Before there was Curiosity, before Spirit, and Opportunity, and even long before Sojourner, there was Lunokhod 1, the Soviet Union’s lunar rover that explored Mare Imbrium from November of 1970 to September the following year. It was a curious-looking machine, a steampunk fantasy reminiscent of something out of a Jules Verne novel. But until the Mars Exploration Rovers nearly 40 years later, Lunokhod 1 held the record for the longest-operating robotic rover on the surface of another world.
These images from the Lunar Reconnaissance Orbiter Camera (LROC) are the most detailed yet of the now-silent Soviet rover and its lander, Luna 17.
The lander, Luna 17, was launched from Earth orbit on November 10, 1970, and entered lunar orbit five days later. It successfully soft-landed in Mare Imbrium on November 17 and deployed the Lunokhod (“moon walker” in Russian) rover, which was powered by batteries that were recharged via solar power during the lunar day.
Luna 17 and Lunokhod 1's tracks. (NASA/GSFC/ASU)
The 5600 kg (12,345 lb.) Lunokhod 1 boasted a suite of scientific tools for exploring the lunar surface. It was equipped with a cone-shaped antenna, a highly directional helical antenna, four television cameras, and special extendable devices to impact the lunar soil for soil density and mechanical property tests.
An x-ray spectrometer, an x-ray telescope, cosmic-ray detectors, and a laser device were also included.
The super-steampunk Lunokhod 1 rover. (NASA/GSFC)
Operating for nearly 300 days — almost four times longer than planned — by the time it officially ceased operations in October 1971 Lunokhod 1 had traveled 10,540 meters and had transmitted more than 20,000 images, and had conducted over 500 lunar soil tests.
The images above were obtained during a low-altitude pass by LRO, which came within 33 km (20.5 miles) of the lunar surface.
This is a mosaic of the images covering the entire sky as observed by the Wide-field Infrared Survey Explorer (WISE), part of its All-Sky Data Release. Image Credit: NASA/JPL-Caltech/UCLA
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Love all the great things you can see in infrared? Then zoom on into the big view of the entire sky from the Wide-field Infrared Survey Explorer (WISE) mission. WISE has collected more than 15 trillion bytes of data with 2.7 million images of the sky at infrared light. It’s captured everything from nearby asteroids to distant galaxies, finding “Y-dwarfs,” a Trojan asteroid sharing Earth’s orbit, and stars and galaxies that had never been seen before, as well as showing astronomers that there are significantly fewer mid-size asteroids than previously thought.
Today NASA released a new atlas and catalog of the entire sky in infrared, and now even more discoveries are expected since anyone can have access to the whole sky as seen by the spacecraft.
“With the release of the all-sky catalog and atlas, WISE joins the pantheon of great sky surveys that have led to many remarkable discoveries about the universe,” said Roc Cutri, who leads the WISE data processing and archiving effort at the Infrared and Processing Analysis Center at the California Institute of Technology in Pasadena. “It will be exciting and rewarding to see the innovative ways the science and educational communities will use WISE in their studies now that they have the data at their fingertips.”
Thanks to John Williams at Starry Critters, you can now zoom into WISE’s entire map of the infrared sky. John notes some interesting things in the image: “The bright swath across the center is the Milky Way Galaxy; our home galaxy. The view is toward the center of the galaxy with the spiral arms stretching to the edges. Some artifacts were left in such as bright red spots off the plane of the galaxy. These are Saturn, Jupiter and Mars.”
The zodiacal light captures from Earth. Credit: ESO.
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Most of us have experienced the frustration of pollution, fog, or clouds turning a night of stargazing into an exercise in frustration. Turns out, NASA has been dealing with the same problems since it started launching large telescopes. Even in orbit, telescopes can’t see too well through the dust that litters the inner Solar System. But a team of NASA scientists have come up with a way to lift astronomy out of this cosmic fog.
Venus, Earth, and Mars all orbit within a dust cloud made by comets and occasional collisions between asteroids. This so-called zodiacal cloud is the Solar System’s most luminous feature after the Sun and can be up to a thousand times brighter than the objects astronomers are actually targeting. The light affects orbital observations the same way light from a full Moon affects ground based observations. The zodiacal cloud is so bright that it has interfered with every infrared, optical, and ultraviolet astronomical observation mission NASA has ever launched.
