Posted on by VirtualAstro

Last & Best Chances to See NanoSail-D

Nanosail-D Pass Credit: Vesa Vauhkonen, Spaceweather.com

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Over the next few weeks, skywatchers will have excellent viewing opportunities for the NanoSail-D solar sail.

The satellite is coming to the end of its 95-day mission to test the viability of de-orbiting decommissioned satellites or space debris. NanoSail-D is now de-orbiting and slowly losing altitude in the Earths thin upper atmosphere.

As the satellite descends, viewing opportunities will improve.

To see NanoSail-D pass over, you will need to know exactly when it will be visible from your location. To do this, go to Heavens-above.com or Spaceweather.com where star charts with times and pass details will be displayed after you enter your observing site.

Once you know the time and location in the sky of the pass of the satellite, make sure you are able to get a good view of the part of the sky where the satellite due to appear. Give yourself plenty of time, go outside and get ready. I always set a 30 second reminder on my watch or cell phone, so I don’t have to fumble around or guess the time.

To enjoy the NanoSail-D passes:

• Make sure you know the right place in the sky and the time of the pass, by checking on the web.
• Make sure you will be able to get a clear view of it from your viewing location.
• Set an alarm or get ready for the pass as it only lasts a few seconds.
• NASA expects NanoSail-D to stay in orbit through May 2011.
• If you are an astrophotographer, don’t forget, NASA and SpaceWeather.com are having an imaging contest of NanoSail-D. Find out more here.
• Most of all, get your friends and family outside with you to watch NanoSail-D and enjoy!

Artist concept of Nanosail-D in Earth orbit. Credit: NASA
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

Posted on by Nancy Atkinson

Voyager Spacecraft Will Soon Enter Interstellar Space

After 33 years, NASA’s twin Voyager spacecraft are still actively working – gathering information, communicating with Earth, (and Tweeting!), and they are about to go where no space probe has gone before: into interstellar space. Because of the unfamiliar nature of the heliosphere, and especially its outermost layer, the heliosheath, it is not known exactly when the Voyagers will actually reach the “great beyond.”

“The heliosheath is 3 to 4 billion miles (4.8 to 6 billion km) in thickness,” said Voyager Project Scientist, Ed Stone. “That means we’ll be out within five years or so.” The V’ger’s Plutonium 238 heat source will keep the critical subsystems running through at least 2020, but after that, Stone says, “Voyager will become our silent ambassador to the stars.”

This video features highlights of the Voyager journeys to the outer planets and the discoveries they have made, and shows where they are now and where they are headed.

More info on the Voyagers, and here, too.

Posted on by Nancy Atkinson

MESSENGER Finds Where X Marks the Spot on Mercury

An unnamed crater on Mercury taken by MESSENGER's Narrow Angle Camera. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

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Buried treasure on Mercury? If so, I’d look here first. This image shows a currently unnamed crater with an “X” emblazoned on it. The perpendicular lines that cross the crater are secondary crater chains caused by ejecta from two primary impacts outside of the field of view, according to MESSENGER scientists. MESSENGER has been in orbit of Mercury since mid-March of this year, and its Mercury Dual Imaging System (MDIS) pivot and Narrow Angle Camera (NAC) spotted this unusual landform. MESSENGER will be mapping more than 90% of Mercury’s surface as part of a high-resolution surface morphology base map that will be created with MDIS.

See more about this image on the MESSENGER website.

Posted on by Nancy Atkinson

Early Stars Were Whirling Dervishes

Simulation of the formation of the first stars showing fast rotation. Credit: A. Stacy, University of Texas.

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Even though some of the first stars in the early universe were massive, they probably lived fast and furious lives, as they likely rotated much faster than their present-day counterparts. A new study on stellar evolution looked at a 12-billion-year-old star cluster and found high levels of metal in the stars – a chemical signature that suggests that the first stars were fast spinners.

“We think that the first generations of massive stars were very fast rotators – that’s why we called them spinstars,” said Cristina Chiappini of the Astrophysical Institute Potsdam in Germany, who led the team of astronomers.

