Yuri Gagarin on the way to his historic Vostok launch on April 12, 1961. Image: NASA
On the morning of April 12, 1961, Soviet cosmonaut Yuri Gagarin lifted off aboard Vostok 1 to become the first human in space, spending 108 minutes in orbit before landing via parachute in the Saratov region of the USSR. The soft-spoken and well-mannered Gagarin, just 27 years old at the time, became an instant hero, representing the success of the Soviet space program (Alan Shepard’s shorter, suborbital flight happened less than a month later) to the entire world. Gagarin later went on to become a director for the Cosmonaut Training Center and was preparing for a second space flight. Tragically, he was killed when a MiG-15 aircraft he was piloting crashed on March 27, 1968.
Gagarin’s death has long been shrouded by confusion and controversy, with many theories proposed as to the actual cause. Now, 45 years later, details about what really happened to cause the death of the first man in space have come out — from the first man to go out on a spacewalk, no less.
Televised image of Aleksey Leonov during his spacewalk outside Vokshod 2
According to an article published online today on Russia Today (RT.com) former cosmonaut Aleksey Leonov — who performed the first EVA on March 18, 1965 — has revealed details about the accident that killed both Yuri Gagarin and his flight instructor Vladimir Seryogin in March 1968.
Officially the cause of the crash was said to be the ill-fated result of an attempt to avoid a foreign object during flight training in their MiG-15UTI, a two-seated, dual-controlled training version of the widely-produced Soviet aircraft. “Foreign objects” could be anything, from balloons to flocks of birds to airborne debris to… well, you see where one could go with that. (And over the years many have.)
The maneuver led to the aircraft going into a tailspin and crashing, killing both men. But experienced pilots like Gagarin and Seryogin shouldn’t have lost control of their plane like that — not according to Leonov, who has been trying to release details of the event for the past 20 years… if only that the pilots’ families might know the truth.
A Sukhoi Su-15 fighter jet (Wikipedia Commons)
Now, a declassified report, which Leonov has been permitted to share, shows what actually happened during the training flight: an “unauthorized Su-15 fighter” flew too close to Gagarin’s MiG, disrupting its flight and sending it into a spin.
“In this case, the pilot didn’t follow the book, descending to an altitude of 450 meters,” Leonov says in the RT.com article. “While afterburning the aircraft reduced its echelon at a distance of 10-15 meters in the clouds, passing close to Gagarin, turning his plane and thus sending it into a tailspin — a deep spiral, to be precise — at a speed of 750 kilometers per hour.”
The pilot of the Su-15 — who is still alive — was was not named, a condition of Leonov’s permission to share the information.
According to first woman in space Valentina Tereshkova, who was officially grounded by the government after Gagarin’s death to avoid a loss of another prominent cosmonaut, the details come as a bittersweet relief.
“The only regret here is that it took so long for the truth to be revealed,” Tereshkova said. “But we can finally rest easy.”
Tereshkova and Leonov at the Cosmonautics Museum in Moscow during a ceremony in 2011 celebrating the 50th anniversary of the launch of Yuri Gagarin. (NASA photo.)
The view when ATV-3 approached the ISS in 2012. Credit: NASA.
Recall how during a space shuttle mission, the astronauts were awoken each day with music radioed up from Mission Control? Now, ESA has started a tradition of creating a music video to celebrate various events, such as the docking of their Automated Transfer Vehicle. The ATV-4, named Albert Einstein, will dock with the International Space Station on Saturday, June 15 at 13:46 UTC (9:46 a.m. EDT, and here’s a little hip hop to get you in the mood.
ESA teamed up with hip hop group Ugly Duckling for a super space remix of the song “Elevation.”
The connection to the group and this ATV mission was perfect, as the long-time DJ for Ugly Duckling goes under the stage name DJ Young Einstein. ESA liked the group because they are known for their ‘old-school’ hip-hop with an upbeat message and non-violent lyrics.
TATV-4 is ferrying a record cargo of 6.6 tons to the ISS – food, fuel, water, oxygen, science experiments and undisclosed special treats for the six-member crew on the space station.
An artist's conception of a spacecraft designed to pick up an asteroid. Credit: NASA/Advanced Concepts Laboratory
In a few generations of robotics, we’ll see mighty machines able to fully construct themselves and operate from the surface of asteroids — providing applications for mining, NASA researchers say in a new study.
