atmospheric effects Archives

June 27, 2020June 27, 2020 by Matt Williams

A Simulation of Sunsets on Other Worlds: From Venus to Titan

When we think of exploring other planets and celestial bodies, we tend to focus on the big questions. How would astronauts live there when they’re not working? What kind of strategies and technology would be needed for people to be there long term? How might the gravity, environment, and radiation effect humans who choose to make places like the Moon, Mars, and other bodies place their home? We tend to overlook the simple stuff…

For example, what will it be like to look up at the sky? How will Earth, the stars, and any moon in orbit appear? And how will it look to watch the sun go down? These are things we take for granted here on Earth and don’t really ponder much. But thanks to NASA, we now have a tool that simulates what sunsets would look like from other bodies in the Solar System – from the hellish surface of Venus to the dense atmosphere of Uranus.

June 27, 2014December 23, 2015 by Nancy Atkinson

What are Those Colorful, Crazy Clouds in the Sky??

Ethereal and stunning sundog-like forms in the clouds over Oxford, England on June 25, 2014. Credit and copyright: Nathanial Burton-Bradford.

My Twitter feed exploded on June 25 with reports of colorful, crazy-looking clouds, sundogs, Sun halos and more. The above image from Nathanial Burton-Bradford is just an example of the type of atmospheric effect called a circumhorizontal arc. These are sometimes referred to as “fire rainbows” but of course are not rainbows, and fire plays no role.

This is an optical phenomenon from sunlight hitting ice crystals in high cirrus clouds. It is actually a rather rare occurrence, but it happens most often during the daytime in summer when the Sun is high in the sky. This creates a rainbow-type effect directly in the ice crystal-filled clouds.

See more examples below.

Wispy clouds and a circumhorizontal arc over Italy. Credit and copyright: Elisabetta Bonora.

Circumhorizontal Arc over the UK on June 25, 2014. Credit and copyright: Sculptor Lil on Flickr.

You can find out more about circumhorizontal arcs from this article from Amusing Planet.

November 6, 2013December 23, 2015 by Nancy Atkinson

Spectacular Halo Around the Sun Seen in Africa

A solar halo seen over Klerksdorp, South Africa. Credit: Daniël Engelbrecht

Fresh off seeing a solar eclipse on Sunday, people across the southern parts of Africa witnessed another solar spectacle today, a sun halo. “It was so beautiful, everyone was taking pictures and sharing them on Facebook,” said Daniël Engelbrecht from Klerksdorp, South Africa, sending in his picture to Universe Today via email.

These halos are quite the sight to see, but unlike an eclipse, they can’t be predicted. Conditions in the atmosphere have to be just right, with moisture or ice crystals creating a “rainbow” effect around the Sun. Sometimes the halos surround the Sun completely, other times, they appear as arcs around the Sun creating what is known as sundogs. Basically, sunlight is reflecting off moisture in the atmosphere.

Ice crystals in Earth’s atmosphere can also cause rings around the Moon, and moondogs(as well as sundogs) and even Venus pillars. News reports indicate sun halos were seen just a few days ago in Africa as well, on Nov. 1, 2013.

A few other people sent in images from their phones, too of today’s sun halo: