Posted on by VirtualAstro

Why Can We See Multiple ISS Passes Right Now?

Four ISS passes over the UK last night. Credit: Mark Humpage

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Last night in the UK, US and Europe, we were spoiled with multiple and bright ISS passes. Not just one or two, but up to six passes were able to be viewed throughout the evening in some locations.

This is quite rare as normally we get only one or maybe two visible passes in the evening or morning.

So why are we getting as many as four to six passes per night?

The ISS did receive an orbital boost and its altitude increased by around 20 kilometers. The orbital height of the ISS has an effect on how many visible passes there are at present in the Northern hemisphere. Another reason is because of the time of year.

We are only a week or so away from the Summer Solstice, the time of year when the Northern hemisphere receives the most hours of sunlight. Naturally this means we only have a few hours of darkness and the further North you go, the shorter the nights are and in some locations this time of year, it doesn’t ever get truly dark.

So why does this affect the ISS?

Basically the ISS visible passes have increased due to the station being illuminated much more by the Sun as there are more hours of sunlight right now, but the effect will wear off when we pass through Summer solstice and the nights get longer again.

Take advantage of this rare time and go outside and enjoy the ISS as much as you can in this series of visible passes.

Need to know how and when you can see the ISS? NASA has a Skywatch page where you can find your specific city to look for satellite sighting info.

Spaceweather.com, has a Satellite Tracker Tool. Just put in your zip code (good for the US and Canada) to find out what satellites will be flying over your house.

Heaven’s Above also has a city search, but also you can input your exact latitude and longitude for exact sighting information, helpful if you live out in the country.

Credit: Mark Humpage
Posted on by Nancy Atkinson

Astounding Satellite Views of the Puyehue-Cordón Ash Plume

A gigantic plume of ash from the Puyehue-Cordón Volcano in Chile spreads across South America. This image was taken on June 13, 2011 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite. Credit: NASA and courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC.

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An incredible amount of ash is being spewed from the erupting Puyehue-Cordón Volcano Complex in Chile. This image, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on June 13, 2011, shows a large plume of volcanic ash blowing about 780 kilometers east and then northeast over Argentina. A plume of volcanic ash from this eruption disrupted air traffic as far away as New Zealand on June 13. See images below of how far the ash has traveled in the atmosphere, a half a world away.


The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite acquired the two images below of the Chilean ash plume on June 13, 2011 showing that a concentrated plume was visible more than half a world away. The first image shows the ash plume over southern Australia and the Tasman Sea, while the second image provides a view farther east over New Zealand and the South Pacific Ocean.

The Chilean ash plume over southern Australia and the Tasman Sea on June 13, 2011. Credit: NASA/MODIS on the Aqua Satellite.
The Chilean volcano ash plume over NewZealand and the South Pacific Ocean. Credit: NASA/MODIS on the Aqua satellite.

NASA’s Earth Observatory website says that although the intensity of the eruption has decreased since the initial eruption, the volcano’s activity is holding steady. The plume reached between 4 and 8 kilometers in altitude on June 13, its height varying with the intensity of the eruptive episode throughout the day.

Here’s how the volcano looked back on June 4, 2011 when it began spewing ash 45,000 feet (14,000 meters) into the air. The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite captured this natural-color image shortly after the eruption began:

Chile’s Puyehue-Cordón Caulle volcano on June 4, 2011. Credit: NASA/Aqua - MODIS

See more images and data on this volcano at the NASA Earth Observatory Natural Hazards website.

You can follow Universe Today senior editor Nancy Atkinson on Twitter: @Nancy_A. Follow Universe Today for the latest space and astronomy news on Twitter @universetoday and on Facebook.

Posted on by Nancy Atkinson

Aquarius Satellite Launches to Observe Earth’s Oceans

A picture-perfect launch on a Delta II rocket from Vandeberg Air Force Base in California sent the newest satellite into orbit. The Aquarius/SAC-D spacecraft lifted off June 10, 2011 at 7:20 a.m. PDT (1420 UTC) to gather global measurements of ocean surface salinity, leading to a better understanding of ocean circulation, climate and Earth’s water cycle. NASA’s Aquarius instrument is part of the SAC-D spacecraft built by CONAE, Argentina’s space agency.

