Libro de Visitas

Johnnieillus

29 Apr 2025 - 09:19 pm

Curiosity rover makes ‘arguably the most exciting organic detection to date on Mars’
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The NASA Curiosity rover has detected the largest organic molecules found to date on Mars, opening a window into the red planet’s past. The newly detected compounds suggest complex organic chemistry may have occurred in the planet’s past — the kind necessary for the origin of life, according to new research.

The organic compounds, which include decane, undecane and dodecane, came to light after the rover analyzed a pulverized 3.7 billion-year-old rock sample using its onboard mini lab called SAM, short for Sample Analysis at Mars.

Scientists believe the long chains of molecules could be fragments of fatty acids, which are organic molecules that are chemical building blocks of life on Earth and help form cell membranes. But such compounds can also be formed without the presence of life, created when water interacts with minerals in hydrothermal vents.

The molecules cannot currently be confirmed as evidence of past life on the red planet, but they add to the growing list of compounds that robotic explorers have discovered on Mars in recent years. A study detailing the findings was published Monday in the journal Proceedings of the National Academy of Sciences.
The detection of the fragile molecules also encourages astrobiologists that if any biosignatures, or past signs of life, ever existed on Mars, they are likely still detectable despite the harsh solar radiation that has bombarded the planet for tens of millions of years.

“Ancient life, if it happened on Mars, it would have released some complex and fragile molecules,” said lead study author Dr. Caroline Freissinet, research scientist at the French National Centre for Scientific Research in the Laboratory for Atmospheres, Observations, and Space in Guyancourt, France. “And because now we know that Mars can preserve these complex and fragile molecules, it means that we could detect ancient life on Mars.”

Leonardrox

29 Apr 2025 - 08:47 pm

Everyone is talking about Greenland. Here’s what it’s like to visit
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A few months ago, Greenland was quietly getting on with winter, as the territory slid deeper into the darkness that envelops the world’s northerly reaches at this time of year.

But President Donald Trump’s musings about America taking over this island of 56,000 largely Inuit people, halfway between New York and Moscow, has seen Greenland shaken from its frozen Arctic anonymity.

Denmark, for whom Greenland is an autonomous crown dependency, has protested it’s not for sale. Officials in Greenland, meanwhile, have sought to assert the territory’s right to independence.

The conversation continues to intensify. A contentious March 28 visit to a US military installation by Usha Vance, the second lady, accompanied by her husband, Vice President JD Vance, was the latest in a series of events to focus attention on Trump’s ambitions for Greenland.

The visit was originally planned as a cultural exchange, but was shortened following complaints from Greenland Prime Minister Mute B. Egede.

Had the Vances prolonged their scheduled brief visit, they would’ve discovered a ruggedly pristine wildernesses steeped in rich Indigenous culture.

An inhospitable icecap several miles deep covers 80% of Greenland, forcing the Inuit to dwell along the shorelines in brightly painted communities. Here, they spend brutally cold winters hunting seals on ice under the northern lights in near perpetual darkness. Although these days, they can also rely on community stores.

The problem for travelers over the years has been getting to Greenland via time-consuming indirect flights. That’s changing. Late in 2024, the capital Nuuk opened a long-delayed international airport. From June 2025, United Airlines will be operating a twice-weekly direct service from Newark to Nuuk.

Two further international airports are due to open by 2026 — Qaqortoq in South Greenland and more significantly in Ilulissat, the island’s only real tourism hotspot.

Vincentjy

29 Apr 2025 - 08:04 pm

Have you ever stumbled upon a QR code in one of these visitor books that led to an unexpected and sinister hidden message? Or perhaps a coded map to the lair of the infamous EliT WilD KilleRS?

