May 27, 2017

Cygnus X

Cygnus X

Cygnus X hosts many young stellar groupings. The combined outflows and ultraviolet radiation from the region's numerous massive stars have heated and pushed gas away from the clusters, producing cavities of hot, lower-density gas.

In this 8-micron infrared image, ridges of denser gas mark the boundaries of the cavities. Bright spots within these ridges show where stars are forming today.

Image Credit: NASA/IPAC/MSX
Explanation from: https://www.nasa.gov/multimedia/imagegallery/image_feature_2119.html

Veil Nebula

Veil Nebula

The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop (radio source W78, or Sharpless 103), a large but relatively faint supernova remnant. The source supernova exploded circa 3,000 BC to 6,000 BC, and the remnants have since expanded to cover an area roughly 3 degrees in diameter (about 6 times the diameter, or 36 times the area, of the full moon). The distance to the nebula is not precisely known, but Far Ultraviolet Spectroscopic Explorer (FUSE) data supports a distance of about 1,470 light-years.

Image Credit & Copyright: T. A. Rector (U. Alaska), NOAO, AURA, NSF
Explanation from: https://en.wikipedia.org/wiki/Veil_Nebula

Jupiter's Aurora

Jupiter's Aurora

This ultraviolet image of Jupiter was taken with the Hubble Space Telescope Imaging Spectrograph (STIS) on 26 November 1998 and gives a good impression of the observations that Hubble will make in the weeks to come. The bright emissions above the dark blue background are auroral lights, similar to those seen above the Earth's polar regions. The aurorae are curtains of light resulting from high energy electrons following the planet's magnetic field into the upper atmosphere, where collisions with atmospheric atoms and molecules produce the observed light. On Jupiter one can normally see three different types of auroral emissions:

a) a main oval, centred on the magnetic north pole

b) a pattern of more diffuse emissions inside the polar cap and

c) a unique auroral feature showing the 'magnetic footprints' of three of Jupiter's satellites. These 'footprints' can be seen in this image: from Io (along the left-hand limb), from Ganymede (near the centre just below the reference oval) and from Europa (just below and to the right of Ganymede's auroral footprint). These emissions are unlike anything seen on Earth and are produced by electric currents generated at the satellites that then flow along Jupiter's magnetic field, weaving in and out of its upper atmosphere.

This incredibly detailed image was taken on November 26 1998 when Jupiter was at a distance of 700 million km from Earth. The image was taken in UV light at 140 nm.

Image Credit: NASA, ESA & John T. Clarke (Univ. of Michigan)
Explanation from: https://www.spacetelescope.org/images/heic0009a/

Exoplanet HD 189733b

Exoplanet HD 189733b

HD 189733 b is an extrasolar planet approximately 63 light-years away from the Solar System in the constellation of Vulpecula. The planet was discovered orbiting the star HD 189733 A on October 5, 2005, when astronomers in France observed the planet transiting across the face of the star. With a mass 13% higher than that of Jupiter, HD 189733 b orbits its host star once every 2.2 days at an orbital speed of 152.5 kilometres per second (341,000 mph), making it a hot Jupiter with poor prospects for extraterrestrial life. Being the closest transiting hot Jupiter to Earth, HD 189733 b is a subject for extensive atmospheric examination. HD 189733 b was the first extrasolar planet for which a thermal map was constructed, to be detected through polarimetry, to have its overall color determined (deep blue), to have a transit detected in X-ray spectrum and to have carbon dioxide detected in its atmosphere.

In July, 2014, NASA announced finding very dry atmospheres on three exoplanets (HD 189733b, HD 209458b, WASP-12b) orbiting Sun-like stars.

Image Credit: NASA
Explanation from: https://en.wikipedia.org/wiki/HD_189733_b

Spiral Galaxy Messier 81

Spiral Galaxy Messier 81

This beautiful galaxy is tilted at an oblique angle on to our line of sight, giving a "birds-eye view" of the spiral structure. The galaxy is similar to our Milky Way, but our favorable view provides a better picture of the typical architecture of spiral galaxies.

M81 may be undergoing a surge of star formation along the spiral arms due to a close encounter it may have had with its nearby spiral galaxy NGC 3077 and a nearby starburst galaxy (M82) about 300 million years ago.

M81 is one of the brightest galaxies that can be seen from the Earth. It is high in the northern sky in the circumpolar constellation Ursa Major, the Great Bear. At an apparent magnitude of 6.8 it is just at the limit of naked-eye visibility. The galaxy's angular size is about the same as that of the Full Moon.

