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The Space and Astronomy Thread

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And while you're right that scientists probably don't know as much as we think they do in reality a scientist is someone who asks questions, knowing they don't know the answer, to determine ways in which they can find the answer they are looking for.

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Actually it is more than just an educated the guess. The reason they are able to come up with an approximation of the age of the universe, galaxies, stars etc. is because of the speed of light. Light takes time to travel through space and although light moves very quickly, over the vast distances in space it take an enormous amount of time to travel that far. So the deeper into space you look the futher back into time you look. You can calculate how long that light took to travel from its point of origin to the telescope into which those photons now enter. There is a veil or a block at just under 14 billion light years. This is the distance to the background radiation or in other words the big bang. Since we can't look past that veil the logic is that there is nothing before that time and hence the begining of the universe. While you are correct that it is just a theory that number is far from random and has been brought about by empirical and observed evidence.

So if the light from a spiral galaxy 11 billion light-years away is just now reaching earth, logic dictates that that galaxy is 11 billion years old.

If you look up Ole Rømer you can find out how he discovered the speed of light, its a pretty cool and his calculations from the 1600s were almost bang on what we know today is the speed of light with modern equiment used for measuring the speed.

And while you're right that scientists probably don't know as much as we think they do in reality a scientist is someone who asks questions, knowing they don't know the answer, to determine ways in which they can find the answer they are looking for.

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Who knows when the universe was created. I question the big bang theory since there isn't any conclusive evidence to this "big bang" that created the universe. How do we even know that there was a big bang? The universe could be 300 billion years old or it could be 14 billion years old. At least we could find out what the age of Earth is through carbon dating but not sure how we could validate the age of universe.

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Actually it is more than just an educated the guess. The reason they are able to come up with an approximation of the age of the universe, galaxies, stars etc. is because of the speed of light. Light takes time to travel through space and although light moves very quickly, over the vast distances in space it take an enormous amount of time to travel that far. So the deeper into space you look the futher back into time you look. You can calculate how long that light took to travel from its point of origin to the telescope into which those photons now enter. There is a veil or a block at just under 14 billion light years. This is the distance to the background radiation or in other words the big bang. Since we can't look past that veil the logic is that there is nothing before that time and hence the begining of the universe. While you are correct that it is just a theory that number is far from random and has been brought about by empirical and observed evidence.

So if the light from a spiral galaxy 11 billion light-years away is just now reaching earth, logic dictates that that galaxy is 11 billion years old.

If you look up Ole Rømer you can find out how he discovered the speed of light, its a pretty cool and his calculations from the 1600s were almost bang on what we know today is the speed of light with modern equiment used for measuring the speed.

And while you're right that scientists probably don't know as much as we think they do in reality a scientist is someone who asks questions, knowing they don't know the answer, to determine ways in which they can find the answer they are looking for.

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And how is it determined that the light has just now reached here? Because a scientist just noticed? It's a very big universe, it's not like we can keep tabs of every point of light nor have been up to now.

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And how is it determined that the light has just now reached here? Because a scientist just noticed? It's a very big universe, it's not like we can keep tabs of every point of light nor have been up to now.

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Who knows when the universe was created. I question the big bang theory since there isn't any conclusive evidence to this "big bang" that created the universe. How do we even know that there was a big bang? The universe could be 300 billion years old or it could be 14 billion years old. At least we could find out what the age of Earth is through carbon dating but not sure how we could validate the age of universe.

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Hubble Portrays a Dusty Spiral Galaxy

09.28.12

The NASA/ESA Hubble Space Telescope has provided us with another outstanding image of a nearby galaxy. This week, we highlight the galaxy NGC 4183, seen here with a beautiful backdrop of distant galaxies and nearby stars. Located about 55 million light-years from the sun and spanning about eighty thousand light-years, NGC 4183 is a little smaller than the Milky Way. This galaxy, which belongs to the Ursa Major Group, lies in the northern constellation of Canes Venatici (The Hunting Dogs).

NGC 4183 is a spiral galaxy with a faint core and an open spiral structure. Unfortunately, this galaxy is viewed edge-on from the Earth, and we cannot fully appreciate its spiral arms. But we can admire its galactic disk.

