Halley’s Comet has begun its long journey back to Earth


After almost 38 years, he finally decided to go for it way return to earth. In recent days in fact Halley’s cometthe most famous in history, achievedaphelion, the farthest point from the Sun, about 5 billion km away. It was last in the same place in its orbit in April of the year 1948while its last point of closest approach to the Sun now dates to 1986. So, according to predictions, on its usual 76-year journey around our star, it will return in 2061. Here’s what we know Comet and his travels.

Halley’s comet

Halley’s Comet, officially 1P/Halley, was first noticed by the German astronomer Edmond Halley, who was the first to observe it periodicitysuccessfully predicting the return of the comet that now bears his name in 1758. Abbreviation 1P shows that Halley’s was the first periodic comet discovered. Remember that periodic comets have orbits of less than 200 years. To date, we know of 472, but as observations of the sky move further and further up the magnitude scale, we discover fainter and fainter periodic comets. In addition, two annual meteor showers are associated with Halley’s Comet: the Eta Aquarids May and Orionids October

The orbit of Halley’s Comet

Halley’s comet travels by sun on a flattened elliptical path that brings it closer to the Sun and then takes it far beyond the outer limits of our Solar System. In particular, we know that since February 9 1986, when it reached perihelion (closest point to the Sun), it began its long journey back into space. And from that moment until today, the comet has moved inexorably away from the Sun, beyond the orbit of Neptune. But in the last few days, she finally got around to itaphelionthe point at which the comet began to approach the Sun again for the first time in nearly 38 years.

Travel speed

We know that Comet it moves faster when it is at perihelion and slower at aphelion (Kepler’s law). Just imagine it, like NASA, reached an orbital speed of 0.91 km per second (3,272 km per hour) at aphelion, while when it was last at perihelion in 1986, it reached a speed of 54.55 km per second (195,609 km at the time). So it goes without saying that this time too its speed will increase again, at first more slowly, until it reaches perihelion again on July 28, 2061.

Looking to 2061

But what can we expect from Halley’s Comet’s next visit? The most favorable time of the year (2061) to admire its passage towards the Sun, as reported Space.comwill be in summerwhen the comet will be on our same side sun and it will look at least 10 times brighter. It will be an evening show: initially its visibility will be limited by the presence Moon full on August 1, but by the evening of August 4, the comet will shine in all its glory in a completely dark sky. While we can make fairly accurate predictions about what Halley’s Comet will do on its next visit, no one can yet predict what time in our night sky during that time. So all we have to do is wait.


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