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Guy Laliberte

Photographs of Earth taken during an 11 day trip in space.

(click pics to enlarge)

(Source: onedrop.org, via infinity-imagined)

NGC 1232 AND THE GRAND DESIGN
The term “grand design spiral galaxy” is merely a classification, a method of categorizing a galaxy’s structure, but the lofty language accurately captures the majestic appearance of such galaxies.
Grand design spirals, like NGC 1232 shown here, only account for about 10% of all known spiral galaxies, and yet they are iconic. When imagining a galaxy, the perfect spiral shape and clearly-defined arms are common imagery, even though more tightly-wound flocculent spirals or less-defined spirals are far more common. 
Perhaps our preference for the perfect spiral is an instinctive aesthetic. The famous Fibonacci spiral, after all, is found throughout nature, occurring in everything from plant structure to the proportions of the human body [Read more about Fibonacci’s sequence here]. There is a certain pleasing symmetry to the pervasiveness of Fibonacci spirals, and our eyes find them easy to follow. 
Galaxies such as NGC 1232, located 60 million light-years away in Eridanus, surely have no regard for our aesthetic preferences. Their beautiful arrangements are a natural consequence of physics.
So how do these galaxies get their arms? It’s easy to visualize solid body rotation, or the rotation of points along a flat plane as they are drawn in toward the center. The same phenomenon happens as you watch water circle the shower drain. The problem, however, is that if galaxies followed this pattern, their arms would be tightly wound at a fast rate, and we wouldn’t see such beautiful spirals. This is known as the “winding problem.” Given the mass at the center of a galaxy, it is just not possible that such clearly-defined spiral arms are just stars in a simple orbit around the center.
In the 1960s, scientists C.C. Lin and Frank Shu proposed the density wave theory, which posits that the gravitational interaction between stars and other matter in the galaxy prevents the so-called winding problem. The idea is that the arms are not actually a result of matter, but rather of varying density.
The theory can be compared to a traffic jam. As cars get backed up on the highway, the density of the traffic jam will increase as more cars move toward the center of the jam in an attempt to get to areas of lower density. The location of an individual car might change, but the overall density of the traffic jam does not go through any significant changes Similarly, the stars and other matter that make up NGC 1232’s arms may be pulled along by gravity, but they are moving through the density waves that make up the arms.
Newer research suggests that even this explanation is too simple. Even when accounting for density waves, the longevity of these spiral arms still isn’t quite explained. In 2011, researchers examined 12 nearby spiral galaxies in order to test the density wave theory. If Lin and Shu’s theory was correct, the researchers expected to find a progressive variation in areas of star formation. Instead, the three different phases of star formation they were looking for were scattered throughout the arm. This led to two possible conclusions: either the spiral arms repeatedly dissipate and reform, or the density waves contain variations in pattern speeds that would muddle the areas of star formation. 
Ultimately, it is a question that will be settled by more sophisticated modeling processes and increased research. Though the designs of galaxies like NGC 1232 are pleasantly simple, it’s clear that the same can’t be said for the mechanisms by which they form.
-RLO
Image: FORS, 8.2-meter VLT Antu, ESO
Sources: 1, 2, 3, 4 View high resolution

NGC 1232 AND THE GRAND DESIGN

The term “grand design spiral galaxy” is merely a classification, a method of categorizing a galaxy’s structure, but the lofty language accurately captures the majestic appearance of such galaxies.

Grand design spirals, like NGC 1232 shown here, only account for about 10% of all known spiral galaxies, and yet they are iconic. When imagining a galaxy, the perfect spiral shape and clearly-defined arms are common imagery, even though more tightly-wound flocculent spirals or less-defined spirals are far more common. 

Perhaps our preference for the perfect spiral is an instinctive aesthetic. The famous Fibonacci spiral, after all, is found throughout nature, occurring in everything from plant structure to the proportions of the human body [Read more about Fibonacci’s sequence here]. There is a certain pleasing symmetry to the pervasiveness of Fibonacci spirals, and our eyes find them easy to follow. 