The components of the proposed EZE mission. Credit: NASA.
“To put it simply, it has never been night for space astronomers,” said Matthew Greenhouse, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, MD. Light from the cloud is greatest in the plane of Earth’s orbit, the same plane in which every space telescope operates.
So how is NASA planning to get away from the cloud? By tilting future telescopes’ orbits. This type of adjustment would let spacecraft spend a significant portion of each orbit above and below the thickest dust, giving it a clearer view of objects in space.
“Just by placing a space telescope on these inclined orbits, we can improve its sensitivity by a factor of two in the near-ultraviolet and by 13 times in the infrared,” Greenhouse explained. “That’s a breakthrough in science capability with absolutely no increase in the size of the telescope’s mirror.”
Greenhouse has teamed up with Scott Benson and the COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) study team, both at NASA’s Glenn Research Center in Cleveland, OH. They’re investigating missions to put a telescope in this type of angle plane — an extra-zodiacal orbit — using new developments in solar arrays, electric propulsion and lower-cost expendable launch vehicles.
They’ve developed a proof-of-concept mission called the Extra-Zodiacal Explorer (EZE), a 1,500-pound EX-class observatory. EZE would launch on a SpaceX Falcon 9 rocket. A powerful new solar-electric drive as its upper stage would direct the spacecraft on a gravity-assist manoeuver past Earth or Mars, a flyby that would redirect the mission into an orbit inclined by as much as 30 degrees to Earth’s.
A NEXT engine during a test fire. At the time the image was taken, in December 2009, the thruster had operated continuously for more than 25,000 hours; it has now run for more than 40,000 hours. Credit: NASA.
NASA’s Evolutionary Xenon Thruster (NEXT) engine is an improved type of ion drive. It operates by removing electrons from atoms of xenon gas and accelerating the charged ions through an electric field to create thrust. While these types of engine provide much less thrust at any given time than traditional chemical rockets, they are much more fuel efficient and can operate for years.
Two of these advanced engines, which get their power from onboard solar arrays, would be housed in the EZE upper stage. They would fire to send the spacecraft on the planetary flyby that would put it into an extra-zodiacal orbit. “We’ve run one NEXT thruster for over 40,000 hours in ground testing, more than twice the thruster operating lifetime needed to deliver the EZE spacecraft to its extra-zodiacal orbit,” Benson explained. “This is mature technology that will enable much more cost-effective space missions across both the astrophysics and planetary science disciplines.”
If this concept mission works, the team says, it will be the best performance from an observatory in the history of NASA’s Explorer program. It will also be a game changer. As Greenhouse explained, “it will make extra-zodiacal orbits available to any astronomer proposing to NASA’s Explorer program. This will enable unprecedented science capability for astrophysics Explorers.”
Over time, our Moon has changed from a glowing ball of magma, to being pummeled and pounded by impacts, to evolving to the current constant companion we see in the sky each night. With the Lunar Reconnaissance Orbiter, we’re getting a better understanding of just what has taken place on the Moon over its history. Thanks to the folks at Goddard’s Scientific Visualization Studio, this video provides a look at 4.5 billion years of the Moon in just two and a half minutes.
Microgravity — or “zero-g” as it’s sometimes called — is not a natural state for the human body to live in for prolonged periods of time. But that is what today’s astronauts are often expected to do, whether while on expedition aboard Space Station or during a future voyage to the Moon or Mars. A host of physical issues can result from the space environment, from bone loss and muscle atrophy to the risks associated from increased exposure to radiation.
Now, there’s another downside to long-term life in orbit: eye and brain damage.
A team of radiologists led by Dr. Larry A. Kramer from The University of Texas Medical School at Houston performed MRIs on 27 astronauts, measuring in each the shape and thickness of the rear of the eyes, optic nerve, optic nerve sheath and pituitary gland.
In 7 of the 27 astronauts flattening of the backs of the eyes was noted, and enlargement of the optic nerve was detected in nearly all of them — 26 out of 27.
In addition, four exhibited deformation of the pituitary gland.
The optic nerve. (NIH)
The changes to the eyes and optic nerves are similar to what are typically seen in those suffering from idiopathic intracranial hypertension (IIH), a disorder characterized by increased pressure within the skull. Symptoms typically include headache, dizziness and nausea, and if left untreated it can produce permanent vision loss through optic nerve damage.
