Halley's Comet

Halley's Comet | Komèt Halley

Introduction to RCH2000

Hello RCH2000 listeners, hello everyone.

Welcome to the column "Astronomy at Home with Captain Astro".

My name is "Captain Astro". Or Dr. Rulx Narcisse, but I prefer to be called Captain Astro.

I am a professional astronomer at the Société Haïtienne d'Astronomie.

Come closer to hear and understand.

Introduction

I will tell you today about the most famous comet in history, Halley's comet. He is more famous, not because he made a catastrophe, but because it was the one that astronomers came to understand first in the category of space objects called comets. As the astronomer who managed to do this work first was called Edmond Halley, it also bears that name. But for me, it is also an important comet, because thanks to the observation of this comet in 1986, with my father, when I was a 13-year-old teenager, I became interested in astronomy to become today a professional astronomer.

What is committed?

Comets are also a category of objects in our solar system, in addition to the planets, but they are smaller, they are made of water ice mixed with rocks, and above all, they do not rotate strongly in the same plane as the planets, they can take any plane relative to the ecliptic, depending on where they originate. And they are very far away, either in the Kuiper belt area in the area beyond Neptune, or further still at the end of the solar system, in a region that surrounds the entire solar system astronomers call the Cloud of Oort; and if they come from the Oort cloud, they can reach the inside of the solar system in any plane, on any angle. This is why astronomers classify comets into 2 categories; a first category called comets with a short period, which will not take more than 200 years to circle the Sun and return to the Earth, and a second category called comets with a long period which, of course, takes more than 200 years. The latter category of comets originates from the Oort cloud.

Halley's Comet I will talk about takes 76 years to return to Earth. This means its is in the first category of the short period, and they even put it as one of the category or family of a group of comets that also make their orbits in about 76 years.

Halley's Comet

If you read me correctly, you will understand that the last passage was in 1986, when Duvalier left power, and we can calculate that it will happen again in 2061.

But history of this comet is very nice...well, you can't be surprised about that...As I told it recently, it's the first object that they will be able to understand in his category. Because in the past, they couldn't understand the natural phenomenon of water ice melting in space to make a long tail of gas appear behind it, they used to be afraid and think that since comets appear in the sky, there is something bad that will happen

We'll get to that record soon. Don't hurry.

Let's take a look back at the orbits of comets. In addition to the direction and angulation that can be different from the ecliptic plane which is the plane of the planets, the shape of the orbits are not the same. Comets have very eccentric orbits, in other words their orbits are not round at all, but rather stretch out from where they come from to arrive near the Sun.. This is also why they take their time to come back, such as Halley's comet which takes 76 years. Well, this is how comets can happen until 0.59 Astronomical Unit, 88,262,743.7 km from the Sun, called perihelion; and when we are at the other end of its orbit, which is called aphelion, as far as possible from the Sun, it is at a distance of 35.5 Astronomical Unit, or 5 310 724 409.53 km.

[Well, all these parameters allow astronomers to calculate its orbital speed when it is closest to the Sun, where it can move at 54.5 km/s while when it is far from the Sun, don't forget it is called aphelion, it can move on its orbit at 910 m/s. You will notice that Halley's comet, like all objects in our solar system, moves faster when it is closer to the Sun, in perihelion. The last time it was in perihelion was on February 9, 1986, and the next time will be on July 28, 2061. The first time they calculated and confirmed the perihelion date was in 1758 thanks to Edmond Halley, we remember, the astronomer who also gave him his name, even when he had already died a few years before, in 1742.]

Long history

History has reported that astronomers have always seen comets, namely an object in the sky with a tail trailing behind it like a bunch of hair. That's why they called it comet, a word derived from cometa, a Latin word that means a lot of hair. There were astronomers in the past who documented their observations of this phenomenon, in many civilizations. For example, in some Chinese annals in 611 BC, in the observations of some Babylonian and Chinese astrologers in 164 BC, in Roman documents about Nero in 66. Well, there are traces of this comet in many Chinese archive documents in the past. It's hard to tell you everything... you understand... but I can't help but mention that it was mentioned at the time when Attila defeated the Huns in 451.

Well, in the English Archive, there is a story that marked people who believed a lot in the misfortune that can happen when a comet appears in the sky, and for their misfortune, when the comet appeared in the year 1066, they were attacked de Guillaume le Conqurant, a French king from Normandy who will reign for several decades in England. Big history... Halley's Comet appeared in the sky even while a famous battle was taking place, the Battle of Hastings... There are objects that still exist that have Halley's Comet on it and remind them of this defeat, such as tapestry The Bayeux.