Galaxies such as NGC 1232, located 60 million light-years away in Eridanus, surely have no regard for our aesthetic preferences. Their beautiful arrangements are a natural consequence of physics.

So how do these galaxies get their arms? It’s easy to visualize solid body rotation, or the rotation of points along a flat plane as they are drawn in toward the center. The same phenomenon happens as you watch water circle the shower drain. The problem, however, is that if galaxies followed this pattern, their arms would be tightly wound at a fast rate, and we wouldn’t see such beautiful spirals. This is known as the “winding problem.” Given the mass at the center of a galaxy, it is just not possible that such clearly-defined spiral arms are just stars in a simple orbit around the center.

In the 1960s, scientists C.C. Lin and Frank Shu proposed the density wave theory, which posits that the gravitational interaction between stars and other matter in the galaxy prevents the so-called winding problem. The idea is that the arms are not actually a result of matter, but rather of varying density.

The theory can be compared to a traffic jam. As cars get backed up on the highway, the density of the traffic jam will increase as more cars move toward the center of the jam in an attempt to get to areas of lower density. The location of an individual car might change, but the overall density of the traffic jam does not go through any significant changes Similarly, the stars and other matter that make up NGC 1232’s arms may be pulled along by gravity, but they are moving through the density waves that make up the arms.

Newer research suggests that even this explanation is too simple. Even when accounting for density waves, the longevity of these spiral arms still isn’t quite explained. In 2011, researchers examined 12 nearby spiral galaxies in order to test the density wave theory. If Lin and Shu’s theory was correct, the researchers expected to find a progressive variation in areas of star formation. Instead, the three different phases of star formation they were looking for were scattered throughout the arm. This led to two possible conclusions: either the spiral arms repeatedly dissipate and reform, or the density waves contain variations in pattern speeds that would muddle the areas of star formation. 

Ultimately, it is a question that will be settled by more sophisticated modeling processes and increased research. Though the designs of galaxies like NGC 1232 are pleasantly simple, it’s clear that the same can’t be said for the mechanisms by which they form.

-RLO

Image: FORS8.2-meter VLT AntuESO

Sources: 1, 2, 3, 4

NGC 3455This new image from the Hubble Space Telescope’s Advanced Camera for Surveys (ACS) provides a gorgeous view of spiral galaxy NGC 3455. It lies 65 million light years away from Earth in the constellation Leo.Famed astronomer Edwin Hubble devised a classification system for galaxy types, known as the Hubble Sequence. In this system, NGC 3455 belongs to the barred spiral (SB) category, which feature a bar of stars running through the galaxy’s central bulge. Barred spirals make up the majority of all spirals, accounting for about two thirds of the total. Barred spiral galaxies are further broken down into three subgroups based on the appearance of their spiral arms: SBa galaxies have tightly wound arms, SBc types have looser arms, and SBb galaxies, like this one, lie somewhere in between.NGC 3455 is part of a pair of galaxies. The other part of the duo is NGC 3454, an edge-on spiral that is separated by 50,000 to 60,000 light years distance and lies outside the frame of this image. This pair is part of the NGC 3370 group, which contains at least eight major galaxies. The NGC 3370 group, in turn, is part of the Leo II groups, a collection of over 80 major galaxies.-JFImage credit: ESA/Hubble, NASA, Nick RoseSources: 1, 2 View high resolution

NGC 3455

This new image from the Hubble Space Telescope’s Advanced Camera for Surveys (ACS) provides a gorgeous view of spiral galaxy NGC 3455. It lies 65 million light years away from Earth in the constellation Leo.

Famed astronomer Edwin Hubble devised a classification system for galaxy types, known as the Hubble Sequence. In this system, NGC 3455 belongs to the barred spiral (SB) category, which feature a bar of stars running through the galaxy’s central bulge. Barred spirals make up the majority of all spirals, accounting for about two thirds of the total. Barred spiral galaxies are further broken down into three subgroups based on the appearance of their spiral arms: SBa galaxies have tightly wound arms, SBc types have looser arms, and SBb galaxies, like this one, lie somewhere in between.

