Earth Has Scores of Mini-Moons, Models Predict
|3:59:55 AM, Wednesday, April 04, 2012|
“(Nat. Geo.) Our moon is not alone: Scores of unseen mini-moons are now in orbit around Earth, new computer models predict.
What's more, these tiny moons occasionally plummet through our planet's atmosphere, creating brilliant fireballs, the researchers say.
The findings are based on supercomputer simulations of ten million asteroids known to fly through the Earth-moon system. The models show that objects that circle the sun in orbits similar to Earth's are likely to be captured as mini-moons.
"We accurately tracked their motion—including the gravitational tugs from the sun and all the other planets and big asteroids in the solar system—and found that 18,000 of [these asteroids] were captured and briefly went into orbit around the Earth," said study co-author Robert Jedicke, an astronomer at the University of Hawaii.
"We estimate that there are one or two washing machine-size mini-moons and about a thousand larger than a softball [orbiting Earth] at any time," he said.
The captured moons would orbit Earth in twisted, convoluted paths. In fact, the simulations show that most mini-moons hang around for less than a year before they're either spit back out to orbit the sun or end up on a collision course with Earth, Jedicke said.
"The moon perturbs the orbit of about one in a thousand, so they hit the Earth—some of the meteors that you see at night are actually mini-moons falling to Earth."
Prehistoric Double Moons?
In addition to small space rocks, the models predict that once in awhile Earth captures something even larger.
The team's estimates show that every half century an object the size of a large dump truck—about 33 feet (10 meters) across—joins our roughly 2,100-mile-wide (3,400-kilometer-wide) moon.
And even larger objects—each the size of a football field, or about 328 feet (100 meters) across—can be captured by Earth's gravity every hundred thousand years.
At that size, Jedicke speculates, the extra moons might even be visible to the naked eye.
"A hundred thousand years is about the time frame that human beings have been doing things like leaving their handprints on cave walls, so maybe in that time frame somebody once actually looked into the sky and saw a mini-moon moving across the sky," he added.
Jedicke and his team are the first to make predictions about mini-moon sizes and distribution, and it appears their predictions are fairly accurate.
The only known mini-moon was a 9.8-foot-wide (3-meter-wide) asteroid dubbed 2006 RH120, which orbited Earth less than a year before resuming its previous life orbiting the sun.
"The size and orbital properties of 2006 RH120 are perfectly consistent with our models," Jedicke said. "Had we done our study ten years ago, we could have predicted that an object like 2006 RH120 would be detected soon."
Mini-Moons Still Hard to Spot
Even with the new simulations, the researchers caution that actually seeing more mini-moons will be challenging, because the objects are relatively small and thus faint.
In addition, the gravitational effects that draw in Earth's extra moons tend to set them whipping around the planet at high speeds, making them even harder to pinpoint.
"We are currently trying to figure out how to use astronomical surveys to spot them regularly," Jedicke said.
For instance, "the largest ones could be detectable by the advanced amateur astronomer with a 50-centimeter-diameter [20-inch-diameter] telescope," he said.
"But discovering new mini-moons will require an asteroid survey that covers much of the sky in a single night and detects objects that are very faint."”
Research on Stickleback Fish Shows How Adaptation to New Environments Involves Many Genes
|3:53:27 AM, Wednesday, April 04, 2012|
“(physorg.com) A current controversy raging in evolutionary biology is whether adaptation to new environments is the result of many genes, each of relatively small effect, or just a few genes of large effect. A new study published in Molecular Ecologystrongly supports the first "many-small" hypothesis.
McGill University professor Andrew Hendry, from the Department of Biology and the Redpath Museum, and evolutionary geneticists at Basel University in Switzerland, studied how threespine stickleback fish adapted to lake and stream environments in British Columbia, Canada. The authors used cutting-edge genomic methods to test for genetic differences at thousands of positions ("loci") scattered across the stickleback genome. Very large genetic differences between lake and stream stickleback were discovered at more than a dozen of these loci, which is considerably more than expected under the alternative "few-large" hypothesis.
By examining four independently evolved lake-stream population pairs, the researchers were further able to show that increasing divergence between the populations involved genetic differences that were larger and present at more and more loci.