The disks of galaxies are mainly composed of gas, dust and stars. There is evidence of dust over the galactic plane, visible as dark intricate filaments that block the visible light from the core of the galaxy. In addition, recent studies suggest that this galaxy may have a bar structure. Galactic bars are thought to act as a mechanism that channels gas from the spiral arms to the center, enhancing star formation, which is typically more pronounced in the spiral arms than in the bulge of the galaxy.

British astronomer William Herschel first observed NGC 4183 on 14 January 1778.

This picture was created from visible and infrared images taken with the Wide Field Channel of the Advanced Camera for Surveys. The field of view is approximately 3.4 arcminutes wide.

This image uses data identified by Luca Limatola in the Hubble's Hidden Treasures image processing competition.

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Hubble Catches Glowing Gas and Dark Dust in a Side-On Spiral

09.21.12

The NASA/ESA Hubble Space Telescope has produced a sharp image of NGC 4634, a spiral galaxy seen exactly side-on. Its disk is slightly warped by ongoing interactions with a nearby galaxy, and it is crisscrossed by clearly defined dust lanes and bright nebulae.

NGC 4634, which lies around 70 million light-years from Earth in the constellation of Coma Berenices, is one of a pair of interacting galaxies. Its neighbor, NGC 4633, lies just outside the upper right corner of the frame, and is visible in wide-field views of the galaxy. While it may be out of sight, it is not out of mind: its subtle effects on NGC 4634 are easy to see to a well-trained eye.

Gravitational interactions pull the neat spiral forms of galaxies out of shape as they get closer to each other, and the disruption to gas clouds triggers vigorous episodes of star formation. While this galaxy’s spiral pattern is not directly visible thanks to our side-on perspective, its disk is slightly warped, and there is clear evidence of star formation.

Along the full length of the galaxy, and scattered around parts of its halo, are bright pink nebulae. Similar to the Orion Nebula in the Milky Way, these are clouds of gas that are gradually coalescing into stars. The powerful radiation from the stars excites the gas and makes it light up, much like a fluorescent sign. The large number of these star formation regions is a telltale sign of gravitational interaction.

The dark filamentary structures that are scattered along the length of the galaxy are caused by cold interstellar dust blocking some of the starlight.

Hubble’s image is a combination of exposures in visible light produced by Hubble’s Advanced Camera for Surveys and the Wide Field and Planetary Camera 2.

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This week, we highlight the galaxy NGC 4183, seen here with a beautiful backdrop of distant galaxies and nearby stars. Located about 55 million light-years from the sun and spanning about eighty thousand light-years, NGC 4183 is a little smaller than the Milky Way. This galaxy, which belongs to the Ursa Major Group, lies in the northern constellation of Canes Venatici (The Hunting Dogs).
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A high-powered camera that NOAA calls "the most powerful sky-mapping machine ever created" has caught its first glimpse of some of the Universe's most far-flung galaxies — and they are an absolute wonder to behold. {C

New Dark Energy Telescope Can Photograph Galaxies up to 8 Billion Light-Years From Earth

"the most powerful sky-mapping machine ever created" has caught its first glimpse of some of the Universe's most far-flung galaxies — and they are an absolute wonder to behold. {C}

The so-called "Dark Energy Camera" (a 570-megapixel astronomical-imaging behemoth) will be used in the eponymous Dark Energy Survey to scan the depths of space for signs of — you guessed it — dark energy. While this form of energy is thought to comprise upwards of 70% of the Universe and drive its ever-accelerating expansion, it remains one of the most enigmatic topics of investigation in modern Cosmology.

For the next five years, the camera — which is housed inside the Blanco telescope, high in the mountains of South America's Atacama desert — will be used to create detailed color images of one-eighth of the sky. Given that the camera is capable of detecting light from cosmic entities as much as 8 billion light years from Earth, astronomers think that the Dark Energy Camera will be used to identify and study upwards of 300 million galaxies, 100,000 galaxy clusters and 4,000 supernovae. In the process, they hope to unlock some of the secrets behind the Universe's expansion.

