Friday, October 7, 2011

The Latest Among The Planets

Much has been happening these days, concerning the planets, that is. MESSENGER found a lot of what Mars is like, needless to mention Dawn's secrets from Vesta. Mars and Venus have some stories of their own to tell, again, let alone Uranus. Ever since the beginning when MESSENGER started spewing our information about Mars, much more was happening than I though; nothing is of the sort redundant - the planets can never lie! (Although this is not in the least a comprehensive study of each of the planet's latest 'whereabouts,' this article does bring forth the best of each planet.)

MESSENGER Spreads the Real Mercury

Six months have gone by since MESSENGER was put into orbit around Mercury, and has finished a set of orbits that have been necessary for astronomers to learn more about this baked planet. Sky & Telescope write this about Mars: "its exterior bears only slight geochemical resemblance to the outer layer of Mars and to the seafloor crust on Earth and none at all to the Moon's low-density, metal-poor crust. Instead, the combination of a high magnesium-to-silicon ratio and an abundance of the 'volatile' rock-forming elements sodium, potassium, and sulfur make Mercury unique among the terrestrial worlds."

There are many radioactive isotopes in the crust, as MESSENGER has found potassium and uranium to name a few. MESSENGER would not have found these foundational elements if not for the strong gamma ray flow they produced - quite amazing for Mercury. But, what really shocked astronomers was the core of this sullen planet. It takes up three-fourths the diameter of the planet (and nearly half Mercury's entire volume!), and is very metallic, to leave alone to the fact that the surface is very low in metallics (specifically iron). This view changed the entire way astronomers now thing about this planet - you can read and see more at MESSENGER's website, where feeds of images report back to earth daily.

Venus' New Ozone Layer

"The European Space Agency's Venus Express spacecraft has discovered an ozone layer high in the atmosphere of Venus," Science Daily tells us. Now we know that like earth, Venus too has an ozone layer; maybe this is to blame for the cloudy atmosphere? Although astronomers aren't sure of it yet, they are hoping this may lead them to finding life on other planets, which is rather amazing to note, considering how Venus Express made this fascinating discovery. "Venus Express made the discovery while watching stars seen right at the edge of the planet set through its atmosphere. Its SPICAV instrument analysed the starlight, looking for the characteristic fingerprints of gases in the atmosphere as they absorbed light at specific wavelengths."

It's a very incredible thing that Venus Express could see Venus occult stars, and then noticing that they weren't fully occulted! (they could still be seen through the atmosphere). This is what astronomers have been waiting for, becasue it may show us how they can see if there is life on other planets - the presence of ozone. We now know that three planets in the solar system block the powerful rays of radiation the Sun emits, earth, Mars, and now Venus. Through the different chemicals, astrobiologists believe that this (simultaneous) presence of those different chemicals, respectively oxygen, carbon dioxide, etc., may tell us if there could be life on a planet.

"This ozone detection tells us a lot about the circulation and the chemistry of Venus' atmosphere" says HÃ¥kan Svedhem, ESA Project Scientist for the Venus Express mission. "Beyond that, it is yet more evidence of the fundamental similarity between the rocky planets, and shows the importance of studying Venus to understand them all."

Mars' Supersaturated Water Vapor: the Red Planet has Water After All!

European Space Agency's Mars Express spacecraft (I presume it's twin is European Space Agency's Venus Express spacecraft, above) has found water on Mars. Although this is a little too bluntly stated, the spacecraft does show us that there is supersaturated water on the planet, in it's atmosphere, respectively. To define things clearer, "supersaturated" is the past participle (or as us Latinists would call it the 'perfect passive participle') of the verb, to "supersaturate" and is defined from Merriam-Webster, "to increase the concentration of (a solution) beyond saturation point," or in a more astronomical sense, "water that is suspended in Mars' atmosphere, with increased concentration beyond the saturation point."

Hypothetical water transport in the Martian atmosphere

You may ask, how can this be? To show correlation, on earth, water vapor in the atmosphere condenses when the temperature is lower than the standard dew-point. When the atmosphere is so saturated with all this condensed water attaching to dust particles (which make it heavier), it rains. This is not what happens on Mars. Science Daily writes, "condensation may sometimes be much slower, especially when particles and dust are scarce. Unable to condense, the excess water vapor therefore remains in the gaseous state: this is known as supersaturation. Until now, it was assumed that this phenomenon could not occur in the Martian atmosphere, although this had never been proved."

(Hence, later on, Science Daily writes that this hypothesis needs revising, but is a good start to this never-ending debate: does Mars have water, (or more spontaneously) life!?)

As we reminisce on the planets, astronomers look now at Mercury's formation in a different way, Venus' atmosphere may help them find more life, and so might the "water vapor" on Mars. Although nothing big happens with Saturn, Neptune, Pluto (and/or Ceres & Eris), we will start some Jovian transits soon, respectively on Jupiter... Uranus has another story as well. Astronomers think that Uranus' tilt was casued by a different can read here. (It is written in an evolutionary perspective).

(Credit: Lawrence Sromovsky, (Univ. Wisconsin-Madison), Keck Observatory)

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