David L. Richards
I hope many of you had the opportunity to see Comet Pan-STARRS.
I never did spot it, but we may yet have another chance this year to see a comet. Some astronomers are predicting Comet ISON to be “the comet of the century,” while others say it is not brightening as expected. We will find out later this year.
Saturn will rise in the east at the beginning of April around 10 p.m., while Jupiter will set in the west three hours later. On April 26, Saturn and the nearly full moon will be only 3 degrees apart. Saturn’s ring system is tilted about 18 degrees from our line of sight, the most open they have been in seven years. In 2017 the rings will achieve their maximum tilt of 27 degrees.
On April 14, Jupiter and a sliver of the waxing crescent moon will be separated by only 4 degrees. Venus will not emerge from the sun’s glare until late in April, and Mars not until late June.
In the early morning hours of April 22 the Lyrid meteor shower will peak, with a maximum of about 10 meteors an hour. Unfortunately, the waxing gibbous moon will limit observations to only the brightest meteors.
A partial lunar eclipse occurs on April 25, but you will have to visit the Eastern Hemisphere to observe it. Not until next April will we see a total lunar eclipse in Ohio.
Q: What causes comets? Where do they come from? — T.H., Canton
A: The current theory is that comets originate in an enormous cloud of ice and dust that surrounds the solar system, called the Oort Cloud. This spherical cloud extends almost halfway to the nearest star, Proxima Centauri. Passing stars and the outer gas giant planets disturb the elliptical orbits of comets in the cloud, sending them toward the sun.
Many comets orbit the sun with a predictable period, from three years to hundreds of thousands of years. Some comets originate in the Kuiper Belt, an area similar to the asteroid belt, and these are usually the short-period comets, some of which have orbits only out to Jupiter.
As the comet approaches the sun, the ices melt, and leave a debris trail, or tail. If this trail crosses Earth’s orbit, we may experience a meteor shower. Many meteor showers can be traced back to the debris trails of known comets.
The Hoover-Price Planetarium will begin presenting Citizen Science on April 27. Astronomy is one of the sciences where ordinary citizens — sometimes using extraordinary equipment — may make outstanding contributions to the scientific community. We’ll look at how you can take part in this fascinating venture, just using your eyes.
Shows are at 1 p.m. Saturdays and 2 p.m. Sundays. The Planetarium is included with admission to the McKinley Presidential Library & Museum. Call 330-455-7043 for more information.
David L. Richards is director of the Hoover-Price Planetarium at the McKinley Presidential Library and Museum, 800 McKinley Monument Drive NW, Canton, OH 44708, www.mckinleymuseum.org. He can be reached at 330-455-7043 or email firstname.lastname@example.org.