As these results were obtained using new high-resolution genetic methods, it is conceivable that previous perceptions of adaptation as being a genetically simple process are simply the result of a bias resulting from previous lower-resolution genomic methods.
"I suspect that as more and more studies use these methods, the tide of opinion will swerve strongly to the view that adaptation is a complex process that involves many genes spread across diverse places in the genome," says Prof. Hendry.”
Dutch 'Flying Car' Takes to the Skies
|3:44:15 AM, Wednesday, April 04, 2012|
“(physorg.com) Is it a flying car or a driving aircraft? Either way, the Personal Air and Land Vehicle, or PAL-V for short, has just proved it can handle the skies as well as the highway, both at up to 180 kilometres (112 miles) per hour, its Dutch developers said Tuesday.
The PAL-V is a gyrocopter that can fly as far as 500 kilometres (315 miles) at an altitude of up to 4,000 feet (1,200 metres).
When it lands, it tucks away its rotor-blades and turns into a road-legal three-wheeled vehicle with a range of 1,200 kilometres.
"In future, you will be able to drive from home to the airport, take off, land and then drive to your destination in one go," said Robert Dingemanse, chief executive of the company, also called PAL-V.
In development since 2008, the first commercial models of the arrow-shaped PAL-V are expected to go on sale in 2014 at 250,000-300,000 euros ($330,000-$400,000), Dingemanse told AFP.
"The successful maiden flight of the PAL-V protoype was conducted at a Dutch Air Force base last month," added the head of the company, based in Raamsdonksveer near the eastern city of Nijmegen.
"It will revolutionise the era of personal air travel," said Jacco Hoekstra, dean of the aerospace faculty at Delft Technical University, which with the Dutch National Aerospace Laboratory cooperated on the project.
"Before, air travel was mainly based on public transport," Hoekstra said. "Now it will become a lot more personal -- you will simply be able to walk out your door, drive to a small airfield and fly away."
If the PAL-V sounds like the perfect getaway vehicle from a traffic jam, there is a hitch -- it requires 165 metres of runway to take off, 30 metres to land and can only be flown from airports.
For more than a century inventors have been trying to combine cars and planes, and several companies have joined the race to make the first commercially-produced "flying car."
US-based firm Terrafugia said Monday they had successfully tested their own street-legal plane called the the "Transition."”
-- Follow the link to see it in action.
Mammoth Carcass Found in Siberia
|3:17:14 AM, Wednesday, April 04, 2012|
"(BBC) The discovery of a well-preserved juvenile mammoth suggests that ancient humans "stole" mammoths from hunting lions, scientists say.
Bernard Buigues and Professor Alice Roberts were part of the team which unwrapped the frozen mammoth, known as Yuka, after its journey from the location where tusk hunters found it in northern Siberia.
Scientists have since completed an initial assessment of Yuka.
"Its foot pads and thick strawberry-blonde hair are exquisitely preserved," noted Professor Alice Roberts.
The mammoth was filmed as part of the BBC/Discovery co-production programme Woolly Mammoth: Secrets from the Ice, which will be broadcast in the UK on Wednesday 4 April at 21:00 BST on BBC Two, and in the US on the Discovery Channel at a later date.”
-- Follow the link for video and close-ups!
Giant Tibetan Mastiff
|3:04:44 AM, Wednesday, April 04, 2012|
-- Look at this dog. Just look at it.
Amazing Glow-in-the-Dark Jellyfish Art Sculptures
|6:28:49 PM, Tuesday, April 03, 2012|
-- U.S. firm The Amazing Jellyfish (theamazingjellyfish.com) takes the bioluminescent bodies of creatures that have died of natural causes and encase them in resin, thus preserving not just their bodies, but also their incredible glow-in-the-dark properties. Do want! Beautiful!
Evidence of 'Earliest Fire Use'
|3:51:18 PM, Tuesday, April 03, 2012|
“(BBC) Scientists say they have new evidence that our ancestors were using fire as early as a million years ago.
It takes the form of ash and bone fragments recovered from Wonderwerk Cave in South Africa.
The team tells the journal PNAS that the sediments suggest frequent, controlled fires were lit on the site.
The ability to use fire is regarded as a key step in human development because it gave us access to cooked foods and new technologies.
Stone tools found at Wonderwerk Cave indicate the ancestor in question may have been Homo erectus, a species whose existence has been documented as far back as 1.8 million years ago.
