China Orbits New Remote-Sensing Satellite

File image.

by Staff Writers
Beijing, China (RIA Novosti) Aug 12, 2010
China put into orbit on Tuesday another remote sensing satellite, China's Xinhua news agency reported. The Yaogan X was launched aboard a Long March 4C carrier rocket from the Taiyuan Satellite Launch Center in northern Shanxi Province.

According to Xinhua, the satellite will be used primarily for scientific

experiments, land survey, crop yield assessment, and disaster monitoring.

Western experts believe, though, that this class of satellites could be used for reconnaissance and other military purposes.

The previous satellite in the series, Yaogan IX, was launched from the Jiuquan Satellite Launch Center in northwestern Gansu Province on March 5.

China, which has unveiled comprehensive space exploration plans, launched its first Yaogan class satellite in 2006.

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Discovery Of Saturn's Auroral Heartbeat

Saturn's ultraviolet auroras are visible over each pole in this image obtained in 2009 using the Advanced Camera for Surveys onboard the NASA/ESA Hubble Space Telescope. CREDIT: Jonathan Nichols, NASA, ESA, University of Leicester.

by Staff Writers
Leicester, UK (SPX) Aug 05, 2010
An international team of scientists led by Dr Jonathan Nichols of the University of Leicester has discovered that Saturn's aurora, an ethereal ultraviolet glow which illuminates Saturn's upper atmosphere near the poles, pulses roughly once per Saturnian day.

The length of a Saturnian day has been under much discussion since it was discovered that the traditional 'clock' used to measure the rotation period of Saturn, a gas giant planet with no solid surface for reference, apparently does not keep good time.

Saturn, like all magnetised planets, emits radio waves into space from the polar regions. These radio emissions pulse with a period near to 11 h, and the timing of the pulses was originally, during the Voyager era, thought to represent the rotation of the planet.

However, over the years the period of the pulsing of the radio emissions has varied, and since the rotation of a planet cannot be easily sped up or slowed down, the hunt for the source of the varying radio period has become one of the most perplexing puzzles in planetary science.

Now, in a paper to be published in Geophysical

Research Letters, Nichols et al. use images from the NASA/ESA Hubble Space Telescope of Saturn's auroras obtained between 2005-2009 to show that, not only do the radio emissions pulse, but the auroras beat in tandem with the radio.

Dr Nichols said: "This is an important discovery for two reasons. First, it provides a long-suspected but hitherto missing link between the radio and auroral emissions, and second, it adds a critical tool in diagnosing the cause of Saturn's irregular heartbeat."

Auroras, more commonly known as the "northern lights" on Earth, are caused when charged particles in space are funnelled along a planet's magnetic field into the planet's upper atmosphere near the poles, whereupon they impact the atmospheric particles and cause them to glow.

This happens when a planet's magnetic field is stressed by, for example, the buffeting from the stream of particles emitted by the Sun, or when moons such as Enceladus or Io expel material into the near-planet space.

Saturn's radio waves were long suspected to be emitted by the charged particles as they hurtle toward the poles, but no radio-like pulsing had been observed in Saturn's aurora, an enigmatic disconnect between the two supposedly-related phenomena.

However, Nichols et al. found that by using the clock of the radio pulsing to organise the auroral data, and stacking the results from all the Hubble Saturn auroral images obtained from 2005-2009 on top of each other, the auroral pulsing finally revealed itself.

Dr Nichols added: "This confirms that the auroras and the radio emissions are indeed physically associated, as suspected. This link is important, since it implies that the pulsing of the radio emissions is being imparted by the processes driving Saturn's aurora, which in turn can be studied by the NASA/ESA spacecraft Cassini, presently in orbit around Saturn. It thus takes us a significant step toward solving the mystery of the variable radio period."

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M-Class Solar Flare Erupts

Credit: NASA/SDO

by Staff Writers
Washington DC (SPX) Aug 10, 2010
An M-class flare erupted in active sunspot region 1093, peaking at 1824 UTC on August 7, 2010. The eruption hurled a coronal mass ejection (CME) into space. NASA's Solar Dynamics Observatory observed the flare.

The CME is not fully directed toward Earth, but some of the plasma cloud may glance the magnetosphere between August 9 and August 10, causing a geomagnetic disturbance and possible aurora.

Scientists classify solar flares according to their x-ray brightness in the wavelength range 1 to 8 Angstroms.

There are 3 categories: X-class flares are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms.

M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth's polar regions.

Minor radiation storms sometimes follow M-class flares. Compared to X- and M-class, C-class flares are small with few noticeable consequences on Earth.

