Interstellar dust clouds make the dark skies blue

Interstellar dust clouds make the dark skies blue

[CLICK ON IMAGE FOR HIGH RESOLUTION.] This lovely blue cosmic cloud begins the van den Bergh Catalog (vdB) of stars surrounded by reflection nebulae. Interstellar dust clouds reflecting the light of the nearby stars, the nebulae usually appear blue because scattering by the dust grains is more effective at shorter (bluer) wavelengths. The same type […]

Orion’s Horsehead Nebula, 1,500 years ago

Orion’s Horsehead Nebula, 1,500 years ago

One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the […]

Stars of the Trapezium light up the spectacular Orion Nebula

Stars of the Trapezium light up the spectacular Orion Nebula

Near the center of this sharp cosmic portrait, at the heart of the Orion Nebula, are four hot, massive stars known as the Trapezium. Gathered within a region about 1.5 light-years in radius, they dominate the core of the dense Orion Nebula Star Cluster. Ultraviolet ionizing radiation from the Trapezium stars, mostly from the brightest […]

Death of a star give rise to Helix Nebula

Death of a star give rise to Helix Nebula

A mere seven hundred light years from Earth, in the constellation Aquarius, a sun-like star is dying. Its last few thousand years have produced the Helix Nebula (NGC 7293), a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. A total of 58 hours of exposure time […]

Odd couple in the Virgo galaxy cluster

Odd couple in the Virgo galaxy cluster

[Click on image for high resolution] Giant elliptical galaxy M60 and spiral galaxy NGC 4647 do look like an odd couple in this sharp cosmic portrait from the Hubble Space Telescope. But they are found in a region of space where galaxies tend to gather, on the eastern side of the nearby Virgo Galaxy Cluster. […]

The always magnificent Pleiades

The always magnificent Pleiades

Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters. The Pleiades contains over 3000 stars, is about 400 light years away, […]

The red supergiant Antares and its spectacular field of view

The red supergiant Antares and its spectacular field of view

[CLICK ON IMAGE FOR HIGH RESOLUTION] Why is the sky near Antares and Rho Ophiuchi so colorful? … 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. Antares, a red […]