Establishing precisely when humans first acquired the ability to control fire has been very difficult.
There have been several claims that the skill was in existence even earlier than at Wonderwerk.
But they have all been challenged, with sceptics arguing the fire remains from open sites could have been the result of natural blazes ignited by lightning.
In contrast, the PNAS team, which consists of scientists based at US, Israeli, German and South African institutions, says statements about the Northern Cape cave are far more secure.
If correct, the Wonderwerk discovery would push the earliest indisputable controlled use of fire back by about 300,000 years.
In their paper, the researchers describe burnt remains of grasses, brushes, leaves and even bones in the cave's sediments some 30m back from the entrance.
This makes it far less likely that what they are viewing is material from wildfires that was simply blown into the cave by wind, they argue.
The depth of the sediments also suggests fires were lit on the same spot over and over again.”
New Milky Way Photo Captures 1 Billion Stars
|4:27:45 AM, Tuesday, April 03, 2012|
“(SPACE.com) More than a billion stars blaze bright in a new photo of our Milky Way galaxy snapped by an international team of astronomers.
The new picture, which was released today (March 28), combines infrared images of the Milky Way taken during sky surveys by two different instruments, the UK Infrared Telescope in Hawaii and the VISTA telescope in Chile. The photo is part of a 10-year project that is gathering mountains of data to help guide future research, scientists said.
"This incredible image gives us a new perspective of our galaxy, and illustrates the far-reaching discoveries we can make from large sky surveys," Nick Cross, of the University of Edinburgh, said in a statement. "Having data processed, archived and published by dedicated teams leaves other scientists free to concentrate on using the data, and is a very cost-effective way to do astronomy."
Cross will present the image Thursday (March 29) at the 2012 National Astronomy Meeting in Manchester, the United Kingdom.”
-- <1%...!!! Follow the link for high resolution image!
Your Mother Was a Galaxy and You Were Born a Pearl
|3:54:25 AM, Tuesday, April 03, 2012|
-- Your mother was a galaxy
and you were born a pearl.
Olena Shmahalo, 2012
|12:23:49 AM, Tuesday, April 03, 2012|
-- Wankel engine!
NASA's New Mars Rover Will Explore Towering 'Mount Sharp'
|12:13:22 AM, Tuesday, April 03, 2012|
“A huge mountain on Mars that NASA's newest rover will explore after it touches down on the Red Planet in August now has a name: Mount Sharp.
The science team behind NASA's Mars rover Curiosity announced the new name for the mountain Wednesday (March 28). The moniker was picked to honor the late geologist Robert Sharp (1911-2004), a pioneer planetary scientist, influential teacher of many current leaders in the field and team member for NASA's first few Mars missions, researchers said.
"Bob Sharp was one of the best field geologists this country has ever had," Michael Malin of Malin Space Systems, principal investigator for two of Curiosity's 10 science instruments and a former student of Sharp's, said in a statement. "We don't really know the origins of Mount Sharp, but we have plans for how to go there and test our theories about it, and that's just how Bob would have wanted it."
The 1-ton Curiosity rover — the centerpiece of NASA's $2.5 billion Mars Science Laboratory (MSL) mission — blasted off in November and is slated to land at the Red Planet's Gale Crater on the night of Aug. 5. Its main mission is to determine if the Gale Crater area is, or ever was, capable of supporting microbial life.
Mount Sharp rises from the center of the crater, looming 3 miles (5 kilometers) above the surrounding terrain. Its layered rocks preserve a record of Mars' changing environmental conditions going back a billion years or more, providing an inviting exploration target for Curiosity.
Mars orbiters have detected minerals near Mount Sharp's base that only form in water. So some of its lower layers might tell of a lake within Gale Crater long ago, or they might indicate wind-delivered sediments later soaked by groundwater, researchers said.
Higher layers, on the other hand, may represent wind-blown dust deposited after Mars shifted from a relatively wet world to the dry and frigid planet we know today.
"Mount Sharp is the only place we can currently access on Mars where we can investigate this transition in one stratigraphic sequence," said John Grotzinger of Caltech, MSL's chief scientist. "The hope of this mission is to find evidence of a habitable environment; the promise is to get the story of an important environmental breakpoint in the deep history of the planet. This transition likely occurred billions of years ago, maybe even predating the oldest well-preserved rocks on Earth."
