Jumat, 23 Maret 2018
In this composite image, derived from data collected by the Jovian Infrared Auroral Mapper (JIRAM) instrument aboard NASA's Juno mission to Jupiter, shows the central cyclone at the planet's north pole and the eight cyclones that encircle it. JIRAM collects data in infrared, and the colors in this composite represent radiant heat: the yellow (thinner) clouds are about 9 degrees Fahrenheit (-13° Celsius) in brightness temperature and the dark red (thickest) are around -181 degrees Fahrenheit (-118.33° Celsius).
Image Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA22335
Jupiter's north pole seen by Juno spacecraft
Kamis, 22 Maret 2018
An international team of scientists has used the NASA/ESA Hubble Space Telescope to study the atmosphere of the hot exoplanet WASP-39b. By combining this new data with older data they created the most complete study yet of an exoplanet atmosphere. The atmospheric composition of WASP-39b hints that the formation processes of exoplanets can be very different from those of our own Solar System giants.
Investigating exoplanet atmospheres can provide new insight into how and where planets form around a star.“We need to look outward to help us understand our own Solar System,” explains lead investigator Hannah Wakeford from the University of Exeter in the UK and the Space Telescope Science Institute in the USA.
Therefore the British-American team combined the capabilities of the NASA/ESA Hubble Space Telescope with those of other ground- and space-based telescopes for a detailed study of the exoplanet WASP-39b. They have produced the most complete spectrum of an exoplanet’s atmosphere possible with present-day technology.
WASP-39b is orbiting a Sun-like star, about 700 light-years from Earth. The exoplanet is classified as a “Hot-Saturn”, reflecting both its mass being similar to the planet Saturn in our own Solar System and its proximity to its parent star. This study found that the two planets, despite having a similar mass, are profoundly different in many ways. Not only is WASP-39b not known to have a ring system, it also has a puffy atmosphere that is free of high-altitude clouds. This characteristic allowed Hubble to peer deep into its atmosphere.
By dissecting starlight filtering through the planet’s atmosphere the team found clear evidence for atmospheric water vapour. In fact, WASP-39b has three times as much water as Saturn does. Although the researchers had predicted they would see water vapour, they were surprised by the amount that they found. This surprise allowed to infer the presence of large amount of heavier elements in the atmosphere. This in turn suggests that the planet was bombarded by a lot of icy material which gathered in its atmosphere. This kind of bombardment would only be possible if WASP-39b formed much further away from its host star than it is right now.
“WASP-39b shows exoplanets are full of surprises and can have very different compositions than those of our Solar System,” says co-author David Sing from the University of Exeter, UK.
The analysis of the atmospheric composition and the current position of the planet indicate that WASP-39b most likely underwent an interesting inward migration, making an epic journey across its planetary system. “Exoplanets are showing us that planet formation is more complicated and more confusing than we thought it was. And that’s fantastic!”, adds Wakeford.
Having made its incredible inward journey WASP-39b is now eight times closer to its parent star, WASP-39, than Mercury is to the Sun and it takes only four days to complete an orbit. The planet is also tidally locked, meaning it always shows the same side to its star. Wakeford and her team measured the temperature of WASP-39b to be a scorching 750 degrees Celsius. Although only one side of the planet faces its parent star, powerful winds transport heat from the bright side around the planet, keeping the dark side almost as hot.
“Hopefully this diversity we see in exoplanets will help us figure out all the different ways a planet can form and evolve,”explains David Sing.
Looking ahead, the team wants to use the NASA/ESA/CSA James Webb Space Telescope — scheduled to launch in 2019 — to capture an even more complete spectrum of the atmosphere of WASP-39b. James Webb will be able to collect data about the planet’s atmospheric carbon, which absorbs light of longer wavelengths than Hubble can see. Wakeford concludes: “By calculating the amount of carbon and oxygen in the atmosphere, we can learn even more about where and how this planet formed.”
