2020 August 30
NGC 6357: Cathedral to Massive Stars
Image Credit: NASA, ESA and Jesús Maíz Apellániz (IAA, Spain); Acknowledgement: Davide De Martin (ESA/Hubble)
How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known. This star is the brightest object located just above the gas front in the featured image. Close inspection of images taken with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the bottom of the image, stars are still forming in the associated emission nebula NGC 6357. Appearing perhaps like a Gothic cathedral, energetic stars near the center appear to be breaking out and illuminating a spectacular cocoon.
NGC 6357: Cathedral to Massive Stars
Image Credit: NASA, ESA and Jesús Maíz Apellániz (IAA, Spain); Acknowledgement: Davide De Martin (ESA/Hubble)
How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known. This star is the brightest object located just above the gas front in the featured image. Close inspection of images taken with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the bottom of the image, stars are still forming in the associated emission nebula NGC 6357. Appearing perhaps like a Gothic cathedral, energetic stars near the center appear to be breaking out and illuminating a spectacular cocoon.
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2020 August 31
SS 433: Binary Star Micro-Quasar
Animation Credit: DESY, Science Communication Lab
SS 433 is one of the most exotic star systems known. Its unremarkable name stems from its inclusion in a catalog of Milky Way stars which emit radiation characteristic of atomic hydrogen. Its remarkable behavior stems from a compact object, a black hole or neutron star, which has produced an accretion disk with jets. Because the disk and jets from SS 433 resemble those surrounding supermassive black holes in the centers of distant galaxies, SS 433 is considered a micro-quasar. As illustrated in the animated featured video based on observational data, a massive, hot, normal star is locked in orbit with the compact object. As the video starts, material is shown being gravitationally ripped from the normal star and falling onto an accretion disk. The central star also blasts out jets of ionized gas in opposite directions – each at about 1/4 the speed of light. The video then pans out to show a top view of the precessing jets producing an expanding spiral. From even greater distances, the dissipating jets are then visualized near the heart of supernova remnant W50. Two years ago, SS 433 was unexpectedly found by the HAWC detector array in Mexico to emit unusually high energy (TeV-range) gamma-rays. Surprises continue, as a recent analysis of archival data taken by NASA's Fermi satellite find a gamma-ray source -- separated from the central stars as shown -- that pulses in gamma-rays with a period of 162 days – the same as SS 433's jet precession period – for reasons yet unknown.
SS 433: Binary Star Micro-Quasar
Animation Credit: DESY, Science Communication Lab
SS 433 is one of the most exotic star systems known. Its unremarkable name stems from its inclusion in a catalog of Milky Way stars which emit radiation characteristic of atomic hydrogen. Its remarkable behavior stems from a compact object, a black hole or neutron star, which has produced an accretion disk with jets. Because the disk and jets from SS 433 resemble those surrounding supermassive black holes in the centers of distant galaxies, SS 433 is considered a micro-quasar. As illustrated in the animated featured video based on observational data, a massive, hot, normal star is locked in orbit with the compact object. As the video starts, material is shown being gravitationally ripped from the normal star and falling onto an accretion disk. The central star also blasts out jets of ionized gas in opposite directions – each at about 1/4 the speed of light. The video then pans out to show a top view of the precessing jets producing an expanding spiral. From even greater distances, the dissipating jets are then visualized near the heart of supernova remnant W50. Two years ago, SS 433 was unexpectedly found by the HAWC detector array in Mexico to emit unusually high energy (TeV-range) gamma-rays. Surprises continue, as a recent analysis of archival data taken by NASA's Fermi satellite find a gamma-ray source -- separated from the central stars as shown -- that pulses in gamma-rays with a period of 162 days – the same as SS 433's jet precession period – for reasons yet unknown.
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2020 September 1
Salt Water Remnants on Ceres
Video Credit: Dawn Mission, NASA, JPL-Caltech, UCLA, MPS/DLR/IDA
Does Ceres have underground pockets of water? Ceres, the largest asteroid in the asteroid belt, was thought to be composed of rock and ice. At the same time, Ceres was known to have unusual bright spots on its surface. These bright spots were clearly imaged during Dawn's exciting approach in 2015. Analyses of Dawn images and spectra indicated that the bright spots arise from the residue of highly-reflective salt water that used to exist on Ceres' surface but evaporated. Recent analysis indicates that some of this water may have originated from deep inside the dwarf planet, indicating Ceres to be a kindred spirit with several Solar System moons, also thought to harbor deep water pockets. The featured video shows in false-color pink the bright evaporated brine named Cerealia Facula in Occator Crater. In 2018, the mission-successful but fuel-depleted Dawn spacecraft was placed in a distant parking orbit, keeping it away from the Ceres' surface for at least 20 years to avoid interfering with any life that might there exist.
