Showing posts with label after. Show all posts
Showing posts with label after. Show all posts

Friday, 2 December 2011

Russia's Phobos-Grunt Mission to Mars is Stuck in Earth Orbit After Engines Fail to Fire

Russia's Phobos-Grunt Mission to Mars is Stuck in Earth Orbit After Engines Fail to Fire | Popular Science@import "/files/css/a1c433465f8fe485195cb11d70c36108.css";@import "/files/css/33f6b7ecb4513ed2fe6c670880a27187.css"; home Login/Register Newsletter Subscribe RSS GadgetsComputersCamerasSmartphonesVideo GamesCarsConceptsHybridsElectric CarsScienceFuture of the EnvironmentEnergyHealthTechnologyMilitaryAviationSpaceRobotsEngineeringDIYProjectsHacksToolsAuto DIYMore From Our Partner: Toolmonger GalleriesVideosColumnsThe GrouseSex FilesGreen Dream Innovation ChallengesHow It WorksFeatures Tweet Digg Russia's Phobos-Grunt Mission to Mars is Stuck in Earth Orbit After Engines Fail to Fire Engineers have three days to save the craft before its batteries run out By Clay Dillow Posted 11.09.2011 at 10:45 am 20 Comments
Phobos-Grunt and Upper Stage A model of the Phobos-Grunt probe with its upper state MKonair on Flickr

A day after the successful launch of the Phobos-Grunt probe from Baikonur Cosmodrome in Kazakhstan, Russian mission handlers are already scrambling to save their spacecraft from the fate that has befallen so many Russian Mars missions. Phobos-Grunt found orbit yesterday but then failed to fire the engines that would put it on a path for the Martian moon Phobos. The probe is now stuck in Earth orbit, and engineers have three days to fix the problem before the batteries run out.

Problems for the multi-year mission arose almost immediately after the spacecraft was dropped into elliptical orbit eleven minutes after launching. The orientation system was supposed to use the stars to turn itself toward Phobos, then initiate two firings of the huge cruise stage attached to the spacecraft that would first lift it from orbit and then set it on a path toward Phobos.

None of this happened.

Related ArticlesRussian Probe Launches Today, Heading to Mars' Runt MoonRussian Progress Cargo Spacecraft Crashes in Eastern Russia After Failing to Find OrbitKremlin's Favorite Innovator Pushes Dubious Science, Russian Researchers SayTagsTechnology, Clay Dillow, Mars, phobos, phobos-grunt, roscosmos, russian space agency, Space, space scienceHowever, all is not yet lost. “I would not say it’s a failure,” Roscosmos chief Vladimir Popovkin told the media. “It’s a non-standard situation, but it is a working situation.”

Engineers are now racing against the clock the get Phobos-Grunt back online. If it’s a software glitch causing the problem, new commands can be uploaded and it’s likely the mission could be saved. But if it’s a hardware problem, the entire mission might be doomed before it gets out of Earth orbit.

Phobos-Grunt isn’t just Russia’s most ambitious space project in years, but the largest interplanetary science mission ever devised (after Cassini-Huygens) at more than 14 tons. The spacecraft is also carrying Yinghuo-1, China’s first Mars satellite. If lost, Phobos-Grunt would be something like the 16th Mars-related mission sent by Russia to the Red Planet since the ‘60s. None of the previous have completed their mission objectives.

[BBC]

Previous Article: Video: A Steerable Remote 'Telexistence' Robot that Transmits Sight, Sound, and Touch to the OperatorNext Article: New Super-Black Material Absorbs 99 Percent of All Light That Dares to Strike It 20 Comments Link to this comment scientific anomaly 11/09/11 at 10:58 am

told you so

-Knock knock
-Who's there?
-The Doctor.
-Doctor Who?
-Yes

Link to this comment lawsonrw 11/09/11 at 11:10 am

And these are the guys we're relying on to get our astronauts and equipment to space? Give me a break!

