Click on the image to download the full map and explore it in more detail.
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Was the early solar system bombarded with lots of big impacts? This is a question that has puzzled scientists for over 35 years. And it’s not just an academic one. We know from rocks on Earth that life began to evolve very early on, at least 3.8 billion years ago. If the Earth was being pummeled by large impacts at this time, this would certainly have affected the evolution of life. So, did the solar system go through what is known as the Late Heavy Bombardment (LHB)? Exciting new research, using data from the Lunar Reconnaissance Orbiter Camera (LROC) may cast some doubt on the popular LHB theory.
It’s actually quite a heated debate, one that has polarized the science community for quite some time. In one camp are those that believe the solar system experienced a cataclysm of large impacts about 3.8 billion years ago. In the other camp are those that think such impacts were spread more evenly over the time of the early solar system from approximately 4.3 to 3.8 billion years ago.
The controversy revolves around two large impact basins, which are found fairly close to each other on the Moon. The Imbrium basin is one of the youngest basins on the near side of the Moon, while the Serenetatis basin is thought to be one of the oldest. Both are flooded with volcanic basalts and are big enough to be seen from Earth with the naked eye.
What if the Apollo 17 samples didn't come from the Serenitatis basin, where the astronauts collected them, but rather from the Imbrium basin, located some 600 km away? Studies from the new Lunar Reconnaissance Orbiter Camera suggest this may be the case. If true, this means Serenitatis is much older than the Imbrium basin and a solar system-wide impact catastrophe is not needed to explain the uncannily close ages of the Imbrium and Serenitatis basins.
Image credit: NASA
Click on the image to download the full map and explore it in more detail.
Scientists know the relative ages of such lunar basins because of a concept called superposition. Basically, superposition states that what is on top must be younger than what is beneath. Using such relationships, scientists can determine which basins are older and which are younger.
To get an absolute age, though, scientists need actual bits of rock, so they can use radiometric dating techniques. The lunar samples returned by the Apollo program provided exactly that. But, the Apollo samples suggest that the Imbrium and Serenitatis basins are barely 50 million years apart.
Relative age dating tells us there are over 30 other basins that formed within that time frame. This means that roughly one major impact occurred every 1.5 million years! Now, 1.5 million years may sound like a long time. But consider the last large impact that happened on Earth, the Chicxulub event 65 million years ago, which is thought to have exterminated the dinosaurs. Imagine another 40 dinosaur-killing impacts occurring since then. It would be surprising if any life survived such a barrage!
This is why a team of researchers, led by Dr. Paul Spudis of the Lunar and Planetary Institute, is looking very carefully at this question. Their research is using the principle of superposition to show that several of the areas visited by the Apollo program were blanketed by material from the Imbrium impact. This could mean that many of the collected Apollo materials may be sampling the same event.
Dr. Spudis’s research focuses on the Montes Taurus area, between the Serenitatis and Crisium basins, not far from the Apollo 17 landing site. This is a region dominated by sculpted hills that have been interpreted to be ejected material from the adjacent Serenitatis basin impact. But, Dr. Spudis and his team have found that, instead, this sculpted material comes from the Imbrium basin some 600 kilometers away.
Previous data of this area, from the Lunar Orbiter IV camera, hadn’t shown this because a fog on the camera lens made the details difficult to see (this fog problem was eventually resolved, and Lunar Orbiter IV provided a lot of useful data on other parts of the Moon).The new LROC data, however, shows that the sculpted terrain seen at Apollo 17 is very widespread, extending far beyond the Montes Taurus region. Furthermore, the grooves and lineated features of this terrain point to the Imbrium basin, not the Serenitatis basin, and line up with similar features in the Alpes and Fra Mauro Formations, which are known to be ejecta from the Imbrium impact. In the north of Serenitatis, these Imbrium formations even seem to transform into the Montes Taurus, confirming that the sculpted hills do, in fact, originate from the Imbrium impact.
Recent high quality data from the Lunar Reconnaissance Orbiter Camera shows that the sculpted terrain, which is present at the Apollo 17 landing site, is related to material that is known to be from the Imbruim impact. This means that Apollo 17 may have sampled Imbrium and not Serenitatis material. This could explain the unusually close ages of these two basins, suggested by the Apollo samples. If so, the Serenitatis impact may have occurred much earlier than previously thought, meaning that a barrage of frequent bombardments did not occur, and life on Earth could have evolved without being molested by too many impact events.
Image credit: NASA/GSFC/Arizona State University
Click on the image to explore the LROC data in greater detail.
If the sculpted hills are Imbruim ejecta, then it is possible that Apollo 17 sampled Imbrium and not Serenitatis materials. That casts suspicion on the very close radiometric ages of these two basins. Perhaps these ages are so close because we effectively measured the same material. In that case, the age of Serenitatis could be much older than the 3.87 billion years the Apollo 17 samples suggest. If true, this would mean that there was no Late Heavy Bombardment at the time life was forming on the early Earth, leaving life to evolve with relatively few impact-related interruptions.
Titan and Dione seen on December 10, 2011 by the Cassini spacecraft. (NASA/JPL/SSI/J. Major)
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It’s been said many times that the most Earthlike world in our solar system is not a planet at all, but rather Saturn’s moon Titan. At first it may not seem obvious why; being only a bit larger than the planet Mercury and coated in a thick opaque atmosphere containing methane and hydrocarbons, Titan sure doesn’t look like our home planet. But once it’s realized that this is the only moon known to even have a substantial atmosphere, and that atmosphere creates a hydrologic cycle on its surface that mimics Earth’s – complete with weather, rain, and gully-carving streams that feed liquid methane into enormous lakes – the similarities become more evident. Which, of course, is precisely why Titan continues to hold such fascination for scientists.
Now, researchers have identified yet another similarity between Saturn’s hazy moon and our own planet: Titan’s energy budget is in equilibrium, making it much more like Earth than the gas giant it orbits.
A team of researchers led by Liming Li of the Department of Earth and Atmospheric Sciences at the University of Houston in Texas has completed the first-ever investigation of the energy balance of Titan, using data acquired by telescopes and the Cassini spacecraft from 2004 to 2010.