Mount Sharp is a gently sloping mound rather than a steep, jagged peak, so Curiosity should be able to drive pretty far up it over the course of its operational life, researchers have said.
The rover's nominal mission was designed to last about two Earth years, but it wouldn't be surprising if Curiosity kept on chugging long beyond that. NASA's Opportunity Mars rover, after all, is still going strong today more than eight years after landing, and its original mission life was pegged at 90 days.
Whatever Curiosity ends up finding would doubtless have intrigued and excited Bob Sharp, those who knew him say.
"Recognition of this remarkable scientist and leader by the naming of Mount Sharp is highly fitting, and I hope it will serve to perpetuate his legacy," said former MSL chief scientist Edward Stolper, provost at Caltech, where Sharp taught for many years.”
Dead Stars 'to Guide Spacecraft'
|6:47:26 PM, Sunday, April 01, 2012|
“(By Jonathan Amos, Science correspondent, BBC News) Spacecraft could one day navigate through the cosmos using a particular type of dead star as a kind of GPS.
German scientists are developing a technique that allows for very precise positioning anywhere in space by picking up X-ray signals from pulsars.
These dense, burnt-out stars rotate rapidly, sweeping their emission across the cosmos at rates that are so stable they rival atomic clock performance.
This timing property is perfect for interstellar navigation, says the team.
If a spacecraft carried the means to detect the pulses, it could compare their arrival times with those predicted at a reference location. This would enable the craft to determine its position to an accuracy of just five kilometres anywhere in the galaxy.
"The principle is so simple that it will definitely have applications," said Prof Werner Becker from the Max-Planck Institute for Extraterrestrial Physics in Garching.
"These pulsars are everywhere in the Universe and their flashing is so predictable that it makes such an approach really straightforward," he told BBC News.
Prof Becker has been describing his team's research here at the UK National Astronomy Meeting in Manchester.
The proposed technique is very similar to that employed in the popular Global Positioning System, which broadcasts timing signals to the user from a constellation of satellites in orbit.
But GPS only works on, or just above, the Earth so it has no use beyond our planet.
Currently, mission controllers wanting to work out the position of their spacecraft deep in the Solar System will study the differences in time radio communications take to travel to and from the satellite. It is a complex process and requires several antennas dotted across the Earth.
It is also a technique that is far from precise, and the errors increase the further away the probe moves.
For the most distant spacecraft still in operation - Nasa's Voyager satellites, which are now approaching the very edge of the Solar System, some 18 billion km away - the errors associated with their positions are on the order of several hundred km.
Even for a probe at the reasonably short separation of Mars, the positioning uncertainty can be about 10km.
It is unlikely though that navigation by pulsar beacon will find immediate use.
The telescope hardware for detecting X-rays in space has traditionally been bulky and heavy.
Engineers will need to miniaturise the technology to make a practical pulsar navigation unit.
"It becomes possible with the development of lightweight X-ray mirrors," said Prof Becker.
"These are on the way for the next generation of X-ray telescopes. Current mirrors have a 100 times more weight and would be completely unusable.
"In 15-20 years, the new mirrors will be standard and our device will be ready to be built."
The scientist believes his navigation solution will certainly find use on Solar System probes, providing autonomous navigation for interplanetary missions and perhaps for future manned ventures to Mars where high performance systems will be an absolute requirement for safety reasons.
But he also likes the idea of humanity one day pushing out across interstellar space.
"You know for GPS that if you go to another country, you have to buy the maps for your device. Well, we were joking with our students in Garching about selling maps for different galaxies for ships like Enterprise [on Star Trek]."”
Oldest Alien Planets Found—Born at Dawn of Universe
|7:22:07 PM, Saturday, March 31, 2012|
“(Nat. Geo.) Two huge planets found orbiting a star 375 light-years away are the oldest alien worlds yet discovered, scientists say.
With an estimated age of 12.8 billion years, the host star—and thus the planets—most likely formed at the dawn of the universe, less than a billion years after the big bang.
"The Milky Way itself was not completely formed yet," said study leader Johny Setiawan, who conducted the research while at the Max-Planck Institute for Astronomy in Heidelberg, Germany.
