spaceplasma:

NASA’s Fermi, Swift See ‘Shockingly Bright’ Burst

A record-setting blast of gamma rays from a dying star in a distant galaxy has wowed astronomers around the world. The eruption, which is classified as a gamma-ray burst, or GRB, and designated GRB 130427A, produced the highest-energy light ever detected from such an event.

“We have waited a long time for a gamma-ray burst this shockingly, eye-wateringly bright,” said Julie McEnery, project scientist for the Fermi Gamma-ray Space Telescope at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The GRB lasted so long that a record number of telescopes on the ground were able to catch it while space-based observations were still ongoing.”

The burst subsequently was detected in optical, infrared and radio wavelengths by ground-based observatories, based on the rapid accurate position from Swift. Astronomers quickly learned that the GRB was located about 3.6 billion light-years away, which for these events is relatively close.

Gamma-ray bursts are the universe’s most luminous explosions. Astronomers think most occur when massive stars run out of nuclear fuel and collapse under their own weight. As the core collapses into a black hole, jets of material shoot outward at nearly the speed of light.

The jets bore all the way through the collapsing star and continue into space, where they interact with gas previously shed by the star and generate bright afterglows that fade with time.

If the GRB is near enough, astronomers usually discover a supernova at the site a week or so after the outburst.

“This GRB is in the closest 5 percent of bursts, so the big push now is to find an emerging supernova, which accompanies nearly all long GRBs at this distance,” said Goddard’s Neil Gehrels, principal investigator for Swift.

Ground-based observatories are monitoring the location of GRB 130427A and expect to find an underlying supernova by midmonth.

Explanation:

The 1st animation: The maps in the animation show how the sky looks at gamma-ray energies above 100 million electron volts (MeV) with a view centered on the north galactic pole. The first frame shows the sky during a three-hour interval prior to GRB 130427A. The second frame shows a three-hour interval starting 2.5 hours before the burst, and ending 30 minutes into the event. The Fermi team chose this interval to demonstrate how bright the burst was relative to the rest of the gamma-ray sky. This burst was bright enough that Fermi autonomously left its normal surveying mode to give the LAT instrument a better view, so the three-hour exposure following the burst does not cover the whole sky in the usual way.

The 2nd animation: This animation shows a more detailed Fermi LAT view of GRB 130427A. The sequence shows high-energy (100 Mev to 100 GeV) gamma rays from a 20-degree-wide region of the sky starting three minutes before the burst to 14 hours after. Following an initial one-second spike, the LAT emission remained relatively quiet for the next 15 seconds while Fermi’s GBM instrument showed bright, variable lower-energy emission. Then the burst re-brightened in the LAT over the next few minutes and remained bright for nearly half a day.

Credit: NASA/Swift/Stefan Immler

Billion-Pixel View of Mars Comes From Curiosity Rover

[Click image to enlarge - Image credit: NASA/JPL-Caltech/MSSS ]

This image is a scaled-down version of a full-circle view which combined nearly 900 images taken by NASA’s Curiosity Mars rover. The Full-Res TIFF and Full-Res JPEG provided in the top right legend are smaller resolution versions of the 1.3 billion pixel version for easier browser viewing and downloading. Viewers can explore the full-circle image with pan and zoom controls at http://mars.nasa.gov/bp1/.

The view is centered toward the south, with north at both ends. It shows Curiosity at the “Rocknest” site where the rover scooped up samples of windblown dust and sand. Curiosity used three cameras to take the component images on several different days between Oct. 5 and Nov. 16, 2012.

This first NASA-produced gigapixel image from the surface of Mars is a mosaic using 850 frames from the telephoto camera of Curiosity’s Mast Camera instrument, supplemented with 21 frames from the Mastcam’s wider-angle camera and 25 black-and-white frames — mostly of the rover itself — from the Navigation Camera. It was produced by theMultiple-Mission Image Processing Laboratory (MIPL) at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

This version of the panorama retains “raw” color, as seen by the camera on Mars under Mars lighting conditions. A white-balanced version is available at PIA16918. The view shows illumination effects from variations in the time of day for pieces of the mosaic. It also shows variations in the clarity of the atmosphere due to variable dustiness during the month while the images were acquired.