NGC 3455 is part of a pair of galaxies. The other part of the duo is NGC 3454, an edge-on spiral that is separated by 50,000 to 60,000 light years distance and lies outside the frame of this image. This pair is part of the NGC 3370 group, which contains at least eight major galaxies. The NGC 3370 group, in turn, is part of the Leo II groups, a collection of over 80 major galaxies.

-JF

Image credit: ESA/Hubble, NASA, Nick Rose

Sources: 1, 2

Lunar Eclipse with LaserThis gorgeous view of the April 15th Lunar Eclipse was captured on top of Mauna Kea in Hawaii by photographer Andrew Richard Hara.The top of Mauna Kea is one of the best places on Earth to observe the skies. It’s over 4000 meters high, putting it above many weather systems, and it is in the middle of the Pacific Ocean, cutting down on light and particulate pollution from cities. Multiple observatories sit atop Mauna Kea, including the twin Keck Telescopes seen here at the right.The Keck Telescopes have the ability to fire a laser into the sky; the laser is used to allow the optics of the telescope to correct for how light is traveling through the Earth’s atmosphere, as well as potentially defend the Earth from alien attack (sarcasm).That setup creates this photo…a laser firing into the night from a telescope on top of a volcano during a lunar eclipse.Was that phrase as fun to read as it was to write? Because it was awesome to write.-JBBImage credit and copyright: Andrew Richard HaraPhotographer | Explorer | Imaging SpecialistShared here with photographer’s permission. View high resolution

Lunar Eclipse with Laser

This gorgeous view of the April 15th Lunar Eclipse was captured on top of Mauna Kea in Hawaii by photographer Andrew Richard Hara.

The top of Mauna Kea is one of the best places on Earth to observe the skies. It’s over 4000 meters high, putting it above many weather systems, and it is in the middle of the Pacific Ocean, cutting down on light and particulate pollution from cities. Multiple observatories sit atop Mauna Kea, including the twin Keck Telescopes seen here at the right.

The Keck Telescopes have the ability to fire a laser into the sky; the laser is used to allow the optics of the telescope to correct for how light is traveling through the Earth’s atmosphere, as well as potentially defend the Earth from alien attack (sarcasm).

That setup creates this photo…a laser firing into the night from a telescope on top of a volcano during a lunar eclipse.

Was that phrase as fun to read as it was to write? Because it was awesome to write.

-JBB

Image credit and copyright: Andrew Richard Hara
Photographer | Explorer | Imaging Specialist
Shared here with photographer’s permission.

HUBBLE TAKES A CROSS-SECTION OF THE UNIVERSEThis image of a galaxy cluster, taken by the NASA/ESA Hubble Space Telescope, shows various objects at different distances and stages in their development. The objects in the image range in distance from relatively close to us to others that were seen during the early Universe; most lie about five billion light-years from Earth.Though many of the objects appear close to each other, they may in fact be billions of light-years apart; this is due to many of the groups of galaxies lying along our line of sight. Gravitational lensing also means that galaxies in the distant background appear distorted.Gravitational lensing can amplify the light seen from distant objects, allowing telescopes like Hubble to see objects that would usually be too far away to view. The lensing itself is caused by the bending of the space-time continuum by large galaxies within our line of sight to distant objects. CLASS B1608+656, a small loop in the centre of the image, is one of the lens systems visible. Two of the foreground galaxies are distorted and amplify the light from a distant quasar called QSO-160913+653228. The light from this quasar has taken nine billion years to reach us.There are two other gravitational lenses within this image: two galaxies, known as Fred and Ginger, contain enough mass to distort the light from objects behind them. Fred is also known as [FMK2006] ACS J160919+6532, and is located near the lens galaxies in CLASS B1608+656, while Ginger ([FMK2006] ACS J160910+6532) is located much closer to us. Both galaxies can be seen near to CLASS B1608+656 in the central region of this image.The image is made up of visible and infrared observations with a total exposure time of 14 hours. The view displays objects that are about a billion times fainter than what humans would see with their naked eye.-TELCredit: NASA, ESA View high resolution

HUBBLE TAKES A CROSS-SECTION OF THE UNIVERSE

This image of a galaxy cluster, taken by the NASA/ESA Hubble Space Telescope, shows various objects at different distances and stages in their development. The objects in the image range in distance from relatively close to us to others that were seen during the early Universe; most lie about five billion light-years from Earth.

