Astronauts recently experienced an historic vegetable moment when they ate a salad made from lettuce grown on board the International Space Station.

The power source for Earth's magnetic field

Metal 'Snow' May Power Earth's Magnetic Field



Credit: Johan Swanepoel | Shutterstock.com
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The power source for Earth's magnetic field may be magnesium that has been trapped in the core since our planet's violent birth, a new model suggests.

Magnesium is the fourth most common element in the Earth's outer layers, but previously, scientists thought there was almost no magnesium in the core. Iron and magnesium don't easily mix, and researchers thought that the Earth's core was mostly iron.

However, that thinking has changed because of recent theories proposing that the Earth was born from a series of violent collisions with other protoplanets. During the impacts, temperatures and pressures were so intense that iron and metal could combine in an alloy, according to a study published today (Jan. 20) in the journal Nature. The study authors add that smashing together two planetary bodies likely injected magnesium into the core. About 1 percent of the core (by weight) could be magnesium, the new model shows. [Religion and Science: 6 Visions of Earth's Core]





"We think we now understand why the Earth has had a magnetic field for the last 4 billion years, and that the process will keep happening into the foreseeable future," said lead study author Joseph O'Rourke, a graduate student in planetary science at Caltech in Pasadena, California.

O'Rourke and study co-author Dave Stevenson, a Caltech professor, created a model of Earth's formation to investigate magnesium's behavior in the core. As Earth's core has slowly cooled, magnesium-oxide minerals are "snowing" out from the core's iron and nickel alloy, the model indicates. This solid magnesium "snow" is lighter than the liquid metal and floats outward through the liquid-metal outer core, churning it and powering the convection that produces the global magnetic field.

The new model could help solve an important question in planetary science: What has powered the Earth's magnetic field for the past 4 billion years? Many scientists think iron cooling and solidifying in Earth’s core generates the planet's magnetic field (also called the geodynamo). However, these models can't explain how the magnetic field was generated before the solid inner core formed about 1 billion years ago. The new magnesium model provides an alternative energy source.

With the new model, "you don't have to invoke anything crazy in the past to explain the geodynamo," O'Rourke told Live Science.

The new model needs to be verified with experimental tests, the researchers said. There is little evidence indicating how magnesium behaves at the temperatures and pressures produced during planetary collisions.

"The idea is an interesting one," said Rebecca Fischer, a postdoctoral fellow at the Smithsonian Museum of Natural History in Washington, D.C., who was not involved in the study. However, "before we can really, conclusively say how much magnesium goes into the core, we need better experimental data," Fischer told Live Science.

One group is already conducting such experiments. James Badro, a geophysicist at the Institut de Physique du Globe in Paris, has led studies that simulate the early Earth and appear to confirm O'Rourke and Stevenson's modeling.

"There's enough data to convince us that our model of the magnesium process works in general, but sorting out a lot of the details will require more experiments," O'Rourke said.

A magnetic field is important for life because it shields the planet and the atmosphere from the solar wind. Knowing how ancient Earth's magnetic field kicked into gear may help improve estimates of when life first appeared and inform the search for life on other planets.

NASA Measures Winds in Tropical Cyclone Victor

Victor (Southern Pacific Ocean)

NASA Measures Winds in Tropical Cyclone Victor

NASA's RapidScat instrument found the strongest winds in Tropical Cyclone Victor were occurring south of its center on January 20. Imagery from NOAA's GOES-West satellite revealed that Victor still maintained hurricane-strength and an eye.

NOAA's GOES-West satellite captured this image of Tropical Cyclone Victor in the South Pacific on Jan. 20 at 1500 UTC (10 a.m. EST).

Credits: NASA/NOAA GOES Project

As Victor continues moving in a southerly direction a gale warning was posted for the island country of Niue. Tonga is located to the west and the Cook Islands to the east.

RapidScat is an instrument on the International Space Station that measures surface winds over oceans. On Jan. 20 at 2 a.m. EST, RapidScat saw Tropical Cyclone Victor's strongest winds south of the center at 34 meters per second (76 mph/122 kph).

On Jan. 20 at 2 a.m. EST, RapidScat saw Tropical Cyclone Victor's strongest winds (red) south of the center at 34 meters per second (76 mph/122 kph).

Credits: NASA JPL, Doug Tyler

At 0900 UTC (4 a.m. EST), Tropical Cyclone Victor had maximum sustained winds near 65 knots (75 mph/120.4 kph) so it was still maintaining status as a Category 1 hurricane on the Saffir-Simpson Scale. It was centered near 21.6 degrees south latitude and 168.9 degrees west longitude, about 360 nautical miles east of Tonga. Victor was moving to the west-southwest at 4 knots (4.6 mph/7.4 kph).

NOAA's GOES-West satellite captured an image of Tropical Cyclone Victor in the South Pacific on Jan. 20 at 1500 UTC (10 a.m. EST) that showed the storm maintained an eye, and had powerful bands of thunderstorms around the center.