The scientists are convinced that this type of research is not only possible, but also able to support itself financially. (Costs overruns are a notorious factor in space exploration as it pushes frontiers both literally and engineering-wise.)
“Advances in robotics and additive manufacturing have become game-changing for the prospects of space industry. It has become feasible to bootstrap a self-sustaining, self-expanding industry at reasonably low cost,” the researchers stated in a new study.
A couple of factors are pointing to this, researchers said: private industry is willing and able to get involved. Advances in technologies such as 3-D printing are making off-world work more feasible. Also, humanity’s surveys of space resources has revealed the elements needed to make rubber, plastic and alloys needed for machinery.
NASA proposes a robotic flotilla could mine nearby space rocks. They caution the technology won’t be ready tomorrow, and more surveys will need to be done of nearby asteroids to figure out where to go next. There is, however, enough progress to see building blocks, the agency stated.
An artist’s conception of a space exploration vehicle approaching an asteroid. Credit: NASA
“Robots and machines would just make the metal and propellants for starters,” stated Phil Metzger, a senior research physicist at NASA’s Kennedy Space Center, who led the study.
“The first generation of robots makes the second generation of hardware, except the comparatively lightweight electronics and motors that have to be sent up from Earth. It doesn’t matter how much the large structures weigh because you didn’t have to launch it.”
A computer model in the study showed that in six generations of robotics, these machines will be able to construct themselves and operate without any need of materials from Earth.
Artist impression of the Arkyd Interceptor, a low cost asteroid mission that enables accelerated exploration. Credit: Planetary Resources.
In the past year, members of both firms have proposed asteroid mining ideas, and since then, Planetary Resources has also unveiled other projects such as a public space telescope (perhaps in a bid to diversify revenues and attract more attention.)
That’s received many questions from critics (including at least one government space committee), but NASA has argued it is feasible and a way to unite innovation across various sectors.
“Because asteroids are loaded with minerals that are rare on Earth, near-Earth asteroids and the asteroid belt could become the mining centers for remotely-operated excavators and processing machinery,” NASA stated.
Asteroid 951 Gaspra. Credit: NASA
“In the future, an industry could develop to send refined materials, rare metals and even free, clean energy to Earth from asteroids and other bodies.”
Curiosity’s hi tech ‘hand’ and percussion drill hovers above 2nd bore hole at Cumberland mudstone rock after penetrating laser blasting to unlock secrets of ancient flow of Martian water. Photo mosaic assembled from high resolution Mastcam images on May 21, 2013, Sol 281. Credit: NASA/JPL-Caltech/MSSS/Ken Kremer (kenkremer.com)/Marco Di Lorenzo
Ten months after her breathtaking touchdown on the Red Planet, NASA’s Curiosity rover is nearly set to embark on an epic drive like no other in space history to the slopes of mysterious Mount Sharp – looming supreme inside Gale Crater and the primary mission objective.
But not before the robot completes a few last critical science tasks to more fully illuminate the potential for the origin of Martian microbes in the habitable zone discovered at the work-site of her first penetrations into Mars water altered surface.
The rover science team has chosen a trio of final targets to investigate around the shallow basin of Yellowknife Bay, that resembles a dried out lakebed, where Curiosity has toiled for the past six months, drilled twice into the mudstone outcrops at ‘John Klein’ and ‘Cumberland’ and repeatedly fired her powerful science laser.
Curiosity will revisit a pair of intriguing outcrops named ‘Point Lake’ and ‘Shaler’ that the rover briefly investigated before arriving at ‘John Klein’, said Joy Crisp of JPL, Curiosity’s deputy project scientist, at a media briefing.
“Shaler might be a river deposit. Point Lake might be volcanic or sedimentary. A closer look at them could give us better understanding of how the rocks we sampled with the drill fit into the history of how the environment changed.”
Curiosity will employ nearly all her science instruments to study the outcrops – except the drill.
“It’s highly unlikely to drill at ‘Point Lake’ and ‘Shaler’ because we want to get driving,” Crisp told Universe Today.
“We might drill somewhere along the way to Mount Sharp depending on whether we find something compelling.”