Though many of the objects appear close to each other, they may in fact be billions of light-years apart; this is due to many of the groups of galaxies lying along our line of sight. Gravitational lensing also means that galaxies in the distant background appear distorted.

Gravitational lensing can amplify the light seen from distant objects, allowing telescopes like Hubble to see objects that would usually be too far away to view. The lensing itself is caused by the bending of the space-time continuum by large galaxies within our line of sight to distant objects. 

CLASS B1608+656, a small loop in the centre of the image, is one of the lens systems visible. Two of the foreground galaxies are distorted and amplify the light from a distant quasar called QSO-160913+653228. The light from this quasar has taken nine billion years to reach us.

There are two other gravitational lenses within this image: two galaxies, known as Fred and Ginger, contain enough mass to distort the light from objects behind them. Fred is also known as [FMK2006] ACS J160919+6532, and is located near the lens galaxies in CLASS B1608+656, while Ginger ([FMK2006] ACS J160910+6532) is located much closer to us. Both galaxies can be seen near to CLASS B1608+656 in the central region of this image.

The image is made up of visible and infrared observations with a total exposure time of 14 hours. The view displays objects that are about a billion times fainter than what humans would see with their naked eye.

-TEL

Credit: NASA, ESA

A CLOUD OF REDThis image was taken by ESO’s La Silla Observatory in Chile of a cloud of hydrogen called Gum 41. Hot stars within this nebula give off energetic radiation, causing the hydrogen around it to glow red. Though the clouds in this image appear thick and bright, its light is spread very thinly and the red glow is not seen well visually. Gum 41 is located 7300 light-years from Earth in an area of the southern sky in the constellation of Centaurus (The Centaur). There are many bright nebulae in this region, all associated with hot newborn stars that emit intense radiation which excites the hydrogen gas surrounding them, causing the hydrogen to glow red. Gum 41 was discovered by Australian astronomer Colin Gum, and included in his catalogue of 84 emission nebulae, published in 1955. The nebula is part of a much larger structure called the Lambda Centauri Nebula, also known as the Running Chicken Nebula.This image was created using data from the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. It is a combination of images taken through blue, green, and red filters, along with an image using a special filter designed to pick out the red glow from hydrogen.-TELCredit: ESO View high resolution

A CLOUD OF RED

This image was taken by ESO’s La Silla Observatory in Chile of a cloud of hydrogen called Gum 41. Hot stars within this nebula give off energetic radiation, causing the hydrogen around it to glow red. Though the clouds in this image appear thick and bright, its light is spread very thinly and the red glow is not seen well visually. 

Gum 41 is located 7300 light-years from Earth in an area of the southern sky in the constellation of Centaurus (The Centaur). There are many bright nebulae in this region, all associated with hot newborn stars that emit intense radiation which excites the hydrogen gas surrounding them, causing the hydrogen to glow red. 

Gum 41 was discovered by Australian astronomer Colin Gum, and included in his catalogue of 84 emission nebulae, published in 1955. The nebula is part of a much larger structure called the Lambda Centauri Nebula, also known as the Running Chicken Nebula.

This image was created using data from the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. It is a combination of images taken through blue, green, and red filters, along with an image using a special filter designed to pick out the red glow from hydrogen.