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NASA Instrument Tracks Pollution from Russian Fires

Side-by-side comparison of carbon monoxide pollution from the series of devastating wildfires burning across central and western Russia, as seen by the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft on July 21, 2010 (left) and Aug. 1, 2010 (right). The AIRS data show the abundance of carbon monoxide present in the atmosphere at an altitude of 5.5 kilometers (18,000 feet). Image credit: NASA/JPL/Leonid Yurganov, University of Maryland, Baltimore County › Larger view

August 07, 2010

Drought and the worst heat wave Russia has seen in 130 years have sparked a devastating outbreak of wildfires across the nation this summer, primarily in the country's western and central regions. According to wire service reports and Russia's Emergency Situations Ministry, as of Aug. 6, 2010, some 558 fires were burning. The fires have killed at least 52 people, destroyed some 2,000 homes and charred more than 1,796 square kilometers (693 square miles). Russia's capital city of Moscow is currently blanketed in a thick smog, which has curtailed activities and disrupted air traffic. According to the Associated Press, levels of carbon monoxide pollution in Moscow are at an all-time high, four times higher than normal.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft is tracking the concentration and transport of carbon monoxide from the Russian fires. The figures presented here show the abundance of carbon monoxide present in the atmosphere at an altitude of 5.5 kilometers (18,000 feet). AIRS is sensitive to carbon monoxide in the mid-troposphere at heights between 2 and 10 kilometers (1.2 and 6.2 miles), with a peak sensitivity at an altitude of approximately 5 kilometers (3.1 miles). This region of Earth's atmosphere is also conducive to the long-range transport of the pollution that is lofted to this altitude.

As shown in Figure 1, acquired July 21, 2010, the concentration of carbon monoxide from the fires on that date was largely limited to the European part of Russia (western and central Russia). This contrasts dramatically with the data in Figure 2, acquired on August 1, when the carbon monoxide concentration was much higher and the area of the fires had increased significantly. The concentration of carbon monoxide is continuing to grow. According to Aug. 4 NASA estimates, the smoke plume from the fires spans about 3,000 kilometers (1,860 miles) from east to west, approximately the distance from San Francisco to Chicago.

Figure 3 shows changes in the total amount of carbon monoxide above western Russia in megatons through August 1, 2010 (shown by the red curve). The changes are plotted again the base year of 2009, which saw normal levels of seasonal carbon monoxide. This is contrasted against the year 2002, when peat fires predominated in Russia. The 2002 data are from the Measurements of Pollution in the Troposphere (MOPITT) instrument on NASA's Terra spacecraft. On August 1, 2010, the excess carbon monoxide content almost reached the maximum values seen in 2002. The rate of growth (approximately 0.7 megatons, or 700,000 metric tons, per day) characterizes the rate of emission; the current rate is approximately three times higher than in 2002.

AIRS is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena. More information about AIRS can be found at http://airs.jpl.nasa.gov.

www.jpl.nasa.gov

Smoke over Moscow

Fires continued burning around Moscow on August 7, 2010, forcing airports to delay flights, and prompting locals to stay indoors or venture out only with gauze masks, Bloomberg reported. Carbon monoxide levels in the capital city were several times the maximum allowable limit. Meanwhile, firefighters fought 577 fires covering 193,516 hectares (747 square miles).

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image on August 7. Red outlines indicate actively burning fires, and multiple fires cluster east of Moscow, many of them sending their smoke right over the city. Smoke almost completely hides the land surface throughout this scene.

High temperatures contributed to tinder-dry conditions along the Volga River, and Bloomberg reported that temperatures as high as 42 degrees Celsius (108 degrees Fahrenheit) would continue to plague central Russia for at least another day.

earthobservatory.nasa.gov

How To See The Best Meteor Showers Of The Year

A Geminid meteor. Image credit: Jimmy Westlake

by Staff Writers
Pasadena CA (JPL) Aug 09, 2010
There are several major meteor showers to enjoy every year at various times, with some more active than others. For example, April's Lyrids are expected to produce about 15 meteors an hour at their peak for observers viewing in good conditions.

Now, if you put the same observer in the same good conditions during a higher-rate shower like August's Perseids or December's Geminids, that person could witness up to 80 meteors an hour during peak activity.

Whether you're watching from a downtown area or the dark countryside, here are some tips to help you enjoy these celestial shows of shooting stars. Those streaks of light are really caused by tiny specks of comet-stuff hitting Earth's atmosphere at very high speed and disintegrating in flashes of light.