This image combines data from the Hubble Space Telescope, the Spitzer Space Telescope, and the Galaxy Evolution Explorer (GALEX) missions. The GALEX ultraviolet data were from the far-UV portion of the spectrum (135 to 175 nanometers). The Spitzer infrared data were taken with the IRAC channel 4 detector (8 microns). The Hubble data were taken at the blue portion of the spectrum.

Image Credit: Hubble data: NASA, ESA
Explanation from: http://www.spitzer.caltech.edu/images/2126-sig07-009-Multiwavelength-M81

Planetary Nebula NGC 6210

Planetary Nebula NGC 6210

The NASA/ESA Hubble Space Telescope has taken a striking high resolution image of the curious planetary nebula NGC 6210. Located about 6500 light-years away, in the constellation of Hercules, NGC 6210 was discovered in 1825 by the German astronomer Friedrich Georg Wilhelm Struve. Although in a small telescope it appears only as a tiny disc, it is fairly bright.

NGC 6210 is the last gasp of a star slightly less massive than our Sun at the final stage of its life cycle. The multiple shells of material ejected by the dying star form a superposition of structures with different degrees of symmetry, giving NGC 6210 its odd shape. This sharp image shows the inner region of this planetary nebula in unprecedented detail, where the central star is surrounded by a thin, bluish bubble that reveals a delicate filamentary structure. This bubble is superposed onto an asymmetric, reddish gas formation where holes, filaments and pillars are clearly visible.

The life of a star ends when the fuel available to its thermonuclear engine runs out. The estimated lifetime for a Sun-like star is some ten billion years. When the star is about to expire, it becomes unstable and ejects its outer layers, forming a planetary nebula and leaving behind a tiny, but very hot, remnant, known as white dwarf. This compact object, here visible at the centre of the image, cools down and fades very slowly. Stellar evolution theory predicts that our Sun will experience the same fate as NGC 6210 in about five billion years.

This picture was created from images taken with Hubble’s Wide Field Planetary Camera 2 through three filters: the broadband filter F555W (yellow) and the narrowband filters F656N (ionised hydrogen), F658N (ionised nitrogen) and F502N (ionised oxygen). The exposure times were 80 s, 140 s, 800 s and 700 s respectively and the field of view is only about 28 arcseconds across.

Image Credit: ESA/Hubble and NASA
Explanation from: https://www.spacetelescope.org/images/potw1026a/

May 26, 2017

Lightning over Lake Maracaibo

Lightning over Lake Maracaibo

Lake Maracaibo, Venezuela
October 2, 2013

Image Credit & Copyright: Ruzhugo27 via wikipedia.org

Star-Forming Regions

Star-Forming Regions

This image from NASA's Wide-field Infrared Survey Explorer, or WISE, highlights several star-forming regions. There are five distinct centers of star birth in this one image alone. Star-forming nebulae (called HII regions by astronomers) are clouds of gas and dust that have been heated up by nearby stars recently formed from the same cloud.

The largest, brightest cloud, in the upper right is known as Gum 22. It's named after Colin Gum, an Australian astronomer who surveyed the southern hemisphere sky in the early 1950's looking for star-forming regions like these. He catalogued 85 new such regions, named Gum 1 to85 (Gum Crater on the moon was also named in his honor).

Going counter-clockwise from Gum 22, the other catalogued nebulae in the image are Gum 23 (part of same cloud as 22), IRAS 09002-4732 (orange cloud near center), Bran 226 (upper cloud of the two at lower left), and finally Gum 25 at far lower left. There are also several smaller and/or more distant regions scattered throughout the image that have yet to be catalogued. Most of the regions are thought to be part of our local Orion spiral arm spur in the Milky Way galaxy. Their distances range from about 4,000 to 10,000 light-years away.

Notice the very bright green star near the lower right portion of the image. You can tell it's a star because it appears to have 'spikes' sticking out of it (diffraction spikes like these are an optical effect caused by the structure of the telescope). Bright stars in WISE images are typically blue, so you know this one is special. Known as IRAS 08535-4724, it's a unique type of stellar giant called a carbon star. Carbon stars are similar to red giants stars, which are much larger than the sun, glow brightly in longer wavelengths, and are in the late stages of their lives. But they have unusually high amounts of carbon in their outer atmospheres. Astronomers think this carbon comes either from convection currents deep within a star's core, or from a nearby neighboring star, from which it is siphoned. Recent evidence suggests that a carbon star like this one will end its life in an extremely powerful explosion called a gamma-ray burst, briefly outshining the sun a million trillion times.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light of 12 and 22 microns, respectively, which is mostly emitted by dust.

