{"id":62702,"date":"2024-08-23T08:04:00","date_gmt":"2024-08-23T08:04:00","guid":{"rendered":"http:\/\/377372b2-faee-46fa-a2e5-264726eea716"},"modified":"2024-08-23T08:40:07","modified_gmt":"2024-08-23T08:40:07","slug":"a-transit-of-mercury-passing-across-the-sun-is-a-rare-thing-indeed-the-next-wont-happen-until-2032","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/a-transit-of-mercury-passing-across-the-sun-is-a-rare-thing-indeed-the-next-wont-happen-until-2032\/","title":{"rendered":"A transit of Mercury passing across the Sun is a rare thing indeed. The next won’t happen until 2032"},"content":{"rendered":"

Facts about Mercury transits, including when they occur and photos of the most recent events. <\/p>

By Iain Todd\n <\/p>

Published: Friday, 23 August 2024 at 08:04 AM<\/p>

\n\n

Did you know that there are just two times of year that a transit of Mercury can happen?<\/p>

Mercury, the innermost world of the Solar System, can only cross the Earth-Sun line of sight within a few days of either 8 May or 10 November.<\/p>

The next transit of Mercury will occur on 13 November 2032.<\/p>

Mercury Transit by Daniel, Ely, Cambs, UK. Equipment: Coronado PST, Televue 2.5x Powermate, ASI120-MMS Camera<\/figcaption><\/figure>

When is the next transit of Mercury?<\/strong><\/h2>

Find out when the next Mercury transit is happening via our table below.<\/p>

Date<\/th>Universal time<\/th>Separation<\/th><\/tr><\/thead>
7 May 2003<\/td>07:52<\/td>708\u201d <\/td><\/tr>
8 Nov 2006<\/td>21:41<\/td>423\u201d<\/td><\/tr>
9 May 2016<\/td>14:57<\/td>319\u201d<\/td><\/tr>
11 Nov 2019<\/td>15:20<\/td>76\u201d<\/td><\/tr>
13 Nov 2032<\/td>08:54<\/td>572\u201d<\/td><\/tr>
7 Nov 2039<\/td>08:46<\/td>822\u201d<\/td><\/tr>
7 May 2049<\/td>14:24<\/td>512\u201d<\/td><\/tr>
9 Nov 2052<\/td>02:30<\/td>319\u201d<\/td><\/tr>
10 May 2062<\/td>21:37<\/td>521\u201d<\/td><\/tr>
11 Nov 2065<\/td>20:07<\/td>181\u201d<\/td><\/tr>
14 Nov 2078<\/td>13:42<\/td>674\u201d<\/td><\/tr>
7 Nov 2085<\/td>13:36<\/td>718\u201d<\/td><\/tr>
8 May 2095<\/td>21:08<\/td>310\u201d<\/td><\/tr>
10 Nov 2098<\/td>07:18<\/td>215\u201d<\/td><\/tr><\/tbody><\/table><\/figure>

Mercury transit quick facts<\/strong><\/h2>

Mercury is so far away from us and so much smaller than the Sun that during a transit of the Sun it appears tiny against the solar disc, unlike the Moon during a solar eclipse<\/a>.<\/p>

However, transits of Mercury are visible from the entire day-lit hemisphere of Earth when they happen, whereas solar eclipses are viewable only from within a narrow track.<\/p>

Mercury<\/a> also travels through space faster than Earth, and its incredible orbital speed is why Mercury was named after the messenger of the gods<\/a>.<\/p>

When we see it moving across the Sun we are glimpsing its forward motion, rather than the changing perspective resulting from the Earth\u2019s motion.<\/p>

\"Mercury
Mercury Transit Draws to a Close by Charles Thody, North Lincolnshire, UK. Equipment: Skywatcher Equinox 80, Canon 40D, 3x Barlow, Celestron Advanced AVX mount.<\/figcaption><\/figure>

