An ambulance whizzes by, and suddenly its siren drops in pitch. We are all familiar with the Doppler effect, even if we don’t know it by name. Now, scientists have found an alternative version of the phenomenon, for when sound, or light, scatters off a rotating object. The discovery could enable astronomers to measure a distant planet’s rotation, or even improve the performance of wind turbines.
Here’s how the Doppler effect works: When a noisy object is moving toward you, its sound waves bunch up, producing a higher frequency, or pitch. Conversely, as soon as the object is moving away from you, the sound waves stretch out, and the pitch lowers. The faster the object, the greater the pitch change.
The Doppler effect occurs for light as well as sound. For instance, astronomers routinely determine how fast stars and galaxies are moving away from us by measuring the extent to which their light is “stretched” into the lower frequency, red part of the spectrum. Redshifts like this were famously used in the 1920s to infer that most stars and galaxies are moving away from us and that the universe must be expanding.
Redshifts in light, and the pitch-drop of passing sirens, are examples of a linear Doppler effect. In recent decades, however, scientists have discovered that the Doppler effect also exists for objects that are rotating, the so-called orbital angular momentum (OAM) of light, and now researchers they believe they can determine how fast a planet is spinning.
Back on Earth, he adds, lasers that measure the OAM could be sent through wind farms to determine the rotation of air currents. “If you’re a windmill, you’d like to know in advance of blustery wind, so you can tether your blades.”
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Reported by JON CARTWRIGHT of ScienceNOW. This is adapted from ScienceNOW, the online daily news service of the journal Science. http://news.sciencemag.orgRead More
A Russian capsule carrying mice, lizards and other small animals returned to Earth on Sunday after spending a month in space for what scientists said was the longest experiment of its kind.
Fewer than half of the 53 mice and other rodents who blasted off on April 19 from the Baikonur Cosmodrome survived the flight, Russian news agencies reported, quoting Vladimir Sychov, deputy director of the Institute of Medical and Biological Problems and the lead researcher.
Sychov said this was to be expected and the surviving mice were sufficient to complete the study, which was designed to show the effects of weightlessness and other factors of space flight on cell structure. All 15 of the lizards survived, he said. The capsule also carried small crayfish and fish.
The capsule’s orbit reached 575 kilometers (345 miles) above Earth, according to the news agencies, which said this was far higher than the orbit of the International Space Station.
Russian state television showed the round Bion-M capsule and some of the surviving mice after it landed slightly off course but safely in a planted field near Orenburg, about 750 miles southeast of Moscow.
“This is the first time that animals have flown in space for so long on their own,” Sychov said in the television broadcast from the landing site. The last research craft to carry animals into space spent 12 days in orbit in 2007.
The mice and other animals were to be flown back to Moscow to undergo a series of tests at Sychov’s institute, which is part of the Russian Academy of Sciences.
Reported by The Associated Press from MOSCOW, Russia.
Image by TwoShortPlanks via Flickr.com.
NASA’s Cassini spacecraft has captured stunning views of a monster hurricane at Saturn’s North Pole.
The eye of the cyclone is an enormous 1,250 miles across. That’s 20 times larger than the typical eye of a hurricane here on Earth. And it’s spinning super-fast. Clouds at the outer edge of the storm are whipping around at 330 mph.
The hurricane is parked at Saturn’s North Pole and relies on water vapor to keep it churning. It’s believed to have been there for years. Cassini only recently had a chance to observe the vortex in visible light.
Scientists hope to learn more about Earth’s hurricanes by studying this whopper at Saturn.
Cassini was launched from Cape Canaveral in 1997 and arrived at Saturn in 2004.
Reported by MARCIA DUNN of the Associated Press from CAPE CANAVERAL, Fla.Read More
An international team of astronomers has found two planets whose size and position suggest they may support alien life.
The planets orbit a star about 2,000 light-years away from Earth. The star is named Kepler-62. The planets appear to be the right distance from their star for liquid water. With the chance of water, there’s also a chance for life to exist, according to research published online Thursday by the journal Science.
