Astronomy with a large helping of physics and a pinch of the other sciences.
The Red Rectangle Nebula from Hubble
Image Credit: ESA, Hubble, NASA; Reprocessing: Steven Marx, Hubble Legacy ArchiveExplanation: How was the unusual Red Rectangle nebula created? At the nebula’s center is an aging binary star system that surely powers the nebula but does not, as yet, explain its colors. The unusual shape of the Red Rectangle is likely due to a thick dust torus which pinches the otherwise spherical outflow into tip-touching cone shapes. Because we view the torus edge-on, the boundary edges of the cone shapes seem to form an X. The distinct rungs suggest the outflow occurs in fits and starts. The unusual colors of the nebula are less well understood, however, and speculation holds that they are partly provided by hydrocarbon molecules that may actually be building blocks for organic life. The Red Rectangle nebula lies about 2,300 light years away towards the constellation of the Unicorn (Monoceros). The nebula is shown above in great detail as recently reprocessed image from Hubble Space Telescope. In a few million years, as one of the central stars becomes further depleted of nuclear fuel, the Red Rectangle nebula will likely bloom into a planetary nebula.
APOD | 2013 May 20 | Blue Sun Bursting
Image Credit & Copyright: Alan Friedman (Averted Imagination)Explanation: Our Sun is not a giant blueberry. Our Sun can be made to appear similar to the diminutive fruit, however, by imaging it in a specific color of extreme violet light called CaK that is emitted by the very slight abundance of ionized Calcium in the Sun’s atmosphere, and then false color-inverting the image. This solar depiction is actually scientifically illuminating as a level of the Sun’s chromosphere appears quite prominent, showing a crackly textured surface, cool sunspots appearing distinctly bright, and surrounding hot active regions appearing distinctly dark. The Sun is currently near the maximum activity level in its 11 year cycle, and has emitted powerful flares over the past week. During times of high activity, streams of energetic particles from Sun may impact the Earth’s magnetosphere and set off spectacular auroras.
APOD | 2013 May 19 | Earth’s Richat Structure
Image Credit: NASA/GSFC/METI/Japan Space Systems, and U.S./Japan ASTER Science TeamExplanation: What on Earth is that? The Richat Structure in the Sahara Desert of Mauritania is easily visible from space because it is nearly 50 kilometers across. Once thought to be an impact crater, the Richat Structure’s flat middle and lack of shock-altered rock indicates otherwise. The possibility that the Richat Structure was formed by a volcanic eruption also seems improbable because of the lack of a dome of igneous or volcanic rock. Rather, the layered sedimentary rock of the Richat structure is now thought by many to have been caused by uplifted rock sculpted by erosion. The above image was captured by the ASTER instruments onboard the orbiting orbiting Terra satellite. Why the Richat Structure is nearly circular remains a mystery.
APOD | 2013 May 18 | Comet PanSTARRS Anti-Tail
Image Credit & Copyright: Marco Fulle (INAF)Explanation: Once the famous sunset comet, PanSTARRS (C/2011 L4) is now visible all night from much of the northern hemisphere, bound for the outer solar system as it climbs high above the ecliptic plane. Dimmer and fading, the comet’s broad dust tail is still growing, though. This widefield telescopic image was taken against the starry background of the constellation Cepheus on May 15. It shows the comet has developed an extensive anti-tail, dust trailing along the comet’s orbit (to the left of the coma), stretching more than 3 degrees across the frame. Since the comet is just over 1.6 astronomical units from planet Earth, that corresponds to a distance of over 12 million kilometers. In late May Comet PanSTARRS will pass within a few degrees of the north celestial pole.
The Waterfall and the World at Night
Image Credit & Copyright: Stéphane Vetter (Nuits sacrées)Explanation: Above this boreal landscape, the arc of the Milky Way and shimmering aurorae flow through the night. Like an echo, below them lies Iceland’s spectacular Godafoss, the Waterfall of the Gods. Shining just below the Milky Way, bright Jupiter is included in the panoramic nightscape recorded on March 9. Faint and diffuse, the Andromeda Galaxy (M31) appears immersed in the auroral glow. The digital stitch of four frames is a first place winner in the 2013 International Earth and Sky Photo Contest on Dark Skies Importance organized by The World at Night. An evocative record of the beauty of planet Earth’s night sky, all the contest’s winning entries are featured in this video.