NASA’s Mars Science Laboratory project is using Curiosity and the rover’s 10 science instruments to investigate the environmental history within Gale Crater, a location where the project has found that conditions were long ago favorable for microbial life.

Malin Space Science Systems, San Diego, built and operates Curiosity’s Mastcam. JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory project for NASA’s Science Mission Directorate in Washington and built the Navigation Camera and the rover. Via JPL/NASA

• Read the news release here via JPL/NASA
• More information about the mission is online at: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/.
• You can follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity andhttp://www.twitter.com/marscuriosity.
• For more information about the Multi-Mission Image Processing Laboratory, see: http://www-mipl.jpl.nasa.gov/mipex.html.

Cassini Probe to Take Photo of Earth From Deep Space

[Image credit: NASA/JPL-Caltech]

“NASA’s Cassini spacecraft, now exploring Saturn, will take a picture of our home planet from a distance of hundreds of millions of miles on July 19. NASA is inviting the public to help acknowledge the historic interplanetary portrait as it is being taken. 

Earth will appear as a small, pale blue dot between the rings of Saturn in the image, which will be part of a mosaic, or multi-image portrait, of the Saturn system Cassini is composing. 

“While Earth will be only about a pixel in size from Cassini’s vantage point 898 million [1.44 billion kilometers] away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We hope you’ll join us in waving at Saturn from Earth, so we can commemorate this special opportunity.” 

Cassini will start obtaining the Earth part of the mosaic at 2:27 p.m. PDT (5:27 p.m. EDT or 21:27 UTC) and end about 15 minutes later, all while Saturn is eclipsing the sun from Cassini’s point of view. The spacecraft’s unique vantage point in Saturn’s shadow will provide a special scientific opportunity to look at the planet’s rings. At the time of the photo, North America and part of the Atlantic Ocean will be in sunlight. 

Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini’s highest-resolution camera. The probe’s position will allow it to turn its cameras in the direction of the sun, where Earth will be, without damaging the spacecraft’s sensitive detectors.”

Continue reading…

To learn more about the public outreach activities associated with the taking of the image, visit:http://saturn.jpl.nasa.gov/waveatsaturn . 

For more information about Cassini, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

spaceplasma:

Saturn’s magnetosphere changes with the seasons

This is an artist’s concept of the Saturnian plasma sheet based on data from Cassini magnetospheric imaging instrument. It shows Saturn’s embedded “ring current,” an invisible ring of energetic ions trapped in the planet’s magnetic field.

Saturn is at the center, with the red “donut” representing the distribution of dense neutral gas outside Saturn’s icy rings. Beyond this region, energetic ions populate the plasma sheet to the dayside magnetopause filling the faintly sketched magnetic flux tubes to higher latitudes and contributing to the ring current. The plasma sheet thins gradually toward the nightside. The view is from above Saturn’s equatorial plane, which is represented by grid lines. The moon Titan’s location is shown for scale. The location of the bow shock is marked, as is the flow of the deflected solar wind in the magnetosheath.

Researchers working with data from NASA’s Cassini spacecraft have discovered one way the bubble of charged particles around Saturn — known as the magnetosphere — changes with the planet’s seasons. The finding provides an important clue for solving a riddle about the planet’s naturally occurring radio signal. The results might also help scientists better understand variations in Earth’s magnetosphere and Van Allen radiation belts, which affect a variety of activities at Earth, ranging from space flight safety to satellite and cell phone communications.

The paper, just published in the Journal of Geophysical Research, is led by Tim Kennelly, an undergraduate physics and astronomy major at the University of Iowa, Iowa City, who is working with Cassini’s radio and plasma wave science team.

In data collected by Cassini from July 2004 to December 2011, Kennelly and his colleagues examined “flux tubes,” structures composed of hot, electrically charged gas called plasma, which funnel charged particles in towards Saturn. Focusing on the tubes when they initially formed and before they had a chance to dissipate under the influence of the magnetosphere, the scientists found that the occurrence of the tubes correlates with radio wave patterns in the northern and southern hemisphere depending upon the season. This seasonal effect is roughly similar to the way Earth’s northern lights appear more frequently in the spring and autumn months.