Link to this comment pheonix1012 11/09/11 at 11:17 am

Damn! Now we'll never get those microbes onto Phobos. Roscosmos has really gotta step it's game up. We're relying on them to send astronauts into LEO. If they got software and hardware issues this will spell disaster for future manned flights.

Link to this comment shutterpod 11/09/11 at 11:26 am

Lets hope they get it working...

Link to this comment Delkomatic 11/09/11 at 11:34 am

haha
Only thing good about Russia is the women

Link to this comment pheonix1012 11/09/11 at 11:36 am

I don't care how many unmanned vehicles they bust up. The one thing I don't want to wake up to is the news of several people dying on another launch or re-entry attempt.

Spaceflight advocacy is already at an all time low. The death of a few more astronauts will be just enough to kill support of human spaceflight all together.

Roscosmos needs to get their s### right if we're going to trust them with the lives of scientists, engineers, and technicians bound for space (this includes their own countrymen).

Link to this comment pheonix1012 11/09/11 at 11:37 am

@Delkomatic

I've heard Ukraine is where it's at.

Link to this comment pioneer10 11/09/11 at 11:39 am

There was a time I was only too happy to hear of yet another Russian Mars Mission failure. Mars96 was the first time I instead felt sympathy. Now, I feel as anxious as any of them to hear word that the mission, or any part of it can continue successfully. C'mon comrades, you can do it!

Link to this comment JediMindset 11/09/11 at 12:19 pm

lol im sorry i just had to laugh.

@Delkomatic, pheonix1012

yep you gotta love east European women!!

_________________
The people of the world only divide into two kinds, One sort with brains who hold no religion, The other with religion and no brain.

- Abu-al-Ala al-Marri

Link to this comment pheonix1012 11/09/11 at 12:32 pm

@JediMindset

Actually, I'm more into middle-eastern and latin women. Thing of beauty.

Link to this comment Grunt 11/09/11 at 1:07 pm

I like to see the next USA probe that lands on Mars or even orbit Mars to possess a high power laser. Each time Russia shots off another probe to Mars, we power up the old laser and zap into crash landing. They are so used to messing up their probes; they never suspect it was us, lol.
Ooops, I have said to much.

Link to this comment rg-5 11/09/11 at 1:32 pm

Go suck your Bawls JediMindSh'I't

Link to this comment Aldrons Last Hope 11/09/11 at 2:33 pm

@Grunt, you probably just revealed the plan for space dominance D'oh!!

I was worried that it would get lost on the way to Mars, kind of a non-issue now :-/

Link to this comment aarontco 11/09/11 at 3:09 pm

For the sake of science, I hope they grunt this little guy out of earth orbit and onto phobos. I have been envious for some time about the prospect of the Russians being the first nation to return materials from a martian moon. It should have been NASA, but our program can't do everything, and often has its priorities completely mixed up.

A phobos landing is another step toward becoming an interplanetary species, so let's hope they get lucky and succeed.

Link to this comment gizmowiz 11/09/11 at 5:45 pm

It's a shame mankind waste money on space when were not involved enough yet to dare show our faces to other civilizations anywhere. Mankind has a long way to go back here on planet earth which is where we need to focus our energies. NASA should be focusing on deep sea ventures instead.

Link to this comment JediMindset 11/09/11 at 6:50 pm

@pheonix1012
yep also Asian and African. come to think about it, i love them all!!

@rg-5
why do you say such mean things?

_________________
The people of the world only divide into two kinds, One sort with brains who hold no religion, The other with religion and no brain.

- Abu-al-Ala al-Marri

Link to this comment Robot 11/09/11 at 7:03 pm

Probes are wonderful. ;)

Link to this comment prime2011 11/09/11 at 9:36 pm

Eventually we will develop AI to be able to resolve much of these issues by itself, saving us poor humans the headache of going through reams of code trying to figure out where the glitch is. A AI could intercept a issue and attempt to make adjustments on the fly to correct issues, even re-programming aspects of itself.