Salt Water Remnants on Ceres
Video Credit: Dawn Mission, NASA, JPL-Caltech, UCLA, MPS/DLR/IDA
Does Ceres have underground pockets of water? Ceres, the largest asteroid in the asteroid belt, was thought to be composed of rock and ice. At the same time, Ceres was known to have unusual bright spots on its surface. These bright spots were clearly imaged during Dawn's exciting approach in 2015. Analyses of Dawn images and spectra indicated that the bright spots arise from the residue of highly-reflective salt water that used to exist on Ceres' surface but evaporated. Recent analysis indicates that some of this water may have originated from deep inside the dwarf planet, indicating Ceres to be a kindred spirit with several Solar System moons, also thought to harbor deep water pockets. The featured video shows in false-color pink the bright evaporated brine named Cerealia Facula in Occator Crater. In 2018, the mission-successful but fuel-depleted Dawn spacecraft was placed in a distant parking orbit, keeping it away from the Ceres' surface for at least 20 years to avoid interfering with any life that might there exist.
2020 September 2
Jupiter and the Moons
Image Credit & Copyright: Robert Fedez
How many moons do you see? Many people would say one, referring to the Earth's Moon, prominent on the lower left. But take a closer look at the object on the upper right. That seeming-star is actually the planet Jupiter, and your closer look might reveal that it is not alone – it is surrounded by some of its largest moons. From left to right these Galilean Moons are Io, Ganymende, Europa and Callisto. These moons orbit the Jovian world just like the planets of our Solar System orbit the Sun, in a line when seen from the side. The featured single shot was captured from Cancun, Mexico last week as Luna, in its orbit around the Earth, glided past the distant planet. Even better views of Jupiter are currently being captured by NASA's Juno spacecraft, now in a looping orbit around the Solar System's largest planet. Earth's Moon will continue to pass nearly in front of both Jupiter and Saturn once a month (moon-th) as the two giant planets approach their own great conjunction in December.
Jupiter and the Moons
Image Credit & Copyright: Robert Fedez
How many moons do you see? Many people would say one, referring to the Earth's Moon, prominent on the lower left. But take a closer look at the object on the upper right. That seeming-star is actually the planet Jupiter, and your closer look might reveal that it is not alone – it is surrounded by some of its largest moons. From left to right these Galilean Moons are Io, Ganymende, Europa and Callisto. These moons orbit the Jovian world just like the planets of our Solar System orbit the Sun, in a line when seen from the side. The featured single shot was captured from Cancun, Mexico last week as Luna, in its orbit around the Earth, glided past the distant planet. Even better views of Jupiter are currently being captured by NASA's Juno spacecraft, now in a looping orbit around the Solar System's largest planet. Earth's Moon will continue to pass nearly in front of both Jupiter and Saturn once a month (moon-th) as the two giant planets approach their own great conjunction in December.
2020 September 3
A Halo for Andromeda
Digital Illustration Credit: NASA, ESA, J. DePasquale and E. Wheatley (STScI) and Z. Levay
M31, the Andromeda Galaxy, is the closest large spiral galaxy to our Milky Way. Some 2.5 million light-years distant it shines in Earth's night sky as a small, faint, elongated cloud just visible to the unaided eye. Invisible to the eye though, its enormous halo of hot ionized gas is represented in purplish hues for this digital illustration of our neighboring galaxy above rocky terrain. Mapped by Hubble Space Telescope observations of the absorption of ultraviolet light against distant quasars, the extent and make-up of Andromeda's gaseous halo has been recently determined by the AMIGA project. A reservoir of material for future star formation, Andromeda's halo of diffuse plasma was measured to extend around 1.3 million light-years or more from the galaxy. That's about half way to the Milky Way, likely putting it in contact with the diffuse gaseous halo of our own galaxy.
