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Halley’s comet only visits every ~76 years, but its meteors arrive twice each year.
The most famous comet of all — Halley’s comet — returns to our inner Solar System every ~76 years.
Halley’s comet made its most recent approach into the inner Solar System in 1986. In this long-exposure telescopic photograph, both the comet’s white dust tail and its blue ion tail are visible. However, the particles that make up a meteor shower are not visible here, but rather originate from the broken-up fragments of the comet’s nucleus. (F. Carter Smith/Sygma via Getty Images)
Using Newton’s gravitational law, Edmond Halley calculated that this 1682 comet also appeared in 1607 and 1531.
The orbit of Halley’s comet is largely determined by the Sun and makes a nearly perfect ellipse, but the periodicity of Halley’s comet has varied from 74 to 79 years as various close encounters with the outer planets have perturbed its orbit over the centuries. Its 76 year period is only a long-term average. (NAGUALDESIGN / WIKIMEDIA COMMONS)
In 1705, he predicted the comet’s 1758 return and every subsequent ~76 years thereafter, periodically.
This view of Halley’s Comet was photographed from space by the Soviet Probe “Vega” in 1986. The color gradient showcases the progressively decreasing density as particles are expelled from the comet’s nucleus. (USSR/Liaison via Getty Images)
This prediction was confirmed by Johann Georg Pallich, who observed Halley’s comet on Christmas Day, 1758.
Every ~76 years, Halley’s comet returns to the skies of Earth. Halley successfully identified the comet’s 1682 appearance with two prior periodic appearances, enabling a prediction of its return in 1758. Although Halley died in 1742, his predictions were not only borne out in that year, but periodically thereafter, including in a spectacular display in 1910. (Rodolfo Paoletti, L’Illustrazione Italiana, Year XXXVII, No 21, May 22, 1910; DE AGOSTINI VIA GETTY IMAGES)
Every 74–79 years, the comet returns: most recently in 1986 and next in 2061.
This view of Comet Halley’s nucleus was obtained by the Halley Multicolour Camera (HMC) on board the Giotto spacecraft, as it passed within 600 km of the comet nucleus on 13 March 1986. The comet was clearly quite active at the time. (ESA/MPAE LINDAU)
Like all comets, fragments break off when it approaches the Sun.
The debris stream of a comet — shown as the thin line in between the fragments — traces its orbit and give rise to meteor showers. Although the entire stream may be millions of kilometers wide, the peak is much narrower. When the Earth crosses the center line, that’s a sign that we’re at risk of being hit by the parent comet itself, if both it and us occupy the same space at the same time. (NASA / JPL-CALTECH / W. REACH (SSC/CALTECH))
Cometary debris spreads out along its orbit, creating meteors upon encountering our atmosphere.
The debris stream of a comet, like Comet Encke (shown here) or Comet Swift-Tuttle (which created the Perseids) or Comet Tempel-Tuttle (which causes the Leonids), is the cause of meteor showers on Earth and all other worlds in the Solar System. John Couch Adams’ 19th century identification of Comet Tempel-Tuttle with the Leonid meteor shower was the first link ever made between these two phenomena. (NASA / GSFC)
Earth passes through this debris stream annually in mid-to-late October, creating the Orionids meteor shower.
Meteors streak across the night sky during the Orionid meteor shower. Three of the streaks here can be traced back to the same point in the sky: the meteor shower’s radiant. This provides evidence that they arose from the same parent body. The other streak is either a satellite or an unrelated meteor. (Yuri SmityukTASS via Getty Images)
Unlike most periodic comets, Halley’s comet crosses Earth’s orbit twice, also giving rise to May’s Eta Aquariids.
This illustration of Halley’s comet’s orbit shows its periodic motion with respect to the outer planets (including Pluto, illustrated by the outermost curve), as well as its inclination to the plane of the Solar System. The orbit actually crosses Earth’s in two places: unusual for a periodic comet. (BSIP/UNIVERSAL IMAGES GROUP VIA GETTY IMAGES)
A meteor storm is characterized by showers of shooting stars that are so intense, they occur every few seconds on average. The meteor storm of 1833, associated with the Leonids, was a legendary outburst. It was John Couch Adams who first identified and predicted the link between periodic comets and meteor showers. (ADOLF VOLLMY, ENGRAVING FROM 1889)
To catch the Orionids, observe the southeast skies starting at midnight.
Although Orion is best known as a winter constellation, it rises in the October skies later in the night. The Orionid meteors originate from a point just slightly above Betelgeuse if you draw an imaginary line from the belt to this bright red star, and radiate throughout the sky. At its peak, you can expect to see around ~30 meteors per hour. (MARC LAYER / GEOF (L); TONYNETONE / FLICKR (R))
These meteors all originate from the constellation of Orion, appearing throughout the sky.
The constellation of Orion is visible in the upper right of this image, with a bright meteor originating from the radiant of the Orionids captured at left. Orionid meteors, although they all originate from the same portion of the sky, can form a brilliant streak at any location in the sky. Wide-field views are always best for viewing meteor showers. (MIKE LEWINSKI; IKEWINSKI / FLICKR)
The peak yields ~30 meteors-per-hour, occurring from midnight to dawn on October 21–22.
Here, a bright Orionid meteor can be seen radiating from the constellation of Orion, along with its inherently green color. Meteors come in a variety of colors and brightnesses, although most will appear faint and white to the human eye. Nonetheless, the proper photographic techniques can often capture details invisible to the unaided eye. (BROCKEN INAGLORY / C.C.A.-S.A.-3.0)
Only December’s Geminids surpass the Orionids for the remainder of 2020.
This brief timelapse from the 2013 Geminid meteor shower showcases a common point-of-origin for all Geminid meteors; the ‘exception’ that can be seen is a moving satellite. December’s Geminids, along with August’s Perseids, are typically the years best meteor showers, but others such as the Quadrantids, the Orionids, or the Leonids can also be spectacular in a given year. (ASIM PATEL / WIKIMEDIA COMMONS)
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