“The MRI findings revealed various combinations of abnormalities following both short- and long-term cumulative exposure to microgravity also seen with idiopathic intracranial hypertension,” said Dr. Kramer. “Microgravity-induced intracranial hypertension represents a hypothetical risk factor and a potential limitation to long-duration space travel.”
Chief of flight medicine at NASA’s Johnson Space Center, Dr. William J. Tarver, noted that although no astronaut has been kept from flight duties as a result of such risks, NASA will continue to “closely monitor the situation” and has placed the potential danger “high on its list of human risks.”
The team’s paper was accepted into the journal Radiology on Feb. 1.
“Orbital and Intracranial Effects of Microgravity: Findings at 3-T MR Imaging.” Collaborating with Dr. Kramer were Ashot Sargsyan, M.D., Khader M. Hasan, Ph.D., James D. Polk, D.O., and Douglas R. Hamilton, M.D., Ph.D.
Update Oct. 24, 2013: Further investigation by researchers at Houston Methodist and Johnson Space Center have shown more evidence of long-term eye damage after just two weeks in orbit. Read more.
SOHO animation of the latest sun-diving comet (LASCO/NRL SOHO team)
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A new comet has been discovered by the SOHO team, and it — like Lovejoy before it, almost three months to the day — is headed directly toward the Sun. Discovered by SOHO’s SWAN instrument, the comet has been dubbed Comet SWAN… making this a real swan dive (or, perhaps more appropriately, its swan song.)
The animation above has a lot of random noise in it from recent solar outbursts… can you spot the comet? If not, read on…
Labeled frame of the LASCO image (courtesy of SpaceWeather.com)
There’s Comet SWAN, just above the darker silhouette of the bar that holds the shielding disk over the center of the imager (which blocks the glare from the Sun itself.)
The comet is likely another member of the Kreutz family of comets, an extended family of pieces that broke off a larger comet several hundred years ago (which itself may have been a survivor of a breakup in 371 B.C.!) Comet Lovejoy was also a Kretuz sungrazer but it was considerably larger and brighter, which may have helped it survive its Dec. 15 solar close encounter to re-emerge on the opposite side, surprising astronomers everywhere!
Images of the six galaxies with detected inflows taken with the Advanced Camera for Surveys on the Hubble Space Telescope. Most of these galaxies have a disk-like, spiral structure, similar to that of the Milky Way. Star formation activity occurring in small knots is evident in several of the galaxies' spiral arms. Because the spirals appear tilted in the images, Rubin et al. concluded that we are viewing them from the side, rather than face-on. This orientation meshes well with a scenario of 'galactic recycling' in which gas is blown out of a galaxy perpendicular to its disk, and then falls back in at different locations along the edge of the disk. Credit: K. Rubin, MPIA
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Got a teenager? Then you know the story. Go to look for your favorite bag of chips and they’re gone. You eat one portion of meat and they need three. If you like those cookies, then you better have a darn good place to stash them. And, while you’re at it, their car needs gas. Apparently there’s a reason for the word “universal”, because teenage galaxies aren’t much different. Thanks to some new studies done by ESO’s Very Large Telescope, astronomers have been able to take a much closer look at adolescent galaxies and their “feeding habits” during their evolution. Some 3 to 5 billion years after the Big Bang they were happiest when just provided with gas, but later on they developed a voracious appetite… for smaller galaxies!
Scientists have long been aware that early galaxy structures were much smaller than the grand spirals and hefty ellipticals which fill the present Universe. However, figuring out exactly how galaxies put on weight – and where the bulk supply comes from – has remained an enigma. Now an international group of astronomers have taken on more than a hundred hours of observations taken with the VLT to help determine how gas-rich galaxies developed.
“Two different ways of growing galaxies are competing: violent merging events when larger galaxies eat smaller ones, or a smoother and continuous flow of gas onto galaxies.” explains team leader, Thierry Contini (IRAP, Toulouse, France). “Both can lead to lots of new stars being created.”
The undertaking is is MASSIV – the Mass Assembly Survey with the VIsible imaging Multi-Object Spectrograph, a powerful camera and spectrograph on the VLT. It’s incredible equipment used to measure distance and properties of the surveyed galaxies Not only did the survey observe in the near infrared, but also employed a integral field spectrograph and adaptive optics to refine the images. This enables astronomers to map inner galaxy movements and content, as well as leaving room for some very surprising results.