Compared with Earth, the planets, named Kepler-62e and Kepler-62f, are larger and receive 0.41 and 1.2 times the amount of solar radiation. The planet hunters, led by NASA’s William Borucki, say they won’t know what the planets look like or if they are in fact habitable until they can study them a while longer.
“We have found two planets in the habitable zone of another star, and they are the best planets found to date” that may support life, said Borucki, a space scientist at NASA’s Ames Research Center in Moffett Field, Calif.
One of the planets, Kepler-62f, may be a rocky celestial body with polar ice caps, Borucki said. The other, Kepler-62e, is believed to be warm and have lightning. While it’s too soon to know for sure, it may even be a water world, the first of its kind discovered, Borucki said.
“Kepler-62e probably has a very cloudy sky and is warm and humid all the way to the polar regions,” Dimitar Sasselov, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said. “Kepler-62f would be cooler, but still potentially life-friendly.”
Mission accomplished: The planets were discovered using NASA’s Kepler satellite, a spacecraft launched in 2009 with a mission to discover Earth-size and smaller celestial bodies in regions around their stars, particularly those where liquid water may exist. The spacecraft was launched in March 2009 and has found more than 2,700 planet candidates.
Kepler detects planets that cross the face of their stars, and gathers data that enables astronomers to estimate the sizes and make suggestions about composition.
The Kepler planets have 1.41 and 1.61 the radius of the Earth, according the researchers. Both planets may be solid, with either rocky or icy compositions, the scientists said.
In 2011, the Kepler mission found its first planet in the habitable zone, called Kepler-22b. That planet is larger than Earth, and orbits a sun-like star every 290 days.
Reported by EVA VON SCHAPER and ELIZABETH LOPATTO for Bloomberg News.Read More
It’s the Martian version of a spring break: Curiosity and Opportunity will take it easy this month because of the sun’s interference.
For much of April, the sun blocks the line of sight between Earth and Mars. This celestial alignment — called a Mars solar conjunction — makes it difficult for engineers to send instructions on the surface. The same problem also means that NASA can’t talk with rovers’ companion spaceships that orbit the Red Planet and help the space agency communicate with the Mars-roving robots.
Such communication blackouts occur every two years when the red planet disappears behind the sun. No new commands are sent since flares and charged particles spewing from the sun can scramble transmission signals and put spacecraft in danger.
Mission teams prepared by uploading weeks of scaled-back activities beforehand.
“They’re on their own,” said Rich Zurek, chief Mars scientist at the NASA Jet Propulsion Laboratory.
The rovers are banned from driving. Instead, they take a staycation and study their surroundings. The orbiting Mars Odyssey and Mars Reconnaissance Orbiter continue to listen for the rovers and make their own observations, but for the most part will transmit data once Mars is in view again.
Opportunity, Odyssey, Mars Reconnaissance Orbiter and the European Space Agency’s Mars Express have survived previous bouts of restricted communications. It’s the first for Curiosity, which landed last year near the Martian equator to hunt for the chemical building blocks of life.
The break continues through May 1. During that time, Curiosity can only check the weather every hour, measure radiation and look for signs of water below the desert-like surface. The limited chores are a departure for the active six-wheeler, which is used to driving, drilling and zapping its laser at rocks.
Scientists must wait until next month to drill into another rock and start the long-delayed trek to a mountain where Curiosity will search for the elusive organic molecules that are fundamental to life as we know it. The road trip was supposed to have started last year, but longer-than-expected science experiments put Curiosity behind schedule.
Odyssey, circling Mars since 2001, has experienced half a dozen blackout episodes with no problem. This time, it will try something new. There are plans to radio Earth every day even if calls are dropped, mostly to keep engineers updated on Curiosity’s health. The rover is also programmed to send daily beeps to ground controllers.
By contrast, the Mars Reconnaissance Orbiter will record and store information onboard its computers and beam it back after the hiatus. Opportunity, which parked itself in a clay-rich spot, will use the down time to study a rock and track the amount of dust in the sky.
With Mars missions on autopilot, many scientists and engineers planned to take vacation while a small crew remains on duty.