Continue reading “Aquarius Satellite Launches to Observe Earth’s Oceans”

Posted on by Nancy Atkinson

Joplin, Missouri Tornado Seen From Space

This video from NOAA’s GOES geostationary satellite shows the development of the supercell storm that produced the devastating tornado that struck Joplin, Missouri. Here you can see the storm develop over Missouri, Oklahoma, Kansas state lines on May 22, 2011 between 12:44pm to 7:15pm CDT. This was part of the great wave of severe storms that swept across the central United States, with tornado warnings from Minneapolis to Dallas. The most damaging storm struck Joplin at 5:30 pm local time (2230 UTC), killing at least 116 people.

Below is imagery from the Tropical Rainfall Measuring Mission satellite (TRMM).
Continue reading “Joplin, Missouri Tornado Seen From Space”

Posted on by VirtualAstro

Coming Soon – Night Shining Noctilucent Clouds

Noctilucent Cloud Display Credit: Adrian West

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Soon you may see an eerie spectacle on clear summer nights if you are located at latitudes between 50° and 70° north and south of the equator: Noctilucent Clouds.

These ghostly apparitions are a delight to see and are quite rare. It is incredibly difficult to predict exactly when they will appear, but we do know they should begin to appear soon.

The season for Noctilucent Clouds (Noctilucent = Latin for “Night Shining”) starts early June and continues into late July. They are seen just after dusk, or before dawn and an apparition can last around an hour.

These mysterious clouds, with their bizarre tenuous wispy shapes reminiscent of ripples in sand or the changing surface of a pool of water, spread like a glowing web across the northern sky. Colours can range from brilliant whites, with tinges of blue, pink and orange.

Formed by tiny ice crystals, they are the highest clouds in the Earth’s atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometers (47 to 53 miles) almost at the edge of space.

They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon, while the lower layers of the atmosphere are in the Earth’s shadow. Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon, only being recorded for about 120 years.

Noctilucent clouds can only form under very restrictive conditions, and their occurrence can be used as a guide to changes in the upper atmosphere. Since their relatively recent classification, the occurrence of noctilucent clouds appears to be increasing in frequency, brightness and extent.

There is evidence that the relatively recent appearance of noctilucent clouds and their gradual increase, may be linked to climate change. Another recent theory is that some of these bright displays come from particulates and water vapour in the atmosphere left over from Space Shuttle launches.

How can you see them? Over the next couple of months look north during dusk and dawn and try and spot this mysterious and elusive phenomenon. They are best seen when the sun is between 6 and 16 degrees below the horizon, and seem to occur more frequently in the Northern hemisphere than the Southern.

Good luck!

Noctilucent clouds over Blair, Nebraska, USA. Credit: Mike Hollingshead
Posted on by Nancy Atkinson

The View from 100,000 Feet

I love these student projects that send a camera via a balloon high in the atmosphere to film the view of Earth below. Here’s another from a group of German students who were able to film in HD from an altitude of more than 100,000 ft. (30,480 meters). Enjoy the music, too.

“Our challenge was to survive ambient air pressures as low as 1/100th of an atmosphere, temperatures as low as -60°C and finally to locate and recover the Camera,” Tobias Lohf wrote UT. “We had a HD-Cam, GPS tracker and a heating pad on board, and all the construction had a total weight of about 1kg.”

The rest of the team included Marcel Dierig, Tobias Stodieck, Tristan Eggers and Marvin Rissiek and they hope to inspire other students to try the same project. “All you need need is a camera, weather balloon and Duct Tape,” they said.

Posted on by Nancy Atkinson

New Satellite Will ‘Taste’ Earth’s Salty Seas from Orbit

Artist's concept of the Aquarius/SAC-D spacecraft, a collaboration between NASA and Argentina's space agency, with participation from Brazil, Canada, France and Italy. Aquarius, the NASA-built primary instrument on the spacecraft, will take NASA's first space-based measurements of ocean surface salinity, a key missing variable in satellite observations of Earth that links ocean circulation, the global balance of freshwater and climate. The mission is scheduled to launch in June. Image credit: NASA

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From a JPL press release:

Final preparations are under way for the June 9 launch of the international Aquarius/SAC-D observatory. The mission’s primary instrument, Aquarius, will study interactions between ocean circulation, the water cycle and climate by measuring ocean surface salinity.