‘Point Lake’ Outcrop in Gale Crater. A priority target for a closer look byCuriosity before the rover departs the “Glenelg” area east of its landing site. The pitted outcrop called “Point Lake” is about 7 feet (2 meters) wide and 20 inches (50 centimeters) high. A closer inspection may yield information about whether it is a volcanic or sedimentary deposit. Credit: NASA/JPL-Caltech/MSSS
Researchers will also use the DAN (Dynamic Albedo of Neutrons) instrument to look for traces of mineral bound water – in the form of hydrogen – at the boundary between bedrock areas of mudstone and sandstone.
Thereafter, Curiosity’s handlers will command the 1 ton behemoth to begin the drive to the lower reaches of Mount Sharp which lies about 6 miles (10 kilometers) distant – as the Martian crow flies.
Mount Sharp rises about 3.4 miles (5.5 km) from the center of Gale Crater. It’s taller than Mount Ranier in Washington State.
Billions of years of Mars geologic history are preserved in the sedimentary layers of Mount Sharp – along with potential signatures of the chemical ingredients of life.
Curiosity Route Map From ‘Glenelg’ to Mount Sharp.
This map shows where NASA’s Mars rover Curiosity landed in August 2012 at “Bradbury Landing”; the area where the rover worked from November 2012 through May 2013 at and near the “John Klein” target rock in the “Glenelg” area; and the mission’s next major destination, the entry point to the base of Mount Sharp. Credit: NASA/JPL-Caltech/Univ. of Arizona
“The drive will start in a few weeks,” said Curiosity Project Manager Jim Erickson of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. at the briefing.
But the team will be on the lookout for targets of opportunity along the way.
“We are on a mission of exploration. If we come across scientifically interesting areas, we are going to stop and examine them before continuing the journey,” Erikson added.
“If we pass something amazing and compelling we might turn around and drive back,” Crisp added.
It could take nearly a year to arrive at Mount Sharp. And Curiosity must pass through a potentially treacherous dune field to get there – see NASA JPL route map above.
“We are looking for the best path though,” said Erickson.
NASA chose Gale as the landing site specifically to dispatch Curiosity to investigate the sedimentary layers of Mount Sharp because it exhibited signatures of clay minerals that form in neutral water and that could possibly support the origin and evolution of simple Martian life forms, past or present.
“We have a real desire to get to Mount Sharp because there we see variations in the mineralogy as we go up from the base to higher levels and a change in the record of the environment,” said Crisp.
Analysis of the initial gray colored, powdery ‘John Klein’ sample by Curiosity’s pair of onboard chemistry labs – SAM & Chemin – revealed that this location on Mars was habitable in the past and possesses the key chemical ingredients – such as clay minerals – required to support microbial life forms- thereby successfully accomplishing the key science objective of the mission and making a historic discovery long before even arriving at destination Mount Sharp.
Besides the science measurements, researchers also learned lot about how to operate the complex drilling and sample delivery mechanisms much more efficiently for the second drilled rock sample.
The sieved and pulverized Cumberland sample was delivered in about a quarter of the time compared to the John Klein sample – accomplished at a deliberately measured and cautious pace.
Context view of Curiosity’s 2nd drill site at Cumberland rock on the floor of Yellowknife Bay basin showing ancient water altered rocks where the rover found environmental conditions favorable for microbial life. Mastcam images on May 23, 2013, Sol 283. Credit: NASA/JPL-Caltech/MSSS/Ken Kremer (kenkremer.com)/Marco Di Lorenzo
Analysis of the “Cumberland” powder is currently in progress. The goal is to determine how it compares chemically and to confirm the results found at ‘John Klein.’
“No results from Cumberland are available yet,” said Crisp.
The robot used the powerful million watt ChemCam laser to blast into the Cumberland drill hole and gray tailings scattered on the surface to glean as much insight and measurements of the chemical composition and transformation by water as possible before departing.
Curiosity has just arrived at “Point Lake’. Stay tuned for my next Curiosity story.
Meanwhile, Curiosity’s older sister rover Opportunity has likewise discovered clay minerals and a habitable zone on the opposite side of the Red Planet – details here.