Energy balance (or “budget”) refers to the radiation a planet or moon receives from the Sun versus what it puts out. Saturn, Jupiter and Neptune emit more energy than they receive, which indicates an internal energy source. Earth radiates about the same amount as it receives, so it is said to be in equilibrium… similar to what is now shown to be the case for Titan.
Blue hazes hover high above thicker orange clouds over Titan's south pole (NASA/JPL/SSI)
The energy absorption and reflection rates of a planet’s – or moon’s! – atmosphere are important clues to the state of its climate and weather. Different balances of energy or changes in those balances can indicate climate change – global cooling or global warming, for instance.
Of course, this doesn’t mean Titan is a balmy world. At nearly 300 degrees below zero (F) it has an environment that even the most extreme Earth-based life would find inhospitable. Although Titan’s atmosphere is ten times thicker than Earth’s its composition is very different, permitting easy passage of infrared radiation (a.k.a. “heat”) and thus exhibits an “anti-greenhouse” effect, unlike Earth or, on the opposite end of the scale, Venus.
Still, some stable process is in place on Saturn’s moon that allows for distribution of solar energy across its surface, within its atmosphere and back out into space. With results due in from Cassini from a flyby on Jan. 2, perhaps there will soon be even more clues as to what that may be.
The team’s report was published in the AGU’s Geophysical Research Letters on December 15, 2011. Li, L., et al. (2011), The global energy balance of Titan, Geophys. Res. Lett., 38, L23201, doi:10.1029/2011GL050053.
Take a good close look at the Moon today and consider this; Two new Moon’s just reached orbit.
NASA is ringing in the New Year with a double dose of champagne toasts celebrating the back to back triumphal insertions of a pair of tiny probes into tandem lunar orbits this weekend that seek to unravel the hidden mysteries lurking deep inside the Moon and figure out how the inner solar system formed eons ago.
Following closely on the heels of her twin sister, NASA’s GRAIL-B spacecraft ignited her main braking rockets precisely as planned on New Year’s Day (Jan.1) to go into a formation flying orbit around the Moon, chasing behind GRAIL-A which arrived on New Year’s Eve (Dec. 31).
“Now we have them both in orbit. What a great feeling!!!!” NASA manager Jim Green told Universe Today just minutes after the thruster firing was done. Green is NASA’s Director of Planetary Science and witnessed the events inside Mission Control at the Jet Propulsion Laboratory (JPL) in Pasadena, Ca.
“It’s the best New Year’s ever!!” Green gushed with glee.
GRAIL-B spacecraft entered Lunar Orbit on New Year’s Day 2012. Artist concept of GRAIL-B performing its lunar orbit insertion burn. Credit: NASA/JPL-Caltech
The new lunar arrivals of GRAIL-A and GRAIL-B capped a perfect year for NASA’s Planetary Science research in 2011.
“2011 began the Year of the Solar System – which is a Mars year (~670 Earth days long)… and includes Grail B insertion, Dawn leaving Vesta this summer … And the landing of MSL! ,” Green said.
NASA’s GRAIL-A & GRAIL-B are orbiting the Moon in this image taken on Jan. 2, 2012 after Lunar Orbit Insertions on New Year’s Weekend. Click to enlarge.
Credit: Ken Kremer
“Cheers in JPL mission control as everything is looking good for GRAIL-B. It’s going to be a great 2012!!” JPL tweeted shortly after confirming the burn successfully placed GRAIL-B into the desired elliptical orbit.
After years of hard work, GRAIL principal investigator Maria Zuber of MIT told Universe Today that she was very “relieved”, soon after hearing the good news at JPL Mission Control.
“Since GRAIL was originally selected I’ve believed this day would come,” Zuber told me shortly after the GRAIL-B engine firing was declared a success on New Year’s Day.
“But it’s difficult to convey just how relieved I am right now. Time for the Science Team to start their engines !”
Artist's concept depicts how the science instrument on the mirror image twin GRAIL spacecraft will send signals to each other to map the Moon's gravity and then transmit the data to Earth. Credit: NASA
At 2:43 p.m. PST (5:43 p.m. EST) on New Year’s Day, the main thruster aboard GRAIL-B automatically commenced firing to slow down the spacecraft’s approach speed by about 430 MPH (691 kph) and allow it to be captured into orbit by the Moon’s gravity. The preprogrammed maneuver lasted about 39 minutes and was nearly identical to the GRAIL-A firing 25 hours earlier.
The hydrazine fueled main thrusters placed the dynamic spacecraft duo into near-polar, highly elliptical orbits.
Over the next two months, engineers will trim the orbits of both spacecraft to a near-polar, near-circular formation flying orientation. Their altitudes will be lowered to about 34 miles (55 kilometers) and the orbital periods trimmed from their initial 11.5 hour duration to about two hours.
The science phase begins in March 2012. For 82 days, the mirror image GRAIL-A and GRAIL-B probes will be flying in tandem with an average separation of about 200 kilometers as the Moon rotates beneath.
“GRAIL is a Journey to the Center of the Moon,” Zuber explained at a media briefing. “It will use exceedingly precise measurements of gravity to reveal what the inside of the Moon is like.”
As one satellite follows the other, in the same orbit, they will perform high precision range-rate measurements to precisely measure the changing distance between each other to within 1 micron, the width of a red blood cell, using a Ka-band instrument.
When the first satellite goes over a higher mass concentration, or higher gravity, it will speed up slightly. And that will increase the distance. Then as the second satellite goes over, that distance will close again.
The data returned will be translated into gravitational field maps of the Moon that will help unravel information about the makeup of the Moon’s mysterious core and interior composition. GRAIL will gather three complete gravity maps over the three month mission.
“There have been many missions that have gone to the Moon, orbited the Moon, landed on the Moon, brought back samples of the Moon,” said Zuber. “But the missing piece of the puzzle in trying to understand the Moon is what the deep interior is like.”
“Is there a core? How did the core form? How did the interior convect? What are the impact basins on the near-side flooded with magma and give us this Man-in-the-Moon shape whereas the back side of the Moon doesn’t have any of this? These are all mysteries that despite the fact we’ve studied the Moon before, we don’t understand how that has happened. GRAIL is a mission that is going to tell us that.”
“We think the answer is locked in the interior,” Zuber elaborated.
How will the twins be oriented in orbit to gather the data ?