Radio emissions have been used to measure Jupiter’s rotation period reliably, and scientists thought it would also help them determine Saturn’s rotation period. To their chagrin, however, the pattern has varied over the visits by different spacecraft and even in radio emissions originating in the northern and southern hemispheres. The new results could help scientists hone in on why these signals vary the way they do.

For more on the finding, go to: http://now.uiowa.edu/2013/03/telling-time-saturn .

sagansense:

6 Weird Facts About Gravity

Here on Earth, we take gravity so for granted that it took an apple falling from a tree to trigger Isaac Newton’s theory of gravitation. But gravity, which draws objects together in proportion to their mass, is about much more than fallen fruit. Read on for some of the strangest facts about this universal force.

It’s all in your head
Gravity may be pretty consistent on Earth, but our perception of it isn’t. According to research published in April 2011 in the journal PLoS ONE, people are better at judging how objects fall when they’re sitting upright versus lying on their sides.

The finding means that our perception of gravity may be less based on visual cues of gravity’s real direction and more rooted in the orientation of the body. The findings may lead to new strategies to help astronauts deal with microgravity in space.

Coming down to Earth is tough
Speaking of astronauts, their experience has shown that a switch to weightlessness and back can be tough on the body. In the absence of gravity, muscles atrophy and bones likewise lose bone mass. According to NASA, astronauts can lose 1 percent of their bone mass per month in space.

When astronauts come back to Earth, their bodies and minds need time to recover. Blood pressure, which has equalized throughout the body in space, has to return to an Earthly pattern in which the heart must work hard to keep the brain nourished with blood. Occasionally, astronauts struggle with that adjustment. In 2006, astronautHeidemarie Stefanyshyn-Piper collapsed at a welcome-home ceremony the day after returning from a Space Shuttle mission to the International Space Station.

The mental readjustment can be just as tricky. In 1973, Skylab 2 astronaut Jack Lousma told Time magazine that he’d accidentally smashed a bottle of aftershave in his first days back from a month-long sojourn in space. He’d let go of the bottle in mid-air, forgetting that it would crash to the ground rather than just float there.

For weight loss, try Pluto
Pluto may no longer be a planet, but it’s still a good bet for lightening up. A 150-pound (68 kilogram) person would weigh no more than 10 pounds (4.5 kg) on the dwarf planet. The planet with the most crushing gravity, on the other hand, is Jupiter, where the same person would weigh more than 354 pounds (160.5 kg).

The planet humans are most likely to visit, Mars, would also leave explorers feeling light-footed. Mars’ gravitational pull is only 38 percent that of Earth’s, meaning a 150-pound person would feel like they weigh about 57 pounds (26 kg).

Gravity is lumpy
Even on Earth, gravity isn’t entirely even. Because the globe isn’t a perfect sphere, its mass is distributed unevenly. And uneven mass means slightly uneven gravity.

One mysterious gravitational anomaly is in the Hudson Bay of Canada (shown above). This area has lower gravity than other regions, and a 2007 study finds that now-melted glaciers are to blame.

The ice that once cloaked the area during the last ice age has long since melted, but the Earth hasn’t entirely snapped back from the burden. Since gravity over an area is proportional to the mass atop that region, and the glacier’s imprint pushed aside some of the Earth’s mass, gravity is a bit less strong in the ice sheet’s imprint. The slight deformation of the crust explains 25 percent to 45 percent of the unusually low gravity; the rest may be explained by a downward drag caused the motion of magma in Earth’s mantle (the layer just beneath the crust), researchers reported in the journal Science.

Without gravity, some bugs get tougher
Bad news for space cadets: Some bacteria become nastier in space. A 2007 study published in the journal Proceedings of the National Academy of Sciences found that salmonella, the bacteria that commonly causes food poisoning, becomes three times more virulent in microgravity. Something about the lack of gravity changed the activity of at least 167 salmonella genes and 73 of its proteins. Mice fed the gravity-free salmonella got sick faster after consuming less of the bacteria.

