Category Archives: Science

Behold: globular star cluster NGC 6752, 13,000 light-years away toward the southern constellation Pavo (the Peacock), roaming the halo of the Milky Way. To wit:

Over 10 billion years old, NGC 6752 follows clusters Omega Centauri and 47 Tucanae as the third brightest globular in planet Earth’s night sky. It holds over 100 thousand stars in a sphere about 100 light-years in diameter. Telescopic explorations of the NGC 6752 have found that a remarkable fraction of the stars near the cluster’s core, are multiple star systems. They also reveal the presence of blue straggle stars, stars which appear to be too young and massive to exist in a cluster whose stars are all expected to be at least twice as old as the Sun. The blue stragglers are thought to be formed by star mergers and collisions in the dense stellar environment at the cluster’s core. This sharp color composite also features the cluster’s ancient red giant stars in yellowish hues. (Note: The bright, spiky blue star at 11 o’clock from the cluster center is a foreground star along the line-of-sight to NGC 6752).

(Image: Jose Joaquin Perez)

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Behold: the Hyades or Caldwell 41 – the closest star cluster to our own sun. To wit:

The Hyades open cluster is bright enough to have been remarked on even thousands of years ago, yet is not as bright or compact as the nearby Pleiades (M45) star cluster. Pictured here is a particularly deep image of the Hyades which has brings out vivid star colours and faint coincidental nebulas. The brightest star in the field is yellow Aldebaran, the eye of the bull toward the constellation of Taurus. Aldebaran, at 65 light-years away, is now known to be unrelated to the Hyades cluster, which lies 153 light-years away. The central Hyades stars are spread out over about 15 light-years. Formed about 625 million years ago, the Hyades likely shares a common origin with the Beehive cluster (M44), a naked-eye open star cluster toward the constellation of Cancer, based on M44‘s motion through space and remarkably similar age.

(Image: Jose Mtanous)

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Behold: spiral galaxy NGC 247, 11 million light years from us toward the southern constellation Cetus, smaller than the Milky Way and strangely redolent of something even smaller. To wit:

The pronounced void on one side of the galaxy’s disk recalls for some its popular name, the Needle’s Eye galaxy. Many background galaxies are visible in this sharp galaxy portrait, including the remarkable string of four galaxies just below and left of NGC 247 known as Burbidge’s Chain. Burbidge’s Chain galaxies are about 300 million light-years distant. NGC 247 itself is part of the Sculptor Group of galaxies along with the shiny spiral NGC 253.

(Image: Acquisition – Eric Benson, Processing – Dietmar Hager)

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There are more known volcanoes on Venus that there are on Earth but, until now, it’s not been clear which ones, if any, are active. To wit:

Evidence bolstering very recent volcanism on Venus has recently been uncovered, though, right here on Earth. Lab results showed that images of surface lava would become dim in the infrared in only months in the dense Venusian atmosphere, a dimming not seen in ESA’s Venus Express images. Venus Express entered orbit around Venus in 2006 and remained in contact with Earth until 2014. Therefore, the infrared glow (shown in false-color red) recorded by Venus Express for Idunn Mons and featured here on a NASA Magellan image indicates that this volcano erupted very recently — and is still active today. Understanding the volcanics of Venus might lead to insight about the volcanics on Earth, as well as elsewhere in our Solar System.

(Image: NASA, JPL-Caltech, ESA, Venus Express: VIRTIS, USRA, LPI)

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Another gorgeous shot of the ‘Mother of Pearl’ or nacreous cloud formations which occurred late last year over Sweden, in this case, on New Year’s Eve in the skies above Ostersund. To wit:

A relatively rare phenomenon in clouds known as iridescence can bring up unusual colours vividly or even a whole spectrum of colours simultaneously. These polar stratospheric clouds clouds (…) are formed of small water droplets of nearly uniform size. When the Sun is in the right position and, typically, hidden from direct view, these thin clouds can be seen significantly diffracting sunlight in a nearly coherent manner, with different colors being deflected by different amounts. Therefore, different colours will come to the observer from slightly different directions. Many clouds start with uniform regions that could show iridescence but quickly become too thick, too mixed, or too angularly far from the Sun to exhibit striking colours. 

(Image: Goran Strand)

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Behold: cosmic dust clouds and young, energetic stars on the northern border of Corona Australis. To wit:

The dust clouds effectively block light from more distant background stars in the Milky Way. But the striking complex of reflection nebulae cataloged as NGC 6726, 6727, and IC 4812 produce a characteristic blue color as light from the region’s young hot stars is reflected by the cosmic dust. The dust also obscures from view stars still in the process of formation. At the left, smaller yellowish nebula NGC 6729 bends around young variable star R Coronae Australis. Just below it, glowing arcs and loops shocked by outflows from embedded newborn stars are identified as Herbig-Haro objects. On the sky this field of view spans about 1 degree. That corresponds to almost 9 light-years at the estimated distance of the nearby star forming region.

(Image: CHART32 Team, Processing – Johannes Schedler)

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Behold: NGC 602 – a cluster of stars 200,000 light years away near the outskirts of the Small Magellanic Cloud, captured in a stunning image by the Hubble Space Telescope. To wit:

…augmented by images in the X-ray by Chandra, and in the infrared by Spitzer. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602’s massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster’s center. At the estimated distance of the Small Magellanic Cloud, the Picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in this sharp multi-colored view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.

(Image: X-ray: Chandra: NASA/CXC/Univ.Potsdam/L.Oskinova et al; Optical: Hubble: NASA/STScI; Infrared: Spitzer: NASA/JPL-Caltech)

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Behold: vivid iridescent nacreous or ‘mother of pearl’ clouds over Tandalen in Sweden late last week. To wit:

 …they are rare. This northern winter season they have been making unforgettable appearances at high latitudes, though. A type of polar stratospheric cloud, they form when unusually cold temperatures in the usually cloudless lower stratosphere form ice crystals. Still sunlit at altitudes of around 15 to 25 kilometers the clouds can diffract sunlight after sunset and before the dawn.

Image: P-M Hedén (Clear Skies, TWAN)

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Behold: the face-on spiral of M33, aka the Pinwheel Galaxy, aka The Triangulum Galaxy. To wit:

M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other’s grand spiral star systems. As for the view from planet Earth, this sharp image shows off M33’s blue star clusters and pinkish star forming regions along the galaxy’s loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 7 o’clock position from the galaxy center. Like M31, M33’s population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.

(Image: Rui Liao)

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