“The probes will be pointed at one another to make the highly precise measurements,” said GRAIL co-investigator Sami Asmar of JPL to Universe Today. “The concept has heritage from the US/German GRACE earth orbiting satellites which mapped Earth’s gravity field. GRACE required the use of GPS satellites for exactly knowing the position, but there is no GPS at the Moon. So GRAIL was altered to compensate for no GPS at the Moon.”
GRAIL will map the gravity field by 100 to 1000 times better than ever before.
“We will learn more about the interior of the Moon with GRAIL than all previous lunar missions combined,” says Ed Weiler, the recently retired NASA Associate Administrator of the Science Mission Directorate in Washington, DC.
The GRAIL twins blasted off from Florida mounted side by side atop a Delta II booster on September 10, 2011 and took a circuitous 3.5 month low energy path to the Moon to minimize the overall costs.
So when you next look at the sky tonight and in the coming weeks just imagine those mirror image GRAIL twins circling about seeeking to determine how we all came to be !
GRAIL Project manager David Lehman cuts the cake for team members at JPL to celebrate 2 for 2 at the Moon. Credit: NASA/Jim GreenGRAIL team at JPL toasts success as twin spacecraft both went into orbit around the Moon on New Year’s weekend.
GRAIL-A and GRAIL-B flying in tandem using a precision formation-flying technique. Credit: NASA
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Cheers erupted after the first of NASA’s twin $496 Million Moon Mapping probes entered orbit on New Year’s Eve (Dec. 31) upon completion of the 40 minute main engine burn essential for insertion into lunar orbit. The small GRAIL spacecraft will map the lunar interior with unprecedented precision to deduce the Moon’s hidden interior composition.
“Engines stopped. It’s in a great initial orbit!!!! ”
NASA’s Jim Green told Universe Today, just moments after verification of a successful engine burn and injection of the GRAIL-A spacecraft into an initial eliptical orbit. Green is the Director of Planetary Science at NASA HQ and was stationed inside Mission Control at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Ca (see photos below).
“Pop the bubbly & toast the moon! NASA’s GRAIL-A spacecraft is in lunar orbit,” NASA tweeted shortly after verifying the critical firing was done. “Burn complete! GRAIL-A is now orbiting the moon and awaiting the arrival of its twin GRAIL-B on New Year’s Day.”
The firing of the hydrazine fueled thruster was concluded at 5 PM EST (2 PM PST) today, Dec. 31, 2011 and was the capstone to a stupendous year for science at NASA.
“2011 was definitely the best year ever for NASA Planetary Science,” Green told me today. “2011 was the “Year of the Solar System”.
“GRAIL-A is in a highly elliptical polar orbit that takes about 11.5 hours to complete.”
“We see about the first eight to ten minutes of the start of the burn as it heads towards the Moon’s southern hemisphere, continues as GRAIL goes behind the moon and the burn ends about eight minutes or so after it exits and reappears over the north polar region.”
“So we watch the beginning of the burn and the end of the burn via the Deep Space Network (DSN). The same thing will be repeated about 25 hours later with GRAIL-B on New Year’s Day [Jan 1, 2012],” Green explained.
The orbit is approximately 56-miles (90-kilometers) by 5,197-miles (8,363-kilometers around the moon. The probe barreled towards the moon at 4400 MPH and skimmed to within about 68 miles over the South Pole.
“My resolution for the new year is to unlock lunar mysteries and understand how the moon, Earth and other rocky planets evolved,” said Maria Zuber, GRAIL principal investigator at the Massachusetts Institute of Technology in Cambridge. “Now, with GRAIL-A successfully placed in orbit around the moon, we are one step closer to achieving that goal.”
Zuber witnessed the events in Mission Control along with JPL Director Charles Elachi (see photos).
GRAIL team at JPL Mission Control celebrates successful insertion of GRAIL-A into Lunar Orbit of New Year’s Eve. From Left: David Lehman, GRAIL Project Manager of JPL, Prof Maria Zuber, GRAIL Principal Investigator of MIT, Charles Elachi, JPL Director. Credit: NASA/Jim Green
The mirror twin, known as GRAIL-B, was less than 30,000 miles (48,000 km) from the moon as GRAIL A achieved orbit and closing at a rate of 896 mph (1,442 kph). GRAIL-B’s insertion burn is slated to begin on New Year’s Day at 2:05 p.m. PST (5:05 p.m. EST) and will last about 39 minutes.
GRAIL-B is about 25 hours behind GRAIL-A, allowing the teams enough time to rest and prepare, said David Lehman, GRAIL project manager at JPL.
“With GRAIL-A in lunar orbit we are halfway home,” said Lehman. “Tomorrow may be New Year’s everywhere else, but it’s another work day around the moon and here at JPL for the GRAIL team.”
GRAIL-A spacecraft achieved Lunar Orbit Insertion on New Year’s Eve. Artists concept shows twin GRAIL spacecraft orbiting the Moon. GRAIL-A and GRAIL-B flying in tandem using a precision formation-flying technique. Credit: Lockheed Martin
Engineers will then gradually lower the tandem flying satellites into a near-polar near-circular orbital altitude of about 34 miles (55 kilometers) with an average separation of about 200 km. The 82 day science phase will begin in March 2012.
“GRAIL will globally map the moon’s gravity field to high precision to deduce information about the interior structure, density and composition of the lunar interior. We’ll evaluate whether there even is a solid or liquid core or a mixture and advance the understanding of the thermal evolution of the moon and the solar system,” explained GRAIL co-investigator Sami Asmar to Universe Today. Asmar is from JPL.
New names for the dynamic duo may be announced on New Year’s Day. Zuber said that the winning names of a student essay contest drew more than 1000 entries.
The GRAIL team is making a major public outreach effort to involve school kids in the mission and inspire them to study science. Each spacecraft carries 4 MoonKAM cameras. Middle school students will help select the targets.
“Over 2100 Middle schools have already signed up to participate in the MoonKAM project,” Zuber told reporters.
“We’ve had a great response to the MoonKAM project and we’re still accepting applications.”
MoonKAM is sponsored by Dr. Sally Ride, America’s first female astronaut. The first images are expected after the science mission begins in March 2012.