“For me, the biggest surprise was the discovery of many galaxies with no rotation of their gas. Such galaxies are not observed in the nearby Universe. None of the current theories predict these objects,” says Benoît Epinat, another member of the team.
“We also didn’t expect that so many of the young galaxies in the survey would have heavier elements concentrated in their outer parts — this is the exact opposite of what we see in galaxies today,” adds Thierry Contini.
These results point towards a major change during the galactic “teenage years”. At some time during the young Universe state, smooth gas flow was a considerable building block – but mergers would later play a more important role.
“To understand how galaxies grew and evolved we need to look at them in the greatest possible detail. The SINFONI instrument on ESO’s VLT is one of the most powerful tools in the world to dissect young and distant galaxies. It plays the same role that a microscope does for a biologist,” adds Thierry Contini.
The team plans on continuing to study these galaxies with future instruments on the VLT as well as using ALMA to study the cold gas in these galaxies. However, their work with gas isn’t the only “station” on the block. In a separate study led by Kate Rubin (Max Planck Institute for Astronomy), the Keck I telescope on Mauna Kea, Hawaii, has been used to examine gas associated with a hundred galaxies at distances between 5 and 8 billion light-years – the older teens. They have found initial evidence of gas flowing back into distant galaxies that are actively forming new stars.
Images of the six galaxies with detected inflows taken with the Advanced Camera for Surveys on the Hubble Space Telescope. Most of these galaxies have a disk-like, spiral structure, similar to that of the Milky Way. Star formation activity occurring in small knots is evident in several of the galaxies' spiral arms. Because the spirals appear tilted in the images, Rubin et al. concluded that we are viewing them from the side, rather than face-on. This orientation meshes well with a scenario of 'galactic recycling' in which gas is blown out of a galaxy perpendicular to its disk, and then falls back in at different locations along the edge of the disk. Credit: K. Rubin, MPIA
Apparently, like a teenager with the munchies, matter finds its way into those galactic tummies. One feeding theory is an inflow from huge low-density gas reservoirs filling the intergalactic voids… another is huge cosmic matter cycle. While there is very little evidence to support either hypothesis, gases have been observed to flow away from some galaxies and may be moshed around by several different sources – such as supernovae events or peer pressure from gigantic stars.
“As this gas drifts away, it is pulled back by the galaxy’s gravity, and could re-enter the same galaxy in time scales of one to several billion years. This process might solve the mystery: the gas we find inside galaxies may only be about half of the raw material that ends up as fuel for star formation.” says Dr. Rubin. “Large amounts of gas are caught in transit, but will re-enter the galaxy in due time. Add up the galaxy’s gas and the gas currently undergoing cosmic recycling, and there is a sufficient amount of raw matter to account for the observed rates of star formation.”
It might very well be a case of cosmic recycling… but I’d feel safer hiding my cookies.
Comet Lovejoy re-emerging from behind the Sun on Dec. 15, 2011. (NASA/SDO)
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It was just about three months ago that the astronomy world watched in awe as the recently-discovered comet Lovejoy plummeted toward the Sun on what was expected to be its final voyage, only to reappear on the other side seemingly unscathed! Surviving its solar visit, Lovejoy headed back out into the solar system, displaying a brand-new tail for skywatchers in southern parts of the world (and for a few select viewers above the world as well.)
How did a loosely-packed ball of ice and rock manage to withstand such a close pass through the Sun’s blazing corona, when all expectations were that it would disintegrate and fizzle away? A few researchers from Germany have an idea.
Scientists from the Max Planck Institute for Extraterrestrial Physics and the Braunschweig University of Technology have hypothesized that Comet Lovejoy managed to hold itself together through the very process that, to most people, defines a comet: the outgassing of sublimated icy material.
As a comet near the Sun, the increased heating from solar radiation causes the frozen materials within the nucleus to sublimate — go directly and suddenly from solid to gas, skipping the liquid middle stage — and, in doing so, burst through the surface of the comet and create the long, hazy reflective tail that is so often associated with them.
Overview of the forces acting on sungrazing comets. (Illustration from paper.)
In the case of Lovejoy, which was on a direct path toward the Sun, the sublimation itself may have provided enough outward force across its surface to literally keep it together, according to the team’s research.