In other words, Michael Crichton’s “The Andromeda Strain” had it wrong: The danger of infection in space may not come from space bugs. It’s more likely our own bugs grown stronger would strike us.

Black holes at the center of galaxies
Named because nothing, not even light, can escape their gravitational clutches, black holes are some of the most destructive objects in the universe. At the center of our galaxy is a massive black hole with the mass of 3 million suns. Scarier thought? It might be “just resting,” according Kyoto University scientist Tatsuya Inui.

The black hole isn’t really a danger to us Earthlings — it’s both far away and it’s remarkably calm. But sometimes it does put on a show: Inui and colleagues reported in 2008 that the black hole sent out a flare of energy 300 years ago. Another study, released in 2007, found that several thousand years ago, a galactic hiccup sent a small amount of matter the size of Mercury falling into the black hole, leading to another outburst.

The black hole, named Sagittarius A*, is dim compared with other black holes.

“This faintness implies that stars and gas rarely get close enough to the black hole to be in any danger,” Frederick Baganoff, a researcher at the Massachusetts Institute of Technology who was involved with the 2007 study, told LiveScience’s sister site SPACE.com. “The huge appetite is there, but it’s not being satisfied.”

sagansense:

NASA Sees Giant Solar Wave Erupt from the Sun

The sun celebrated May Day with a spectacular solar eruption Wednesday, unleashing a colossal wave of super-hot plasma captured on camera by a NASA spacecraft.

The solar eruption occurred over a 2.5-hour period Wednesday (May 1) and appeared as a “gigantic rolling wave” on the sun in a video recorded by NASA’s Solar Dynamics Observatory, agency officials said in an image description. The solar eruption is what scientists call a coronal mass ejection (CME) — a type of sun storm that can fire off billions of tons of solar material at more than a million miles per hour, they added.

When aimed directly at Earth, the most powerful CME events can pose a risk to satellites and astronauts in orbit, as well as interfere with communications and navigation networks. They can even damage ground-based power infrastructure.

But the May Day solar eruption occurred on the side of the sun and was not aimed at Earth, NASA officials said. It produced a dazzlingly bright wave of plasma that expanded from the sun’s surface and then erupted from the sun’s side, or limb, into open space.

The sun is currently in an active phase of its 11-year solar weather cycle and is expected to reach its peak activity this year.

NASA’s Solar Dynamics Observatory is one of several sun-watching spacecraft that keeps constant watch on Earth’s nearest star to track solar weather patterns and storm events. The $850 million SDO mission launched in 2010 and records constant high-definition views of the sun in several different wavelengths, including the extreme ultraviolet range of the light spectrum used to make the video of the May 1 solar eruption.

electricspacekoolaid:

Murmurs of Earth - The Voyager Interstellar Record

Written by: Carl Sagan, Ann Druyan, Timothy Ferris, Jon Lomberg, Linda Salzman Sagan (Carl’s Ex Wife!) 

This is quite a gem I picked up at my local used book shop. I need to post better pictures, but this is just one of the gems I found there. I’ve been looking for this for quite awhile actually. This was straight off the shelves of 1978. It covers the whole process of getting the pictures, music, for the record and the stories from the people who worked on the project. One of whom is of course Carl Sagan. This is actually when Carl met Ann Druyan so it is interesting to see both her and Carl’s ex wife Linda on the same project. I will post more later on. 

8bitfuture:

NASA invites you to send a haiku to Mars.

NASA is inviting members of the public to submit their names and a personal message online for a DVD to be carried aboard a spacecraft that will study the Martian upper atmosphere.

The DVD will be in NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, which is scheduled for launch in November. The DVD is part of the mission’s Going to Mars Campaign coordinated at the University of Colorado at Boulder’s Laboratory for Atmospheric and Space Physics.

The DVD will carry every name submitted. The public also is encouraged to submit a message in the form of a three-line poem, or haiku. However, only three haikus will be selected. The deadline for all submissions is July 1. An online public vote to determine the top three messages to be placed on the DVD will begin July 15.

Submit your entry here.

