APOD: 2023 February 12 Б Mammatus Clouds over Nebraska
12.02.2023

When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms.

It s Raining on Titan
1.04.2011

It's been raining on Titan. In fact, it's likely been raining methane on Titan and that's not an April Fools' joke. The almost familiar scene depicted in this artist's vision of the surface of Saturn's largest moon looks across an eroding landscape into a stormy sky.

When Venus Rises with the Sun
8.06.2012

This dramatic telephoto view across the Black Sea on June 6 finds Venus rising with the Sun, the planet in silhouette against a ruddy and ragged solar disk. Of course, the reddened light...

The Winter Shower
26.12.2014

Known in the north as a winter meteor shower, the 2014 Geminids rain down on this rugged, frozen landscape. The scene was recorded from the summit of Mt. Changbai along China's northeastern border with North Korea as a composite of digital frames capturing bright meteors near the shower's peak.

Light Pillars over Whitefish Bay
24.10.2018

What's happening in the sky? Unusual lights appeared last week to hover above Whitefish Bay on the eastern edge of Lake Superior between the USA and Canada. Unsure of the cause, the Michigan-based...

Geysers on Triton
5.08.1995

In August of 1989 NASA's Voyager 2 spacecraft passed by Neptune, the most distant of the solar system's gas giant planets. Its encounter with Neptune climaxed with its closest approach to Neptune's largest moon Triton.

White Dwarfs Cool
10.09.1995

The circled stars in the above picture are from a class that is hard to see in the cosmos: white dwarfs. The entire photo covers a small region near the center of a globular cluster known as M4. Researchers using the Hubble Space Telescope discovered a large concentration of white dwarfs in M4.

Layer Cake Sunset
20.01.2017

On January 18 a tantalizing sunset was captured in this snapshot. Seemingly sliced into many horizontal layers the Sun shimmered moments before it touched the horizon, setting over the Pacific Ocean as seen from the mountaintop Las Campanas Observatory in Chile.

Star Trails at 19 000 Feet
2.12.2006

In myth, Atlas holds up the heavens, but in this stunning view a mountain appears to serve as the southern night sky pivots around a snowy peak. Recorded during a climbing expedition...

Mammatus Clouds Over Olympic Valley
20.02.2011

What's happened to these clouds? Normal cloud bottoms are flat because moist warm air that rises and cools will condense into water droplets at a very specific temperature, which usually corresponds to a very specific height. After water droplets form that air becomes an opaque cloud.