“Earthrise,” as photographed by the Apollo 8 crew on Christmas Eve 1968, laid over NASA’s 2013 recreation using Lunar Reconnaissance Orbiter (LRO) data.

Credit: NASA/GSFC

Earthrise,” as photographed by the Apollo 8 crew on Christmas Eve 1968, laid over NASA’s 2013 recreation using Lunar Reconnaissance Orbiter (LRO) data.

Credit: NASA/GSFC

Ganymede and Callisto are similar in size and are made of a similar mixture of ice and rock, but data from the Galileo and Voyager spacecraft show that they look different at the surface and on the inside. Just like Earth and Venus, Ganymede and Callisto are twins, and understanding how they were born the same and grew up to be so different is of tremendous interest to planetary scientists.

Ganymede and Callisto’s evolutionary paths diverged about 3.8 billion years ago during the Late Heavy Bombardment, the phase in lunar history dominated by large impact events. Impacts during this period melted Ganymede so thoroughly and deeply that the heat could not be quickly removed. All of Ganymede’s rock sank to its center the same way that all the chocolate chips sink to the bottom of a melted carton of ice cream. Callisto received fewer impacts at lower velocities and avoided complete melting. Ganymede is closer to Jupiter and therefore is hit by twice as many icy impactors as Callisto, and the impactors hitting Ganymede have a higher average velocity.

Image Credit: NOAA/GSD

(Source: swri.org)

The planetary nebula Abell 33 captured using ESO’s Very Large Telescope

Astronomers using ESO’s Very Large Telescope in Chile have captured this eye-catching image of planetary nebula Abell 33. Created when an aging star blew off its outer layers, this beautiful blue bubble is, by chance, aligned with a foreground star, and bears an uncanny resemblance to a diamond engagement ring. This cosmic gem is unusually symmetric, appearing to be almost perfectly circular on the sky.

Credit: ESO

The planetary nebula Abell 33 captured using ESO’s Very Large Telescope

Astronomers using ESO’s Very Large Telescope in Chile have captured this eye-catching image of planetary nebula Abell 33. Created when an aging star blew off its outer layers, this beautiful blue bubble is, by chance, aligned with a foreground star, and bears an uncanny resemblance to a diamond engagement ring. This cosmic gem is unusually symmetric, appearing to be almost perfectly circular on the sky.

Credit: ESO


Comet Arend–Roland was discovered on November 8, 1956, by Belgian astronomers Sylvain Arend and Georges Roland on photographic plates. As the eighth comet found in 1956, it was named Arend–Roland 1956h after its discoverers. Because it was the third comet to pass through perihelion during 1957, it was then renamed 1957 III. Finally, it received the standard IAU designation C/1956 R1 (Arend–Roland), with the ‘C/’ indicating it was a non-periodic comet and the R1 showing it was the first comet reported as discovered in the half-month designated by R. The last is equivalent to the period September 1–15.
Astronomer Carl Sagan relates an anecdote on page 80 of his book Cosmos about being on duty in an observatory near Chicago in 1957 when a late night phone call from an inebriated man asked what was the “fuzzy thing” they were seeing in the sky. Sagan told the man it was a comet (Arend–Roland). The man asked what a comet was, and Sagan answered that it was “a snowball, one mile wide”. After a long pause, the man said, quoting Sagan: “Lemme talk to a real ‘shtronomer!”.

Comet Arend–Roland was discovered on November 8, 1956, by Belgian astronomers Sylvain Arend and Georges Roland on photographic plates. As the eighth comet found in 1956, it was named Arend–Roland 1956h after its discoverers. Because it was the third comet to pass through perihelion during 1957, it was then renamed 1957 III. Finally, it received the standard IAU designation C/1956 R1 (Arend–Roland), with the ‘C/’ indicating it was a non-periodic comet and the R1 showing it was the first comet reported as discovered in the half-month designated by R. The last is equivalent to the period September 1–15.

Astronomer Carl Sagan relates an anecdote on page 80 of his book Cosmos about being on duty in an observatory near Chicago in 1957 when a late night phone call from an inebriated man asked what was the “fuzzy thing” they were seeing in the sky. Sagan told the man it was a comet (Arend–Roland). The man asked what a comet was, and Sagan answered that it was “a snowball, one mile wide”. After a long pause, the man said, quoting Sagan: “Lemme talk to a real ‘shtronomer!”.

