Tag Archives: NASA

The Spinning Pulsar of the Crab Nebula

At the core of the Crab Nebula lies a city-sized, magnetized neutron star spinning 30 times a second. Known as the Crab Pulsar, it is the bright spot in the center of the gaseous swirl at the nebula’s core. About twelve light-years across, the spectacular picture frames the glowing gas, cavities and swirling filaments near the Crab Nebula’s center. The featured picture combines visible light from the Hubble Space Telescope in purple, X-ray light from the Chandra X-ray Observatory in blue, and infrared light from the Spitzer Space Telescope in red. Like a cosmic dynamo the Crab pulsar powers the emission from the nebula, driving a shock wave through surrounding material and accelerating the spiraling electrons. With more mass than the Sun and the density of an atomic nucleus,the spinning pulsar is the collapsed core of a massive star that exploded. The outer parts of the Crab Nebula are the expanding remnants of the star’s component gasses. The supernova explosion was witnessed on planet Earth in the year 1054. via NASA

Stardust and Comet Tails

Heading for its closest approach to the Sun, or perihelion, on December 19 comet C/2017 K2 (PanSTARRS) remains a sight for telescopic observers as it sweeps through planet Earth’s skies in the constellation Scorpius. The comet currently sports a greenish coma, long whitish dust tail, and short ion tail in this deep image from August 18. The 2×3 degree wide field of view includes part of the dusty nebula IC 4592 reflecting blue starlight. Also known as the Blue Horsehead Nebula, IC 4592 is about 400 light-years distant while the comet is just under 17 light-minutes away. First spotted at a distance well beyond the orbit of Saturn C/2017 K2 is on its maiden voyage to the inner solar system, a pristine visitor from the remote Oort cloud. via NASA

Saturn: 1993 2022

Saturn is the most distant planet of the Solar System easily visible to the unaided eye. With this extraordinary, long-term astro-imaging project begun in 1993, you can follow the ringed gas giant for one Saturn year as it wanders once around the ecliptic plane, finishing a single orbit around the Sun by 2022. Constructed from individual images made over 29 Earth years, the split panorama is centered along the ecliptic and crossed by the plane of our Milky Way galaxy. Saturn’s position in 1993 is at the right side, upper panel in the constellation Capricornus and progresses toward the left. It returns to the spot in Capricornus at left in the lower panel in 2022. The consistent imaging shows Saturn appears slightly brighter during the years 2000-2005 and 2015-2019, periods when its beautiful rings were tilted more face-on to planet Earth. via NASA

Full Moon Perseids

The annual Perseid meteor shower was near its peak on August 13. As planet Earth crossed through streams of debris left by periodic Comet Swift-Tuttle meteors rained in northern summer night skies. But even that night’s nearly Full Moon shining near the top of this composited view couldn’t hide all of the popular shower’s meteor streaks. The image captures some of the brightest perseid meteors in many short exposures recorded over more than two hours before the dawn. It places the shower’s radiant in the heroic constellation of Perseus just behind a well-lit medieval tower in the village of Sant Llorenc de la Muga, Girona, Spain. Observed in medieval times, the Perseid meteor shower is also known in Catholic tradition as the Tears of St. Lawrence, and festivities are celebrated close to the annual peak of the meteor shower. Joining the Full Moon opposite the Sun, bright planet Saturn also shines in the frame at the upper right. via NASA

Stargate Milky Way

There is a huge gate of stars in the sky, and you pass through it twice a day. The stargate is actually our Milky Way Galaxy, and it is the spin of the Earth that appears to propel you through it. More typically, the central band of our Milky Way appears as a faint band stretching across the sky, only visible in away from bright city lights. In a long-exposure wide-angle image from a dark location like this, though, the Milky Way’s central plane is easily visible. The featured picture is a digital composite involving multiple exposures taken on the same night and with the same camera, but employing a stereographic projection that causes the Milky Way to appear as a giant circular portal. Inside the stargate-like arc of our Galaxy is a faint stripe called zodiacal light — sunlight reflected by dust in our Solar System. In the foreground are cacti and dry rocks found in the rough terrain of the high desert of Chile, not far from the El Sauce Observatory and the developing Vera Rubin Observatory, the latter expected to begin routine operations in 2024. via NASA

