Astronomy Picture Of the Day (APOD)Comet Machholz Approaches the Sun
Why is Comet Maccholz so depleted of carbon-containing chemicals? Comet 96P/Machholz's original fame derives from its getting closer to the Sun than any other short period comet -- half as close as Mercury -- and doing so every five years.
A Happy Sky over Los Angeles
Sometimes, the sky may seem to smile over much of planet Earth. On this day in 2008, visible the world over, was an unusual superposition of our Moon and the planets Venus and Jupiter.
A Colourful Moon
The Moon is normally seen in subtle shades of grey. But small, measurable color differences have been greatly exaggerated in this mosaic of high-resolution images captured near the Moon's full phase, to construct a multicolored, central moonscape.
Williamina Fleming s Triangular Wisp
Chaotic in appearance, these tangled filaments of shocked, glowing gas are spread across planet Earth's sky toward the constellation of Cygnus as part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star.
NGC 1055 Close up
Big, beautiful spiral galaxy NGC 1055 is a dominant member of a small galaxy group a mere 60 million light-years away toward the aquatically intimidating constellation Cetus. Seen edge-on, the island universe spans over 100,000 light-years, a little larger than our own Milky Way.
NGC 2261: Hubble s Variable Nebula
What causes Hubble's Variable Nebula to vary? The unusual nebula featured here changes its appearance noticeably in just a few weeks. Discovered over 200 years ago and subsequently cataloged as NGC 2661, the remarkable nebula is named for Edwin Hubble, who studied it early last century.
The Prague Astronomical Clock
In the center of Prague there's a clock the size of a building. During the day, crowds gather to watch the show when it chimes in a new hour. The Prague Astronomical Clock...
A Dust Jet from the Surface of Comet 67P
Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. Last year, though, ESA's Rosetta spacecraft not only imaged a jet emerging from Comet 67P/Churyumov-Gerasimenko, but flew right through it.
A Year of Full Moons
Do all full moons look the same? No. To see the slight differences, consider this grid of twelve full moons. From upper left to lower right, the images represent every lunation from 2016 November through 2017 October, as imaged from Pakistan.
Hubble s Messier 5
"Beautiful Nebula discovered between the Balance [Libra] & the Serpent [Serpens] ..." begins the description of the 5th entry in 18th century astronomer Charles Messier's famous catalog of nebulae and star clusters. Though it appeared...