The GRAIL twins blasted off from Florida on September 10, 2011 for a 3.5 month low energy path to the moon so a smaller booster rocket could be used to cut costs.
GRAIL team at JPL Mission Control await GRAIL-A Lunar Orbit Insertion on New Year’s Eve. David Lehman, GRAIL Project Manager of JPL, Prof Maria Zuber, GRAIL Principal Investigator of MIT. Credit: NASA/Jim GreenGRAIL Science and Launch teams inside clean room at Astrotech. Credit: Ken KremerGRAIL-A and GRAIL-B twin spacecraft inside clean room at Astrotech
GRAIL Co-Investigator Sami Asmar (left) from JPL and Ken Kremer discuss science objectives inside Astrotech clean room prior to encapsulation for launch. Credit: Ken Kremer
Dawn Orbiting Vesta. NASA's Dawn spacecraft achieved orbit at the giant asteroid Vesta in July 2011. The depiction of Vesta is based on images obtained by Dawn's framing cameras. Dawn is an international collaboration of the US, Germany and Italy. Credit: NASA/JPL-Caltech
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A year ago, 2011 was proclaimed as the “Year of the Solar System” by NASA’s Planetary Science division. And what a year of excitement it was indeed for the planetary science community, amateur astronomers and the general public alike !
NASA successfully delivered astounding results on all fronts – On the Story of How We Came to Be.
“2011 was definitely the best year ever for NASA Planetary Science!” said Jim Green in an exclusive interview with Universe Today. Green is the Director of Planetary Science for the Science Mission Directorate at NASA HQ. “The Search for Life is a significant priority for NASA.”
This past year was without doubt simply breathtaking in scope in terms of new missions, new discoveries and extraordinary technical achievements. The comprehensive list of celestial targets investigated in 2011 spanned virtually every type of object in our solar system – from the innermost planet to the outermost reaches nearly touching interplanetary space.
There was even a stunningly evocative picture showing “All of Humanity” – especially appropriate now in this Holiday season ! You and all of Humanity are here !
-- Earth & Moon Portrait by Juno from 6 Million miles away --
First Photo transmitted from Jupiter Bound Juno shows Earth (on the left) and the Moon (on the right). Taken on Aug. 26, 2011 when spacecraft was about 6 million miles (9.66 million kilometers) away from Earth. Credit: NASA/JPL-Caltech
Three brand new missions were launched and ongoing missions orbited a planet and an asteroid and flew past a comet.
“NASA has never had the pace of so many planetary launches in such a short time,” said Green.
And three missions here were awarded ‘Best of 2011’ for innovation !
Mars Science Laboratory (MSL), Dawn and MESSENGER named “Best of What’s New” in 2011 by Popular Science magazine. 3 NASA Planetary Science missions received the innovation award for 2011 from Popular Science magazine. Artist concept shows mosaic of MESSENGER, Mars Science Laboratory and Dawn missions. Credit: NASA/JPL-Caltech
Here’s the Top NASA Planetary Science Stories of 2011 – ‘The Year of the Solar System’ – in chronological order
1. Stardust-NExT Fly By of Comet Tempel 1
Starting from the first moments of 2011 at the dawn of Jan. 1, hopes were already running high for planetary scientists and engineers busily engaged in setting up a romantic celestial date in space between a volatile icy comet and an aging, thrusting probe on Valentine’s Day.
The comet chasing Stardust-Next spacecraft successfully zoomed past Comet Tempel 1 on Feb. 14 at 10.9 km/sec (24,000 MPH) after flying over 6 Billion kilometers (3.5 Billion mi).
6 Views of Comet Tempel 1 and Deep Impact crater during Stardust-NExT flyby on Feb. 14, 2011
Arrows show location of man-made crater created in 2005 by NASA’s prior Deep Impact comet mission and newly imaged as Stardust-NExT zoomed past comet in 2011. The images progress in time during closest approach to comet beginning at upper left and moving clockwise to lower left. Credit: NASA/JPL-Caltech/University of Maryland. Post process and annotations by Marco Di Lorenzo & Kenneth Kremer
The craft approached within 178 km (111mi) and snapped 72 astonishingly detailed high resolution science images over barely 8 minutes. It also fulfilled the teams highest hopes by photographing the human-made crater created on Tempel 1 in 2005 by a cosmic collision with a penetrator hurled by NASA’s Deep Impact spacecraft. The probe previously flew by Comet Wild 2 in 2004 and returned cometary coma particles to Earth in 2006
Tempel 1 is the first comet to be visited by two spaceships from Earth and provided the first-ever opportunity to compare observations on two successive passages around the Sun.
Don Brownlee, the original Principal Investigator, summarized the results for Universe Today; “A great bonus of the mission was the ability to flyby two comets and take images and measurements. The wonderfully successful flyby of Comet Tempel 1 was a great cap to the 12 year mission and provided a great deal of new information to study the diversity among comets.”
“The new images of Tempel showed features that form a link between seemingly disparate surface features of the 4 comets imaged by spacecraft. Combining data on the same comet from the Deep Impact and Stardust missions has provided important new insights in to how comet surfaces evolve over time and how they release gas and dust into space”.
2. MESSENGER at Mercury
On March 18, the Mercury Surface, Space Environment, Geochemistry, and Ranging, or MESSENGER, spacecraft became the first spacecraft inserted into orbit around Mercury, the innermost planet.
So far MESSENGER has completed 1 solar day – 176 Earth days- circling above Mercury. The probe has collected a treasure trove of new data from the seven instruments onboard yielding a scientific bonanza; these include global imagery of most of the surface, measurements of the planet’s surface chemical composition, topographic evidence for significant amounts of water ice, magnetic field and interactions with the solar wind.
“MESSENGER discovered that Mercury has an enormous core, larger than Earth’s. We are trying to understand why that is and why Mercury’s density is similar to Earth’s,” Jim Green explained to Universe Today.
The First Solar Day
After its first Mercury solar day (176 Earth days) in orbit, MESSENGER has nearly completed two of its main global imaging campaigns: a monochrome map at 250 m/pixel and an eight-color, 1-km/pixel color map. Small gaps will be filled in during the next solar day. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
“The primary mission lasts 2 solar days, equivalent to 4 Mercury years.”