(Source: 8bitfuture)

sagansense:

Chasing the Edge of the Solar System | Voyager 1 and 2

For most of it’s lifetime, Voyager 1 has been traveling through uncharted territory. Initially launched to study the outer planets, Voyager 1 has soldiered on past Jupiter and Saturn and on to the outer edges of the solar system. It’s currently the farthest human-made object from Earth, but when will it be the first spacecraft to travel between the stars? Well, we won’t know until we answer two more fundamental questions: Where does our solar system end and the rest of the space between the stars begin? And if you were at the “edge” of our solar system, how would you know you had left?

Recent scientific discussions on the Voyager spacecraft missions have captivated many people. And as the scientific debate swirled around the internet in near-real time, it became clear that these questions are not easy to answer.

As the Principal Investigator for NASA’s Interstellar Boundary Explorer, or IBEX, spacecraft, I lead a team that is also studying this last frontier of our solar system. Data from IBEX complements the Voyager spacecraft—both missions are working together to find the very farthest reaches of the solar system. Unlike the Voyager spacecraft, which are careening out into interstellar space, IBEX orbits the Earth, collecting particles that have traveled in from the solar system’s boundary region and beyond. From those particles, we can determine many things, including what the boundary is like and what, exactly, is happening out there.

More Than Planets
Most everyone knows our solar system is composed of small solid objects orbiting the Sun—planets, comets, and asteroids. But there’s more to it than that. Our Sun continuously emits a “wind” of material outward in all directions, typically at speeds of about a million miles per hour (1.6 million kilometers per hour). The solar wind is composed mostly of charged particles, such as electrons and protons. It also carries the Sun’s magnetic field.

As the solar wind streams away from the Sun, it races out past all the planets, past Pluto, and toward the space between the stars more than 10 billion miles away. We tend to think of that space as empty, but it’s not. Rather, it contains cold hydrogen gas, dust, ionized gas, and traces of other material. Called the interstellar medium, it’s a very thin mix that comes from exploded stars and the stellar wind of other stars.

When the magnetic fields of the solar wind hit the magnetic fields of the interstellar medium, they do not intermix. The expanding solar wind pushes against the interstellar medium, clearing out a cavity in interstellar space known as the heliosphere. The boundary of that bubble is where the solar wind’s strength exactly matches the pressure of the interstellar medium. We call it the heliopause, and it’s often considered to be the very outer edge of our solar system.

The Heliopause
A few things about the heliopause: It isn’t an impermeable wall. Instead, it’s more like the edge of a forest clearing—the boundary is well defined, but easily negotiated. It’s also shaped more like a drop of water than a uniform sphere. That’s because our entire heliosphere, which contains our Sun, the planets, and everything else in our solar system, is moving through the interstellar medium at about 50,000 miles per hour (80,000 kilometers per hour). That motion creates a wake in the interstellar medium, much like a boat moving through water. As the solar system travels through the interstellar medium the heliopause is closest at the “front,” or the foremost point in the direction in which our solar system is traveling. At that point, the heliopause is still over 10 billion miles, or 16 billion kilometers, from the Sun.

At least, that’s our best guess. We don’t know exactly where the boundary is or what it’s like. That’s what the IBEX and Voyager missions are trying to find out. IBEX lets us peer into the boundaries of our solar system to get a better idea of what it’s like and what’s happening there. However, because IBEX orbits the Earth, we cannot use it to mark where the boundary is located. That’s where Voyager 1 and 2 come in. Currently, they are directly sampling the boundary region. Several of the instruments on Voyager 1 and 2 are no longer working, including the cameras used to snap the stunning fly-by photos of Jupiter, Saturn, Uranus, and Neptune, but others that detect charged particles and magnetic fields are still gathering data.

Both Voyagers are traveling in roughly the same direction as our solar system through the interstellar medium. We expect Voyager 1, the quicker and farther out of the two, to reach the heliopause first. Currently, it’s just over 11 billion miles, or 18 billion kilometers, from the Sun. This is so distant that radio signals from Voyager 1, which are traveling at the speed of light, take 17 hours to reach Earth.

