Dear PT5
It turns out six of your siblings did a flyby of Earth last week. Of course this being space, which, like the man says, is relaly really big, ‘flyby’ does a lot of heavy lifting. The biggest, 2002 NV16 (NV to it’s friends, ‘Sir, this is a Class M world’ to Earth) was 4.5 million kilometres or so way when it passed. Which is fortunate given it was somewhere around 580 feet long. The others, 2024 TP17, 2024 TR6 (He’s the funny one), 2021 UE2 and 2015 HM1 are all smaller, and passed at different ranges but still, a flyby is still a flyby. We learn a lot about how the universe works from moments like this, and also got that rollercoaster frisson of relief at seeing the bad thing, identifying the bad thing and realising that this time the bad thing is passing us by. But even when they miss us, the ripples get really interesting.
This is Meteor Crator in Arizona. About 50,000 years ago a meteorite came to a sudden terrestrial stop at the bottom there. The first people to figure that out were a mining engineer called Daniel Barringer and his partner Benjamin Chew Tilghman. In 1903 the two men conducted land surveys, documented their findings and drew what was, at the time, an incredible conclusion: the crater was caused by the impact of a rock falling from space. It was good science but it was early, planetary science still accreting itself together much like the planets themselves do. The two men were derided and Barringer died in 1929, decades before his work was vindicated. Chew Tilghman’s fate is a little more obfuscated. There is a Benjamin Chew Tilghman who invented sandblasting, moved to England and became an industrial leader but he died in 1901. Another story, glimpsed as it passes by in the night.
Barringer and Tilghman’s work was vindicated in the end. Eugene M. Shoemaker and Edward T Chao identified Shocked Quartz, or coesite at Meteor Crater in 1960. This splendidly named mineral is a form of Quart formed under very high pressure and moderately high temperature. It doesn’t tend to occur naturally but it’s at Meteor Crater. Shoemaker and the team confirmed Barringer and Tilghman’s theory and the crater was named Barringer Crater to acknowledge this. The fact it’s still called Meteor Crater is understandable but I like to think of it as having a triple barrelled name. Barringer Chew Tilghman Meteor Crater. Meteor for short.
Shoemaker would go on to help train Apollo astronauts at Meteor Crater, due to it’s similarities to the lunar surface. He also co-discovered Comet Shoemaker-Levy in 1993 with his wife, Carolyn. She discovered 32 comets, more than 500 asteroids and came to this crunchiest of sciences from a history, political science and English literature background. She had a bone dry sense of humour as demonstrated in this quote from David H. Levy’s profile of her in Nature:
Carolyn never really considered herself a scientist, although she absorbed a large amount of geology and astronomy from her husband. She was a forthright person, gifted with inordinate patience and a fine sense of humour. Before the Jupiter impacts, a reporter asked her what would happen if all the comet’s fragments were to hit Earth instead. “We would all die,” she answered. The interviewer explained that this was for a children’s programme, then posed the question again. Carolyn’s second answer: “We would all be very uncomfortable.”
I like to think she’d have got on well with Caroline Lucretia Herschel and Maria Margarethe Kirch. Herschel, whose brother is, because of course he is, the more famous astronomer was a successful musician prior to joining the family business. She was scathing in her description of her work, and history credited her as nothing more than Herschel’s record keeper for a long time. Herschel constantly fought for his sister’s achievements to be recognised and it actually ended up paying off. Literally. King George III gave her an annual salary in recognition of her work and she ebcame the first woman in England to be given an official government position and the first woman on Earth to be paid to work as an astronomer. She was also credited for a long time as being the first woman to discover a comet. I remember seeing a piece of her correspondence which included the incredible line:
‘I’ve discovered a comet by mistake’
And I can’t for the life of me track it down. In tracking down Caroline though, I found out she wasn’t the first! Maria Margarethe Kirch, the wife of Gottfried Kirch the Astronomer Royal of Berlin discovered a comet in 1702, forty eight years before Caroline Herschel was born. However, the discovery was published by Gottfried and he was acknowledged as the discoverer. It took eight years but he did acknowledge the error and credit her as the discoverer in 1719 but it never took and she was never officially credited.
Eugene Shoemaker was killed in 1997 in a head on car accident in Australia. Carolyn was seriously injured in the same accident but survived and continued to work until at least 2002. She died in 2021 and is credited with discovering 32 comets and over 500 asteroids.
One flyby, which leads me to research one crater which leads to six lives in science, three of them obfuscated by the reputations and practices of their time but shining too brightly to ignore, Everything connected by the desire to look up, to find out, to see more and to tell others what we’ve discovered. I love that. I also love that some of Eugene Shoemaker’s ashes, with NASA’s permission, are interred on the Moon The brass foil of his memorial capulse is inscribed with images of Comet Hale-Bopp, the last comet Carolyn and he observed together, this quotation from Romeo & Juliet:
And, when he shall die
Take him and cut him out in little stars
And he will make the face of heaven so fine
That all the world will be in love with night
And pay no worship to the garish sun.
And an image of Barringer Crater.
Have a great week, PT5
References
Asteroid Flyby
- https://www.indiatoday.in/science/story/earth-in-the-firing-line-of-asteroids-six-space-rocks-to-come-close-on-october-24-2621836-2024-10-23
- https://www.livescience.com/space/asteroids/potentially-hazardous-asteroid-the-size-of-a-skyscraper-will-miss-earth-tuesday
- JPL’s Small Object Database
- https://www.spacereference.org/
Barringer Crater
- https://www.atlasobscura.com/places/meteor-crater
- https://barringercrater.com/the-crater
- https://en.wikipedia.org/wiki/Coesite
Scientists
- https://en.wikipedia.org/wiki/Daniel_Barringer_(geologist)
- https://en.wikipedia.org/wiki/Benjamin_Chew_Tilghman
- https://en.wikipedia.org/wiki/Edward_C._T._Chao
- https://en.wikipedia.org/wiki/Eugene_Merle_Shoemaker
- https://en.wikipedia.org/wiki/Carolyn_S._Shoemaker
- https://en.wikipedia.org/wiki/Caroline_Herschel
- https://dornsife.usc.edu/news/stories/caroline-herschelfirst-female-astronomer/
- https://en.wikipedia.org/wiki/Maria_Margaretha_Kirch
- https://thonyc.wordpress.com/2015/08/02/sorry-caroline-but-maria-got-there-first/