Kepler’s Supernova Remnant in X-Rays
Image Credit: X-ray: NASA/CXC/NCSU/M. Burkey et al. Optical: DSSExplanation: What caused this mess? Some type of star exploded to create the unusually shaped nebula known as Kepler’s supernova remnant, but which type? Light from the stellar explosion that created this energized cosmic cloud was first seen on planet Earth in October 1604, a mere four hundred years ago. The supernova produced a bright new star in early 17th century skies within the constellation Ophiuchus. It was studied by astronomer Johannes Kepler and his contemporaries, without the benefit of a telescope, as they searched for an explanation of the heavenly apparition. Armed with a modern understanding ofstellar evolution, early 21st century astronomers continue to explore the expanding debris cloud, but can now use orbiting space telescopes to survey Kepler’s supernova remnant (SNR) across the spectrum. Recent X-ray data and images of Kepler’s supernova remnant taken by the orbiting Chandra X-ray Observatory has shown relative elemental abundances typical of a Type Ia supernova, and further indicated that the progenitor was a white dwarf star that exploded when it accreted too much material from a companion Red Giant star and went over Chandrasekhar’s limit. About 13,000 light years away, Kepler’s supernovarepresents the most recent stellar explosion seen to occur within our Milky Way galaxy.
Galaxy Collisions: Simulation vs Observations
The folks over at NASA apod just put up an awesome galaxy collisions, simulations and observations video for the public. I made a little gif set to go along with the video which can be found here.
What happens when two galaxies collide? Although it may take over a billion years, such titanic clashes are quite common.
Images Credit: NASA, ESA; Visualization: Frank Summers (STScI);
Simulation: Chris Mihos (CWRU) & Lars Hernquist (Harvard).
Since galaxies are mostly empty space, no internal stars are likely to themselves collide. Rather the gravitation of each galaxy will distort or destroy the other galaxy, and the galaxies may eventually merge to form a single larger galaxy.
Expansive das and dust clouds collide and trigger waves of star formation that complete even during the interaction process. Pictured above is a computer simulation of two large spiral galaxies colliding, interspersed with real still images taken by the Hubble Space Telescope.
Our own Milky Way Galaxy has absorbed several smaller galaxies during its existence and is even projected to merge with the larger neighboring Andromeda galaxy in a few billion years.
Partial Solar Eclipse with Airplane
Image Credit & Copyright: Phillip CalaisExplanation: It was just eight minutes after sunrise, last week, and already there were four things in front of the Sun. The largest and most notable was Earth’s Moon, obscuring a big chunk of the Sun’s lower limb as it moved across the solar disk, as viewed from Fremantle, Australia. This was expected as the image was taken during a partial solar eclipse — an eclipse that left sunlight streaming around all sides of the Moon from some locations. Next, a band of clouds divided the Sun horizontally while showing interesting internal structure vertically. The third intervening body might be considered to be the Earth’s atmosphere, as it dimmed the Sun from its higher altitude brightness while density fluctuations caused the Sun’s edges to appear to shimmer. Although closest to the photographer, the least expected solar occulter was an airplane. Quite possibly, passengers on both sides of that airplane were contemplating the unusual view only visible out the eastern-facing windows.
Clouds, Birds, Moon, Venus
Image Credit & Copyright: Isaac Gutiérrez Pascual (Spain)Explanation: Sometimes the sky above can become quite a show. In early September of 2010, for example, the Moon and Venus converged, creating quite a sight by itself for sky enthusiasts around the globe. From some locations, though, the sky was even more picturesque. In the above image taken in Spain, a crescent Moon and the planet Venus, on the far right, were captured during sunset posing against a deep blue sky. In the foreground, dark storm clouds loom across the image bottom, while a white anvil cloud shape appears above. Black specks dot the frame, caused by a flock of birds taking flight. Very soon after this picture was taken, however, the birds passed by, the storm ended, and Venus and the Moon set. Bright Venus again becomes visible just after sunset this 2013 May and will appear near Jupiter toward the end of the month.
Cape York Annular Eclipse
Image Credit & Copyright: Courtesy Cameron McCarty -
MWV Observatory, Coca-Cola Space Science Center, Columbus State Univ. Eclipse TeamExplanation: This week the shadow of the New Moon fell on planet Earth, crossing Queensland’s Cape York in northern Australia … for the second time in six months. On the morning of May 10, the Moon’s apparent size was too small to completely cover the Sun though, revealing a “ring of fire” along the central path of the annular solar eclipse. Near mid-eclipse from Coen, Australia, a webcast team captured this telescopic snapshot of the annular phase. Taken with a hydrogen-alpha filter, the dramatic image finds the Moon’s silhouette just within the solar disk, and the limb of the active Sun spiked with solar prominences. Still, after hosting back-to-back solar eclipses, northern Australia will miss the next and final solar eclipse of 2013. This November, a rare hybrid eclipse will track across the North Atlantic and equatorial Africa.
