Treasure Island vs Planet Killer... The Two Faces of Asteroids [Reading Science]

[Asia Economy Reporter Kim Bong-su] The movie "Don't Look Up" depicts a scenario where a comet heading toward Earth threatens all humanity with extinction, but some cancel the destruction operation to claim the enormous resources buried within the comet.

The film portrays the two faces of asteroids wandering through space as they relate to humans. In reality, asteroids pose a deadly threat: small ones are called city killers, and slightly larger ones are civilization killers. On the other hand, composed of solid metals and rocks, they can also be "treasure islands" rich in precious metals and rare minerals.

'Treasure Island Worth $1,000 Quintillion'

On the 28th of last month, NASA announced that it will launch the spacecraft Psyche next October to explore the "treasure island" asteroid 16 Psyche, which is known to be worth an astonishing $1,000 quintillion. Originally scheduled for launch in August this year, the launch was postponed once to late September or early October due to technical issues, and finally set for October next year. NASA reported that problems arose during the integration of software developed by its Jet Propulsion Laboratory (JPL) and hardware made by the contractor MAXAR. After inspections, they concluded that adjustments could be completed by October next year to enable the launch. If launched as planned in October next year, Psyche will arrive at the asteroid 16 Psyche in August 2029 and begin exploration.

What draws attention is the value of asteroid 16 Psyche. It is estimated that 16 Psyche is the metallic core of an ancient protoplanet that lost its rocky outer layers due to collisions or other reasons, leaving only the core made of metals like iron and nickel. Scientists are excited that exploring 16 Psyche will allow them to study the internal structure of planetary cores, which lie beneath the mantles of solid planets like Earth. Economically, it is also expected to serve as a test bed for so-called space mining.

Based on observations from the Hubble Space Telescope in 2020, NASA announced that the massive asteroid 16 Psyche, approximately 200 km in diameter, is mostly composed of metal and has an estimated economic value of $1,000 quintillion. Of course, even if 16 Psyche is indeed made of iron, nickel, and other metals, transporting or mining it on Earth is currently practically impossible. Its vast quantity could also cause market collapse if mined. Scientists, however, see the extraction of water from near-Earth asteroids or the Moon for use as rocket fuel as a first step toward space mining.

Silent Killers Hidden in the Sun

The other face of asteroids is that of silent killers capable of destroying cities or entire human civilizations. In fact, the asteroid that caused the extinction of the dinosaurs 66 million years ago was about 10 km in diameter and struck the Yucat?n Peninsula in Mexico. Even smaller asteroids, those over 150 meters in diameter, can leave debris that survives atmospheric entry upon collision with Earth. If one hits a city, the shockwave would be equivalent to several nuclear bombs combined, causing mass casualties. Recently, interest has grown as astronomers have identified asteroids previously hidden by sunlight and thus unobservable. A representative example is the discovery of the 1.5 km diameter asteroid "2022 AP7," which orbits between Earth and Mercury. It is the largest potentially hazardous asteroid (PHA) discovered in the past eight years. If it were to collide with Earth, it could destroy multiple continents, leading astronomers to classify it as a "Planet Killer."

The problem is that such asteroids are extremely difficult to detect because they are obscured by sunlight, making them invisible to instruments like the Hubble Space Telescope and the James Webb Space Telescope (JWST). These sensitive devices do not observe the Sun's direction to avoid damage. A notable example is the approximately 20-meter asteroid that exploded over Chelyabinsk, Russia, in 2013. It was completely hidden by sunlight and went undetected until after the explosion, which destroyed buildings and injured about 1,500 people.

An illustration of an asteroid hidden in sunlight. Photo by Yonhap News

The only facility capable of observing asteroids hidden by sunlight, such as "2022 AP7," is the ultra-sensitive Dark Energy Camera (DEC) at the Inter-American Observatory in Chile. Even then, it can only detect asteroids in the direction of the Sun for about 10 minutes each day at sunset.