Chapter 22

IA, THE COMETS: MESSENGERS OF THE UNIVERSE

“Witnesses of the cosmic origin ”

 “ Ice and Light Commissioners ”

AI, GENERALITIES OF ASTRONOMY

By: José Saul Velásquez Restrepo

Astronomy is the science that studies the celestial bodies of the universe, such as stars, planets, satellites, comets, asteroids, galaxies, and everything that exists outside the Earth's atmosphere. It also analyzes phenomena that occur in space, such as eclipses, supernovae, and orbital motions.

Astronomy is one of humanity's oldest sciences. Since ancient times, humans have looked to the sky in search of answers about their origins, the weather, the seasons, and the universe around them. Today, astronomy remains a powerful tool for understanding the vastness of the cosmos and our position within it.

Main branches of astronomy:

Observational astronomy : based on directly observing stars using telescopes, radio telescopes and space probes.

Theoretical astronomy:  uses mathematical and physical models to explain the origin, evolution and behavior of the universe.}

Astrophysics:  applies laws of physics to celestial bodies to understand their structure, composition, and energy.

Cosmology:  studies the universe as a whole: its origin (Big Bang), evolution and possible destiny.

Astrobiology:  seeks to understand the origin of life in the universe and the possibilities of life on other planets.

Instruments used in astronomy:  optical telescopes that capture visible light from stars.

Radio telescopes: detect radio waves coming from space.

Satellites and space probes: allow us to study the universe without interference from the Earth's atmosphere.

Computers and simulation software: essential for processing and analyzing large amounts of astronomical data.

Great contributions of astronomy

He taught us that the Earth revolves around the Sun.

We discovered galaxies beyond the Milky Way.

We understood the nature of eclipses, seasons, and celestial movements.

We detect planets outside the solar system (exoplanets).

He contributed to the development of the calendar, navigation, and space technology.

Cultural and scientific importance:  Astronomy not only has scientific value, but also philosophical and spiritual value. It invites us to reflect on our place in the universe, on the fragility of the planet, and on the need to care for it. It has also inspired mythologies, religions, literature, and art throughout history.

Astronomical curiosities:  a star can be millions of times larger than the Sun!

There are more stars in the universe than grains of sand on all the beaches on Earth.

Sunlight takes approximately 8 minutes to reach Earth.

The James Webb Space Telescope allows us to see into the past, observing light that emerged from galaxies more than 13 billion years ago.

Conclusion: Astronomy connects us with the vast, the unknown, and the human desire to learn. Thanks to this science, we know more about the universe, our solar system, and the hidden beauty that dwells in the depths of space.

Here's a carousel of high-quality images to illustrate your article on comets:

Comet Hale-Bopp with its dust and gas tails clearly visible.  Esahubble.org+5 Esahubble.org+ 5 Esahubble.org+5 The New Yorker+13 Apod.nasa.gov+13 Sky & Telescope+13

Comet NEOWISE captured during its 2020 passage, showing gas and ice structures.  Esahubble.org+8 Esahubble.org+ 8 Axios+8

Detail of the gas and dust tail in a cometary coma (representative generic image)

Close-up view of Comet Hale-Bopp's tail in a starry sky  Wikipedia+5skyatnightmagazine.com +5Reddit+5 Reddit

COMET OVERVIEW:  Studying them allows us to better understand the evolution of celestial bodies, which are made of  ice, dust, and rocks and orbit the Sun along very elongated trajectories. They originated more than  4.6 billion years ago and are considered  remnants of the formation of the solar system .

Unlike planets, comets have  very eccentric orbits , meaning they can pass close to the Sun and then travel far away, even past Pluto.

Main characteristics: nucleus : solid central part, composed of ice and rock.  Coma : cloud of gas and dust that surrounds the nucleus when the comet approaches the Sun.  Tail : formed by particles that are released by the action of the Sun's heat. It can reach millions of kilometers and always points away from the Sun.  Ion tail : generated by gases that are ionized by the Sun and that point in the opposite direction.

Classification of comets according to their orbital period:

Short period : they take less than 200 years to orbit the Sun. Example: Halley's Comet.

Long period : They can take thousands or even millions of years to complete their orbit. They originate from distant regions such as the  Oort cloud .

Scientific importance:  They are  fossil remains  of the early solar system. They may contain  complex organic molecules , which has led to speculation that they may have contributed to the origin of life on Earth.

Observation from Earth:  When a comet passes close to the Sun and the Earth, it can be visible to the naked eye, becoming a  striking astronomical spectacle .

