Tea at Trianon: The Sands of Mars

John Wilson Croker on Marie-Antoinette

"We have followed the history of Marie Antoinette with the greatest diligence and scrupulosity. We have lived in those times. We have talked with some of her friends and some of her enemies; we have read, certainly not all, but hundreds of the libels written against her; and we have, in short, examined her life with– if we may be allowed to say so of ourselves– something of the accuracy of contemporaries, the diligence of inquirers, and the impartiality of historians, all combined; and we feel it our duty to declare, in as a solemn a manner as literature admits of, our well-matured opinion that every reproach against the morals of the queen was a gross calumny– that she was, as we have said, one of the purest of human beings."

~from History of the Guillotine by John Wilson Croker, 1844

Edmund Burke on Marie-Antoinette

"It is now sixteen or seventeen years since I saw the queen of France, then dauphiness, at Versailles; and surely there never lighted on this orb, which she hardly seemed to touch, a more delightful vision. I saw her just above the horizon, decorating and cheering the elevated sphere she had just begun to move in, glittering like a morning star full of life and splendor and joy. Oh, what a revolution....Little did I dream that I should have lived to see such disasters fall upon her, in a nation of gallant men, in a nation of men of honor and of cavaliers! I thought ten thousand swords must have leaped from their scabbards, to avenge even a look which threatened her with insult. But the age of chivalry is gone; that of sophisters, economists, and calculators has succeeded...."

~Edmund Burke, October 1790

Saturday, June 29, 2019

The Sands of Mars

From Archaeology News Network:

In the most detailed analysis of how sands move around on Mars, a team of planetary scientists led by Matthew Chojnacki at the University of Arizona Lunar and Planetary Lab set out to uncover the conditions that govern sand movement on Mars and how they differ from those on Earth.

The results, published in the current issue of the journal Geology, reveal that processes not involved in controlling sand movement on Earth play major roles on Mars, especially large-scale features on the landscape and differences in landform surface temperature.

"Because there are large sand dunes found in distinct regions of Mars, those are good places to look for changes," said Chojnacki, associate staff scientist at the UA and lead author of the paper, "Boundary conditions controls on the high-sand-flux regions of Mars." "If you don't have sand moving around, that means the surface is just sitting there, getting bombarded by ultraviolet and gamma radiation that would destroy complex molecules and any ancient Martian biosignatures."

Compared to Earth's atmosphere, the Martian atmosphere is so thin its average pressure on the surface is a mere 0.6 percent of our planet's air pressure at sea level. Consequently, sediments on the Martian surface move more slowly than their Earthly counterparts.

The Martian dunes observed in this study ranged from 6 to 400 feet tall and were found to creep along at a fairly uniform average speed of two feet per Earth year. For comparison, some of the faster terrestrial sand dunes on Earth, such as those in North Africa, migrate at 100 feet per year. (Read more.)