Apocalypse News: Sun’s Magnetive Field about to Flip

sun_magneticfieldThe sun is set to reverse its polarity in the next few months, something that occurs at the height of every Solar Cycle. The resulting ripple effect will be felt all across the Solar System and will even be detectable by the far-away Voyager probes. However, scientists are telling us not to fret, as this event will not lead to the end of the world.

In truth, the Sun’s reversal of polarity is something that occurs every 11 years. And the shift won’t spark an increase in powerful solar storms or other events that could have a damaging effect on Earth and its inhabitants, say the researchers. One such researcher is Phil Scherrer, a solar physicist at Stanford University, who insisted “The world will not end tomorrow.”

NASAsolar_radiationIn addition, from a human perspective, the effects of the field shift will likely be slight and even beneficial. For example, the polarity reversal will cause the “current sheet” – an enormous surface extending out from the solar equator on which the sun’s rotating magnetic field has induced an electric current – to become much wavier.

This crinkled current sheet, in turn, will provide a better barrier against galactic cosmic rays, high-energy particles that are accelerated to nearly the speed of light by faraway star explosions. Galactic cosmic rays can damage spacecraft and hurt orbiting astronauts who don’t get to enjoy the protection of Earth’s thick atmosphere. So for space exploration, at any rate, this is certainly good news.

Sun's Heliospheric-current-sheetAccording to Todd Hoeksema, director of Stanford’s Wilcox Observatory, a drop in galactic cosmic ray levels could also have a subtle impact on weather here on Earth.

One of the things that helps clouds form and lightning to flash is cosmic-ray ionization of things in the Earth’s atmosphere. So when the cosmic-ray intensity is lower, it means you have fewer places where lightning will occur, and so the storms will probably be a little less intense.

He added, however, that it’s pretty much a speculative endeavor at this point, as no conclusive link has ever been demonstrated between cosmic rays and the weather.

In any case, during a reversal, the sun’s polar magnetic fields weaken all the way down to zero, then bounce back with the opposite polarity. Researchers will keep a keen eye on just how strong this recovery is over the next two years or so. The sun has been quiet during its current 11-year activity cycle, which is known as Solar Cycle 24. So it would be particularly interesting to see a strong field emerge after the impending flip.

sun_magneticfield1Dean Pesnell, a project scientist for the space agency’s Solar Dynamics Observatory spacecraft at NASA’s Goddard Space Flight Center, the Sun’s latest field is likely to be a good indicator of what the next solar cycle is going to do. During its most recent cycle, known as Solar Cycle 24, the sun was rather quiet, so what happens next ought to be interesting:

If it quickly goes to a high value, then that tells us the next cycle will be high. We’ve had several of these solar minimums, and each time the polar field has been weaker. And each time, the next cycle has been a little bit weaker. So it would be nice to see one where the polar field strength was higher, and the next cycle was higher as well.

So rest easy, folks. No apocalyptic scenarios are likely to result from this latest, all-too-common solar phenomena. If anything, it will provide research benefits for scientists and aid in space exploration – especially for companies looking to mount missions to Mars in the next 11 years and trying to figure out a way around that tricky radiation problem.

As for the rest of us, we’re likely to maybe get a little break on the weather front. Maybe not. Kind of disappointing when you think about it…

But at least there’s a helpful video provided by Space.com. Enjoy!


Source:
space.com

News From Mars: Revelations on Radiation

mars_astronauts1As the projected date for a manned mission to the Red Planet approaches, the Mars Science Laboratory and Curiosity team continue to conduct vital research into what a human team of explorers can expect to find. Unfortunately, earlier last month, that research led to a discouraging announcement which may force NASA and a number of private companies to rethink their plans for manned missions.

Earlier in May, a number of scientists, NASA officials, private space company representatives and other members of the spaceflight community gathered in Washington D.C. for a three day meeting known as the Humans to Mars (H2M) conference. Hosted by the spaceflight advocacy group Explore Mars, the attendees met to discuss all the challenges that a 2030 manned mission would likely encounter.

mars_astronautsFor starters, the human race currently lacks the technology to get people to Mars and back. An interplanetary mission of that scale would likely be one of the most expensive and difficult engineering challenges of the 21st century. Currently, we don’t have the means to properly store enough fuel to make the trip, or a vehicle capable of landing people on the Martian surface. Last, and most importantly, we aren’t entirely sure that a ship will keep the astronauts alive long enough to get there.

This last issue was raised thanks to a recent confirmation made by the Curiosity rover, which finished calculating the number of high-energy particles that struck it during its eight month journey to Mars. Based on this data, NASA says that a human traveling to and from Mars could well be exposed to a radiation dose that is beyond current safety limits.

NASAsolar_radiationThis was performed with the rover’s Radiation Assessment Detector (RAD) instrument, which switched on inside as the cruise vessel began its 253-day, 560-million-km journey. The particles of concern fall into two categories – those that are accelerated away from our Sun and galactic cosmic rays (GCRs) – those that arrive at high velocity from outside of the Solar System. This latter category is especially dangerous since they impart a lot of energy when they strike the human body, can cause damage to DNA and are hard to shield against.

What’s more, this calculation does not even include time spent on the planet’s surface. Although Curiosity has already determined that planetary levels were within human tolerances, the combined dosage would surely lead to a fatal case of cancer for any career astronaut looking to take part in an “Ares Mission”. Cary Zeitlin from the Southwest Research Institute in Boulder, Colorado, and colleagues reported the Curiosity findings in the latest edition of Science magazine.

They claim that engineers will have to give careful consideration to the type of shielding that will need to be built into a Mars-bound crew ship. However, they concede that for some of the most damaging radiation particles, there may be little that can be done, beyond delivering them to Mars as quickly as possible. This presents an even greater challenge, which calls for the development of something better than existing propulsion technology. Using chemical propellants, Curiosity made the trip in eight months.

spaceX_elonmusk However, the good news is that at this juncture, nothing is technologically impossible about a manned Mars mission. It’s just a matter of determining what the priorities are and putting the time and money into developing the necessary tools. Right now NASA, other space agencies, and private companies are working to bring Mars within reach. And with time and further developments, who knows what will be possible by the time the 2020’s roll around?

Some alternatives include plasma and nuclear thermal rockets, which are in development and could bring the journey time down to a number of weeks. What’s more, SpaceX and other agencies are working on cheaper deliver systems, such as the grasshopper reusable rocket, to make sending ships into space that much more affordable. In addition, concepts for improving radiation shielding – like Inspiration Mars’ idea of using human waste – are being considered to cut down on the irradiation factor.

So despite the concerns, it seems that we are still on track for a Mars mission in 2030. And even if there are delays in the implementation, it seems as though a manned mission is just a matter of time at this point. Red Planet, here we come!

Sources: bbc.co.uk, wired.com