A meteorite contrail is seen over a village in Russia’s Chelyabinsk region on Friday, Feb. 15, 2013. (AP)

Earth suddenly seems to be dodging celestial objects, although there was a direct hit earlier today when a streaking meteorite exploded above Russia’s Ural Mountains.

Hundreds of people were injured.  The powerful blast damaged the facades of buildings and shattered windows, according to the Russian Interior Ministry,

Now all eyes are on an asteroid that should zip past our planet today at 1924 UTC. However, experts say we are in no danger from asteroid 2012 DA14.

“According to NASA scientists, the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14′s trajectory is in the opposite direction, from south to north.”

This animated set of images depicts asteroid 2012 DA14 as it was seen on 02-14-13, at a distance of 748,000 kilometers. The asteroid is the large bright spot moving near the middle of image. The other dots are stars in the background. A line that appears comes from a satellite that passed through the field of view.(Image credit: LCOGT/E. Gomez/Faulkes South/Remanzacco Observatory)

The asteroid is expected to fly past us at a speed of about 7.8 kilometers per second, coming within 27,000 kilometers of Earth. That’s close enough so that it will pass inside the ring of geosynchronous weather and communications satellites that circle our planet at about 36,000 kilometers above Earth.

The Barringer (or Meteor) Crater in Arizona measures 180 meters deep and 1,200 meters wide. Scientists estimate that a small asteroid, about the same size as the passing 2012 DA14, created the hole some 25,000 years ago. (Photo: Kevin Walsh @ Creative Commons via Flickr)

NASA, which has been studying the asteroid’s path, says there’s no chance the asteroid might collide with Earth. The flyby will, however, provide a unique opportunity for researchers to study a near-Earth object up close.

The 2012 DA14 asteroid is about 45 meters across, less than the width of a soccer field, weighs about 130,000 metric tons, and is most likely made of stone, rather than metal or ice.

Although the passing asteroid is relatively small in size, it could pack a mighty punch if it did swerve out of its projected path and hit the Earth.

Jack Rozdilsky an emergency management expert at Western Illinois University has considered the possibility of a hit.

“If the 150-foot asteroid passing Earth on Friday were on a collision course with the planet, it would impact the surface with an explosive force of 2.4 megatons of TNT,” Rozdilsky said.

While such a hit would not be planet destroying, it could wipe out a large metropolitan area in a one single blow.

“While popular disaster films such as ‘Armageddon’ have depicted fictionalized accounts of asteroids threatening Earth, asteroid impacts on Earth are not necessarily far-fetched,” Rozdilsky said. “In 1908, a comet impacted Tunguska, a forest in a remote area of northern Russia, with the resultant explosion devastating a large unpopulated area.”

A NASA animation show the trajectory of asteroid 2012 DA14 as it travels within the Earth-moon system on Feb. 15, 2013

Drawing of the path of near-Earth asteroid 2012ge DA14 when it passes close to Earth on Feb. 15, 2013. (NASA)

Earth is about to have a close encounter with an asteroid, the nearest an object of its size has ever come to our planet.

The fly-by is expected to occur at around 1924 UTC on Feb. 15, according to scientists at NASA’s Jet Propulsion Laboratory.

The US space agency says there’s no chance the asteroid will collide with Earth.

“This is a record-setting close approach,” says Don Yeomans of NASA’s Near Earth Object Program at JPL. “Since regular sky surveys began in the 1990s, we’ve never seen an object this big get so close to Earth.”

Scientists expect the asteroid to pass us at a distance of about 27,700 km from the surface of the Earth. That’s close enough for it to pass inside the ring of a number of geosynchronous weather and communications satellites currently orbiting the Earth at about 36,000 km from Earth’s surface above the equator.

However, the asteroid should fly well above most of the satellites and spacecraft circling the planet, including the International Space Station (ISS).

