Comets are one of the most fascinating and peculiar objects in space that appear in our night sky!Comets have appeared quite unpredictably in our solar system for as long as Earth has existed, but where do they originate from and where do they go when they are not in our solar system? Let’s find out!Strange icy bodies, called comets, are made up of dust and gas. Some even describe these celestial bodies as space snowballs. All comets have a nucleus that consists of frozen gases, icy lumps, and bits of dust embedded in them. As they get closer to the Sun, pieces of ice start to heat up and turn to gases due to the Sun’s radiation. This forms an atmosphere or coma around the body of the comets. It is mostly dust and gases but because the comets are usually moving at a very high speed, these gases can be blown away from the nucleus and form a long, bright tail behind the comets. The tail is one of the most characteristic features of comets, and can often be seen from a telescope or in rare cases, even with the naked eye!If you liked reading about the origin of comets, be sure to check out our other articles on where do diamonds come from? And where do nuts come from?Where do most scientists believe the majority of comets come from?Most scientists believe that most comets we observe come from the Kuiper Belt. The concept of the Kuiper Belt was suggested by Gerard Kuiper, who believed that a disk-like region of floating icy bodies exists between the orbits of Neptune and Pluto. Another place where comets may originate from is the Oort Cloud. This was proposed by Jan Oort, a Dutch astronomer. He suggested that comets originate from a spherical cloud consisting of icy celestial objects that exist far beyond the orbit of Pluto. When comets in these regions of outer space are disturbed by the gravitational interactions with other big planets, this makes them orbit into our solar system and thus, appear in our night skies.All comets are believed to have existed since the formation of the solar system 4.5 billion years ago. Within the Kuiper Belt, there are millions of comets that all orbit the Sun, but interactions between them make them form their own orbits that bring them inside the solar system. Because of the heat and radiation of the Sun, we can observe a tail behind each comet. Some comets orbit around the Sun in varying orbital periods, while others plunge straight into the Sun and are never seen again due to the extreme heat. The former category of comets that orbit around the Sun is called periodic comets. They can have orbital periods, that is, the time they take to orbit around the Sun once, from three years to millions of years.Where do short-period comets come from?Those comets that take 200 years or less to orbit the Sun are called short-period comets. These are extremely predictable as their orbit and orbital period can be calculated by astronomers. These kinds of objects are thought to originate from the disk-like region known as the Kuiper Belt, also called the Edgeworth-Kuiper Belt.Celestial objects in the Kuiper Belt region are believed to have formed just outside the solar system and thus, now make up the Kuiper Belt that exists far away between the orbits of Neptune and Pluto and maybe even beyond that. A team of astronomers discovered at least 30 cometary objects within this region, and estimate that around 200 million more could enter the inner solar system and become comets. The Kuiper Belt also consists of other small, dwarf planets, like Pluto, and is estimated to be between 30-100 astronomical units away from the Sun. For reference, one astronomical unit is considered to be the distance between Earth and the Sun.Where do asteroids and comets come from?While a comet is made up of ice, gas, and dust that vaporize due to the Sun’s heat and form a tail that appears blurred when seen through a telescope, asteroids are simply giant chunks of rock that do not usually form a tail. Both kinds of celestial bodies have different places in the outer space where they originate from. Asteroids come from the asteroid belt located between the orbits of Mars and Jupiter, and comets come from either the Kuiper Belt past the orbit of Neptune or the Oort Cloud far away from the solar system.Gravitational pulls by a large planet or other stars can cause an asteroid or comet to be pushed onto a trajectory towards the Sun. Since an asteroid is generally smaller than a comet, it does not pose a risk of impacting the Earth as catastrophically as a comet can. Both comets and asteroids are considered to be leftover in space from the giant cloud of gas and dust that formed the Sun and other planets in our solar system. Others believe that asteroids are the remnants of an older planet that broke apart in a collision and thus, formed the asteroid belt between Mars and Jupiter.Where do long-period comets come from?Long-period comets are those comets that have an orbital period between the range of 200 years to a few million years. They probably originate from the Oort Cloud, a spherical region surrounding our solar system, located at a distance of more than 100,000 astronomical units from the Sun. Thus, their orbits are too big to be calculated by astronomers and their appearance is often unpredictable.It is theorized that the objects currently in the Oort Cloud were formed much closer to the Sun when the universe was formed, but since they were smaller, they were ejected far away into outer space by the gravitational forces of other bigger objects. Those that managed to not get strewn too far away by gravity, now make up the Oort Cloud. The objects of the Oort Cloud are too distant to be seen from a telescope and are even out of reach of any space mission. Thus, its existence is still only hypothetical and without proof.Where do icy comets in the universe come from?It is estimated that nearly all other stars or planetary systems could also have enough leftover dust or debris from when the system was created, to form an Oort Cloud of their own.All icy comets in our solar system come from either the Kuiper Belt or the Oort Cloud. These were formed around 4.6 billion years ago when our planetary system was created. Some comets in the Oort Cloud are thought to belong to other stars and solar systems, which would have been pulled by the gravitational force of the Sun while passing near our system and thus, became one of the many millions of objects that reside in the distant Oort Cloud. They would then be affected by the gravitational interactions between themselves or other passing objects and be sent on a trajectory into our inner solar system and towards the Sun.Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for where do comets come from? Curious solar system fun facts for kids, then why not take a look at where do baby back ribs come from? Fun food facts for kids! Or where do beans come from? Amazing grainy facts for kids.
Comets are one of the most fascinating and peculiar objects in space that appear in our night sky!
