Starship Asterisk*

starsurfer wrote: ↑Wed Sep 05, 2018 10:15 am Sh2-278
https://www.hansonastronomy.com/sh2278
Copyright: Mark Hanson
SH2-278.jpg

starsurfer wrote: ↑Wed Sep 05, 2018 9:54 am NGC 5256
https://www.spacetelescope.org/news/heic1720/
Copyright: NASA, ESA

Click to view full size image

Image Credit: ESA/Hubble & NASA -- Acknowledgement: Judy Schmidt

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Gravity is so much a part of our daily lives that it is all too easy to forget its awesome power — but on a galactic scale, its power becomes both strikingly clear and visually stunning.

This image was taken with the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3) and shows an object named SDSS J1138+2754. It acts as a gravitational lens illustrates the true strength of gravity: A large mass — a galaxy cluster in this case — is creating such a strong gravitational field that it is bending the very fabric of its surroundings. This causes the billion-year-old light from galaxies sitting behind it to travel along distorted, curved paths, transforming the familiar shapes of spirals and ellipticals (visible in other parts of the image) into long, smudged arcs and scattered dashes.

Some distant galaxies even appear multiple times in this image. Since galaxies are wide objects, light from one side of the galaxy passes through the gravitational lens differently than light from the other side. When the galaxies’ light reaches Earth it can appear reflected, as seen with the galaxy on the lower left part of the lens, or distorted, as seen with the galaxy to the upper right.

This data were taken as part of a research project on star formation in the distant Universe, building on Hubble’s extensive legacy of deep-field images. Hubble observed 73 gravitationally-lensed galaxies for this project.

bystander wrote: ↑Mon Sep 10, 2018 4:30 pm Awesome Gravity
ESA Hubble Picture of the Week | 2018 Sep 10

Image Credit: ESA/Hubble & NASA -- Acknowledgement: Judy Schmidt

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Gravity is so much a part of our daily lives that it is all too easy to forget its awesome power — but on a galactic scale, its power becomes both strikingly clear and visually stunning.

This image was taken with the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3) and shows an object named SDSS J1138+2754. It acts as a gravitational lens illustrates the true strength of gravity: A large mass — a galaxy cluster in this case — is creating such a strong gravitational field that it is bending the very fabric of its surroundings. This causes the billion-year-old light from galaxies sitting behind it to travel along distorted, curved paths, transforming the familiar shapes of spirals and ellipticals (visible in other parts of the image) into long, smudged arcs and scattered dashes.

Some distant galaxies even appear multiple times in this image. Since galaxies are wide objects, light from one side of the galaxy passes through the gravitational lens differently than light from the other side. When the galaxies’ light reaches Earth it can appear reflected, as seen with the galaxy on the lower left part of the lens, or distorted, as seen with the galaxy to the upper right.

This data were taken as part of a research project on star formation in the distant Universe, building on Hubble’s extensive legacy of deep-field images. Hubble observed 73 gravitationally-lensed galaxies for this project.

Credit: ESO

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This image shows a dwarf galaxy in the southern constellation of Phoenix named, for obvious reasons, the Phoenix Dwarf.

The Phoenix Dwarf is unique in that it cannot be classified according to the usual scheme for dwarf galaxies; while its shape would label it as a spheroidal dwarf galaxy — which do not contain enough gas to form new stars — studies have shown the galaxy to have an associated cloud of gas nearby, hinting at recent star formation, and a population of young stars.

The gas cloud does not lie within the galaxy itself, but is still gravitationally bound to it — meaning that it will eventually fall back into the galaxy over time. Since the cloud is close by, it’s likely that the process that flung it outwards it is still ongoing. After studying the shape of the gas cloud, astronomers suspect the most likely cause of the ejection to be supernova explosions within the galaxy.

Credit: ESA/Hubble & NASA

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In the northern constellation of Coma Berenices (Berenice's Hair) lies the impressive Coma Cluster — a structure of over a thousand galaxies bound together by gravity. Many of these galaxies are elliptical types, as is the brighter of the two galaxies dominating this image: NGC 4860 (centre). However, the outskirts of the cluster also host younger spiral galaxies that proudly display their swirling arms. Again, this image shows a wonderful example of such a galaxy in the shape of the beautiful NGC 4858, which can be seen to the left of its bright neighbour and which stands out on account of its unusual, tangled, fiery appearance.

NGC 4858 is special. Rather than being a simple spiral, it is something called a “galaxy aggregate”, which is, just as the name suggests, a central galaxy surrounded by a handful of luminous knots of material that seem to stem from it, extending and tearing away and adding to or altering its overall structure. It is also experiencing an extremely high rate of star formation, possibly triggered by an earlier interaction with another galaxy. As we see it, NGC 4858 is forming stars so frantically that it will use up all of its gas long before it reaches the end of its life. The colour of its bright knots indicates that they are formed of hydrogen, which glows in various shades of bright red as it is energised by the many young, hot stars lurking within.

This scene was captured by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3), a powerful camera designed to explore the evolution of stars and galaxies in the early Universe.