The Milky Way above Las Campanas Observatory (LCO)

Image Credit: Tudorica Alexandru

The Milky Way above Las Campanas Observatory (LCO)

Image Credit: Tudorica Alexandru


“Recognize that the very molecules that make up your body, the atoms that construct the molecules, are traceable to the crucibles that were once the centers of high mass stars that exploded their chemically rich guts into the galaxy, enriching pristine gas clouds with the chemistry of life. So that we are all connected to each other biologically, to the earth chemically and to the rest of the universe atomically. That’s kinda cool! That makes me smile and I actually feel quite large at the end of that. It’s not that we are better than the universe, we are part of the universe. We are in the universe and the universe is in us.”
― Neil deGrasse Tyson

Illustration based on a quote by Edward R Harrison. Image Credit: Jacob Schuhle-Lewis

“Recognize that the very molecules that make up your body, the atoms that construct the molecules, are traceable to the crucibles that were once the centers of high mass stars that exploded their chemically rich guts into the galaxy, enriching pristine gas clouds with the chemistry of life. So that we are all connected to each other biologically, to the earth chemically and to the rest of the universe atomically. That’s kinda cool! That makes me smile and I actually feel quite large at the end of that. It’s not that we are better than the universe, we are part of the universe. We are in the universe and the universe is in us.”

Neil deGrasse Tyson

Illustration based on a quote by Edward R Harrison. Image Credit: Jacob Schuhle-Lewis

Spiral galaxy ESO 137-001

This Hubble image shows ESO 137-001, a galaxy located in the southern constellation of Triangulum Australe (The Southern Triangle) — a delicate and beautiful spiral galaxy, but with a secret. The image not only captures the galaxy and its backdrop in stunning detail, but also something more dramatic — intense blue streaks streaming outwards from the galaxy, seen shining brightly in ultraviolet light.
These streaks are actually hot young stars, encased in wispy streams of gas that are being torn away from the galaxy by its surroundings as it moves through space. This violent galactic disrobing is due to a process known as ram pressure stripping — a drag force felt by an object moving through a fluid . The fluid in question here is superheated gas, which lurks at the centres of galaxy clusters.
This image combines NASA/ESA Hubble Space Telescope observations with data from the Chandra X-ray Observatory.

Credit: NASA, ESA, CXC

Spiral galaxy ESO 137-001

This Hubble image shows ESO 137-001, a galaxy located in the southern constellation of Triangulum Australe (The Southern Triangle) — a delicate and beautiful spiral galaxy, but with a secret. The image not only captures the galaxy and its backdrop in stunning detail, but also something more dramatic — intense blue streaks streaming outwards from the galaxy, seen shining brightly in ultraviolet light.

These streaks are actually hot young stars, encased in wispy streams of gas that are being torn away from the galaxy by its surroundings as it moves through space. This violent galactic disrobing is due to a process known as ram pressure stripping — a drag force felt by an object moving through a fluid . The fluid in question here is superheated gas, which lurks at the centres of galaxy clusters.

This image combines NASA/ESA Hubble Space Telescope observations with data from the Chandra X-ray Observatory.

Credit: NASA, ESA, CXC

Fire and Ice

Saturn’s largest and second largest moons, Titan and Rhea, appear to be stacked on top of each other in this true-color scene from NASA’s Cassini spacecraft.

Titan is likely differentiated into several layers with a 3,400-kilometre (2,100 mi) rocky center surrounded by several layers composed of different crystal forms of ice.Its interior may still be hot and there may be a liquid layer consisting of a “magma" composed of water and ammonia between the ice Ih crust and deeper ice layers made of high-pressure forms of ice.

Rhea is an ice-cold body of weak density (1.236 g/cm3), indicating that the moon consists of a rocky nucleus counting only for a third of the mass of Rhea, the rest being mainly some ice-cold water.

Credit: NASA/JPL-Caltech/SSI


While sunspots are relatively cool and quiescent regions on the Sun, the photosphere around them sometimes erupts with outflows of high energy particles in active regions. Most often these eruptions are in the form of loops and sheets called prominences which remain under the control of the intense magnetic fields associated with solar storms. There are other events which in a matter of minutes can release enormous amounts of energy and eject material out into space. Such violent events are called solar flares.

