Harmful effects of cosmic rays on brain researched

Future manned deep space missions would expose astronauts to levels of radiation that can accelerate the onset of Alzheimer's disease (Image: NASA, JAXA)

Unlike the later on discarded "space madness" problem , studies now have shown that the cosmic rays to which astronauts will be exposed during future manned missions could cause cognitive problems and  even hasten the onset of Alzheimer's Disease. This is an addition to the already large list of possible effects of cosmic rays, along with cancer risk, impact on cardiovascular and skeletomuscular system, which have been found in the research funded by NASA since the last 25 years in this field.

A team from the University of Rochester Medical Center (URMC) Department of Neurobiology and Anatomy, led by M. Kerry O’Banion, M.D., Ph.D., which has been working with NASA for over eight years, focused on the impact of high-mass, high-charged (HZE) particles. Unlike hydrogen protons that are produced by solar flares and which astronauts can take precautions against with appropriate warning, HZE particles are propelled through space at very high speeds from the force of exploding stars. They come in various forms, including iron particles, which is the one the researchers chose to examine.
“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.”

As a part of the research, mice were exposed to various levels of various radiations, and then tested for various cognitive faculties, in which many irradiated ones failed.The brains of the mice also showed signs of vascular alterations and a greater than normal accumulation of the protein “plaque” beta amyloid, the accumulation of which is a hallmark 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.”

This  sure is a concern for NASA , who are planning for a manned mission to mars in 2025, and will have to start thinking of ways to prevent from this soon, soon enough for its efficacy to be verified as well in time.
The team’s study appears in the journal PLOS ONE.
Source: University of Rochester Medical Center, Gizmag

The best NASA images from 2012

August 31, 2012: A solar filament erupts out into space (Image: NASA/GSFC/SDO

2012 saw a number of significant milestones in star gazing and space exploration. NASA's Mars rover Curiosity touched down on the Red Planet in spectacular fashion, super-Earth's were discovered, the Moon pounded and Voyager 1 edged ever closer towards interstellar space and we saw more of the universe around us than ever before

As the calendar rolls over, NASA’s Goddard Space Flight Center has put together an album of its top images for 2012. We’ve also picked our NASA favorites, highlighting some of the fascinating discoveries and incredible imagery captured in the skies above during the last twelve months.

March 26, 2012: Hubble Space Telescope captures the spiral galaxy NGC 2683, seen almost edge-on (Image: ESA/Hubble & NASA)

August 31, 2012: A region to the northwest of Mercury's crater Magritte – the shadowing helps define the "Mickey Mouse" resemblance, created by the accumulation of craters (Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

High-resolution self-portrait by Curiosity Rover arm camera, used by NASA engineers to document the rover’s condition (Image: NASA/JPL-Caltech/Malin Space Science Systems)

April 18 - October 23, 2012: This new image of Europe, Africa, and the Middle East at night is a composite assembled from data acquired by the Suomi NPP satellite (Image: Suomi NPP - VIIRS)

You can watch more of these here
Source: NASA Goddard Space Flight Center

Only 12 light years distant, two super-Earths orbit in Tau Ceti's habitable zone

Artist's conception of the five-planet Tau Ceti system (Photo: J. Pinfield/RoPACS/University of Hertfordshire)

Our stellar neighborhood is becoming crowded courtesy of some newly discovered real estate. Astronomers have uncovered evidence buried in the noise of apparently empty data showing that five super-Earths are orbiting the nearby Tau Ceti – a star chosen as one of the targets in the pioneering 1960 Project OZMA search for extraterrestrial life because of its strong similarity to the Sun. Better yet, the two outermost of Tau Ceti's planets appear to be in the star's habitable zone, making them the closest known potentially habitable exoplanets.

Astronomer Mikko Tuomi of the University of Hertfordshire and his colleagues analyzed more than 6000 prior spectroscopic observations of Tau Ceti. Delving deeply with powerful Bayesian analysis methods, they were looking for evidence that the star was being pulled from side to side by the gravitational influence of one or more orbiting planets.

They found it in spades. The best fit to the data suggests that Tau Ceti is orbited by five planets, all residing closer to Tau Ceti than Mars does to the Sun. The tally reads like this:

Planet.....Orbit Radius (AU).....Orbital Period (days)......Mass (Earths)
• TC b.................0.105........................14 days.........................2.0
• TC c.................0.195........................35 days.........................3.1
• TC d.................0.374.......................94 days........................3.6
• TC e.................0.552......................168 days........................4.3
• TC f..................1.35.........................642 days........................6.6

The planetary orbits are all very close to circular.

Comparison of the smaller Tau Ceti to the Sun. It is a bit smaller, cooler, and more stable than the Sun (Photo: R.J. Hall)

Tau Ceti is the twentieth closest star to our Sun, being a mere 11.9 light years distant. It closely resembles the Sun (unlike most stars) being a bright G-class star, with a mass of 0.78 solar masses, radius of 0.793 solar radii, and a luminosity of about half that of the Sun. It is older than the Sun by over a billion years, and is extremely stable, showing little variation or evidence of sunspots or flares.

Aside this small difference in size, the main distinction is that Tau Ceti is lacking in metals compared to the Sun, a factor probably leading to formation of less rocky planets than in our solar system. Because of this, Dr. Tuomi says: "It is impossible to tell the composition (of Tau Ceti e), but I do not consider this particular planet to be very likely to have a rocky surface. It might be a 'water world,' but at the moment it's anybody's guess."

