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Every year, the same meteor showers recur once again.
This comet, imaged in 2015 and known as C/2014 Q2 Lovejoy, brightened sufficiently to become as bright as magnitude +4: visible to the naked human eye even under fairly light-polluted conditions. When Comet Halley returns, it will only be about 5-6 times brighter than this, but when Comet Swift-Tuttle next returns, it will be about 20 times brighter. Swift-Tuttle is far more massive and dangerous than the other known periodic comets. Although comets have been recorded for thousands of years, their periodic nature was only uncovered in the 18th century, by Edmond Halley.
As Earth revolves around the Sun, it periodically crosses cometary and asteroidal orbits.
Each year, Earth passes through the debris stream of various comets, including Comet Swift-Tuttle, which creates the visual phenomenon known as the Perseid meteor shower, and that of Halley’s comet, which creates two meteor showers: the Eta Aquarids and the Orionids. Although Comet Swift-Tuttle remains the single most dangerous object known to humanity, it’s Comet Tempel-Tuttle that has the honor of being the first comet linked to meteor showers (by John Couch Adams in the 1860s), being the parent body of the Leonids.
When crossing occurs, their debris impacts Earth’s atmosphere.
As they orbit the Sun, comets and asteroids typically break up over time, with debris between the chunks along the path of the orbit getting stretched out to create debris streams. These streams cause meteor showers when the Earth passes through that debris stream: with younger showers having more concentrated debris streams around the parent body’s nucleus and older showers having a more uniform debris stream. This image taken by Spitzer along a comet’s path shows small fragments outgassing, but also shows the main debris stream that gives rise to the meteor showers that occur in our Solar System.
The longer the period of the comet or asteroid, the faster its meteors move when striking Earth.
This map shows the debris stream of Comet Encke, a short-period comet in orbit around the Sun and the parent of the Taurid meteor shower. For many young comets or asteroids, there is a higher density of debris associated with the location of the main (parent) body of the debris stream, while older streams are more uniform. The Taurids and Geminids are marked by short-period parent bodies, with slower meteors, while the Leonids, Perseids, and Orionids have longer-period parent bodies, and hence, faster meteors.
Credit: M.S. Kelley et al., ApJ, 2006
Faster impact speeds lead to brighter shooting stars, creating spectacular meteor streaks.
A view of many meteors striking Earth over a long period of time, shown all at once, from the ground (left) and space (right). If a comet’s path crosses Earth’s orbit twice, its debris stream can create up to two meteor showers per year, as Halley’s comet does with the Eta Aquarids (peaking in May) and the Orionids (peaking in October).
Halley’s comet is designated as 1P by professionals: the first periodic comet ever discovered.
This 1986 photograph of Halley’s comet, taken from Easter Island on March 8 of that year, is likely the best view we’ll have until the comet returns to the inner Solar System in 2061. As of December 9, 2023, the comet now heads back into the inner Solar System, having just recently passed aphelion in its orbit.
It spawns two meteor showers: May’s Eta Aquarids and October’s Orionids.
This diagram shows Halley’s comet’s orbit, neglecting the gravitationally perturbative effects of the planets. Halley’s comet spends most of its time near aphelion, near the orbit of Neptune and beyond, but plunges into the inner Solar System once every 74-79 years, achieving speeds of 66 km/s (41 mi/s) when it crosses Earth’s orbit at both of two points.
Once Orion rises, meteors emerge about 10° north/northwest of bright Betelgeuse.
This simulated view of the sky at 1 AM on October 21, 2025 (from the mid-latitudes in the Northern hemisphere) shows the constellation of Orion rising in the East and its bright orange star Betelgeuse, the location of planet Jupiter, and an animation showcasing the direction and trajectory of meteors emerging from the Orionids’ radiant. Note that meteors can appear anywhere, but Orionid meteors will all trace back to this radiant point.
The coincident new Moon contributes no light pollution, making 2025 ideal for Orionid viewing.
In 2014, a bright Moon competed with the Geminid meteor shower, washing out many of the meteors and making them appear fainter and fewer in number to the human eye. 2025’s Perseids, in August, suffered a similar fate. However, the Orionid meteors shower in October of 2025 will coincide with a new Moon, reducing this form of light pollution to zero.
Credit: David Kingham/flickr
The best sights will appear between 11:30 PM on October 20th and 2:30 AM on October 21st.
From both hemispheres, Orion will rise a little before midnight on October 20th. From the Southern Hemisphere, you’ll want to face northeast after that to look for Orionid meteors; from the Northern Hemisphere, you’ll want to face southeast. Although meteors can appear anywhere, facing in these directions will allow you to capture the greatest numbers of meteors from where they first originate: up to one every two or three minutes at the shower’s peak.
From either hemisphere, find a dark location and set up a blanket, lounge chair, or upright chair.
This view of a single Orionid meteor, photographed alongside the constellation Orion, shows an excellent strategy for viewing a meteor shower: using a barrier (like a house) to block the majority of the ambient light pollution from the environment. A comfortable viewing experience enables you to spend longer watching the show, which typically peaks just after midnight during the meteor shower’s peak.
No need for binoculars or a telescope; take in the wide-field views.
Meteors can appear anywhere in the sky at any time of the night, although they will all be traceable back to the meteor shower’s radiant if they originate from that particular meteor shower’s parent body. Here, dozens of Orionid meteors are shown, but were captured all throughout the night, and aren’t necessarily aligned with the deep-sky photo shown as the “background” here. As a result, the meteor streaks appear unrelated, even though they are, in fact, all meteors originating from the same shower.
Once your eyes dark adapt, 20-to-30 meteors-per-hour will appear across the skies.
This composite, constructed from 19 separate frames of an overnight timelapse that captured the Orionid meteor shower, is properly aligned so that the various Orionid meteors all point back towards the radiant: their point of origin. This was constructed from the 2020 Orionid meteor shower; 2025’s will have ideal viewing conditions, with no Moon at all to pollute the sky with its light.
Meteors appear omnidirectionally, but all trace their origin back to the Orionids’ radiant: near Betelgeuse.
November’s modest Leonids (November 17th) and December’s abundant Geminids (December 14th) will yield fainter meteors than October’s Orionids.
This timelapse photo, from Jeff Sullivan, shows a composite of 2020’s Geminid meteor shower. Although the Geminids and Leonids will both only have a waning crescent Moon to contend with here in 2025, their meteors are slower and less bright than Orionid meteors. The October show, for the Orionids, coincides precisely with a new Moon, keeping light pollution at a minimum and apparent meteor brightness at a maximum.
Credit: Jeff Sullivan/flickr
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.
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