Have you ever seen an aurora?
Auroras are occurring again with increasing frequency.
With the Sun being
unusually dormant over the past four years, the amount of Sun-induced auroras has been unusually low.
More recently, however,
our Sun has become increasingly active and
exhibiting a greater abundance of
sunspots,
flares, and
coronal mass ejections.
Solar activity
like this
typically expels charged particles into the Solar System, some of which may trigger
Earthly auroras.
Two weeks ago, beyond trees and before stars, a solar storm precipitated the
above timelapse displays
of picturesque auroras above Ravnastua, Skoganvarre and
Lakselv,
Norway.
Curtains of auroral light, typically green,
flow,
shimmer and
dance as
energetic particles fall toward the Earth and
excite
air molecules high up in the Earth's atmosphere.
With solar maximum still in the future, there may be even better opportunities to see spectacular
auroras personally over the next few years.
This moon is shining by the light of its planet.
Specifically, a large portion of Enceladus
pictured above
is illuminated primarily by sunlight first reflected from the
planet Saturn.
The result is that the normally
snow-white moon appears in the gold color of
Saturn's cloud tops.
As most of the illumination comes from the image left, a
labyrinth of ridges throws notable shadows just to the right of the image center, while the kilometer-deep canyon
Labtayt Sulci is visible just below.
The bright thin crescent on the far right is the only part of
Enceladus
directly lit by the Sun.
The above image
was taken last year by the robotic
Cassini spacecraft during a close pass by by the enigmatic moon.
Inspection of the lower part of this digitally sharpened image reveals
plumes of ice
crystals thought to originate in a
below-surface sea.
In this image from late 2010, software engineers worked in the background as Glenn Research Center technician, Joe Kerka, rotated the SCaN Testbed flight enclosure assembly. The Space Communications and Navigation, or SCaN Testbed will be launched on a Japanese H–IIB Transfer Vehicle and installed on the International Space Station and will provide an on-orbit, adaptable software-defined radio facility with corresponding ground and operational systems. This will permit mission operators to remotely change the functionality of radio communications and offer the flexibility to adapt to new science opportunities and recover from anomalies within the science payload or communication system. This effort is sponsored by the SCaN Program as part of the , CoNNeCT, or Communications, Navigation, and Networking reConfigurable Testbed Project led by Glenn Research Center. The Glenn Research Center will host a media event at 10:30 am on Friday, Feb/. 10, to showcase the SCsN Testbed before it is shipped to Japan. Image Credit: NASA/Quentin L. Schwinn
Although you've surely seen it, you might not have noticed it.
During a cloudless twilight, just before
sunrise or after
sunset,
part of the atmosphere above the horizon appears
slightly off-color, slightly pink or orange.
Called the Belt of Venus, this off-color band between the dark
eclipsed sky and the
blue sky can be seen in nearly every direction
including that opposite the Sun.
Straight above, blue sky is normal sunlight reflecting off the atmosphere.
In the Belt of Venus, however, the
atmosphere reflects light from the setting (or rising)
Sun which appears more red.
Below the Belt of Venus,
the atmosphere appears more dark because no sunlight reaches it.
The Belt of Venus can be seen from any location with a
clear horizon.
Pictured above
last month over Mercedes,
Argentina, a panoramic vista featuring the Belt of Venus was digitally stitched together from 16 smaller images.
The belt is
frequently
caught
by
accident
in
other
photographs.
On Jan. 27, 2012, a large X-class flare erupted from an active region near the solar west limb. X-class flares are the most powerful of all solar events. Seen here is an image of the flare captured by the X-ray telescope on Hinode. This image shows an emission from plasma heated to greater than eight million degrees during the energy release process of the flare. Image Credit: JAXA/Hinode
What surrounds a hotbed of star formation?
In the case of the
Orion Nebula -- dust.
The
entire Orion field, located about 1600
light years away, is inundated with intricate and
picturesque filaments of dust.
Opaque to visible light,
dust is created in the outer atmosphere of massive
cool stars and expelled by a strong outer wind of particles.
The Trapezium and other forming star clusters are embedded in the nebula.
The intricate filaments of dust surrounding
M42 and
M43 appear brown in the
above image, while central glowing gas is highlighted in red.
Over the next few million years much of
Orion's dust will be slowly destroyed by the very stars now being formed, or dispersed into the Galaxy.
Our Moon's appearance changes nightly.
