Monday, June 09, 2014

Wanderlust: A bum rush!

Solid bodies in the Solar System are relatively few; IMO the inner planets, asteroids, comets, and a few satellites around the Gas Giants. To the best of my knowledge, asteroids & comets lack an atmosphere - and are pock-marked to the extreme.

Out of Mars, Earth, Venus & Mercury - Mercury's atmosphere is ... mercurial, the Venerean atmosphere is lush in the extreme. Mars has a thin atmosphere, whereas Earth's is (for us humans, and a few other species) just right.

Of these 4 terrestrial planets, Earth has the greatest escape velocity at 11.2 km/s followed closely by Venus 10.3km/s, Mars 5km/s, and finally Mercury 4.3km/s.

At it's closest, Venus is around 38 Million km from Earth. Mars is around 54.6 million kilometers in it's turn.

No body is immune to impact by other bodies. Earth too is no stranger to body-play; Micro-micro meteorites accumulate by the giga-ton annually in the form of dust. Larger impact bodies such as the Chicxulub capable of delivering several as much as 100 Teratons equivalent of TNT are also out there - but less frequent. As many as 132 meteorites found on Earth are identified as of Martian origin.

On October 17, 2013, NASA reported, based on analysis of argon in the Martian atmosphere by the Mars Curiosity rover, that certain meteorites found on Earth thought to be from Mars were actually from Mars.


Back in the 1960s/70s, Project Orion was a theoretical study on a nuclear pulse propelled space-ship. Several devices being flung out opposite to the desired direction of thrust. Each device imparting an absurdly humongous specific impulse on detonation.

What I therefore find myself wondering

  1. How large would the impact have been on Mars to impart escape velocity to the rocks that eventually turned up on Earth?
  2. Even given the turbulent environment on Mars, is there a possibility one of the impact craters - the source of an eventual martian meteorite, may be discovered by one of the missions presently on/under-way to Mars?
  3. Is there a probability of discovering a Venerean meteorite here on Earth?
  4. Could Chicxulub, or a comparable impact may have dislodged a rock and sent it to Mars, or Venus?

 

Sunday, June 08, 2014

Wanderlust: Kayoed

The Solar System is comprised of the Sun, Jupiter, and other debris of creation. A portion of the debris are called planets; these are broadly classified as Gas Giants (Jupiter Saturn Uranus & Neptune ), and Terrestrials  (Mercury, Venus, Earth, Mars).

A planet usually has reasonably well-defined orbit. Smaller bodies have a well-defined orbit too, but are more liable to suffer perturbation from larger bodies. These smaller bodies are either comets, or asteroids.

Wikipedia has a great article on meteorites This article defines a meteorite as below

A meteorite is a solid piece of debris, from such sources as asteroids or comets, that originates in outer space and survives its impact with the Earth's surface.

But there are also the rare meteorites that may have originated on Mars. The wikipedia  article on Martian meteorite writes to say

On October 17, 2013, NASA reported, based on analysis of argon in the Martian atmosphere by the Mars Curiosity rover, that certain meteorites found on Earth thought to be from Mars were actually from Mars.

This raises a few questions in my mind

a. Do these martian meteorites contain significant quantities of extra-martian particles? (E.g. Those that belonged to the original asteroid/meteorite which impacted Mars, OR those that were collected during the course of it's journey through space)

b. How much velocity, and mass would the original meteorite have had to impart escape velocity to the rock? Is it possible to formulate these figures & say if a comet has mass X, and velocity Y it may impart escape velocity to Z mass of the impacted body?