“The reaction force caused by the strong outgassing (sublimation) of the nucleus near the Sun acts to keep the nucleus together and to overcome the tidal disruption,” the paper claims.
In addition, the team states that the size of the comet’s nucleus can be derived using an equation that takes into consideration the combined forces of outgassing, the material composition of the comet’s nucleus, the comet’s own gravity and the tidal forces exerted by the comet’s close proximity to the Sun (i.e., the Roche limit).
Using that equation, the team concluded that the diameter of Comet Lovejoy’s nucleus is anywhere between 0.2 km and 11 km (.125 miles and 6.8 miles). Any smaller and it would have lost too much material during its pass (and had too little gravity); any larger and it would have been too thick for outgassing to provide enough counterbalancing force.
If this hypothesis is correct, taking a trip around the Sun may not mean the end for all comets… at least not those of a certain size!
Watch the video of Lovejoy’s Dec. 15 solar swing below:
The paper was submitted to the journal Icarus on March 8, 2012 by Bastian Gundlach. See the full text here.
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I just had to post this satellite photograph of Vancouver with the sediment plume streaming out of the Fraser River. Not just because it’s beautiful, which it is, but also because so much of my life is tied together with that city and river.
I was born in Vancouver, and spent half my time there and half my time over on Vancouver Island which is on the left-hand side of this image. I currently live on Vancouver Island, but I have to commute to Vancouver quite a bit, which involves taking a ferry ride across the Straight of Georgia. When you take the route that carries you from Nanaimo (on the island) over to Tsawassen (the ferry terminal that juts out), you have to cross this plume.
Where you see the plume depends on the tides and the amount of material flowing out of the Fraser River, but it’s a stunning sight to see. It’s like the water has been separated into two different colors, with a very distinct dividing line between them.
You can see the line from a few kilometers away standing on the ferry deck, and then it approaches and widens, and then you cross it. The water switches from deep blue to muddy brown with almost no blending in between. Even the shape of the waves in the plume is different.
A mosaic of 4 images taken of the Sun on Nov. 13, 2011. Credit: Leonard Mercer.
The rotation of the Sun is kind of hard to pin down. That’s because a day on the Sun depends on which part of the Sun you’re talking about. Confused yet? It kept astronomers puzzled for years too. Let’s look at how the rotation of the Sun changes.
A spot on the equator of the Sun takes 24.47 days to rotate around the Sun and return to the same position. Astronomers call this sidereal rotation period, which is different from the synodic period – the amount of time it takes for a spot on the Sun to rotate back to face the Earth. But the Sun’s rotation rate decreases as you approach the poles, so it can actually take 38 days for regions around the poles to rotate once.
The Sun’s rotation is seen by observing sunspots. All sunspots move across the face of the Sun. This motion is part of the general rotation of the Sun on its axis. Observations also indicate that the Sun does not rotate as a solid body, but it spins differentially. That means that it rotates faster at the equator of the Sun and slower at its poles. The gas giants Jupiter and Saturn also have differential rotation.
And so, astronomers have decided to measure the rotation rate of the Sun from an arbitrary position of 26° from the equator; approximately the point where we see most of the sunspots. At this point, it takes 25.38 days to rotate and return to the same spot in space.
Astronomers also know that the interior of the Sun rotated differently than the surface. The inner regions, the core and the radiative zone, rotate together like a solid body. And then the outer layers, the convective zone and photosphere, rotate at a different speed.
The Sun and the entire solar system orbits around the center of the Milky Way galaxy. The average velocity of the solar system is 828,000 km/hr. At that rate it will take about 230 million years to make one complete orbit around the galaxy. The Milky Way is a spiral galaxy. It is believed that it consists of a central bulge, 4 major arms, and several shorter arm segments. The Sun and the rest of our solar system is located near the Orion arm, between two major arms, Perseus and Sagittarius. The diameter of the Milky Way is about 100,000 light years and the Sun is located about 28,000 light-years from the Galactic Center. It has been suggested fairly recently that ours is actually a barred spiral galaxy. That means that instead of a bulge of gas and stars at the center, there is probably a bar of stars crossing the central bulge.
So when someone asks you what the rotation of the Sun is, ask them which part.
Here’s an article from Universe Today about the Sun’s magnetic field flip, and here’s an article about how there were no sunspots on the surface of the Sun.