Messier 77
Image Credit: NASA, ESA, André van der HoevenExplanation: Face-on spiral galaxy M77 lies a mere 47 million light-years away toward the aquatic constellation Cetus. At that estimated distance, the gorgeous island universe is about 100 thousand light-years across. Also known as NGC 1068, its compact and very bright core is well studied by astronomers exploring the mysteries of supermassive black holes in active Seyfert galaxies. M77 is also seen at x-ray, ultraviolet, infrared, and radio wavelengths. But this sharp visible light image based on Hubble data follows its winding spiral arms traced by obscuring dust clouds and red-tinted star forming regions close in to the galaxy’s luminous core.
Ring of Fire over Monument Valley
Image Credit & Copyright: Tunç Tezel (TWAN)Explanation: As the New Moon continues this season’s celestial shadow play, an annular solar eclipse track begins in western Australia at 22:30 UT on May 9 — near sunrise on May 10 local time. Because the eclipse occurs within a few days of lunar apogee, the Moon’s silhouette does not quite cover the Sun during mid-eclipse, momentarily creating a spectacular ring of fire. While a larger region witnesses a partial eclipse, the annular mid-eclipse phase is visible along a shadow track only about 200 kilometers wide but 13,000 kilometers long, extending across the central Pacific. For given locations along it, the ring of fire lasts from 4 to 6 minutes. Near the horizon, the appearance of the May 9/10 annular eclipse (online viewing) is suggested by this dramatic composite from May of 2012. The timelapse sequence depicts an annular eclipse in progress before sunset over Monument Valley in the southwestern United States.
Earth’s Major Telescopes Investigate GRB 130427A
Illustration Credit: NASA, DOE, Fermi LAT Collaboration
Explanation: A tremendous explosion has occurred in the nearby universe and major telescopes across Earth and space are investigating. Dubbed GRB 130427A, the gamma-ray burst was first detected by the Earth-orbiting Fermi and Swift satellites observing at high energies and quickly reported down to Earth. Within three minutes, the half-meter ISON telescope in New Mexico found the blast in visible light, noted its extreme brightness, and relayed more exact coordinates. Within the next few minutes, the bright optical counterpart was being tracked by several quickly re-pointable telescopes including the 2.0-meter P60 telescope in California, the 1.3-meter PAIRITEL telescope in Arizona, and the 2.0-meter Faulkes Telescope North in Hawaii. Within two hours, the 8.2-meter Gemini North telescope in Hawaii noted a redshift of 0.34, placing the explosion about 5 billion light years away — considered nearby in cosmological terms. Previously recorded images from the RAPTOR full-sky monitors were scanned and a very bright optical counterpart — magnitude 7.4 — was found 50 seconds before the Swift trigger. The brightest burst in recent years, a signal from GRB 130427A has also been found in low energy radio waves by the Very Large Array (VLA) and at the highest energies ever recorded by the Fermi satellite. Neutrino, gravitational wave, and telescopes designed to detect only extremely high energy photons are checking their data for a GRB 130427A signal. Pictured in the above animation, the entire gamma-ray sky is shown becoming momentarily dominated by the intense glow of GRB 130427A. Continued tracking the optical counterpart will surely be ongoing as there is a possibility that the glow of a classic supernova will soon emerge.
Image Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)“To see a vista like this takes patience, hiking, and a camera. Patience was needed in searching out just the right place and waiting for just the right time. A short hike was needed to reach this rugged perch above a secluded cove in Julia Pfeiffer Burns State Park in California, USA. And a camera was needed for the long exposure required to bring out the faint light from stars and nebula in the background Milky Way galaxy. Moonlight and a brief artificial flash illuminated the hidden beach and inlet behind nearby trees in the above composite image taken about two weeks ago. Usually obscured McWay Falls is visible just below the image center, while the Pacific Ocean is in view to its right.”
Tails of Comet Lemmon
Image Credit & Copyright: Gerald RhemannExplanation: What caused the interestingly intricate tails that Comet Lemmon displayed earlier this year? First of all, just about every comet that nears the Sun displays two tails: a dust tail and an ion tail. Comet Lemmon’s dust tail, visible above and around the comet nucleus in off-white, is produced by sun-light reflecting dust shed by the comet’s heated nucleus. Flowing and more sculptured, however, is C/2012 F6 (Lemmon)’s blue ion tail, created by the solar wind pushing ions expelled by the nucleus away from the Sun. Also of note is the coma seen surrounding Comet Lemmon’s nucleus, tinted green by atomic carbon gas fluorescing in sunlight. The above image was taken from the dark skies of Namibia in mid-April. Comet Lemmon is fading as it now heads back to the outer Solar System.