Reported by ALICIA CHANG of the Associated Press from Los Angeles, Calif. Follow her at http://twitter.com/SciWriAlicia.Read More
A Soyuz space capsule carrying an American astronaut and two Russian cosmonauts landed over the weekend on the foggy steppes of Kazakhstan, safely returning the three men to Earth after a 144-day mission to the International Space Station.
NASA’s Kevin Ford and Russians Oleg Novitsky and Yevgeny Tarelkin had been scheduled to return on Friday, but the landing was postponed by a day because of bad weather.
Live footage on NASA TV showed all three men smiling as they were helped out of the capsule and into reclining chairs to begin their acclimatization to Earth’s gravity after nearly five months in space.
A NASA TV commentator said only two of 12 search and rescue helicopters were allowed to land at the touchdown site because of heavy clouds and fog. So instead of being placed in an inflatable medical tent for checks, the astronauts were taken fairly quickly to one of the helicopters. The temperature at the time was well below freezing.
The crew was then flown to Kostanai, the staging site in Kazakhstan, where they posed for more photographs. Ford put on a traditional felt Kazakh hat and draped a matching coat over his flight suit, while holding up a matryoshka nesting doll of himself —- all souvenirs of the mission that began and ended in the Central Asian country.
The three men blasted off on Oct. 23 from the Baikonur cosmodrome, which Russia leases from Kazakhstan.
Vladimir Popovkin, the head of the Russian space agency, described the crew as “giving off good vibes, that they are a united and friendly team,” the Interfax news agency reported.
Space officials said Ford would be flown to Houston, while the Russians would return to the space training facility outside Moscow.
Their return voyage to Earth began with the Russian-made capsule undocking from the space station and beginning its slow drift away. The craft made a “flawless entry” back into the Earth’s atmosphere, descended through heavy cloud cover and landed perfectly in an upright position, the NASA commentator said.
Three other astronauts -— from Russia, the U.S. and Canada -— remain at the space station. The next three-man crew -— two Russians and an American -— is scheduled to launch from the Baikonur cosmodrome on March 29.
Reported by LYNN BERRY of the Associated Press from MOSCOW, Russia.
Now’s your chance to see the comet that passed within 100 million miles of Earth last week.
Twilight on Tuesday was supposed to provide the best photo op for the comet called Pan-STARRS. It was visible in the Northern Hemisphere just above the western horizon—right next to a crescent moon.
When viewing, temember your binoculars, but be certain not to point them at the setting sun, he warned.
Next week, the comet should be easier to spot. It will be higher in the western sky and therefore visible for longer once the sun sets. The surrounding darkness, versus twilight, will make it stand out if the sky is clear.
“Not a great comet, but still a pretty good one,” Phillips noted.
Pan-STARRS was visible for weeks from the Southern Hemisphere before popping up on the upper half of the globe in recent days.
About the comet: Although billions of year old, Pan-STARRS is making its first-ever cruise through the inner solar system. The ice ball passed within 28 million miles of the sun Sunday, its closest approach to our star and within the orbit of Mercury.
Phillips said the comet did not appear to decay during its brush with the sun, even though it encountered 10 times more intense solar rays than what we’re used to here on Earth.
Last Tuesday, Pan-STARRS made its closest approach ever of Earth.
The comet’s name is actually an acronym for the telescope in Hawaii used to discover it two years ago: the Panoramic Survey Telescope and Rapid Response System.
Astronomers believe Pan-STARRS somehow got kicked out of the Oort Cloud that is full of icy bodies beyond the orbits of Neptune and Pluto, and propelled into the inner solar system.
It will be visible in the Northern Hemisphere for weeks to come.
Have no fear: Pan-STARRS poses no threat to Earth. Neither does comet ISON, which promises to outdo Pan-STARRS.
Astronomers believe ISON will rival the moon in brightness, come November.
Space Weather: http://spaceweather.com/
Reported by MARCIA DUNN of the Associated Press from CAPE CANAVERAL, Fla.Read More
“Star Trek” fans, rejoice.