-TEL

Credit: ESO

jtotheizzoe:

myartexperiments:

Happy Earth Day

It’s like we’re dancing! The waltz of Terra Luna …
View high resolution

jtotheizzoe:

myartexperiments:

Happy Earth Day

It’s like we’re dancing! The waltz of Terra Luna …

Maybe this is a moon?This is another image captured by the Cassini spacecraft orbiting Saturn. See that tiny bright spot at the edge of the A-Ring? That spot is the subject of a paper just published in the journal Icarus and it’s really interesting; the scientists think it may be evidence of a newly formed Moon.The formation of Saturn’s moons is a process we’re still trying to understand. The Cassini mission has imaged many “moonlets” – tiny moons hanging out in the middle of Saturn’s rings probably formed when gravity brought pieces of ice from the rings together into small objects, but we’ve never seen one in the process of forming.Even tiny moonlets have enough gravity to disrupt the rings around them – that’s actually what you’re seeing here, the edge of the ring is brightened because of the gravity of an invisible object.The scientists, led by Dr. Murray from the Queen Mary University of London, estimate this new “moon”, if it is one, is probably only about 500 meters in diameter and may well be on its way out of the ring system where it could be considered a separate moon.These scientists believe this process may have contributed to the formation of Saturn’s larger moons. Those moons are made mostly of ice, like the rings, and if a process like this has occurred repeatedly it could have sent many tiny moonlets out from Saturn’s rings. Those moonlets could have then been captured by the gravity of Saturn’s larger moons, assembling larger bodies over time from mass stripped out of the gradually-shrinking rings.The object hasn’t been actually imaged – only the effects of its gravity have been seen, and thus it currently doesn’t have a name. The scientists informally know it as “Peggy”.-JBBImage credit: NASA/JPL/Space Science InstituteRead moreOriginal Paper

Maybe this is a moon?

This is another image captured by the Cassini spacecraft orbiting Saturn. See that tiny bright spot at the edge of the A-Ring? That spot is the subject of a paper just published in the journal Icarus and it’s really interesting; the scientists think it may be evidence of a newly formed Moon.

The formation of Saturn’s moons is a process we’re still trying to understand. The Cassini mission has imaged many “moonlets” – tiny moons hanging out in the middle of Saturn’s rings probably formed when gravity brought pieces of ice from the rings together into small objects, but we’ve never seen one in the process of forming.

Even tiny moonlets have enough gravity to disrupt the rings around them – that’s actually what you’re seeing here, the edge of the ring is brightened because of the gravity of an invisible object.

The scientists, led by Dr. Murray from the Queen Mary University of London, estimate this new “moon”, if it is one, is probably only about 500 meters in diameter and may well be on its way out of the ring system where it could be considered a separate moon.

These scientists believe this process may have contributed to the formation of Saturn’s larger moons. Those moons are made mostly of ice, like the rings, and if a process like this has occurred repeatedly it could have sent many tiny moonlets out from Saturn’s rings. Those moonlets could have then been captured by the gravity of Saturn’s larger moons, assembling larger bodies over time from mass stripped out of the gradually-shrinking rings.

The object hasn’t been actually imaged – only the effects of its gravity have been seen, and thus it currently doesn’t have a name. The scientists informally know it as “Peggy”.