This time-lapse sequence shows
what our Moon looks like during a
lunation, a complete lunar cycle.
As the
Moon orbits the
Earth,
the half illuminated by the
Sun
first becomes increasingly visible,
then decreasingly visible.
The Moon
always keeps the same face toward the Earth.
The Moon's apparent size changes slightly, though,
and a slight wobble called a
libration is discernible as it progresses along its elliptical orbit.
During the
cycle, sunlight reflects from the
Moon
at different angles, and so illuminates different features differently.
A full
lunation takes about 29.5 days, just under a month
(moon-th).
Vital clues about the devastating ends to the lives of massive stars can be found by studying the aftermath of their explosions. In its more than twelve years of science operations, NASA's Chandra X-ray Observatory has studied many of these supernova remnants sprinkled across the galaxy. The latest example of this important investigation is Chandra's new image of the supernova remnant known as G350.1-0.3. This stellar debris field is located some 14,700 light years from the Earth toward the center of the Milky Way. Evidence from Chandra and from ESA's XMM-Newton telescope suggest that a compact object within G350.1+0.3 may be the dense core of the star that exploded. The position of this likely neutron star, seen by the arrow pointing to "neutron star" in the inset image, is well away from the center of the X-ray emission. If the supernova explosion occurred near the center of the X-ray emission then the neutron star must have received a powerful kick in the supernova explosion. Data suggest this supernova remnant, as it appears in the image, is 600 and 1,200 years old. If the estimated location of the explosion is correct, this means the neutron star has been moving at a speed of at least 3 million miles per hour since the explosion. Another intriguing aspect of G350.1-0.3 is its unusual shape. Many supernova remnants are nearly circular, but G350.1-0.3 is strikingly asymmetrical as seen in the Chandra data in this image (gold). Infrared data from NASA's Spitzer Space Telescope (light blue) also trace the morphology found by Chandra. Astronomers think that this bizarre shape is due to stellar debris field expanding into a nearby cloud of cold molecular gas. The age of 600-1,200 years puts the explosion that created G350.1-0.3 in the same time frame as other famous supernovas that formed the Crab and SN 1006 supernova remnants. However, it is unlikely that anyone on Earth would have seen the explosion because of the obscuring gas and dust that lies along our line of sight to the remnant. These results appeared in the April 10, 2011 issue of The Astrophysical Journal. Image Credits: X-ray: NASA/CXC/SAO/I. Lovchinsky et al; IR: NASA/JPL-Caltech
Sweeping slowly through the constellation Hercules,
Comet Garradd (C2009/P1) passed with about 0.5 degrees of
globular
star cluster M92 on February 3.
Captured here in its latest
Messier moment, the
steady performer remains just below naked-eye
visibility
with a central coma comparable in brightness to
the dense, well-known star cluster.
The rich telescopic view from New Mexico's,
early morning skies, also features Garradd's broad
fan shaped dust tail and a much narrower ion tail that
extends up and beyond the right edge of the frame.
Pushed out by the pressure of sunlight, the dust tail
tends to trail
the comet along its orbit while
the ion tail,
blown by the solar wind, streams away from the comet in
the direction opposite the Sun.
Of course, M92 is over 25,000 light-years away.
Comet Garradd is 12.5 light-minutes
from planet Earth, arcing above
the ecliptic plane.
In 1995, a now famous picture
from the Hubble Space Telescope featured
Pillars of Creation, star forming columns of cold gas and
dust light-years long inside
M16, the Eagle Nebula.
This remarkable false-color
composite
image revisits the nearby stellar nursery
with image data from the orbiting
Herschel Space Observatory and
XMM-Newton
telescopes.
Herschel's far infrared
detectors record the emission from
the region's cold dust directly, including the famous pillars
and other structures
near the center of the scene.
Toward the other extreme of the
electromagnetic spectrum, XMM-Newton's
X-ray
vision reveals the massive, hot stars of
the nebula's embedded star cluster.
Hidden from Hubble's view at optical wavelengths,
the massive stars have a profound effect,
sculpting and transforming the natal gas and dust
structures with their energetic winds and radiation.
In fact, the massive stars are short lived and astronomers
have found evidence
in the image data pointing to the remnant of a supernova explosion
with an apparent age of 6,000 years.
If true, the expanding shock waves would have
destroyed the visible structures, including the famous pillars.
But because the Eagle Nebula is some 6,500 light-years distant,
their destruction won't
be witnessed for hundreds of years.