Bakersfield Night Sky – November 5, 2011
By Nick Strobel
Well, the comet that was an internet sensation for all those suffering from "cosmophobia" (fear of the cosmos, particularly a fear that some astronomical object or event will bring about the end of the world) is now no more. Comet Elenin has broken up into thousands of tiny chunks on its closest passage to the Sun as happens with about two percent of the comets. The dirty iceberg that was Comet Elenin before the break-up was about 1.2 miles across. It was quite fragile as most comets are: chunks of ice, rock, dust and organic compounds loosely held together like dust balls. For some reason several bloggers latched on to Comet Elenin when it was discovered last December, predicting that the comet's gravity would wreak havoc on the Earth. When you calculate how much gravity the comet exerted on the Earth at its closest distance of about 22 million miles on October 16th when its gravity pull was greatest, it was less than the gravity pull of your car on the Earth. That, of course, did not stop all of the doomsday predictions and conspiracy claims of cover-ups by NASA. Sigh!
Surprisingly, I haven't heard much buzz about the asteroid 2005 YU55 that will buzz by Earth on November 8th (but perhaps I don't spend enough time in the "right" websites). The little asteroid is about 1300 feet across and is made of dark, carbonaceous material. It will get to within about 85% of the distance between us and the Moon. Though the effects of an impact would be very nasty indeed, there is zero chance of 2005 YU55 hitting us in the next 100 years. No, the gravity of this asteroid is much too small to produce any detectable effects on the Earth, including our tides or tectonic plates. You will need to use a telescope to see the little asteroid pass through Pegasus in the evening of November 8th. A finder chart is available as the second chart below. The next close approach of an asteroid will be when asteroid 2001 WN5 passes within 60% of the Moon's distance in 2028. If you read of doomsday reports on the internet about up-coming asteroid or comet collisions, follow the steps I outlined at the end of my July 16th column to sift out the grains of truth from the avalanche of hype.
The Mars Science Laboratory (MSL), named Curiosity, is scheduled to launch near the end of this month. The launch window is November 25th through December 18th. If it is able to launch during that time, it will arrive at Mars in August 2012. Curiosity will spend one martian year (almost two Earth years) exploring Gale Crater, a crater 96 miles across with a large mountain that appears to be the remnant of an extensive series of deposits. The layers at the base of the mountain contain clay and sulfates that very likely formed in liquid water. Curiosity will determine if that site could have supported life and if the conditions are right for preserving clues of any possible past life. It will have the instruments needed to find any organic molecules (meaning carbon-based molecules) in the rocks and soil. While Curiosity won't have the instruments to detect biological activity nor image microorganisms, it will be able to do an isotopic analysis of the carbon and other elements in the rocks to look for ratios of the isotopes that would be indicative of life or past life. Curiosity will also investigate: the geology of the area to figure out the rocks and soil formed; how the atmosphere has changed through time and the cycling of water and carbon dioxide; and the radiation environment at the surface (photons and particles from the Sun and the rest of the galaxy).
Curiosity will be using many new technologies invented by NASA/JPL engineers to explore Mars but what first got my attention when the MSL was first introduced to the public was the use of a Sky Crane as part of the landing process. Curiosity is twice as large and over five times more massive than previous Mars rovers. That's too big for the use of airbags to cushion the landing. When the descent stage has slowed to nearly zero speed, the rover will be lowered using a bridle and "umbilical cord". When Curiosity is on the ground, the bridle will be cut and the sky crane will power away to crash far from the rover. Yes, there's a lot of other cool technology on the MSL but that one still makes me go "whoa!" That one and the laser that will vaporize parts of rocks at a distance and take the spectrum of the vapor to see which rocks have interesting enough compositions to drive on over to for closer inspection. For more about the MSL, go to http://mars.jpl.nasa.gov/msl .
Back home in Bakersfield, tonight you may be able to spot Venus low in the southwest sky shortly after sunset with dimmer Mercury right below it. They will be the two brightest star-like objects low in the southwest. Though they set about an hour after the Sun does, we will still have look for them carefully against the bright twilight sky. They are now at the head of Scorpius but the twilight glow will probably wash out its stars. Shortly after sunset, you will see the Waxing Gibbous Moon high in the southeast and Jupiter will be rising in the east. The Moon and Jupiter are on opposite sides of Pisces but Pisces' stars are very dim and hard to see in the city. This early evening view of the sky is shown in the first star chart below. The southwest view of Venus and Mercury is shown in the inset.
Mars should be visible rising in the east at around 12:45 AM (standard time—daylight savings ends early Sunday morning!). It will be right above the bright star Regulus at the end of the Sickle of Leo with Mars the brighter of the two (and an orangish color to Regulus' blue-white color—see the third star chart below). Mars will be getting brighter over the next several months as we catch up to it in our faster orbit. Closest approach will be on March 3, 2012 but this close approach will not be like the past couple of ones. Unlike the past two close approaches, Mars will be near the farthest point of its elliptical orbit around the Sun when we pass by it, so Mars will not be as big (though I'm sure the "Mars as big as the Full Moon" email will still be going around) as it was during the other close approaches.
Later in the month, the Moon will be full on November 10th and at 3rd Quarter phase on November 18th. The morning of November 18th should be the peak of the Leonid meteor shower but the bright Moon will wash out the fainter meteors. The third star chart below shows Mars' and the Moon's positions along with the Leonid meteor shower radiant on November 18th. The radiant of a meteor shower is the position in the sky from which the meteors appear to streak.
Want to see more of the stars at night and save energy? Shield your lights so that the light only goes down toward the ground. See www.darksky.org for how.
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com