Hundreds of millions of galaxies. And it's just sent back its first batch. Featured below are some of the first images to be captured by the DECam, released earlier today by Fermilab (the famed accelerator lab actually built the camera).

A high-powered camera that NOAA calls "the most powerful sky-mapping machine ever created" has caught its first glimpse of some of the Universe's most far-flung galaxies — and they are an absolute wonder to behold. {C}

The so-called "Dark Energy Camera" (a 570-megapixel astronomical-imaging behemoth) will be used in the eponymous Dark Energy Survey to scan the depths of space for signs of — you guessed it — dark energy. While this form of energy is thought to comprise upwards of 70% of the Universe and drive its ever-accelerating expansion, it remains one of the most enigmatic topics of investigation in modern Cosmology.

For the next five years, the camera — which is housed inside the Blanco telescope, high in the mountains of South America's Atacama desert — will be used to create detailed color images of one-eighth of the sky. Given that the camera is capable of detecting light from cosmic entities as much as 8 billion light years from Earth, astronomers think that the Dark Energy Camera will be used to identify and study upwards of 300 million galaxies, 100,000 galaxy clusters and 4,000 supernovae. In the process, they hope to unlock some of the secrets behind the Universe's expansion.

Hundreds of millions of galaxies. And it's just sent back its first batch. Featured below are some of the first images to be captured by the DECam, released earlier today by Fermilab (the famed accelerator lab actually built the camera). Enjoy the view:

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Zoomed-in image from the Dark Energy Camera of the barred spiral galaxy NGC 1365, in the Fornax cluster of galaxies, which lies about 60 million light years from Earth

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Astronomers Uncover A Surprising Trend in Galaxy Evolution

A study of 544 star-forming galaxies observed by the Keck and Hubble telescopes shows that disk galaxies like our own Milky Way unexpectedly reached their current state long after much of the universe's star formation had ceased. Over the past 8 billion years, the galaxies lose chaotic motions and spin faster as they develop into settled disk galaxies. Credit: NASA's Goddard Space Flight Center

A comprehensive study of hundreds of galaxies observed by the Keck telescopes in Hawaii and NASA's Hubble Space Telescope has revealed an unexpected pattern of change that extends back 8 billion years, or more than half the age of the universe.

"Astronomers thought disk galaxies in the nearby universe had settled into their present form by about 8 billion years ago, with little additional development since," said Susan Kassin, an astronomer at NASA's Goddard Space Flight Center in Greenbelt, Md., and the study's lead researcher. "The trend we've observed instead shows the opposite, that galaxies were steadily changing over this time period."

Today, star-forming galaxies take the form of orderly disk-shaped systems, such as the Andromeda Galaxy or the Milky Way, where rotation dominates over other internal motions. The most distant blue galaxies in the study tend to be very different, exhibiting disorganized motions in multiple directions. There is a steady shift toward greater organization to the present time as the disorganized motions dissipate and rotation speeds increase. These galaxies are gradually settling into well-behaved disks.

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This plot shows the fractions of settled disk galaxies in four time spans, each about 3 billion years long. There is a steady shift toward higher percentages of settled galaxies closer to the present time. At any given time, the most massive galaxies are the most settled. More distant and less massive galaxies on average exhibit more disorganized internal motions, with gas moving in multiple directions, and slower rotation speeds. Credit: NASA's Goddard Space Flight Center

› Download hi-res image

Blue galaxies -- their color indicates stars are forming within them -- show less disorganized motions and ever-faster rotation speeds the closer they are observed to the present. This trend holds true for galaxies of all masses, but the most massive systems always show the highest level of organization.

Researchers say the distant blue galaxies they studied are gradually transforming into rotating disk galaxies like our own Milky Way.

"Previous studies removed galaxies that did not look like the well-ordered rotating disks now common in the universe today," said co-author Benjamin Weiner, an astronomer at the University of Arizona in Tucson. "By neglecting them, these studies examined only those rare galaxies in the distant universe that are well-behaved and concluded that galaxies didn't change."

