A view of the excavations at Helike. Drekis, Wikimedia CommonsExcerpt from popular-archaeology.com A team of scholars and students will return to explore and investigate the site now thought to be the remains of the lost city of Helike, the lege...
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A false-color mosaic from space shows the northern seas beneath the haze of Titan. Photograph by NASA/JPL-Caltech/University of Arizona/University of Idaho |
news.nationalgeographic.com
TUCSON, Arizona—Two new "magic islands" have joined one reported last year on Saturn's giant moon Titan, Cassini spacecraft observations showed on Monday. The features add to a puzzling vanishing act playing out on the frozen world's seas.
Since Cassini first arrived at Saturn in 2004, its photos of Titan have revealed numerous seas, lakes, and rivers on the giant moon's frozen surface. This summer, images showed a mysterious feature in one sea—the first "magic island"—that appeared glinting on a lake's surface and then quickly vanished.
The find raised speculation that scientists had captured views of waves splashing within the otherwise mirror-smooth liquid methane seas on the moon. Or else it was a fluke.
Now, an August 21 flyby has turned up two more strange reflecting features, magic islands that weren't there in earlier flybys. "They just popped up," says Cornell's Alexander Hayes, who presented the latest survey of Titan's seas at a briefing at the American Astronomical Society's Division for Planetary Sciences meeting.
"They could be waves, or they could be something more solid," says MIT's Jason Soderblom, a member of the Cassini team reporting the observations. "We definitely know now they are something reflecting from the surface."
Since Titan is the only body besides Earth that has rain-carved geography to study, the possibility of a lake with waves intrigued scientists enough to keep them looking.
"After ten years there, Titan still can surprise us," Hayes says. "Titan has dunes, lakes, seas, even rivers. All this makes Titan an explorer's utopia."
An August 21 flyby passing some 599 miles (964 kilometers) above Titan allowed Cassini to investigate the depth of Kraken Mare, the largest sea on the frozen moon. Radar observations from the spacecraft covered a 120-mile (200-kilometer) shore-to-shore strip of the methane sea.
That flyby revealed that Kraken Mare reaches more than 656 feet (200 meters) deep.
A Cassini flyby of Titan viewed a narrow stretch of the moon's Kraken Mare sea.
Photograph by NASA/JPL-Caltech/ASI/Cornell
Depth Charge
Though Earth and Titan are the only known worlds in the solar system with seas and lakes, the ones on Titan are quite different from Earth's. Surface temperatures on the moon are around -290°F (-179°C), and its lakes are filled with liquid methane, ethane, and other liquefied natural gases.
With spring returning to the northern hemisphere of Titan, where Kraken Mare resides, the scientists suspect they will soon see more mysteries disturbing the once placid surface of the seas of Titan.
"We are likely to see more islands showing up," Hayes says. "These lakes and seas are dynamic places."
Excerpt from
time.com
A new analysis of Mars One's plans to colonize the Red Planet finds that the explorers would begin dying within 68 days of touching down
Hear that? That’s the sound of 200,000 reservations being reconsidered. Two hundred thousand is the announced number of intrepid folks who signed up last year for the chance to be among the first Earthlings to colonize Mars, with flights beginning as early as 2024. The catch: the trips will be one way, as in no return ticket, as in farewell friends, family, charbroiled steaks and vodka martinis, to say nothing of such everyday luxuries as modern hospitals and, you know, breathable air.
But the settlers in Jamestown weren’t exactly volunteering for a weekend in Aspen either, and in both cases, the compensations—being the first people on a distant shore—seemed attractive enough. Now, however, the Mars plan seems to have run into a teensy snag. According to a new analysis by a team of grad students at MIT, the new arrivals would begin dying within just 68 days of touching down.
So what could go wrong? That’s what the four MIT students set out to find out, and the short answer is: a lot.
The biggest problem, the students discovered, concerns that business of breathable air. One of the things that’s always made Earth such a niftily habitable place to live is that what animals exhale, plants inhale, and vice versa. Since the Martian astronauts and their crops would be living and respiring in the same enclosed habitats, a perfect closed loop should result in which we provide them all the carbon dioxide they need and they return the favor with oxygen.
Only it doesn’t, the MIT students found. The problem begins with the lettuce and the wheat, both of which are considered essential crops. As lettuce matures, peaking about 30 days after planting, it pushes the 02 level past what’s known as .3 molar fractions, which, whatever it means, doesn’t sound terribly dangerous — except it’s also the point at which the threat of fire rises to unacceptable levels. That risk begins to tail off as the crop is harvested and eaten, but it explodes upward again, far past the .3 level, at 68 days when the far gassier wheat matures.
A simple answer would be simply to vent a little of the excess O2 out, which actually could work, except the venting apparatus is not able to distinguish one gas from another. That means that nitrogen—which would, as on Earth, make up the majority of the astronauts’ atmosphere—would be lost too. That, in turn, would lower the internal pressure to unsurvivable levels—and that’s what gets your 68-day doomsday clock ticking.
There is some question too about whether the hardware that Mars One is counting on would even be ready for prime time. The mission planners make much of the fact that a lot of what they’re planning to use on Mars has already been proven aboard the International Space Station (ISS), which is true enough. But that hardware is built to operate in microgravity—effectively zero g—while Mars’s gravity is nearly 40% of Earth’s. So a mechanical component that would weigh 10 lbs. on Earth can be designed with little concern about certain kinds of wear since it would weigh 0 lbs. in orbit. But on Mars it would be 4 lbs., and that can make all the difference.
“The introduction of a partial gravity environment,” the grad students write, “will inevitably lead to different [environmental] technologies.”
For that and other reasons, technical breakdowns are a certainty. The need for replacement parts is factored into Mars One’s plans, but probably not in the way that they should be. According to the MIT team, over the course of 130 months, spare parts alone would gobble up 62% of the payload space on resupply missions, making it harder to get such essentials as seeds, clothes and medicine—to say nothing of other crew members—launched on schedule.
Then too, there is the question of habitat crowding. It’s easy to keep people alive if you feed them, say, a single calorie-dense food product every day. But energy bars forever means quickly losing your marbles, which is why Mars One plans for a variety of crops—just not a big enough variety. “Given that the crop selection will significantly influence the wellbeing of the crew for the entirety of their lives after reaching Mars,” the authors write, “we opt for crop variety over minimizing growth area.”
Then there is the question of cost—there’s not a space program in history whose initial price tag wasn’t badly lowballed—to say nothing of maintaining that biennial launch schedule, to say nothing of the cabin fever that could soon enough set the settlers at one another’s throats. Jamestown may not have been a picnic, but when things got to be too much you could always go for a walk by the creek.
No creeks here, nor much of anything else either. Human beings may indeed colonize Mars one day, and it’s a very worthy goal. But as with any other kind of travel, the best part of going is often coming home.
Valerie Tarico, AlterNetReligious labels help shore up identity. So what are some of the things non-believers can call themselves?Catholic, born-again, Reformed, Jew, Muslim, Shiite, Sunni, Hindu, Sikh, Buddhist…religions give people labels. The downside can be tribalism, an assumption that insiders are better than outsiders, that they merit more compassion, integrity and generosity or even that violence toward “infidels” is acceptable. But the upside is that religious o [...]
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