Feeds

Cosmic rays hit Space Age high

Deflector shields activated, Mr Sulu?

The next step in data security

The level of cosmic rays bombarding our solar system has hit a 50-year high - a "signficant" increase which could impact on future space missions.

The surge in cosmic rays - "subatomic particles, mainly protons but also some heavy nuclei", Space.com explains - was detected by NASA's Advanced Composition Explorer (ACE) spacecraft.

Richard Mewaldt of Caltech elaborated: "In 2009, cosmic ray intensities have increased 19 per cent beyond anything we've seen in the past 50 years. The increase is significant, and it could mean we need to rethink how much radiation shielding astronauts take with them on deep-space missions."*

The reason for the livelier cosmic ray levels is the current solar minimum. This lull in the Sun's activity means "flagging" solar winds and, as a result, a reduced heliosphere. Mewaldt explained: "Measurements by the Ulysses spacecraft show that solar wind pressure is at a 50-year low, so the magnetic bubble that protects the solar system is not being inflated as much as usual."

Accordingly, cosmic rays have a "shorter shot into the solar system", and once they enter the heliosphere, face weaker solar winds to impede their progress.

The rays are also less prone to interference from the "heliospheric current sheet" - a complex surface described as resembling a "ballerina's skirt", wrapped round the Sun and extending from its equatorial plane. The current sheet marks the boundary in the Sun's magnetic field where its polarity changes from north to south.

The current sheet's "folds" affect the progress of cosmic rays, but it's now "flattening itself out", allowing the charged particles "more direct access to the inner solar system".

Mewaldt noted: "If the flattening continues as it has in previous solar minima, we could see cosmic ray fluxes jump all the way to 30 percent above previous Space Age highs."

None of this, however, poses a serious threat to Earth. While a single cosmic ray could conceivably, if it hit the right spot, knock out a satellite's electronics, the present cosmic ray high is considerably lower than our planet has experienced in the past.

The proof comes in the form of an isotope of beryllium, 10Be, created by cosmic rays when they impact with Earth's atmosphere, and preserved in polar ice. Tests on ice cores have shown that "hundreds of years ago, cosmic ray fluxes were at least 200 per cent higher than they are now".

Mewaldt concluded: "The space era has so far experienced a time of relatively low cosmic ray activity. We may now be returning to levels typical of past centuries." ®

Bootnote

*Well, the way things are going at the moment, this won't be an issue, since the Sun will have reached solar maximum by the time we get our act together and head off to Mars.

New hybrid storage solutions

More from The Register

next story
PORTAL TO ELSEWHERE scried in small galaxy far, far away
Supermassive black hole dominates titchy star formation
Bacon-related medical breakthrough wins Ig Nobel prize
Is there ANYTHING cured pork can't do?
Boffins say they've got Lithium batteries the wrong way around
Surprises at the nano-scale mean our ideas about how they charge could be all wrong
Edge Research Lab to tackle chilly LOHAN's final test flight
Our US allies to probe potential Vulture 2 servo freeze
Europe prepares to INVADE comet: Rosetta landing site chosen
No word yet on whether backup site is labelled 'K'
Stray positrons caught on ISS hint at DARK MATTER source
Landlubber scope-gazers squint to horizons and see anti-electron count surge
Cracked it - Vulture 2 power podule fires servos for 4 HOURS
Pixhawk avionics juice issue sorted, onwards to Spaceport America
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.