Halley's Comet and its return in 2061
The next perihelion is expected on 28 July 2061. It last swung past in February 1986, and its orbit takes about 75 to 76 years, so most people get one chance.
Updated on October 7, 2026
The orbit
- Official designation
- 1P/Halley
- Last perihelion
- 9 February 1986
- Last aphelion, its farthest point
- 9 December 2023
- Next perihelion
- 28 July 2061
- Orbital period
- about 75 to 76 years
- Perihelion distance
- 0.586 AU, inside Venus’s orbit
- Aphelion distance
- 35.1 AU, beyond Neptune
- Nucleus
- about 15 × 8 × 8 km
- Orbital direction
- retrograde, against the planets
Why the period is not a fixed number
Recorded returns have come between 74 and 79 years apart. Jupiter and Saturn tug on the orbit at every pass, and the comet itself pushes back: as the nucleus warms near the Sun, jets of gas and dust act as a weak, uneven rocket. Those non-gravitational forces are why predictions a few returns ahead carry real uncertainty, and why the 2061 date can still shift by days.
The 1986 return was poor for observers — the comet was on the far side of the Sun from Earth at its brightest — but it was the one we visited. Five spacecraft flew past, and ESA’s Giotto got within 596 km and sent back the first images of a cometary nucleus: a dark, peanut-shaped body reflecting about 4% of the light hitting it, among the blackest objects in the Solar System.
You can see its dust every year
Earth crosses the debris stream left by Halley twice a year, which gives two meteor showers: the Eta Aquariids in early May and the Orionids around 21 October. Those grains were shed on earlier passes, so while you wait for 2061 you can watch bits of the comet burn up on schedule.
Source: NASA — Planetary Fact Sheet (NSSDCA) e NASA Science: Solar System
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How long is left until 2061
From today, roughly 35 years remain until Halley’s next perihelion. Anyone younger than 35 wasn’t born for the 1986 pass, which is why "Halley's Comet and its return in 2061" calls this a once-a-generation event.
Words on this page
Astronomical unit
The solar system’s reference distance, fixed at exactly 149,597,870,700 metres since 2012, close to the average Earth–Sun distance. It saves writing every planet’s orbit in kilometres with ten digits.
Standard definition by IAU — International Astronomical Union · Astronomical unit
Launch window
The span of time in which a rocket can lift off and still reach its planned orbit or destination. For a trip to another planet that window can last only a few weeks and only returns at the next favourable alignment, so missing it costs months or years of waiting.
Exoplanet
A planet orbiting a star other than the Sun. Most were found indirectly, by the star’s faint dimming as the planet crosses in front of it (transit) or by the gravitational wobble it causes in the star (radial velocity), not by direct image.
Standard definition by NASA Exoplanet Archive · Exoplanet
Standard uncertainty
The margin attached to a measured value, usually written in parentheses on the last digits. A constant that is "exact by definition" has zero standard uncertainty; a measured one, like the gravitational constant G, always carries some.
Standard definition by BIPM — Bureau International des Poids et Mesures (SI) · Standard uncertainty
Atomic number
The number of protons in an atom’s nucleus, written Z. It is this number, not the mass, that defines which element an atom is: every atom with 8 protons is oxygen, whether it has 8 or 18 neutrons.
Standard definition by IUPAC · Atomic number