CELESTIAL LIGHTS
February’s Celestial Lights 
By Phyllis Burton Pitluga

When we think of ourselves as nature lovers, we need to remember that half of nature is overhead. Early cultures understood this and even made offerings to celestial gods, in the hope they’d guarantee nourishment and fertility to life on the Earth’s surface. For us to recognize some of these “gods,” we need to appreciate the celestial choreography going on above us each night.

Our biggest and brightest “landmark” in the sky is our Moon. It’s the closest celestial body in the heavens and thus moves noticeably, from night to night, across the sky. This motion is most visible when you schedule your observation for the same time each night. The Moon moves continuously eastward as it orbits around the Earth each month. The daily motion averages 13 degrees—a little more than the width of your extended fist against the sky. During each month, the Moon passes by different planets and bright stars as it orbits the Earth. Each month, the position of these planets and stars change as the Earth and planets move—the greater the distance from the Earth, the more gradual the observed changes.

To get started, go outside in the evening about seven o’clock and look for the Moon. From night to night, notice the Moon’s gradual changes in shape and position. On January 29, the Moon was “new”—the side facing Earth was in complete darkness. By the next night, a slender crescent of sunlight shines on the Moon. Each night, as the Moon orbits a bit further around Earth, more and more sunlight reflects off the Moon. As the Moon continues its orbit, it passes by several bright planets and stars. The third planet from the Sun is our own Earth, which we never see in the night sky, of course, because we’re standing on it.

What you’ll see and when
  • Sunday, February 5: First-quarter Moon (looks like half a Moon) passes above Mars (4th planet)
  • Monday, February 6: Moon passes above the Pleiades star cluster
  • Saturday, February 11: Moon passing above Saturn (6th planet)
  • Sunday, February 12: Full Moon rises at sunset, so for the next two week, allow an additional hour each night for the Moon to rise—better yet, follow the sequence in the dawn sky before sunrise
  • Friday, February 17: Moon passes just above the bright star Spica
  • Monday, February 20: Moon passes below Jupiter (5th planet)
  • Tuesday, February 21: Last-quarter Moon passes just below the star Antares
  • Friday, February 24: Moon passes below Venus (2nd planet)
  • Saturday, February 25: Moon passes just below the asteroid Ceres (requires telescope)
  • Sunday, February 26: Moon passes below Neptune (8th planet; requires telescope)

Stardust update

The Stardust space capsule safely hurtled through Earth’s atmosphere just after four o’clock in the morning on January 15—creating a brilliant fireball, just like a meteor. The precious cargo of sampled material from a comet tail is now being analyzed by scientists in the Stardust Clean Room at the Johnson Space Center in Houston, Texas. Take a peek at their web-cam to see the progress of the analyses: www.nasa.gov/externalflash/stardust_front/stardust_webcam

Spica is the brightest star of the constellation Virgo. It is similar to our star—the Sun—but much hotter. Spica has two companion stars, making it a triple-star system. Our Sun is a single star accompanied by planets, moons, asteroids and comets.

Antares is the brightest star in the constellation of Scorpious. It is a “red giant” star, running out of its central nuclear energy but still drawing in surrounding plasma causing it to brighten, then dim, irregularly.

Ceres is this solar system’s biggest asteroid. It’s about 600 miles in diameter—compared to Earth at 8,000 miles and our Moon at about 2,000 miles. Asteroids are small rocky worlds. More than a million asteroids orbit in a belt between Mars and Jupiter. Jupiter’s strong gravitational field probably prevented the asteroids from drawing together into a planet as our solar system was forming 4.6 billion years ago.

Phyllis Burton Pitluga, Astronomer Emerita of the Adler Planetarium and Astronomy Museum, Chicago, is now a San Miguel resident.

You can reach her at ppitluga@adlerplanetarium.org