Astronomers are using NASA's Hubble Space Telescope to study auroras stunning light shows in a planet's atmosphere on the poles of the largest planet in the solar system, Jupiter. The auroras were photographed during a series of Hubble Space Telescope Imaging Spectrograph far-ultraviolet-light observations taking place as NASA's Juno spacecraft approaches and enters into orbit around Jupiter. The aim of the program is to determine how Jupiter's auroras respond to changing conditions in the solar wind, a stream of charged particles emitted from the sun. Auroras are formed when charged particles in the space surrounding the planet are accelerated to high energies along the planet's magnetic field. When the particles hit the atmosphere near the magnetic poles, they cause it to glow like gases in a fluorescent light fixture. Jupiter's magnetosphere is 20,000 times stronger than Earth's. These observations will reveal how the solar system's largest and most powerful magnetosphere behaves.
How far are you from a naturally dark night sky? In increasing steps, this world map (medium | large) shows the effect of artificial night sky brightness on the visual appearance of the night sky. The brightness was modeled using high resolution satellite data and fit to thousands of night sky brightness measurements in recent work. Color-coded levels are compared to the natural sky brightness level for your location. For example, artificial sky brightness levels in yellow alter the natural appearance of the night sky. In red they hide the Milky Way in an artificial luminous fog. The results indicate that the historically common appearance of our galaxy at night is now lost for more than one-third of humanity. That includes 60% of Europeans and almost 80% of North Americans, along with inhabitants of other densely populated, light-polluted regions of planet Earth. Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Rosetta is set to complete its mission in a controlled descent to the surface of its comet on 30 September.
The German Astronomical Society (AG) has announced that the most prestigious prize in Germany in the field of astronomy and astrophysics, the Karl Schwarzschild Medal, will be awarded this year to Robert Williams of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. In Robert Williams the AG honors not only an outstanding scientist, but also a man with a dedication to scientific training and astronomical outreach. His name is inseparably linked to the most celebrated observation target of the Hubble Space Telescope (HST): the famous Hubble Deep Field (HDF). The German Astronomical Society will award the Karl Schwarzschild Medal, whose previous recipients include five Nobel laureates, to Robert Williams on September 13, 2016, during the opening ceremony of the annual conference of the AG in Bochum, Germany. The award is named after the German physicist and astronomer Karl Schwarzschild (1863-1916), one of the pioneers of modern astrophysics.
This beautiful telephoto composition spans light-years in a natural night skyscape from the island of Crete. Looking south, exposures both track the stars and record a fixed foreground in three merged panels that cover a 10x12 degree wide field of view. The May 15 waxing gibbous moonlight illuminates the church and mountainous terrain. A mere 18 thousand light-years away, huge globular star cluster Omega Centauri (NGC 5139) shining above gives a good visual impression of its appearance in binoculars on that starry night. Active galaxy Centaurus A (NGC 5128) is near the top of the frame, some 11 million light-years distant. Also found toward the expansive southern constellation Centaurus and about the size of our own Milky Way is edge on spiral galaxy NGC 4945. About 13 million light-years distant it's only a little farther along, and just above the horizon at the right. Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Recent research showed that graphene (reduced graphene oxide, rGO) and graphene oxide (GO) particles larger than 1 micron in size are not cytotoxic or genotoxic to mouse lung cells. The study, performed using Graphenea graphene and involving the company's scientists, tested GO and rGO toxicity epithelial FE1 cells in vitro. GO and rGO have potential uses in biomedical applications, for example in biosensors, as a substrate in mass spectroscopy and for cell growth, and as drug delivery carriers.
Toxicity of nanoparticles (NP) is an important topic, due to the growing prevalence of NPs in research and production. Because of the multitude of compositions, shapes, and sizes of NPs, toxicity is an issue that needs to be addressed to each type of NP separately.
Figure: Morphology of GO and rGO (Wiley).
The first step in toxicity research always takes place “in vitro”, where cells are exposed to the potentially harmful agent and later analyzed for damage. The latest research, involving eight institutions from Denmark, France, and Spain, concluded that few layered GO and rGO with lateral size above 1 micrometer were not cytotoxic or genotoxic to FE1 mouse epithelial cells at concentrations up to 200 micrograms/ml. Mouse lung cells are commonly used in the first steps of toxicity studies. Although our study shows that no DNA strand breaks occur in cells due to exposure to GO and rGO particles of this size, earlier studies reveal that smaller particles, i.e. GO nanoparticles with sizes smaller than 500 nm, do cause DNA strand breaks. Carbon black has also been shown to be toxic and possibly carcinogenic to humans.
The research was published in the journal Environmental and Molecular Mutagenesis.
As we celebrate the Fourth of July by watching dazzling fireworks shows, another kind of fireworks display is taking place in a small, nearby galaxy.
Near the horizon the Full Moon often seems to loom large, swollen in appearance by the famous Moon illusion. But timelapse images demonstrate that the Moon's apparent size doesn't really change as it climbs toward the zenith. Its color does, though. Recording a frame every 10 seconds, this image shows how dramatic that color change can be. The composite follows a solstice Full Moon climbing above a rugged horizon over northwestern Indiana. A shrinking line-of-sight through planet Earth's dense and dusty atmosphere shifted the moonlight from strawberry red through honey-colored and paler yellowish hues. That change seems appropriate for a northern June Full Moon also known as the Strawberry or Honey Moon. Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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These three bright nebulae are often featured in telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula left of center, and colorful M20 near the bottom of the frame The third, NGC 6559, is right of M8, separated from the larger nebula by dark dust lanes. All three are stellar nurseries about five thousand light-years or so distant. The expansive M8, over a hundred light-years across, is also known as the Lagoon Nebula. M20's popular moniker is the Trifid. In the composite image, narrowband data records ionized hydrogen, oxygen, and sulfur atoms radiating at visible wavelengths. The mapping of colors and range of brightness used to compose this cosmic still life were inspired by Van Gogh's famous Sunflowers. Just right of the Trifid one of Messier's open star clusters, M21, is also included on the telescopic canvas. Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Pancake-shaped clouds not only appear in the children's book "Cloudy With a Chance of Meatballs," but also 3 billion miles away on the gaseous planet Neptune. When they appeared in July 2015, witnessed by amateur astronomers and the largest telescopes, scientists suspected that these clouds were bright companions to an unseen, dark vortex. The dark vortex is a high-pressure system where the flow of ambient air is perturbed and diverted upward over the vortex. This forms huge, lens-shaped clouds, that resemble clouds that sometimes form over mountains on Earth.
A Full Moon sets as the Solstice Sun rises in this June 20 dawn skyscape. Captured from a nearby peak in central California, planet Earth, the scene looks across the summit of Mount Hamilton and Lick Observatory domes on a calendar date that marks an astronomical change of seasons and hemispherical extremes of daylight hours. Earth's shadow stretches toward the Santa Cruz Mountains on the western horizon. Just above the atmospheric grey shadowband is a more colorful anti-twilight arch, a band of reddened, backscattered sunlight also known as the Belt of Venus. The interplay of solstice dates and lunar months does make this solstice and Full Moon a rare match-up. The next June solstice and Full Moon will fall on the same calendar date on June 21, 2062. Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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