Starship Asterisk*

orin stepanek wrote:
Right now; water seems to be a good explanation for the dark streaks.

APOD Robot wrote:Mars might harbor some sort of water-dependent life.

jetsam wrote:
Soon we will stop laughing at Lowell.

http://en.wikipedia.org/wiki/Giovanni_Schiaparelli wrote:

Clear day at Pulkovo Observatory in 1839

Don Giovanni Schiaparelli

<<Giovanni Virginio Schiaparelli (March 14, 1835, Savigliano – July 4, 1910) was an Italian astronomer and science historian. He studied at the University of Turin and Berlin Observatory. In 1859-1860 he worked in Pulkovo Observatory and then worked for over forty years at Brera Observatory.

Among Schiaparelli's contributions are his telescopic observations of Mars. In his initial observations, he named the "seas" and "continents" of Mars. During the planet's "Great Opposition" of 1877, he observed a dense network of linear structures on the surface of Mars which he called "canali" in Italian, meaning "channels" but the term was mistranslated into English as "canals".

While the term "canals" indicates an artificial construction, the term "channels" connotes that the observed features were natural configurations of the planetary surface. From the incorrect translation into the term "canals", various assumptions were made about life on Mars; as these assumptions were popularized, the "canals" of Mars became famous, giving rise to waves of hypotheses, speculation, and folklore about the possibility of intelligent life on Mars, the Martians. Among the most fervent supporters of the artificial-canal hypothesis was the American astronomer Percival Lowell, who spent much of his life trying to prove the existence of intelligent life on the red planet. After Lowell's death in 1916, astronomers developed a consensus against the canal hypothesis, but the popular concept of Martian canals excavated by intelligent Martians remained in the public mind for the first half of the 20th century, and inspired a corpus of works of classic science fiction.

Later, with notable thanks to the observations of the Italian astronomer Vicenzo Cerulli, scientists came to the conclusion that the famous channels were actually mere optical illusions. The last popular speculations about canals were finally put to rest during the spaceflight era beginning in the 1960s, when visiting spacecraft such as Mariner 4 photographed the surface with much higher resolution than Earth-based telescopes, confirming that there are no structures resembling "canals".

In his book "Life on Mars", Schiaparelli wrote: "Rather than true channels in a form familiar to us, we must imagine depressions in the soil that are not very deep, extended in a straight direction for thousands of miles, over a width of 100, 200 kilometers and maybe more. I have already pointed out that, in the absence of rain on Mars, these channels are probably the main mechanism by which the water (and with it organic life) can spread on the dry surface of the planet.">>

http://www.nasa.gov/mission_pages/MRO/news/mro20110804.html wrote:
Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars' southern hemisphere. "The best explanation for these observations so far is the flow of briny water,"

The features imaged are only about 0.5 to 5 meters wide, with lengths up to hundreds of meters. The width is much narrower than previously reported gullies on Martian slopes. However, some of those locations display more than 1,000 individual flows. Also, while gullies are abundant on cold, pole-facing slopes, these dark flows are on warmer, equator-facing slopes.

When researchers checked flow-marked slopes with the orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), no sign of water appeared. The features may quickly dry on the surface or could be shallow subsurface flows. "The flows are not dark because of being wet," McEwen said. "They are dark for some other reason."

http://en.wikipedia.org/wiki/Cannoli wrote:

The dark, finger-like features imaged
are only about 0.2 to 1 centimeters wide,
with lengths up to 4 centimeters.
"The flows are not dark because of being wet,"
"They are dark for some other reason."

<<Cannoli are Sicilian pastry desserts. The singular is cannolo (or in the Sicilian language cannolu), meaning "little tube", with the etymology stemming from the Latin "canna", or reed. Cannoli originated in Sicily and are an essential part of Sicilian cuisine. They are also popular in Italian American cuisine and in the United States are known as a general Italian pastry, while they are specifically Sicilian in origin (in Italy, they're commonly known as "cannoli siciliani", Sicilian cannoli).

Cannoli consist of tube-shaped shells of fried pastry dough, filled with a sweet, creamy filling usually containing ricotta. They range in size from "cannulicchi", no bigger than a finger, to the fist-sized proportions typically found in Piana degli Albanesi, south of Palermo, Sicily. Cannoli were historically prepared as a treat during Carnevale season, possibly as a fertility symbol; one legend assigns their origin to the harem of Caltanissetta. The dessert eventually became a year-round staple throughout what is now Italy. Cannoli are sometimes called cannolis, however this is not the correct term. "Cannoli" is the proper plural, and "cannolo" the singular. >>

NoelC wrote:I'm left to wonder whether an atmospheric pressure of 1% of that of Earth doesn't kind of cut out most of the possibility of "life as we know it" - at the surface at least.