-JBB

Image credit: NASA/JPL/Space Science Institute

Read more
Original Paper

Announcing Kepler 186-f: the First Earth-sized Exoplanet in the Habitable ZoneFor the past five years, the Kepler Space Telescope has allowed astronomers to observe over 3,800 potential exoplanets and confirm around 950 of them. Many of these planets have been discovered in what’s known as the goldilocks zone. This is an area around a host star where the conditions are right for liquid water to pool on a planet’s surface. Simply being in the habitable or goldilocks zone does not guarantee a planet will be habitable – the conditions have to be just right. Over the years, Kepler has spotted planets that were too hot or too large to truly be habitable. Today astronomers from NASA Ames and the SETI Institute have announced the discovery and validation of the first Earth-sized exoplanet orbiting its host star in the habitable zone. The host star, Kepler-186 is an older, dim red dwarf (or M dwarf) star. This system is home to five exoplanets, one of which could potentially have conditions ideal for life. The planet Kepler-186f, is on the outer edge of the habitable zone, orbiting its star once every 130 days and is approximately ten percent larger than Earth. The system is located approximately 500 light-years from Earth in the constellation Cygnus. Red dwarf stars are the most common stellar variety, with 7 out of every 10 stars in the Milky Way being M dwarf stars. Unlike our Sun, which is a yellow dwarf (G-type star), M dwarf stars are much cooler and dimmer. It is nearly impossible to determine the age of red dwarfs; however, their long life spans and cooler temperatures result in a closer habitable zone. M dwarf stars could very well be home to life beyond Earth. There are many characteristics of habitable planets aside from their location in the habitable zone – planet size and atmospheric conditions also play a role. Based on Kepler observations, astronomers have determined the size of Kepler-186f but not the composition or mass. Previous data indicates a planet the size of Kepler-186f would have a rocky composition similar to the Earth’s. Astronomers made this exciting discovery using the transitive method. The host star was observed and any dip in brightness would be indicative of another celestial body (such as a planet) crossing in front of it. Since Kepler-186f is only slightly larger than Earth and orbits fairly close to its star, we cannot directly observe it here on Earth. However with the upcoming Transiting Exoplanet Search Satellite (TESS) launching in 2017 and the James Webb Space Telescope (JWST) launching in 2018, we should soon be able to have a clearer picture of what Kepler-186f and other M dwarf planets are made of. -ALTImage & Source Credit: NASA/SETI Institute/JPL-Caltech View high resolution

Announcing Kepler 186-f: the First Earth-sized Exoplanet in the Habitable Zone

For the past five years, the Kepler Space Telescope has allowed astronomers to observe over 3,800 potential exoplanets and confirm around 950 of them. Many of these planets have been discovered in what’s known as the goldilocks zone. This is an area around a host star where the conditions are right for liquid water to pool on a planet’s surface. Simply being in the habitable or goldilocks zone does not guarantee a planet will be habitable – the conditions have to be just right. Over the years, Kepler has spotted planets that were too hot or too large to truly be habitable. Today astronomers from NASA Ames and the SETI Institute have announced the discovery and validation of the first Earth-sized exoplanet orbiting its host star in the habitable zone. 

The host star, Kepler-186 is an older, dim red dwarf (or M dwarf) star. This system is home to five exoplanets, one of which could potentially have conditions ideal for life. The planet Kepler-186f, is on the outer edge of the habitable zone, orbiting its star once every 130 days and is approximately ten percent larger than Earth. The system is located approximately 500 light-years from Earth in the constellation Cygnus. Red dwarf stars are the most common stellar variety, with 7 out of every 10 stars in the Milky Way being M dwarf stars. Unlike our Sun, which is a yellow dwarf (G-type star), M dwarf stars are much cooler and dimmer. It is nearly impossible to determine the age of red dwarfs; however, their long life spans and cooler temperatures result in a closer habitable zone. M dwarf stars could very well be home to life beyond Earth. 

There are many characteristics of habitable planets aside from their location in the habitable zone – planet size and atmospheric conditions also play a role. Based on Kepler observations, astronomers have determined the size of Kepler-186f but not the composition or mass. Previous data indicates a planet the size of Kepler-186f would have a rocky composition similar to the Earth’s. Astronomers made this exciting discovery using the transitive method. The host star was observed and any dip in brightness would be indicative of another celestial body (such as a planet) crossing in front of it. Since Kepler-186f is only slightly larger than Earth and orbits fairly close to its star, we cannot directly observe it here on Earth. However with the upcoming Transiting Exoplanet Search Satellite (TESS) launching in 2017 and the James Webb Space Telescope (JWST) launching in 2018, we should soon be able to have a clearer picture of what Kepler-186f and other M dwarf planets are made of. 

-ALT

Image & Source Credit: NASA/SETI Institute/JPL-Caltech