Engineers at Vandenberg Air Force Base in California are performing final tests before mating Aquarius/SAC-D to its Delta II rocket. The mission is a collaboration between NASA and Argentina’s space agency, Comision Nacional de Actividades Espaciales (CONAE), with participation from Brazil, Canada, France and Italy. SAC stands for Satelite de Applicaciones Cientificas. Aquarius was built by NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and the agency’s Goddard Space Flight Center in Greenbelt, Md.

In addition to Aquarius, the observatory carries seven other instruments that will collect environmental data for a wide range of applications, including studies of natural hazards, air quality, land processes and epidemiology.

The mission will make NASA’s first space observations of the concentration of dissolved salt at the ocean surface. Aquarius’ observations will reveal how salinity variations influence ocean circulation, trace the path of freshwater around our planet, and help drive Earth’s climate. The ocean surface constantly exchanges water and heat with Earth’s atmosphere. Approximately 80 percent of the global water cycle that moves freshwater from the ocean to the atmosphere to the land and back to the ocean happens over the ocean.

Salinity plays a key role in these exchanges. By tracking changes in ocean surface salinity, Aquarius will monitor variations in the water cycle caused by evaporation and precipitation over the ocean, river runoff, and the freezing and melting of sea ice.

Salinity also makes seawater denser, causing it to sink, where it becomes part of deep, interconnected ocean currents. This deep ocean “conveyor belt” moves water masses and heat from the tropics to the polar regions, helping to regulate Earth’s climate.

“Salinity is the glue that bonds two major components of Earth’s complex climate system: ocean circulation and the global water cycle,” said Aquarius Principal Investigator Gary Lagerloef of Earth & Space Research in Seattle. “Aquarius will map global variations in salinity in unprecedented detail, leading to new discoveries that will improve our ability to predict future climate.”

Aquarius will measure salinity by sensing microwave emissions from the water’s surface with a radiometer instrument. These emissions can be used to indicate the saltiness of the surface water, after accounting for other environmental factors. Salinity levels in the open ocean vary by only about five parts per thousand, and small changes are important. Aquarius uses advanced technologies to detect changes in salinity as small as about two parts per 10,000, equivalent to a pinch (about one-eighth of a teaspoon) of salt in a gallon of water.

Aquarius will map the entire open ocean every seven days for at least three years from 408 miles (657 kilometers) above Earth. Its measurements will produce monthly estimates of ocean surface salinity with a spatial resolution of 93 miles (150 kilometers). The data will reveal how salinity changes over time and from one part of the ocean to another.

The Aquarius/SAC-D mission continues NASA and CONAE’s 17-year partnership. NASA provided launch vehicles and operations for three SAC satellite missions and science instruments for two.

JPL will manage Aquarius through its commissioning phase and archive mission data. Goddard will manage Aquarius mission operations and process science data. NASA’s Launch Services Program at the agency’s Kennedy Space Center in Florida is managing the launch.

CONAE is providing the SAC-D spacecraft, an optical camera, a thermal camera in collaboration with Canada, a microwave radiometer,; sensors from various Argentine institutions and the mission operations center there. France and Italy are contributing instruments.

See the Aquarius/SAC-D website for more information. , visit:

Posted on by Nancy Atkinson

Mississippi River Flooding As Seen from the Space Station

Flood water from the Mississippi river near New Madrid, Missouri, as seen by Paolo Nespoli on board the International Space Station. Credit:ESA/NASA

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Big Muddy, as the Mississippi River is known, looks especially big and muddy these days with record flooding occurring along the largest river in the US. The Mississippi has risen to levels not seen in since the 1920’s and 30’s, fed by heavy spring rains and the spring thaw from heavy snows in the northern US this winter. Here are some new images taken by International Space Station astronaut Paolo Nespoli, which show surprising detail of how the river has spread across farmland and through cities and towns. The image above shows the area around New Madrid, Missouri, along the border of Kentucky.

Flooding near Ridgely, Tennessee. Credit: ESA/NASA

In this image, levees are visible which are containing the flood near Ridgely, Tennessee.

Here, flooded areas from the Mississippi is about 5 miles wide. Credit: ESA/NASA
Flooding near Caruthersville, Missouri. Farmland, roads and bridges are under water. Credit: ESA/NASA

Last week, the US Army Corps of Engineers opened floodways in Missouri to keep pressure off levees protecting the town of Cairo, Illinois, flooding thousands of acres of farmland. This week, the Corp is preparing to flood up to three million acres in southern Louisiana in hopes of protecting large cities along the Mississippi River such as Baton Rouge and New Orleans, Louisiana. More than 25,000 people are preparing to leave the region before the spillways would be opened.