Forecasters at the Joint Typhoon Warning Center expect Victor to weaken steadily over the next few days, before turning to the south and becoming extra-tropical.

Rob Gutro
NASA’s Goddard Space Flight Center

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Jan. 19, 2016 - NASA Sees Wide-Eyed Tropical Cyclone Victor

NASA satellites and instruments have been monitoring Tropical Cyclone Victor, a hurricane in the South Pacific Ocean with a large eye. NASA's Aqua satellite, NASA-NOAA's Suomi NPP satellite and the RapidScat instrument aboard the International Space Station have all gathered data on the storm.

On Jan. 16, 2016 (left) RapidScat measured Victor's strongest winds near 30 meters per second (67 mph/108 kph) in all quadrants except the western side. On Jan. 18 (right) slightly weaker. By Jan. 18 strongest winds had increased to 36 mps/80.5 mph/129.6 kph in all but the northern side.

Credits: NASA JPL, Doug Tyler

The RapidScat instrument that flies aboard the International Space Station measured Tropical Cyclone Victor's wind speed at the surface. Surface wind speed is always lower than speeds at higher altitude.

RapidScat is an important tool for meteorologists, because maximum sustained winds are not always equally distributed in a hurricane or tropical storm. RapidScat sustained wind data shows forecasters the location of the strongest winds in different quadrants of a storm. On Jan. 16 RapidScat measured Victor's strongest winds near 30 meters per second (67 mph/108 kph) in all quadrants except the western side, which was slightly weaker. By Jan. 18, the storm was hurricane-strength and those strongest winds had increased to 36 meters per second (80.5 mph/129.6 kph) and shifted to the western, southern and eastern quadrants of the storm.

On Jan. 18 at 00:45 UTC (Jan. 17 at 9:45 p.m. EST) the MODIS instrument aboard NASA's Aqua satellite saw Tropical Cyclone Victor in the South Pacific Ocean.

Credits: NASA Goddard MODIS Rapid Response

On Jan. 18 at 00:45 UTC (Jan. 17 at 9:45 p.m. EST) the MODIS or Moderate Resolution Imaging Spectroradiometer instrument aboard NASA's Aqua satellite provided a visible light image of Tropical Cyclone Victor. At that time, Victor's eye was almost due east of the Cook Islands.

On Jan. 19 at 01:00 UTC the VIIRS instrument aboard NASA-NOAA's Suomi NPP captured this image of a wide-eyed Tropical Cyclone Victor in the South Pacific Ocean.

Credits: NASA Goddard Rapid Response

By Jan. 19 at 01:00 UTC when NASA-NOAA's Suomi NPP satellite passed over Victor, the eye had moved southeast of the Cook Islands. The VIIRS instrument aboard Suomi NPP captured another visible image of the wide-eyed hurricane and observed that the eye was more open than it was during the time the Aqua satellite passed overhead. The eye was about 35 nautical miles (40 miles/64 km) wide. The Suomi image showed strong bands of thunderstorms wrapping into that ragged eye.

Later in the day at 0900 UTC (4 a.m. EST), Victor's maximum sustained winds were near 80 knots (92 mph/ 148.2 kph). Victor was moving to the southwest at 6 knots (6.9 mph/11.1 kph). It was centered near 20.9 degrees south latitude and 167.3 degrees west longitude, about 410 nautical miles west of Rarotonga, Cook Islands.

Forecasters at the Joint Typhoon Warning Center expect Victor to continue moving in a west-southwesterly direction while slowly weakening over the next couple of days. By. Jan. 22, Victor is forecast to turn to the south and will have weakened to tropical storm status and transition into an extra-tropical storm.

Rob Gutro
NASA's Goddard Space Flight Center

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Prison or Graveyard

Δημοσιεύτηκε στις 17 Ιαν 2016

In Honduras, there are 24 prisons where the prisoners are supposed to be rehabilitated. However, these prisons have been a place for committing the most heinous crimes.

Chile's Indigenous Mapuche In Violent Conflict With The State

The story of the Mapuche people is one of racial division and oppression. Indigenous to southern Chile, the Mapuche were driven from their land by Spanish settlers; they are now fighting a violent battle to reclaim what is theirs.

"They have to give back what they stole. The rights of the Mapuche are not respected", explains Juan Millacheo, a Mapuche community leader. Amidst allegations of violence, police abuse and corruption, Millacheo and his people are battling the Chilean state to recover their rightful homes. "We are people as well", he says. "We are children of God". "Violence is a very good way of doing business for the Mapuche. That's how they get land", counters lawyer Juan Fuentes. The state argues that the Mapuche are using force and intimidation, often against innocent civilians, to get their way. Victims describe having their houses burned and their livestock killed as the Mapuche drive them from their land. "They enter houses, tie down the owners and threaten to burn them down... if that's not terrorism then what is?" As the Mapuche battle the Chilean state for their supposed birthright, the conflict grows increasingly violent with each day. This report explores the origins of this bitter struggle and the innocent victims caught in the crossfire.

'Death to heathen Christians' scrawled on walls of Jerusalem's Dormition Abbey