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Tuesday
Mar182014

First Direct Evidence of Cosmic Inflation

Researchers from the BICEP2 collaboration today announced the first direct evidence for this cosmic inflation. Their data also represent the first images of gravitational waves, or ripples in space-time. These waves have been described as the "first tremors of the Big Bang." Finally, the data confirm a deep connection between quantum mechanics and general relativity.

"Detecting this signal is one of the most important goals in cosmology today. A lot of work by a lot of people has led up to this point," said John Kovac (Harvard-Smithsonian Center for Astrophysics), leader of the BICEP2 collaboration.

These groundbreaking results came from observations by the BICEP2 telescope of the cosmic microwave background -- a faint glow left over from the Big Bang. Tiny fluctuations in this afterglow provide clues to conditions in the early universe. For example, small differences in temperature across the sky show where parts of the universe were denser, eventually condensing into galaxies and galactic clusters.

Since the cosmic microwave background is a form of light, it exhibits all the properties of light, including polarization. On Earth, sunlight is scattered by the atmosphere and becomes polarized, which is why polarized sunglasses help reduce glare. In space, the cosmic microwave background was scattered by atoms and electrons and became polarized too.

"Our team hunted for a special type of polarization called 'B-modes,' which represents a twisting or 'curl' pattern in the polarized orientations of the ancient light," said co-leader Jamie Bock (Caltech/JPL).

Gravitational waves squeeze space as they travel, and this squeezing produces a distinct pattern in the cosmic microwave background. Gravitational waves have a "handedness," much like light waves, and can have left- and right-handed polarizations.

"The swirly B-mode pattern is a unique signature of gravitational waves because of their handedness. This is the first direct image of gravitational waves across the primordial sky," said co-leader Chao-Lin Kuo (Stanford/SLAC).

The team examined spatial scales on the sky spanning about one to five degrees (two to ten times the width of the full Moon). To do this, they traveled to the South Pole to take advantage of its cold, dry, stable air.

"The South Pole is the closest you can get to space and still be on the ground," said Kovac. "It's one of the driest and clearest locations on Earth, perfect for observing the faint microwaves from the Big Bang."

They were surprised to detect a B-mode polarization signal considerably stronger than many cosmologists expected. The team analyzed their data for more than three years in an effort to rule out any errors. They also considered whether dust in our galaxy could produce the observed pattern, but the data suggest this is highly unlikely.

"This has been like looking for a needle in a haystack, but instead we found a crowbar," said co-leader Clem Pryke (University of Minnesota).

When asked to comment on the implications of this discovery, Harvard theorist Avi Loeb said, "This work offers new insights into some of our most basic questions: Why do we exist? How did the universe begin? These results are not only a smoking gun for inflation, they also tell us when inflation took place and how powerful the process was."

BICEP2 is the second stage of a coordinated program, the BICEP and Keck Array experiments, which has a co-PI structure. The four PIs are John Kovac (Harvard), Clem Pryke (UMN), Jamie Bock (Caltech/JPL), and Chao-Lin Kuo (Stanford/SLAC). All have worked together on the present result, along with talented teams of students and scientists. Other major collaborating institutions for BICEP2 include the University of California at San Diego, the University of British Columbia, the National Institute of Standards and Technology, the University of Toronto, Cardiff University, Commissariat à l'Energie Atomique.

BICEP2 is funded by the National Science Foundation (NSF). NSF also runs the South Pole Station where BICEP2 and the other telescopes used in this work are located. The Keck Foundation also contributed major funding for the construction of the team’s telescopes. NASA, JPL, and the Moore Foundation generously supported the development of the ultra-sensitive detector arrays that made these measurements possible.

Technical details and journal papers can be found on the BICEP2 release website:

http://bicepkeck.org

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

David A. Aguilar
Director of Public Affairs
Harvard-Smithsonian Center for Astrophysics
617-495-7462
daguilar@cfa.harvard.edu

Christine Pulliam
Public Affairs Specialist
Harvard-Smithsonian Center for Astrophysics
617-495-7463
cpulliam@cfa.harvard.edu

Source:

http://www.cfa.harvard.edu/news/2014-05

Sunday
Sep222013

Evidence of Extraterrestrial Life found in Earth's Atmosphere --Challenged!

