Starship Asterisk*

Image Credit: ESO/Petr Horálek

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This Picture of the Week appears to show a lone antenna gazing at the sky — but in reality this antenna is far from lonely. It is part of the Atacama Large Millimeter/submillimeter Array (ALMA), a telescope that comprises 66 high-precision antennas spread out across the Chajnantor plateau, located high up in the Chilean Andes. In this image we are treated to a spectacularly multi-coloured view of the sky above ALMA: green airglow hovers above the horizon, the Large Magellanic Cloud peeks out from behind the antenna, and the magnificent sprawl of the Milky Way stretches out overhead.

These antennas are optimised to collect light at millimetre wavelengths, between infrared and radio waves, giving ALMA a view of the Universe that is very different to our own. Human eyes have evolved to see visible light while ALMA views the cosmos at longer wavelengths, picking up light from some of the coldest objects in the Universe — dense star-forming clouds, discs of debris around newborn stars, distant galaxies, and more. ALMA can probe these objects with unprecedented sensitivity and resolution. The array has observed Einstein Rings, imaged protoplanetary discs, and detected complex organic molecules within such discs, suggesting that the Solar System may not be unique in its ability to foster life.

Image Credit: ESA/Hubble & NASA, R. Massey

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This detailed image features Abell 3827, a galaxy cluster that offers a wealth of exciting possibilities for study. It was observed by Hubble in order to study dark matter, which is one of the greatest puzzles cosmologists face today. The science team used Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) to complete their observations. The two cameras have different specifications and can observe different parts of the electromagnetic spectrum, so using them both allowed the astronomers to collect more complete information. Abell 3827 has also been observed previously by Hubble, because of the interesting gravitational lens at its core.

Looking at this cluster of hundreds of galaxies, it is amazing to recall that until less than 100 years ago, many astronomers believed that the Milky Way was the only galaxy in the Universe. The possibility of other galaxies had been debated previously, but the matter was not truly settled until Edwin Hubble confirmed that the Great Andromeda Nebula was in fact far too distant to be part of the Milky Way. The Great Andromeda Nebula became the Andromeda Galaxy, and astronomers recognised that our Universe was much, much bigger than humanity had imagined. We can only imagine how Edwin Hubble — after whom the Hubble Space Telescope was named — would have felt if he’d seen this spectacular image of Abell 3827.

Credit: ESO/VLT/FORS2

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This week’s picture of the week features DG121, an HII region — a cloud of ionised hydrogen — located in the constellation of Puppis (the Stern).

HII regions, a type of emission nebulae, are created when young, massive stars release enough ultraviolet energy to ionise the surrounding gas clouds. These regions tend to have irregular structures and lack sharp boundaries, giving them their hazy, yet photogenic, appearance. The brightest star in the DG121 region, seen near the centre in this picture, is HD 60068.

This spectacular image was taken with the FORS 2 (FOcal Reducer and low dispersion Spectrograph 2) instrument on ESO’s Very Large Telescope (VLT) in the Chilean Atacama Desert. This instrument has been described by astronomers as "the Swiss army knife of instruments at Paranal", because of its ability to study many different astronomical objects in many different ways.

Image Credit: ESA/Hubble, R. Sahai

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This Picture of the Week showcases the emission nebula NGC 2313. The bright star V565 — surrounded by four prominent diffraction spikes — illuminates a silvery, fan-shaped veil of gas and dust, while the right half of this image is obscured by a dense cloud of dust. Nebulae with similar shapes — a star accompanied by a bright fan of gas — were once referred to as cometary nebulae, though the name is no longer used.

The language that astronomers use changes as we become better acquainted with the Universe, and astronomical history is littered with now-obsolete phrases to describe objects in the night sky, such as “spiral nebulae” for spiral galaxies or “inferior planets” for Mercury and Venus.

bystander wrote: ↑Mon May 10, 2021 1:50 pm Purple Haze
ESO Picture of the Week | 2021 May 10

Credit: ESO/VLT/FORS2

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This week’s picture of the week features DG121, an HII region — a cloud of ionised hydrogen — located in the constellation of Puppis (the Stern).

HII regions, a type of emission nebulae, are created when young, massive stars release enough ultraviolet energy to ionise the surrounding gas clouds. These regions tend to have irregular structures and lack sharp boundaries, giving them their hazy, yet photogenic, appearance. The brightest star in the DG121 region, seen near the centre in this picture, is HD 60068.

This spectacular image was taken with the FORS 2 (FOcal Reducer and low dispersion Spectrograph 2) instrument on ESO’s Very Large Telescope (VLT) in the Chilean Atacama Desert. This instrument has been described by astronomers as "the Swiss army knife of instruments at Paranal", because of its ability to study many different astronomical objects in many different ways.

bystander wrote: ↑Mon May 10, 2021 1:59 pm Cosmic Silver Lining
ESA Hubble Picture of the Week | 2021 May 10

Image Credit: ESA/Hubble, R. Sahai

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This Picture of the Week showcases the emission nebula NGC 2313. The bright star V565 — surrounded by four prominent diffraction spikes — illuminates a silvery, fan-shaped veil of gas and dust, while the right half of this image is obscured by a dense cloud of dust. Nebulae with similar shapes — a star accompanied by a bright fan of gas — were once referred to as cometary nebulae, though the name is no longer used.

The language that astronomers use changes as we become better acquainted with the Universe, and astronomical history is littered with now-obsolete phrases to describe objects in the night sky, such as “spiral nebulae” for spiral galaxies or “inferior planets” for Mercury and Venus.

Image Credit: Gerhard Hüdepohl/ESO

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ESO's La Silla Observatory stretches out before your eyes in this image taken by ESO Photo Ambassador Gerhard Hüdepohl. This perspective looks down from a mountaintop in the Chilean Atacama Desert, capturing numerous telescopes and support buildings winding through the barren, remote landscape.

The telescope sitting proudly in the foreground is the ESO 3.6-metre telescope, with its curved white dome and grey base. A small bridge connects the telescope to a similarly white-domed, skinnier cylinder — the now-decommissioned ESO Coudé’ Auxiliary Telescope. In the distant background, a series of low, rectangular buildings can be seen sprawling across the mountainside; these include the site’s operations centre, dormitories, and a hotel.

As this image attests, no other signs of human civilisation exist for many kilometres around. Sitting at a challenging altitude of 2400 metres and on the outskirts of the driest desert on the planet, La Silla has little chance of becoming a hotbed of residential and commercial development. Instead, its splendid isolation makes La Silla one of the best places on Earth to conduct astronomy, with dark skies that are free of image-obscuring clouds most nights of the year.

Image Credit: ESA/Hubble & NASA, F. Pacaud, D. Coe

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This packed ESA/Hubble Picture of the Week showcases the galaxy cluster ACO S 295, as well as a jostling crowd of background galaxies and foreground stars. Galaxies of all shapes and sizes populate this image, ranging from stately spirals to fuzzy ellipticals. As well as a range of sizes, this galactic menagerie boasts a range of orientations, with spiral galaxies such as the one at the centre of this image appearing almost face on, and some edge-on spiral galaxies visible only as thin slivers of light.

The cluster dominates the centre of this image, both visually and physically. The huge mass of the galaxy cluster has gravitationally lensed the background galaxies, distorting and smearing their shapes. As well as providing astronomers with a natural magnifying glass with which to study distant galaxies, gravitational lensing has subtly framed the centre of this image, producing a visually striking scene.