A Halo for Andromeda
Digital Illustration Credit: NASA, ESA, J. DePasquale and E. Wheatley (STScI) and Z. Levay
M31, the Andromeda Galaxy, is the closest large spiral galaxy to our Milky Way. Some 2.5 million light-years distant it shines in Earth's night sky as a small, faint, elongated cloud just visible to the unaided eye. Invisible to the eye though, its enormous halo of hot ionized gas is represented in purplish hues for this digital illustration of our neighboring galaxy above rocky terrain. Mapped by Hubble Space Telescope observations of the absorption of ultraviolet light against distant quasars, the extent and make-up of Andromeda's gaseous halo has been recently determined by the AMIGA project. A reservoir of material for future star formation, Andromeda's halo of diffuse plasma was measured to extend around 1.3 million light-years or more from the galaxy. That's about half way to the Milky Way, likely putting it in contact with the diffuse gaseous halo of our own galaxy.
2020 September 4
The Wizard Nebula
Image Credit & Copyright: Andrew Klinger
Open star cluster NGC 7380 is still embedded in its natal cloud of interstellar gas and dust popularly known as the Wizard Nebula. Seen on the left, with foreground and background stars along the plane of our Milky Way galaxy it lies some 8,000 light-years distant, toward the constellation Cepheus. In apparent size on the sky, a full moon would cover the 4 million year young cluster and associated nebula, normally much too faint to be seen by eye. Made with telescope and camera firmly planted on Earth, the image reveals multi light-year sized shapes and structures of cosmic gas and dust within the Wizard though, in a color palette made popular in Hubble Space Telescope images. Recorded with narrowband filters, the visible wavelength light from the nebula's hydrogen, oxygen, and sulfur atoms is transformed into green, blue, and red colors in the final digital composite.
The Wizard Nebula
Image Credit & Copyright: Andrew Klinger
Open star cluster NGC 7380 is still embedded in its natal cloud of interstellar gas and dust popularly known as the Wizard Nebula. Seen on the left, with foreground and background stars along the plane of our Milky Way galaxy it lies some 8,000 light-years distant, toward the constellation Cepheus. In apparent size on the sky, a full moon would cover the 4 million year young cluster and associated nebula, normally much too faint to be seen by eye. Made with telescope and camera firmly planted on Earth, the image reveals multi light-year sized shapes and structures of cosmic gas and dust within the Wizard though, in a color palette made popular in Hubble Space Telescope images. Recorded with narrowband filters, the visible wavelength light from the nebula's hydrogen, oxygen, and sulfur atoms is transformed into green, blue, and red colors in the final digital composite.
2020 September 5
A Falcon 9 Moon
Image Credit & Copyright: Katie Darby
Illuminating planet Earth's night, full moons can have many names. This year the last full moon of northern hemisphere summer was on September 2, known to some as the Full Corn Moon. A few days earlier on August 30 this almost full moon rose just before sunset though, shining through cloudy skies over Cape Canaveral Air Force Station on Florida's Space Coast. A well-timed snapshot caught the glare of rocket engines firing below the lunar disk, a Falcon 9 rocket's first stage successfully returning to Cape Canaveral's landing zone 1. About 9 minutes earlier, the same SpaceX Falcon 9 rocket had launched the SAOCOM 1B satellite toward polar orbit. The fourth launch for this reusable Falcon 9 first stage, it was the first launch to a polar orbit from Cape Canaveral since 1969.
A Falcon 9 Moon
Image Credit & Copyright: Katie Darby
Illuminating planet Earth's night, full moons can have many names. This year the last full moon of northern hemisphere summer was on September 2, known to some as the Full Corn Moon. A few days earlier on August 30 this almost full moon rose just before sunset though, shining through cloudy skies over Cape Canaveral Air Force Station on Florida's Space Coast. A well-timed snapshot caught the glare of rocket engines firing below the lunar disk, a Falcon 9 rocket's first stage successfully returning to Cape Canaveral's landing zone 1. About 9 minutes earlier, the same SpaceX Falcon 9 rocket had launched the SAOCOM 1B satellite toward polar orbit. The fourth launch for this reusable Falcon 9 first stage, it was the first launch to a polar orbit from Cape Canaveral since 1969.
2020 September 6
M1: The Crab Nebula from Hubble
Image Credit: NASA, ESA, Hubble, J. Hester, A. Loll (ASU)
This is the mess that is left when a star explodes. The Crab Nebula, the result of a supernova seen in 1054 AD, is filled with mysterious filaments. The filaments are not only tremendously complex, but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion. The featured image, taken by the Hubble Space Telescope, is presentedi in three colors chosen for scientific interest. The Crab Nebula spans about 10 light-years. In the nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second.
