Keep looking at
the cosmos as we see the Astronomy Pictures of the Day for the week of January
26. There’s plenty to see whether it’s a galaxy or a view from the Kennedy
Space Center or Finland. Open up a panoramic image to see a band of the Milky
Way without having to travel to South America.
Sunday, January 26
Explanation: It was a quiet
day on the Sun. The above image
shows, however, that even during off days the Sun's surface is a busy
place. Shown in ultraviolet
light, the relatively cool
dark regions have temperatures of thousands of degrees Celsius. Large sunspot group AR 9169
from the last solar cycle
is visible as the bright area near the horizon. The bright glowing gas flowing around the sunspots has a temperature
of over one million degrees Celsius.
The reason for the high temperatures is unknown but thought to be
related to the rapidly changing magnetic field
loops that channel solar plasma. Large sunspot group AR 9169 moved
across the Sun during 2000
September and decayed in a few weeks.
Monday, January 27
Explanation: There is a road
that connects the Northern to
the Southern Cross
but you have to be at the right place and time to see it. The road, as pictured
above, is actually the central band of our Milky Way Galaxy; the right place,
in this case, is dark Laguna
Cejar in Salar de
Atacama of Northern Chile;
and the right time was in early October, just after sunset. Many sky wonders
were captured then, including the bright Moon, inside the Milky Way arch; Venus, just above the Moon; Saturn and Mercury, just below the
Moon; the Large and Small Magellanic Clouds satellite galaxies, on the far
left; red airglow near
the horizon on the image left; and the lights of small towns at several
locations across the horizon.
One might guess that composing this
30-image panorama would have been a serene experience, but for that one
would have required earplugs to ignore the continued brays of wild donkeys.
Tuesday, January 28
Spiral Galaxy M83: The Southern
Pinwheel
Image Credit: NASA, ESA, Hubble Heritage Team (STScI/AURA), and W. P. Blair (JHU) et al.
Image Credit: NASA, ESA, Hubble Heritage Team (STScI/AURA), and W. P. Blair (JHU) et al.
Explanation: M83 is one of the closest
and brightest spiral
galaxies on the sky.
Visible with binoculars in the constellation of Hydra,
majestic spiral arms have prompted its nickname as the Southern Pinwheel.
Although discovered 250 years ago, only much later was
it appreciated that M83 was not
a nearby gas cloud, but a barred spiral galaxy
much like our own Milky Way
Galaxy. M83, pictured
above by the Hubble Space Telescope in a recently released image, is a
prominent member of a group of galaxies that includes Centaurus A and NGC 5253,
all of which lie about 15 million light years
distant. Several bright supernova
explosions have been recorded in M83. An intriguing double circumnuclear ring
has been discovered at the center of of M83.
Wednesday, January 29
Jelly Donut Shaped Rock Appears
on Mars
Image Credit: Mars Exploration Rover Mission, Cornell, JPL, NASA
Image Credit: Mars Exploration Rover Mission, Cornell, JPL, NASA
Explanation: What if a rock
that looked like a jelly donut suddenly appeared on Mars? That's just what
happened in front of the robotic
Opportunity rover currently exploring the red planet. The unexpectedly
placed rock, pictured
above, was imaged recently by Opportunity after not appearing in
other images taken as recently as twelve Martian days (sols) before.
Given the intriguing mystery, the leading explanation is somewhat tame
-- the rock was recently scattered by one of the rover's tires. Even so, the
rock's unusual light tones surrounding a red interior created interest in its composition -- as
well as causing it to be nicknamed Jelly Donut. A subsequent
chemical analysis
showed the rock has twice the abundance of manganese than any other rock yet
examined -- an unexpected clue that doesn't yet fit into humanity's
understanding of the Martian geologic
history. Opportunity, just
passing its 10th
anniversary on Mars,
continues to explore the Murray Ridge
section of the rim of 22-kilometer wide Endeavor Crater.
Thursday, January 30
Explanation: Fixed to a
tripod and looking east across the Kennedy Space Center's Turn Basin, a
camera captured these star trails as a series of short exposures over a
three hour period on the evening of January 23rd. Positioned just a few miles
from Space Launch Complex 41 at Cape Canaveral Air Force Station, it also
captured a spectacular night launch of an Atlas V rocket carrying NASA's Tracking and Data
Relay Satellite TDRS-L. Creating the trails, the apparent motion of the
stars through the sky is just a reflection of the daily rotation of planet
Earth on its axis. But that rotation is also the reason the rocket streak follows a path
arcing east across the Atlantic. Launching toward the
east, in the direction of Earth's rotation, adds the rotation velocity to the
rocket and reduces the fuel needed to reach orbit. A little ironically, TDRS-L
is destined for a geostationary
orbit. From there, 36,000 kilometers or so above the equator, its orbital
period will match Earth's rotation and the satellite will hang motionless in planet Earth's sky.
Friday, January 31
Explanation: Eerie pillars
of light ring the edges of this snowy little planet. Of course the little
planet is planet Earth, shown in a nadir-to-zenith, around-the-horizon, little planet
projection. The spherical panoramic image mosaic maps
a view from Siilinjärvi in eastern Finland. Flat ice crystals, like those
more often found in high,
thin clouds, are gently fluttering in very cold air near the surface. Pillars of light appear as
the crystals' briefly horizontal facets reflect upward directed light from
ground sources downward, toward the observer. In fact, the fluttering crystals
produce an effect analogous to shimmering columns of moonlight or sunlight reflected by
surface waves across water.
Saturday, February 1
Explanation: Fantastic shapes lurk in
clouds of glowing gas in NGC 6188, about 4,000 light-years away. The emission
nebula is found near the edge of a large molecular cloud unseen at visible
wavelengths, in the southern constellation Ara.
Massive, young stars of the
embedded Ara OB1
association were formed in that region only a few million years ago, sculpting the dark shapes
and powering the nebular glow with stellar winds and intense ultraviolet
radiation. The recent star formation
itself was likely triggered by winds and supernova explosions, from previous
generations of massive stars, that swept up and compressed the molecular gas.
Joining NGC 6188 on this cosmic canvas is rare emission nebula NGC 6164, also created by
one of the region's massive O-type stars. Similar in appearance to many planetary nebulae, NGC
6164's striking, symmetric gaseous shroud and faint halo surround its bright
central star near the bottom edge. The impressively wide field of
view spans over 3 degrees (six full Moons), corresponding to over 200 light
years at the estimated distance of NGC 6188. Narrowband
image data has been included in the natural looking color
composite, adding to deep red emission from hydrogen and sulfur atoms and
the blue-green light of oxygen atoms.
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