Three Criteria
Before we can declare that Voyager 1 has crossed the heliopause, we are waiting to observe three main changes:

A decrease in highly energetic charged particles from inside our heliosphere,

An increase in highly energetic charged particles from outside our heliosphere,

And a change in the strength and direction of the magnetic field, matching that outside the heliosphere.

Voyager 1 observed the first two in late 2012, and IBEX has provided what are likely the best observations of the third. By using IBEX to look at particles that have traveled in from outside the heliosphere, we have an idea of the direction of the magnetic field beyond the solar system, and it’s very different from the Sun’s, which is carried out by the solar wind. So far Voyager 1 hasn’t observed this change direction of the magnetic field. That’s why we don’t think that Voyager 1 has crossed the heliopause—yet.

Now, Voyager 1 has clearly passed into a new region of space, one that we have not detected before. Every new bit of data coming from the venerable spacecraft is teaching us more about this uncharted territory. All of this information is new, and we are learning more every day.

So, do we know when Voyager 1 will cross the heliopause? We really have no idea. And that’s part of the fun. But learning about the edge of space is more than just an esoteric pursuit. Our heliosphere is a protective cocoon, a crucial layer of shielding against dangerous charged particles, known as galactic cosmic rays, that are harmful to living things. Understanding it will help us understand how the heliosphere has protected our solar system, enabling life to flourish on this planet we call home. And someday, that knowledge will help us prepare for our first voyage beyond the protective cocoon of the solar system, when we step across the threshold and venture into deep space.

image 1: The identical Voyager 1 and Voyager 2 are currently probing the farthest reaches of the solar system.

image 2: As solar wind pushes out against the interestellar medium, it creates a bubble known as the heliosphere; the boundary between the two is known as the heliopause. The termination shock is where the solar wind slows as it presses against more of the interstellar medium, which also raises the plasma’s temperature. The bow wave is where the interstellar medium material piles up in front of our heliosphere, similar to water in front of a moving boat.

image 3: The IBEX satellite orbits the Earth, capturing particles that have traveled into the solar system from beyond the heliosphere.

via NOVANext, PBS.org

Stay Curious! Watch: And Still They Move: Ann Druyan on Carl, Love, and Voyager

Adopt-an-Alien-Planet Campaign Launches Today (May 1st)

A new campaign aims to start giving popular names to the hundreds of alien planets that have been discovered around the Milky Way galaxy.

The space-funding company Uwingu announced this “Adopt-a-Planet” effort today (May 1), asking the public to propose and vote on names for the many and varied worlds now known beyond our solar system.

Any moniker that receives at least 1,000 votes earns its nominator the chance to “adopt” (and name) theexoplanet of his or her choice. Such winners will also receive an adoption certificate, links to detailed information about the adopted planet and $100 in Uwingu store credits, company officials said. [The Strangest Alien Planets (Gallery)]

Adopt-a-Planet is similar to a month-long contest Uwingu staged recently to give a people’s-choice name to Alpha Centauri Bb, the closest known exoplanet to Earth at just 4.3 light-years away. (The winner: Albertus Alauda.)

The new adoption effort, however, is open-ended and seeks names for many different alien worlds.

“We’re happy to have winner after winner after winner,” Uwingu CEO Alan Stern, a former NASA science chief who also heads the agency’s New Horizons mission to Pluto, told SPACE.com. “There are plenty of exoplanets out there.”

(Source: electricspacekoolaid)

The Ultimate Photo Shoot Location: Targeting Earth Photographs From Orbit Inside the Cupola, NASA astronaut Chris Cassidy, an Expedition 36 flight engineer, uses a 400mm lens on a digital still camera to photograph a target of opportunity on Earth some 250 miles below him and the International Space Station. Cassidy has been aboard the orbital outpost since late March and will continue his stay into September.

[Image Credit: NASA via nasagoddard]

This Week in Science - June 3 - 9, 2013:

• Molecule appearances here.
• Widest tornado recorded here.
• Hula painted frog here.
• Polymer opal here.
• Neanderthal tumor here.
• Oldest fossil primate skeleton here.
• Thought powered helicopter here.
• Lithium-sulfur battery here.
• Genital “loss” in birds here.
• NASA intergalactic GPS here.
• Bio-engineered blood vessel here.
• Teleporting information here.