The AI I am talking about is proper AI, like perhaps that on 2001 space odyssey but without the talking and irrational behaviour :)

Link to this comment Raynre 11/09/11 at 10:54 pm

Isn't this something like the third failed Russian launch in as many months?

And we rely on them to get our astronauts into orbit. So comforting...

Link to this comment lyls14 11/10/11 at 12:04 am

Crazy.Stupid.Love.720p.BluRay.x264-REFiNED
MEGAUPLOAD LINKS
http://www.lovetoshopping.org

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November 2011: Data Is Power

This month, we examine all the ways information is driving our future, from dating to crime to how we see the world.

Plus: turning your smartphone into a wallet, BMW's electric cars, and a space heater with no fan.

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Popular on Popsci Most Viewed TechnologyGallery: A History of Data TheftGallery: A Glass Astronomical Database Goes Digital Gallery: When the Best Tool Is an AnimalArchive Gallery: The Power of Data Most Emailed TechnologyWhen the Best Tool for the Job Is an AnimalGallery: When the Best Tool Is an AnimalVideo: Kinect Provides the Seeing Eye in a Robotic Guide Dog for the BlindNew Super-Black Material Absorbs 99 Percent of All Light That Dares to Strike ItRussia's Phobos-Grunt Mission to Mars is Stuck in Earth Orbit After Engines Fail to FireTo Create the Perfect Machine, Soldiers Build a Robot Out of RobotsVideo: A Steerable Remote 'Telexistence' Robot that Transmits Sight, Sound, and Touch to the OperatorHome 3-D Viewing Equipment Is Getting Smaller and Smaller and SmallerBell Labs's Nethead Makes Telepresence Robots Affordable for AllDoctor Offers Laser Treatment to Permanently Make Brown Eyes Blue Most Commented TechnologyTo Find Alien Cities, Look for City Lights on Distant PlanetsA Texas Sheriff's Department is Launching an Unmanned Helodrone that Could Carry WeaponsThe Unsplittable BitDoctor Offers Laser Treatment to Permanently Make Brown Eyes BlueNew Super-Black Material Absorbs 99 Percent of All Light That Dares to Strike ItThe Glory of Big DataRussia's Phobos-Grunt Mission to Mars is Stuck in Earth Orbit After Engines Fail to FireTo Keep a Steady Stream of Satellites Going Up, DARPA Wants to Launch Them from AirplanesGround-Based Laser Cannon to Turn Space Debris into Self-Powered Flaming De-Orbiting RocketsThe Greatest Data Thefts in History circ-top-header.gif circ-cover.gif Name Address 1   City State STATE Alabama Alaska Arizona Arkansas California Colorado Connecticut Delaware DC Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York N. Carolina N. Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island S. Carolina S. Dakota Tennessee Texas Utah Vermont Virginia Washington W. Virginia Wisconsin Wyoming Zip Code Email Today on PopSci.com The Ten Most Amazing Databases in the World581101211Can Technology Save the Military From a Data Deluge?582371213See The Data-Centric Universe, Then and Now582431214The Santa Cruz Experiment: Can a City's Crime Be Predicted and Prevented?576731215The Glory of Big Data577221216The Most Amazing Science Images of the Week, October 24-28580521217Archive Gallery: The Telephone580511218Gallery: Last Night's Auroras as They Appeared from Across the Hemisphere579731219iPhone 4S Review: Apple's Restraint5798512110Inside the DIY Weapons Workshop of the Libyan Rebels5792612111Archive Gallery: Classic Thrill Rides and Carnival Attractions5776612112 Footer Menu Subscribe to the Print EditionSubscribe to the Digital EditionRenew SubscriptionCustomer ServiceSite MapAbout UsContact UsAdvertisingPrivacy PolicyTerms of UseAbuseRSS FeedsPS Showcase

 

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Wednesday, 5 October 2011

Venus weather not boring after all, scientists discover

ScienceDaily (Sep. 27, 2011) — At first glance, a weather forecaster for Venus would have either a really easy or a really boring job, depending on your point of view. The climate on Venus is widely known to be unpleasant -- at the surface, the planet roasts at more than 800 degrees Fahrenheit under a suffocating blanket of sulfuric acid clouds and a crushing atmosphere more than 90 times the pressure of Earth's. Intrepid future explorers should abandon any hope for better days, however, because it won't change much.