All reports and historical archive documents will be used by Edmond Halley to analyze the periodicity of some comets, depending on how he wanted to understand this phenomenon. That is how it will be realized that the comet phenomenon of 1531, 1607 and 1682 should involve the same comet. That's how he came up with the theory that comets would travel on an elliptical, eccentric orbit that takes 76 years. So that's how he gave the date 1758, as I said recently. In 1705, he published an article entitled "Synopsis Astronomia Cometicae" in the "Philosophical Transactions of the Royal Society". History will show that he calculated things correctly, when the comet appeared in 1758, as he calculated it.

The history of astronomy also reports that there were some other astronomers who worked on this record, because it is a phenomenon that is also based on the science of gravity that a geat man called Isaac Newton brought at that time. There were some scientists who made some estimates of the return date of Halley's comet that are not too different, by adding some other orbital parameters such as the influence of the planets Jupiter and Saturn. But the comet appeared exactly in 1758. The return of Halley's comet on the date he gave was a great victory for these two great men in astronomy: Newton and Halley.

Modern observations

Let me tell you that over time, technology will advance, astronomers will observe Halley's comet, and other comets as well, with even more precision, and will find more details to understand and confirm their composition, position and other details as well.

There will begin to be large astronomical observatories to watch the sky, day and night, there will be space probes to bring them closer to the comets. Well, so, in the passage of that comet, Halley's comet, in this year 1986 that I started talking about, there are several devices that were oriented to the comet.

Many scientific mobilizations were carried out, such as the Giotto probe sent by the ESA, the Vega 1 & 2 probe sent by the USSR. Altogether, there were 7 space probes that went to visit it, from near or far to study it. Here are some details about them:

Giotto, which I started to say, was sent by ESA since 1985 and reached a distance of 596 km from Halley's comet on March 15, 1986. It sent us to Earth a lot pictures and lots of data on the composition and structure of the comet. Well, this Giotto even managed to make a second pass by the comet in July 1991.

NASA, itself, sent 2 space probes; also when 2 left in 1978, but they arrived only a few million km from the comet; These probes were named ICE and ISEE-3. ICE studied the environment of Halley's comet at a distance of 28 million km on March 24, 1986. It measured the magnetic field and charged particles surrounding the comet.

ISEE-3, for its part, studied the interaction of the solar wind with Halley's comet while it was at a distance of 10 million km on the day of March 11, 1986.

Japan was on this affair of sending 2 space probes: Suisei and Sakigake.

The probe named Sakigake was positioned at 6.9 million km on March 11, 1986 to study the interaction of the Sun's wind with the comet as well.

The probe named Suisei was positioned at 150,000 km on March 18, 1986, so it came closer to the comet, and this allowed it to study the composition of the gas surrounding the comet and in its tail.

Well, we know, Russia must be there as well, we mentioned the Vega 1 and Vega 2 missions recently. Well, at that time, it was through the USSR that these 2 probes were born and launched into space in 1984. They passed Halley's Comet on March 6 and 9, 1986 at a distance of 8,890 km to Vega 1 and 4000 km for Vega 2. These probes were even able to successfully land devices on the comet to analyze its surface. Big event...

The Netherlands also sent a probe to the comet: Astron, that's what they called their probe. They launched it in 1983 and it reached a few million km from the comet in March 1986 to observe the UV rays that this body was giving off.

We see, many robotic mobilizations have been done to observe Halley's Comet. And for people, say astronauts. What was it like to commit this?

There was a space shuttle, called Challenger, which was expected to take a closer look, with 5 astronauts on board, but damaged, it exploded on January 28, 1986, all astronauts died.

Other robotic space probes have sent valuable information, photos, and videos to us on Earth. This allowed the scientific community to better understand comets. This will not prevent them from sending other missions to other comets however; for example the Stardust mission that landed on comet Wild 2, in 2004, to take a small sample to bring back to Earth. We will not forget to commit 67P/Churyumov-Gerasimenko in the years 2014-2016, where the Rosetta probe was placed, always to do scientific analysis for us.

Comets and the origin of water on Earth

Come on, it's a very interesting object. Although we focus more on Halley's comet, we will understand in general all comet records are important, especially when we begin to understand that in the past there were many comets that collided with the Earth, and it would be these collisions that would participate for much of making there is liquid water on Earth. Do not forget, comets are made of water ice, and it would look like where the Earth is positioned, even though there may be liquid water, but the Sun went through a period when it gave too much wind that would have blown all the ice and water far away in the Solar System. So thanks to the comets, water returned to Earth.

Conclusion

Well, there, we will be forced to stop, even though there are many other things to say about Halley's comet or all the comets. Don't forget, the rubric "Astronomy at home with Captain Astro" is here to help you understand astronomy in Haitian, a language also known as Creole. Call me or text me with questions on 38407775; or search «Société Haitienne d'Astronomie» on Google or with «Artificial Intelligence» to find us. We are waiting for comments and questions.

Thank you, and see you soon