Image Credit: NASA/JPL-Caltech/UCLA
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA14105

Orion Nebula

Orion Nebula

This image shows smaller, particularly interesting areas of the Orion Nebula. It shows the delicate tracery created at the so-called Bright Bar, as the intense UV-light and strong winds from the hot Trapezium stars eat their way into the surrounding molecular cloud. Also visible are a number of very young red objects partly hidden in the cloud, waiting to be revealed as new members of the Trapezium Cluster.

Image Credit: ESO/M.McCaughrean et al. (AIP)
Explanation from: https://www.eso.org/public/images/eso0104c/

Six views of the Moon

Six views of the MoonSix views of the MoonSix views of the MoonSix views of the MoonSix views of the MoonSix views of the Moon

Six orthographic views of the Moon created from the new WAC global mosaic. From upper left to lower right the central longitude is 0°, 60°, 120°, 180°, 240°, 300°

Image Credit: NASA/GSFC/ Arizona State University

Jupiter's Southern Lights

Jupiter's Southern Lights

The complexity and richness of Jupiter's "southern lights" (also known as auroras) are on display in this animation of false-color maps from NASA's Juno spacecraft. Auroras result when energetic electrons from the magnetosphere crash into the molecular hydrogen in the Jovian upper atmosphere. The data for this animation were obtained by Juno's Ultraviolet Spectrograph.

The images are centered on the south pole and extend to latitudes of 50 degrees south. Each frame of the animation includes data from 30 consecutive Juno spins (about 15 minutes), just after the spacecraft's fifth close approach to Jupiter on February 2, 2017. The eight frames of the animation cover the period from 13:40 to 15:40 UTC at Juno. During that time, the spacecraft was receding from 35,000 miles to 153,900 miles (56,300 kilometers to 247,600 kilometers) above the aurora; this large change in distance accounts for the increasing fuzziness of the features.

Jupiter's prime meridian is toward the bottom, and longitudes increase counterclockwise from there. The sun was located near the bottom at the start of the animation, but was off to the right by the end of the two-hour period.

The red coloring of some of the features indicates that those emissions came from deeper in Jupiter's atmosphere; green and white indicate emissions from higher up in the atmosphere.

Image Credit: NASA/JPL-Caltech/SwRI
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21643

Spiral Galaxy IC 342

Spiral Galaxy IC 342

Looking like a spiders web swirled into a spiral, the galaxy IC 342 presents its delicate pattern of dust in this image from NASAs Spitzer Space Telescope. Seen in infrared light, the faint starlight gives way to the glowing bright patterns of dust found throughout the galaxys disk.

At a distance of about 10 million light-years, IC 342 is relatively close by galaxy standards, however our vantage point places it directly behind the disk of our own Milky Way. The intervening dust makes it difficult to see in visible light, but infrared light penetrates this veil easily. It belongs to the same group as its even more obscured galaxy neighbor, Maffei 2.

IC 342 is nearly face-on to our view giving a clear, top-down view of the structure of its disk. It has a low surface brightness compared to other spirals, indicating a lower density of stars (seen here in blue). Its dust structures show up much more vividly (yellow-green).

New stars are forming in the disk at a healthy clip. Glowing like gems trapped in the web, regions of heavy star formation appear as yellow-red dots due to the glow of warm dust. The very center glows especially brightly in the infrared, highlighting an enormous burst of star formation occurring in this tiny region. To either side of the center, a small bar of dust and gas is helping to fuel this central star formation.

Data from Spitzers infrared array camera (IRAC) are shown in blue (3.6 and 4.5 microns) and green (5.8 and 8.0 microns) while the multiband imaging photometer (MIPS) observation is red (24 microns).

Image Credit: NASA/JPL-Caltech/J. Turner (UCLA)
Explanation from: http://www.spitzer.caltech.edu/images/3669-sig11-009-A-Twisted-Star-Forming-Web-in-the-Galaxy-IC-342

May 23, 2017

Catatumbo Lightning

Catatumbo Lightning

Catatumbo lightning is an atmospheric phenomenon in Venezuela. It occurs only over the mouth of the Catatumbo River where it empties into Lake Maracaibo.

