— Carl Sagan
An image of the region of sky around M74, the “Phantom Galaxy”, from the Digitized Sky Survey 2. The field-of-view is approximately 2.8 x 2.8 degrees.
Credit: NASA/ ESA/ Digitized Sky Survey 2/ Davide De Martin (ESA/Hubble)
Left: A GALEX ultraviolet image of the interacting galaxies M81 and M82, which lie 12 million light-years away in the constellation Ursa Major. The gravity from each galaxy dramatically affected the other during their last close encounter, 200 million years ago. Gas density waves rippling around M81 make it a grand design spiral. M82 is undergoing a starburst at its core, creating glowing fingers of hydrogen.
Right: A Hubble Space Telescope visible light image of bright blue star clusters found along a wispy bridge of gas that was tidally stretched between the two galaxies, and a third companion galaxy not seen in this picture. This is not the place astronomers expect to find star clusters because the density of gas is so low. Turbulence in the gas may have enhanced the density locally to trigger starbirth. The so-called “blue blobs” are clumped together in a structure called Arp’s Loop. Hubble reveals the clusters contain the equivalent of five Orion Nebulae. A Hubble plot of the stellar population in the clusters yields an age of approximately 200 million years, which coincides with the epoch of the collision.
Credit: NASA, ESA, and D. de Mello (Catholic University of America/GSFC)
— Carl Sagan (via scinerds)
Another GalaxyCredit: ESA/Hubble & NASA
Thursday, December 27, 2012
Galaxy ESO 318-13 lies millions of light-years from Earth, but Hubble Space Telescope shows it with remarkable clarity in this image. The bright star that appears to shine from within the galaxy actually belongs to our galaxy, the Milky Way, and sits much closer to us than ESO 318-13. Other galaxies appear as tiny discs throughout the photograph. A distant spiral galaxy clearly shines through ESO 318-13 at the right hand side of the image.
Herschel and Keck take census of the invisible universe
By combining the observing powers of ESA’s Herschel space observatory and the ground-based Keck telescopes, astronomers have characterised hundreds of previously unseen starburst galaxies, revealing extraordinary high star-formation rates across the history of the Universe.
Starburst galaxies give birth to hundreds of solar masses’ worth of stars each year in short-lived but intense events. By comparison, our own Milky Way Galaxy on average produces the equivalent of only one Sun-like star per year.
Starburst galaxies generate so much starlight that they should outshine our Galaxy hundreds to thousands of times over, but the enormous quantities of gas fuelling them also contain vast amounts of dust as a result of the frantic star formation.
The dust absorbs much of the visible light, meaning that many of them look quite insignificant in that part of the spectrum. However, the dust is warmed by the surrounding hot stars and re-emits the energy at far-infrared wavelengths.
Using ESA’s infrared Herschel space observatory, astronomers measured the temperature and brightness of thousands of dusty galaxies. From these, their star-formation rate could be then calculated.
To provide context to the observations and understand how star formation has changed over the Universe’s 13.7 billion year history, the distances to the galaxies were also needed.
With Herschel signposting the way, astronomers used spectrometers on the twin 10-metre W.M. Keck telescopes on Mauna Kea, Hawai‘i, and obtained the redshifts of 767 of the starburst galaxies.
Redshifts provide astronomers with a measure of how long the light from each galaxy has travelled across the Universe, which, in turn, indicates when in cosmic history the light from each galaxy was emitted.
For most of the galaxies it was found that the light has been travelling towards us for 10 billion years or less. About 5% of the galaxies are at even greater redshifts: their light was emitted when the Universe was only 1–3 billion years old.
How such large numbers of starburst galaxies formed during the first few billions of years of the Universe’s existence poses a vital problem for galaxy formation and evolution studies.
One leading theory proposes that a collision between two young galaxies could have sparked an intense short-lived phase of star formation. Another theory speculates that, when the Universe was young, individual galaxies had much more gas available to them to feed from, enabling higher rates of star formation without the need of collisions.
“Before Herschel, the largest similar survey of distant starbursts involved only 73 galaxies – we’ve improved on that by over a factor of ten in this combined survey with Keck to determine the characteristics of this important galaxy population,” adds Göran Pilbratt, ESA’s Herschel project scientist.
Image credit: ESA–C. Carreau/C. Casey (University of Hawai’i); COSMOS field: ESA/Herschel/SPIRE/HerMES Key Programme; Hubble images: NASA, ESA
This photo from the new Dark Energy Camera, taken in September 2012, shows the barred spiral galaxy NGC 1365, in the Fornax cluster of galaxies, which lies about 60 million light years from Earth.
In physical cosmology and astronomy, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe. Dark energy is the most accepted hypothesis to explain observations since the 1990s that indicate that the universe is expanding at an accelerating rate. In the standard model of cosmology, dark energy currently accounts for 73% of the total mass–energy of the universe.
There is one source of inspiration that has earned the attention of poets, artists and scientists alike, the night sky. Whether it be for spiritual reasons, such as the Native Americans who believed the stars were a world for their ancestors, or for reasons as practical as sailors navigating this world; the stars have been a guiding source for humanity for centuries. Poets, such as Edgar Allen Poe in his poem Evening Star, have turned to the stars as companions and muses burning in the cold darkness of night. Painters have also been known to draw on the stars for artistic guidance. One of the most well known paintings in all of history, Van Gogh’s Starry Night, serves as a tribute to the awe inspiring beauty possessed by these heavenly bodies. However, what science has to say about the stars may quite possibly trump the examples listed above in both their poetic and artful natures.
“We are all made of star stuff”, this is a quote made famous by the late Carl Sagan. When he spoke this phrase Sagan was referring to the scientific theory that all matter was first created in a star. Science has revealed the stars as the origin of all atoms larger than hydrogen. There are few ideas more poetic or more artful than the suggestion that all matter, all life, has a common origin in one of these guiding lights burning brightly in the night sky.
This installation consists of a visual exploration of the romance and splendor embodied by this scientific theory. The work entitled Star Stuff is an installation of living phosphorescent bacterial photographs of the cosmos taken by the Hubble telescope. Each celestial form is comprised of billions and billions of genetically engineered E. coli that have grown in such a pattern that they form a photographic reproduction of a celestial object. The installation is meant to instill in the viewer a sense of wonderment and awe reminiscent of the emotions experienced by poets and artists as they gazed at the stars. Suggesting that the scientific view of the universe is not cold and passionless, that in actuality, it is deeply poetic.