First a word about the moon - it is not the meteor watcher's friend. Light reflecting off a bright moon can be just as detrimental to good meteor viewing as those bright lights of the big city. There is nothing you can do except howl at the moon, so you'll have to put up with it or wait until the next favorable shower.

However, even though the 2010 Perseids and Geminids share the night sky with the moon, they are still expected to produce more visible meteor activity than other major showers that don't have an interfering moon.

The best thing you can do to maximize the number of meteors you'll see is to get as far away from urban light pollution as possible and find a location with a clear, unclouded view of the night sky.

If you enjoy camping, try planning a trip that coincides with dates of one of the meteor showers listed below. Once you get to your viewing location, search for the darkest patch of sky you can find, as meteors can appear anywhere overhead.

The meteors will always travel in a path away from the constellation for which the shower is named. This apparent point of origin is called the "radiant." For example, meteors during a Leonid meteor shower will appear to originate from the constellation Leo.

Whether viewing from your front porch or a mountaintop, be sure to dress for success. This means clothing appropriate for cold overnight temperatures, which might include mittens or gloves, and blankets. This will enable you to settle in without having to abandon the meteor-watching because your fingers are starting to turn colors.

Next, bring something comfortable on which to sit or lie down. While Mother Nature can put on a magnificent celestial display, meteor showers rarely approach anything on the scale of a July 4th fireworks show. Plan to be patient and watch for at least half an hour. A reclining chair or ground pad will make it far more comfortable to keep your gaze on the night sky.

Lastly, put away the telescope or binoculars. Using either reduces the amount of sky you can see at one time, lowering the odds that you'll see anything but darkness. Instead, let your eyes hang loose and don't look in any one specific spot. Relaxed eyes will quickly zone in on any movement up above, and you'll be able to spot more meteors.

Avoid looking at your cell phone or any other light. Both destroy night vision. If you have to look at something on Earth, use a red light. Some flashlights have handy interchangeable filters. If you don't have one of those, you can always paint the clear filter with red fingernail polish.

The meteor showers listed below will provide casual meteor observers with the most bang for their buck. They are the easiest to observe and most active. All these showers are best enjoyed in the hours after midnight. Be sure to also check the "Related Links" box for additional information, and for tools to help you determine how many meteors may be visible from your part of the world.

Major Meteor Showers (2010-2011)

Delta Aquarids
Comet of Origin: unknown Radiant: constellation Aquarius Active: July 14-Aug. 18, 2010 Peak Activity: No definite peak, but nights surrounding July 30 were predicted to be the best Peak Activity Meteor Count: Approximately 15 meteors per hour (Northern Hemisphere). Time of Optimal Viewing: An hour or two before dawn. Meteor watchers in the Southern Hemisphere and in the Northern Hemisphere's tropical latitudes enjoy the best views. Meteor Velocity: 42 kilometers per second (26 miles per second)

Perseids
Comet of Origin: 109P/Swift-Tuttle Radiant: constellation Perseus Active: Perseids begin to rise early August. Peak Activity: Aug. 12-13, 2010 Peak Activity Meteor Count: Approximately 50 meteors per hour Time of Optimal Viewing: Crescent moon will set early in the evening, allowing for dark skies all the way up until peak viewing just before dawn Meteor Velocity: 61 kilometers (38 miles) per second Note: The Perseid meteor shower is one of the most consistent performers and considered by many as 2010's best shower. The meteors they produce are among the brightest of all meteor showers.

Orionids
Comet of Origin: 1P/Halley Radiant: Just to the north of constellation Orion's bright star Betelgeuse Active: Oct. 4-Nov. 14, 2010 Peak Activity: Night of Oct. 22, but the light reflecting off an almost-full moon makes 2010 a less-than-spectacular year for one of Mother Nature's most spectacular showers. Peak Activity Meteor Count: Approximately 15 meteors per hour, if the sky is dark Time of Optimal Viewing: An hour or two before dawn Meteor Velocity: 68 kilometers (42 miles) per second Note: With the second-fastest entry velocity of the annual meteor showers, meteors from the Orionids produce yellow and green colors and have been known to produce an odd fireball from time to time.

Leonids
Comet of Origin: 55P/Tempel-Tuttle Radiant: constellation Leo Active: Nov. 7-28, 2010 Peak Activity: Night of Nov. 17-18, 2010 Peak Activity Meteor Count: Approximately 15 per hour Time of Optimal Viewing: A half-full moon sets after midnight, allowing for a dark sky. Best viewing time will be just before dawn. Meteor Velocity: 71 kilometers (44 miles) per second Note: The Leonids have not only produced some of the best meteor showers in history, but they have sometimes achieved the status of meteor storm. During a Leonid meteor storm, many thousands of meteors per hour can shoot across the sky. Scientists believe these storms recur in cycles of about 33 years, though the reason is unknown. The last documented Leonid meteor storm occurred in 2002.

