Badger: Pluto’s pictures reveal two layers of haze

The remarkable findings of the New Horizons spacecraft continue to slowly flow in on the backlogged data feed strangled by extreme distance and power limitations. One striking image was taken as New Horizons looked back with its Long Range Reconnaissance Imager (LORRI) seven hours after closest approach.

Weak sunlight skimming the atmosphere shows hazes as high as 80 miles above Pluto’s icy surface. A purely gaseous atmosphere would be transparent. Two distinct layers of haze seem to be present, one about 50 miles up and the second lower at an altitude of about 30 miles.

Pluto does not support a “normal” atmosphere. Its temperature of -390° Fahrenheit turns nitrogen into ice. Indeed the surface of Pluto seems to have regions where nitrogen ice is flowing like a glacier.

Even so, some molecules in the ice “sublimate” escape directly from the solid form back into a gas. So there is still a small remnant of an atmosphere, but its pressure is about 1/100-thousandth that of Earth’s atmosphere. Additional molecules present in the atmosphere come from methane, the simplest hydrocarbon.

If it were just these thin gasses, Pluto’s atmosphere would be invisible. But something is changing the simple gasses into tiny snowflakes.

Scientific models explain how the hazes form when ultraviolet sunlight breaks up methane gas. Once broken up, the methane fragments recombine with other methane molecules to build up more complex hydrocarbon gases, such as ethylene and acetylene, which also were discovered in Pluto’s atmosphere by New Horizons. As these larger, heavier hydrocarbons fall to the lower, colder parts of the atmosphere, they condense into ice particles that scatter sunlight.

Ultraviolent sunlight powers further chemical reactions, which convert hazes into tholins, the dark hydrocarbons that color most of Pluto’s surface, except the bright heart-shaped area unofficially called Tombaugh Regio.

At the planetarium

You can check http://www.calendarwiz.com/planetarium for the latest planetarium show times and titles plus descriptions of the shows.

A visit to the planetarium should always include a free look through the 24-inch telescope. Venus and Jupiter are visible before about 9:30 p.m. and Saturn is on view until closing.

You may also call the planetarium box office at 321-433-7373 to hear the latest schedule information and prices.

Mr. Badger is Project Coordinator at the Eastern Florida State College Planetarium in Cocoa. Send questions, suggestions, or comments to badgerb@easternflorida.edu

At the planetarium

Friday

7 p.m. The Planets

8:15 Solar Max (IMAX)

9 U2 Laser Experience

Saturday

7 p.m.Mars Quest

8:15 Solar Max (IMAX)

9 Pink Floyd " Dark Side of the Moon" Laser Experience

Wednesday

2 p.m. Amazing Universe

3:15 Whales (IMAX)