These first generation stars died out long ago, and our telescopes can’t look back in time far enough to actually see them, but astronomers can get a glimpse of what they were like by looking at the chemical makeup of later stars. The first stars’ chemical imprints are like fossil records that can be found in the oldest stars we can study.

The general understanding of the early universe is that soon after the Big Bang, the Universe was made of essentially just hydrogen and helium. The chemical enrichment of the Universe with other elements had to wait around 300 million years until the fireworks started with the death of the first generations of massive stars, putting new chemical elements into the primordial gas, which later were incorporated in the next generations of stars.

Using data from ESO’s Very Large Telescope (VLT), the astronomers reanalyzed spectra of a group of very old stars in the Galactic Bulge. These stars are so old that only very massive, short-living stars with masses larger than around ten times the mass of our Sun should have had time to die and to pollute the gas from which these fossil records then formed. As expected, the chemical composition of the observed stars showed elements typical for enrichment by massive stars. However, the new analysis unexpectedly also revealed elements usually thought to be produced only by stars of smaller masses. Fast-rotating massive stars on the other hand would succeed in manufacturing these elements themselves.

“Alternative scenarios cannot yet be discarded – but – we show that if the first generations of massive stars were spinstars, this would offer a very elegant explanation to this puzzle!” said Chiappini.

A star that spins more rapidly can live longer and suffer different fates than slow-spinning ones. Fast rotation also affects other properties of a star, such as its colour, and its luminosity. Spinstars would therefore also have strongly influenced the properties and appearance of the first galaxies which were formed in the Universe. The existence of spinstars is now also supported by recent hydrodynamic simulations of the formation of the first stars of the universe by an independent research group.

Chiappini and her team are currently working on extending the stellar simulations in order to further test their findings. Their work is published in a Nature article on April 28, 2011.

Source: University of Potsdam, Nature

Posted on by Jason Major

Ride Along with Rhea

Animation made from raw Cassini image data acquired April 25, 2011

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Assembled from 29 raw images taken by the Cassini orbiter on Monday, April 25, this animation brings us along an orbital ride with Rhea as it crosses Saturn’s nighttime face, the planet’s shadow cast across the ringplane. Sister moons Dione and Tethys travel the opposite lane in the background, eventually appearing to sink into Saturn’s atmosphere.

Rhea's heavily cratered surface, imaged by Cassini on October 2010. NASA/JPL/SSI

The exposure varies slightly from frame to frame due to the fact that they are not all taken with the same color channel filter.

Rhea (1,528 kilometers, or 949 miles, wide), Dione (1,123 kilometers, or 698 miles wide) and Tethys (1,066 kilometers, or 662 miles wide) are all very similar in composition and appearance. The moons are composed mostly of water ice and rock, each covered in craters of all sizes and crisscrossed by gouges, scarps and chasms. All three are tidally locked with Saturn, showing the same face to their parent planet in the same way that the Moon does with Earth.

The Cassini spacecraft was 2,227,878 km (1,384,339 miles) from Rhea when the images were taken.

(The original images have not been validated or calibrated. Validated/calibrated images will be archived with the NASA Planetary Data System in 2012.)

Image credit: NASA / JPL / Space Science Institute. Animation by Jason Major.

Posted on by Ken Kremer

Brush Fires Erupt at Kennedy Space Center during Endeavour’s Last Countdown

Brush fires send billowing smoke skywards at the Kennedy Space Center on April 27, just 2 days before the last launch of Shuttle Endeavour. Credit: Ken Kremer

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KENNEDY SPACE CENTER – A large brush fire suddenly broke out this today (April 27) less than 1 mile fom the Kennedy Space Center (KSC) Press Site in the midst of the countdown to Space Shuttle Endeavour’s last launch, set for this Friday, April 29.

Huge plumes of billowing smoke were sent skyward over the spaceport starting around 1 p.m. from the fires and were spread out over more than 100 acres. The fires erupted at some distance behind the NASA Tweeters tent erected at the press site and were located just 3 miles from the shuttle launch pad. The cause of the fires is unknown but occurred after a long spell of dry weather at KSC.