"Any variability in the weather on Venus is noteworthy, because the planet has so many features to keep atmospheric conditions the same," says Dr. Tim Livengood, a researcher with the National Center for Earth and Space Science Education, Capitol Heights, Md., and now with the University of Maryland, College Park, Md.

"Earth has seasons because its rotation axis is tilted by about 23 degrees, which changes the intensity of sunlight and the length of the day in each hemisphere throughout the year. However, Venus has been tilted so much, it's almost completely upside down, leaving it with a net tilt of less than three degrees from the sun, so the seasonal effect is negligible," explains Livengood, who is stationed at NASA's Goddard Space Flight Center in Greenbelt, Md. "Also, its orbit is even more circular than Earth's, which prevents it from getting significantly hotter or cooler by moving closer to or further away from the sun. And while you might expect things to cool down at night -- especially since Venus rotates so slowly that its night lasts almost two Earth months -- the thick atmosphere and sulfuric acid clouds act like a blanket while winds move heat around, keeping temperatures pretty even. Finally, almost all the planet's water has escaped to space, so you don't get any storms or precipitation like on Earth where water evaporates and condenses as clouds."

However, higher up, the weather gets more interesting, according to a new study of old data by NASA and international scientists. The team detected strange things going on in data from telescopic observations of Venus in infrared light at about 68 miles (110 kilometers) above the planet's surface, in cold, clear air above the acid clouds, in two layers called the mesosphere and the thermosphere.

"Although the air over the polar regions in these upper atmospheric layers on Venus was colder than the air over the equator in most measurements, occasionally it appeared to be warmer," said Dr. Theodor Kostiuk of NASA Goddard. "In Earth's atmosphere, a circulation pattern called a 'Hadley cell' occurs when warm air rises over the equator and flows toward the poles, where it cools and sinks. Since the atmosphere is denser closer to the surface, the descending air gets compressed and warms the upper atmosphere over Earth's poles. We saw the opposite on Venus. In addition, although the surface temperature is fairly even, we've seen substantial changes -- up to 54 degrees Fahrenheit (about 30 K change) -- within a few Earth days in the mesosphere -- thermosphere layers over low latitudes on Venus. The poles appeared to be more stable, but we still saw changes up to 27 degrees Fahrenheit (about 15 K change)."

Kostiuk and Livengood are co-authors of a paper about these observations that appeared July 23 in the online edition of the journal Icarus.

"The mesosphere and thermosphere of Venus are dynamically active," said lead author Dr. Guido Sonnabend of the University of Cologne, Germany. "Wind patterns resulting from solar heating and east to west zonal winds compete, possibly resulting in altered local temperatures and their variability over time."

This upper atmospheric variability could have many possible causes, according to the team. Turbulence from global air currents at different altitudes flowing at more than 200 miles per hour in opposite directions could exchange hot air from below with cold air from above to force changes in the upper atmosphere. Also, giant vortexes swirl around each pole. They, too, could generate turbulence and change the pressure, causing the temperature to vary.

Since the atmospheric layers the team observed are above the cloud blanket, they may be affected by changes in sunlight intensity as day transitions to night, or as latitude increases toward the poles. These layers are high enough that they could even be affected by solar activity (the solar cycle), such as solar explosions called flares and eruptions of solar material called coronal mass ejections.

Changes were seen over periods spanning days, to weeks, to a decade. Temperatures measured in 1990-91 are warmer than in 2009. Measurements obtained in 2007 using Goddard's Heterodyne Instrument for Planetary Wind and Composition (HIPWAC) observed warmer temperature in the equatorial region than in 2009. Having seen that the atmosphere can change, a lot more observations are needed to determine how so many phenomena can affect Venus' upper atmosphere over different intervals, according to the team.

