Christmas solar plasma belches to hit Earth, Mars - and Mars rover in space

Sun emits festive eruptions, but no bad effects foreseen

In tune perhaps with the festively-overtaxed digestive processes of many Register readers and hacks, the Sun has lately been giving vent to frightful burning eruptions of internal gas; ones sufficiently awful to mean fatal consequences for unprotected humans in their path.

Fortunately (in the case of the Sun at least) there are no such exposed bystanders. The human race, as it has done for almost its entire history*, is sheltering within the protective magnetic fields of old Earth and top solar boffins expect these to withstand the incoming plasma belches with barely a flicker. An unruffled statement regarding Christmas and Boxing Day Coronal Mass Ejections (CMEs) hurled out from the Sun toward Earth issued by the US Space Weather Prediction Centre says:

Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels with a chance for isolated minor storm levels on day one (29 December) as multiple CMEs are expected to arrive. Quiet to unsettled level are expected on day two (30 December) as effects the previous CMEs wane. Predominantly quiet levels are expected on day three (31 December).

"Minor storm levels" mean no serious consequences, as we can see from the official solar Beaufort-scale equivalent here, so there appears to be nothing much to worry about for us Earthlings - though residents of northern latitudes may see some better aurorae than usual.

However the festive solar indigestion eruptions have consequences for other planets than Earth, and for interplanetary spacecraft. Experts at the sun-watching site have noted that one of the big Christmas CMEs can also be expected to play its heated breath across Mars, with the first gusts of plasma striking on December 30. The solar squalls can also be expected to strike the new nuclear-powered, raygun-wielding Mars rover Curiosity, currently outward bound in its carrier spacecraft for a landing on the red planet next August.

Again, there's no need to fret it seems. NASA tells us:

Encounters with CMEs pose little danger to Curiosity. By the time a CME reaches the Earth-Mars expanse, it is spread so thin that it cannot truly buffet the spacecraft.

However the rover may well be able to get in a bit of useful science before even arriving on Mars, as it could sniff the roaring plasma gusts as they roll across its track using its coffee-tin sized Radiation Assessment Detector instrument. This would not only be of interest to solar physicists, but also to boffins planning future interplanetary manned missions: Curiosity being sealed up inside its spacegoing, re-entry-capable aeroshell, the dose of radiation it receives during its journey would furnish a good guide to that which a Mars-naut of the future riding in a comparably-constructed ship might sustain.

Even if the new and much more capable rover doesn't manage a successful landing in the red planet's Gale Crater, it will have delivered some handy knowledge already. ®


*The one exception being the Apollo astronauts of long ago, who ventured briefly out from beneath the mother planet's protective apron to visit the Moon. No other human beings have been beyond low orbit, where the planetary magnetic field still offers strong protection.

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