Image Credit: NASA, ESA, and G. Bacon (STScI)
Explanation from: https://www.spacetelescope.org/news/heic1804/
Exoplanet WASP-39b
Rabu, 21 Maret 2018
Berastagi, Sumatra, Indonesia
February 19, 2018
Image Credit: Reuters
Mount Sinabung Volcano Eruption
Rabu, 28 Februari 2018
Discovered in 1900 by astronomer DeLisle Stewart and here imaged by the NASA/ESA Hubble Space Telescope, IC 4710 is an undeniably spectacular sight. The galaxy is a busy cloud of bright stars, with bright pockets — marking bursts of new star formation — scattered around its edges.
IC 4710 is a dwarf irregular galaxy. As the name suggests, such galaxies are irregular and chaotic in appearance, lacking central bulges and spiral arms — they are distinctly different from spirals or ellipticals. It is thought that irregular galaxies may once have been spirals or ellipticals, but became distorted over time through external gravitational forces during interactions or mergers with other galaxies. Dwarf irregulars in particular are important to our overall understanding of galactic evolution, as they are thought to be similar to the first galaxies that formed in the Universe.
IC 4710 lies roughly 25 million light-years away in the southern constellation of Pavo (The Peacock). This constellation is located in the southern skies and also contains the third-brightest globular cluster in the sky, NGC 6752, the spiral galaxy NGC 6744, and six known planetary systems (including HD 181433 which is host to a super-Earth).
The data used to create this image were gathered by Hubble’s Advanced Camera for Surveys (ACS).
Image Credit: ESA/Hubble, NASA, Judy Schmidt
Explanation from: https://www.spacetelescope.org/images/potw1809a/
Dwarf Galaxy IC 4710
Selasa, 27 Februari 2018
Crews aboard the International Space Station oriented the camera specifically to capture this panorama of Hawaii's Kilauea volcano (image left) with the long swirls of volcanic gases (top half of the image) wafting west from the volcano. Astronauts are trained to take oblique images of hard-to-see atmospheric haze by shooting obliquely to enhance visibility. The gas haze--termed vog, a combination of fog, smog and volcanic--is well known in Hawai'i, and is defined as "a form of air pollution that results when sulfur dioxide and other gases ... emitted by an erupting volcano react with oxygen and moisture in the presence of sunlight".
Here the vog haze is transported hundreds of km downwind of the volcano (for scale the Big Island is 137 km, 85 miles, long). In this unusual view the vog forms a series of subtle but distinct alternating swirls (arrows) known as von Karman vortices, a favorite topic for crew photography. Swirls form under specific conditions of high atmospheric pressure and relatively slow wind speeds. They usually develop in clouds downwind of islands, as shown in many astronaut images of cloud patterns. Images of vog haze are captured often by astronauts, but few show the swirl phenomenon.
Image Credit: NASA
Explanation from: https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ISS042&roll=E&frame=281151
Hawaii seen from the International Space Station
Senin, 26 Februari 2018
Nestled in the young Ophiuchus star-forming region, 410 light-years from the Sun, a fascinating protoplanetary disc named AS 209 is slowly being carved into shape. This wonderful image was captured using the high-resolution ALMA telescope, revealing a curious pattern of rings and gaps in the dust surrounding a young star.
Protoplanetary discs are dense, rotating planes of gas and dust that surround newly formed stars; providing the matter that one day becomes orbiting planets, moons and other minor bodies. At less than one million years old, this system is very young, but already two clear gaps are being sculpted from the disc.
The outer gap is deep, wide, and largely a dust-free zone, leading astronomers to believe that a giant planet almost the mass of Saturn is orbiting here — around 800 light-minutes from the central star, and more than three times the distance between Neptune and the Sun! As the planet carves out its path, dust piles up at the outer edge of its orbit, creating ever more defined rings in the disc. The thinner, inner dust gap could have been formed by a smaller planet, but astronomers have raised the intriguing possibility that the large and distant circling planet in fact created both paths.
This inferred Saturn-like planet so far from its central star raises fascinating questions about planet formation at the edges of protoplanetary discs on particularly short timescales.