"In addition to all these changes, we saw warmer temperatures than those predicted for this altitude by the leading accepted model, the Venus International Reference Atmosphere model," said Kostiuk. "This tells us that we have lots of work to do updating our upper atmospheric circulation model for Venus."

Although Venus is often referred to as Earth's twin, since they are almost the same size, it ended up with a climate very different from Earth. A deeper understanding of Venus' atmosphere will let researchers compare it to the evolution of Earth's atmosphere, giving insight as to why Earth now teems with life while Venus suffered a hellish fate.

The team measured temperature and wind speeds in Venus' upper atmosphere by observing an infrared glow emitted by carbon dioxide (CO2) molecules when they were energized by light from the sun. Infrared light is invisible to the human eye and is perceived by us as heat, but it can be detected by special instruments. In the research, it appeared as a line on a graph from a spectrometer, an instrument that separates light into its component colors, each of which corresponds to a specific frequency. The width of the line revealed the temperature, while shifts in its frequency gave the wind speed.

The researchers compared observations from 1990 and 1991 using Goddard's Infrared Heterodyne Spectrometer instrument at NASA's Infrared Telescope Facility on Mauna Kea, Hawaii, to observations from 2009 using the Cologne Tunable Heterodyne Infrared Spectrometer instrument at the National Optical Astronomy Observatory's McMath Telescope at Kitt Peak, Ariz.

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Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Goddard Space Flight Center.

Journal Reference:

Guido Sonnabend, Peter Krötz, Frank Schmülling, Theodor Kostiuk, Jeff Goldstein, Manuela Sornig, Dušan Stupar, Timothy Livengood, Tilak Hewagama, Kelly Fast, Arnaud Mahieux. Thermospheric/mesospheric temperatures on Venus: Results from ground-based high-resolution spectroscopy of CO2 in 1990/1991 and comparison to results from 2009 and between other techniques. Icarus, 2011; DOI: 10.1016/j.icarus.2011.07.015

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.


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Sunday, 14 August 2011

Escaping gravity's clutches: Information could escape from black holes after all, study suggests

ScienceDaily (Aug. 11, 2011) — New research by scientists at the University of York gives a fresh perspective on the physics of black holes. Black holes are objects in space that are so massive and compact they were described by Einstein as "bending" space. Conventional thinking asserts that black holes swallow everything that gets too close and that nothing can escape, but the study by Prof. Samuel Braunstein and Dr. Manas Patra suggests that information could escape from black holes after all.

The implications could be revolutionary, suggesting that gravity may not be a fundamental force of nature.

Prof. Braunstein says: "Our results didn't need the details of a black hole's curved space geometry. That lends support to recent proposals that space, time and even gravity itself may be emergent properties within a deeper theory. Our work subtly changes those proposals, by identifying quantum information theory as the likely candidate for the source of an emergent theory of gravity."

But quantum mechanics is the theory of light and atoms, and many physicists are skeptical that it could be used to explain the slow evaporation of black holes without incorporating the effects of gravity.

The research, which appears in the latest issue of Physical Review Letters, uses the basic tenets of quantum mechanics to give a new description of information leaking from a black hole.

Prof. Braunstein says: "Our results actually extend the predictions made by well-established techniques that rely on a detailed knowledge of space time and black hole geometry."

Dr. Patra adds: "We cannot claim to have proven that escape from a black hole is truly possible, but that is the most straight-forward interpretation of our results. Indeed, our results suggest that quantum information theory will play a key role in a future theory combining quantum mechanics and gravity."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of York.

Journal Reference:

Samuel Braunstein, Manas Patra. Black Hole Evaporation Rates without Spacetime. Physical Review Letters, 2011; 107 (7) DOI: 10.1103/PhysRevLett.107.071302

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.