To get an idea of just how close the 2012 DA14 asteroid will get to us, consider that it will come nearer to us than the moon, about 1/13th of the distance to the Moon, which is 384,400 km from Earth.

It’s expected to whiz by our planet quite fast, at a speed of about 7.8 kilometers per second in a south-to-north direction. This will be the closest an asteroid has come to Earth in at least 30 years and will give researchers a unique opportunity  to study it.

The 2012 DA14 is quite small, weighing about 130,000 metric tons and measuring about 45 meters across, less than the width of a soccer field. Astronomers believe it is made of stone, rather than metal or ice.

The asteroid was discovered by astronomers at the OAM Observatory in La Sagra, Spain less than a year ago, on Feb. 23, 2012, which is why “2012″ is part of its name.

NASA video feature of asteroid fly-by

A few other asteroids have flown even closer to Earth, but they were much smaller than the one expected to zoom by this month.  Scientists say objects of this size fly this close to the Earth about once every 40 years; an actual collision with Earth happens about every 1,200 years.

The 2012 DA14 asteroid is so tiny, it’s expected to look like a small point of light, even to those using the biggest optical telescopes. Difficult to see with the naked eye, it will be easily visible with a good set of binoculars or a small telescope.

Astronomers say the best place to see the asteroid will be in Indonesia, but people in Eastern Europe, Asia and Australia should also be able to get a glimpse.

The public can watch the event through live feeds from telescopes in La Sagra and Tenerife, Spain.

NASA astronomers at the Goldstone Deep Space Communications Complex (GDSCC) in California’s Mojave Desert will use radar imaging to determine the orbit of the asteroid, allowing them to better predict future encounters. The imaging data will also be used to create a 3D map showing the asteroid from all sides and should reveal more about the asteroid’s physical characteristics, such as its size and spin.

Artist’s rendition of astronauts on Mars. (NASA)

Traveling into deep space could accelerate the onset of Alzheimer’s disease, an incurable form of dementia, according to a new report.

The NASA-funded study assessed how cosmic radiation would impact the astronauts throughout their trip in deep space. The effect of cosmic radiation on the human body has been a  concern for the US space agency as it plans manned missions into deep space, such as one to a distant asteroid in 2021, and another to Mars in 2035.

Earth’s magnetic field usually keeps us, and those in low Earth orbit, safe from the perils of cosmic radiation. However, beyond Earth’s protective magnetic fields, space travelers are exposed to a constant barrage of radiation.

With adequate warning, such as in the case of solar flares, steps can be taken to protect astronauts from dangerous forms of radiation. However, other forms of cosmic radiation, which occur without warning, cannot be blocked as effectively.

“Galactic cosmic radiation poses a significant threat to future astronauts,” said M. Kerry O’Banion,  a professor in the University of Rochester Medical Center (URMC) and senior author of the study. “The possibility that radiation exposure in space may give rise to health problems such as cancer has long been recognized. However, this study shows for the first time that exposure to radiation levels equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer’s disease.”

Artist’s illustration of the shape and function of the Earth’s magnetic field that protects us from harmful cosmic radiation (NASA)

In the past,  scientists studied the impact of cosmic radiation on a living being’s cardiovascular and musculoskeletal systems, as well as potential risks of contracting various forms of cancer.But the new study,  published in  PLOS ONE, examined the possible effects of space radiation on neurodegeneration, a gradual loss of brain structure or function.

For this study, researchers wanted to find out what role, if any, cosmic radiation plays in accelerating the biological and cognitive indicators of Alzheimer’s disease, especially in those  predisposed to developing the illness.

They specifically wanted to learn more about the impact of radiation from high-mass, high-charged (HZE) particles, which come in many forms and travel through space with the force of exploding stars.

Instead of examining hydrogen protons, which are produced by solar flares, the researchers decided to study iron particles. They say HZE particles, such as iron, when combined with their high rate of speed, are able to go through solid objects, like a spacecraft’s walls and protective shielding.

