Wishing Star Scouting · 12:57pm Dec 24th, 2022
At this time of year, there is a tradition of planetarium shows about possible astronomical explanations for the story of the Star of Bethlehem, which guided the Magi to the baby Jesus. Scholars have been pondering this for centuries. It’s a fun question to ponder as it mixes biblical scripture, history, astrophysics, and lets us talk about comets, novae, supernovae, planetary conjunctions, along with ancient astronomy from many cultures. See for example this BBC documentary.
This post is analysing the Winter Wishday Wishing Star in the same way. What is the astronomical phenomenon behind this bright light? This beacon of hope bringing joy to a pony world that Sunny Starscout has redeemed from sin.
Sunny implies that the star is an established earth pony Winter Wishday tradition, so we assume that it is an annual phenomenon. She predicts its arrival to the second. At that second, we see a star with a pink tail, surrounded by a halo, move quickly across the sky. It abruptly flares up much brighter, loses its tail, and stops moving. This triggers the Unity Crystals / Brighthouse Prisbeam Projector to display the cutie mark images.
We see a similar thing in Under the Mistytoe, but with a few differences: the comet appears in the middle of the sky at Sunny’s countdown; it moves in the opposite direction; its transformation seems to be triggered by a conjunction of its path, the Prisbeam, and cutie mark magic. The ponies also view it from outside instead of the Brighthouse roof.
These discrepancies just tell us that we should view the episodes as different artists interpretations of what happened. We cannot rely on these images being completely correct any more than we should believe the story in the Book of Matthew is gospel truth. So, there's no need to worry too much if a detail in the observational evidence doesn’t fit your favourite theory.
All sources agree that the wishing star was pretty cool. But what was it?
Star
The simplest explanation is that it is just a star. One of the many distant luminous objects that fill the night sky, appearing fixed relative to other stars, and moving with them as the planet rotates. The rotation of the stars shifts through the year, such that a given bright star could be visible right above Maretime Bay at midnight on the Winter solstice (or any other night you chose to designate). Such a star could acquire a great significance in the local culture. Especially in a seaside town, where sailors would use the stars to guide them home.
The pink tail and rainbow lasers are an artistic embellishment. You could attribute the halo to ice crystals in the atmosphere. Altogether a plausible explanation, but a bit boring.
Comet
It has a tail. Everyone knows that comets have tails. They are icy rocks that spend most of their time in the cold dark region far out in the solar system, but they have highly eccentric elliptical orbits and are periodically catapulted around the sun. As they heat up when close to the sun, gas and dust stream out and are blown by the solar wind into a tail.
Comets are predicable. However, the wishing-star-comet theory has some problems. Even short period comets don’t come back very often (Halley’s comet has a period of 75 years). A comet with an orbital period of one year would be close to the sun all the time and soon lose its tail and turn into an asteroid. Comets are also visible for months and don’t move across the sky anywhere near as fast as what we see.
Satellite
One thing that we can see in our night sky that moves fast is the International Space Station. In a low orbit, it zips around every two hours. The way Sunny checks the star position on her phone was a bit like how ISS fans keep an eye on the Heavens Above app, to make sure they don’t miss the next pass.
Could the wishing star be an artificial satellite? Maybe it was created by Twilight Sparkle using her moon-raising powers (see: Twilight’s Sputnik). You can imagine setting it up on an eccentric year-long orbit around the Earth, such that it reaches its perigee, closest to the Earth, every Winter Wishday. If this were as low as the ISS, it would shine brightly at this point, but for most of the year it would be too far away to see. Such an orbit would likely be unstable due to the influence of the sun and moon and need regular adjustments, but nothing a smart alicorn princess would not foresee.
With a bit of skill, she could let it rotate so that its surface reflects maximum sunlight, causing it to flare up in brightness, just as ponies are all watching below (satellite flare). You can’t, however, explain the pink tail, or why it stops moving, without invoking a bit of magic.
If you want a Sci-Fi story idea, maybe this is Twilight’s spaceship. She could be onboard, in a state of suspended animation. Every year, when nearest to Equestria, it beams down some Friendship Magic to help ponies out and make a few wishes come true.
Laser guide star
So far, we have treated the Wishing star as an astronomical phenomenon that Sunny can predict but not control. We should consider the possibility that she is playing a more active role. Her alicorn magic does not seem to be yet developed enough to allow full sun and moon raising powers, but as shooting Prisbeams into the sky is an everyday thing, perhaps she has learnt a thing or two about laser stars.
A Laser Guide Star is created by shining a 589.2 nanometre laser beam up in the sky. This excites sodium atoms in the mesosphere (90km up) so they shine as an artificial star. They are used by big observatories to generate light in dark patches on the sky to run adaptive optics systems to correct the blurring of starlight by the atmosphere.
With such technology, Sunny could create stars that appear, move, and change brightness, in order to impress her friends. But this feels a bit like cheating.
There are my theories. Take your pick, or post your own below. And Cheery Wishday / Warm Wishiehoof / Joyous Wishentine / Happy Hearth’s Warming / Merry Christmas / Happy Holidays everyone.
And unlike the Star of Bethlehem, you don't need to.
Laser guide stars! How fascinating!
I wonder if there's a theoretical ceiling on their brightness? (In a usual astronomical application, the laser's power is maybe ten to twenty watts, and the 'star's' brightness might be tenth magnitude, which is so dim it would require a telescope to see. https://www.gemini.edu/node/128 )
Also, I wonder why they aren't called 'laser guide planets,' or 'laser guide planetoids,' or 'laser guide satellites,' since their physical nature isn't any more starlike than those other silly names.)
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The limit on brightness comes from the astronomers telling you to keep the light pollution down. They don't really like using lasers. They prefer using normal stars, but there aren't enough sufficiently bright ones to cover all the sky.
Maybe the bubble of all the magic pulled out of new equestria forms a bubble approximately a light year equivalent in radius, and the Star is the refocused reflection of the triggering event passing through again?
About the Star of Bethlehem, we have 2 problems:
* As seen from Earth, a particular visible planet occulting a particular visible star might only happen every few thousand years, but with all of the visible stars and planets, we have someteen or umpteen (more than a dozen (12) but less than a score (20)) potential candidates annually. Someone assuming that Denis The Small was more right than wrong but putting in a fudge-factor of either ± or ∓ 1 decade, has hundreds of possible candidates.