It originates from a mass of storm clouds at a height of more than 1 km, and occurs during 260 nights a year, 10 hours per day and up to 280 times per hour. It occurs over and around Lake Maracaibo, typically over the bog area formed where the Catatumbo River flows into the lake.

Catatumbo lightning changes its frequency throughout the year, and it is different from year to year. For example, it ceased from January to March 2010, apparently due to drought, temporarily raising fears that it might have been extinguished permanently.

Lake Maracaibo, Venezuela
November 1, 2015

Image Credit & Copyright: Fernando Flores
Explanation from: https://en.wikipedia.org/wiki/Catatumbo_lightning

Spiral Galaxy NGC 7714

Spiral Galaxy NGC 7714

NGC 7714 is a spiral galaxy 100 million light-years from Earth — a relatively close neighbour in cosmic terms.

The galaxy has witnessed some violent and dramatic events in its recent past. Tell-tale signs of this brutality can be seen in NGC 7714's strangely shaped arms, and in the smoky golden haze that stretches out from the galactic centre — caused by an ongoing merger with its smaller galactic companion NGC 7715, which is out of the frame of this image.

Image Credit: ESA, NASA
Explanation from: https://www.spacetelescope.org/images/heic1503a/

Open Star Cluster NGC 3572

Open Star Cluster NGC 3572

The Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile has captured the best image so far of the star cluster NGC 3572, a gathering of young stars, and its spectacular surroundings. This new image shows how the clouds of gas and dust around the cluster have been sculpted into whimsical bubbles, arcs and the odd features known as elephant trunks by the stellar winds flowing from the bright stars. The brightest of these cluster stars are heavier than the Sun and will end their short lives as supernova explosions.

Image Credit: ESO/G. Beccari
Explanation from: https://www.eso.org/public/images/eso1347a/

Colima Volcano Eruption

Colima Volcano Eruption

Colima, Mexico
2015

Image Credit: Hernando Rivera Cervantes/SWNS

Emission Nebula Sh2-308

Emission Nebula Sh2-308

The NASA/ESA Hubble Space Telescope still has a few tricks up its sleeve in its task of exploring the Universe. For one, it is able to image two adjacent parts of the sky simultaneously. It does this using two different cameras — one camera can be trained on the target object itself, and the other on a nearby patch of sky so that new and potentially interesting regions of the cosmos can be observed at the same time (these latter observations are known as parallel fields).

This image shows part of a bubble-like cloud of gas — a nebula named Sh2-308 — surrounding a massive and violent star named EZ Canis Majoris. It uses observations from Hubble’s Advanced Camera for Surveys, and is the parallel field associated with another view of the nebula produced by Hubble’s Wide Field Camera 3.

EZ Canis Majoris is something known as a Wolf-Rayet star, and is one of the brightest known stars of its kind. Its outer shell of hydrogen gas has been used up, revealing inner layers of heavier elements that burn at ferocious temperatures. The intense radiation pouring out from EZ Canis Majoris forms thick stellar winds that whip up nearby material, sculpting and blowing it outwards.

These processes have moulded the surrounding gas into a vast bubble. A bubble nebula produced by a Wolf-Rayet star is made of ionised hydrogen (HII), which is often found in interstellar space. In this case, it is the outer hydrogen layers of EZ Canis Majoris — the bubble — that are being inflated by the deluge of radiation — the air — coming from the central star. The fringes of these bubbles are nebulous and wispy, as can be seen in this image.

Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1721a/

Saturn

Saturn

The projection of Saturn's shadow on the rings grows shorter as Saturn's season advances toward northern summer, thanks to the planet's permanent tilt as it orbits the Sun. This will continue until Saturn's solstice in May 2017. At that point in time, the shadow will extend only as far as the innermost A ring, leaving the middle and outer A ring completely free of the planet's shadow.

Over the course of NASA's Cassini mission, the shadow of Saturn first lengthened steadily until equinox in August 2009. Since then, the shadow has been shrinking. These changes can be seen by comparing the shadow in the above view to its appearance as Cassini approached Saturn in 2004, equinox in 2009, and two years ago, in 2015.

This view looks toward the sunlit side of the rings from about 10 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Feb. 3, 2017.

The view was acquired at a distance of approximately 760,000 miles (1.2 million kilometers) from Saturn. Image scale is 46 miles (73 kilometers) per pixel.

