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Perseid meteor shower: Coming soon to a sky near you – CSMonitor.com

Perseid meteor shower: Beloved by skywatchers, 2013 will be an excellent one for the Perseid meteor shower. The moon will set before midnight on the peak Perseids nights.

By Joe Rao, Space.com / July 27, 2013

7 27 13 perseid meteor full 300

7 27 13 perseid meteor full 300

NASA Astronaut Ron Garan, Expedition 28 flight engineer, tweeted this image from the International Space Station on Sunday Aug. 14 2011 with the following caption: “What a ‘Shooting Star’ looks like from space, taken yesterday during Perseid Meteor Shower.”

(AP Photo/Ron Garan – NASA)Between Aug. 3 and 15, there are no fewer than six different active minor displays. These sixmeteor showers are listed in the table below.

The actual number of meteors a single observer can see in an hour depends strongly on sky conditions, but the only equipment you’ll need to see them are your eyes and a modest amount of patience.

The rates given in the table are based on a limited star magnitude of +6.5 (considered to be the faintest star visible to the naked eye without the use of binoculars or atelescope), an experienced observer, and an assumption that the radiant is directly overhead.

The radiant is the place in the sky where the paths of meteors, if extended backward, would intersect when plotted on a star chart. Your clenched fist held at arm’s length is equal to roughly 10 degrees on the sky. So if the radiant is 30 degrees (“three-fists”) above the horizon, the hourly rate is halved; at 15 degrees, it is one-third.

While the hourly rates from these other meteor streams provide but a fraction of the numbers produced by the Perseids, combined, overall they provide a wide variety of meteors of differing colors, speeds and trajectories. Among these are the southern Delta Aquarids, which can produce faint, medium-speed meteors; the Alpha Capricornids, described as bright yellowish meteors and the Kappa Cygnids, which sometimes produce fireballs. As such, if you stay out and watch long enough, you may be nicely rewarded for your time spent.

Note that five of the six showers listed come from the region around the constellations of Aquarius and Capricornus. Theseconstellations are highest in the southern sky between roughly 1 a. m. and 3 a.m. Eastern time. The Kappa Cygnids appear to emanate from the constellation Cygnus, which will appear more or less overhead within an hour of local midnight.

Currently, the one drawback in watching for meteors is a bright gibbous moon, which this weekend will wane to last quarter on Sunday.

As Robert Lunsford of theAmerican Meteor Societypoints out, “the waning gibbous moon will rise later during the evening hours, but will still be in the sky during the more active morning hours, causing considerable interference with meteor viewing.”

After Sunday, the moon will diminish to a crescent phase, continuing to wane in both phase and brightness and will become significantly less of a hindrance to viewers as well as rising progressively later in the night. It will be new on Aug. 5.

(The above is an excerpt. The whole article can be read at the link below)



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Mars flooding: Ancient mega-flood on Red Planet revealed in 3D

Mars flooding: Ancient mega-flood on Red Planet revealed in 3D

Mars flooding: The discovery shows that a major underground channel generated by an ancient mega-flood is twice as deep as thought, and sheds light on how water shaped the surface of Mars, scientists added.

By Charles Q. Choi, SPACE.com / March 7, 2013

This image provided by NASA and taken by a camera aboard NASAs Mars Reconnaissance Orbiter shows the equatorial plains region known as Elysium Planitia on Mars. Using a radar instrument aboard the spacecraft, scientists made a 3-D map of flood channels below the surface of Mars, apparently created by past flooding. The findings were reported online, March 7, in the journal Science.



Radar scans of Mars have revealed the first 3D look at water-carved channels buried beneath the Red Planet’s surface, researchers say.

The discovery shows that a major underground channel generated by an ancient mega-flood is twice as deep as thought, and sheds light on how water shaped the surface of Mars, scientists added.

Mars today is cold and dry, with most of its water locked in polar ice caps, and researchers think its surface has been largely barren for the past 2.5 billion years. However, channels crisscrossing its surface hint that waters once flooded the Red Planet’s surface.

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The largest of the channels engraved into Mars within the past 500 million years belong to the 600-mile-long (1,000 kilometer) Marte Vallis system. Probing Marte Vallis could offer hints on a time otherwise thought of as cold and dry. [The Search for Water on Mars (Photos)]

However, Marte Vallis lies in Elysium Planitia, an expanse of plains along the Martian equator. This area is the youngest volcanic region on Mars, and massive volcanism throughout the past several hundred million years has covered most of its surface with lava, burying evidence of its recent history, including the source and most of the length of Marte Vallis.

Now, using the shallow radar onboard the Mars Reconnaissance Orbiter, scientists have scanned beneath the surface of Elysium Planitia. Their data helped generate a 3D reconstruction of Marte Vallis, revealing many details that lava flows buried long ago.

“This is the first time we’ve been able to see buried flood channels on a planet other than the Earth,” lead study author Gareth Morgan, a geologist at the Smithsonian’s National Air and Space Museum, told SPACE.com.

The researchers found the channels of Marte Vallis were at least 230 feet (70 meters) deep, making them at least twice as deep as thought.

“That shows previous ideas of erosion, of how much water have gone through Marte Vallis, have been underestimated,” Morgan said. “There was more significant flooding than before thought, and it’s interesting to think of where this water might have come from during this relatively dry period.”

By mapping the buried channels, researchers discovered the ancient gigantic floods that probably created Marte Vallis apparently originated deep underground from a now-buried portion of fissures known as Cerberus Fossae.

“The source of the floodwaters suggests they originated from a deep groundwater reservoir and may have been released by local tectonic or volcanic activity,” Morgan said.

Marte Vallis is similar to more ancient systems of channels on Mars. The gargantuan floods that generated these channels may also have briefly radically changed the Red Planet’s climate just as giant floods of Arctic water have on Earth. Learning more about Martian floods could provide information on key parts of that world’s history, researchers said.

“There’s also evidence of channels buried by lava or other sorts of materials in other areas on Mars, and we’d like to apply the same sort of radar studies to those,” Morgan said.

The scientists detailed their findings online today (March 7) in the journal Science.

Follow us @Spacedotcom, Facebook or Google+. Original article on SPACE.com.