Fabulous sunsets after a thunderstorm?

Some of the important factors in a photo-worthy red-orange sunset after a storm include timing, cloud patterns, the scattering of sunlight, and air quality in the lower atmosphere, according to the Storm Prediction Center of the National Weather Service and the National Oceanic and Atmospheric Administration, USA.

Most thunderstorms occur in the late afternoon or the evening, close to sunset, when radiant heating and atmospheric instability have reached their peaks. In the aftermath of such a storm, mid-level and high clouds may be left behind, especially cirrus and altocumulus clouds that are ideal as a canvas for painting by the sun’s last rays.

Water-filled clouds in the lower atmosphere will have been depleted by the storm. Those last rays are mostly red or orange because the longer path that light takes through the atmosphere as the sun’s angle becomes ever lower means that the wavelengths of other colours have been scattered away.

Contrary to popular belief, clean air scrubbed by a storm lets more red rays reach the viewer than dirty air would. Dust and smog at low levels would scatter the light too much for an ideal sunset.

How sunflowers follow the sun, day after day

At dawn, whole fields of sunflowers stand at attention, all facing east, and begin their romance with the rising sun. Young flowers follow its light through the day, looking up, then over and westward, catching one final glance as the sun disappears over the horizon.

It’s not love. It’s heliotropism, and how sunflowers do it has been a mystery. But researchers have discovered that the sunflower’s internal clock and ability to detect light work together, turning on genes related to growth at just the right time to allow the stems to bend with the arc of the sun. The stems of fully grown plants do not bend, and the flowers always face east — apparently warming up early to attract pollinators, the researchers concluded.

Joanna Klein

Biggest salamanders of North America

Take a two-foot-long muscle with a skeleton and coat it in multiple layers of snot. Now squish the muscle down so it’s flat. Add four short legs, 18 toes, a big, wide mouth and beady eyes. Forget about eyelids. Stretch skin along the slimy muscle and wrinkle it on the sides. This is how it will breathe. Now stick Frankenphibian under a big rock in a stream and leave it alone. You’ve just made an adult eastern hellbender, the biggest salamander in North America.

Eastern hellbenders once thrived in waters along the Appalachians, from New York to Georgia and as far west as Missouri. But the population has been in a long decline. Sediment from farmland and developments fills in gaps between river stones, some experts theorise, displacing larvae from their homes.

This month, 255 of these strange creatures, raised to young adults from eggs, will be set free in Ohio by the Columbus Zoo and Aquarium and its partners. It’s a lot of attention for an amphibian with an unflattering nickname: the snot otter.
Joanna Klein