An online vote to name Pluto’s two newest, itty-bitty moons is over. And No. 1 is Vulcan, a name suggested by actor William Shatner, who played Capt. Kirk in the original “Star Trek” TV series.
Vulcan snared nearly 200,000 votes among the more than 450,000 cast during the two-week contest, which ended Monday. In second place with nearly 100,000 votes was Cerberus, the three-headed dog that guarded the gates of the underworld.
Vulcan was the Roman god of lava and smoke, and the nephew of Pluto. Vulcan was also the home planet of the pointy-eared humanoids in the “Star Trek” shows. Think Mr. Spock.
“174,062 votes and Vulcan came out on top of the voting for the naming of Pluto’s moons. Thank you to all who voted!” Shatner said in a tweet once the tally was complete.
Actor Leonard Nimoy, who portrayed the reason- and logic-based Spock, had this to say in an email to The Associated Press: “If my people were emotional they would say they are pleased.”
Not official: Don’t assume Vulcan and Cerberus are shoo-ins, though, for the two tiny moons discovered over the past two years with the Hubble Space Telescope.
The contest was conducted by SETI Institute in Mountain View, Calif., the research base for the primary moon hunter. The 10 astronomers who made the discoveries will take the voting results into account, as they come up with what they consider to be the two best names.
The International Astronomical Union has the final say, and it could be another month or two before an edict is forthcoming. Now known as P4 and P5, the moons are 15 to 20 miles across.
Other Vulcans: The leader of the teams that discovered the mini-moons, Mark Showalter said Monday he is leaning toward the popular vote.
But Showalter pointed out that asteroids thought to orbit close to the sun are called vulcanoids, and there could be some confusion if a moon of Pluto were to be named Vulcan. Vulcan, in fact, was the name given in the 19th century to a possible planet believed to orbit even closer to the sun than Mercury; no such planet ever was found.
What’s more, Showalter said in a phone interview, Vulcan is associated with lava and volcanoes, while distant Pluto is anything but hot.
As for Cerberus, an asteroid already bears that name, so maybe the Greek version, Kerberos, would suffice, said Showalter, a senior research scientist at SETI’s Carl Sagan Center.
Styx landed in No. 3 position with nearly 88,000 votes. That’s the river to the underworld.
Pluto’s three bigger moons are Charon, Nix and Hydra.
To be considered, the potential names for the two mini-moons also had to come from Greek or Roman mythology, and deal with the underworld. Twenty-one choices were available at the website http://www.plutorocks.com when voting ended Monday. Of those, nine were write-in candidates suggested by the public, including Shatner’s entry for Vulcan.
Shatner’s second choice for a name, Romulus, did not make the cut. That’s because an asteroid already has a moon by that name—along with a moon named Remus.
And forget the Disney connection.
“We love Mickey, Minnie and Goofy, too,” Showalter informed voters a few days into the voting. “However, these are not valid names for astronomical objects. Sorry.”
Altogether, 30,000 write-in candidate names poured in.
Showalter said he will keep the list handy as more moons undoubtedly pop up around Pluto once NASA’s New Horizons spacecraft arrives in 2015. It will be the first robotic flyby ever of the planetoid, or dwarf planet near the outer fringes of the solar system.
“I have learned not to underestimate Pluto,” Showalter wrote on the website. With so many good names available, “Pluto needs more moons!”
Pluto-naming contest: http://www.plutorocks.com/
Johns Hopkins University: http://pluto.jhuapl.edu/index.php
Reported by MARCIA DUNN, AP Aerospace Writer, from CAPE CANAVERAL, Fla.Read More
A meteor streaked across the sky and exploded over Russia’s Ural Mountains with the power of an atomic bomb Friday, its sonic blasts shattering countless windows and injuring nearly 1,000 people.
The spectacle deeply frightened many Russians, with some elderly women declaring that the world was coming to an end.
The meteor — estimated to be about 10 tons — entered the Earth’s atmosphere at a hypersonic speed of at least 33,000 mph and shattered into pieces about 18-32 miles above the ground, the Russian Academy of Sciences said in a statement.