View the original article here

Sunday, 26 June 2011

'Dead' galaxies aren't so dead after all

ScienceDaily (June 1, 2011) — University of Michigan astronomers examined old galaxies and were surprised to discover that they are still making new stars. The results provide insights into how galaxies evolve with time. U-M research fellow Alyson Ford and astronomy professor Joel Bregman presented their findings May 31 at a meeting of the Canadian Astronomical Society in London, Ontario.

Using the Wide Field Camera 3 on the Hubble Space Telescope, they saw individual young stars and star clusters in four galaxies that are about 40 million light years away. One light year is about 5.9 trillion miles.

"Scientists thought these were dead galaxies that had finished making stars a long time ago," Ford said. "But we've shown that they are still alive and are forming stars at a fairly low level."

Galaxies generally come in two types: spiral galaxies, like our own Milky Way, and elliptical galaxies. The stars in spiral galaxies lie in a disk that also contains cold, dense gas, from which new stars are regularly formed at a rate of about one sun per year.

Stars in elliptical galaxies, on the other hand, are nearly all billions of years old. These galaxies contain stars that orbit every which way, like bees around a beehive. Ellipticals have little, if any, cold gas, and no star formation was known.

"Astronomers previously studied star formation by looking at all of the light from an elliptical galaxy at once, because we usually can't see individual stars," Ford said. "Our trick is to make sensitive ultraviolet images with the Hubble Space Telescope, which allows us to see individual stars."

The technique enabled the astronomers to observe star formation, even if it is as little as one sun every 100,000 years.

Ford and Bregman are working to understand the stellar birth rate and likelihood of stars forming in groups within ellipticals. In the Milky Way, stars usually form in associations containing from tens to 100,000 stars. In elliptical galaxies, conditions are different because there is no disk of cold material to form stars.

"We were confused by some of the colors of objects in our images until we realized that they must be star clusters, so most of the star formation happens in associations," Ford said.

The team's breakthrough came when they observed Messier 105, a normal elliptical galaxy that is 34 million light years away, in the constellation Leo. Though there had been no previous indication of star formation in Messier 105, Ford and Bregman saw a few bright, very blue stars, resembling a single star 10 to 20 times the mass of the sun.

They also saw objects that aren't blue enough to be single stars, but instead are clusters of many stars. When accounting for these clusters, stars are forming in Messier 105 at an average rate of one sun every 10,000 years, Ford and Bregman concluded. "This is not just a burst of star formation but a continuous process," Ford said.

These findings raise new mysteries, such as the origin of the gas that forms the stars.

"We're at the beginning of a new line of research, which is very exciting, but at times confusing," Bregman said. "We hope to follow up this discovery with new observations that will really give us insight into the process of star formation in these 'dead' galaxies."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Michigan.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.


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Saturday, 28 May 2011

Doppler effect found even at molecular level -- 169 years after its discovery

ScienceDaily (May 11, 2011) — Whether they know it or not, anyone who's ever gotten a speeding ticket after zooming by a radar gun has experienced the Doppler effect -- a measurable shift in the frequency of radiation based on the motion of an object, which in this case is your car doing 45 miles an hour in a 30-mph zone.

But for the first time, scientists have experimentally shown a different version of the Doppler effect at a much, much smaller level -- the rotation of an individual molecule. Prior to this such an effect had been theorized, but it took a complex experiment with a synchrotron to prove it's for real.

"Some of us thought of this some time ago, but it's very difficult to show experimentally," said T. Darrah Thomas, a professor emeritus of chemistry at Oregon State University and part of an international research team that just announced its findings in Physical Review Letters, a professional journal.

Most illustrations of the Doppler effect are called "translational," meaning the change in frequency of light or sound when one object moves away from the other in a straight line, like a car passing a radar gun. The basic concept has been understood since an Austrian physicist named Christian Doppler first proposed it in 1842.

But a similar effect can be observed when something rotates as well, scientists say.