And don’t forget to “Send Your Name to Mars” aboard NASA’s MAVEN orbiter- details here. Deadline: July 1, 2013
Learn more about Mars, Curiosity, Opportunity, MAVEN, LADEE and NASA missions at Ken’s upcoming lecture presentations
June 23: “Send your Name to Mars on MAVEN” and “CIBER Astro Sat, LADEE Lunar & Antares Rocket Launches from Virginia”; Rodeway Inn, Chincoteague, VA, 8 PM
This time lapse mosaic shows Curiosity moving her robotic arm to drill into her 2nd rockt target named “Cumberland” to collect powdery material on May 19, 2013 (Sol 279) for analysis by her onboard chemistry labs; SAM & Chemin. The photomosaic was stitched from raw images captured by the navcam cameras on May 14 & May 19 (Sols 274 & 279). Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo
This is a classic trick question. Ask a friend, “what is the closest star?” and then watch as they try to recall some nearby stars. Sirius maybe? Alpha something or other? Betelgeuse?
The answer, obviously, is the Sun; that massive ball of plasma located a mere 150 million km from Earth.
Let’s be more precise; what’s the closest star to the Sun?
Closest Star
You might have heard that it’s Alpha Centauri, the third brightest star in the sky, just 4.37 light-years from Earth.
But Alpha Centauri isn’t one star, it’s a system of three stars. First, there’s a binary pair, orbiting a common center of gravity every 80 years. Alpha Centauri A is just a little more massive and brighter than the Sun, and Alpha Centauri B is slightly less massive than the Sun. Then there’s a third member of this system, the faint red dwarf star, Proxima Centauri.
It’s the closest star to our Sun, located just a short 4.24 light-years away.
Proxima Centauri
Alpha Centauri is located in the Centaurus constellation, which is only visible in the Southern Hemisphere. Unfortunately, even if you can see the system, you can’t see Proxima Centauri. It’s so dim, you need a need a reasonably powerful telescope to resolve it.
Let’s get sense of scale for just how far away Proxima Centauri really is. Think about the distance from the Earth to Pluto. NASA’s New Horizons spacecraft travels at nearly 60,000 km/h, the fastest a spacecraft has ever traveled in the Solar System. It will have taken more than nine years to make this journey when it arrives in 2015. Travelling at this speed, to get to Proxima Centauri, it would take New Horizons 78,000 years.
Proxima Centauri has been the nearest star for about 32,000 years, and it will hold this record for another 33,000 years. It will make its closest approach to the Sun in about 26,700 years, getting to within 3.11 light-years of Earth. After 33,000 years from now, the nearest star will be Ross 248.
What About the Northern Hemisphere?
Bernard’s StarFor those of us in the Northern Hemisphere, the closest visible star is Barnard’s Star, another red dwarf in the constellation Ophiuchus. Unfortunately, just like Proxima Centauri, it’s too dim to see with the unaided eye.
The closest star that you can see with the naked eye in the Northern Hemisphere is Sirius, the Dog Star. Sirius, has twice the mass and is almost twice the size of the Sun, and it’s the brightest star in the sky. Located 8.6 light-years away in the constellation Canis Major – it’s very familiar as the bright star chasing Orion across the night sky in Winter.
How do Astronomers Measure the Distance to Stars?
They use a technique called parallax. Do a little experiment here. Hold one of your arms out at length and put your thumb up so that it’s beside some distant reference object. Now take turns opening and closing each eye. Notice how your thumb seems to jump back and forth as you switch eyes? That’s the parallax method.
To measure the distance to stars, you measure the angle to a star when the Earth is one side of its orbit; say in the summer. Then you wait 6 month, until the Earth has moved to the opposite side of its orbit, and then measure the angle to the star compared to some distant reference object. If the star is close, the angle will be measurable, and the distance can be calculated.
You can only really measure the distance to the nearest stars this way, since it only works to about 100 light-years.
The 20 Closest Stars
Here is a list of the 20 closest star systems and their distance in light-years. Some of these have multiple stars, but they’re part of the same system.
