Circling the Sun
13.01.2024

Earth's orbit around the Sun is not a circle, it's an ellipse. The point along its elliptical orbit where our fair planet is closest to the Sun is called perihelion. This year...

M86 in the Central Virgo Cluster
14.08.2018

Is there a bridge of gas connecting these two great galaxies? Quite possibly, but it is hard to be sure. M86 on the upper left is a giant elliptical galaxy near the center of the nearby Virgo Cluster of galaxies.

APOD: 2024 July 7 Б Iridescent Clouds over Sweden
7.07.2024

Why are these clouds multi-colored? A relatively rare phenomenon in clouds known as iridescence can bring up unusual colors vividly -- or even a whole spectrum of colors simultaneously. These polar stratospheric clouds also, known as nacreous and mother-of-pearl clouds, are formed of small water droplets of nearly uniform size.

Iridescent Clouds over Sweden
15.01.2020

Why would these clouds multi-colored? A relatively rare phenomenon in clouds known as iridescence can bring up unusual colors vividly or even a whole spectrum of colors simultaneously. These polar stratospheric clouds clouds, also known as nacreous and mother-of-pearl clouds, are formed of small water droplets of nearly uniform size.

Moonrise Over Seattle
30.01.2002

Is the Moon larger when near the horizon? No -- as shown above, the Moon appears to be very nearly the same size no matter its location on the sky. Oddly, the cause or causes for the common Moon Illusion are still being debated.

Moonrise Over Seattle
11.10.2003

Is the Moon larger when near the horizon? No -- as shown above, the Moon appears to be very nearly the same size no matter its location on the sky. Oddly, the cause or causes for the common Moon Illusion are still being debated.

Moonrise Over Turkey
16.06.2009

Is the Moon larger when near the horizon? No -- as shown above, the Moon appears to be very nearly the same size no matter its location on the sky. Oddly, the cause or causes for the common Moon Illusion are still being debated.