“NASA has granted a 1 year mission extension, for a total of 8 Mercury years. This will allow the team to understand the environment at Mercury during Solar Maximum for the first time. All prior spacecraft observations were closer to solar minimum,” said Green.
MESSENGER was launched in 2004 and the goal is to produce the first global scientific observations of Mercury and piece together the puzzle of how Mercury fits in with the origin and evolution of our solar system.
NASA’s Mariner 10 was the only previous robotic probe to explore Mercury, during three flyby’s back in the mid-1970’s early in the space age.
3. Dawn Asteroid Orbiter
The Dawn spacecraft achieved orbit around the giant asteroid Vesta in July 2011 after a four year interplanetary cruise and began transmitting the history making first ever close-up observations of the mysteriously diverse and alien world that is nothing short of a ‘Space Spectacular’.
“We do not have a good analog to Vesta anywhere else in the Solar System,” Chris Russell said to Universe Today. Russell, from UCLA, is the scientific Principal Investigator for Dawn.
Before Dawn, Vesta was just another fuzzy blob in the most powerful telescopes. Dawn has completely unveiled Vesta as a remarkably dichotomous, heavily battered and pockmarked world that’s littered with thousands of craters, mountains and landslides and ringed by mystifying grooves and troughs. It will unlock details about the elemental abundances, chemical composition and interior structure of this marvelously intriguing body.
Cataclysmic collisions eons ago excavated Vesta so it lacks a south pole. Dawn discovered that what unexpectedly remains is an enormous mountain some 16 miles (25 kilometers) high, twice the height of Mt. Everest.
Dawn is now about midway through its 1 year mission at Vesta which ends in July 2012 with a departure for Ceres, the largest asteroid. So far the framing cameras have snapped more than 10,000 never-before-seen images.
“What can be more exciting than to explore an alien world that until recently was virtually unknown!. ” Dr. Marc Rayman said to Universe Today. Rayman is Dawn’s Chief Engineer from NASA’s Jet Propulsion Lab (JPL) in Pasadena, Calif.
“Dawn is NASA at its best: ambitious, exciting, innovative, and productive.”
4. Juno Jupiter Orbiter
The solar powered Juno spacecraft was launched on Aug. 5 at Cape Canaveral Air Force Station in Florida, to embark on a five year, 2.8 billion kilometer (1.7 Billion mi) trek to Jupiter, our solar system’s largest planet. It was the first of three NASA planetary science liftoffs scheduled in 2011.
Juno Jupiter Orbiter soars skyward to Jupiter on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer
Juno’s goal is to map to the depths of the planets interior and elucidate the ingredients of Jupiter’s genesis hidden deep inside. These measurements will help answer how Jupiter’s birth and evolution applies to the formation of the other eight planets.
The 4 ton spacecraft will arrive at the gas giant in July 2016 and fire its braking rockets to go into a polar orbit and circle the planet 33 times over about one year.
The suite of nine instruments will scan the gas giant to find out more about the planets origins, interior structure and atmosphere, measure the amount of water and ammonia, observe the aurora, map the intense magnetic field and search for the existence of a solid planetary core.
“Jupiter is the Rosetta Stone of our solar system,” said Scott Bolton, Juno’s principal investigator from the Southwest Research Institute in San Antonio. “It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary — to interpret what Jupiter has to say.”
5. Opportunity reaches Endeavour Crater on Mars
The long lived Opportunity rover finally arrived at the rim of the vast 14 mile (22 kilometer) wide Endeavour Crater in mid-August 2011 following an epic three year trek across treacherous dune fields – a feat once thought unimaginable. All told, Opportunity has driven more than 34 km ( 21 mi) since landing on the Red Planet way back in 2004 for a mere 90 sol mission.
Endeavour Crater Panorama from Opportunity Mars Rover in August 2011
Opportunity arrived at the rim of Endeavour on Sol 2681, August 9, 2011 after a three year trek. The robot photographed segments of the huge craters eroded rim in this panoramic vista. Endeavour Crater is 14 miles (22 kilometers) in diameter. Mosaic Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Kenneth Kremer
In November, the rover discovered the most scientifically compelling evidence yet for the flow of liquid water on ancient Mars in the form of a water related mineral vein at a spot dubbed “Homestake” along an eroded ridge of Endeavour’s rim.
Read my story about the Homestake discovery here, along with our panoramic mosaic showing the location – created by Ken Kremer and Marco Di Lorenzo and published by Astronomy Picture of the Day (APOD) on 12 Dec. 2011.
Watch for my upcoming story detailing Opportunity’s accomplishments in 2011.
6. GRAIL Moon Mappers
The Gravity Recovery and Interior Laboratory, or GRAIL mission is comprised of twin spacecraft tasked to map the moon’s gravity and study the structure of the lunar interior from crust to core.
Twin GRAIL Probes GO for Lunar Orbit Insertion on New Year’s Eve and New Year’s Day
GRAIL spacecraft will map the moon's gravity field and interior composition. Credit: NASA/JPL-Caltech
The dynamic duo lifted off from Cape Canaveral on September 10, 2011 atop the last Delta II rocket that will likely soar to space from Florida. After a three month voyage of more than 2.5 million miles (4 million kilometers) since blastoff, the two mirror image GRAIL spacecraft dubbed Grail-A and GRAIL-B are sailing on a trajectory placing them on a course over the Moon’s south pole on New Year’s weekend.
Each spacecraft will fire the braking rockets for about 40 minutes for insertion into Lunar Orbit about 25 hours apart on New Year’s Eve and New Year’s Day.
Engineers will then gradually lower the satellites to a near-polar near-circular orbital altitude of about 34 miles (55 kilometers).
The spacecraft will fly in tandem and the 82 day science phase will begin in March 2012.
“GRAIL is a Journey to the Center of the Moon”, says Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology (MIT). “GRAIL will rewrite the book on the formation of the moon and the beginning of us.”
“By globally mapping the moon’s gravity field to high precision scientists can deduce information about the interior structure, density and composition of the lunar interior. We’ll evaluate whether there even is a solid or liquid core or a mixture and advance the understanding of the thermal evolution of the moon and the solar system,” explained co-investigator Sami Asmar to Universe Today. Asmar is from NASA’s Jet Propulsion Laboratory (JPL)
7. Curiosity Mars Rover
The Curiosity Mars Science Lab (MSL) rover soared skywards on Nov. 26, the last of 2011’s three planetary science missions. Curiosity is the newest, largest and most technologically sophisticated robotic surveyor that NASA has ever assembled.