Brush fire view from the countdown clock at press site at the Kennedy Space Center on April 27. Helicopters dumped water from buckets to bring the fire under control. Credit: Ken Kremer

Helicopters and NASA Firefighters were called in to put out the fires. Fire trucks careened past the countdown clock towards the nearby fire. The helicopters flew back and forth all afternoon dumping buckets of seawater onto the wildfires trying to bring it under control.

“The shuttle launch pad was never in any danger due to the Turn basin in between and it hasn’t impacted any launch operations,” KSC spokesman Allard Beutel told Universe Today.

The Universe Today team of Alan Walters and Ken Kremer witnessed the spectacular and potentially frightening scene first hand and onsite.

It looked like Armageddon all afternoon long and was finally contained tonight. Nothing like this ever occurred so close to a launch and its not clear if the fire would have caused a scrub on launch day. Check out our up close photo album.

NASA Fire truck at the Countdown clock during brushfires at KSC. Credit: Ken Kremer
NASA Fire brigade responds to KSC brush fire. Credit: Ken Kremer
Firefighters at KSC brush fire. Credit: Ken Kremer
A member of the KSC fire crew assesses the fire situation. Credit: Alan Walters.
A helicopter flies through the smoke and haze at KSC on April 27 during the brushfire. Credit: Alan Walters.
Photographers set up in attempt to photograph Endeavour on the launchpad, but smoke hinders their view. Credit: Alan Walters.
Fire at Kennedy Space Center, April 27, 2011. Credit: Alan Walters.
Posted on by Nancy Atkinson

Where In The Universe Challenge #146

Here’s this week’s image for the Where In The Universe Challenge, to test your visual knowledge of the cosmos. You know what to do: take a look at this image and see if you can determine where in the universe this image is from; give yourself extra points if you can name the spacecraft/telescope responsible for the image. We’ll provide the image today, but won’t reveal the answer until later. This gives you a chance to mull over the image and provide your answer/guess in the comment section. Please, no links or extensive explanations of what you think this is — give everyone the chance to guess.

UPDATE: The answer has now been posted below!

Ah, its springtime on Mars’ southern hemisphere! This is Mars, as seen by the HiRISE camera on the Mars Reconnaissance Orbiter. Specifically, this is a “spot” near the south pole of Mars (-84.3 degrees latitude and 242.1 degrees east longitude) called the Starfish region. MRO is monitoring how warmer weather is changing the polar landscape.

And here’s a look at a bigger view of the area.

For more info on this image see the HiRISE website!

Posted on by Nancy Atkinson

Sideways Looks at the Moon Like You’ve Never Seen it Before

An oblique look at the Moon from the Lunar Reconnaissance Orbiter. Credit: Moon Zoo, NASA/GSFC/Arizona State University

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The Zooites working at the Moon Zoo citizen science project have uncovered some very unique oblique views of the Moon taken by the Lunar Reconnaissance Orbiter. Occasionally, LRO takes “sideways glances” at the Moon instead of looking straight down like the spacecraft normally does. The Moon doesn’t really look like this close up, because these images aren’t scaled correctly (the width and height pixel scales are different by five times, the Zooites say in the Moon Zoo Forum), but they provide a distinctive look at the lunar surface, and things like craters on the side of a hill, — or perhaps an entrance to a cave — show up better than in normal images. Have fun looking at some more of these images below, or on the Moon Zoo Forum.

And don’t forget, if you aren’t working on at least one of the Zooniverse citizen science projects, you are missing out on mountains of fun!

Another oblique look at the Moon from the Lunar Reconnaissance Orbiter. Credit: Moon Zoo, NASA/GSFC/Arizona State University
LRO image M144564740RC. Credit: Moon Zoo, NASA/GSFC/Arizona State University.
LRO image M144653115RC. Credit: Moon Zoo, NASA/GSFC/Arizona State University.