Saturday, December 26, 2009

(259) Shoemakers impacts: craters on the Earth and the Moon and comets on Jupiter

In the earliest hours of Boxing Day 2009 I was looking up details of St. Crispin and his patronage of shoemakers.

I was moved to do so because of a lingering interest generated by my £250,000 question on Who Wants to be A Millionaire? some four years earlier (see Entry 224).

I then thought about looking up more details of the astronomer Shoemaker, after whom, I understood, the comet Shoemaker-Levy 9 had been named.

I discovered facts about him that surprised me by their significances, not least in the context of the next question I was to face on the show; the one which stopped me -
(Which of these astronauts has never set foot on the moon?) - and also relating to Entry .

Eugene Merle Shoemaker (1928 – 1997) was best known as an astronomer.
But he began, I learned, as a geologist and studied the impact dynamics of Barringer Meteor Crater, Arizona for his Ph.D (1960).

In 1993, he, together with his wife Carolyn Shoemaker and David Levy, co-discovered Comet Shoemaker-Levy 9. This provided the unique opportunity to observe the planetary impact of a comet when it collided with Jupiter in 1994. It caused a massive "scar" on the face of Jupiter. Most scientists were dubious of whether there would even be any evident markings on the planet.

So -
a) Gene married Carolyn Spellman in 1951. A visit to Meteor Crater the following year set him toward the view that both it and lunar craters were due to asteroidal impacts. In 1956 he tried to interest the United States Geological Survey in the construction of a geological map of the moon. He then did seminal research on the mechanics of meteorite impacts, awarded a master's degree in 1954.
Shoemaker was the first to show that Barringer Crater was formed not by volcanic activity but by an extraterrestrial impact. Hence it is now Meteor Crater.
b) He studied the impact dynamics of Barringer Meteor Crater for his Ph.D in the year of my birth (1960).
He did more than any other person to advance the idea that sudden geologic changes can arise from asteroid strikes and that these are common over geologic time periods.
Previously, astroblemes were thought to be remnants of extinct volcanoes – even on the Moon.
c) He was a pioneer in astrogeology and prominently involved in the Lunar Ranger Moon missions,
which showed that the Moon is covered with impact craters of many sizes.
From an early age he was passionate about going to the moon and became a candidate for an Apollo moon flight. Set to be the first geologist to walk on the Moon, diagnosis of Addison's disease in 1963 prevented him.
d) "Which of these astronauts has never set foot on the moon?"
Shoemaker, an astronaut intended to set foot there, didn´t.
Walking on the moon requires careful preparation and equipment.
You may not do it barefoot.
He was involved in training astronauts, e.g. during field trips to Meteor Crater itself and at Sunset Crater, Arizona.
e) Shoemaker began as a terrestrial geologist, suggesting that craters were formed by meteorite impacts - a very innovative idea.

He then suggested that lunar craters were too.

When the USGS Center of Astrogeology was founded in Flagstaff in 1965, he was appointed its chief scientist and organized the geological activities planned for the lunar landings.

In 1969 he became interested in extending his geological knowledge of the formation and distribution of terrestrial and lunar impact craters to the study of the objects that formed them. His search resulted in the discovery of several such families, including the Apollo asteroids.
In 1983 the first of the record 32 comets associated with the Shoemaker name was discovered. By the time the program ended it had produced 40 of the--now--417 known Amor, Apollo and Aten asteroids (the orbits of this last group being smaller than that of the earth).
The Shoemakers ensured that Palomar is likely to remain the leading site for the discovery of asteroids, having found more than 13% of those numbered.
A few months before the Shoemaker program ended came its "defining moment", with Gene receiving the thrill of his lifetime when 20 components of one of his comets crashed into Jupiter with astounding results.

So he ended his scientific career searching for the extraterrestrial objects that caused craters.

Above all, he was truly the "father" of the science of near-earth objects, to the discovery and study of which The Spaceguard Foundation is dedicated.
He also spent his later years searching for meteor craters. During one such expedition he died in a car crash in Australia.
He was killed instantaneously by a violent impact when investigating the sites of violent impacts, a tragic irony that would not have been lost on his accompanying wife and co-explorer of the terrestrial and astronomical, Carolyn.
f) On July 31, 1999, some of his ashes were carried to the Moon by the Lunar Prospector space probe in a capsule.
Shoemaker's memorial capsule is inscribed with images of Comet Hale-Bopp, the Barringer Crater, and a quotation from Romeo and 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."

My wife helped me by phone to answer the Shoemakers question.

Shoemaker is the only person buried on the moon.
g) Although these insights came to me in the early hours of Boxing Day 2009, in Shoemaker´s homeland it would still have been Christmas Day.
... ... ...
To walk on the moon the first prerequisite, more important than health, piloting ability, intelligence or any other quality or attribute, is simply the demonstration that one really WANTS to walk there.

(As I changed the last two words of that sentence from "do it" to "walk there" at 3:48 P.M. on Jan 29th 2010 my wife called out to me to ask if I had seen what Catherine Warwick had just added at a Facebook thread that Fiona had started -

It was a link to this -

Underwater chess Curacao
Dutch chessmasters 'Hans Böhm' and 'Robin Swinkels' take up a chess match 4 meters below sealevel having stingrays and fish as their specta
Ayer a las 22:19

Fiona Pitt-kethley
Wonderful film. Made my day. My husband has met one of the guys
Ayer a las 22:26
Catherine Warwick
Great fun. Now all we need is chess on the MoonHace 37 minutos
... ... ...
And not just to ponder on it or gaze at it or dream about it or be hanger-on to a moonwalker.

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