Space Weather Is Getting Worse

Our sun has been more active lately as it enters a new phase in its 11-year cycle, which is one reason we’ve seen a bunch of enormous coronal mass ejections and solar explosions in the past few months. But it’s actually a pretty weak solar maximum, as solar maximums go, so heliophysicists believe the sun is entering a prolonged hibernation unseen since the 17th century. This has some major implications for climate changes — on Earth and in the heavens, according to one new study.

A chilled-out sun would spew fewer particles into space, meaning the sun’s protective moat around the solar system would be less powerful. Galactic cosmic rays could have an easier time getting through, which means they could pose an increased radiation risk to astronauts and air passengers. Under these space weather conditions, a crewed asteroid or Mars mission would be far more dangerous, if not impossible.

This makes sense, given the sun’s role in shielding Earth from invading galactic particles. Charged particles from the sun encase the entire solar system in a protective sheath called the heliosphere. Scientists believe frothy bubbles of charged particles create a moat at the border between the sun's sphere of influence and that of interstellar space; cosmic rays from other stars have a hard time getting across. But when the sun is less active, this moat, called the heliosheath, is weaker. 

To test whether this is really happening, you would need to study galactic cosmic ray penetration over the centuries. Michael Lockwood and colleagues at the University of Reading in the United Kingdom looked at a 9,300-year record from ice core samples from the north and south poles. 

Galactic cosmic rays and solar energetic particles tend to channel at the poles, and Lockwood et. al looked for different chemicals that serve as a proxy for cosmic ray and SEP abundance. They found in times of low solar activity, more galactic cosmic rays reach the Earth, and there were fewer SEP events, according to ScienceNow. But in an odd twist, they also noted that the SEP events were more intense. This was especially true during transition times — just like the one we’re thought to be in right now. So just as the sun is letting more particles cross its moat, it, too, is spewing out more harmful stuff. 

The study was published in the journal Geophysical Research Letters.

Solar physicists say this could expose astronauts to unsafe levels of radiation, especially astronauts leaving the protective influence of Earth’s own magnetic field. Lockwood believes radiation exposure could increase two-fold during this solar hibernation, according to ScienceNow. And that hibernation could last between 40 and 200 years, so a Mars mission might be even further out than we all hoped.

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Posted in: charged particles,coronal mass ejection,cosmic rays,mars,solar energetic particles,solar explosions,space,Space Weather Is Getting Worse

Mega Space Storm Could "Block" Us Here On Earth For A Decade

A MAJOR solar storm would not only damage Earth's infrastructure, it could also leave a legacy of radiation that keeps killing satellites for years.

When the sun belches a massive cloud of charged particles at Earth, it can damage our power grids and fry satellites' electronics. But that's not all. New calculations suggest that a solar megastorm could create a persistent radiation problem in low-Earth orbit, disabling satellites for up to a decade after the storm first hit.

It would do this by destroying a natural buffer against radiation - a cloud of charged particles, or plasma, that normally surrounds Earth out to a distance of four times the planet's radius.

The relatively high density of plasma in the cloud prevents the formation of electromagnetic waves that would otherwise accelerate electrons to high speeds, turning them into a form of radiation. This limits the amount of radiation in the innermost of two radiation belts that surround Earth.

But solar outbursts can erode the cloud. In October 2003, a major outburst whittled the cloud down so that it only extended to two Earth radii. A repeat of a huge outburst that occurred in 1859 - which is expected - would erode the cloud to almost nothing.

Yuri Shprits of the University of California in Los Angeles led a team that simulated how such a large storm would affect the radiation around Earth.

They found that in the absence of the cloud, electromagnetic waves accelerated large numbers of electrons to high speed in Earth's inner radiation belt, causing a huge increase in radiation there. The inner radiation belt is densest at about 3000 kilometres above Earth's equator, which is higher than low-Earth orbit. 

But the belt hugs Earth more tightly above high latitude regions, overlapping with satellites in low-Earth orbit.

Speeding electrons cause electric charge to accumulate on satellite electronics, prompting sparks and damage. Increasing the number of speeding electrons would drastically shorten the lifetime of a typical satellite, the team calculates (Space Weather, DOI: 10.1029/2011sw000662).

The researchers say that the destructive radiation could hang about for a long time, spiralling around Earth's magnetic field lines. In 1962, a US nuclear test carried out in space flooded low-Earth orbit with radiation that lasted a decade and probably ruined several satellites.

"When you get this radiation that far in, it tends to be quite long-lived and very persistent," says Ian Mann of the University of Alberta in Edmonton, Canada, who was not involved in the study.

Thicker metal shielding around satellite electronics would help, says Shprits. The persistent radiation would also be hazardous for astronauts and electronics on the International Space Station.

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Posted in: charged particles,earth,electromagnetic waves,electronics,Mega Space Storm Could "Block" Us Here On Earth For A Decade,solar flare,solar storm,statellites