Tea at Trianon: Ancient Mars' Rivers and Lakes

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

Thursday, June 3, 2021

Ancient Mars' Rivers and Lakes

From Space:

Cloudy skies may have allowed water to flow on Mars long ago. Though the Red Planet is a frigid desert today, around four billion years ago it hosted relatively long-lived lakes and river systems, as observations by NASA's Curiosity rover and other Mars robots have shown.

Mars' atmosphere was much thicker back then, which helped to keep liquid surface water from boiling away. However, it remains unclear how that water could have been liquid in the first place; the sun was about 30% dimmer during that ancient epoch than it is today, so the Martian surface should seemingly have been a permanent winter wonderland. A new study may help to solve this puzzle. A thin layer of icy clouds high in the Martian atmosphere could have provided a greenhouse effect, warming the planet for long stretches, researchers found.

"There's been an embarrassing disconnect between our evidence and our ability to explain it in terms of physics and chemistry," lead author Edwin Kite, a planetary scientist at the University of Chicago, said in a statement. "This hypothesis goes a long way toward closing that gap."

This cloud idea was first proposed nearly a decade ago but fell out of favor because "it was argued that it would only work if the clouds had implausible properties," Kite said. For example, previous modeling work suggested that water would have had to persist for unrealistically long periods in the Martian atmosphere for the clouds to do their warming work. However, the new modeling work by Kite and his colleagues indicates that wispy but warming clouds could indeed have formed high above the planet, trapping enough heat for liquid water to persist on the surface — but only if certain conditions were met.(Read more.)