Source: HINDU

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Context

• Recently, scientists proposed a model to explain Arrokoth’s ice core.
• Arrokoth is one of thousands of ‘icy worlds” in the Kuiper Belt, or the outer zone of the solar system that lies beyond Neptune.
• It is the farthest object in space that has been explored by a human space-craft.

Details

Discovery and Naming

• Arrokoth was discovered on June 26, 2014, by astronomers using the Hubble Space Telescope as part of the New Horizons KBO Search (NHATS) program.
• Originally known as (486958) 2014 MU69, it was informally called Ultima Thule until its official naming.
• The name "Arrokoth" was chosen in November 2019.
• It is a Native American term meaning "sky" in the Powhatan/Algonquian language.

Characteristics

• Arrokoth is located approximately 44 astronomical units (AU) from the Sun, meaning it's about 44 times farther from the Sun than Earth.
• It is a cold, dark, and ancient relic of the early Solar System, believed to have formed over 4.5 billion years ago.
• Arrokoth is an elongated binary object composed of two lobes, informally referred to as "Ultima" and "Thule". Each lobe is roughly spherical in shape, and they are joined by a narrow neck.
• Its dimensions are approximately 36 kilometers by 20 kilometers for the larger lobe (Ultima) and 21 kilometers by 19 kilometers for the smaller lobe (Thule).
• The surface of Arrokoth is covered in reddish material, likely organic compounds that have been altered by radiation from the Sun over billions of years.

Exploration by New Horizons

• NASA's New Horizons spacecraft flew past Arrokoth on January 1, 2019, making it the farthest object ever explored by a spacecraft from Earth.
• The encounter provided scientists with valuable data about Arrokoth's composition, geology, and formation history.
• New Horizons conducted a series of observations and measurements using its suite of instruments, including cameras, spectrometers, and particle detectors.
• The spacecraft passed within approximately 3,500 kilometers of Arrokoth, capturing detailed images and collecting other scientific data during the flyby.
• The data returned by New Horizons revealed Arrokoth to be a pristine, unaltered remnant from the early Solar System, providing insights into the processes that shaped the formation of planets and other celestial bodies.

Scientific Significance

• Arrokoth belongs to a class of objects known as cold classical Kuiper Belt objects, which are believed to have formed in situ and remained relatively unchanged since the early days of the Solar System.
• Studying Arrokoth helps scientists better understand the processes of planet formation and the conditions present in the outer Solar System billions of years ago.
• Its binary nature and smooth, undisturbed surface indicate that it likely formed through a gentle merger of two smaller objects rather than through a violent collision.
• The lack of large craters or other significant geological features suggests that Arrokoth has remained largely undisturbed since its formation, providing a snapshot of the conditions present in the outer Solar System during its early history.

About Kuiper Belt

• It is a vast area of space filled with icy bodies, including dwarf planets, comets, and small rocky bodies.
• It is also called the Edgeworth-Kuiper belt, is a flat ring of small icy bodies that revolve around the Sun beyond the orbit of the planet Neptune.
• It is named after Gerard Kuiper, a Dutch-American astronomer who hypothesised the existence of such a region in the 1950s.

Characteristics:

• Location: The Kuiper Belt is located beyond the orbit of Neptune, typically starting around 30 astronomical units (AU) from the Sun and extending to about 50 AU.
• Composition: It mainly consists of icy bodies composed of frozen volatiles such as methane, ammonia, and water ice, along with rocky material.
• Density: The density of objects in the Kuiper Belt decreases with distance from the Sun.
• Orbital Dynamics: Objects in the Kuiper Belt have relatively stable orbits influenced by Neptune's gravity but are less influenced by other planets compared to the Asteroid Belt.

Formation:

• The Kuiper Belt is believed to be a remnant of the early Solar System.
• It likely formed from leftover icy planetesimals that never accreted into larger planets during the formation of the Solar System around 4.6 billion years ago.
• The gravitational influence of Neptune prevented these objects from coalescing into a planet and instead scattered them into the Kuiper Belt.

Contents:

• Dwarf Planets: Notable dwarf planets in the Kuiper Belt include Pluto, Eris, Haumea, Makemake, and others.
• Comets: Many short-period comets originate from the Kuiper Belt. These comets have highly elliptical orbits that bring them close to the Sun.
• Trans-Neptunian Objects (TNOs): These are objects orbiting the Sun beyond Neptune but not classified as planets or comets. They include various categories like cubewanos, plutinos, and scattered disk objects.

Significance:

• Understanding Solar System Formation: Studying the Kuiper Belt provides insights into the conditions and processes that led to the formation of the Solar System.
• Origin of Comets: Comets originating from the Kuiper Belt carry valuable information about the early Solar System and may have contributed water and organic compounds to Earth.
• Planetary Evolution: The dynamics of the Kuiper Belt help scientists understand the migration of planets in the early Solar System.

Exploration Efforts:

• New Horizons Mission: Launched by NASA in 2006, New Horizons provided the first close-up images and scientific data of Pluto and its moons in 2015. It continues to explore the Kuiper Belt's objects beyond Pluto.
• Telescopic Surveys: Various ground-based and space telescopes, such as the Hubble Space Telescope and the Subaru Telescope, are used to study the Kuiper Belt and discover new objects within it.

Must Read Articles:

Kuiper Belt

Sources:

HINDU

PRACTICE QUESTION Q.  Studying the Kuiper Belt provides insights into the conditions and processes that led to the formation of the Solar System.  Discuss. (150 Words)