Amateur video broadcast on Russian television showed an object speeding across the sky about 9:20 a.m. local time, just after sunrise, leaving a thick white contrail and an intense flash. See several versions of the blast in one video here: http://youtu.be/90Omh7_I8vI
The meteor released several kilotons of energy above the Chelyabinsk region, the science academy said. The shock wave blew in an estimated more than 1 million square feet of glass, according to city officials.
“There was panic. People had no idea what was happening,” said Sergey Hametov, a resident of Chelyabinsk, a city of 1 million about 930 miles east of Moscow.
“We saw a big burst of light, then went outside to see what it was and we heard a really loud, thundering sound,” he told The Associated Press by telephone.
Another heavenly object: The meteor hit less than a day before Asteroid 2012DA14 is to make the closest recorded pass of an asteroid to the Earth — about 17,150 miles. But the European Space Agency in a tweet said its experts had determined there was no connection — just cosmic coincidence.
Meteors typically cause sizeable sonic booms when they enter the atmosphere because they are traveling so much faster than the speed of sound.
At school: Lessons had just started at Chelyabinsk schools when the meteor exploded, and officials said 204 schoolchildren were among those injured.
Yekaterina Melikhova, a high school student whose nose was bloody and whose upper lip was covered with a bandage, said she was in her geography class when they saw a bright light outside.
“After the flash, nothing happened for about three minutes. Then we rushed outdoors. I was not alone, I was there with Katya. The door was made of glass, a shock wave made it hit us,” she said.
Some fragments of the meteor fell in a reservoir outside the town of Chebarkul, the regional governor’s office said, according to the ITAR-Tass.
A 20-foot-wide crater was found in the same area, which could come from space fragments striking the ground, the news agency cited military spokesman Yaroslavl Roshchupkin as saying.
Small pieces of space debris — usually parts of comets or asteroids — that are on a collision course with the Earth are called meteoroids. They become meteors when they enter the Earth’s atmosphere. Most meteors burn up in the atmosphere, but if they survive the frictional heating and strike the surface of the Earth they are called meteorites.
Similar hit in 1908: The site of Friday’s spectacular show is about 3,000 miles west of Tunguska, which 1908 was the site of the largest recorded explosion of a space object plunging to Earth. That blast, attributed to a comet or asteroid fragment, is generally estimated to have been about 10 megatons; it leveled some 80 million trees.
Scientists believe that a far larger meteorite strike on what today is Mexico’s Yucatan Peninsula may have been responsible for the extinction of the dinosaurs about 66 million years ago. According to that theory, the impact would have thrown up vast amounts of dust that blanketed the sky for decades and altered the climate on Earth
Jokes: Other quickly took to the Internet and put what they said were meteorite fragments up for sale.
The Russian-language hashtags for the meteorite shot into Twitter’s top trends, and the country’s lively blogosphere quickly reacted with black humor.
One of the most popular jokes was that the meteorite was supposed to fall Dec. 21 last year — when many believed the Mayan calendar predicted the end of the world — but was delivered late by Russia’s notoriously inefficient postal service.
Reported by JIM HEINTZ and VLADIMIR ISACHENKOV of the Associated Press from MOSCOW, Russia. Max Seddon contributed to this story.
Want to name Pluto’s two tiniest moons? Then you’ll need to dig deep into mythology.
Astronomers announced a contest Monday to name the two itty-bitty moons of Pluto discovered over the past two years.
Pluto is the Roman equivalent of the Greek’s Hades, lord of the underworld, and its three bigger moons have related mythological names: Charon, the ferryman of Hades; Nix for the night goddess; and the multi-headed monster Hydra.
The two unnamed moons — no more than 15 to 20 miles across — need similarly shady references. Right now, they go by the bland titles of P4 and P5.
Online voting will last two weeks, ending Feb. 25. Twelve choices are available at the website http://www.pluto rocks.com.
The choices are:
- Acheron – One of the five rivers of the underworld, symbolizing pain.
- Alecto – One of the furies, hideous snake-haired monsters who were servants of Hades. It was the job of Alecto to punish mortals for their crimes of anger.
