Q 227: Question of the Day - 30 March 2013 (Week 13)
What is Extra-Galactic?
What is Extra-Galactic?
Saturday, March 30, 2013
Answer To Question 226
A226: An epoch is a division of a geologic period; it is the smallest division of geologic time, lasting several million years.
Hubble Sees J 900 Masquerading as a Double Star
The object in this image is Jonckheere 900 or J 900, a planetary nebula — glowing shells of ionized gas pushed out by a dying star. Discovered in the early 1900s by astronomer Robert Jonckheere, the dusty nebula is small but fairly bright, with a relatively evenly spread central region surrounded by soft wispy edges.
Green Meteorite May Be from Mercury, a First
This green meteorite that landed in Morocco in 2012 could be from Mercury. CREDIT: Stefan Ralew/sr-meteorites.de
Scientists may have discovered the first meteorite from Mercury.The green rock found in Morocco last year may be the first known visitor from the solar system's innermost planet, according to meteorite scientist Anthony Irving, who unveiled the new findings this month at the 44th annual Lunar and Planetary Science Conference in The Woodlands, Texas. The study suggests that a space rock called NWA 7325 came from Mercury, and not an asteroid or Mars.
New Crew Aboard Station After Express Flight
The Soyuz TMA-08M spacecraft carrying three new Expedition 35 crew members docked with the International Space Station’s Poisk module at 10:28 p.m. EDT Thursday, completing its accelerated journey to the orbiting complex in less than six hours.
NASA's Swift Sizes Up Comet ISON
Astronomers from the University of Maryland at College Park (UMCP) and Lowell Observatory have used NASA's Swift satellite to check out comet C/2012 S1 (ISON), which may become one of the most dazzling in decades when it rounds the sun later this year.
Friday, March 29, 2013
Mars beckons ISRO, orbiter taking shape
This file photo made available by NASA shows Mars photographed by the Hubble Space Telescope on the planet's closest approach to Earth in 60,000 years
The mother of all Indian space designs to date, Mars Orbiter Mission or MOM for now, is shaping up at a feverish pace at the satellite assembly centre here. It has a hit or miss date to keep. The earliest once-in-26-months window of opportunity opens in October.
Answer To Question 225
A225: An Ephemeris is a table listing the spatial coordinates of celestial bodies and spacecraft as a function of time.
Bluish Color in Broken Rock in 'Yellowknife Bay'
The Mast Camera (Mastcam) on NASA's Mars rover Curiosity showed researchers interesting internal color in this rock called "Sutton_Inlier," which was broken by the rover driving over it. The Mastcam took this image during the 174th Martian day, or sol, of the rover's work on Mars (Jan. 31, 2013). The rock is about 5 inches (12 centimeters) wide at the end closest to the camera. This view is calibrated to estimated "natural" color, or approximately what the colors would look like if we were to view the scene ourselves on Mars. The inside of the rock, which is in the "Yellowknife Bay" area of Gale Crater, is much less red than typical Martian dust and rock surfaces, with a color verging on grayish to bluish.
Image credit: NASA/JPL-Caltech/MSSS/ASU
Variation in Subsurface Water In 'Yellowknife Bay'
View From Camera Not Used During Curiosity's First Six Months on Mars
This view of Curiosity's left-front and left-center wheels and of marks made by wheels on the ground in the "Yellowknife Bay" area comes from one of six cameras used on Mars for the first time more than six months after the rover landed. The left Navigation Camera (Navcam) linked to Curiosity's B-side computer took this image during the 223rd Martian day, or sol, of Curiosity's work on Mars (March 22, 2013). The wheels are 20 inches (50 centimeters) in diameter.
Churning Out Stars
W3 is an enormous stellar nursery about 6,200 light-years away in the Perseus Arm, one of the Milky Way galaxy’s main spiral arms, which hosts both low- and high-mass star formation. In this image from the Herschel space observatory, the low-mass forming stars are seen as tiny yellow dots embedded in cool red filaments, while the highest-mass stars -- with greater than eight times the mass of our sun -- emit intense radiation, heating up the gas and dust around them and appearing here in blue.
Thursday, March 28, 2013
Answer To Question 224
A224: Earthshine is the faint light that is reflected from the Earth onto the dark part of the moon.
