COBE Dipole: Speeding Through the Universe
5.02.1996

Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of the Milky Way Galaxy. The Milky Way Galaxy orbits in the Local Group. The Local Group falls toward the Virgo Cluster of Galaxies.

Colorful Clouds Near Rho Ophiuchi
6.07.2015

Why is the sky near Antares and Rho Ophiuchi so colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark.

Announcing Comet Catalina
18.08.2015

Will Comet Catalina become visible to the unaided eye? Given the unpredictability of comets, no one can say for sure, but it seems like a good bet. The comet was discovered in 2013 by observations of the Catalina Sky Survey.

McNaught Now Brightest Comet in Decades
9.01.2007

The brightest comet in decades is unexpectedly now visible. The most optimistic predictions have Comet McNaught (C/2006 P1) shortly becoming one of the brightest comets of the past century. For the next few days...

Dueling Bands in the Night
27.02.2018

What are these two bands in the sky? The more commonly seen band is the one on the right and is the central band of our Milky Way galaxy. Our Sun orbits...

Jet Approaching a Crescent Moon
5.06.2007

No natural clouds appear in this picture. On the left, an airplane cruises through the atmosphere leaving a contrail in its wake. The contrail would normally appear white, but the large volume of air toward the setting Sun preferentially knocks away blue light, giving the reflected trail a bright orange hue.

Mars Red and Spica Blue
2.04.2014

A bright pair of sky objects will be visible together during the next few months. Mars will shine brightly in its familiar rusty hue as it reaches its brightest of 2014 next week.

Winter Hexagon over Manla Reservoir
23.01.2017

If you can find Orion, you might be able to find the Winter Hexagon. The Winter Hexagon involves some of the brightest stars visible, together forming a large and easily found pattern in the winter sky of Earth's northern hemisphere.

Lyrid Meteor Streak
23.04.2020

Earth's annual Lyrid Meteor Shower peaked before dawn yesterday, as our fair planet plowed through debris from the tail of long-period comet Thatcher. In crisp, clear and moonless predawn skies over Brown County...

APOD: 2024 August 11 Б Animation: Perseid Meteor Shower
11.08.2024

Where do Perseid meteors come from? Mostly small bits of stony grit, Perseid meteoroids were once expelled from Comet Swift-Tuttle and continue to follow this comet's orbit as they slowly disperse. The featured animation depicts the entire meteoroid stream as it orbits our Sun.