See more images from Nespoli on his Flickr page.

Posted on by Nancy Atkinson

Satellite Imagery Shows How Tornadoes Slashed Across Alabama, Mississippi

This image shows the path of exposed ground left in the wake of an EF5 tornado in Mississippi. Credit: MODIS Rapid Response Team at NASA GSFC.

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Some extraordinary satellite and radar imagery shows how the deadly tornado supercell slashed through Alabama and Mississippi last week, as in the image above, leaving a gash of exposed ground and destruction that is visible from space. The latest reports indicate fatalities from the outbreak now exceed 342 people, and according to the Washington Post, this is the most people killed by tornadoes in a two-day period since April 5-6, 1936 when 454 people died. The image was taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite on April 28. See more imagery below.

Part of the path of a 12-mile swath of destruction in Alabama from an EF4 tornado on April 27. Click to see the entire swath taken by a NOAA satellite. Credit: NOAA

The National Weather Service said an EF4, with winds around 175 miles per hour, created a 12-mile-long track of destruction. This tornado caused more than 20 deaths.

Radar sequence of tornado supercell thunderstorms that tracked from western Mississippi into southwest North Carolina. Credit: NCAR, Brian Tang.

This image is pretty amazing: it is a radar montage of the supercell showing some of the 150 tornadoes that were reported on April 27 and 28, 2011. This cell traveled about 450 miles and lasted over 8 hours.

This animation from the NASA Earth Observatory team starts on April 26 and runs through the morning of April 28. It shows a relatively stable mass of cold air—visible as a swirl of more-or-less continuous clouds—rotates in the north along the top of the image, and meanwhile, moist air pushes north and west from the Atlantic Ocean and Gulf of Mexico. The two air masses collide and generate severe weather, but the bad weather also was amplified by the jet stream on April 27, which helped generate the lines of intense thunderstorms and tornadoes.

Sources: NASA Earth Observatory, Washington Post, NOAA

Posted on by Nancy Atkinson

Satellite Captures 3-D View of Violent Storms that Ravaged the US on April 27-28

The Tropical Rainfall Measuring Mission satellite captured the rainfall rates occurring in the line of thunderstorms associated with a powerful cold front moving through the eastern U.S. on April 28, 2011. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour. The very small red areas are heavy rainfall at almost 2 inches (50 mm) per hour. Credit: NASA/SSAI, Hal Pierce

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NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite captured 3-D images of severe thunderstorms that were spawning tornadoes over the eastern United States on April 28, detecting massive thunderstorms and very heavy rainfall. Tornadoes associated with this extremely unstable weather left at least 202 dead across the Eastern U.S, with injuries numbering over a thousand.

The Tropical Rainfall Measuring Mission satellite captured the rainfall rates occurring in the line of thunderstorms associated with a powerful cold front moving through the eastern U.S. on April 28, 2011. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour. The very small red areas are heavy rainfall at almost 2 inches (50 mm) per hour. Credit: NASA/SSAI, Hal Pierce

TRMM flew over the strong cold front and captured data at 0652 UTC (2:52 AM EDT) on April 28, 2011. Most of the rainfall was occurring at moderate rates however, there were pockets of very heavy rainfall in Virginia, North Carolina, South Carolina, Georgia and Alabama where rain was falling at a rate of 2 inches (50 millimeters) per hour.

This TRMM radar vertical cross section shows that some of these violent storms reached to incredible heights of almost 17 km (~10.6 miles). Credit: NASA/SSAI, Hal Pierce

In the image above and the lead animation, TRMM data was used to generate a 3-D look at the storm. TRMM’s Precipitation Radar (PR) data was used by Hal Pierce of SSAI at NASA’s Goddard Space Flight Center in Greenbelt, Md. to create a 3-D structure of those storms. The image Pierce created is a TRMM radar vertical cross section that shows some of these violent storms reached to incredible heights of almost 17 km (~10.6 miles).

TRMM, is the Energizer Bunny of satellites as it keeps going and going. It was launched in 1997 and was scheduled at one time to be decommissioned in 2004. But its systems keep operating and it is has been able to keep gathering useful information on storms and climate. It now has operated well over a decade past its original life expectancy.

TRMM is managed by both NASA and the Japanese Space Agency.

Source: NASA