Comets are some of the coolest things in our solar system. They’re like giant snowballs made of ice, rock, and dust that come from way out beyond Neptune. When they get close to the sun, they heat up and form a glowing cloud called a coma and a long tail that always points away from the sun. Recently, a comet named C/2022 E3 (ZTF) was discovered, and it’s making a close approach to Earth for the first time in 50,000 years!
Whenever a new comet is spotted, people often worry if it might crash into Earth. But don’t worry! This green comet won’t hit us. At its closest, it will still be 26 million miles away. If it keeps getting brighter, we might even see it without a telescope under dark skies.
We find hundreds of comets every year, but most are too dim to see without special equipment. This comet, however, is on a unique path around the sun and is bright enough to catch our attention. As it gets closer to the sun, the ice on it turns into gas, which is why it glows. The green color comes from a chemical called cyanogen, which is poisonous. We first saw cyanogen in a comet back in 1910 with Halley’s Comet.
This comet comes from a place called the Oort Cloud, a huge area filled with icy bodies far beyond the planets. The Oort Cloud was predicted by a Dutch astronomer named Jan Oort. After passing the sun, this comet will be best seen in the northern sky near the North Star.
Light from the sun takes over eight minutes to reach Earth, but it takes much longer to reach the Oort Cloud. There might be hundreds of billions or even trillions of icy objects there. Sometimes, one of these icy bodies gets knocked off course and starts a long journey toward the sun. Most long-period comets, like this one, are seen only once in recorded history because they take so long to orbit the sun.
The last time this green comet was near Earth was about 50,000 years ago, and it might not return for another million years. Some comets never come close to the sun at all. There are also short-period comets, like Halley’s Comet, which appears every 75 to 76 years. By studying comets, scientists hope to learn more about how planets formed and how life might have started on Earth.
We know less about comets than we do about planets. Comets are part of three main areas of knowledge: well-studied planets, mysterious but interesting giant planets, and the almost unstudied comets. The Oort Cloud is a spherical swarm of comets surrounding the sun, much larger than the area where the planets are. The Kuiper Belt, another region, is closer and is the source of short-period comets.
While asteroid impacts are more common, comets can be larger and more dangerous. That’s why scientists keep a close eye on them. According to NASA, no comet or asteroid is currently on a collision course with Earth, so there’s no need to worry about a major impact anytime soon.
So, let’s enjoy the amazing sight of this green comet. It’s a rare chance to see something truly special in the sky!
Gather materials like cotton balls, glitter, and a small ball to create your own model of a comet. Use the cotton balls to represent the coma and the glitter to mimic the tail. This hands-on activity will help you understand the structure of a comet and how it changes as it approaches the sun.
Keep a journal to record your observations of the night sky over a month. Note any changes in the visibility of stars and planets, and if possible, try to spot the green comet. This will help you learn about the movement of celestial bodies and the conditions needed to observe them.
Conduct research on the Oort Cloud and create a presentation to share with the class. Include information on its location, composition, and significance in the solar system. This will deepen your understanding of where comets originate and their journey through space.
Explore different cultures’ myths and historical accounts of comets. Write a short essay or create a storyboard about how comets were perceived in ancient times and their impact on human history. This activity will connect scientific concepts with cultural perspectives.
Use a computer simulation or an online tool to model the orbit of a comet around the sun. Experiment with different variables such as speed and trajectory to see how they affect the comet’s path. This will help you understand the dynamics of comet orbits and their long journeys through the solar system.
**Sanitized Transcript:**
[Music] Comets are some of the most fascinating objects in our solar system. These icy bodies are made up of rock and dust and are believed to have formed in the outer reaches of the solar system, beyond the orbit of Neptune. As they approach the sun, they develop a bright coma or fuzzy atmosphere and a long tail that points away from the sun. A recently discovered comet named C/2022 E3 (ZTF) is set to make a close approach to Earth for the first time in 50,000 years.
Whenever a new comet is discovered, it is natural for people to wonder about the potential dangers it could pose to human life on Earth. Where does this comet come from? Are there any potential hazards associated with it, such as a collision with Earth or interference with satellite and space missions? Comets are notoriously unpredictable, but there is no threat of this green comet crashing into Earth, as it will be 26 million miles away from us at its closest approach. If it continues its current trend in brightness, it could become visible to the unaided eye under dark skies.
So, what do we know about this comet? We discover hundreds of comets a year, and in some cases, depending on which telescopes are tasked to it, it could even be thousands. This comet was discovered last year, so the act of discovering a comet is not itself extraordinary. Most of those comets never get bright enough to be visible to the unaided eye. They are moving too quickly, and you have to know where to look today versus yesterday, which will be different from where you have to look tomorrow.
This one, in particular, based on its trajectory and how bright it has been for the past few months, is headed on a deep loop orbit around the sun. As it descends towards the sun, the heat will sublimate the ice. Why is it green? We can spectroscopically analyze the comet by putting the light through a prism, revealing the chemistry that’s going on. We know that there are a couple of ways to get green, one of which is from the molecule cyanogen, which is poisonous. The first time we detected cyanogen in a comet was in Halley’s Comet in 1910.
