C/2013 A1 (Siding Spring) is scheduled for a very close flyby at only about 139 500 km (88 000 miles) away from the surface of Mars on October 19, 2014 around 18:27 UTC. That is less than half the distance between Earth and its moon and less than one-tenth the distance of any known comet flyby of Earth. 

The comet is expected to flyby at about 56 kilometers per second (126 000 mph), relative to Mars, enveloping the Red Planet in its dusty coma as it goes by. It will not hit Mars, but questions still remain about the potential risks to the Mars spacecraft from the dust and particles released by the passing comet.

There are currently five spacecraft in Mars's orbit. One from India (Mars Orbiter Mission), one from the European Union (Mars Express) and three from the United States (MOD, MRO, MAVEN) + two Mars rovers (Curiosity and Opportunity). They will all try to take a close look at this historic flyby.

The period of greatest danger is when Mars comes closest (around 27 600 km) to the comet's trajectory, and not when the comet's nucleus comes closest to the planet. This is about 90 minutes after the closest app...

A very strong and shallow M7.1 earthquake was registered in the southern East Pacific Rise (Challenger Fracture Zone) on October 9, 2014 at 02:14 UTC. USGS is reporting depth of 15.5km (9.6 miles). The quake was followed by several strong aftershocks. The southern stretch of the East Pacific Rise is one of the fastest-spreading sections of the Earth's mid-ocean ridge system.

Epicenter was located 565 km (351 miles) SSW of Hanga Roa, capital of the Chilean province of Easter Island, and 3 426 km (2 129 miles) W of Lebu, Chile.

There are no people living within 100 km radius.

A tsunami wave amplitude of 0.47 m at Easter Island was reported by the Chilean Navy. (PTWC)

Image credit: USGS

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The origin and mechanism of sunspots, solar flares and heating of the corona to millions of degrees remains a mystery under the current standard solar model. In the past 95 years several theories were proposed, but none could really explain the origin and how the Sun’s magnetic field is generated.

The first serious theory that tried to solve this problem was introduced by Larmor in 1919. He proposed that the motion of charged particles on the solar surface create magnetic fields, like current flowing in a wire. But this was soon dismissed by T.S Cowling on the grounds that these "dynamo fields" cannot be self-sustaining due to the resistance of the solar gases. In other words, the solar plasma would dissipate the magnetic fields almost as quickly as they tried to form.

Early in the second half of the 20th century, Eugene Parker proposed another solution to the solar magnetic fields. This became known as the "Parker Solar Dynamo Theory". Parker’s theory was based on the idea that currents of charged particles in the convective zone would induce magnetic fields and these fields would rise to the surface. Along the way t...