“MSL packs the most bang for the buck yet sent to Mars.” John Grotzinger, the Mars Science Laboratory Project Scientist of the California Institute of Technology, told Universe Today.
The three meter long robot is the first astrobiology mission since the Viking landers in the 1970’s and specifically tasked to hunt for the ‘Ingredients of Life’ on Mars – the most Earth-like planet in our Solar System.
Video caption: Action packed animation depicts sequences of Curiosity departing Earth, the nail biting terror of the never before used entry, descent and landing on the Martian surface and then looking for signs of life at Gale Crater during her minimum two year expedition across hitherto unseen and unexplored Martian landscapes, mountains and craters. Credit: NASA
Curiosity will gather and analyze samples of Martian dirt in pursuit of the tell-tale signatures of life in the form of organic molecules – the carbon based building blocks of life as we know it.
NASA is targeting Curiosity to a pinpoint touch down inside the 154 km (96 mile) wide Gale Crater on Aug. 6, 2012. The crater exhibits exposures of phyllosilicates and other minerals that may have preserved evidence of ancient or extant Martian life and is dominated by a towering 3 mile (5 km) high mountain.
“10 science instruments are all aimed at a mountain whose stratigraphic layering records the major breakpoints in the history of Mars’ environments over likely hundreds of millions of years, including those that may have been habitable for life,” Grotzinger told me.
Titan Upfront
The colorful globe of Saturn's largest moon, Titan, passes in front of the planet and its rings in this true color snapshot from NASA's Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science InstituteCuriosity Mars Science Laboratory Rover and Ken Kremer - inside the Cleanroom at the Kennedy Space Center. Last View of Curiosity just prior to folding and encapsulation for launch. Credit: Ken Kremer
This past year Ken was incredibly fortunate to witness the ongoing efforts of many of these magnificent endeavors.
West wall of Aristarchus crater seen obliquely by the LROC NACs from an altitude of only 26 km. Scene is about 12 km wide at the base. Credit: NASA/GSFC/Arizona State University.
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Have you ever you looked up at the bright, cavernous Aristarchus Crater on the Moon through a telescope or binoculars and wondered what it would be like to stand on the rim and peer inside? Spectacular new views from the Lunar Reconnaissance Orbiter is almost as good as being there, and a new video lets you “rappel” down and take a closer look at the west side of the crater walls.
Full panoramic view of the west wall of Aristarchus crater revealing impact melt deposits, exposures of high reflectance anorthosite, streamers of pyroclastic ash, and blocks up to 100 meters in size. Full width of panorama is about 25 km. Credit: NASA/GSFC/Arizona State University.
LRO Camera Principal Investigator Mark Robinson describes the region around the crater, known as the Aristarchus plateau, as one of the most geologically diverse places on the Moon. “A mysterious raised flat plateau, a giant rille carved by enormous outpourings of lava, fields of explosive volcanic ash, and all surrounded by massive flood basalts,” Robinson wrote on the LROC website. “A relatively recent asteroid (or comet) slammed into this geologic wonderland, blowing a giant hole in the ground revealing a cross section of over 3,000 meters (9,800 ft) of geology. No wonder planners for the Apollo missions put this plateau high on its list of targets for human exploration.”
These new amazing images were acquired on November 10, 2011 as LRO passed only 26 km (16.2 miles) above the surface, which is about two times lower than normal, due to LRO’s current elliptical orbit. The spacecraft was slewed to the west for an oblique or “sideways” look at the crater, instead of looking straight down as LRO normally does, to provide this unique perspective on Aristarchus. For a sense of scale, Robinson said that altitude is only a little over twice as high as commercial jets fly above the Earth. This crater is only one-tenth the size of Earth’s Grand Canyon, but the views from up above are similarly spectacular.
The location of Aristarchus Crater. Credit: Wikipedia
Aristarchus crater is located on the southeast edge of the Aristarchus Plateau. This yawning crater is 40 km wide and 3.5 km deep. The edges appear scalloped, almost like it crater was strip-mined. Since the crater is relatively young, Aristarchus is one of the brightest regions on the Moon. Robinson says these bright rocks may be anorthositic like the highlands, or they may be a more silicic rock like granite — or both.
“Although granites have been found in Apollo rock samples, the formation of granite on the Moon is not well understood at this time – another reason why we need to get samples from this region,” he said.
A 'straight down' view of Aristarchus, Aristarchus crater.. Small white arrows indicate approximate corners of the NAC panorama. Vertical line on right shows LRO orbit ground track Credit: NASA/GSFC/Arizona State University.
From this ‘straight down’ view, you can see the bright ejecta, contrasted by darker areas, which reflects the compositional difference between the various rocks in the region.
On the floor of Aristarchus crater is a wide variety of lunar rocks and geologic processes.
“Diverse materials such as dark, multilayered mare basalts in the walls, bright crustal rocks in the central peak, impact melt, and even regional pyroclastic materials blanketing the crater are brought to the floor and accumulated through mass wasting, creating a bountiful trove of geologic materials,” Robinson said.
The "Blair Cuspids" spires photographed by Lunar Orbiter 2 in 1966. Credit: NASA
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Two researchers at Arizona State University (ASU) have made a rather controversial proposal: have the public and other researchers study the high-resolution photographs of the Moon already being taken by the Lunar Reconnaissance Orbiter (LRO), to look for anomalies that may possibly be evidence of artifacts leftover from previous alien visitation. The theory is that if our solar system had been visited in the past, the Moon would have made an ideal base from which to study the Earth. The paper has just been recently published in the journal Acta Astronautica.
Professor Paul Davies and research technician Robert Wagner admit that the chances of success are very small, but argue that the endeavour would be worth the minimal investment required. The photographs are already being taken on a regular basis by LRO. Any interesting finds could be examined by others including imaging professionals. Shape-recognizing software could also be used to help discern any possible artificial artifacts from natural ones.