Image Credit: NASA/JPL-Caltech/Space Science Institute
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21328

May 21, 2017

Storm seen from plane above Venezuela

Storm seen from plane above Venezuela

Plane above Caracas, Venezuela
Sepember 12, 2015

Image Credit & Copyright: Santiago Borja

Supernova Remnant RCW 86

Supernova Remnant RCW 86

This image combines data from four different space telescopes to create a multi-wavelength view of all that remains of the oldest documented example of a supernova, called RCW 86. The Chinese witnessed the event in 185 A.D., documenting a mysterious "guest star" that remained in the sky for eight months. X-ray images from the European Space Agency's XMM-Newton Observatory and NASA's Chandra X-ray Observatory are combined to form the blue and green colors in the image. The X-rays show the interstellar gas that has been heated to millions of degrees by the passage of the shock wave from the supernova.

Infrared data from NASA's Spitzer Space Telescope, as well as NASA's Wide-Field Infrared Survey Explorer (WISE) are shown in yellow and red, and reveal dust radiating at a temperature of several hundred degrees below zero, warm by comparison to normal dust in our Milky Way galaxy.

By studying the X-ray and infrared data together, astronomers were able to determine that the cause of the explosion witnessed nearly 2,000 years ago was a Type Ia supernova, in which an otherwise-stable white dwarf, or dead star, was pushed beyond the brink of stability when a companion star dumped material onto it. Furthermore, scientists used the data to solve another mystery surrounding the remnant -- how it got to be so large in such a short amount of time. By blowing a wind prior to exploding, the white dwarf was able to clear out a huge "cavity," a region of very low-density surrounding the system. The explosion into this cavity was able to expand much faster than it otherwise would have.

This is the first time that this type of cavity has been seen around a white dwarf system prior to explosion. Scientists say the results may have significant implications for theories of white-dwarf binary systems and Type Ia supernovae.

RCW 86 is approximately 8,000 light-years away. At about 85 light-years in diameter, it occupies a region of the sky in the southern constellation of Circinus that is slightly larger than the full moon.

Image Credit: NASA/JPL-Caltech/B. Williams (NCSU)
Explanation from: http://www.spitzer.caltech.edu/images/4777-sig11-019-All-Eyes-on-Oldest-Recorded-Supernova

Spiral Galaxy NGC 2841

Spiral Galaxy NGC 2841

Star formation is one of the most important processes in shaping the Universe; it plays a pivotal role in the evolution of galaxies and it is also in the earliest stages of star formation that planetary systems first appear.

Yet there is still much that astronomers don’t understand, such as how do the properties of stellar nurseries vary according to the composition and density of gas present, and what triggers star formation in the first place? The driving force behind star formation is particularly unclear for a type of galaxy called a flocculent spiral, such as NGC 2841 shown here, which features short spiral arms rather than prominent and well-defined galactic limbs.

Image Credit: NASA, ESA and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
Explanation from: https://www.spacetelescope.org/images/heic1104a/

Lightning seen from plane above Colombia

Lightning seen from plane above Colombia

Plane above Colombia
February 17, 2017

Image Credit & Copyright: Santiago Borja

Star-Forming Region S106

Star-Forming Region S106

This image shows Sh 2-106, or S106 for short. This is a compact star forming region in the constellation Cygnus (The Swan). A newly-formed star called S106 IR is shrouded in dust at the centre of the image, and is responsible for the surrounding gas cloud’s hourglass-like shape and the turbulence visible within. Light from glowing hydrogen is coloured blue in this image.

The image combines observations from the Hubble Space Telescope (in the centre) with images from the National Astronomical Observatory of Japan’s Subaru Telescope to extend the field of view around the edges of the image.

Image Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA) and NAOJ
Explanation from: https://www.spacetelescope.org/images/heic1118b/

Globular Cluster NGC 6388

Globular Cluster NGC 6388

This image from the NASA/ESA Hubble Space Telescope shows NGC 6388, a dynamically middle-aged globular cluster in the Milky Way. While the cluster formed in the distant past (like all globular clusters, it is over ten billion years old), a study of the distribution of bright blue stars within the cluster shows that it has aged at a moderate speed, and its heaviest stars are in the process of migrating to the centre.

A new study using Hubble data has discovered that globular clusters of the same age can have dramatically different distributions of blue straggler stars within them, suggesting that clusters can age at substantially different rates.

Image Credit: NASA, ESA, F. Ferraro (University of Bologna)
Explanation from: https://www.spacetelescope.org/images/heic1221a/