approached the Sun, like a comet. However, unlike typical comets, Oumuamua did not have a visible tail or coma, which suggests that its surface was covered by a layer of dust or rock that prevented the ice from sublimating.
• Rock and metal: Oumuamua could be a fragment of a larger, rocky or metallic body, such as an asteroid or a planetesimal, that was ejected from its original system by a collision or a gravitational encounter. This would explain why it had a reddish color and a high density, similar to some asteroids in our solar system. However, this scenario does not account for the non-gravitational acceleration that Oumuamua exhibited, unless it was caused by an unknown mechanism or an external force.
• Nitrogen ice: Oumuamua could be a piece of an exoplanet similar to Pluto, rich in nitrogen ice. This would explain why it had a low albedo (reflectivity) and a high elongation (ratio between length and width), as well as the non-gravitational acceleration. Nitrogen ice is more resistant to sublimation than water ice, and it could produce jets of gas when heated by the Sun, creating a thrust that changes the object’s trajectory. However, this hypothesis requires that Oumuamua originated from a very cold and dense environment, where nitrogen ice could form and survive for long periods of time.

These are some of the most plausible explanations for Oumuamua’s composition, but none of them can fully account for all of its observed properties. Therefore, Oumuamua remains an enigma that challenges our understanding of interstellar objects and their formation processes.