Alpha Centauri – 4.2
Barnard’s Star – 5.9
Wolf 359 – 7.8
Lalande 21185 – 8.3
Sirius – 8.6
Luyten 726-8 – 8.7
Ross 154 – 9.7
Ross 248 – 10.3
Epsilon Eridani – 10.5
Lacaille 9352 – 10.7
Ross 128 – 10.9
EZ Aquarii – 11.3
Procyon – 11.4
61 Cygni – 11.4
Struve 2398 – 11.5
Groombridge 34 – 11.6
Epison Indi – 11.8
Dx Carncri – 11.8
Tau Ceti – 11.9
GJ 106 – 11.9
According to NASA data, there are 45 stars within 17 light years of the Sun. There are thought to be as many as 200 billion stars in our galaxy. Some are so faint that they are nearly impossible to detect. Maybe, with technological improvements, scientists will find even closer stars.
Dark lightning occurs within thunderstorms and flings gamma rays and antimatter into space. (Science@NASA video)
Discovered “by accident” by NASA’s Fermi Gamma-ray Space Telescope in 2010, dark lightning is a surprisingly powerful — yet invisible — by-product of thunderstorms in Earth’s atmosphere. Like regular lightning, dark lightning is the result of a natural process of charged particles within storm clouds trying to cancel out opposing charges. Unlike normal lightning, though, dark lightning is invisible to our eyes and doesn’t radiate heat or light — instead, it releases bursts of gamma radiation.
What’s more, these gamma-ray outbursts originate at relatively low altitudes well within the storm clouds themselves. This means that airplane pilots and passengers flying through thunderstorms may be getting exposed to gamma rays from dark lightning, which are energetic enough to pass through the hull of an aircraft… as well as anything or anyone inside it. To find out how such exposure to dark lightning could affect air travelers, the U.S. Naval Research Laboratory (NRL) is conducting computer modeling tests using their SoftWare for the Optimization of Radiation Detectors — SWORD, for short.
Terrestrial Gamma-ray Flashes (TGFs) are extremely intense, sub-millisecond bursts of gamma rays and particle beams of matter and anti-matter. First identified in 1994, they are associated with strong thunderstorms and lightning, although scientists do not fully understand the details of the relationship to lightning. The latest theoretical models of TGFs suggest that the particle accelerator that creates the gamma rays is located deep within the atmosphere, at altitudes between six and ten miles, inside thunderclouds and within reach of civilian and military aircraft.
These models also suggest that the particle beams are intense enough to distort and collapse the electric field within thunderstorms and may, therefore, play an important role in regulating the production of visible lightning. Unlike visible lightning, TGF beams are sufficiently broad — perhaps about half a mile wide at the top of the thunderstorm — that they do not create a hot plasma channel and optical flash; hence the name, “dark lightning.”
A team of NRL Space Science Division researchers, led by Dr. J. Eric Grove of the High Energy Space Environment (HESE) Branch, is studying the radiation environment in the vicinity of thunderstorms and dark lightning flashes. Using the Calorimeter built by NRL on NASA’s Fermi Gamma-ray Space Telescope they are measuring the energy content of dark lightning and, for the first time, using gamma rays to geolocate the flashes.
As a next step, Dr. Chul Gwon of the HESE Branch is using NRL’s SoftWare for the Optimization of Radiation Detectors (SWORD) to create the first-ever simulations of a dark lightning flash striking a Boeing 737. He can calculate the radiation dosage to the passengers and crew from these Monte Carlo simulations. Previous estimates have indicated it could be as high as the equivalent of hundreds of chest X-rays, depending on the intensity of the flash and the distance to the source.
Simulation of a Boeing 737 struck by dark lightning. Green tracks show the paths of gamma rays from the dark flash as they enter the aircraft from below. (Credit: U.S. Naval Research Laboratory)
SWORD simulations allow researchers to study in detail the effects of variation in intensity, spectrum, and geometry of the flash. Dr. Grover’s team is now assembling detectors that will be flown on balloons and specialized aircraft into thunderstorms to measure the gamma ray flux in situ. The first balloon flights are scheduled to take place this summer.
An image of TW Hydrae and the protoplanetary stuff surrounding the star. Astronomers believe a planet is forming within the gas and dust and sweeping up debris, as shown by the gap in this picture. Credit: NASA, ESA, J. Debes (STScI), H. Jang-Condell (University of Wyoming), A. Weinberger (Carnegie Institution of Washington), A. Roberge (Goddard Space Flight Center), and G. Schneider (University of Arizona/Steward Observatory)
Take a close look at the blurry image above. See that gap in the cloud? That could be a planet being born some 176 light-years away from Earth. It’s a small planet, only 6 to 28 times Earth’s mass.