This comet comes to us from the Oort Cloud, which has only ever been theoretically predicted due to the existence of comets like this one. It was predicted to be there by Dutch astronomer Jan Oort. This comet has already passed the sun, reaching its intrinsic brightness, and is now working its way back out of the solar system. After it dips around the sun, it will be best viewed in our northern skies as it passes by the North Star.
When light leaves the sun, it takes a little over eight minutes to reach Earth, but it will be another 8 to 28 days before the same sunlight reaches the inner edge of the Oort Cloud, and perhaps as much as a year and a half before the sunlight passes around the Oort Cloud’s outer edge. There may be hundreds of billions, even trillions, of icy bodies in the Oort Cloud. Occasionally, something disturbs the orbit of one of these icy worlds, causing it to begin a long fall towards our sun. Most known long-period comets have been seen only once in recorded history because their orbital periods are so long.
The last time this green comet was visible from Earth was approximately 50,000 years ago, and it is predicted that it will not be seen again in the inner solar system for at least a million years. However, it could also leave the solar system completely. There are also comets that have never ventured close to the sun in the billions of years since they formed.
Another type of comet includes periodic comets, which have an orbital period of less than 200 years. Perhaps the most famous short-period comet is Halley’s Comet, named after astronomer and mathematician Edmund Halley. This comet is visible from Earth every 75 to 76 years and was observed by Halley in 1682, who correctly predicted its return in 1758. By studying comets, scientists hope to learn how planets formed and even how life may have evolved on Earth.
We know much less about comets than we do about the giant planets, and we know much less about the giant planets than we do about the terrestrial planets. We have three domains of knowledge: the first is well-studied, the second is mysterious but interesting, and the third, comets, are almost unstudied. We are still discovering major new populations of bodies containing comets.
The first to be discovered was the Oort Cloud, a spherical swarm of comets surrounding the sun, about 100,000 astronomical units across. The distance to Neptune is about 30 astronomical units, so this is much larger than the size of the planetary region of the solar system. The orbit of Neptune would be completely invisible on this plot; it’s so small. This swarm of comets is inferred from the long-period comets that seem to fall into the solar system randomly from all directions, with equal numbers coming in from the northern and southern hemispheres.
There are probably almost a trillion comets in the Oort Cloud. While comets individually are small, perhaps a few miles across, their collective mass is significant, and their distribution is important for understanding the solar system. The Kuiper Belt is much smaller, starting at the orbit of Neptune and extending outward. It is a disc-like region and is the source of what we call short-period comets, which do not fall in from the Oort Cloud but instead from the Kuiper Belt.
Although asteroid impacts are far more frequent than comet impacts, some comets crossing Earth’s orbit are considerably larger than any known near-Earth asteroids. Thus, the largest and most devastating impacts on Earth are likely to be from comets. This is why scientists and organizations closely monitor and track these objects to set up plans and strategies to mitigate any potential hazards.
According to NASA, there is no known comet or asteroid currently on a collision course with Earth, so the probability of a major collision is quite small. In fact, as best we can tell, no large object is likely to strike Earth anytime in the next several hundred years. So, we can relax and enjoy the unique astronomical phenomenon of the green comet, as it is a once-in-a-lifetime opportunity to witness this celestial event in human history.
Comet – A celestial object made of ice, dust, and rocky particles that orbits the Sun, often developing a bright tail when near the Sun. – Halley’s Comet is one of the most famous comets, visible from Earth every 76 years.
Earth – The third planet from the Sun in our solar system, which is home to all known life. – Earth is unique because it has liquid water on its surface and supports a diverse range of life forms.
Oort Cloud – A theoretical cloud of icy bodies that is believed to surround the solar system at a great distance, thought to be the source of long-period comets. – Scientists believe that the Oort Cloud is a vast, distant region that contains billions of icy objects.
Cloud – A visible mass of condensed water vapor floating in the atmosphere, or in astronomy, a collection of gas and dust in space. – The Orion Nebula is a massive cloud of gas and dust where new stars are being formed.
Sun – The star at the center of our solar system, which provides light and heat to Earth. – The Sun’s energy is crucial for life on Earth, driving weather patterns and enabling photosynthesis in plants.
Ice – Frozen water or other frozen substances found in space, often on comets, moons, and planets. – The polar ice caps on Mars suggest that the planet may have once had liquid water.
Gas – A state of matter consisting of particles that have neither a defined volume nor shape, often found in stars and nebulae. – The Sun is composed mostly of hydrogen and helium gas, which fuels its nuclear reactions.
Cyanogen – A poisonous gas with a faint almond-like odor, sometimes found in the tails of comets. – When a comet approaches the Sun, cyanogen gas can be released, contributing to the comet’s glowing tail.
Orbit – The curved path of a celestial object or spacecraft around a star, planet, or moon. – Earth’s orbit around the Sun takes approximately 365.25 days to complete, resulting in our calendar year.
Sky – The expanse of air over the Earth, where celestial bodies like stars, planets, and the Sun can be observed. – On a clear night, the sky is filled with stars, some of which are part of distant galaxies.
