10 Cool Images of Mars

Staring into the clear night sky, you see a bright light low in the west and realize that from at least 35 million to 250 million miles away depending on orbit, Mars awaits. Was it ever inhabited by life? What secrets does it hold that we hope it will give up? Some of this will be answered by the images and data collected by HiRISE.
Possible Active Dune Gullies

HiRISE stands for High Resolution Imaging Science Experiment, a coordinated project between NASA and the University of Arizona. It has produced
spectacular images of Mars for our enjoyment and helps researchers to explore the history of water on the planet.

In the top picture, Richardson Crater Dunes are partially defrosted and covered in seasonal carbon dioxide
frost. Dust devils have left their footprints and researchers think larger channels were caused by blocks of dry ice sliding down the dunes and going directly from a solid to a gas (sublimating). However they are caused, it is a stunning photograph
worthy of being at a museum of modern art.
Potential Future Mars Landing Site: Mounds in Acidalia Planitia

These mounds are "mud" volcanoes that occur when a mix of gas, ground rock and liquids deep under the earth's crust (from several meters to kilometers deeo) are forced up to the top. Scientists are looking at it as a potential future landing site because the sediments brought up might contain signs of microbiological past, or even better, present life.
Dark Rimless Pits in the Tharsis Region

These two pits in the Tharsis region align with two depressions of a dark wispy-like deposit. The larger one is 310 m wide while the smaller one is 180 m wide. The deposit itself has a large boomerang shape and scientists believe it consists of darker material blown out of the pits and scattered by the wind.
Frost-Covered Gullies

Gullies in a large crater in Terra Sirenum of the southern hemisphere of Mars are covered in winter frost. In the image, the frost is shown as bright spots and because it is facing south, it's believed to be water frost rather than frost caused by carbon dioxide (CO2). One of the big questions is whether or not the gullies are formed by water and if so, surface or substrate water, or are they formed by dry debris and CO2?
This stunning photo looks like a road alongside an ocean and in actuality may not be so far from that description, albeit Mars style. "Holden crater has some of the best-exposed lake deposits and ancient megabreccia known on Mars," said HiRISE’s principal investigator, professor Alfred McEwen of the UA’s Lunar and Planetary Laboratory. "Both contain minerals that formed in the presence of water and mark potentially habitable environments. This would be an excellent place to send a rover or sample-return mission to make major advances in understanding if Mars supported life."

Rocky Mesas of Nilosyrtis Mensae Region

Clay minerals
have been found in this area and scientists are excited at the idea of exploring it further. It may be difficult because an exploration vehicle like the Mars Rover would have to land further away and then make its way across the rocky mesas but it is hoped that it is possible.

Layers in Columbus Crater

The different levels of brightness in this image are most likely different sediments in the basin of the crater. This is an old impact crater and researchers believe that erosion from the rim of the crater (which is now much flatter than it was originally) deposited the sediments.

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Huge Solar Storm Triggers Amazing Auroras

Aurora Over Quebec
Photograph courtesy Ian Diamond
Auroras create green curtains of light August 4 over the Rupert River in Waskaganish (see map), a Cree Nation community in Quebec, Canada.
Last week's northern lights—which lasted a few days—were products of a large burst of plasma, or charged gas, from the sun known as a coronal mass ejection. A NASA orbiter called the Solar Dynamics Observatory saw last Sunday's eruption, which was aimed directly at Earth and sparked predictions of a shimmering sky show.
Now it seems aurora fans may be in for another treat: A solar flare spotted Saturday by NASA's Solar and Heliospheric Observatory was even more powerful than the previous eruption. Although this time the bulk of the plasma burst isn't aimed right at Earth, scientists say it could still trigger another round of colorful auroras.
Beach Aurora
Photograph courtesy Federico Buchbinder
An aurora created by last week's coronal mass ejection glimmers over Laurentian Beach, on the shores of Lake Manitoba in Canada (map), on August 6.
Auroras happen when energized particles from the sun wash over Earth and flow down the planet's magnetic field lines toward the Poles. Along the way, the charged partices bang into nitrogen, oxygen, and other atoms in our atmosphere.
The charged solar particles give Earth's atmospheric atoms an energy boost, which then gets released as light, producing the shimmering curtains of greens, reds, blues, and other colors. (Related: "Aurora 'Power Surges' Triggered by Magnetic Explosions.")
Purple Haze
Photograph courtesy Shawn Malone, LakeSuperiorPhoto.com
Seen from the shores of Lake Superior, an August 4 aurora glows green topped with blueish-purple. Auroras glow in different colors based on the types of atoms in the atmosphere and how high they are in the sky.
Humans mostly see auroras in shades of yellowish-green. That's because the eye sees a light show created by oxygen atoms at lower altitudes, about 62 to 186 miles (100 to 300 kilometers) above the surface.
Blues and purples are created by lighter gases such as hydrogen and helium, while low-level nitrogen can add red fringes to the bottoms of green auroral curtains.