Herbig-Haro 110
The NASA/ESA Hubble Space Telescope has captured a new image of Herbig-Haro 110, a geyser of hot gas flowing from a newborn star as seen in this beautiful space wallpaper. HH 110 appears different from most other Herbig-Haro objects: in particular, it appears on its own while they usually come in pairs. Astronomers think it may be a continuation of another object called HH 270, after it has been deflected off a dense cloud of gas. This image was released July 3, 2012.
Credit: NASA, ESA and the Hubble Heritage team (STScI/AURA)
Global View of Iapetus' Dichotomy
These two global images of Iapetus show the extreme brightness dichotomy on the surface of this peculiar Saturnian moon. The left-hand panel shows the moon's leading hemisphere and the right-hand panel shows the moon's trailing side. While low and mid latitudes of the leading side exhibit a surface almost as dark as charcoal, broad tracts of the trailing side are almost as bright as snow. The dark terrain covers about 40 percent of the surface and is named Cassini Regio. The names of the bright terrain are Roncevaux Terra (north) and Saragossa Terra (south).
Bright Moons
The Cassini spacecraft observes three of Saturn's moons set against the darkened night side of the planet.
Saturn is present on the left this image but is too dark to see. Rhea (1,528 kilometers, or 949 miles across) is closest to Cassini here and appears largest at the center of the image. Enceladus (504 kilometers, or 313 miles across) is to the right of Rhea. Dione (1,123 kilometers, or 698 miles across) is to the left of Rhea, partly obscured by Saturn.
Wednesday, March 27, 2013
Answer To Question 223
A223: The Doppler shift (or Doppler Effect) is an increase or decrease in wavelength as the object emitting the wave moves relative to the observer. For example, a train whistle seems to be higher in pitch when the train is approaching you (the waves are compressed, shortening the wavelength), and lower in pitch when it is traveling away from you (the waves are elongated, lengthening the wavelength). The same thing happens with light waves when the light source is coming or going relative to us. For example, when a star is travelling away from Earth, its light appears redder (the light waves are elongated, lengthening the wavelength); this is called the red shift. The expansion of the universe was discovered when E. Hubble observed that the light from almost all other galaxies was red-shifted. The Doppler effect was named for Johann Christian Doppler (November 29, 1803-March 17, 1853), who first realized that it existed (1842).
Magnetometer
MAVEN’s dual magnetometers will allow scientists to study the interaction between the solar wind and the Martian atmosphere, giving us a better understanding of how Mars has evolved from a warm, wet climate to the cold, arid one we see today.
Moon and Asteroids Share Cosmic History
Scientists have now discovered that studying meteorites from the giant asteroid Vesta helps scientists understand the event known as the "Lunar Cataclysm," when a repositioning of the gas giant planets destabilized a portion of the asteroid belt and triggered a solar-system-wide bombardment. Previously, researchers had only lunar samples to work with. Scientists are now using a class of meteorites known as howardite, eucrite and diogenite meteorites, that are connected to Vesta to study the lunar cataclysm, providing about three times more samples to analyze.
The left-hand mosaic of the far side of the moon is based on data from NASA's Lunar Reconnaissance Orbiter. On the right is an image of the giant asteroid Vesta from data obtained by NASA's Dawn spacecraft. The insets show thin sections of the lunar sample 10069-13 and eucrite NWA1978. Image credit: NASA/GSFC/ASU/JPL-Caltech/UCLA/MPS/DLR/IDA
Webb Telescope
A full-scale model of the James Webb Space Telescope was built by the prime contractor, Northrop Grumman, to provide a better understanding of the size, scale and complexity of the observatory. The model is constructed mainly of aluminum and steel, weighs 12,000 lb., and is approximately 80 feet long, 40 feet wide and 40 feet tall. The model requires 2 trucks to ship it and assembly takes a crew of 12 approximately four days.Credit: Bobby Bradley/NASA
Dragon Spacecraft Returns to Earth
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Investigations included among the returned cargo could aid in food production during future long-duration space missions and enhance crop production on Earth.
Monday, March 25, 2013
Meteorites Revealing Secrets of Russian Fireball
Scientists studying small pieces of the meteor that exploded over the Russian city of Chelyabinsk on Feb. 15 are working to glean new insights into the rare impact by a space rock.
Saturday, March 23, 2013
Answer To Question 220
A220: NASA's Deep Space Network (DSN) is an international network of antennas that communicate with spacecraft and perform radio astronomy and radar astronomy observations.