Rather than limit their sample to certain galaxy types, the researchers instead looked at all galaxies with emission lines bright enough to be used for determining internal motions. Emission lines are the discrete wavelengths of radiation characteristically emitted by the gas within a galaxy. They are revealed when a galaxy's light is separated into its component colors. These emission lines also carry information about the galaxy's internal motions and distance.

Simulations such as this will help astronomers better understand the new findings in galaxy evolution. It tracks the development of a single disk galaxy from shortly after the Big Bang to the present day. Colors reveal old stars (red), young stars (white and bright blue) and the distribution of gas density (pale blue); the view is 300,000 light-years across. Credit: F. Governato and T. Quinn (Univ. of Washington), A. Brooks (Univ. of Wisconsin, Madison), and J. Wadsley (McMaster Univ.).

The team studied a sample of 544 blue galaxies from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey, a project that employs Hubble and the twin 10-meter telescopes at the W. M. Keck Observatory in Hawaii. Located between 2 billion and 8 billion light-years away, the galaxies have stellar masses ranging from about 0.3 percent to 100 percent of the mass of our home galaxy.

A paper describing these findings will be published Oct. 20 in The Astrophysical Journal.

The Milky Way galaxy must have gone through the same rough-and-tumble evolution as the galaxies in the DEEP2 sample, and gradually settled into its present state as the sun and solar system were being formed.

In the past 8 billion years, the number of mergers between galaxies large and small has decreased sharply. So has the overall rate of star formation and disruptions of supernova explosions associated with star formation. Scientists speculate these factors may play a role in creating the evolutionary trend they observe.

Now that astronomers see this pattern, they can adjust computer simulations of galaxy evolution until these models are able to replicate the observed trend. This will guide scientists to the physical processes most responsible for it

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Amazing Photo Captures 84 Million Stars in Our Milky Way Galaxy

by SPACE.com Staff

Date: 24 October 2012 Time: 06:00 AM ET

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Astronomers have catalogued 84 million stars at the heart of the Milky Way galaxy using an enormous cosmic photo snapped by a telescope in Chile, a view that is billed as the largest survey ever of the stars in our galaxy's core.

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This very wide-field view of the Milky Way shows the extent of the 84-million-star VISTA infrared image of the center of the galaxy (delineated by red rectangle).

CREDIT: ESO/Nick Risinger (skysurvey.org)

View full size image

Astronomers identified 173 million different objects in the 9-billion-pixel image, of which 84 million could be confirmed as stars. The rest were distant objects such as galaxies, or they were too faint or blended to be identified conclusively.

Saito and his team then plotted the brightness of each star against its color, creating a color-magnitude diagram with 84 million data points. These diagrams are valuable tools, helping astronomers study star properties such as temperature, mass and age.

"Each star occupies a particular spot in this diagram at any moment during its lifetime," Minniti said. "Where it falls depends on how bright it is and how hot it is. Since the new data gives us a snapshot of all the stars in one go, we can now make a census of all the stars in this part of the Milky Way."

The astronomers are making their data publicly available, so other research teams can use it to make exciting finds of their own.

The team published their results in the August issue of the journal Astronomy & Astrophysics

http://www.space.com/18191-new-star-catalog-largest-ever-84-million-suns-video.html

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Although it's not as impressive as galaxies, this seems like a good place to post that for the last week or so, there have been two very bright planets in the morning sky (haven't checked this morning yet, to see if they're still visible)

The brightest of the two is low in the southern sky and is most likely Venus. Higher and more to the NW (above and left of the moon) is the other, which by my guess, is Jupiter.

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Although it's not as impressive as galaxies, this seems like a good place to post that for the last week or so, there have been two very bright planets in the morning sky (haven't checked this morning yet, to see if they're still visible)

The brightest of the two is low in the southern sky and is most likely Venus. Higher and more to the NW (above and left of the moon) is the other, which by my guess, is Jupiter.