“Because iron particles pack a bigger wallop, it is extremely difficult, from an engineering perspective, to effectively shield against them,” said O’Banion. “One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.”

Brain affected by Alzheimer’s Disease (left) vs normal brain (right) – (US Dept of Veterans Affairs)

The researchers exposed mice to various doses of radiation, including levels that would be similar to what astronauts would experience during deep space voyages.To evaluate the cognitive and biological impact of the radiation exposure, the mice were then put through a series of experiments in which they had to recall objects or specific locations. Researchers observed that the radiation- exposed mice were much more likely to fail these tests, suggesting neurological impairment, earlier than the symptoms would typically appear.

Along with symptoms of neurological damage, the researchers found that the mice’s brains also showed signs of vascular changes and had a greater than usual buildup of beta amyloid, the protein “plaque” that gathers in the brain and is one of the characteristics of Alzheimer’s Disease.

“These findings clearly suggest that exposure to radiation in space has the potential to accelerate the development of Alzheimer’s disease,” said O’Banion. “This is yet another factor that NASA, which is clearly concerned about the health risks to its astronauts, will need to take into account as it plans future missions.”

Fragments of the Sutter’s Mill meteorite fall collected by astronomer Dr. Peter Jennisken. (NASA)

Researchers have struck scientific gold at Sutter’s Mill, site of the famed California Gold Rush where the precious metal was first discovered in 1848.

In April of this year, the scientists recovered a rare meteorite which contains clues to the early history of the solar system.

Using Doppler radar, the same technology used by weather forecasters, the scientists detected a shower of meteors raining down over the communities of Coloma and Lotus, just after the asteroid broke up in the atmosphere.

That allowed scientists to, for the first time,  quickly find, recover and study a primitive meteorite that had little exposure to the elements.

It’s the most pristine look at the surface of ancient asteroids scientists have been able to study so far. Because of the rapid recovery of materials, scientists were able to detect compounds that quickly disappear once a meteorite hits Earth.

Reporting in Science, the researchers say their rare find was classified as a Carbonaceous-Mighei or CM-type carbonaceous chondrite meteorite, which is known to contain water and complex organic compounds, such as amino acids, molecules that help form life.

But, according to NASA’s Danny Glavin, he and the other scientists weren’t able to detect many of the amino acids in their find because it appeared the samples had been heated in space before arriving on Earth.

“The small three meter-sized asteroid that impacted over California’s Sierra Nevada came in at twice the speed of typical meteorite falls,” said lead author Peter Jenniskens, of the SETI Institute and NASA’s Ames Research Center, both located in California. “Clocked at 64,000 miles per hour, it was the biggest impact over land since the impact of the four meter-sized asteroid 2008 TC3, four years ago over Sudan.”

The scientists also say that, for the first time, they were able to identify the region of space where these types of meteorites come from.

After studying photographs and video of the asteroid, Jenniskens figured that it came in on an unusually low-angled orbit, more like a comet‘s orbit, passing closer to the sun than what has been learned from past recorded meteorite falls.

Scientists found the asteroid, as it was in orbit, was influenced by the gravity of both the Sun and Jupiter at times.

“It circled the sun three times during a single orbit of Jupiter, in resonance with that planet,” Jenniskens said.

A meteor flashes across the sky during the peak of the November 2009 Leonid Meteor Shower. (Photo: Ed Sweeney via Wikimedia Commons)

The asteroid that spawned the meteorite was estimated to be around 45359 kg.  Of that, less than 1kg was actually recovered on the ground in the form of 77 tiny meteorites. The biggest of those meteorites was 205 grams.

While the scientists didn’t find much actual gold in the Sutter’s Mill meteorite, about 150 parts per billion, it was still “scientific gold,” according to co-author and cosmochemist Qing-zhu Yin of the University of California at Davis.

“With 78 other elements measured, Sutter’s Mill provides one of the most complete records of elemental compositions documented for such primitive meteorites,” he said.