Cranbrook to Miss Out on Historic Transit of Mercury

A once in a generation astronomical event is happening Monday. How can Cranbrook observe it?

By Dan Hicks

Mercury – messenger to the gods in Roman mythology, is our smallest planet, the closest to the sun; and is one of our four inner fellow rocky planets, contrasting with the four outer gas giants. Mercury is oven hot when exposed to the sun, yet so deeply frozen in its shadows that ice exists within its polar craters.

Moonlike in appearance and two fifths Earth’s mass, Mercury is a little larger than our moon and both have suffered the same fate as victims of our early solar system’s heavy debris bombardment; since they are essentially devoid of atmospheres and have been geologically dead for billions of years, their impact craters remain unchanged – evidencing their hard-luck histories.

Both Jupiter moon Ganymede and Saturn moon Titan are larger than Mercury. Our second densest planet, Mercury is almost as dense as Earth and, with a liquid iron core constituting 55% of its volume and a single continental plate – the little planet is shrinking!

At 3.2 light minutes from the sun, Mercury orbits the sun every 88 Earth days and rotates on its axis every 59 Earth days, meaning that it rotates thrice every two Mercury years – giving Mercury our solar system’s longest day – 176 Earth solar days (no need for Daylight Saving Time on Mercury).

At 6.0 light minutes from the sun, Venus, with its searing dense carbon dioxide atmosphere, is our hottest planet; third planet Earth orbits at 8.3 light minutes distance – 1 astronomical unit; and Red Planet Mars – our future second home, waits patiently at 12.6 light minutes out from the sun.

Though Giovanni Zupi’s 1639 telescopic observations of Mercury showed it as having phases like the moon and Venus – explainable only by its orbiting the sun, we owe our intimate knowledge of the planet to two US National Aeronautics & Space Administration (NASA) probes; Mariner 10, active in 1974-75 and Messenger, active from 2004 to 2015.

Messenger orbited Mercury 4,000 times, leaving a wondrous photographic legacy before running out of fuel and crashing onto the planet’s surface; its more primitive predecessor had a kinder fate – consigned to eternity as a solar satellite.

As Mercury never extends any further than 28 degrees from the sun in our sky, it is only visible as a morning or evening star and, in the November 28th dawn, makes its best apparition of the year, ascending to 15 degrees in our eastern sky 45 minutes before sunrise – shinning at a bright minus 0.6 magnitude; the morning star planet will be the most prominent stellar object on the eastern horizon. A telescopic view would show the planet displaying a moonlike orbital phase.

Apparitions aside, Mercury’s outstanding performance will be its November 11th inferior conjunction when it transits across the face of our sun – a significant astronomical event that will not be visible again from the Kootenays for another 33 years – November 9th, 2052.

But our upcoming November 11th transit is the most favorable of the century – the centers of the two heavenly spheres come to within 76 arc seconds of each other. Mercury’s orbit around the sun is inclined 7 degrees to our Earth’s orbit around the sun, hence Mercury’s path across the sky intersects the sun’s path – the ecliptic – at that angle (see diagram).

However, observation of Mercury’s transit is possible only through a specially-equipped telescope, a basic candidate being a refractor with a 13 cm (5 inch) objective lens and an 800 mm focal length and, most importantly – fitted with a front-aperture solar filter.

Attempting to observe the sun through any makeshift contraptions will damage a would-be observer’s eyesight and pointlessly so – Mercury is a mere pinpoint against the solar surface, its apparent diameter being only 1/194th of the apparent solar diameter.

Specifically for Cranbrook, Timeanddate.com lists the times of Mercury’s ingress onto the sun’s disc, midtransit, and egress from the sun, features a transit animation, and for restless transit enthusiasts – includes a countdown clock.

Accordingly, I delivered a formal letter to College of the Rockies President David Walls on November 4th asking that, utilizing college equipment and personnel, he arrange a public viewing of the November 11th Mercury transit for the citizens of Cranbrook, so that they might enjoy the same celestial viewing opportunities as those that have been arranged for Calgarians.

Regrettably, neither my letter nor a November 6th follow-up email elicited a response from the college.

Our local institute of higher learning has no history of engaging the public for special astronomical events and this established institutional indifference is likely well entrenched in its collective psyche. Ironically, the college’s heraldic motto – AD CULMINA – to the summits – suggests that when the November 11th sun arises over the Rockies to the east-southeast, with Mercury’s transit already in progress, it would be greeted by an enthusiastic little crowd of Cranbrookers atop a community forest promontory, awaiting their turn to directly view – through college telescopes – our smallest planet smoothly sliding across the blazing face of our great sun; momentarily contemplating the fragility of our own precious planet while gazing upon a neighboring world of roasting-frigid rock.

But sadly resigning to the status quo, I see the likelihood of such proactive collegial engagement linking the local citizenry to unique astronomical phenomena as being akin to rather unimaginable and macabre doomsday occurrences; eg the Rockies tumbling into the sea, reanimated dinosaurs reclaiming Cranbrook, and Justin apologizing to Jody (arranged from the unlikely to the unthinkable).

Though Cranbrook may fare better in 2052, when once again we will have an opportunity to view a transit of Mercury, we deserve more here and now from our college on the hill.

sources: Royal Astronomical Society of Canada Observer’s Handbook 2019, SkyNews Magazine November-December 2019, Wikipedia.org, & Worldatlas.com.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Chernove set to take on epic 1,000 kilometre cycling challenge

A local Paralympian is taking on an epic cycling challenge. Tristen Chernove… Continue reading

From baseball stars to forest fires: Southeast Fire Centre water bomber has an interesting past

Tanker 489 is stationed in Castlegar this year, but in the 1960s it belonged to the L.A. Dodgers.

Cranbrook RCMP looking for vehicle, driver involved in hit and run

RCMP are looking for the owner of a white Toyota Corolla that fled the scene

Cranbrook Cenotaph names get a touch-up

Legion members repaint 166 names, marking three wars, for the first time in monument’s history

BookNotes: The Australian prison colony’s first lending library

The books brought over by various officers proved quite popular with the convicts

B.C. identifies 20 new COVID-19 cases, travellers specified in count

Pandemic total 3,028 cases, 51 people from outside Canada

Survey, hotline launched amid probe into racist blood-alcohol guessing game at B.C. hospital

Mary Ellen Turpel-Lafond has been appointed to lead an investigation by Health Minister Adrian Dix

Canadian policing organization calls for decriminalization of simple illicit drug possession

Canadian Association of Chiefs of Police want policing focus of opioid crisis to be replaced with a health one

Filing deadline in RCMP sexual-harassment class-action extended due to COVID-19

Plaintiffs now have until January 2021 to submit claims for up to $222,000

Jamie Bacon pleads guilty to charge in Surrey Six case

The plea brings an end to a complex legal case that has spanned more than a decade

Hefty undeclared driver charges piling up, ICBC warns customers

Average extra penalty $2,971 after an at-fault accident

B.C. appeals judge’s decision to leave three clubhouses in Hells Angels hands

The province has filed two notices of appeal related to the B.C. Supreme Court decision

Conservation officers relocate Spirit bear known to roam northwestern B.C.

Bear roamed valley north of Terrace for many years

B.C. premier applauds call to decriminalize drug possession

Police shouldn’t struggle with health issues, Horgan says

Most Read