"There is plenty of evidence of the rotational Doppler effect in large bodies, such as a spinning planet or galaxy," Thomas said. "When a planet rotates, the light coming from it shifts to higher frequency on the side spinning toward you and a lower frequency on the side spinning away from you. But this same basic force is at work even on the molecular level."

In astrophysics, this rotational Doppler effect has been used to determine the rotational velocity of things such as planets. But in the new study, scientists from Japan, Sweden, France and the United States provided the first experimental proof that the same thing happens even with molecules.

At this tiny level, they found, the rotational Doppler effect can be even more important than the linear motion of the molecules, the study showed.

The findings are expected to have application in a better understanding of molecular spectroscopy, in which the radiation emitted from molecules is used to study their makeup and chemical properties. It is also relevant to the study of high energy electrons, Thomas said.

"There are some studies where a better understanding of this rotational Doppler effect will be important," Thomas said. "Mostly it's just interesting. We've known about the Doppler effect for a very long time but until now have never been able to see the rotational Doppler effect in molecules."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Oregon State University, via EurekAlert!, a service of AAAS.

Journal Reference:

T. D. Thomas, E. Kukk, K. Ueda, T. Ouchi, K. Sakai, T. X. Carroll, C. Nicolas, O. Travnikova, and C. Miron. Experimental observation of rotational Doppler broadening in a molecular system. Physical Review Letters, Accepted Apr 12, 2011

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.


View the original article here

Wednesday, 25 May 2011

Doppler effect found even at molecular level -- 169 years after its discovery

ScienceDaily (May 11, 2011) — Whether they know it or not, anyone who's ever gotten a speeding ticket after zooming by a radar gun has experienced the Doppler effect -- a measurable shift in the frequency of radiation based on the motion of an object, which in this case is your car doing 45 miles an hour in a 30-mph zone.

But for the first time, scientists have experimentally shown a different version of the Doppler effect at a much, much smaller level -- the rotation of an individual molecule. Prior to this such an effect had been theorized, but it took a complex experiment with a synchrotron to prove it's for real.

"Some of us thought of this some time ago, but it's very difficult to show experimentally," said T. Darrah Thomas, a professor emeritus of chemistry at Oregon State University and part of an international research team that just announced its findings in Physical Review Letters, a professional journal.

Most illustrations of the Doppler effect are called "translational," meaning the change in frequency of light or sound when one object moves away from the other in a straight line, like a car passing a radar gun. The basic concept has been understood since an Austrian physicist named Christian Doppler first proposed it in 1842.

But a similar effect can be observed when something rotates as well, scientists say.

"There is plenty of evidence of the rotational Doppler effect in large bodies, such as a spinning planet or galaxy," Thomas said. "When a planet rotates, the light coming from it shifts to higher frequency on the side spinning toward you and a lower frequency on the side spinning away from you. But this same basic force is at work even on the molecular level."

In astrophysics, this rotational Doppler effect has been used to determine the rotational velocity of things such as planets. But in the new study, scientists from Japan, Sweden, France and the United States provided the first experimental proof that the same thing happens even with molecules.

At this tiny level, they found, the rotational Doppler effect can be even more important than the linear motion of the molecules, the study showed.

The findings are expected to have application in a better understanding of molecular spectroscopy, in which the radiation emitted from molecules is used to study their makeup and chemical properties. It is also relevant to the study of high energy electrons, Thomas said.

"There are some studies where a better understanding of this rotational Doppler effect will be important," Thomas said. "Mostly it's just interesting. We've known about the Doppler effect for a very long time but until now have never been able to see the rotational Doppler effect in molecules."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Oregon State University, via EurekAlert!, a service of AAAS.

Journal Reference:

T. D. Thomas, E. Kukk, K. Ueda, T. Ouchi, K. Sakai, T. X. Carroll, C. Nicolas, O. Travnikova, and C. Miron. Experimental observation of rotational Doppler broadening in a molecular system. Physical Review Letters, Accepted Apr 12, 2011

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.


View the original article here