The Crab Nebula
Stunning humans since 1054. (Vol. 2; Issue 40)
Welcome aboard The Bus!
The Stop
On 4 July 1054, a nearby star - only 6,500 light years1 from Earth - exploded in a supernova. The rapidly-expanding remains of the star - a sun around ten times the mass of our own - formed the Crab Nebula, one of the ‘most famous and beautiful sights in the heavens.’ The precise date of this event - which was visible in daylight for 23 days and at night remained visible to the naked eye for two years - is known because of the records kept by Chinese astronomers. Though there are ’no records of its observation at the time by Europeans,’ this spectacular event was recorded by another great civilisation: the Chacoans.2
Between 900 and 1150 CE, the Chacoans built a ‘series of vast stone structures’ in the Chaco Canyon in New Mexico. These buildings - the largest human-built structures in North America until the 19th century - contain hundreds and hundreds of rooms. Rather than permanent residences, archaeological evidence indicates they were ‘largely ceremonial.’ The architecture of the canyon, including a ‘precisely aligned and complex road system,’ appears to have been designed to both symbolise and establish its position as not only the ‘centre of local culture, commerce and religion, but also as the centre of the Universe.’ The structures align with the points of the compass and also with important events in the solar year such as the summer and winter solstices. Though there is controversy over whether all of the ‘claimed alignments’ were intentional, the Chacoans are known to have been ‘keen observers of the skies’ and to have possessed an ‘intricate and advanced cosmology.’
The heart of a great civilisation that was once connected to ‘dozens’ of other regional settlements by around 400 miles of engineered road, Chaco Canyon contains many examples of rock art. Both petroglyphs (images carved into a rock surface) and pictographs (images painted onto a rock surface) were used to visually ‘transmit ideas and beliefs.’ Though most are either geometric designs or depictions of stick figures, stylised humans or animals, there is one pictograph that appears to record the emergence of the nebula. On the ‘underside of a rocky overhang next to a dry riverbed,’ there is a painting of a handprint, a crescent moon and a bright star (fig. 1). It is known this was made at some time around the event of 1054, but the ‘best evidence’ that it’s a record of the supernova is its alignment. Every 18.5 years, the Moon and Earth move into the same position they were in over the nights around 4 July 1054. During this time, while positioned beside the painting, the ‘Moon will pass by the position in the sky indicated by the handprint [and] at that moment, to the left of the Moon, exactly as depicted in the painting,’ an observer will see the Crab Nebula.
The Crab Nebula is one of the most intensely studied nebulas, largely because it is one of the ‘few astronomical objects from which radiation has been detected over the entire measurable spectrum.’ After just 1000 years, the cloud of glowing gas is already 11 light years across and is still expanding at around 1,100 km (700 miles) per second. At its heart is the collapsed remnant of the star that went supernova, a rapidly-rotating neutron star3 which ‘flashes in radio, visible, X-ray, and gamma-ray wavelengths’ at a precise rate of 30.2 times per second. Known as the Crab pulsar, this unique neutron star provides the energy that allows the nebula to glow.
The Detour
Today’s Detour is In the Shadow (7:47), a ‘fantasy film noir with shadows.’ Written, edited and directed by Fabrice Mathieu, it is a collage created by editing together extracts from famous examples of film noir to create a completely new story. It’s excellent.
The Recommendation
Today’s recommendation is Moon (2009). Directed by Duncan Jones4 and starring Sam Rockwell, the film is a science fiction drama set in a mining facility on the far side of the Moon. The facility provides the Earth with the clean energy source helium-3,5 and is automated to the degree that only a single human is required to maintain the operation. This solitary person is Samuel Bell, who is nearing the end of his three-year work contract when he begins suffering hallucinations - one of which causes him to crash his lunar rover while recovering a helium-3 canister from a harvester. Awakening in the base infirmary with no memory of the accident, Sam grows suspicious and, after travelling to the crashed rover and finding his unconscious doppelgänger, the mystery grows deeper and more sinister. Based on a story by Jones, Moon won the BAFTA Award for Outstanding Debut by a British Writer, Director or Producer along with several others and has a 90% rating on Rotten Tomatoes. Give it a go - if you’re at all into thoughtful science fiction, it’s worth a watch.
Moon streams on various platforms.
The Sounds
Today’s playlist is a selection of five great tracks that are linked only by the fact they were popular in 2009, the date of Moon’s release: ‘Uprising’ (Muse, 2009), ‘Fire’ (Kasabian, 2009), ‘(If You’re Wondering If I Want You To) I Want You To’ (Weezer, 2009), ‘Empire State of Mind’ (Jay-Z) and ‘Fireflies’ (Owl City, 2009).
The Thought
Today’s Thought is from Jean-Paul Sartre:6
‘Every existing thing is born without reason, prolongs itself out of weakness, and dies by chance.’
If you have a thought on this Thought - or any part of today’s issue - please leave a comment below:
And that’s the end of this Stop - I hope you enjoyed the diversion!
Thanks to everyone who subscribes - your interest and support is truly appreciated. If you like The Bus, please SHARE it with a friend or two.
If you haven’t climbed aboard The Bus, please do!
Until the next Stop …
In astronomy, a light-year is the ‘distance travelled by light moving in a vacuum in the course of one year, at its accepted velocity of 299,792,458 metres per second (186,282 miles per second).’ A light-year equals about 9.46 x 10^12 km (5.88 x 10^12 miles). For a good explanation which puts these distances into perspective, see: How Far is a Light-Year?
Sources for today’s Stop include: Light-year (Britannica), Crab Nebula (Britannica), Chaco Culture (Britannica), Chacoans (NPS) and Cox, Brian and Andrew Cohen. Wonders of the Universe. London: Harper Collins, 2011.
A neutron star - ‘truly amongst the strangest worlds in the Universe’ - are fascinating. I’m looking at making this a future Bus Stop, but in the meantime, see: Neutron Star (Britannica).
Fun fact: Jones (born Duncan Zowie Haywood Jones) is the only child of English musician David Bowie and his first wife Angela Barnett. He’s also directed Source Code (2011), Warcraft (2016) and Mute (2018).
Helium-3 is real and is evidently not only all over the surface of the moon, but there is serious consideration about how to mine it and send it to Earth. For an interesting article, see: Helium-3 Mining on the Moon (European Space Agency).
Catching up on some back issues I hadn't read yet and really like this pearl about the Crab Nebula observation seemingly documented in Chaco. I have read some interesting archaeological observations about Chaco Canyon and its creators but had not read about this. If you want to learn more about the "Anasazi" culture a great book is Craig Childs' House of Rain. He tracks the civilization and their movement around the southwest - starting in Chaco Canyon.
Excellent collection of things combined in a way that makes you appreciate life from a birds eye view. Thanks