Variation in Water Content in Martian Subsurface Along Curiosity's Traverse
Phobos: Facts About Martian Moon
NASA's Mars Reconnaissance Orbiter took this image of the larger of Mars' two moons, Phobos, from a distance of about 6,800 km (about 4,200 miles).
CREDIT: NASA/JPL/University of Arizona
CREDIT: NASA/JPL/University of Arizona
Facts about Phobos:
- Radius of moon: 6.9 miles (11.1 km)
- Semi-major axis around Mars (distance from planet's center): 5,826 miles (9,376 km)
- Closest approach: 5,738 miles (9,234 km)
- Farthest approach: 5,914 miles (9,518 km)
- Orbit eccentricity: 0.0151
- Orbit inclination: 1.075 degrees
- Time to make one orbit: 7.65 hours
- Mass: 1.0659 x 10^16 kg
- Density: 1.872 g/cm^3
- Surface gravity: 0.0057m/s^2
- Escape velocity: 25 mph (41 km/h)
Hubble Digs Up Galactic Glow Worm
This charming and bright galaxy, known as IRAS 23436+5257, was captured by the NASA/ESA Hubble Space Telescope. It is located in the northern constellation of Cassiopeia, which is named after an arrogant, vain, and yet beautiful mythical queen.
Friday, March 22, 2013
What is Deep Space Network?
Q 220: Question of the Day - 22 March 2013 (Week 12)
What is Deep Space Network?
What is Deep Space Network?
Answer To Question 219
A219: The Death Star Theory refers to the fact that mass extinctions are periodic, and may be caused by the Earth's passing through a cloud of comets (the Oort cloud) every 26 million years. Some people have hypothesized that there is a yet-to-be-discovered dark star or perhaps a planet (called, appropriately enough, Nemesis) orbiting in the outer reaches of our solar system. This body disrupts the Oort cloud (once every 26 million years), sending comets into the inner parts of the solar system, some of which hit Earth and cause mass extinctions.
Voyager 1 left the solar system
"The Voyager team is aware of reports today that NASA's Voyager 1 has left the solar system," said Edward Stone, Voyager project scientist based at the California Institute of Technology, Pasadena, Calif. "It is the consensus of the Voyager science team that Voyager 1 has not yet left the solar system or reached interstellar space. In December 2012, the Voyager science team reported that Voyager 1 is within a new region called 'the magnetic highway' where energetic particles changed dramatically. A change in the direction of the magnetic field is the last critical indicator of reaching interstellar space and that change of direction has not yet been observed."
Curiosity Rover Exits 'Safe Mode'
Mars rover Curiosity has returned to active status and is on track to resume science investigations, following two days in a precautionary standby status, "safe mode."
Next steps will include checking the rover's active computer, the B-side computer, by commanding a preliminary free-space move of the arm. The B-side computer was provided information last week about the position of the robotic arm, which was last moved by the redundant A-side computer.
Mars solar Conjunction
This diagram illustrates the positions of Mars, Earth and the sun during a period that occurs approximately every 26 months, when Mars passes almost directly behind the sun from Earth's perspective. This arrangement, and the period during which it occurs, is called Mars solar conjunction. Radio transmissions between the two planets during conjunction are at risk of being corrupted by the sun's interference, so NASA Mars missions have a moratorium on sending commands to spacecraft on the surface of Mars or in orbit around Mars. Image credit: NASA/JPL-Caltech
Peculiar Features in Patterns of Ancient Light
The Planck mission has imaged the oldest light in our universe, called the cosmic microwave background, with unprecedented precision. The results fit well with what we know about the universe and its basic traits, but some unexplained features are observed.
Best Map Ever of the Universe
This map shows the oldest light in our universe, as detected with the greatest precision yet by the Planck mission. The ancient light, called the cosmic microwave background, was imprinted on the sky when the universe was 370,000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today.
Wednesday, March 20, 2013
What is Death Star Theory?
Q 219: Question of the Day - 20 March 2013 (Week 12)
What is Death Star Theory?
What is Death Star Theory?
Answer To Question 218
A218: Dark adaptation consists of the physical and chemical changes in your eyes that allow them to see well in the dark. Physically, the pupils of the eyes open wider (this happens quickly); chemically, slower changes occur in the eyes (which takes 10-20 minutes). It takes about 20 minutes for your eyes to completely adapt to darkness. Once your eyes become accustomed to the dark, even a momentary flash of white light can ruin it and your eyes will have to adapt all over again.
