Comets are bright silver streaks of light in the night sky. We know that comets have freezing cold temperatures. Why is it that certain comets like Halley’s Comet are famous? How long do comets live? What to they revolve around? Do they exist beyond our solar system? How to spot a comet in the sky? Here are some amazing comet facts and information to add to your knowledge.
What is the Lifespan of Comets?
Comets can have a limited life span and, sooner or later, break down due to the incredible speed with which they move and also the size, which decreases over time. This is because every time they pass close to the Sun, they lose mass due to a process called sublimation. Thus they disappear after thousands of years completing the cycle around the larger star of the Solar System.
What Are Comets Made Up of?
- The core of these bodies has a frozen mixture of water, methane, ammonia, and carbon dioxide, as well as rocks, dust, and other space debris. So it is much more than the simple water that makes up our common ice.
- It is not yet known what lies beneath the ice of a comet’s core.
- Each comet has a nucleus that can range from a few meters to several kilometers wide all nuclei are made of ice.
- The atmosphere of the comet, also called “coma”, is formed by dust and gas that surround the nucleus.
- A comet diagramatically labelled as nucleus, coma, dust tail and, ion tail. The nucleus as mentioned consists of water, rocks, dust, and carbon compounds. Coma is a cloud of gases surrounding the nucleus. Dust tail is composed of dust particles that are left behind and ion tail is produced due comet’s interaction with solar winds.
Where Do Comets Come From?
It is suggested by scientists that there are regions in the solar system that produce the comets. There are two such regions known as, Kuiper Belt and Oort Cloud.
Kuiper Belt is similar to the Asteroid Belt and can be found in the inner solar system. Comets in the Kuiper Belt have short orbital periods comparative to the planets.
Oort Cloud is located further in the solar system. Its comets have relatively longer orbital periods.
Facts About Comet Tail and Light
- Although they look quite bright, comets reflect only 4% of the light they receive. The rest is absorbed.
- The comet’s tail is part of the coma that blows away from the nucleus.
- The dust on the tail reflects sunlight and that’s what makes the comets look so bright.
- What we see is a yellowish tail that accompanies the comet, but it may have a second extension, in the blue color, formed by the ionized gases.
- The second tail of the comet can extend for more than 570 million kilometers.
- The ionic tail is the result of the collision of the solar winds against the comet.
How many comets are there in the Solar System?
At this time, there are at least 3,000 known comets in our Solar System.
Comets in History
- Formerly, comets were used to cause fear in people. In this way, profiteers of the market sold umbrellas, gas masks and “anticometa” pills.
- The first comet known to humans was the Great Comet of 1680, discovered by Gottfried Kirch.
- Halley’s Comet was the first comet to be identified as a periodic comet. The estimate is that Halley will reappear only in July 2061.
- In 1995, Alan Hale of New Mexico and Thomas Bopp of Arizona discovered one of these celestial bodies after it passed near the orbit of Jupiter. This comet became known as Hale-Bopp.
- In 1705, Edmond Halley predicted, using the laws of Newton’s motion, that the comet seen in 1531, 1607 and 1682 would return in 1758. The comet returned as planned, and was later named in his honor. The average period of the Halley orbit is 76 years, but you can accurately calculate dates reappearances.
- Why is the Halley’s Comet so famous?
- Discovered in 1993, Comet Shoemaker-Levy 9 is not as famous as the Halley, but became known to the public after breaking into pieces and dispersing on Jupiter.
- Comet Shoemaker Levy 9 was the first comet to be observed colliding with another object in the Solar System. In this case it collided with the planet Jupiter, one of the most studied astronomical events in history.
How Do Comets Die?
In addition to loss of mass and volatile substances, the comet can “die” by colliding with a larger body or even exploding depending on the gravity of the Sun.
A comet may cast some pieces of rock, and these fragments may fall to the earth like a meteor shower.
How to Spot a Comet in the Sky
Comets present a spectacular sight in the night sky. It is usually very hard to see comets. They can be seen once every hundred years. If you want to see a comet, the best approach is to keep your eyes open for news of any comets approaching near the earth. If you hear any such news, then here is how to spot the comet in the sky.
- Check whether the comet will be visible from your country/ place.
- Telescope is not necessarily required. But you can get one if you want to have a good view.
- Make sure you are away from noise of light. Be at a place where there is no disturbance of light from the city.
- If the comet is big enough, you will be able to catch a good view, else binoculars or telescope can be handy. It depends whether the tail will be visible or not on the fact whether the comet touches the earth’s atmosphere. Contact with the atmosphere will make its tail brighter due to friction.
Most Famous Comets
- Comet Halley – Most famous of all comets and can be seen every 76 years.
- Comet Encke – The second comet to be identified as a periodic comet.
- Comet Hyakutake – Closes cometary approaches to earth. Was last seen in 1996.
- Comet Shoemaker–Levy 9 – Famous because of its collision with Jupiter in July 1992.
Interesting Facts About Comets
- Comets are also called as dirty snowballs because they are hugely composed of dust and are extremely cold.
- Comets orbit the sun in an elliptical orbit just like the planets. In fact, their orbits are lot more elongated than that of the planets.
- The tail of a comet consists of dust. It shines because of reflection of light from the dust. Comets entering the earth’s.