from Tumblr http://ift.tt/1FG7bVG
via Peace Love Beauty Wisdom Learning Growth Evolution
Showing posts with label galaxies. Show all posts
Showing posts with label galaxies. Show all posts
Thursday, May 21, 2015
Tuesday, May 19, 2015
Wednesday, August 10, 2011
Four Unusual Views of the Andromeda Galaxy | ESA/Hubble
The Andromeda Galaxy is revealed in unprecedented detail in four archive observations from the NASA/ESA Hubble Space Telescope. They show stars and structure in the galaxy’s disc, the halo of stars that surrounds it, and a stream of stars left by a companion galaxy as it was torn apart and pulled in by the galaxy’s gravitational forces.
Picture of the Week of August 8, 2011 - Crowded, but Suspiciously Quiet? | ESA/Hubble
'The NASA/ESA Hubble Space Telescope has imaged part of the Hickson Compact Group 7, or HCG 7 for short. This grouping is composed of one lenticular (lens-shaped) and three spiral galaxies in close proximity. In this image, one of the spirals dominates the foreground, with many more distant galaxies peppering the background. Observing tightly-knit galaxy groups like HCG 7 is important because they evolve in a different way from their more spaced-out counterparts in less crowded regions of the Universe.
A recent study using Hubble data analysed the star clusters in HCG 7. Three hundred young clusters and 150 globular clusters were charted, and their ages and distributions measured. The results suggest that the rate of star formation has been fairly steady through time, although quite high in the central regions. Additional studies, including searches for material between the galaxies, hint that the stars in the HCG 7 galaxies formed by converting their gas without any gravitational influences caused by merging with other galaxies. This is puzzling, as the galaxies are depleting their supplies of gas at a rate that suggests that they have merged in the past.
This raises the question of whether the group really has evolved serenely, or if there are mysterious processes at work that are yet to be understood. The currently known information is contradictory and an encouragement for further studies to discover the real story behind HCG 7.'
Saturday, October 23, 2010
An Odd Planetary Nebula In Hercules | ESA/Hubble - Picture Of The Week
An Odd Planetary Nebula in Hercules
For as long as there been humans we have searched for our place in the cosmos. Where are we? Who are we? We find that we live on an insignificant planet of a hum-drum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people. This perspective is a courageous continuation of our penchant for constructing and testing mental models of the skies; the Sun as a red-hot stone, the stars as a celestial flame, the Galaxy as the backbone of night.
- Carl Sagan, Cosmos
The NASA/ESA Hubble Space Telescope has taken a striking high resolution image of the curious planetary nebula NGC 6210. Located about 6500 light-years away, in the constellation of Hercules, NGC 6210 was discovered in 1825 by the German astronomer Friedrich Georg Wilhelm Struve. Although in a small telescope it appears only as a tiny disc, it is fairly bright.
NGC 6210 is the last gasp of a star slightly less massive than our Sun at the final stage of its life cycle. The multiple shells of material ejected by the dying star form a superposition of structures with different degrees of symmetry, giving NGC 6210 its odd shape. This sharp image shows the inner region of this planetary nebula in unprecedented detail, where the central star is surrounded by a thin, bluish bubble that reveals a delicate filamentary structure. This bubble is superposed onto an asymmetric, reddish gas formation where holes, filaments and pillars are clearly visible.
The life of a star ends when the fuel available to its thermonuclear engine runs out. The estimated lifetime for a Sun-like star is some ten billion years. When the star is about to expire, it becomes unstable and ejects its outer layers, forming a planetary nebula and leaving behind a tiny, but very hot, remnant, known as white dwarf. This compact object, here visible at the centre of the image, cools down and fades very slowly. Stellar evolution theory predicts that our Sun will experience the same fate as NGC 6210 in about five billion years.
This picture was created from images taken with Hubble’s Wide Field Planetary Camera 2 through three filters: the broadband filter F555W (yellow) and the narrowband filters F656N (ionised hydrogen), F658N (ionised nitrogen) and F502N (ionised oxygen). The exposure times were 80 s, 140 s, 800 s and 700 s respectively and the field of view is only about 28 arcseconds across.
Credit:
ESA/Hubble and NASA
Subscribe to:
Posts (Atom)