Oslo Light Show
Photograph courtesy Otto L. Motzke
Green light curls over Oslo, Norway, August 4 in an auroral display caused by last Sunday's coronal mass ejection.
In the Northern Hemisphere, auroras are more commonly seen at high latitudes near the Arctic Circle, such as northern Alaska, Canada, and Scandinavia.
But scientists predicted that last Sunday's strong burst would bring the light show to slightly lower parts of the globe. In fact, sky-watchers were snapping pictures of auroras as far south as Oslo, Lake Manitoba in Canada, and Lake Superior (map) in the United States.
"Superior" Aurora
Photograph courtesy Shawn Malone, LakeSuperiorPhoto.com
The view from a Michigan shore of Lake Superior included multicolored auroras on August 3, as seen in a panoramic picture.
A solar storm headed for Earth isn't a guarantee of auroras. Without more sun-watching satellites, scientists are hard-pressed to know the exact effects a coronal mass ejection will have on Earth's atmosphere.
Last week Leon Golub of the Harvard-Smithsonian Center for Astrophysics had put the odds of the August 1 solar flare producing auroras at about 50-50.
Sky Glows Green
Photograph courtesy Miguel Yetman
Clouds over Manitoba, Canada, are bathed in green light from an August 4 aurora.
The solar ejections that cause auroras can also create geomagnetic storms that can affect spacewalking astronauts, Earth-orbiting satellites, and even communications and power systems on the ground.
But like the previous solar storm, which was strong but relatively slow, the oncoming burst of charged particles shouldn't create significant problems for people, according to the website SpaceWeather.com. Instead, the site says, "high-latitude sky-watchers should be alert for auroras when the cloud arrives, probably on August 10."
Green Glow, Orange Clouds
Photograph courtesy Tania A. Berntsen
Green aurora borealis curtains light up the skies over a beach in Grimstad, Norway (map), just after midnight on August 4.
The cloud of solar particles that sparked last week's northern lights weighed about a billion tons, according to NASA. The space agency's Solar Dynamics Observatory and other sun-studying spacecraft are about more than just advance notice of sky shows.
Because solar wind can disrupt communications systems and power grids, "one of the main reasons to have these instruments in space is so that you can issue alerts or warnings, pretty much like you would with a hurricane," Golub said.
That way "people can know ahead of time when there is a possibility of an event that will have an impact on Earth."
Solar Extreme
Image courtesy NASA
A bright swirl (left of center) on the sun marks the spot where a tumult of plasma sent out the August 1 coronal mass ejection that sparked last week's auroras, as seen in a mosaic picture taken by the Solar Dynamics Observatory. Different colors show regions of temperature variation on the sun.
Solar activity rises and falls on a regular cycle of about 11 years. The last period of peak activity ended in 2001, and it led into a long-lasting quiet spell. (See "Sun Oddly Quiet—Hints at Next 'Little Ice Age'?")
Along with a recent flurry of sunspots, the August eruptions seem to be signs of the star's reawakening—good news for aurora fans, but potential trouble for satellites, astronauts, and some Earthly technologies.

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