- Cerberus (or Kerberos) – The three-headed dog who guards the gates to the underworld, preventing the the dead from escaping.
- Erebus – A primordial god and the personification of darkness. With Nyx, he fathered many children including Hypnos and Styx.
- Eurydice – The wife of Orpheus, for whom he entered the underworld. During their journey home, Orpheus violated his agreement with Persephone not to look back, and Eurydice was lost forever.
- Heracles (or Hercules) – The heroic demigod who slew the Hydra, entered the underworld and who also carried Cerberus back. He is one of very few who ever returned from the underworld.
- Hypnos – A son of Nyx and the personification of sleep.
- Lethe — One of the five rivers of the underworld, symbolizing oblivion. It flows through the cave of Hypnos and merges with the river Styx.
- Obol (or Obolus) – The coin paid to Charon in order to obtain passage across the river Styx.
- Orpheus (or Orfeus) – A gifted musician who entered the underworld to retrieve his wife Eurydice. He charmed Hades and Persephone with his music, and became the only mortal ever to return from the underworld.
- Persephone (or Proserpina) – A goddess kidnapped by Hades to become the queen of the underworld. She is the symbolizes vegetation and rebirth.
- Styx – The river that separates Earth from the underworld. This name also refers to the goddess of the river Styx, daughter of Nyx and Erebus.
“The Greeks were great storytellers, and they have given us a colorful cast of characters to work with,” said Mark Showalter, senior research scientist at SETI Institute’s Carl Sagan Center in Mountain View, Calif.
Write-in name suggestions are welcomed, but they need to come from Greek or Roman mythology and deal with the underworld.
The name for Pluto came from a little English girl. Pluto’s discoverer, Clyde Tombaugh, liked that the first two letters were the same as the initials of late American astronomer Percival Lowell. Tombaugh discovered Pluto in 1930 using the Lowell Observatory in Flagstaff, Ariz.
Reported by MARCIA DUNN of the Associated Press from CAPE CANAVERAL, Fla.
Pluto-naming contest: http://www.plutorocks.com/
Johns Hopkins University: http://pluto.jhuapl.edu/index.phpRead More
A 150-foot-wide asteroid will come remarkably close to Earth this week, even closer than high-flying communication and weather satellites. It will be the nearest known flyby for an object of this size.
But don’t worry. Scientists promise the megarock will be at least 17,100 miles away when it zips past on Friday.
“No Earth impact is possible,” Donald Yeomans, manager of NASA’s Near-Earth Object program at Jet Propulsion Laboratory in Pasadena, Calif., said Thursday.
Even the chance of an asteroid-satellite run-in is extremely remote, Yeomans and other scientists noted. A few hundred satellites orbit at 22,300 miles, higher than the asteroid’s path, although operators are being warned about the incoming object for tracking purposes.
“No one has raised a red flag, nor will they,” Yeomans told reporters. “I certainly don’t anticipate any problems whatsoever.”
Yet Asteroid 2012 DA14, as it’s known for its discovery date, still could pack a wallop.
If it impacted Earth — which it won’t, scientists were quick to add last week — it would release the energy equivalent of 2.4 million tons of TNT and wipe out 750 square miles. That’s what happened in Siberia in 1908, when forest land around the Tunguska River was flattened by a slightly smaller asteroid that exploded about five miles above ground.
The likelihood of something this size striking Earth is once in every 1,200 years. A close, harmless encounter like this is thought to occur every 40 years.
The bulk of the solar system’s asteroids are located between the orbits of Mars and Jupiter, and remain stable there for billions of years. Some occasionally pop out, though, into Earth’s neighborhood
The closest approach of this one will occur next Friday afternoon, Eastern time, over Indonesia.
There won’t be much of a show. The asteroid will zip by at 17,400 mph. That’s roughly eight times faster than a bullet from a high-speed rifle.
Hard to see: The asteroid will be invisible to the naked eye and even with binoculars and telescopes will appear as a small point of light. The prime viewing locations will be in Asia, Australia and eastern Europe.