M1: The Crab Nebula from Hubble
Image Credit: NASA, ESA, Hubble, J. Hester, A. Loll (ASU)
This is the mess that is left when a star explodes. The Crab Nebula, the result of a supernova seen in 1054 AD, is filled with mysterious filaments. The filaments are not only tremendously complex, but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion. The featured image, taken by the Hubble Space Telescope, is presentedi in three colors chosen for scientific interest. The Crab Nebula spans about 10 light-years. In the nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second.
2020 September 7
The Milky Way over St Michael's Mount
Image Credit: Simon R. Hudson
Where do land and sky converge? On every horizon -- but in this case the path on the ground leads to St Michael's Mount (Cornish: Karrek Loos yn Koos), a small historic island in Cornwall, England. The Mount is usually surrounded by shallow water, but at low tide is spanned by a human-constructed causeway. The path on the sky, actually the central band of our Milky Way Galaxy, also appears to lead to St Michael's Mount, but really lies far in the distance. The red nebula in the Milky Way, just above the castle, is the Lagoon Nebula, while bright Jupiter shines to the left, and a luminous meteor flashes to the right. The foreground and background images of this featured composite were taken on the same July night and from the same location. Although meteors are fleeting and the Milky Way disk shifts in the night as the Earth turns, Jupiter will remain prominent in the sunset sky into December.
The Milky Way over St Michael's Mount
Image Credit: Simon R. Hudson
Where do land and sky converge? On every horizon -- but in this case the path on the ground leads to St Michael's Mount (Cornish: Karrek Loos yn Koos), a small historic island in Cornwall, England. The Mount is usually surrounded by shallow water, but at low tide is spanned by a human-constructed causeway. The path on the sky, actually the central band of our Milky Way Galaxy, also appears to lead to St Michael's Mount, but really lies far in the distance. The red nebula in the Milky Way, just above the castle, is the Lagoon Nebula, while bright Jupiter shines to the left, and a luminous meteor flashes to the right. The foreground and background images of this featured composite were taken on the same July night and from the same location. Although meteors are fleeting and the Milky Way disk shifts in the night as the Earth turns, Jupiter will remain prominent in the sunset sky into December.
2020 September 8
GW190521: Unexpected Black Holes Collide
Illustration Credit: Raúl Rubio (Virgo Valencia Group, The Virgo Collaboration)
How do black holes like this form? The two black holes that spiraled together to produce the gravitational wave event GW190521 were not only the most massive black holes ever seen by LIGO and VIRGO so far, their masses -- 66 and 85 solar masses -- were unprecedented and unexpected. Lower mass black holes, below about 65 solar masses are known to form in supernova explosions. Conversely, higher mass black holes, above about 135 solar masses, are thought to be created by very massive stars imploding after they use up their weight-bearing nuclear-fusion-producing elements. How such intermediate mass black holes came to exist is yet unknown, although one hypothesis holds that they result from consecutive collisions of stars and black holes in dense star clusters. Featured is an illustration of the black holes just before collision, annotated with arrows indicating their spin axes. In the illustration, the spiral waves indicate the production of gravitational radiation, while the surrounding stars highlight the possibility that the merger occurred in a star cluster. Seen last year but emanating from an epoch when the universe was only about half its present age (z ~ 0.8), black hole merger GW190521 is the farthest yet detected, to within measurement errors.
GW190521: Unexpected Black Holes Collide
Illustration Credit: Raúl Rubio (Virgo Valencia Group, The Virgo Collaboration)
How do black holes like this form? The two black holes that spiraled together to produce the gravitational wave event GW190521 were not only the most massive black holes ever seen by LIGO and VIRGO so far, their masses -- 66 and 85 solar masses -- were unprecedented and unexpected. Lower mass black holes, below about 65 solar masses are known to form in supernova explosions. Conversely, higher mass black holes, above about 135 solar masses, are thought to be created by very massive stars imploding after they use up their weight-bearing nuclear-fusion-producing elements. How such intermediate mass black holes came to exist is yet unknown, although one hypothesis holds that they result from consecutive collisions of stars and black holes in dense star clusters. Featured is an illustration of the black holes just before collision, annotated with arrows indicating their spin axes. In the illustration, the spiral waves indicate the production of gravitational radiation, while the surrounding stars highlight the possibility that the merger occurred in a star cluster. Seen last year but emanating from an epoch when the universe was only about half its present age (z ~ 0.8), black hole merger GW190521 is the farthest yet detected, to within measurement errors.
