(CNN) — From a sheep ranch in Western Australia comes the oldest slice of Earth we know.
Scientists say they have dated an ancient crystal called a zircon to about 4.4 billion years, making it the earliest confirmed piece of the planets crust. The findings — the first to describe the zircon — were published in the journal Nature Geoscience on Sunday.
This is the oldest and the best dated of all the crystals that have been reported, said John Valley, lead study author and professor in the Department of Geoscience at the University of Wisconsin-Madison.
This crystal is a translucent red, Valley said, but glows blue when bombarded with electrons. At 400 micrometers long, its biggest dimension is just a tad larger than a house dust mite, or about four human hairs.
The crystal was found in an arid region north of Perth, Australia, in a low range of hills called the Jack Hills, in 2001.
Scientists say the crystals chemistry — specifically, the ratio of oxygen isotopes within it — suggests that the temperatures on Earth 4.4 billion years ago would have supported liquid water, and therefore perhaps life. Two isotopes of an element are considered different if they contain different numbers of neutrons.
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What weve learned is that the Earth cooled much more quickly that people had thought, Valley said. The surface formed a crust much more quickly than people thought.
A brief history of Earth
Our planet is thought to be about 4.5 billion years old, but the oldest fossils are about 3.5 billion years old. That doesnt necessarily mean that no life existed before that time, but no direct evidence has been found yet.
The first rocks that have been found deposited by water are about 3.8 billion years old, Valley said.
But very little is known about the first 600 million years or so of the planets history, known as the Hadean Eon because it was thought to be hell-like, Valley said.
The leading theory is that Earth was bombarded by meteors in its early history. It took a big hit from an object the size of Mars about 4.5 billion years ago, leading to the formation of the moon. These impacts vaporized the Earths crust and formed a super-hot magma ocean.
Evidence including this zircon suggests that within the first 100 million to 200 million years of its existence, our planet cooled enough to make crust. Steam from the atmosphere condensed to make oceans.
Once you know that there were oceans, its very reasonable that there would have been life that early — even when it was only 200 million years old, Valley said.
How they did the study
Valley and colleagues reported on a different crystal from early Earth in 2001 from the same Jack Hills area. But there had been an open question regarding that crystal and others about how to determine the age.
The standard method of dating such rocks involves looking at the radioactive decay of uranium atoms to lead. But if the lead has moved within the crystal over time, this could lead to a faulty estimate of age. If lead has migrated away from the area of the rock being tested, that could make the rock appear younger than it is, or older if lead has concentrated itself.
In this new study, researchers used a technique called atom-probe tomography, which allows scientists to image single atoms of lead and determine the isotope ratio.
Scientists found that clumps of lead atoms had formed 1 billion years after the zircon crystallized. These clusters are tiny, about 5 to 10 nanometers in diameter.
All that means that the lead atoms hadnt moved enough to thwart scientists existing methods of determining the crystals age, Valley said. They determined that age to be 4.4 billion years old.
Although incredibly laborious, their analytical technique can be applied to not only additional terrestrial zircons but also to zircons from meteorites and lunar samples, to perhaps tease out a detailed thermal history of magmatism and impacts, Samuel Bowring, professor of geology at Massachusetts Institute of Technology, wrote in an accompanying article in Nature Geoscience.
Meanwhile, on Mars
Earth and Mars formed around the same time in the solar system. Just as scientists are analyzing the chemical composition of rocks on Earth to learn about our planets history, NASAs Curiosity rover is doing the same on Mars.
But one can only do so much via robot. NASA is planning a 2020 rover mission that may be able to collect samples for later delivery to Earth.
There, we may find even more extraordinary gems — red or otherwise.
Rio de Janeiro, Brazil (CNN) — High above the beaches in Rio de Janeiros hillside slums, you can get some of the best views in town. And now, they come from some of the cheapest rooms as well.
With the World Cup less than four months away, residents in many once infamous favelas are opening their doors to tourists, renting beds, rooms or even entire houses, and building youth hostels.
If you want to see the World Cup, see some football matches and experience true Brazilian life you should really check this out, says Michael Blommers, a Dutch backpacker staying at a hostel in the Vidigal shantytown.
Beds at hostels in Copacabana and Ipanema beaches, which usually go for around $40 a night, are expected to cost as much as $400 during the World Cup. Hotels are even more expensive, with many requiring multiple-night stays.
A tourist in Rios Vidigal favela calls to a dog on a street.
But a bunk at Alto Vidigal Hostel will set guests back just $65 — four times the usual price, but still a relative bargain.
Of course, visitors staying in Rios favelas will likely be confronted with more than just a modest room. Garbage in these areas often piles up along the roads, while electricity, water and sewage services are spotty at best. Transportation can be precarious.
The biggest concern, though, is security. Just a few years ago, Rios favelas were controlled by drug lords. Police have since stormed many of them, in a process dubbed pacification, driving out armed gangs in an effort to make it relatively safe for residents and visitors. But theyve had mixed results.