From the abstract:
The Search for Extraterrestrial Intelligence (SETI) has a low probability of success, but it would have a high impact if successful. Therefore it makes sense to widen the search as much as possible within the confines of the modest budget and limited resources currently available. To date, SETI has been dominated by the paradigm of seeking deliberately beamed radio messages.
However, indirect evidence for extraterrestrial intelligence could come from any incontrovertible signatures of non-human technology. Existing searchable databases from astronomy, biology, earth and planetary sciences all offer low-cost opportunities to seek a footprint of extraterrestrial technology. In this paper we take as a case study one particular new and rapidly-expanding database: the photographic mapping of the Moon’s surface by the Lunar Reconnaissance Orbiter (LRO) to 0.5 m resolution. Although there is only a tiny probability that alien technology would have left traces on the moon in the form of an artifact or surface modification of lunar features, this location has the virtue of being close, and of preserving traces for an immense duration.
Systematic scrutiny of the LRO photographic images is being routinely conducted anyway for planetary science purposes, and this program could readily be expanded and outsourced at little extra cost to accommodate SETI goals, after the fashion of the SETI@home and Galaxy Zoo projects.
Of course, it has been said by some that such artifacts have already been found and known about for decades but hidden from the public by NASA, et al. An entire cottage industry has grown around this idea. There are actually a handful of anomalies from various missions that would be interesting to see at much higher resolution via LRO, such as the well-known “Blair Cuspids” photographed by Lunar Orbiter 2 in 1966, although by far most unusual-looking objects are easily explained. It’s the same problem as with Mars; so many anomalies found by amateur observers are the product of pareidolia, lighting effects, image defects or even geology. Separating out any genuine anomalies from all of the noise would be a tedious and time-consuming task. On the other hand, we now have much better cameras in orbit around the Moon (and Mars) and more advanced photographic analysis techniques available.
Yes, the chances of finding anything are very small, maybe even nonexistent in the opinion of some, but if we have the images being taken anyway, and the willingness of some to study them, then why not? If nothing is found, no harm done. It something was found, well that’s another story entirely…
The abstract for the paper is here. (The paper itself costs $31.50 US to download).
GRAIL probes uses precision formation-flying technique to map Lunar Gravity. The twin GRAIL spacecraft will map the moon's gravity field, as depicted in this artist's rendering. Radio signals traveling between the two spacecraft provide scientists the exact measurements required as well as flow of information not interrupted when the spacecraft are at the lunar farside, not seen from Earth. The result should be the most accurate gravity map of the moon ever made. The mission also will answer longstanding questions about Earth's moon, including the size of a possible inner core, and it should provide scientists with a better understanding of how Earth and other rocky planets in the solar system formed. GRAIL is a part of NASA's Discovery Program. Credit: NASA/JPL-Caltech
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In less than three days, NASA will deliver a double barreled New Year’s package to our Moon when an unprecedented pair of science satellites fire up their critical braking thrusters for insertion into lunar orbit on New Year’s Eve and New Year’s Day.
NASA’s dynamic duo of GRAIL probes are “GO” for Lunar Orbit Insertion said the mission team at a briefing for reporters today, Dec. 28. GRAIL’s goal is to exquisitely map the moons interior from the gritty outer crust to the depths of the mysterious core with unparalled precision.
“GRAIL is a Journey to the Center of the Moon”, said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology (MIT) in Cambridge at the press briefing.
This newfound knowledge will fundamentally alter our understanding of how the moon and other rocky bodies in our solar system – including Earth – formed and evolved over 4.5 Billion years time.
After a three month voyage of more than 2.5 million miles (4 million kilometers) since launching from Florida on Sept. 10, 2011, NASA’s twin GRAIL spacecraft, dubbed Grail-A and GRAIL-B, are now on final approach and are rapidly closing in on the Moon following a trajectory that will hurl them low over the south pole and into an initially near polar elliptical lunar orbit lasting 11.5 hours.
GRAIL's trajectory to moon since Sept. 10, 2011 blastoff
Credit: NASA/JPL-Caltech
As of today, Dec. 28, GRAIL-A is 65,860 miles (106,000 kilometers) from the moon and closing at a speed of 745 mph (1,200 kph). GRAIL-B is 79,540 miles (128,000 kilometers) from the moon and closing at a speed of 763 mph (1,228 kph).
The lunar bound probes are formally named Gravity Recovery And Interior Laboratory (GRAIL) and each one is the size of a washing machine.
The long-duration trajectory was actually beneficial to the mission controllers and the science team because it permitted more time to assess the spacecraft’s health and check out the probes single science instrument – the Ultra Stable Oscillator – and allow it to equilibrate to a stable operating temperature long before it starts making the crucial science measurements.
NASA’s twin GRAIL A & B Moon mapping probes
The GRAIL satellites are now streaking to the Moon and their arrival for orbit insertion is just days away and hours apart on New Year’s Eve and New Year’s Day 2012. This picture shows how they looked, mounted side by side, during launch preparations inside the clean room at Astrotech Space Operations facility in Florida prior to blasting off for the Moon on Sept. 10, 2011 from Cape Canaveral, Florida. Credit: Ken Kremer
The duo will arrive 25 hours apart and be placed into orbit starting at 1:21 p.m. PST (4:21 p.m. EST) for GRAIL-A on Dec. 31, and 2:05 p.m. PST (5:05 p.m. EST) on Jan. 1 for GRAIL-B, said David Lehman, project manager for GRAIL at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
“The GRAIL A burn will last 40 minutes and the GRAIL-B burn will last 38 minutes. One hour after the burn we will know the results and make an announcement,” Lehman explained.
The thrusters must fire on time and for the full duration for the probes to achieve orbit. The braking maneuver is preprogrammed and done completely automatically.
Over the next few weeks, the altitude of the spacecraft will be gradually lowered to 34 miles (55 kilometers) into a near-polar, near-circular orbit with an orbital period of two hours. The science phase will then begin in March 2012.
“So far there have been over 100 missions to the Moon and hundreds of pounds of rock have been returned. But there is still a lot we don’t know about the Moon even after the Apollo lunar landings,” explained Zuber.
“We don’t know why the near side of the Moon is different from the far side. In fact we know more about Mars than the Moon.”
GRAIL’s science collection phase will last 82 days. The two spacecraft will transmit radio signals that will precisely measure the distance between them to within a few microns, less than the width of a human hair.