Geminids
Comet of Origin: 3200 Phaethon Radiant: constellation Gemini Active: Dec. 4-16, 2010 Peak Activity: Night of Dec 13-14, 2010 Peak Activity Meteor Count: Approximately 50 meteors per hour Time of Optimal Viewing: 2 a.m. Meteor Velocity: 35 kilometers (22 miles) per second Note: Generally, the Geminids or August's Perseids provide the best meteor shower show of the year. Geminids are usually considered the best opportunity for younger viewers because the show gets going around 9 or 10 p.m. Unfortunately the moon does not set until after midnight this year, making for the possibility of drooping eyelids from the pre-teen set.

Quadrantids
Comet of Origin: 2003 EH1 Radiant: constellation Quadrant Murales Active: Dec. 28, 2010-Jan. 12, 2011 Peak Activity: Jan. 3-4, 2011 Peak Activity Meteor Count: Approximately 40 meteors per hour Time of Optimal Viewing: 2:30 a.m. to dawn Meteor Velocity: 41 kilometers (25.5 miles) per second Note: The alternate name for the Quadrantids is the Bootids. Constellation Quadrant Murales is now defunct, and the meteors appear to radiate from the modern constellation Bootes. Since the show is usually only a few hours long and often obscured by winter weather, it doesn't have the same celebrated status as the Geminids or Perseids.

Lyrids
Comet of Origin: C/1861 G1 Thatcher Radiant: constellation Lyra Active: April 16-25, 2011 Peak Activity: April 21-22, 2011 Peak Activity Meteor Count: 18-20 meteors per hour Time of Optimal Viewing: 11 p.m.-dawn Meteor Velocity: Lyrid meteors hit the atmosphere at a moderate speed of 48 kilometers (30 miles) per second. They often produce luminous dust trains observable for several seconds. Note: Light from the waning gibbous moon will degrade viewing

Eta Aquarids
Comet of Origin: 1P Halley Radiant: constellation Aquarius Active: April 19-May 28, 2011 Peak Activity: Early morning May 5-7, 2011 Peak Activity Meteor Count: Approximately 20 meteors per hour Time of Optimal Viewing: 3:30-5 a.m. Meteor Velocity: 66 kilometers (44 miles) per second.

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Three Planets Gather In Twilight

In the western sky at dusk, bright Venus lights the way to faint little Mars and Saturn. The crescent Moon joins them on August 12th and 13th. And can you spot Mercury far to their lower right? Binoculars help. Sky and Telescope illustration.

by Staff Writers
Washington DC (SPX) Aug 06, 2010
Step outside as evening twilight fades, and from now through the middle of August you'll find three planets shining low in the west - one much brighter than the other two. All you'll need is a clear sky and an open westward view about an hour after sunset.

"Venus will leap out at you," says Alan MacRobert, a senior editor of Sky and Telescope magazine. "Saturn and Mars are fainter, so you may need to wait for the sky to darken a bit more before they glimmer into view."

Venus is the famed "Evening Star," the brightest celestial object in Earth's sky after the Sun and Moon.

Saturn and Mars are only about 1 percent as bright. They form a more-or-less horizontal line above Venus, as wide as three or four fingers held together at arm's length. Saturn and Mars will spend the week sliding to the right with respect to Venus, creating a planetary triangle that changes shape from day to day.

Although the three planets look close together, they're not. Venus is currently 6 light-minutes (73 million miles) from us, Mars is 17 light-minutes (190 million miles) distant, and Saturn is far in the background 85 light-minutes (950 million miles) away.

Three reasons combine to make Venus shine so much brighter than the others. It's the closest to us, it's the closest to the Sun so it's illuminated more intensely, and it's covered with brilliantly reflective white clouds.

As for Mars and Saturn? They look similar in brightness for reasons that cancel out. Saturn is 35 times larger than Mars, but it's much farther both from us and from the Sun.

The crescent Moon joins the twilight planet scene on Thursday, August 12th (when it's below Venus) and Friday the 13th (when it's left of Venus).

"Don't miss this chance to do some easy astronomy from your backyard, balcony, or rooftop," says Sky and Telescope editor in chief Robert Naeye. "It's a big universe, and planets await!"

For more skywatching information and astronomy

news, visit SkyandTelescope.com or pick up Sky and Telescope, the essential magazine of astronomy since 1941.

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