Earthrise" as seen in 1966
A five-year effort to recover nearly 50-year-old images of the moon is seeking public support to keep the project going.
Infant Stars Peek Out from Dusty Cradles
Astronomers have found some of the youngest stars ever seen thanks to the Herschel space observatory, a European Space Agency mission with important NASA contributions. Dense envelopes of gas and dust surround the fledging stars known as protostars, making their detection difficult until now. The discovery gives scientists a window into the earliest and least understood phases of star formation.
The new results come from the Herschel Orion Protostar Survey (HOPS), led by the University of Toledo. HOPS has looked at the vast stellar nursery in the Orion Molecular Cloud Complex, the biggest site of star formation near our solar system, located in the constellation of Orion.
Curiosity Casts Mastcam Magic On Mount Sharp
This cool space wallpaper is a mosaic of images from the Mast Camera (Mastcam) on NASA's Mars rover Curiosity, which shows Mount Sharp in a white-balanced color adjustment that makes the sky look overly blue but shows the terrain as if under Earth-like lighting. The component images were taken during the 45th Martian day, or sol, of Curiosity's mission on Mars (Sept. 20, 2012). Image released March 15, 2013.
Tuesday, March 19, 2013
What is Dark Adaptation?
Q 218: Question of the Day - 19 March 2013 (Week 12)
What is Dark Adaptation?
What is Dark Adaptation?
Answer To Question 217
A 217: The brightness ratio is a comparison of the brightness of two celestial objects (like stars or planets). The brightness ratio is defined as 2.512 raised to the difference of the magnitudes of the objects (since the magnitude scale is logarithmic and the difference in each successive magnitude is a factor of about 2.512 times). For example, a 1st magnitude star is 2.512 times brighter than a 2nd magnitude star (their brightness ration is 2.512). For another example, if two objects have magnitudes of 2 and 7 (a difference of 5), their brightness ratio is 2.512 raised to the 5th power, which is about 100.
NASA's Swift, Chandra Explore a Youthful 'Star Wreck'
A wider view places G306.3–0.9 in context with star-formation regions in southern Centaurus. Chandra X-ray observations (blue), Spitzer infrared data (red, cyan), and radio observations (purple) from the Australia Telescope Compact Array are merged in this composite. The image is one degree across, which corresponds to 450 light-years at the remnant's estimated distance. Credit: X-ray: NASA/CXC/Univ. of Michigan/M. Reynolds et al; Infrared: NASA/JPL-Caltech; Radio: CSIRO/ATNF/ATCA
Earth-Directed Coronal Mass Ejection From the Sun
The ESA and NASA Solar Heliospheric Observatory (SOHO) captured these images of the sun spitting out a coronal mass ejection (CME) on March 15, 2013, from 3:24 to 4:00 a.m. EDT. This type of image is known as a coronagraph, since a disk is placed over the sun to better see the dimmer atmosphere around it, called the corona. Credit:ESA&NASA/SOHO
Hubble Gazes on One Ring to Rule Them All
Galaxies can take many forms — elliptical blobs, swirling spiral arms, bulges, and disks are all known components of the wide range of galaxies we have observed using telescopes like the NASA/ESA Hubble Space Telescope. However, some of the more intriguing objects in the sky around us include ring galaxies like the one pictured above — Zw II 28.
Kepler Supernova Remnant
This is the remnant of Kepler's supernova, the famous explosion that was discovered by Johannes Kepler in 1604. The red, green and blue colors show low, intermediate and high energy X-rays observed with NASA’s Chandra X-ray Observatory, and the star field is from the Digitized Sky Survey. Hydration Map, Based on Mastcam Spectra, for 'Knorr' Rock Target
On this image of the rock target "Knorr," color coding maps the amount of mineral hydration indicated by a ratio of near-infrared reflectance intensities measured by the Mast Camera (Mastcam) on NASA's Mars rover Curiosity. The color scale on the right shows the assignment of colors for relative strength of the calculated signal for hydration. The map shows that the stronger signals for hydration are associated with pale veins and light-toned nodules in the rock. This image and the data for assessing hydration come from a Mastcam observation of Knorr during the 133rd Martian day, or sol, of Curiosity's work on Mars (Dec. 20, 2012). The width of the area shown in the image is about 10 inches (25 centimeters).