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Stephenirolf

29 Apr 2025 - 07:14 pm

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Rogerdierb

29 Apr 2025 - 06:09 pm

Siham Haleem, a private tour guide for 15 years, says that Doha now has many world-class, modern museums — the National Museum of Qatar being a firm personal favorite. And yet he says that visiting Sheikh Faisal’s museum should still be on everybody’s to-do list.
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“For those eager to learn about Qatar’s — and the region’s — heritage and beyond, the museum is an ideal destination,” he says. “Personally, I’m captivated by the car collection, the fossils, and especially the Syrian house, painstakingly transported and reassembled piece by piece.”

Stephanie Y. Martinez, a Mexican-American student mobility manager at Texas A&M University in Qatar likes the museum so much she includes it on all of her itineraries for students visiting from the main campus in Texas.

“The guided tours are very detailed, and the collections found at the museum have great variety and so many stories to unfold,” she says. “Truly, the museum has something to pique everyone’s interest. My favorites are the cars and the furniture exhibits showcasing wood and mother-of-pearl details. Definitely one of my favorite museums in Qatar, every time I visit I learn something new.”

Raynor Abreu, from India, also had praise for the unusual and immense collection.

“Each item has its own story, making the visit even more interesting,” he says. “It’s also impressive to know that Sheikh Faisal started collecting these unique pieces when he was very young. Knowing this makes the museum even more special, as it reflects his lifelong passion for history and culture.”

It takes time and dedication to truly examine the many collections within the museum — especially since most of them are simply on display without explanation.

Eclectic it may be, but it’s hard to fault the determination of Sheikh Faisal, who has brought together items that tell the story of Qatar and the Middle East.

Sarah Bayley, from the UK, says she visited the museum recently with her family, including 16 and 19-year-old teenagers, and was won over by its sheer eccentricity.

“Amazing. Loved it. It is a crazy place.”

Bobbysyday

29 Apr 2025 - 03:36 pm

A federal judge on Tuesday afternoon temporarily blocked part of the Trump administration’s plans to freeze all federal aid, a policy that unleashed confusion and worry from charities and educators even as the White House said it was not as sweeping an order as it appeared.
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The short-term pause issued by US District Judge Loren L. AliKhan prevents the administration from carrying through with its plans to freeze funding for “open awards” already granted by the federal government through at least 5 p.m. ET Monday, February 3.
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The judge’s administrative stay is “a way of preserving the status quo” while she considers the challenge brought by a group of non-profits to the White House plans, AliKhan said.
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“The government doesn’t know the full scope of the programs that are going to be subject to the pause,” AliKhan said after pressing an attorney for the Justice Department on what programs the freeze would apply to. AliKhan is expected to consider a longer-term pause on the policy early next week.
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The White House budget office had ordered the pause on federal grants and loans, according to an internal memorandum sent Monday.

Federal agencies “must temporarily pause all activities related to obligation or disbursement of all Federal financial assistance,” White House Office of Management and Budget acting director Matthew Vaeth said in the memorandum, a copy of which was obtained by CNN, citing administration priorities listed in past executive orders.
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Peterswoft

29 Apr 2025 - 03:14 pm

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Davidmub

29 Apr 2025 - 03:09 pm

Trailer trucks queue to cross into the United States at the Otay Mesa Port of Entry, in Tijuana, Mexico, November 27, 2024. Jorge Duenes/Reuters
New York
CNN
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Since President Donald Trump won the election in November, businesses across the globe have been bracing for higher tariffs — a key Day One promise the president made.

But over a week into his presidency, Trump has yet to enact any new tariffs.
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That could change, come 11:59 p.m. ET on Saturday — the deadline Trump set for when he says he will slap 25% tariffs on all Mexican and Canadian goods and a 10% tariff on all Chinese goods.

The tariffs, he said, will be imposed as a way of punishing the three nations, which Trump claims are responsible for helping people enter the country illegally and supplying fentanyl consumed in the US.