2020 September 9
Pleiades: The Seven Sisters Star Cluster
Image Credit & Copyright: Raul Villaverde Fraile
Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as large and clear as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city. With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The featured exposure covers a sky area several times the size of the full moon. Also known as the Seven Sisters and M45, the Pleiades lies about 400 light years away toward the constellation of the Bull (Taurus). A common legend with a modern twist is that one of the brighter stars faded since the cluster was named, leaving only six of the sister stars visible to the unaided eye. The actual number of Pleiades stars visible, however, may be more or less than seven, depending on the darkness of the surrounding sky and the clarity of the observer's eyesight.
Pleiades: The Seven Sisters Star Cluster
Image Credit & Copyright: Raul Villaverde Fraile
Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as large and clear as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city. With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The featured exposure covers a sky area several times the size of the full moon. Also known as the Seven Sisters and M45, the Pleiades lies about 400 light years away toward the constellation of the Bull (Taurus). A common legend with a modern twist is that one of the brighter stars faded since the cluster was named, leaving only six of the sister stars visible to the unaided eye. The actual number of Pleiades stars visible, however, may be more or less than seven, depending on the darkness of the surrounding sky and the clarity of the observer's eyesight.
2020 September 10
Jupiter's Swimming Storm
Image Credit & Copyright: Andy Casely
A bright storm head with a long turbulent wake swims across Jupiter in these sharp telescopic images of the Solar System's ruling gas giant. Captured on August 26, 28, and September 1 (left to right) the storm approximately doubles in length during that period. Stretching along the jetstream of the planet's North Temperate Belt it travels eastward in successive frames, passing the Great Red Spot and whitish Oval BA, famous storms in Jupiter's southern hemisphere. Galilean moons Callisto and Io are caught in the middle frame. In fact, telescopic skygazers following Jupiter in planet Earth's night have reported dramatic fast moving storm outbreaks over the past few weeks in Jupiter's North Temperate Belt.
Jupiter's Swimming Storm
Image Credit & Copyright: Andy Casely
A bright storm head with a long turbulent wake swims across Jupiter in these sharp telescopic images of the Solar System's ruling gas giant. Captured on August 26, 28, and September 1 (left to right) the storm approximately doubles in length during that period. Stretching along the jetstream of the planet's North Temperate Belt it travels eastward in successive frames, passing the Great Red Spot and whitish Oval BA, famous storms in Jupiter's southern hemisphere. Galilean moons Callisto and Io are caught in the middle frame. In fact, telescopic skygazers following Jupiter in planet Earth's night have reported dramatic fast moving storm outbreaks over the past few weeks in Jupiter's North Temperate Belt.
2020 September 11
The Reappearance of Mars
Image Credit & Copyright: David Duarte and Romualdo Caldas
Mars reappears just beyond the Moon's dark limb in this stack of sharp video frames captured on September 6. Of course to reappear it had to disappear in the first place. It did that over an hour earlier when the sunlit southern edge of the waning gibbous Moon passed in front of the Red Planet as seen from Maceio, Brazil. The lunar occultation came as the Moon was near apogee, about 400,000 kilometers away. Mars was almost 180 times more distant. It was the fourth lunar occultation of Mars visible from planet Earth in 2020. Visible from some southern latitudes, the fifth lunar occultation of Mars in 2020 will take place on October 3 when the Moon and Mars are both nearly opposite the Sun in planet Earth's sky.
The Reappearance of Mars
Image Credit & Copyright: David Duarte and Romualdo Caldas
Mars reappears just beyond the Moon's dark limb in this stack of sharp video frames captured on September 6. Of course to reappear it had to disappear in the first place. It did that over an hour earlier when the sunlit southern edge of the waning gibbous Moon passed in front of the Red Planet as seen from Maceio, Brazil. The lunar occultation came as the Moon was near apogee, about 400,000 kilometers away. Mars was almost 180 times more distant. It was the fourth lunar occultation of Mars visible from planet Earth in 2020. Visible from some southern latitudes, the fifth lunar occultation of Mars in 2020 will take place on October 3 when the Moon and Mars are both nearly opposite the Sun in planet Earth's sky.
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2020 September 12
A Thousand Meteors
Video Credit & Copyright: Greg Priestley
Over a thousand meteors flash through the night in this intriguing timelapse video. Starting in April 2019 the individual video frames were selected from 372 relatively clear nights of imaging from an automated wide-field observatory in rural New South Wales Australia. Arranged by local sidereal time, a timekeeping system that uses the positions of stars to measure Earth's rotation, the frames follow the full annual progression of constellations through the wide field of view seen from 33 degrees south latitude. They capture a diverse array of meteors including sporadic meteors, bright fireballs, and shower meteors (plus a lightning sprite), during the period. All frames were processed consistently and so show real variations in the local sky conditions.
