Bakersfield College

March 15, 2014

Bakersfield Night Sky – March 15, 2014
By Nick Strobel

Mid-March at 1 am, looking SoutheastIt is now less than one month away from the Astronomy Day that will take place on April 12th at the new Houchin Community Blood Bank at 11515 Bolthouse Drive (off of Buena Vista Rd between White Lane and Panama Lane). This Kern Astronomical Society event is free! In addition to the special speaker, Alex Filippenko, who will talk about dark energy and the accelerating universe, the tireless chair of the event, Carol Powers, has lined up Terry Himes from NASA's Jet Propulsion Laboratory to talk about "From Comets to Wheels on Mars!" after Filippenko's talk. The week buidling up to Astronomy Day will be the Astronomy Week blood drive at Houchin that will be launched on Monday, April 7th with a Solar Social from 4 to 7 PM. Pizza and snacks will be available at the social along with great views of our star, the Sun, through the KAS solar telescopes.

Another launch I'm looking forward to is the new Cosmos series. Being broadcast in primetime on Fox TV on Sundays and The National Geographic Channel on Mondays for thirteen weeks, it has the potential to have as great an impact on today's audience as the original did for those of us lucky enough to experience it in 1980. Carl Sagan was our guide in the original. I remember learning Sagan's distinctive way of pronouncing his words as I soaked up the beautiful way the series showed our connection to the universe around us and how we discovered that connection through the process of science and the creativity and tenacity of the human spirit. I became good enough at Sagan's pronunciation style that my brother had me read a passage from one of Sagan's books to describe Sagan to his future wife (yes, one of those life skills so important to a teenager).

The one episode where Sagan showed the physical connection to the cosmos at the atomic level was episode 9 "The Lives of the Stars". I remember it well because I show that episode in my astronomy class. Even though the dress fashion is a bit outdated, the information and Sagan's message is timeless. In that episode Sagan talks about how the atoms are created in the stars through nuclear fusion and then scattered out into the universe when stars die, so the atoms can be used to form other stars, planets, and life on those planets, including life advanced enough to be self-aware and aware of where it came from. "We are made of starstuff" and "we are children of the stars" are two famous quotes from Sagan that sum up one of the key messages of the series.

Late March at 8:30 pmMany of today's science teachers grew up on Sagan (well, okay, the middle-aged ones of us anyway) and maybe the guide for the new Cosmos, Neil de Grasse Tyson, will be just as significant for the future scientists in our middle school and high schools today. Of course, the new series is intended for adults too, even those who don't know much about science at all. In fact, the executive director, Ann Druyan, says the series is especially for anyone who never dreamed that they had any interest in the subject matter. I encourage you to check out the new Cosmos series either on Sunday nights or Monday nights (and this is a recommendation from someone who refuses to watch more than three hours of TV a month).

Another piece of astronomy news that has made its way to the popular media is the break up of an asteroid with the exciting name of P/2013 R3. The asteroid was first discovered in mid-September last year in the Catalina and Pan-STARRS sky surveys that are tasked with finding near-Earth objects. The sky surveys find plenty of other asteroids and comets that have no chance of coming close to Earth such as P/2013 R3.

The break up is not the result of a collision since new chunks appeared over an extended time period and were separating from each other much slower than would happen in a collision. Also, the asteroid stays too far away from the Sun for the Sun's heat to melt or vaporise any ices that might be holding pieces of the asteroid together. That leaves an obscure process called the YORP effect (named after the four scientists who theorized about it several years ago: Yarkovsky, O'Keefe, Radzievskii, and Paddack). The YORP effect happens as a result of an asteroid not being perfectly symmetrical and uniform. Some parts of the asteroid are darker and shaped differently than other parts. This will make some parts of the asteroid be better emitters of the asteroid's internal infrared heat energy than others. This slight imbalance of the infrared heat emission can supply a small but constant torque on the asteroid, making it spin faster or slower. In the case of P/2013 R3, the YORP effect seems to have made the asteroid spin itself apart. While astronomers have detected the YORP effect on just a few other asteroids, this is the first known example of an asteroid break-up being caused by it.

In our night sky, Jupiter is now slowly moving forward again among the stars of Gemini (see the second star chart below). For the past few months, Jupiter was moving backward (westward) between the twins of Gemini, almost making it to the string of stars belonging to westernmost twin of the pair, Castor. By the end of May it will be just east of the eastern twin, Pollux. The Full Moon rises tonight below the stars of Leo as the Sun is setting. Now that we're in daylight savings time, the Full Moon will up highest due South at 1 AM still below the stars of Leo (see the first star chart below). The Moon will wash out most of the stars around it but you should be able to still pick out the brightest stars of Leo, Regulus at the end of the Sickle and Denebola at the tip of Leo's tail (at eastern tip of the triangle part of Leo).

At other times of the year when the Moon is not around to point to its location, I find Leo by first looking for the Big Dipper in Ursa Major because it is bright enough to see in even light-polluted skies and also because it is always in the northern sky (usually I have enough information to know which way is north). Instead of following the line of the pointer stars at the end of the bowl of the Big Dipper northward, follow the line "down" or southward below the bowl and look for a backward question mark on the sky as shown in the first star chart below. That is the Sickle part of Leo which corresponds to the head and front of Leo. Regulus is the blue-white bright star at the end of the question mark at the chest of the lion.

Mid-March at 6:30 amTo the left of the Moon, all of the stars of Virgo will be washed out except for bright Spica at the lower left (East) part of the constellation. On the night of March 17/18, the Moon will pass close to Spica on our sky. Nearby is the even brighter orange-red planet Mars. Mars is visible rising in the east with the stars of Virgo by around 9:45 PM and it'll rise earlier on the following nights as a result of the normal four minute/night shift of the stars and its retrograde motion. Mars has been moving backward among the stars of Virgo since the second week of March and will continue so for the next few months. It will drift past Porrima at the lower right (West) part of Virgo in last weeks of May. Already up by midnight will be yellow-white Saturn among the dim stars of Libra. The gibbous Moon will pass be to the left of Saturn the night of March 20/21. Super bright Venus will be visible rising in the East after 5 AM at the western side of Capricornus and Mercury will rise about an hour later between Capricornus and Aquarius, though Mercury will probably be a bit difficult to spot in the pre-dawn twilight. The third star chart below shows the pre-dawn morning view.

The morning of March 20th marks our spring equinox when the Sun crosses the Celestial Equator heading northward. The Celestial Equator is the projection of the Earth's equator onto the sky. The equinox time is when the center of the Sun is exactly on the Celestial Equator, so I can very precisely say that the equinox will happen at 9:57 AM on March 20th, our time. Astronomers like to say that the equinox dates are when we have twelve hours of daylight and twelve hours of night, so the nights are equal to the day and are the same 12 hours over all the Earth ("equal night" = "equi - nox"). However, meteorologists say the equal hours of day and night happen before the Equinox date because they start counting daylight when the very top of the Sun appears on the horizon and the end of daylight is when the very top drops below the horizon, rather than measuring the center-point of the Sun like the astronomers do. Well, okay, I guess that makes more sense but I'm going to stick with my astronomy definition (and remember who's writing this column).

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.

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Nick Strobel
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com

 

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