That’s not even the best part.
This alien world, if we can confirm it, shouldn’t be there according to conventional planet-forming theory.
The gap in the image above — taken by the Hubble Space Telescope — probably arose when a planet under construction swept through the dust and debris in its orbit, astronomers said.
That’s not much of a surprise (at first blush) given what we think we know about planet formation. You start with a cloud of debris and gas swirling around a star, then gradually the bits and pieces start colliding, sticking together and growing bigger into small rocks, bigger ones and eventually, planets or gas giant planet cores.
But there’s something puzzling astronomers this time around: this planet is a heck of a long way from its star, TW Hydrae, about twice Pluto’s distance from the sun. Given that alien systems’ age, that world shouldn’t have formed so quickly.
An illustration of TW Hydrae’s disk in comparison with that of Earth’s solar system. Credit: NASA, ESA, and A. Feild (STScI)
Astronomers believe that Jupiter took about 10 million years to form at its distance away from the sun. This planet near TW Hydrae should take 200 times longer to form because the alien world is moving slower, and has less debris to pick up.
But something must be off, because TW Hydrae‘s system is believed to be only 8 million years old.
“There has not been enough time for a planet to grow through the slow accumulation of smaller debris. Complicating the story further is that TW Hydrae is only 55 percent as massive as our sun,” NASA stated, adding it’s the first time we’ve seen a gap so far away from a low-mass star.
The lead researcher put it even more bluntly: “Typically, you need pebbles before you can have a planet. So, if there is a planet and there is no dust larger than a grain of sand farther out, that would be a huge challenge to traditional planet formation models,” stated John Debes, an astronomer at the Space Telescope Science Institute in Baltimore.
Like a raindrop forming in a cloud, a star forms in a diffuse gas cloud in deep space. As the star grows, its gravitational pull draws in dust and gas from the surrounding molecular cloud to form a swirling disk called a “protoplanetary disk.” This disk eventually further consolidates to form planets, moons, asteroids and comets. Credit: NASA/JPL-Caltech
At this point, you would suppose the astronomers are seriously investigating other theories. One alternative brought up in the press release: perhaps part of the disc collapsed due to gravitational instability. If that is the case, a planet could come to be in only a few thousand years, instead of several million.
“If we can actually confirm that there’s a planet there, we can connect its characteristics to measurements of the gap properties,” Debes stated. “That might add to planet formation theories as to how you can actually form a planet very far out.”
A rare double transit of Jupiter’s moon Ganymede (top) and Io on Jan. 3, 2013. Here, the sun is shining from the left causing shadows cast by the moons to fall onto the planet’s cloud tops. Credit: Damian Peach
There’s a trick with the “direct collapse” theory, though: astronomers believe it takes a bunch of matter that is one to two times more massive than Jupiter before a collapse can occur to form a planet.
There are also intriguing results about the gap. Chile’s Atacama Large Millimeter/submillimeter Array (ALMA) — which is designed to look at dusty regions around young stars — found that the dust grains in this system, orbiting nearby the gap, are still smaller than the size of a grain of sand.
Astronomers plan to use ALMA and the James Webb Space Telescope, which should launch in 2018, to get a better look. In the meantime, the results will be published in the June 14 edition of the Astrophysical Journal.
Neil Armstrong and David Scott in the Gemini VIII capsule, after splashdown, March 16, 1966. Credit: NASA.
So, you’ve just endured a harrowing experience where your orbiting spacecraft has gone wildly out of control. You somehow — while undergoing the incredible, vertigo-inducing G-forces of your spinning spacecraft — figure out a plan, undock your spacecraft from another spacecraft and abort your original mission.
Six and a half orbits and ten hours and 44 minutes after you’ve thunderously launched into space, you violently re-enter Earth’s atmosphere and splash down in a pitching ocean. Obviously, you have to throw up, and so does your crewmate. But there’s just one air sickness bag.
But by the time the rescue crew has arrived you’ve donned your sunglasses and look as cool as a cucumber.
That’s Neil Armstrong and Dave Scott’s experience during the Gemini 8 mission.