A Thousand Meteors
Video Credit & Copyright: Greg Priestley
Over a thousand meteors flash through the night in this intriguing timelapse video. Starting in April 2019 the individual video frames were selected from 372 relatively clear nights of imaging from an automated wide-field observatory in rural New South Wales Australia. Arranged by local sidereal time, a timekeeping system that uses the positions of stars to measure Earth's rotation, the frames follow the full annual progression of constellations through the wide field of view seen from 33 degrees south latitude. They capture a diverse array of meteors including sporadic meteors, bright fireballs, and shower meteors (plus a lightning sprite), during the period. All frames were processed consistently and so show real variations in the local sky conditions.
2020 September 13
M2-9: Wings of a Butterfly Nebula
Image Credit: Hubble Legacy Archive, NASA, ESA - Processing: Judy Schmidt
Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and M2-9 pictured here, the stars transform themselves from normal stars to white dwarfs by casting off their outer gaseous envelopes. The expended gas frequently forms an impressive display called a planetary nebula that fades gradually over thousands of years. M2-9, a butterfly planetary nebula 2100 light-years away shown in representative colors, has wings that tell a strange but incomplete tale. In the center, two stars orbit inside a gaseous disk 10 times the orbit of Pluto. The expelled envelope of the dying star breaks out from the disk creating the bipolar appearance. Much remains unknown about the physical processes that cause and shape planetary nebulae.
M2-9: Wings of a Butterfly Nebula
Image Credit: Hubble Legacy Archive, NASA, ESA - Processing: Judy Schmidt
Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and M2-9 pictured here, the stars transform themselves from normal stars to white dwarfs by casting off their outer gaseous envelopes. The expended gas frequently forms an impressive display called a planetary nebula that fades gradually over thousands of years. M2-9, a butterfly planetary nebula 2100 light-years away shown in representative colors, has wings that tell a strange but incomplete tale. In the center, two stars orbit inside a gaseous disk 10 times the orbit of Pluto. The expelled envelope of the dying star breaks out from the disk creating the bipolar appearance. Much remains unknown about the physical processes that cause and shape planetary nebulae.
2020 September 14
Corn Moon Rising
Image Credit & Copyright: Zarcos Palma
A rising moon can be a dramatic sight. A rising Full Corn Moon was captured early this month in time-lapse with a telephoto lens from nearly 30 kilometers away -- making Earth's ascending half-degree companion appear unusually impressive. The image was captured from Portugal, although much of the foreground -- including lights from the village of Puebla de Guzmán -- is in Spain. A Full Corn Moon is the name attributed to a full moon at this time of year by cultures of some northern indigenous peoples of the Americas, as it coincides with the ripening of corn. Note that the Moon does not appear larger when it is nearer the horizon -- its seemingly larger size there is only an illusion. The next full moon -- occurring at the beginning of next month -- will be known as the Full Harvest Moon as it occurs nearest in time to the northern autumnal equinox and the northern field harvests.
Corn Moon Rising
Image Credit & Copyright: Zarcos Palma
A rising moon can be a dramatic sight. A rising Full Corn Moon was captured early this month in time-lapse with a telephoto lens from nearly 30 kilometers away -- making Earth's ascending half-degree companion appear unusually impressive. The image was captured from Portugal, although much of the foreground -- including lights from the village of Puebla de Guzmán -- is in Spain. A Full Corn Moon is the name attributed to a full moon at this time of year by cultures of some northern indigenous peoples of the Americas, as it coincides with the ripening of corn. Note that the Moon does not appear larger when it is nearer the horizon -- its seemingly larger size there is only an illusion. The next full moon -- occurring at the beginning of next month -- will be known as the Full Harvest Moon as it occurs nearest in time to the northern autumnal equinox and the northern field harvests.
2020 September 15
Biomarker Phosphine Discovered in the Atmosphere of Venus
Image Credit: ISAS, JAXA, Akatsuki; Processing: Meli thev
Could there be life floating in the atmosphere of Venus? Although Earth's planetary neighbor has a surface considered too extreme for any known lifeform, Venus' upper atmosphere may be sufficiently mild for tiny airborne microbes. This usually disfavored prospect took an unexpected upturn yesterday with the announcement of the discovery of Venusian phosphine. The chemical phosphine (PH3) is a considered a biomarker because it seems so hard to create from routine chemical processes thought to occur on or around a rocky world such as Venus -- but it is known to be created by microbial life on Earth. The featured image of Venus and its thick clouds was taken in two bands of ultraviolet light by the Venus-orbing Akatsuki, a Japanese robotic satellite that has been orbiting the cloud-shrouded world since 2015. The phosphine finding, if confirmed, may set off renewed interest in searching for other indications of life floating high in the atmosphere of our Solar System's second planet out from the Sun.
