Comets in the Solar System: What Are They & Where Do They Come From?
Comets have intrigued astronomy experts and the layperson alike, sparking amazement, curiosity, and wonder for millennia. The comets in the solar system travel vast elliptical paths on their journey around the Sun and have been observed and recorded for future astronomers since the 5th century and before. With the advent of modern technology, scientists have established the comet’s composition, where they are in the solar system, and their origins. Let’s take a deeper look at these interesting celestial “snowballs” and discover what their place is in the bigger astronomical picture.
For NASA scientists and astronomers, the interest in comets, based on the vital substances they are comprised of, can give clues to the early formation and conditions present when our solar system began. Relics of a turbulent time some two and a half billion years prior to the first humans, comets may have delivered water and organic materials to Earth and helped create what we know as home today.
What are comets - David Clark Swalm
What Is a Comet?
Comets are smaller solar system entities that fall into two distinct categories – the short-term variety originating in the Kuiper belt living outside Neptune’s orbit, and the long-term bodies that begin in the Oort cloud, a spheroid collection of frozen objects extending beyond the Kuiper belt.
Comets and the solar system - David Swalm
What Are Comets Made Of?
The composition of comets is a fascinating blend of materials, with the nucleus or core consisting of iced gasses, dust, rock fragments, and ice. As the comet nears the Sun, the heat and radiation cause changes in these substances from their frozen state, creating gasses, water, and dust known as the coma. As these substances trail away from the nucleus, they form a dual, multi million-mile tail, one part consisting of dust and appearing white, the other formed from ions, with a blue tint, and trailing straight away from the Sun.
Where Are Comets Found in the Solar System?
Most of their existence is spent long distances from the Sun in the deepest realms of the outer solar system, like the Kuiper belt and the Oort cloud extending to the edge of the solar system 100,000 astronomical units from the Sun. After making their amazing journey around the Sun (closest point or perihelion), they continue their orbit, returning home to the far edges of the solar system (furthest point or aphelion). So, even though humans seeing them with the naked eye, through telescopes, or from data gathered by spacecrafts seems rare, it’s safe to say that comets are everywhere in our solar system.
How Many Comets Are in the Solar System?
Professional astronomers calculate, based on the relatively short life of comets (10,000 years) and the endless re-supplying, that the number of comets in the solar system is in the billions. Some calculations using the Oort cloud’s size estimate the number could be a trillion. Although the number of known/named comets is just 3,743 currently, improvements in spacecraft and exploration should continue to increase this number. NASA’s Hubble Space Telescope alone is sending back comet data regularly, including pictures of the largest comet nucleus ever observed, in April 2022.
How Fast Do Comets Travel?
Depending on their distance from the Sun, comets can speed through space at 2,000 miles an hour and increase speed as their nucleus loses mass nearing the Sun to 100,000 miles an hour. This wide variance in speed is determined by orbital shape and the aforementioned distance from the Sun at any point and time. Scientists use physics computation like Kepler’s law to calculate the speed of an object on an elliptical path, but to put in layman’s terms, along with position, the width of the orbital ellipse will increase or decrease speed – the narrower, the more speed will increase.
How Does a Comet Get Its Name?
The conventional way of naming comets is a practical one – using the names of their discoverers or the facility associated with the observance, the former being the most widely used with famous comets. A more current and scientific system has also been implemented to define the nature and year of comets using alpha-numeric tags such as 1P/1682 Q1 assigned to Halley’s comet. 1P indicates it is the first periodic comet, 1682 is the year, and Q1 indicates the time of year.
Famous Comets in the Solar System
Halley’s Comet – Discovered by observation in prehistoric times, the comet got its name from the first predictor of its cycle Edmond Halley, a friend of Sir Isaac Newton.
Hale Bopp – Known formally as C/1995 01, the comet is named for two separate observers: A. Hale, and T. Bopp.
Comet Hyakutake – Discovered in 1996, also known as the “Great Comet,” the comet is named for astronomy enthusiast Yuji Hyakutake.
Comet Swift-Tuttle – Discovered in 1862, the comet is named for astronomers L. Swift and H. Tuttle.
Wild 2 – Known as 81P/Wild and discovered in 1978, Wild 2 was thought to be 2.5 billion years older than humankind. It is named for observer Paul Wild.
Summary
The comets in our solar system are one of many exciting areas that astronomy covers. Along with asteroids and many other small solar system bodies like Pluto, Charon, and the objects of the Kuiper belt and Oort cloud, comets give experts and novices alike a glimpse into the forming and evolving of our tiny piece of the Cosmos.
I sincerely hope that you do not stop here, but let this article be the jumping-off point for a long journey to understanding the true depths of this massive frontier.
The science of astronomy, using tools such as math, chemistry, and many other sciences, should be encouraged for everyone – especially our young minds that will shape the future and grow our collective intelligence.