What a Mercury transit looks like<\/strong><\/h2>

When watching a transit of Mercury you should see the planet, in Sir William Herschel<\/a>\u2019s words of 1786, as \u201ca very black, round spot\u201d.<\/p>

It may be noticeably darker than any sunspots<\/a>, though small, dark objects on a bright background are hard to compare.<\/p>

If you are watching during the start or the end of the transit, look carefully at the moment when the full disc of Mercury is touching the inside edge of the Sun\u2019s disc (only three minutes after the beginning, or three minutes before the end of the transit).<\/p>

You may experience the momentary impression of a teardrop joining Mercury to the sky beyond the Sun.<\/p>

This \u2018black drop effect\u2019 is caused by optical defects and is more prominent when our atmosphere is turbulent.<\/p>

\"Mercury
Mercury Transit by Rob Little, Corbridge, UK. Equipment: Skywatcher 250, Canon DSLR EOS 30D<\/figcaption><\/figure>

When do transits of Mercury happen?<\/strong><\/h2>

There are 13 or 14 transits of Mercury over the course of a century. Transits of Mercury always occur in May and November.<\/p>

What makes them so oddly regular? It\u2019s to do with the eccentricity of Mercury\u2019s orbit and the resonance it has with Earth\u2019s orbit around the Sun<\/a>.<\/p>

Mercury has a more eccentric orbit than any other planet, being 0.31 AU from the Sun at the closest point in its orbit (perihelion) but 0.47 AU away at its furthest point (aphelion).<\/p>

\"Image
Image of Mercury taken by the MESSENGER spacecraft. Credit: NASA\/JPL-Caltech – NASA\/JHUAPL<\/figcaption><\/figure>

It rotates exactly three times for every two orbits round the Sun.<\/p>

This is described as a 3:2 spin-orbit coupling, and almost certainly results from the strong tidal forces experienced as a result of Mercury\u2019s changing distance but general proximity to the Sun.<\/p>

It rotates slowly, bringing opposite hemispheres to the sub-solar point at alternate perihelia.<\/p>

This results in its day length (measured from sunrise to sunrise) being twice as long as its year, which lasts 88 Earth-days.<\/p>

Mercury\u2019s apparent size changes by up to 20% and that\u2019s a function of it having the most eccentric orbit<\/a> of all the planets of the Solar System<\/a>.<\/p>

\"Composite
Composite image of Mercury transiting across the sun on 9 May, 2016, as seen by HMI on NASA’s Solar Dynamics Obersvatory. Credit: NASA\/SDO<\/figcaption><\/figure>

When we see a transit of Mercury in May, it\u2019s while Mercury is closer to Earth and so it has a 12 arcsecond disc.<\/p>

In November, the transits occur when Mercury is closer to the Sun so the planet appears slightly smaller from our perspective, about 10 arcseconds.<\/p>

At 88 days, Mercury\u2019s orbit of the Sun is almost a quarter of that of Earth, which means it\u2019s close to being in orbital resonance with Earth, hence the transits occur at the same times of year\u2026 for the time being.<\/p>

The timing between them will drift and though they occur in May and November now, that will change in centuries to come. But they\u2019ll always be six months apart.<\/p>

\"Mercury
Mercury passing in front of the Sun captured in 2006 by the Solar Optical Telescope. Credit: Hinode JAXA\/NASA\/PPARC<\/figcaption><\/figure>

How to observe a Mercury transit<\/strong><\/h2>

It is dangerous to look directly at the Sun, and for a transit of Mercury, there is absolutely no point in doing so!<\/p>

Mercury\u2019s apparent diameter as it crosses the Sun\u2019s disc is too small to see without magnification, and so eclipse glasses<\/a> designed for looking through with the naked eye will be no use, nor will pinhole-based gadgets.<\/p>

Mercury will look smaller than a large sunspot, but will not be too hard to see with a little help.<\/p>

If you have access to a solar telescope<\/a> (your local astronomical society<\/a> may have one) you will be well catered for.<\/p>