Images credit: TRACE/NASA

While sunspots are relatively cool and quiescent regions on the Sun, the photosphere around them sometimes erupts with outflows of high energy particles in active regions. Most often these eruptions are in the form of loops and sheets called prominences which remain under the control of the intense magnetic fields associated with solar storms. There are other events which in a matter of minutes can release enormous amounts of energy and eject material out into space. Such violent events are called solar flares.

Images credit: TRACE/NASA

Rhea: Saturn’s Mysterious Moon

Rhea, the second largest moon of Saturn, is a dirty snowball of rock and ice. The only moon with an oxygen atmosphere, thin though it may be, Rhea is one of the most heavily cratered satellites in the solar system.

A very faint oxygen atmosphere exists around Rhea, the first direct evidence of an oxygen atmosphere on a body other than Earth. The atmosphere is thin, with oxygen measuring about 5 trillion times less dense than that found on Earth. Oxygen could be released as the surface is irradiated by ions from Saturn’s magnetosphere. The source of the carbon dioxide is less clear, but could be the result of similar irradiation, or from dry ice much like comets.

On March 6, 2008, NASA announced that Rhea may have a tenuous ring system. This would mark the first discovery of rings about a moon. The rings’ existence was inferred by observed changes in the flow of electrons trapped by Saturn’s magnetic field as Cassini passed by Rhea. Dust and debris could extend out to Rhea’s Hill sphere, but were thought to be denser nearer the moon, with three narrow rings of higher density. The case for a ring was strengthened by the subsequent finding of the presence of a set of small ultraviolet-bright spots distributed along Rhea’s equator (interpreted as the impact points of deorbiting ring material).However, when Cassini made targeted observations of the putative ring plane from several angles, no evidence of ring material was found, but there’s still something around Rhea that is causing a strange, symmetrical structure in the charged-particle environment around Saturn’s second-largest moon.

Image credit: NASA/JPL-Caltech/SSI,Gordan Ugarkovic

Plasmoids

A plasmoid is a coherent structure of plasma and magnetic fields. Plasmoids have been proposed to explain natural phenomena such as ball lightning, magnetic bubbles in the magnetosphere, and objects in cometary tails, in the solar wind, in the solar atmosphere, and in the heliospheric current sheet. Plasmoids produced in the laboratory include field-reversed configurations, spheromaks, and in dense plasma focuses.

The word plasmoid was coined in 1956 by Winston H. Bostick (1916-1991) to mean a “plasma-magnetic entity”. Bostick went on to apply his theory of plasmoids to astrophysics phenomena. 

Active regions on the solar surface are often the site of eruptions. These are associated with magnetic fields from the solar interior rising to the surface and gradually expanding into the Sun’s outer atmosphere, the corona, in a process known as magnetic flux emergence.

A group of scientists from the University of St Andrews developed 3D computer models of these phenomena, revealing that the emergence of magnetic flux naturally leads to the formation and expulsion of plasmoids that adopt a twisted tube configuration.

The formation of the plasmoids is due to the motion of plasma in the lower atmosphere of the Sun. These motions bring magnetic fieldlines closer together to reconnect and build a new magnetic flux system (i.e. the plasmoid). Whether the plasmoids are ‘failed’ or ‘successful’ (i.e. they erupt into space) depends on the level of interaction between the new emerging field and the old, pre-existing magnetic field in the solar corona.

Credit: Vasilis Archontis

The Submillimeter Array telescope unveils how small cosmic seeds grow into big stars

New images from the Smithsonian’s Submillimeter Array (SMA) telescope provide the most detailed view yet of stellar nurseries within the Snake Nebula. These images offer new insights into how cosmic seeds can grow into massive stars.
Stretching across almost 100 light-years of space, the Snake Nebula is located about 11,700 light-years from Earth in the direction of the constellation Ophiuchus. In images from NASA’s Spitzer Space Telescope, it appears as a sinuous dark tendril against the starry background. It was targeted because it shows the potential to form many massive stars (stars heavier than eight times our Sun).
Full Article

Image Credit: Spitzer/GLIMPSE/MIPS, Herschel/HiGal, Ke Wang (ESO)

The Submillimeter Array telescope unveils how small cosmic seeds grow into big stars

New images from the Smithsonian’s Submillimeter Array (SMA) telescope provide the most detailed view yet of stellar nurseries within the Snake Nebula. These images offer new insights into how cosmic seeds can grow into massive stars.