Image Credit: ALMA (ESO/NAOJ/NRAO)/ D. Fedele et al.
Explanation from: https://www.eso.org/public/images/potw1809a/
Protoplanetary Disk AS 209
Kamis, 15 Februari 2018
Captured by the NASA/ESA Hubble Space Telescope, the galaxy NGC 3344 presents itself face-on, allowing astronomers a detailed look at its intricate and elegant structure. And Hubble’s ability to observe objects over a wide range of different wavelengths reveals features that would otherwise remain invisible.
Spiral galaxies are some of the most spectacular sights in the sky, but to an observer they do not all look the same. Some are seen edge-on, giving astronomers an excellent idea of the galaxy’s vertical structure; others are seen at an angle, providing a hint of the size and structure of the spiral arms; while others are seen face-on, showcasing their arms and bright core in all their beauty.
Approximately 20 million light-years away in the constellation of Leo Minor (the Lion Cub), NGC 3344 is seen from a breathtaking face-on perspective. Half the size of the Milky Way, it is classified as a weakly barred spiral galaxy. The central bar is just visible in this image, taken with Hubble’s Wide Field Camera 3: an elongated lane of stars, trailing through the nucleus of the galaxy. Astronomers estimate that two-thirds of all spiral galaxies are barred, including our own Milky Way.
Hubble’s capacity to observe celestial objects in different wavelengths allows us to see more than just the spiral arms sweeping out loosely around the centre in a gorgeous whorl. This image is a composite of images taken through different filters, ranging from the near ultraviolet, to the optical and the near-infrared. Together they show a more complete picture of the galaxy than the human eye alone could possibly see.
The swirling spiral arms are the birthplace of new stars, whose high temperatures make them shine blue, resulting in them being easily identifiable in this image. Clouds of dust and gas distributed through the spiral arms — glowing red in this image — are reservoirs of material for even more stars. The bright jewel-like stars on the left of the picture, however, are much closer to Earth — they belong to our own galaxy and just happened to photobomb this Hubble image.
While its face-on orientation reveals much about NGC 3344’s detailed structure, this galaxy is still enigmatic; astronomers have noticed that some of its outer stars are moving in a strange way. Often, the high concentration of stars in the centre of a galaxy can affect the movements of the outer stars, but this does not seem to be the case in NGC 3344. Astronomers suspect that these weirdly behaving outer stars may actually have been stolen from another galaxy, after a close encounter that took place long ago.
The location of NGC 3344 is also intriguing. Our galaxy is part of the Local Group, which is made up of approximately 40 other galaxies, with the Andromeda Galaxy being the largest member. But NGC 3344 is not part of a local galactic neighbourhood like we are. It is actually part of a small spur that leads off the larger Virgo Supercluster — a gargantuan collection of several thousand galaxies.
But it stands out from these thousands of galaxies because of its beauty, which highlights to us the elegance of the Universe.
Image Credit: ESA/Hubble, NASA
Explanation from: https://www.spacetelescope.org/news/heic1803/
Spiral Galaxy NGC 3344
Rabu, 14 Februari 2018
As part of an engineering test, NASA’s OSIRIS-REx spacecraft captured this image of the Earth and Moon using its NavCam1 imager on January 17 from a distance of 39.5 million miles (63.6 million km). When the camera acquired the image, the spacecraft was moving away from home at a speed of 19,000 miles per hour (8.5 kilometers per second).
Earth is the largest, brightest spot in the center of the image, with the smaller, dimmer Moon appearing to the right. Several constellations are also visible in the surrounding space. The bright cluster of stars in the upper left corner is the Pleiades in the Taurus constellation. Hamal, the brightest star in Aries, is located in the upper right corner of the image. The Earth-Moon system is centered in the middle of five stars comprising the head of Cetus the Whale.
NavCam1, a grayscale imager, is part of the TAGCAMS (Touch-And-Go Camera System) navigation camera suite. Malin Space Science Systems designed, built, and tested TAGCAMS; Lockheed Martin integrated TAGCAMS to the OSIRIS-REx spacecraft and operates TAGCAMS.