\"Astronomers
Astronomers and visitors observe Mercury transit the Sun, Sofia, Bulgaria, 11 November 2019. Here, transit-watchers are projecting an image of the transit onto a piece of white card. Photo by Petar Petrov\/Impact Press Group\/NurPhoto via Getty Images<\/figcaption><\/figure>

Otherwise, watch the safety advice video on the Open University website revealing how to watch a transit of Mercury<\/a> and get hold of a mirror and lens-based \u2018solar scope\u2019 that projects an image onto the inside of a box.<\/p>

If you have binoculars or a small telescope but don\u2019t have specialist solar filters<\/a> to cover the objective lenses, you can still use them to project an image of the Sun<\/a> onto a white card held about 0.5m beyond the eyepiece.<\/p>

You can tell when your telescope is aimed directly at the Sun without looking through the eyepiece by manoeuvring it until the shadow of its tube is circular.<\/p>

Who was first to observe a Mercury transit?<\/strong><\/h2>
\"Pierre
Pierre Gassendi (1592 – 1655), French philosopher and mathematician. Credit: Photo 12\/Universal Images Group via Getty Images<\/figcaption><\/figure>

Solar transits of Mercury are more common than a transit of Venus<\/a>.<\/p>

The first observation of a transit of Mercury was achieved on 7 November 1631 by the French Jesuit astronomer Pierre Gassendi (above), thanks to a successful prediction by Johannes Kepler<\/a>.<\/p>

There is no record of a transit of Venus having been observed until 1639, even though those can be seen by the naked eye (at the risk of damaging your eyesight).<\/p>

Edmond Halley observed a transit of Mercury while at St Helena on 3 May 1676, and realised that if observers at known but distant locations were to record the same transit, the parallax would give the information required to deduce the scale of the Solar System.<\/p>

\"Mercury
Mercury Transit and AR2543 by Pete Williamson, Shropshire, UK. Equipment: 90mm Coronado, 2.7x Barlow, ZWOASI174MM.<\/figcaption><\/figure>

That\u2019s why James Cook was sent to observe the 3 June 1769 transit of Venus from Tahiti.<\/p>

Less well known is that the expedition\u2019s astronomer Charles Green, along with Cook himself, observed a transit of Mercury on 9 November of the same year, from the shores of Mercury Bay in New Zealand.<\/p>

Green later fell ill, and died soon after putting out from Batavia (modern-day Jakarta) in 1771, but is credited with being the first to note that Mercury\u2019s crisp outline during transit demonstrates that the planet must have little or no atmosphere.<\/p>

Sir William Herschel caught only brief glimpses of the 4 May 1786 transit through cloud, but had better luck on 9 November 1802.<\/p>

Pictures of the transit of Mercury<\/strong><\/h2>

Below is a selection of images of recent Mercury transits. For more info on planetary astrophotography<\/a>, read our guide on how to photograph the planets<\/a>.<\/p>

And don’t forget to send us your images<\/a> or share them with us via Facebook<\/a>, Twitter<\/a> and Instagram<\/a>.<\/p>

