1249: Meteor Showers
Title text: Remember, meteors always hit the tallest object around.
This comic spoofs the way that astronomical events are often reported in the mass media — events are often tagged with undeserved superlatives or described as being more dramatic than they actually are. In some cases, outright misinformation is spread. This phenomenon occurs in part by the result of over-eager scientists, but mostly because of journalists with no deeper knowledge on the subject they write about.
Meteor showers typically occur regularly each year. It always happens at the same days because the Earth is crossing the dust path of a particular comet. Sometimes meteor showers are in fact likely to be relatively spectacular when the peak of the shower occurs while your part of the world is in darkness and there is little moonlight. However, even in these cases it must be understood that there is nothing unusual about the meteor shower itself. The shower just consist of small particles at a size about roughly one millimeter, only the high speed is the reason that is can be seen from Earth's surface. The names of the showers refer to the star constellation where they visually belong to.
Most of the meteor showers listed in the comic are real, but some are made up (and indicated as such below).
- Quadrantids - January 4th - Bring pets inside during peak activity
- Keeping pets inside may be reasonable on days when fireworks are let off in the beginning of a new year, no regular meteor shower poses much danger to pets.
- (made-up) Tricuspids - January 21st - Not viewable in region 2 countries
- Apparently a play on the tricuspid valve in mammalian hearts, or possibly on bicuspid teeth. The mention of "Region 2" is a reference to region locking, a digital rights management (DRM) scheme intended to restrict media to certain areas. DRM of course does not apply to natural events. But ironically, meteor showers are also geographically restricted, and the visible area might roughly coincide with a DRM region. Further irony is that "Region 2" is actually Europe, Middle East, Egypt, Japan, South Africa, Swaziland, Lesotho, Greenland, French Overseas departments and territories, meaning that it's not strictly geographical.
- Since indoor lights and window glass make them harder to see, it would take a very bright meteor to be visible without going outside.
- (made-up) Beta Aquariids - February 10th - Inverted shower converges toward Aquarius instead of radiating away
- This fictional shower would collect shooting stars into the origin to prepare for the real Eta Aquariids meteor shower associated with Haley's comet and diverging from Eta Aquarii in Aquarius; the real shower peaks around May 6th.
- Due to perspective, meteor showers appear to radiate outwards from a certain point in the sky. Meteor showers may be seen to converge on a point on the opposite side of the sky, but with the earth in the way there would only be a few visible going past the edge, seen as nearly parallel streaks overhead, so the convergence point would hardly be notable.
- (made-up) Chelyabids - February 15th - Only one meteor per shower, but it's big.
- A reference to the February 15, 2013, Chelyabinsk meteor whose explosion shattered windows within a large radius.
- Lyrids - April 22nd - Meteors sometimes scream
- A meteor large enough to reach the lower atmosphere could produce sound audible to observers on the ground, but this is very unusual.
- Daytime Zeta Perseids - June 9th - Likely a NASA hoax
- This shower is mostly observed via its effects on radio and TV signals, and therefore a good target for conspiracy theorists responding to June's Invisible Meteors - NASA Science
- June Boötids - June 27th - 50/50 mix of meteors and shooting stars
- The "50/50 mix of meteors and shooting stars" is a joke, as "meteor" and "shooting star" are synonymous.
- Southern Delta Aquariids - July 19th - Meteors very bright, but stationary
- This is saying that they are indistinguishable from stars, or that the stars themselves are actually meteors.
- (made-up) Dromaeosaurids - July 22nd - Fast, highly intelligent, can open doors
- Dromaeosaurids are a family of dinosaurs containing the genus Velociraptor, well-known from the movie Jurassic Park in which they are presented as a deadly menace, fast and especially intelligent to the point of understanding how to open a door; this representation of Velociraptors is a recurrent topic in xkcd. When the comic was originally published, the date listed for this shower was June 12th, the date of the velociraptor attacks in the movie.
- Perseids - August 12th - Instead of falling from sky, meteors erupt from ground
- ??? (apart from the fact that erupting from the ground is the funny inverse of falling from the sky, what meteor always do)
- (made-up) Tau Pyramids - August 15th - Visible even when eyes are closed
- Probably a reference to Pyramidal cells, a type of neuron. The "tau" reference has two possibilities. The "visible even when eyes are closed" could refer to the Tau particle, a heavy sibling of the electron. When they traveled outside of Earth's magnetosphere on their way to the Moon, Apollo astronauts saw flashes of light about every three minutes even with their eyes closed; these were caused by high energy particles (cosmic rays) penetrating their eyes and brain. The other possibility is that it refers to Tau protein, a normal structural protein within brain neurons. In Alzheimer's Disease, abnormal Tau proteins can aggregate within pyramidal cells to form insoluble skeins. The number of these "neurofibrillary tangles" roughly correlate with the severity of cognitive impairment.
- Draconids - October 8th - Very slow, but follow you if you run
- ??? (maybe something to do with the fact that "draconids" etymologically means "of the dragon", which could make for a fearsome meteor shower)
- Orionids - October 21st - Entire shower happens at once
- As noted in comic 1020, the Orion constellation (in which the Orionids are located) has a 'dong'. Possibly a joke about a "golden" shower. Maybe.
- Leonids - November 17th - In 1966, unusually active Leonid shower killed God
- There was a very active Leonid shower (a "meteor storm") in 1966, and a precursor to it in 1965. The article Is God Dead? was published in Time Magazine on April 8 of 1966. Perhaps this suggests that the meteors killed God earlier in the year when they and He were further out in the solar system?
- Geminids - December 13th - Can be deflected with tennis rackets
- ??? (apart from the simple funny idea of deflecting a meteor with a tennis racket)
The title text refers to the folk wisdom that lightning strikes the tallest thing around. Randall expressed frustration over how "maddeningly inexact" that statement is, and elaborated on the problem mathematically, on his what if? blog post on lightning.
|The xkcd guide to meteor showers|
|Quadrantids||January 4th||Bring pets inside during peak activity|
|Tricuspids||January 21st||Not viewable in region 2 countries|
|Centaurids||February 6th||Too faint to see without going outside|
|Beta Aquariids||February 10th||Inverted shower converges toward Aquarius instead of radiating away|
|Chelyabids||February 15th||Only one meteor per shower, but it's big.|
|Lyrids||April 22nd||Meteors sometimes scream|
|Daytime Zeta Perseids||June 9th||Likely a NASA hoax|
|June Boötids||June 27th||50/50 mix of meteors and shooting stars|
|Southern Delta Aquariids||July 19th||Meteors very bright, but stationary|
|Dromaeosaurids||July 22th||Fast, highly intelligent, can open doors|
|Perseids||August 12th||Instead of falling from sky, meteors erupt from ground|
|Tau Pyramids||August 15th||Visible even when eyes are closed|
|Draconids||October 8th||Very slow, but follow you if you run|
|Orionids||October 21st||Entire shower happens at once|
|Leonids||November 17th||In 1966, unusually active Leonid shower killed God|
|Geminids||December 13th||Can be deflected with tennis rackets|