During a recent survey, Setiawan and colleagues found the signatures of the two planets orbiting the star, dubbed HIP 11952.
Based on the team's calculations, one world is almost as massive as Jupiter and completes an orbit in roughly seven days. The other planet is nearly three times Jupiter's mass and has an orbital period of nine and a half months.
It's possible the planets are much younger than they seem if the worlds formed long after their star was born—but such a scenario is unlikely, the team says.
"Usually planets form just shortly after the star formation," Setiawan said. "Second-generation planets might also form after a star has died, but this is still under debate."
Ancient Planets Defy Theory
Setiawan and colleagues found the ancient planets using a technique called radial velocity, in which astronomers watch for periodic wobbles in a star's light due to the gravitational tugs of orbiting worlds.
The discovery indicates that planet formation in the early universe was possible despite the fact that stars in existence back then were metal-poor—the astronomy term for stars lacking in elements heavier than hydrogen and helium.
In the case of HIP 11952, "its iron abundance is only about one percent that of our sun," Setiawan said.
The idea of planets springing from such a stellar makeup runs counter to a widely accepted theory called the accretion model, which says that heavy elements are needed to form planets.
Even gas giants like Saturn and Jupiter require heavy elements to take shape, the thinking goes, because they are built upon solid cores.
The accretion theory has so far been backed up by observations: Most of the planet-harboring stars discovered to date are relatively young and have moderate to high amounts of metals.
But there may be an observational bias, Setiawan said: Astronomers may think the accretion model is correct because planet hunters have been targeting mostly young, sunlike stars.
"To verify this issue, it is necessary to do a planet-search survey around [older] metal-poor stars," Setiawan said.
Clock Ticking for Oldest Worlds
Despite the newfound planets' longevity, it's unlikely the worlds will survive for another 13 billion years.
The parent star will soon transform into a red giant, Setiawan said, one of the last stages of a sunlike star's life.
During this stage, the star will swell in size and most likely engulf any nearby planets.”
Lamborghini Batman is Pulled Over in Maryland
|7:56:09 AM, Saturday, March 31, 2012|
"There really should be more Superheroes in the real world, and it seems like this unnamed wealthy philanthropist agrees. He has taken it upon himself to give some sick kids in the hospital a very special visit.
The man was first seen a few days ago, in full Batman regalia, pulled over by Montgomery County Maryland Police. He was standing next to a black convertable Lamborghini Gallardo with yellow detailing, which doubles as this generous caped crusader’s Batmobile.
The story that unfolded revealed that he was apparently pulled over because his Batmobile did not have plates on it. He allegedly had the plates in the car, but was unable to make them fit in the Lamboghini’s plateholder.
Why he was still in the Batman suit was simply for convenience. The latex outfit is difficult to get in and out of, so he wears it to his appearance and changes out of it at home.
I imagine if I was incredibly wealthy I would have a hot car too. But this guy goes one step beyond, spending his spare time putting a smile on the face of some young unfortunate soul in the hospital. He’s a true Batman if there ever was one."
Simulations Unravel Mysteries of 2009 Jupiter Impact
|6:46:34 PM, Friday, March 30, 2012|
“(PhysOrg.com) -- During July of 1994, both amateur and professional astronomers were captivated as comet Shoemaker/Levy 9 broke apart and slammed into the atmosphere of Jupiter. While these types of impacts are generally rare, a second impact event occurred fifteen years later in July of 2009. The object responsible for the 2009 impact was not directly observed, so astronomers could only make inferences about the object based on the disturbances in the Jovian atmosphere, as shown in the image above.
New research by Jarrad Pond (University of Central Florida), and a team from the University of Central Florida and University of California, Santa Cruz aims to help determine the object responsible for the 2009 impact on Jupiter. Without a direct observation of the event, the team used numerical simulations in order to better understand the object responsible for the large disturbance of the Jovian atmosphere.
Using three dimensional hydrodynamics code, the team modeled the impacts of eight simulated impactors. The team used impactors of .5 and 1km, with different densities and compositions (basalt or ice). By using the same impact angle (69 degrees) and impact velocity 61.4 km/sec), the team was able to narrow down the potential size and composition of the object responsible for the July 2009 impact…”
-- This is an unusually image heavy article for PhysOrg.com, follow the link for the rest of the article.
HOME Older Posts »