Stretching across almost 100 light-years of space, the Snake Nebula is located about 11,700 light-years from Earth in the direction of the constellation Ophiuchus. In images from NASA’s Spitzer Space Telescope, it appears as a sinuous dark tendril against the starry background. It was targeted because it shows the potential to form many massive stars (stars heavier than eight times our Sun).

Full Article

Image Credit: Spitzer/GLIMPSE/MIPS, Herschel/HiGal, Ke Wang (ESO)

A Change Of Perspective

This animation was composed of 6 color frames taken on February 3rd, 2007 over the course of 2 hours by Cassini’s wide angle camera.
Cassini was moving from below the ring plane towards the ring plane crossing and moving away from the planet at the same time.
At the start of the sequence the phase angle was 16.8 deg and distance was 1.070 mil km. This increased to 17.5 deg and 1.080 mil km at the end, respectively. During that period Saturn can be seen rotating, notice particularly the streaky clouds just below the ring shadows.

Image Credit: Gordan Ugarkovic

A Change Of Perspective

This animation was composed of 6 color frames taken on February 3rd, 2007 over the course of 2 hours by Cassini’s wide angle camera.

Cassini was moving from below the ring plane towards the ring plane crossing and moving away from the planet at the same time.

At the start of the sequence the phase angle was 16.8 deg and distance was 1.070 mil km. This increased to 17.5 deg and 1.080 mil km at the end, respectively. During that period Saturn can be seen rotating, notice particularly the streaky clouds just below the ring shadows.

Image Credit: Gordan Ugarkovic

Enceladus and Saturn

Cassini Narrow Angle camera (NAC) clear filter frame colorized to approximate the appearance of Saturn’s limb and emphasize Enceladus’ grayish color in contrast. 

Image credit: Gordan Ugarkovic

Enceladus and Saturn

Cassini Narrow Angle camera (NAC) clear filter frame colorized to approximate the appearance of Saturn’s limb and emphasize Enceladus’ grayish color in contrast.

Image credit: Gordan Ugarkovic


Neptune is the eighth planet from the Sun and the smallest of the gas giants. Neptune was the first planet found by mathematical prediction after unexpected changes in the orbit of Uranus were observed. Neptune is named after the Roman god of the sea.
The blue coloring is the result of methane in the atmosphere, though the exact reason for the vividness of the blue is still unknown. The winds that whip around Neptune are on average nine times faster than those on Earth and are believed to be the strongest winds in the solar system.
Storms much like the Great Red Spot on Jupiter have been seen on Neptune. Unlike the Great Red Spot, which has been observed for over 300 years, the storms on Neptune seem to come and go. In 1986 the Voyager 2 discovered the Great Dark Spot, a storm in the Southern Hemisphere. However, later images from the Hubble Space Telescope show that the Great Dark Spot no longer exists and that a new storm formed in the Northern Hemisphere. Also, there is a group of white clouds referred to as The Scooter which races around the planet every 16 hours. The Scooter is thought to be a plume from lower in the atmosphere, though its true origin is unknown.

Image Credit: Steve Albers, NOAA/GSD

Neptune is the eighth planet from the Sun and the smallest of the gas giants. Neptune was the first planet found by mathematical prediction after unexpected changes in the orbit of Uranus were observed. Neptune is named after the Roman god of the sea.

The blue coloring is the result of methane in the atmosphere, though the exact reason for the vividness of the blue is still unknown. The winds that whip around Neptune are on average nine times faster than those on Earth and are believed to be the strongest winds in the solar system.

Storms much like the Great Red Spot on Jupiter have been seen on Neptune. Unlike the Great Red Spot, which has been observed for over 300 years, the storms on Neptune seem to come and go. In 1986 the Voyager 2 discovered the Great Dark Spot, a storm in the Southern Hemisphere. However, later images from the Hubble Space Telescope show that the Great Dark Spot no longer exists and that a new storm formed in the Northern Hemisphere. Also, there is a group of white clouds referred to as The Scooter which races around the planet every 16 hours. The Scooter is thought to be a plume from lower in the atmosphere, though its true origin is unknown.

Image Credit: Steve Albers, NOAA/GSD