Speaking to reporters from the Oval Office on Thursday, Trump said he meant business, especially with his tariff threats on Mexico and Canada. White House Press Secretary Karoline Leavitt also confirmed on Friday that Trump will levy the 10% tariff on China on Saturday.
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Should these threats be believed? Yes and no, said Trump’s former Commerce Secretary Wilbur Ross.
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The threat of blanket tariffs is likely being overstated, Ross said in an interview with CNN. “There probably will be exclusions, because there are some goods that just are not made here, will not be made here, and therefore, there’s no particular point putting tariffs on.”

Ross, who was one of a handful of initial cabinet members in Trump’s first administration who kept their position for the entire four-year term, said he advocated for such exclusions when he advised Trump on tariff policies.



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Davidrat

29 Apr 2025 - 01:20 pm

While the Cumberland sample may contain longer chains of fatty acids, SAM is not designed to detect them. But SAM’s ability to spot these larger molecules suggests it could detect similar chemical signatures of past life on Mars if they’re present, Williams said.
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“Curiosity is not a life detection mission,” Freissinet said. “Curiosity is a habitability detection mission to know if all the conditions were right … for life to evolve. Having these results, it’s really at the edge of the capabilities of Curiosity, and it’s even maybe better than what we had expected from this mission.”

Before sending missions to Mars, scientists didn’t think organic molecules would be found on the red planet because of the intensity of radiation Mars has long endured, Glavin said.
Curiosity won’t return to Yellowknife Bay during its mission, but there are still pristine pieces of the Cumberland sample aboard. Next, the team wants to design a new experiment to see what it can detect. If the team can identify similar long-chain molecules, it would mark another step forward that might help researchers determine their origins, Freissinet said.

“That’s the most precious sample we have on board … waiting for us to run the perfect experiment on it,” she said. “It holds secrets, and we need to decipher the secrets.”

Briony Horgan, coinvestigator on the Perseverance rover mission and professor of planetary science at Purdue University in West Lafayette, Indiana, called the detection “a big win for the whole team.” Horgan was not involved the study.
“This detection really confirms our hopes that sediments laid down in ancient watery environments on Mars could preserve a treasure trove of organic molecules that can tell us about everything from prebiotic processes and pathways for the origin of life, to potential biosignatures from ancient organisms,” Horgan said.

Dr. Ben K.D. Pearce, assistant professor in Purdue’s department of Earth, atmospheric, and planetary sciences and leader of the Laboratory for Origins and Astrobiology Research, called the findings “arguably the most exciting organic detection to date on Mars.” Pearce did not participate in the research.

Chesteresory

29 Apr 2025 - 01:08 pm

Curiosity has maintained pristine pieces of the Cumberland sample in a “doggy bag” so that the team could have the rover revisit it later, even miles away from the site where it was collected. The team developed and tested innovative methods in its lab on Earth before sending messages to the rover to try experiments on the sample.
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In a quest to see whether amino acids, the building blocks of proteins, existed in the sample, the team instructed the rover to heat up the sample twice within SAM’s oven. When it measured the mass of the molecules released during heating, there weren’t any amino acids, but they found something entirely unexpected.

An intriguing detection
The team was surprised to detect small amounts of decane, undecane and dodecane, so it had to conduct a reverse experiment on Earth to determine whether these organic compounds were the remnants of the fatty acids undecanoic acid, dodecanoic acid and tridecanoic acid, respectively.

The scientists mixed undecanoic acid into a clay similar to what exists on Mars and heated it up in a way that mimicked conditions within SAM’s oven. The undecanoic acid released decane, just like what Curiosity detected.

Each fatty acid remnant detected by Curiosity was made with a long chain of 11 to 13 carbon atoms. Previous molecules detected on Mars were smaller, meaning their atomic weight was less than the molecules found in the new study, and simpler.
“It’s notable that non-biological processes typically make shorter fatty acids, with less than 12 carbons,” said study coauthor Dr. Amy Williams, associate professor of geology at the University of Florida and assistant director of the Astraeus Space Institute, in an email. “Larger and more complex molecules are likely what are required for an origin of life, if it ever occurred on Mars.”