A comet is a small celestial body composed primarily of  ice, dust, and rocks that orbits the Sun. They are often called  the "dirty snowballs"  of the solar system. As they approach the Sun, they heat up and release gases and particles, creating a  glowing tail  that can extend for millions of kilometers.

WHERE DO COMETS ORIGINATE?

Most come from two regions of deep space:

The Kuiper Belt : beyond Neptune, it hosts short-period comets (less than 200 years).

The Oort Cloud : A huge hypothetical sphere surrounding the solar system. Long-period comets (taking thousands of years to orbit the Sun) originate from it.

WHY ARE COMETS IMPORTANT?

Messengers from the past : Comets contain primitive materials dating back to the origin of the solar system, more than 4.6 billion years ago.

Keys to life : It is believed that they may have brought water and organic compounds to early Earth.

Spectacular phenomena : when they pass close to Earth, they offer an unforgettable spectacle for humanity.

FAMOUS COMETS:

Halley's Comet : Visible from Earth every 76 years. Its return is expected in 2061.

Hale-Bopp Comet (1997) : one of the brightest of the 20th century.

Comet Neowise (2020) : visible to the naked eye in many parts of the world.

Comet Shoemaker-Levy 9 (1994) : collided with Jupiter, providing valuable information to science.

HOW IS A COMET OBSERVED?

With the naked eye in dark, clear skies.

Its structure can be better appreciated with binoculars or telescopes.

There are apps and websites that tell you when and where a comet can be seen.

Tip : Staying away from light pollution is key to enjoying the show.

INTERESTING FACTS ABOUT COMETS

The word  "comet"  comes from the Greek  kometes , meaning "hair", due to its appearance.

In ancient times, comets were seen as  omens of great events .

Some comets leave trails of dust that generate  meteor showers , such as the Perseids.

The true function of comets is not entirely defined as "purposeful instruments" in the universe, but from a scientific, cosmological, and biological perspective, comets fulfill several important and fascinating roles:

Witnesses to the origin of the solar system:  Comets are primitive remnants from the formation of the solar system, some 4.6 billion years ago. They are composed of ice, dust, and organic compounds, materials that did not consolidate into planets.

Function: They preserve intact information about the original conditions of the solar system.
Scientific interest:  They are like time capsules that allow us to study what the "raw material" of the early universe was like.

Distributors of water and organic molecules:  Many theories hold that comets brought water and compounds essential for life to early Earth.

Function: Possible vehicles of life (panspermia hypothesis).
Evidence: Complex organic molecules, such as amino acids, have been found in comets.

Participation in planetary evolution: Comet impacts on Earth and other planets have altered their surfaces, climate, and even atmospheric chemistry.

Function: agents of transformation of the planetary environment.
Example: Comet Shoemaker-Levy 9 impacted Jupiter in 1994, releasing enormous energy and allowing its atmosphere to be studied.

Key objects of astronomical study:  thanks to them, astronomers have made progress in multiple fields: the composition of space, gravity, orbital dynamics, etc.

Function: natural laboratories on the move.
A tool for discovering new regions of the solar system (such as the Oort Cloud or the Kuiper Belt).

Sources of cultural and philosophical inspiration:  throughout history, comets have been interpreted as omens, divine signs, or heavenly messengers, leaving their mark on mythology, literature, and art.

Symbolic function: they represent the unpredictable, change or cosmic wonder.

In short: comets are not just spectacular celestial phenomena; they are key pieces in the cosmic puzzle. Their most profound function is to remind us of our origins and the possibility of life beyond Earth.

CONCLUSION:  Comets are solitary travelers who visit us from the depths of space. They bring with them secrets about the origins of the universe and remind us of the wonder of our solar system. Thanks to technology, we can now observe them, study them, and marvel at their beauty.

Recent comets observed from Earth:

C/2024 G3 (ATLAS) — “Great Comet of 2025”

It reached perihelion on  January 13, 2025 , with a maximum brightness near  magnitude –3.8 , comparable to Venus. It was visible without a telescope under clear skies, especially from the Southern Hemisphere near perihelion and from the Northern Hemisphere thereafter.  The Sun+11BEMAN ASTROPHOTOGRAPHY+11National Geographic+11 .

C/2025 F2 (SWAN) (also known as SWAN25F):  Discovered in March 2025. It reached magnitude around  8.1–8.3 , visible with binoculars or a telescope.

Its brightness increased rapidly between April and May, developing a thin tail; it may have undergone fragmentation before perihelion  Wikipedia infobae .