Biomarker Phosphine Discovered in the Atmosphere of Venus
Image Credit: ISAS, JAXA, Akatsuki; Processing: Meli thev
Could there be life floating in the atmosphere of Venus? Although Earth's planetary neighbor has a surface considered too extreme for any known lifeform, Venus' upper atmosphere may be sufficiently mild for tiny airborne microbes. This usually disfavored prospect took an unexpected upturn yesterday with the announcement of the discovery of Venusian phosphine. The chemical phosphine (PH3) is a considered a biomarker because it seems so hard to create from routine chemical processes thought to occur on or around a rocky world such as Venus -- but it is known to be created by microbial life on Earth. The featured image of Venus and its thick clouds was taken in two bands of ultraviolet light by the Venus-orbing Akatsuki, a Japanese robotic satellite that has been orbiting the cloud-shrouded world since 2015. The phosphine finding, if confirmed, may set off renewed interest in searching for other indications of life floating high in the atmosphere of our Solar System's second planet out from the Sun.
2020 September 16
Gravel Ejected from Asteroid Bennu
Image Credit: NASA's GSFC, U. Arizona, OSIRIS-REx Lockheed Martin
Why does asteroid Bennu eject gravel into space? No one is sure. The discovery, occurring during several episodes by NASA's visiting OSIRIS-REx spacecraft, was unexpected. Leading ejection hypotheses include impacts by Sun-orbiting meteoroids, sudden thermal fractures of internal structures, and the sudden release of a water vapor jet. The featured two-image composite shows an ejection event that occurred in early 2019, with sun-reflecting ejecta seen on the right. Data and simulations show that large gravel typically falls right back to the rotating 500-meter asteroid, while smaller rocks skip around the surface, and the smallest rocks completely escape the low gravity of the Earth approaching, diamond-shaped asteroid. Jets and surface ejection events were thought to be predominantly the domain of comets, responsible for their tails, comas, and later meteor showers on Earth. Robotic OSIRIS-REx arrived at 101955 Bennu in late 2018, and is planned to touchdown to collect a surface sample in October 2020. If all goes well, this sample will then be returned to Earth for a detailed analysis during 2023. Bennu was chosen as the destination for OSIRIS-REx in part because its surface shows potential to reveal organic compounds from the early days of our Solar System, compounds that could have been the building blocks for life on Earth.
Gravel Ejected from Asteroid Bennu
Image Credit: NASA's GSFC, U. Arizona, OSIRIS-REx Lockheed Martin
Why does asteroid Bennu eject gravel into space? No one is sure. The discovery, occurring during several episodes by NASA's visiting OSIRIS-REx spacecraft, was unexpected. Leading ejection hypotheses include impacts by Sun-orbiting meteoroids, sudden thermal fractures of internal structures, and the sudden release of a water vapor jet. The featured two-image composite shows an ejection event that occurred in early 2019, with sun-reflecting ejecta seen on the right. Data and simulations show that large gravel typically falls right back to the rotating 500-meter asteroid, while smaller rocks skip around the surface, and the smallest rocks completely escape the low gravity of the Earth approaching, diamond-shaped asteroid. Jets and surface ejection events were thought to be predominantly the domain of comets, responsible for their tails, comas, and later meteor showers on Earth. Robotic OSIRIS-REx arrived at 101955 Bennu in late 2018, and is planned to touchdown to collect a surface sample in October 2020. If all goes well, this sample will then be returned to Earth for a detailed analysis during 2023. Bennu was chosen as the destination for OSIRIS-REx in part because its surface shows potential to reveal organic compounds from the early days of our Solar System, compounds that could have been the building blocks for life on Earth.
