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Sun, 07 Feb 2016
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Asteroid Crash May Have Demagnified Mars

Scientists don't know what happened on Mars that caused its magnetic field to collapse. They suspect the planet's liquid metallic core cooled, ending convective currents that spread magnetic field lines through the planet's rock and soil and out into space.

Missing Magnetic Field

But that may just be part of the story.

A team of researchers led by Jafar Arkani-Hamed of the University of Toronto in Canada believe a large asteroid circling the planet set up a gravitational tug-of-war that got Mars' core churning. Eventually, the asteroid lost its grip and crashed into its parent planet. Mars paid a dear price as well. Without the tidal forces, the planet's core lost its momentum, killing off the magnetic field.

What remain are patches of strong magnetic imprints in the oldest parts of Mars' crust. Because the fresher surface features are magnetic-free, scientists believe Mars lost its shield about four billion years ago.


10 Greatest Major-Impact Craters on Earth (photo)


Imagine staring into the sky and seeing a tiny yellow dot, gradually getting closer. That dot doubles in size every second, until it slowly darkens the sky. You realize that this dot is actually the size of New York City and is screeching through the atmosphere faster than the speed of sound, coming right for you. This massive object will cause tsunamis, earthquakes and obliterate natural daylight for years...oh... and it will kill you. Similar asteroid impacts have and will happen on numerous occasions in our earth's history. Today we'll show you the biggest impact craters by diameter.

Cow Skull

Scientists find complete baby dinosaur fossil

Japanese and Mongolian scientists have successfully recovered the complete skeleton of a 70-million-year-old young dinosaur, a nature museum announced Thursday.

The scientists uncovered a Tarbosaurus - related to the giant carnivorous Tyrannosaurus - from a chunk of sandstone they dug up in August, 2006 in the Gobi Desert in Mongolia, said Takuji Yokoyama, a spokesman for the Hayashibara Museum of Natural Sciences, a co-organizer of the joint research project.

"We were so lucky to have found remains that turned out to be a complete set of all the important parts," he said.


Stellar nursery found near Milky Way's violent heart

The neighborhood around a black hole seems like no place to raise a star. Violent gravitational forces can rip gas clouds apart, making it hard for stars to condense. But astronomers have spotted evidence of very young stars in a ring of gas close to the heart of the Milky Way, where a massive black hole is thought to reside.


These protostars, 6 to 20 light years from the galaxy's centre, are shrouded by so much gas and dust that they can't be seen with telescopes. Instead, Farhad Yusef-Zadeh of Northwestern University in Evanston, Illinois, and colleagues found them through their radio signals.


Is the eclipse in the Odyssey actually an historical account?


A solar eclipse that occurred more than 3000 years ago may be mentioned in the Odyssey, an ancient poem based on Greek mythology, a new study suggests.

The poem, attributed to the poet Homer, describes the 10-year journey that its hero, Odysseus, took to return home to Ithaca, a Greek island in the Ionian Sea, after the end of the Trojan War. The war was waged over the beautiful Helen of Troy, a daughter of the god Zeus.

Days before Odysseus returned home to kill the 108 suitors courting his wife, a prophet predicted the men's doom. "The Sun is blotted out of heaven, and a blighting gloom is over all the land," the sage said.

In fact, a total solar eclipse - in which the disc of the Sun was blocked by the Moon - is calculated to have taken place on 16 April 1178 BCE over the Ionian Islands.

That is around the estimated end of the Trojan War, which despite its appearance in mythology may represent an actual conflict or series of conflicts in the city of Troy in the 12th century BCE.


Total Solar Eclipse to Pass Over China and Siberia

©Fred Espenak/NASA/Goddard Space Flight Center
On 1 August, a total solar eclipse will be visible from Canada to China. The path is shown in blue

Researchers and sky watchers are en route to remote regions of the Earth to catch a glimpse of a total solar eclipse.

On 1 August, the Moon will pass in front of the Sun, casting a shadow across the Earth. Much of the northern hemisphere will see a partial eclipse, but the total eclipse will only be visible in a narrow band as the shadow tracks from Canada to China.

Totality is expected to be relatively short, lasting at most about two and a half minutes. In contrast, a total eclipse in 2009 will last more than six and a half minutes in some places.

Despite the short duration of this year's event, expeditions are underway to Russia and China to see it. Several aircraft will aim to observe the eclipse from above the clouds, and an icebreaker will bring watchers to the Svalbard Islands in the Arctic.


Astronomers See Disks Surrounding Black Holes, Strengthened Evidence For Current Explanation Of Quasars

For the first time, a team of international researchers has found a way to view the accretion disks surrounding black holes and verify that their true electromagnetic spectra match what astronomers have long predicted they would be.

©Makoto Kishimoto, with cloud image by Schartmann
A polarizing filter attached to a telescope suppresses the light emitted by dust particles and ionized gas clouds around the quasar so its true electromagnetic spectrum can be revealed.

A black hole and its bright accretion disk have been thought to form a quasar, the powerful light source at the center of some distant galaxies. Using a polarizing filter, the research team, which included Robert Antonucci and Omer Blaes, professors of physics at the University of California, Santa Barbara, isolated the light emitted by the accretion disk from that produced by other matter in the vicinity of the black hole.

"This work has greatly strengthened the evidence for the accepted explanation of quasars," said Antonucci.


Scientists: Humans and machines will merge in future

Robot Hand
©Getty Images
Some experts say humans will merge with machines before the end of this century.

LONDON, England -- A group of experts from around the world will Thursday hold a first of its kind conference on global catastrophic risks.
Dr. Nick Bostrom says superintelligent beings could pose an existential risk to human life.

Comment: This, of course, assumes that human civilization survives long enough to disseminate such technologies publicly.


Trouble comes in threes: New contamination incident at French nuclear site

Around 100 staff at a nuclear power plant in southern France were contaminated with a low dose of radiation on Wednesday, power firm EDF said, the latest incident there after a case of uranium spillage two weeks ago.

The large Tricastin enrichment facility includes four nuclear reactors that provide over 3000 MWe power for the plant.


Planting Ideology

How Soviet leaders resisted the study of genetics and destroyed a great scientist.

Comment: Did you catch that last remark? Although the Soviet Union destroyed a great scientist, they saved his life's work. Strange that. It reminds one of article like this and this.