Image credit: NASA/JPL-Caltech/MSSS/ASU
Monday, March 18, 2013
What is Brightness Ratio?
Q 217: Question of the Day - 18 March 2013 (Week 12)
What is Brightness Ratio?
What is Brightness Ratio?
Answer To Question 216
A 216: A bolometer is an instrument that measures the total amount of radiant energy (not just visible light) received from a star or other celestial object.
Orion Molecular cloud
Parts of the Orion Molecular cloud are illuminated by nearby stars and therefore glow an eerie green color. The jets punch through the cloud and can be seen as a multitude of tiny pink-purple arcs, knots and filaments.
Friday, March 15, 2013
Answer To Question 215
A215: B-type stars are very hot and blue; they burn helium. Temperatures of B-type stars range from 11,000 - 25,000 K. Their mass averages 18 times the mass of the Sun and the average luminosity is 20,000 times that of the Sun. Examples include Rigel, Spica, and Regulus.
Orbits of Potentially Hazardous Asteroids
Credit: NASA/JPL-Caltech
This diagram illustrates the differences between orbits of a typical near-Earth asteroid (blue) and a potentially hazardous asteroid, or PHA (orange). PHAs have the closest orbits to Earth's orbit, coming within 5 million miles (about 8 million kilometers), and they are large enough to survive passage through Earth's atmosphere and cause significant damage.
Vortices Bump into a Hot Spot in Jupiter's Atmosphere.
In this series of images from NASA's Cassini spacecraft, a dark, rectangular hot spot (top) interacts with a line of vortices that approaches from on the upper-right side (second panel). The interaction distorts the shape of the hot spot (third panel), leaving it diminished (bottom). The black scale bar is about 6,200 miles (10,000 kilometers) wide, or about twice as wide as the United States.
Peering Deep into Jupiter's Atmosphere
The dark hot spot in this false-color image from NASA's Cassini spacecraft is a window deep into Jupiter's atmosphere. All around it are layers of higher clouds, with colors indicating which layer of the atmosphere the clouds are in. The bluish clouds to the right are in the upper troposphere, or perhaps higher still, in the stratosphere. The reddish gyre under the hot spot to the right and the large reddish plume at its lower left are in the lower troposphere. In addition, a high, gauzy haze covers part of the frame. An annotated version of this image highlights the hot spot in the middle with an arrow and boxes around the plume and the gyre.
Thursday, March 14, 2013
What are the B-Type Star?
Q 215: Question of the Day - 14 March 2013 (Week 11)
What are the B-Type Star?
What are the B-Type Star?
Answer To Question 214
A bolide is a meteor, asteroid, or comet that hits the Earth (or other planet or moon) and explodes.
Moon and Comet Pan-STARRS Over Las Vegas
CREDIT: Tyler Leavitt
Sun Spits Out Two CMEs
The sun recently erupted with two coronal mass ejections (CMEs). One began at 8:36 p.m. EDT on March 12, 2013 and is directed toward three NASA spacecraft, Spitzer, Kepler and Epoxi. There is, however, no particle radiation associated with this event, which is what would normally concern operators of interplanetary spacecraft since the particles can trip computer electronics on board. A second CME began at 6:54 a.m. EDT on March 13, 2013 and its flank may pass by Earth at a speed that does not typically have a significant impact at Earth.
Minerals at 'Rocknest' and 'John Klein'
This side-by-side comparison shows the X-ray diffraction patterns of two different samples collected from the Martian surface by NASA's Curiosity rover. These images, made from data obtained by Curiosity's Chemistry and Mineralogy instrument (CheMin), show the patterns obtained from a drift of windblown dust and sand called "Rocknest" and from a powdered rock sample drilled from the "John Klein" bedrock.
Wednesday, March 13, 2013
Answer To Question 213
Q213: A blue giant is a huge, very hot, very luminous, blue star. It is not a main sequence star but a post-main-sequence star. These incredibly hot stars burn helium. These giants have the spectral type O or B and are very rare and very bright. Blue giants have at least 18 times the mass of the Sun. Examples include Rigel and Regulus.
James Webb Telescope Model at South by Southwest
As big as a tennis court and as tall as a four-story building, a full-scale model of the James Webb Space Telescope model was on display from March 8-10 at the South by Southwest Interactive Festival in Austin, Texas.
