What's Up - October 2015

What's Up for October. Ten amazing sights in the sky!

Hello and welcome. I'm Jane Houston Jones at NASA's Jet Propulsion Laboratory in Pasadena, California. To celebrate the 100th episode of 'What's Up,' I want to share with you some of my favorite celestial things. Luckily, October is a great month to see them all!

Number 10: As the sun sets, watch its color. The thick atmosphere absorbs most colors of sunlight, but red light is absorbed the least. Rarely, green flashes can be seen just above the sun's edge just as the last sliver of the disk disappears below the horizon.

Number 9: Just after sunset, turn around and face east. You'll soon see a dark shadow move up from the horizon and gradually cover the pinkish sky. This is called the Earth Shadow or the Belt of Venus. Earth itself is blocking the sunlight.

Number 8: Also just after sunset--or before dawn--you may see rays of sunlight spread like a fan. These are crepuscular rays, formed when sunlight streams through gaps in the clouds or mountains.

Number 7: The bright flowing lights of the aurora borealis, or northern lights, are the result of collisions between gaseous particles in Earth's atmosphere and charged particles released from the sun. The different colors you can see are due to the type of gas being struck by particles of the solar wind. Yellow-green aurorae and red aurorae are produced by oxygen molecules. And purple or blue is from nitrogen. You can find out when and where to expect aurorae at the Space Weather Prediction Center.

Number 6: The Andromeda Galaxy is one of the few galaxies you can actually see with your naked eye. In October, look nearly overhead after sunset. The galaxy is more than twice the apparent width of the moon.

Number 5: Mid-October are excellent nights to view the features on the moon, such as the Sea of Tranquility and the site of the 1969 Apollo 11 landing.

Number 4: This month the European Space Agency's Rosetta mission target, Comet 67P Churyumov-Gerasimenko, is still bright enough for experienced astronomers to pick out in a dark sky. On October 9, you may be able to spot it in the east near the crescent moon and Venus.

Number 3: There are meteor showers galore this month. On the 9th: the faint, slow-moving Draconids. On the 10th: the slow, super-bright Taurids. And on the 21st: the swift and bright Orionids from the dust of Comet Halley.

Number 2: On October 28, you'll find a tight grouping of Jupiter, Venus and Mars in the eastern sky before sunrise.

And number 1: I'll end this list with my very favorite astronomical sight, the Zodiacal light. It's a faint triangular glow seen from a dark sky after sunset or before sunrise. What we're seeing is sunlight reflecting off dust grains that circle the sun in the inner solar system. These dust grains travel in the same plane--called the ecliptic--as the moon and planets as they journey across our sky.

You can find NASA tools and resources for armchair astronomy and solar system and deep sky observing at solarsystem.nasa.gov/StarToolBox.

And you can learn about all of NASA's missions at www.nasa.gov.

That's all for this month. I'm Jane Houston Jones.