Periodic gun battles continue in many favelas. Just last week, drug traffickers shot at police posts in Rocinha, one of the biggest shantytowns in Rio.
Maria Clara dos Santos says she could hear the recent shootouts from her terrace. She rents rooms in her bright yellow house to foreign tourists and says safety depends on knowing where not to go and following rules.
Dont use drugs, dont bring girls home, keep it a nice environment, she says.
A Los Angeles native, Elliot Rosenberg has launched a website with an eye on the World Cup allowing residents to rent out rooms to foreigners.
With some 600,000 foreign fans expected over the course of the tournament, there could be plenty of demand. But Rosenberg believes that many of those looking for rooms will be attracted by more than just the about $50 price tags on many rooms.
They want more authentic, lively, meaningful experiences, he says. They want to see the real Rio.
And, of course, those great views dont hurt either.
Curitiba stadium retains World Cup status
(CNN) — At least two members of Libyas General National Congress were shot and wounded after protesters stormed its headquarters in Tripoli on Sunday evening, according to congress members.
One of the congressmen, Abdul Rahman Sweihli, was shot in the leg after protesters opened fire on him inside the building.
As his security detail rushed him out, gunmen opened fire on their cars as they were trying to flee, his son Bashir Sweihli told CNN.
No information about the second lawmaker was available.
A GNC member speaking on Libyan TV said lawmakers continued their evening session despite dozens of protesters surrounding the building and pouring gasoline on the walls before they stormed the building.
Other members of the GNC, the countrys interim parliament, were assaulted, and some of the women members harassed, lawmakers said.
Young men ransacked the building, and parts of it were set on fire, according to witnesses.
Videos posted to social media sites showed a chaotic scene, with young men setting cars and furniture outside the building ablaze.
Public anger has been mounting against the GNC, especially after members voted last December to extend their term in office until the end of this year.
For almost a month, thousands of Libyans have taken to the streets across the country in peaceful demonstrations demanding an end to the GNCs term.
In response to the rising tensions, lawmakers announced last month that early elections would be held, but a date has not yet been set.
Earlier in the day, anti-GNC protesters blocked off roads close to the building and set tires on fire after reports spread of an attack Saturday night on anti-GNC protesters. That attack included burning down their tent and reportedly kidnapping some protesters.
More than two years after the overthrow of the Gadhafi regime, Libyans have become increasingly frustrated with the state of their country and the performance of their elected officials.
Separately on Sunday, gunmen shot dead a French national in the eastern city of Benghazi.
Local authorities condemned the killing and said the man was an employee of a private French company that was doing expansion work on the Benghazi Medical Center.
The French Foreign Ministry condemned the killing of the man identified as Patrice Real and said the perpetrators must be pursued and punished.
A Libyan soldier was also killed in Benghazi on Sunday when an improvised explosive device detonated under his car, according to the state news agency LANA.
Four unidentified bodies of young men with gunshots to the head were found in a forest east of Benghazi, LANA reported.
Separately, a fifth unidentified body was discovered in al-Jarutha, west of the city.
Violence levels in the city have spiked over recent weeks with assassinations, kidnappings and bombings becoming near daily occurrences in the city that was the cradle of Libyas revolution.
While no group has claimed responsibility for the rising violence in Benghazi, residents and officials blame the violence on Islamist extremist groups.
Last week security forces found the bodies of seven Egyptian Christians dumped west of the city.
(CNN) — The crowdfunding model, in which entrepreneurs seek online pledges to finance their pet projects, appears to be alive and well.
Kickstarter, the platform that has helped launch the Pebble smartwatch, the Oculus Rift gaming headset and the upcoming Veronica Mars movie, said it surpassed $1 billion in pledges on Monday. Although Kickstarter has been around for almost five years, it said more than half of the money was pledged in the past 12 months.
$1 billion means that people care about new ideas, said the company in a special page announcing the milestone. The money helped bankroll 57,000 creative projects, from films and comic books to tech gadgets and video games.
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Pledges came from 5.7 million people in 224 countries, most commonly the United States ($663 million), the UK ($54 million) and Canada ($45 million).
Thats a far cry from Kickstarters first day — April 28, 2009 — when a grand total of 40 people pledged $1,084 to seven projects.
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The site requires project creators to choose a deadline and a target funding goal, with financial backers typically receiving preferential access to their product. Kickstarter takes 5% of all successfully funded projects. Investors are only charged if the project reaches its stated goal within the alloted time for fundraising — otherwise no money changes hands.
If youre wondering, Wednesday is the day of the week when backers have pledged the most money, while pledges usually drop off on weekends.
Kickstarter is part of a growing number of crowdfunding sites that include Indiegogo, RocketHub and Crowdrise. Last month Kickstarter urged users to change their passwords after revealing it had been hacked.