Because Tau Ceti has only 55 percent of our Sun's brightness, the habitable zone lies closer than it does to our Sun. Despite this, the three innermost planets around Tau Ceti will be too hot to support life – Tau Ceti d's orbit is equivalent to an orbit around our Sun midway between Venus and Mercury.

The outer two planets are potentially habitable. Tau Ceti e falls clearly within the Core Habitability Zone, that being the region within which a planet like Earth will have liquid water. The Planetary Habitability Laboratory(U Puerto Rico, Arecibo) notes that both Tau Ceti e and f fall within the Extended Habitability Zone where larger planets with thicker atmospheres might retain sufficient heat for water to be liquid.

"They're pushing the envelope," says Gregory Laughlin, an astronomer at the University of California, Santa Cruz. "Some or even many of these planets could go away. But I think that they've done absolutely the best job that you can do, given the data. You have to get tons and tons and tons of velocity measurements over many years, and then you really, really have to take extreme care—as this Tuomi et al. paper does—to get rid of all the systematic noise."

Source: University of Hertfordshire (PDF) via Space.com

GRAIL spacecraft hit lunar mountain

The impact point of the GRAIL spacecraft (Image: NASA/JPL-Caltech/GSFC/ASU)

NASA’s two Gravity Recovery and Interior Laboratory (GRAIL) spacecraft have struck the Moon in a controlled impact. At 5:28:46 EST (222846 GMT) Ebb, the first spacecraft, struck a mountain near the lunar North Pole. The second, Flow, hit about 20 seconds later. Because the impact occurred during a new moon, no images were available of the impact, though NASA was able to determine the time of the event by monitoring the moment that telemetry ended. The Jet Propulsion Laboratory in Pasadena, California provided live television and online commentary.

The GRAIL spacecraft were launched in September 2011 and had completed their mission to map lunar gravitational anomalies as part of an effort to complete the most detailed gravity map of any body in the Solar System. On December 14, the spacecraft fired their engines to set them on their fatal trajectory. On December 15, the twin probes’ experiments were switched off. Earlier today, the spacecraft fired their engines for the last time to empty their fuel tanks so that engineers could determine how much was left.

Artist's concept of the GRAIL spacecraft (Image: NASA)

The purpose of the controlled impact was to ensure that the probes didn’t crash near any historic Russian or American landing sites on the Moon. Because of their low orbit, the GRAIL spacecrafts’ orbits would have soon decayed, bringing them down naturally.

This is not the first time such controlled impacts have been made on the Moon. The first unmanned spacecraft to reach the satellite in 1959, the USSR’s Luna 2, was sent on a collision course because the technique of going into orbit around the Moon hadn’t been perfected yet. Since then, other unmanned or abandoned manned spacecraft have been sent to hit the Moon either as part of a photo reconnaissance mission, to learn more about the surface, to cause shock waves for seismic studies or to reduce the amount of space debris in lunar orbit.

The impact site of the GRAIL spacecraft is latitude 75.62° N, longitude 26.63° E in the vicinity of Goldschmidt crater. When day returns to the site, NASA’s Lunar Reconnaissance Orbiter (LRO) will survey the area. After the impact, NASA announced approval for naming the impact site “Sally Ride” after the late U.S. astronaut.

The animation below shows the final seconds of the GRAIL spacecraft’s orbit.

Source: NASA , Gizmag

Voyager 1 gets a taste of interstellar space

NASA's Voyager 1 spacecraft exploring a new region in our solar system called the 'magnetic highway' (Image: NASA/JPL-Caltech)

Voyager 1 has reached yet another new frontier on its historic journey towards the edge of our solar system. NASA scientists believe this “magnetic highway” represents the final region the spacecraft must cross before becoming the first man-made object to reach interstellar space, an event they are guessing could be as close as a couple of months away.

After Voyager 1 crossed the termination shock into the outer layer of the heliosphere known as the heliosheath in December 2004, the stream of charged particles from the sun (known as the solar wind) abruptly slowed down from supersonic speeds and started bouncing around in all directions.In June 2010, when it was about 17 billion kilometers (10.7 billion miles) from the sun, the outward speed of the solar wind finally slowed to zero and the intensity of the magnetic field experienced by the spacecraft also began to increase.

On July 28, 2012, data from Voyager 1’s onboard instruments that measure charged particles showed the spacecraft had entered a new region for the first time. Here, our sun’s magnetic field lines are connected to interstellar magnetic field lines, which allows lower-energy charged particles originating from the sun to zoom out and higher-energy particles from interstellar space to stream in – hence the “magnetic highway” moniker. The region ebbed and flowed towards Voyager 1 several times before becoming stable on August 25.

"If we were judging by the charged particle data alone, I would have thought we were outside the heliosphere," said Stamatios Krimigis, principal investigator of the low-energy charged particle instrument, based at the Johns Hopkins Applied Physics Laboratory, Laurel, Md.

However, the Voyager team believes it is still inside the heliosphere because the direction of the magnetic field lines hasn’t changed. They expect this to change once Voyager 1 crosses over into interstellar space.

"Although Voyager 1 still is inside the sun's environment, we now can taste what it's like on the outside because the particles are zipping in and out on this magnetic highway," said Edward Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "We believe this is the last leg of our journey to interstellar space. Our best guess is it's likely just a few months to a couple years away. The new region isn't what we expected, but we've come to expect the unexpected from Voyager."

Now about 18 billion kilometers (11 billion miles) from the sun, Voyager 1 is the most distant human-made object, with a signal from the spacecraft taking approximately 17 hours to travel to Earth.

Source: NASA/JPL-Caltech , Gizmag