Observers in the U.S. can pretty much forget it. Astronomers using NASA’s deep-space antenna in California’s Mojave Desert will have to wait eight hours after the closest approach to capture radar images.
Scientists welcome whatever pictures they get. The asteroid offers a unique opportunity to observe something this big and close, and any new knowledge will help if and when another killer asteroid is headed Earth’s way.
More out there: The close approach also highlights the need to keep track of what’s out there, if for no other reason than to protect the planet.
NASA’s current count of near-Earth objects: just short of 10,000, the result of a concentrated effort for the past 15 years. That’s thought to represent less than 10 percent of the objects out there.
No one has ruled out a serious Earth impact, although the probability is said to be extremely low.
“We don’t have all the money in the world to do this kind of work” for tracking and potentially deflecting asteroids, said Lindley Johnson, an executive with the Near-Earth Object observations program in Washington.
Indeed, when asked about NASA’s plans to send astronauts to an asteroid in the decades ahead, as outlined a few years ago by President Barack Obama, Johnson said the space agency is looking at a number of options for human explorations.
One of the more immediate steps, planned for 2016, is the launch of a spacecraft to fly to a much bigger asteroid, collect samples and return them to Earth in 2023.
The asteroid: As for Asteroid 2012 DA14 — discovered last year by astronomers in Spain — scientists suspect it’s made of silicate rock, but aren’t sure. Its shape and precise size also are mysteries.
What they do know with certainty:
“This object’s orbit is so well known that there’s no chance of a collision,” Yeomans repeated during Thursday’s news conference.
Its close approach, in fact, will alter its orbit around the sun in such a way as to keep it out of Earth’s neighborhood, at least in the foreseeable future, Yeomans said.
Johnson anticipates no “sky is falling thing” related to Friday’s flyby.
He and other scientists urged journalists to keep the close encounter in perspective.
“Space rocks hit the Earth’s atmosphere on a daily basis. Basketball-size objects come in daily. Volkswagen-size objects come in every couple of weeks,” Yeomans said.
The grand total of stuff hitting the atmosphere every day? “About 100 tons,” according to Yeoman, though most of it arrives harmlessly as sand-sized particles.
University of Arizona: http://osiris-rex.lpl.arizona.edu/Read More
Earth-like worlds may be closer and more plentiful than anyone imagined.
Astronomers reported Wednesday that the nearest Earth-like planet may be just 13 light-years away—or some 77 trillion miles. That planet hasn’t been found yet, but should be there based on the team’s study of red dwarf stars.
Galactically speaking, that’s right next door.
If our Milky Way galaxy were shrunk to the size of the United States, the distance between Earth and its closest Earth-like neighbor would be the span of New York’s Central Park, said Harvard University graduate student Courtney Dressing, the study’s lead author.
“The nearest Earth-like planet is simply a stroll across the park away,” she said at a news conference in Cambridge, Mass.
Small, cool red dwarfs are the most common stars in our galaxy, numbering at least 75 billion.
The Harvard-Smithsonian Center for Astrophysics team estimates 6 percent of red dwarf stars have Earth-like planets. To qualify, the planet must be roughly the size of Earth and get as much light from its star, as Earth does from the sun.
This high rate of occurrence should simplify the search for extraterrestrial life.
As the report’s co-author, David Charbonneau, noted, he’s an astronomer, but hopes to become a biologist if that search succeeds.
These planetary candidates are quite different than Earth because of the differences between their red dwarf stars and the sun, Charbonneau told reporters.
Because the red dwarfs are so much smaller, potentially habitable planets would need to orbit much closer than the Earth does to the sun. They likely would be rocky, the astronomers said, but different types of atmospheres could lead to different types of life.
Red dwarf stars also can be old—far older than our sun—which means their planets could be much older than Earth and their potential life forms much more evolved.
Our solar system is 4.5 billion years old, for instance, while some red dwarf stars are 12 billion years old. One of these target planets could be 12 billion years old as well, the scientists said.
Future spacecraft should be able to locate these planets and provide environmental clues.
Reported by MARCIA DUNN of the Associated Press from CAPE CANAVERAL, Fla.Read More