Image Credit: NASA/Goddard/University of Arizona/Lockheed Martin
Explanation from: https://www.nasa.gov/image-feature/goddard/2018/osiris-rex-captures-new-earth-moon-image
Earth and Moon seen by OSIRIS-REx spacecraft from 63 million kilometers away
Selasa, 13 Februari 2018
September 22, 2015
Image Credit: NASA
The Nile at Night seen from the International Space Station
Senin, 12 Februari 2018
This ghostly image features a distant and pulsating red giant star known as R Sculptoris. Situated 1200 light-years away in the constellation of Sculptor, R Sculptoris is something known as a carbon-rich asymptotic giant branch (AGB) star, meaning that it is nearing the end of its life. At this stage, low- and intermediate-mass stars cool off, create extended atmospheres, and lose a lot of their mass — they are on their way to becoming spectacular planetary nebulae.
While the basics of this mass-loss process are understood, astronomers are still investigating how it begins near the surface of the star. The amount of mass lost by a star actually has huge implications for its stellar evolution, altering its future, and leading to different types of planetary nebulae. As AGB stars end their lives as planetary nebulae, they produce a vast range of elements — including 50% of elements heavier than iron — which are then released into the Universe and used to make new stars, planets, moons, and eventually the building blocks of life.
One particularly intriguing feature of R Sculptoris is its dominant bright spot, which looks to be two or three times brighter than the other regions. The astronomers that captured this wonderful image, using ESO’s Very Large Telescope Interferometer (VLTI), have concluded that R Sculptoris is surrounded by giant “clumps” of stellar dust that are peeling away from the shedding star. This bright spot is, in fact, a region around the star with little to no dust, allowing us to look deeper into the stellar surface.
This image captures an extremely small section of the sky: approximately 20x20 milliarcseconds. For comparison, Jupiter has an angular size of approximately 40 arcseconds.
Image Credit: ESO
Explanation from: https://www.eso.org/public/images/potw1807a/
R Sculptoris
Minggu, 11 Februari 2018
Roughly 50 million light-years away lies a somewhat overlooked little galaxy named NGC 1559. Pictured here by Hubble’s Wide Field Camera 3, this barred spiral lies in the little-observed southern constellation of Reticulum (The Reticule).
NGC 1559 has massive spiral arms chock-full of star formation, and is receding from us at a speed of about 1300 km/s. The galaxy contains the mass of around ten billion Suns — while this may sound like a lot, that is almost 100 times less massive than the Milky Way. Although NGC 1559 appears to sit near one of our nearest neighbours in the sky — the Large Magellanic Cloud (LMC), this is just a trick of perspective. In reality, NGC 1559 is physically nowhere near the LMC in space — in fact, it truly is a loner, lacking the company of any nearby galaxies or membership of any galaxy cluster.
Despite its lack of cosmic companions, when this lonely galaxy has a telescope pointed in its direction, it puts on quite a show! NGC 1559 has hosted a variety of spectacular exploding stars called supernovae, four of which we have observed — in 1984, 1986, 2005, and 2009 (SN 1984J, 1986L, 2005df [a Type Ia], and 2009ib [a Type II-P, with an unusually long plateau]).
NGC 1559 may be alone in space, but we are watching and admiring from far away.
Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1806a/
Spiral Galaxy NGC 1559
Sabtu, 10 Februari 2018
Navajo, Arizona
Image Credit: Ralph Lauer, ZUMA Press/Corbis
Storm and Lightning over Petrified Forest National Park
Jumat, 09 Februari 2018
The Sun has had no sunspots for almost two weeks (as of February 1, 2018) and just has a single, tiny one that appeared on January 31, 2018. This spotless period is a prelude to the approaching period of solar minimum next year, when the Sun's activity will be at the low end of its 11-year cycle.
Image Credit: NASA/GSFC/Solar Dynamics Observatory
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA22242
Spotless Sun
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