alter-ego wrote:No doubt I'm barking up the wrong tree, but I can't help interpreting those dirty blue-white features as dust-covered ice nodules / layers. I realize the image is a reprojection with a synthetic sky and color-enhanced, but the colors don't seem so far off. I'd sure like to see an explanation about those particular features.

alter-ego wrote:Here is another interesting article (and here).

bystander wrote: http://asterisk.apod.com/viewtopic.php?f=31&t=24723

APOD Robot wrote: Seasonal Dark Streaks on Mars

Explanation: What is causing these dark streaks on Mars? A leading hypothesis is flowing -- but quickly evaporating -- water. The streaks, visible in dark brown near the image center, appear in the Martian spring and summer but fade in the winter months, only to reappear again the next summer. These are not the first markings on Mars that have been interpreted as showing the effects of running water, but they are the first to add the clue of a seasonal dependence. The image is color-enhanced and depicts a slope inside Newton crater in a mid-southern region of Mars.

http://www.archive.org/stream/throughspaceandt031585mbp/throughspaceandt031585mbp_djvu.txt wrote:

THROUGH SPACE & TIME (1934)
BY SIR JAMES JEANS

<<[Astronomers] find no direct evidence of water vapour in the [Martian] atmosphere, although it has often been thought that there is a certain amount of circumstantial evidence that water vapour is present. It is noticed that dark patches appear regularly in the Martian spring, and fade away again in the autumn mainly in the tropical regions and southern hemisphere. It was at first thought that these were real seas of water, but this is now considered improbable. For one thing, they vary too much and too rapidly in colour; one, for instance, was observed to change from blue-green to chocolate-brown and back again within a very few months. They also resemble the supposed seas on the moon in never reflecting the sunlight, as sheets of real water would do. At one time astronomers thought they might be forests, or masses of vegetation. Since then the surface of Mars has been examined in the same way as the surface of the moon, and appears to be of somewhat similar composition possibly volcanic lava or some such substance. Thus the dark patches may be produced by showers of rain wetting a dead dry surface like that of the moon.

Mars has days and seasons very like our own. It takes 24 hours and 37 minutes to turn on its axis, so that its day is slightly longer than ours. And as this axis is tilted at an angle of 25 10', as against the earth's angle of 23 27', we must expect to find the Martian seasons rather more pronounced than ours on earth; there will be a greater difference between summer and winter. On top of this, however, there is a further cause of variation in the climate on Mars.

The earth's path round the sun is very nearly circular not quite, since the earth's distance from the sun is 3 per cent, less in December than in June. We inhabitants of the northern hemi- sphere are closest to the sun at our mid-winter, while people in the southern hemisphere are closest at their mid-summer. Thus the small variations in our distance from the sun go to lessen the difference between summer and winter in the northern hemisphere, but accentuate it in the southern hemisphere. As a consequence, we must go to the South Pole rather than to the North for extremes of climate.

Nevertheless, the earth's distance from the sun does not vary enough to produce any great effect on our climate. It is different with Mars, whose path is nothing like so circular as that of the earth. Our distance from the sun varies by less than 3 million miles, but that of Mars varies by more than 26 million miles. Thus, when Mars approaches the sun, the climate of the whole planet becomes appreciably warmer; as it recedes, the whole planet gets colder. These alternations of general coldness and general warmth are of course superposed on top of the ordinary Martian seasons. The maximum of general warmth, the time when Mars is nearest the sun, occurs shortly before mid-summer in the southern hemisphere, so that on Mars, as on earth, we must go to the southern hemisphere for extremes of climate. Furthermore, the extremes will be far more marked than with us.

Now if we are planning to land our rocket on Mars, we may as well take advantage of what warmth there is even so, we shall soon find there is little enough. Let us then arrange to arrive when Mars is nearest the sun i.e. at the middle of the period of general warmth and to land slightly south of the equator at mid-day. Here we may find a temperature as high as 60 degrees Fahrenheit.>>

Ann wrote:That reminds me of when I was in the United States in 1971 and tried to speak English, and I thought "backside" just meant the "back" of something, like the reverse of a coin...

Ann wrote:
Fascinating, Art. James Jeans knew in 1934 what NASA needs to make a special announcement about in 2011. (Maybe I'm being cynical.) But hey... James Jeans had nothing remotely like today's splendid APOD to back up his knowledge with. He knew anyway, through careful assessment of observations that had been made and conclusions that could be drawn from the 1934 knowledge about Mars.

bystander wrote:

Ann wrote:
That reminds me of when I was in the United States in 1971 and tried to speak English, and I thought "backside" just meant the "back" of something, like the reverse of a coin...

It does, what do you think it means, now?

neufer wrote:I was just reading the following book that was awarded to my father
"for excellence in mathematics" at commencement from his prep school in 1935:
THROUGH SPACE & TIME (1934)
BY SIR JAMES JEANS

NoelC wrote:Well, I guess it's pretty darned clear why we have no flying cars now.