A Meteor Wind over Tunisia

Does the Earth ever pass through a wind of meteors? Yes, and they are frequently visible as meteor showers. Almost all meteors are sand-sized debris that escaped from a Sun-orbiting comet or asteroid, debris that continues in an elongated orbit around the Sun. Circling the same Sun, our Earth can move through an orbiting debris stream, where it can appear, over time, as a meteor wind. The meteors that light up in Earth’s atmosphere, however, are usually destroyed. Their streaks, though, can all be traced back to a single point on the sky called the radiant. The featured image composite was taken over two days in late July near the ancient Berber village Zriba El Alia in Tunisia, during the peak of the Southern Delta Aquariids meteor shower. The radiant is to the right of the image. A few days ago our Earth experienced the peak of a more famous meteor wind — the Perseids. via NASA

The Cygnus Wall of Star Formation

The North America nebula on the sky can do what the North America continent on Earth cannot — form stars. Specifically, in analogy to the Earth-confined continent, the bright part that appears as Central America and Mexico is actually a hot bed of gas, dust, and newly formed stars known as the Cygnus Wall. The featured image shows the star forming wall lit and eroded by bright young stars, and partly hidden by the dark dust they have created. The part of the North America nebula (NGC 7000) shown spans about 15 light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus). via NASA

4000 Exoplanets

Over 4000 planets are now known to exist outside our Solar System. Known as exoplanets, this milestone was passed last month, as recorded by NASA’s Exoplanet Archive. The featured video highlights these exoplanets in sound and light, starting chronologically from the first confirmed detection in 1992 and continuing into 2019. The entire night sky is first shown compressed with the central band of our Milky Way Galaxy making a giant U. Exoplanets detected by slight jiggles in their parents-star’s colors (radial velocity) appear in pink, while those detected by slight dips in their parent star’s brightness (transit) are shown in purple. Further, those exoplanets imaged directly appear in orange, while those detected by gravitationally magnifying the light of a background star (microlensing) are shown in green. The faster a planet orbits its parent star, the higher the accompanying tone played. The retired Kepler satellite has discovered about half of these first 4000 exoplanets in just one region of the sky, while the TESS mission is on track to find even more, all over the sky, orbiting the brightest nearby stars. Finding exoplanets not only helps humanity to better understand the potential prevalence of life elsewhere in the universe, but also how our Earth and Solar System were formed. via NASA

Herschel Crater on Mimas

Mimas, small 400 kilometer-diameter moon of Saturn, is host to 130 kilometer-diameter Herschel crater, one of the larger impact craters in the entire Solar System. The robotic Cassini spacecraft orbiting Saturn in 2010 recorded this startling view of small moon and big crater while making a 10,000-kilometer record close pass by the diminutive icy world. Shown in contrast-enhanced false color, the image data reveal more clearly that Herschel’s landscape is colored slightly differently from heavily cratered terrain nearby. The color difference could yield surface composition clues to the violent history of Mimas. Of course, an impact on Mimas any larger than the one that created the 130-kilometer Herschel might have destroyed the small moon of Saturn. via NASA

Perseids and MAGIC

On August 11, 2021 a multi-mirror, 17 meter-diameter MAGIC telescope reflected this starry night sky from the Roque de los Muchachos European Northern Observatory on the Canary Island of La Palma. MAGIC stands for Major Atmospheric Gamma Imaging Cherenkov. The telescopes can see the brief flashes of optical light produced in particle air showers as high-energy gamma rays impact the Earth’s upper atmosphere. To the dark-adapted eye the mirror segments offer a tantalizing reflection of stars and nebulae along the plane of our Milky Way galaxy. But directly behind the segmented mirror telescope, low on the horizon, lies the constellation Perseus. And on that date the dramatic composite nightscape also captured meteors streaming from the radiant of the annual Perseid meteor shower. This year the Perseid shower activity will again peak around August 13 but perseid meteors will have to compete with the bright light of a Full Moon. via NASA