Artist concept of twin GRAIL spacecraft flying in tandem orbits around the moon to measure its gravity field in unprecedented detail. Credit: NASA/JPL
As they orbit in tandem, the moons gravity will change – increasing and decreasing due to the influence of both visible surface features such as mountains and craters and unknown concentrations of masses hidden beneath the lunar surface. This will cause the relative velocity and the distance between the probes to change.
The resulting data will be translated into a high-resolution map of the Moon’s gravitational field and also enable determinations of the moon’s inner composition.
The GRAIL mission may be extended for another 6 months if the solar powered probes survive a power draining and potentially deadly lunar eclipse due in June 2012.
Engineers would significantly lower the orbit to an altitude of barely 15 to 20 miles above the surface to gain even further insights into the lunar interior.
The twin probes are also equipped with 4 cameras each – named MoonKAM – that will be used by middle school students to photograph student selected targets.
The MoonKAM project is led Dr. Sally Ride, America’s first woman astronaut as a way to motivate kids to study math and science.
JPL manages the GRAIL mission for NASA.
Stay tuned for Universe Today updates amidst the News Year’s festivities.
Blastoff of twin GRAIL A and B lunar gravity mapping spacecraft on a Delta II Heavy rocket on Sept. 10 from Pad 17B Cape Canaveral Air Force Station in Florida at 9:08 a.m. EDT. Credit: Ken Kremer
The Earth and Moon as seen from Mariner 10 en route to Venus. This could be a similar view of two moons as seen from Earth. Image credit: NASA/courtesy of nasaimages.org
But what if the Earth actually had a second permanent moon today? How different would life be? Astronomer and physicist Neil F. Comins delves into this thought experiment, and suggests some very interesting consequences.
This shot of Io orbiting Jupiter shows the scale between other moons and their planet. Image credit:NASA/courtesy of nasaimages.org
Our Earth-Moon system is unique in the solar system. The Moon is 1/81 the mass of Earth while most moons are only about 3/10,000 the mass of their planet. The size of the Moon is a major contributing factor to complex life on Earth. It is responsible for the high tides that stirred up the primordial soup of the early Earth, it’s the reason our day is 24 hours long, it gives light for the variety of life forms that live and hunt during the night, and it keeps our planet’s axis tilted at the same angle to give us a constant cycle of seasons.
A second moon would change that.
For his two-mooned Earth thought experiment, Comins proposes that our Earth-Moon system formed as it did — he needs the same early conditions that allowed life to form — before capturing a third body. This moon, which I will call Luna, sits halfway between the Earth and the Moon.
Luna’s arrival would wreak havoc on Earth. Its gravity would tug on the planet causing absolutely massive tsunamis, earthquakes, and increased volcanic activity. The ash and chemicals raining down would cause a mass extinction on Earth.
But after a few weeks, things would start to settle.
Luna would adjust to its new position between the Earth and the Moon. The pull from both bodies would cause land tides and volcanic activity on the new moon; it would develop activity akin to Jupiter’s volcanic moon Io. The constant volcanic activity would make Luna smooth and uniform, as well as a beautiful fixture in the night sky.
New Horizons captured this image of volcanic activity on Io. The same sight could be seen of Luna from Earth. Image credit: NASA/courtesy of nasaimages.org
The Earth would also adjust to its two moons, giving life a chance to arise. But life on a two-mooned Earth would be different.
The combined light from the Moon and Luna would make for much brighter nights, and their different orbital periods will mean the Earth would have fewer fully dark nights. This will lead to different kinds of nocturnal beings; nighttime hunters would have an easier time seeing their prey, but the prey would develop better camouflage mechanisms. The need to survive could lead to more cunning and intelligent breeds of nocturnal animals.
Humans would have to adapt to the challenges of this two-mooned Earth. The higher tides created by Luna would make shoreline living almost impossible — the difference between high and low tides would be measured in thousands of feet. Proximity to the water is a necessity for sewage draining and transport of goods, but with higher tides and stronger erosion, humans would have to develop different ways of using the oceans for transfer and travel. The habitable area of Earth, then, would be much smaller.
The measurement of time would also be different. Our months would be irrelevant. Instead, a system of full and partials months would be necessary to account for the movement of two moons.
A scale comparison of the Earth, the Moon, and Jupiter’s largest moons (the Jovian moons). Image credit:Image Credit: NASA/courtesy of nasaimages.org
Eventually, the Moon and Luna would collide; like the Moon is now, both moons would be receding from Earth. Their eventual collision would send debris raining through Earth’s atmosphere and lead to another mass extinction. The end result would be one moon orbiting the Earth, and life another era of life would be primed to start.
A waning crescent Moon on Dec. 22, 2011 from British Columbia. Credit: Suraky
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A beautiful crescent Moon graced the morning and evening skies over the past holiday weekend, and skywatchers around the world were out with with their cameras! Above, Suraky from British Columbia, Canada took this lovely image of the waning sliver of the Moon from his bedroom window. “The Moon was lit by Earthshine on the dark side, at 7am, with Baker poking out between the trees,” he commented on the image.
See more from other astrophotographers below.
The crescent Moon and Ashby's Mill in the UK. Credit: Owen Llewellyn
Owen Llewellyn from the UK shared this beautiful shot, taken on Dec. 26, 2011.
Mercury showed up in the twilight colors few degrees above a wonderful 4% slender crescent Moon “close” to the Basilica of Superga. Credit: Stefano De Rosa
Stefano De Rosa took this image on Dec. 23, 2011 showing the crescent Moon hovering over the Bascilica of Superga in Turin, Italy.
A tiny sliver of the crescent Moon is barely visible in this image taken on Dec. 26, 2011 at Hernesaari, Helsinki, Finland. Credit: Otto J. Mäkelä
Otto J. Mäkelä from Finland shared this image via Twitter.
xtremely thin lunar crescent (1% lit, 22hrs old) seen from Croatia on Dec. 25, 2011. Credit: Marko Posavec in Koprivnica, Croatia.
Marko Posavec from Croatia also sent this one via Twitter of a very thin lunar crescent.
Want to get your astrophoto featured on Universe Today? Join our Flickr group, post in our Forum or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