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A Ghost in Cepheus

Described as a "dusty curtain" or "ghostly apparition," mysterious reflection nebula VdB 152 really is very faint. Far from your neighborhood on this Halloween Night, the cosmic phantom is nearly 1,400 light-years away. Also catalogued as Ced 201, it lies along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of interstellar dust in the region block light from background stars or scatter light from the embedded bright star giving parts of the nebula a characteristic blue color. Ultraviolet light from the star is also thought to cause a dim reddish luminescence in the nebular dust. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud's velocity. This deep telescopic image of the region spans about 7 light-years.

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Spiral galaxies aren't rare! We live in one! Out in the spirally arm no less!

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Scientists Monitor Comet Breakup

11.02.12

704424main1_comet3frags20121102-673.jpg Comet 168P-Hergenrother was imaged by the NOAO/Gemini telescope on Nov. 2, 2011 at about 6 a.m. UTC. Image credit: NASA/JPL-Caltech/NOAO/Gemini › Full view

The Hergenrother comet is currently traversing the inner-solar system. Amateur and professional astronomers alike have been following the icy-dirt ball over the past several weeks as it has been generating a series of impressive outbursts of cometary-dust material. Now comes word that the comet's nucleus has taken the next step in its relationship with Mother Nature.

"Comet Hergenrother is splitting apart," said Rachel Stevenson, a post-doctoral fellow working at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Using the National Optical Astronomy Observatory's Gemini North Telescope on top of Mauna Kea, Hawaii, we have resolved that the nucleus of the comet has separated into at least four distinct pieces resulting in a large increase in dust material in its coma."

With more material to reflect the sun's rays, the comet's coma has brightened considerably.

"The comet fragments are considerably fainter than the nucleus," said James Bauer, the deputy principal investigator for NASA's NEOWISE mission, from the California Institute of Technology. "This is suggestive of chunks of material being ejected from the surface."

The comet's fragmentation event was initially detected on Oct. 26 by a team of astronomers from the Remanzacco Observatory, using the Faulkes Telescope North in Haleakala, Hawaii. The initial fragment was also imaged by the WIYN telescope group at Kitt Peak National Observatory in Arizona.

For those interested in viewing Hergenrother, with a larger-sized telescope and a dark sky, the comet can be seen in between the constellations of Andromeda and Lacerta.

The orbit of comet 168P/Hergenrother comet is well understood. The comet, nor any of its fragments, are a threat to Earth

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Hubble Sees an Unexpected Population of Young-Looking Stars

11.02.12

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› Larger image

The NASA/ESA Hubble Space Telescope offers an impressive view of the center of globular cluster NGC 6362. The image of this spherical collection of stars takes a deeper look at the core of the globular cluster, which contains a high concentration of stars with different colors.

Tightly bound by gravity, globular clusters are composed of old stars, which, at around 10 billion years old, are much older than the sun. These clusters are fairly common, with more than 150 currently known in our galaxy, the Milky Way, and more which have been spotted in other galaxies.

Globular clusters are among the oldest structures in the Universe that are accessible to direct observational investigation, making them living fossils from the early years of the cosmos.

Astronomers infer important properties of globular clusters by looking at the light from their constituent stars. For many years, they were regarded as ideal laboratories for testing the standard stellar evolution theory. Among other things, this theory suggests that most of the stars within a globular cluster should be of a similar age.

Recently, however, high precision measurements performed in numerous globular clusters, primarily with the Hubble Space Telescope, have led some to question this widely accepted theory. In particular, certain stars appear younger and bluer than their companions, and they have been dubbed blue stragglers. NGC 6362 contains many of these stars.

Since they are usually found in the core regions of clusters, where the concentration of stars is large, the most likely explanation for this unexpected population of objects seems to be that they could be either the result of stellar collisions or transfer of material between stars in binary systems. This influx of new material would heat up the star and make it appear younger than its neighbors.

NGC 6362 is located about 25 000 light-years from Earth in the constellation of Ara (The Altar). British astronomer James Dunlop first observed this globular cluster on 30 June 1826.

This image was created combining ultraviolet, visual and infrared images taken with the Wide Field Channel of the Advanced Camera for Surveys and the Wide Field Camera 3. An image of NGC 6362 taken by the MPG/ESO 2.2-meter telescope will be published by the European Southern Observatory on Wednesday.

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