(Source: thescienceofreality)

spaceplasma:

Coronal Helix

An unusual helix-shaped coronal mass ejection was observed by a NASA spacecraft in June 1998. The main body of the sun—outlined in white—is blocked by a coronagraph.

Coronal mass ejections, or CMEs, are mammoth clouds of charged particles that get hurled through the sun’s atmosphere at millions of miles an hour. A CME contains billions of tons of charged particles and can expand until it’s larger than the sun itself.

Credit: LASCO

spaceplasma:

Scientists Bounce Laser Beams Off Old Soviet Moon Rover

Scientists have successfully bounced a laser off the Soviet Union’s old Lunokhod 1 rover, which trekked across the moon’s landscape more than four decades ago.

Lunokhod 1 was the first remote-controlled rover ever to land on another celestial body. The wheeled vehicle was carried to the lunar surface by a spacecraft called Luna 17, touching down in the Sea of Rains on Nov. 17, 1970.

Among its instruments, the rover toted a French-built laser retroreflector consisting of 14 corner cubes that can reflect laser light beamed from Earth. 

Attempts to contact the rover after the lunar night that began on Sept. 14, 1971, were unsuccessful, apparently due to a component failure on the rover. Lunokhod 1’s days of rambling around the moon formally ended on Oct. 4, 1971, after 11 lunar day-night cycles (322 Earth days).

The historical difficulty of ranging on Lunokhod 1 may have been due to a number of factors. The reflector may have been dusty, or its cover could have closed. Or the rover may not have been parked in view of Earth.

In the end, however, “it was more a problem of lack of confidence than to a technical difficulty,” Torre said.

Poor weather conditions prevented the scientists from getting a good determination of the Lunokhod 1 reflector’s efficiency. Still, the results have buoyed the interest of Earth-based scientists to continue beaming their lasers at the long-dead rover.

A retroreflector array was also left on the moon by the landing crew of NASA’s Apollo 11 mission in 1969, while two more retroreflector arrays were set up by Apollo 14 and Apollo 15 moonwalkers.

The final end-of-mission location of Lunokhod 1 was uncertain until 2010. But thanks to images snapped by NASA’s Lunar Reconnaissance Orbiter (LRO), both the Luna 17 lander and Lunokhod 1 were spotted.

Lunokhod 1 came to its final stop on a site situated around 1.4 miles (2.3 kilometers) north of its point of landing.

The success last month by the Grasse station was not the first laser ranging effort targeting the “lost” Lunokhod 1 reflector.

In April 2010, specialists at the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) in southern New Mexico used the LRO images to first pinpoint the locale of Lunokhod 1, closely enough for laser range measurements.

Surprisingly, the APOLLO researchers reported that the craft’s retroreflector was returning much more light than other reflectors on the moon.

Lunar laser ranging has been made possible by combining advances in laser technology, data processing and precision timing via atomic clocks, according to the International Laser Ranging Service, a service of the International Association of Geodesy.

Lunar laser ranging uses short-pulse lasers and state-of-the-art optical receivers and timing electronics to measure how long it takes light beamed from ground stations to travel to retroreflector arrays on the moon and back again.

It takes just two and a half seconds for light to make this roundtrip trek, requiring use of an atomic clock.

Because the reflectors on the moon are relatively small and a laser beam naturally loses its intensity with distance, only a tiny fraction of the signal makes it back. However, the information is sufficient for precise calculation of the Earth and moon’s movement: speed of rotation, axial variation and orbital deviation (taking into account, of course, the influence of other celestial bodies such as the sun).

Credit: SPACE.com

spaceplasma:

Coronal Helix

An unusual helix-shaped coronal mass ejection was observed by a NASA spacecraft in June 1998. The main body of the sun—outlined in white—is blocked by a coronagraph.

Coronal mass ejections, or CMEs, are mammoth clouds of charged particles that get hurled through the sun’s atmosphere at millions of miles an hour. A CME contains billions of tons of charged particles and can expand until it’s larger than the sun itself.

Credit: LASCO