The different colors in this MESSENGER image of Mercury indicate the chemical, mineralogical, and physical differences between the rocks that make up the planet’s surface. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.
The MESSENGER mission has now mapped the entire surface of planet Mercury — and this is the first time this has even been done. MESSENGER is the first spacecraft to be in orbit of Mercury, and has been there since 2011, with a couple of flybys starting in 2008 as it slowly looped its way into orbit. The seven scientific instruments and radio science investigation on the spacecraft have provided an entirely new view of the planet.
This colorful view of Mercury is, of course, not what Mercury would look like to the human eye. It was created by using images from the color base map imaging campaign during MESSENGER’s primary mission. These colors enhance the chemical, mineralogical, and physical differences between the rocks that make up Mercury’s surface, allowing scientists to figure out all the different minerals that are on the planet’s surface.
The complete map of Mercury was completed and released in February of 2013, and is made of thousands of images taken by MESSENGER. The spinning video map shows Mercury as, really, we’ve not seen it before, and it is fun to watch features like large rayed craters and basins spin into view.
The MESSENGER team explained the colors:
Young crater rays, extending radially from fresh impact craters, appear light blue or white. Medium- and dark-blue areas are a geologic unit of Mercury’s crust known as the “low-reflectance material”, thought to be rich in a dark, opaque mineral. Tan areas are plains formed by eruption of highly fluid lavas. The giant Caloris basin is the large circular tan feature located just to the upper right of center of the image.
You can see an image of the other side of Mercury here, and the complete gallery of science images and mosaics here.
The Subaru Telescope. Credit: National Astronomical Observatory of Japan
Put another checkmark beside the “cold dark matter” theory. New observations by Japan’s Subaru Telescope are helping astronomers get a grip on the density of dark matter, this mysterious substance that pervades the universe.
We can’t see dark matter, which makes up an estimated 85 percent of the universe, but scientists can certainly measure its gravitational effects on galaxies, stars and other celestial residents. Particle physicists also are on the hunt for a “dark matter” particle — with some interesting results released a few weeks ago.
The latest experiment with Subaru measured 50 clusters of galaxies and found that the density of dark matter is largest in the center of these clusters, and smallest on the outskirts. These measurements are a close match to what is predicted by cold dark matter theory, scientists said.
Cold dark matter assumes that this material can’t be observed in any part of the electromagnetic spectrum, the band of light waves that ranges from high-energy X-rays to low-energy infrared heat. Also, the theory dictates that dark matter is made up of slow-moving particles that, because they collide with each other infrequently, are cold. So, the only way dark matter interacts with other particles is by gravity, scientists have said.
To check this out, Subaru peered at “gravitational lensing” in the sky — areas where the light of background objects are bent around dense, massive objects in front. Galaxy clusters are a prime example of these super-dense areas.
Several dark matter maps: one based on a sample of 50 individual galaxy clusters (left), another looking at an average galaxy cluster (center), and another based on dark matter theory (right). Red is the highest concentration of dark matter, followed by yellow, green and blue. At right, in the middle, is a map based on cold dark matter theory that comes close to the average galaxy cluster observed with the Suburu Telescope. Credit: NAOJ/ASIAA/School of Physics and Astronomy, University of Birmingham/Kavli IPMU/Astronomical Institute, Tohoku University)
“The Subaru Telescope is a fantastic instrument for gravitational lensing measurements. It allows us to measure very precisely how the dark matter in galaxy clusters distorts light from distant galaxies and gauge tiny changes in the appearance of a huge number of faint galaxies,” stated Nobuhiro Okabe, an astronomer at Academia Sinica in Taiwan who led the study.
Next, the team members could compare where the matter was most dense with that predicted by cold dark matter theory. To do that, they measured 50 of the most massive, known clusters of galaxies. Then, they measured the “concentration parameter”, or the cluster’s average density.
“They found that the density of dark matter increases from the edges to the center of the cluster, and that the concentration parameter of galaxy clusters in the near universe aligns with CDM theory,” stated the National Astronomical Observatory of Japan.
The next step, researchers stated, is to measure dark matter density in the center of the galaxy clusters. This could reveal more about how this substance behaves. Check out more about this study in Astrophysical Journal Letters.