29P/Schwassmann‑Wachmann 1:  A periodic comet with highly variable activity and frequent outbursts of brightness. It reached magnitude ~11–12 in March/April 2025 and was observed with large telescopes.  Tiempo.com | Meteored Cometography Stargazers Club WA .

C/2022 E2 (ATLAS) and 21P/Giacobini-Zinner:  the former was visible in telescopes in February 2025; the latter, a 6.6-year periodic comet, reached perihelion on  March 29, 2025 , at moderate brightness and possibly visible to the naked eye under excellent conditions.  WIRED+15Tiempo.com | Meteored+15El Tiempo+15 .

Upcoming comets visible from Earth:

C/2025 K1 (ATLAS):  perihelion:  October 8, 2025. Estimated brightness at  mag 5.2 , potentially visible with binoculars.

Closest approach:  November 24, 2025  (0.40 AU), brightness ~9.7. Visibility in both hemispheres; most visible from northern latitudes during perihelion and from the south at other times.  Tiempo.com | Meteored+4Star Walk+4BEMAN ASTROPHOTOGRAPHY+4 .

C/2025 A6 (Lemmon); perihelion:  November 8, 2025 ; closest approach to Earth:  October 21. Estimated brightness near  mag 8 , observable with binoculars, possibly best from the Northern Hemisphere  . Star Walk BEMAN ASTROPHOTOGRAPHY .

210P/Christensen:  perihelion:  November 22, 2025 , closest approach:  November 8 .

Approximate brightness of  mag 8 , visible with small telescopes or large binoculars, especially from the northern hemisphere  Cometografía+12Tiempo.com | Meteored+12BEMAN ASTROPHOTOGRAPHY+12 .

24P/Schaumasse:  appears in early  January 2026  (perihelion: January 8, visibility close to the cluster M44).

Estimated brightness ~ mag 8–8.5 , visible with binoculars from both hemispheres  BEMAN ASTROPHOTOGRAPHY+1Star Walk+1 .

C/2024 E1 (Wierzchoś):  perihelion:  January 20, 2026. Maximum brightness expected at  mag ~5.5 .

Visibility: Northern Hemisphere before perihelion; then best from the south. May be visible with binoculars under dark skies.  BEMAN ASTROPHOTOGRAPHY+1Tiempo.com | Meteored+1 .

3I/ATLAS:  Discovered on  July 1, 2025 , it originated in interstellar space and is possibly much older than the solar system. It will reach perihelion on  October 30, 2025 , and will be closest to Earth in  December 2025 .

Although it will not be visible to the naked eye, it is expected to be visible with telescopes or binoculars in  late 2025 and early 2026  Cadena SER+1The Sun+1 Live Science+1National Geographic+1 Tiempo.com | Meteored+1El Tiempo+1 .

Comparative summary

AI Opinion: Author: José Saul Velásquez Restrepo

Strengths: Clarity and pedagogical structure:

The organization of the text into sections (What is a comet? Why are they important? etc.) is well-suited to readers of different levels, from amateurs to students.

Rigorous but accessible content:

You explain technical concepts like the nucleus, the comma, and tails without resorting to overly academic language. Very well-balanced.

Update and relevance:

The inclusion of the most recent comets such as  C/2024 G3 (ATLAS)  and  C/2025 K1 (ATLAS)  adds unique value and shows that you are up to date with contemporary astronomy.

Integration of history and culture:  References such as the etymology of the word “comet” or its symbolism as omens are enriching details that link science and culture.

Call to wonder:

The conclusion and some phrases (“lonely travelers,” “messengers from the past”) have a poetic charge that connects emotionally with the reader.

Suggestions for improvement:

Embed images directly:

While photo references are fine, it would be ideal to visually insert them into the document with a caption, such as:
Comet Hale-Bopp photographed from Earth. Source: NASA/APOD

If you need it, I can help you prepare a PDF or blog version of the article with embedded images.

Add links or resources for the curious reader:

Sites like  Heavens-Above  or  Sky & Telescope  could be linked to invite readers to explore further.

Possible alternative title:

“ Comets: Witnesses of Cosmic Origin ” or “ Messengers of Ice and Light ” may be more literary or metaphorical alternative titles, if you are looking to broaden the scope.

Editorial conclusion:  This article is a solid work of astronomy outreach. It not only conveys scientific information with clarity and depth, but also sparks curiosity and wonder. With some formatting improvements (images and active links), it is ready for publication in an educational medium, astronomy blog, or even a popular science journal.