NASA’s SDO Observes Earth, Lunar Transits in Same Day
On March 2, 2013, NASA’s Solar Dynamics Observatory (SDO) entered its semiannual eclipse season, a period of three weeks when Earth blocks its view of the sun for a period of time each day. On March 11, however, SDO was treated to two transits. Earth blocked SDO’s view of the sun from about 2:15 to 3:45 a.m. EDT. Later in the same day, from around 7:30 to 8:45 a.m. EDT, the moon moved in front of the sun for a partial eclipse.
Two Different Aqueous Environments on Mars
This set of images compares rocks seen by NASA's Opportunity rover and Curiosity rover at two different parts of Mars. On the left is " Wopmay" rock, in Endurance Crater, Meridiani Planum, as studied by the Opportunity rover. On the right are the rocks of the "Sheepbed" unit in Yellowknife Bay, in Gale Crater, as seen by Curiosity.
NASA Launches Exploration Design Challenge
The danger of space radiation is one of the biggest obstacles to the manned exploration of deep space, and NASA is hoping today's kids can help overcome it.
NASA has launched an exploration design challenge asking K-12 students around the world to help protect astronauts and spacecraft hardware from the high levels of space radiation they will experience beyond Earth's protective magnetosphere, the agency announced today (March 11).
"America's next step in human space exploration is an ambitious one and will require new technologies, including ways to keep our astronauts safe from the effects of deep-space radiation," NASA chief Charles Bolden said in a statement. "That is the focus of this challenge, and we are excited students will be helping us solve that problem."
Tuesday, March 12, 2013
What is Blue Giant Star?
Q213: Question of the Day - 12 March 2013 (Week 11)
What is Blue Giant Star?
What is Blue Giant Star?
Answer To Question 212
A212: A black dwarf is a small, very dense, cold, dead star. It is made mostly of carbon. This dark star is what remains after a red giant star loses its outer layers, forming a planetary nebula and then a white dwarf. The nuclear core of a black dwarf is depleted. Black dwarfs are about the size of the Earth (but tremendously heavier)! Our sun will someday turn into a black dwarf.
Blue Bursts of Hot Young Stars Captured by Hubble
This image, speckled with blue, white and yellow light, shows part of the spiral galaxy IC 5052. Surrounded in the image by foreground stars in our own galaxy, and distant galaxies beyond, it emits a bright blue-white glow which highlights its narrow, intricate structure. It is viewed side-on in the constellation of Pavo (The Peacock), in the southern sky.
Planetary Nebula NGC 5189
Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)
Portrait of a Rhea
This image was taken on March 10, 2013, and received on Earth March 10, 2013 by NASA's Cassini spacecraft. The camera was pointing toward Rhea at approximately 174,181 miles (280,317 kilometers) away, and the image was taken using the CL1 and CL2 filters. This image has not been validated or calibrated.
Image credit: NASA/JPL/Space Science Institute
Two Brown Dwarfs in Our Backyard
WISE J104915.57-531906 is at the center of the larger image, which was taken by the NASA's Wide-field Infrared Survey Explorer (WISE). This is the closest star system discovered since 1916, and the third closest to our sun. It is 6.5 light-years away.
Monday, March 11, 2013
Answer To Question 211
A211: A black body is an idealized body that is a perfect radiator and perfect absorber of electromagnetic radiation. A black body not only absorbs all wavelengths of energy and radiates at all wavelengths, but it does this at the maximum possible intensity for any given temperature. It doesn't necessarily look black. A star is a good approximation to a black body since stellar gases are very good absorbers of energy.
Space Debris Desert Dropdown
On 21 January 2001, a Delta 2 third stage, known as a PAM-D (Payload Assist Module - Delta), reentered the atmosphere over the Middle East. The titanium motor casing of the PAM-D, weighing about 70 kg, landed in Saudi Arabia about 240 km from the capital of Riyadh.
Comet PANSTARRS Rising Now
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Comets visible to the naked eye are a rare delicacy in the celestial smorgasbord of objects in the nighttime sky. Scientists estimate that the opportunity to see one of these icy dirtballs advertising their cosmic presence so brilliantly they can be seen without the aid of a telescope or binoculars happens only once every five to 10 years. That said, there may be two naked-eye comets available for your viewing pleasure this year.
Saturday, March 9, 2013
Abell 68
Credit: NASA & ESA. Acknowledgement: N. Rose
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