2020 September 17
Solar Cycle 25 Has Begun
Image Credit: NASA, SDO
The general trend of monthly sunspot data now confirms that the minimum of the approximately 11 year cycle of solar activity occurred in December 2019, marking the start of Solar Cycle 25. That quiet Sun, at minimum activity, appears on the right of this split hemispherical view. In contrast, the left side shows the active Sun at the recognized maximum of Solar Cycle 24, captured in April 2014. The extreme ultraviolet images from the orbiting Solar Dynamics Observatory highlight coronal loops and active regions in the light of highly ionized iron atoms. Driving the space weather around our fair planet, Solar Cycle 24 was a relatively calm one and predictions are that cycle 25 will be calm too. The cycle 25 activity maximum is expected in July 2025. Solar Cycle 1, the first solar cycle determined from early records of sunspot data, is considered to begin with a minimum in February 1755.
Solar Cycle 25 Has Begun
Image Credit: NASA, SDO
The general trend of monthly sunspot data now confirms that the minimum of the approximately 11 year cycle of solar activity occurred in December 2019, marking the start of Solar Cycle 25. That quiet Sun, at minimum activity, appears on the right of this split hemispherical view. In contrast, the left side shows the active Sun at the recognized maximum of Solar Cycle 24, captured in April 2014. The extreme ultraviolet images from the orbiting Solar Dynamics Observatory highlight coronal loops and active regions in the light of highly ionized iron atoms. Driving the space weather around our fair planet, Solar Cycle 24 was a relatively calm one and predictions are that cycle 25 will be calm too. The cycle 25 activity maximum is expected in July 2025. Solar Cycle 1, the first solar cycle determined from early records of sunspot data, is considered to begin with a minimum in February 1755.
2020 September 18
Arp 78: Peculiar Galaxy in Aries
Image Credit & Copyright: Bernard Miller
Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries, some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy. Also known as NGC 772, the island universe is over 100,000 light-years across and sports a single prominent outer spiral arm in this detailed cosmic portrait. Its brightest companion galaxy, compact NGC 770, is toward the upper right of the larger spiral. NGC 770's fuzzy, elliptical appearance contrasts nicely with a spiky foreground Milky Way star in matching yellowish hues. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78's large spiral arm is likely due to gravitational tidal interactions. Faint streams of material seem to connect Arp 78 with its nearby companion galaxies.
Arp 78: Peculiar Galaxy in Aries
Image Credit & Copyright: Bernard Miller
Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries, some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy. Also known as NGC 772, the island universe is over 100,000 light-years across and sports a single prominent outer spiral arm in this detailed cosmic portrait. Its brightest companion galaxy, compact NGC 770, is toward the upper right of the larger spiral. NGC 770's fuzzy, elliptical appearance contrasts nicely with a spiky foreground Milky Way star in matching yellowish hues. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78's large spiral arm is likely due to gravitational tidal interactions. Faint streams of material seem to connect Arp 78 with its nearby companion galaxies.
2020 September 19
Orion in Depth
Illustration Credit & Copyright: Ronald Davison
Orion is a familiar constellation. The apparent positions of its stars in two dimensions create a well-known pattern on the bowl of planet Earth's night sky. Orion may not look quite so familiar in this 3D view though. The illustration reconstructs the relative positions of Orion's bright stars, including data from the Hipparcus catalog of parallax distances. The most distant star shown is Alnilam. The middle one in the projected line of three that make up Orion's belt when viewed from planet Earth, Alnilam is nearly 2,000 light-years away, almost 3 times as far as fellow belt stars Alnitak and Mintaka. Though Rigel and Betelgeuse apparently shine brighter in planet Earth's sky, that makes more distant Alnilam intrinsically (in absolute magnitude) the brightest of the familiar stars in Orion. In the Hipparcus catalog, errors in measured parallaxes for Orion's stars can translate in to distance errors of a 100 light-years or so.
Orion in Depth
Illustration Credit & Copyright: Ronald Davison
Orion is a familiar constellation. The apparent positions of its stars in two dimensions create a well-known pattern on the bowl of planet Earth's night sky. Orion may not look quite so familiar in this 3D view though. The illustration reconstructs the relative positions of Orion's bright stars, including data from the Hipparcus catalog of parallax distances. The most distant star shown is Alnilam. The middle one in the projected line of three that make up Orion's belt when viewed from planet Earth, Alnilam is nearly 2,000 light-years away, almost 3 times as far as fellow belt stars Alnitak and Mintaka. Though Rigel and Betelgeuse apparently shine brighter in planet Earth's sky, that makes more distant Alnilam intrinsically (in absolute magnitude) the brightest of the familiar stars in Orion. In the Hipparcus catalog, errors in measured parallaxes for Orion's stars can translate in to distance errors of a 100 light-years or so.