\"Mercury
Mercury transit. ESA\/NASA Solar Orbiter, 3 January 2023<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury transitSOLAR DYNAMICS OBSERVATORY, 11 NOVEMBER 2019Credit: NASA\/SDO and the AIA, EVE, and HMI science teams<\/figcaption><\/figure><\/div><\/div>
\"Michael
Michael Bate, Milton Keynes. Equipment: Olympus E-PL7 camera, Sky-Watcher 200PDS, HEQ 5 mount, Baader AstroSolar filter.<\/figcaption><\/figure><\/div><\/div>
\"Sarah
Sarah and Simon Fisher, Worcestershire. Equipment: Canon EOS 600D DSLR camera, 127mm Maksutove-Cassegrain, homemade Baader Solar film filter.<\/figcaption><\/figure><\/div><\/div>
\"James
James Coard, County Down. Equipment: Canon EOS M100 camera, Altair Lightwave 66mm apo refractor, Hotech SCA field flattener, Baader solar filter.<\/figcaption><\/figure><\/div><\/div>
\"Andy
Andy Durham, Lincoln. Equipment: iPhone, Celestron SC6 Schmidt-Cassegrain, solar filter.<\/figcaption><\/figure><\/div><\/div>
\"Neil
Neil Allen, Norwich. Equipment: iPhone 8, Sky-Watcher Equinox 80 refractor, TS Optics Herschel wedge.<\/figcaption><\/figure><\/div><\/div>
\"Peter
Peter Lewis, Sutton, Greater London. Equipment: Samsung smartphone, Dobsonian telescope, Snapseed mobile app.<\/figcaption><\/figure><\/div><\/div>
\"Andrew
Andrew Hill, Exeter Airport. Equipment: Google Nexus 3A smartphone, Sky-Watcher Explorer 130PS Newtonian, Explore Scientific solar filter.<\/figcaption><\/figure><\/div><\/div>
\"A
A focal length of 1,000mm (or above) is needed to define Mercury against the Sun\u2019s disc. Credit: Pete Lawrence<\/figcaption><\/figure><\/div><\/div>
\"A
A Mercury transit captured by NASA’s Solar Dynamics Observatory on 9 May 2016 . Credit: NASA\/SDO and the AIA, EVE, and HMI science teams.<\/figcaption><\/figure><\/div><\/div>
\"Composite
Composite image of Mercury transiting across the sun on 9 May, 2016, as seen by HMI on NASA’s Solar Dynamics Obersvatory. Credit: NASA\/SDO<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury passing in front of the Sun captured in 2006 by the Solar Optical Telescope. Credit: Hinode JAXA\/NASA\/PPARC<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury ISS Solar Transit by Eric Toops, Florida, USA.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit by Simon Franklin, Leeds, UK. Equipment: Sony alpha-5000, Skywatcher200p (EQ-5), home-made Baader Solar Filter.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit by Paul Gavey, UK. Equipment: Canon 5DMKII, Canon lens 200-400, inbuilt 1.4 teleconverter, Baader film filter.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit by Karl Lee, Southport, UK. Equipment: Meade ETX90, Iphone 6s, Solar Filter, Blue Filter<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit near Sunspot #2543 by John Chumack, Lake Erie, USA. Equipment: Lunt 60mm\/50F HA scope, QHY5IIL CCD camera, 2x barlow.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit Over Ha Disk by Stuart Green, Preston, Lancashire, UK. Equipment: 150mm solar telescope, double stacked hydrogen alpha etalons, Basler acA1920-155um, Sony IMX174 sensor.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit Close Up by Chris Higgins, Ripon, N Yorks, UK. Equipment: LUNT 60 Ha solar scope, ZWO ASI 174 MM camera, Televue 2.5x Powermate.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury in Transit by Phil Benson, SE Essex, UK. Equipment: Lunt LS152 Ha Solar Scope, PG Flea3 camera.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit and AR2543 by Pete Williamson, Shropshire, UK. Equipment: 90mm Coronado, 2.7x Barlow, ZWOASI174MM.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit by Nico Altena, Netherland. Equipment: WO 98MM, CA-K B1800 Module, 2X Barlow lens, ZWO ASI 174MM.<\/figcaption><\/figure><\/div><\/div>
\"Mercury
Mercury Transit by Daniel, Ely, Cambs, UK. Equipment: Coronado PST, Televue 2.5x Powermate, ASI120-MMS Camera<\/figcaption><\/figure><\/div><\/div>
\"2nd
2nd Contact by Paul Read, Northamptonshire, UK. Equipment: Canon 600D, 17mm Baader Hyperion, Baader Solar Continuum filter, Lunt Hershel Wedge, Skywatcher ED80 DS Pro, Skywatcher HEQ5 Pro.<\/figcaption><\/figure><\/div><\/div><\/div>