Scientists from the University of Sheffield claim they have discovered proof of extraterrestrial life. Their evidence? The team launched a balloon 16 miles into the stratosphere, and it came back carrying small biological organisms. Professor Milton Wainwright, who led the team, is "95 percent certain that these biological entities are of extraterrestrial origin."

"If we're right, it means that there's life in space, and it's coming to earth. It means that life on earth probably originated in space. Most people will assume that these biological particles must have just drifted up to the stratosphere from Earth, but it is generally accepted that a particle of the size found cannot be lifted from Earth to heights of, for example, 27 kilometers."

But astronomer Phil Plait say's it's looks like the 'biological material' the scientists found probably didn't come from outer space: "There are a lot of reasons to think this claim is unfounded, but one is right in their very paper. The diatom ... appears clean, even pristine. As they themselves say: It is noticeable that the diatom fragment is remarkably clean and free of soil or other solid material ... which would be incredibly unlikely if it did come from a comet or a meteoroid, he wrote in Slate.

Plait also doubts the idea that a microorganism from Earth couldn't be held aloft by wind and turbulence for a long period of time acccording to the University of Sheffield scientists' theory.

However, the scientist who led the research, Chandra Wickramasinghe, Director of the Buckingham Centre for Astrobiology, University of Buckingham, is a proponent of the theory of panspermia, which according to Plait, could affect his research. Wickramasinghe and the late English astronomer Sir Fred Hoyle co-developed a theory known as "panspermia," which suggests that life exists throughout the universe and is distributed by meteoroids and asteroids.

In a paper called "Fossil Diatoms In A New Carbonaceous Meteorite" that appeared in the controversila Journal of Cosmology, Wickramasinghe claimed to have found strong evidence that life exists throughout the universe based on his study of the reported remains of a large meteorite (see image below right) that fell near the Sri Lanka village of Polonnaruwa on Dec. 29, 2012.

"Wickramasinghe jumps on everything, with little or no evidence, and says it's from outer space, so I think there's a case to be made for a bias on his part," says Plait reported in Slate.

The scientists still have one more test to perform --"isotope fractionation"--which will determine whether the ratio of certain isotopes is consistent with that of organisms from earth. Professor Milton Wainwright is confident that they they be extraterrestrial in origin. Stay tuned!

The image at the top of the page shows organic carbon in a ordinary chondritic meteorite obtained using a scanning transmission X-ray microscope at the Advanced Light Source, Lawrence Berkeley Laboratory. The sample was obtained using a focused ion beam electron microscope (mill). In this image, carbon is highlighed in red, iron in blue and calcium is green.The history of the early Solar System is recorded in the molecular structure of extraterrestrial organic solids. 

The Daily Galaxy via Slate and PBS

Image credit: https://www.gl.ciw.edu/news/extraterrestrial_carbon, provided by George Cody, Conel Alexander, and Larry Nittler.

Source:

http://www.dailygalaxy.com/my_weblog/2013/09/claims-of-extraterrestrial-life-found-in-earths-stratosphere-challenged.html

Sunday
Jun092013

"Black Widow Pulsar"--At the Top of Strange Phenomena in the Universe?

The pulsar, a.k.a. the "Black Widow," is moving through the galaxy at a speed of almost a million kilometers per hour. A bow shock wave due to this motion is visible to optical telescopes, shown in this image as the greenish crescent shape. The pressure behind the bow shock creates a second shock wave that sweeps the cloud of high-energy particles back from the pulsar to form the cocoon.

This composite Chandra X-ray (red/white) and optical (green/blue) image reveals an elongated cloud, or cocoon, of high-energy particles flowing behind the rapidly rotating pulsar, B1957+20 (white point-like source). The pulsar, a.k.a. the "Black Widow" pulsar, is moving through the galaxy at a speed of almost a million kilometers per hour. A bow shock wave due to this motion is visible to optical telescopes, shown in this image as the greenish crescent shape. The pressure behind the bow shock creates a second shock wave that sweeps the cloud of high-energy particles back from the pulsar to form the cocoon.

The pulsar is emitting intense high-energy radiation that appears to be destroying a companion star through evaporation. It is one of a class of extremely rapid rotating neutron stars called millisecond pulsars. Calculations suggest that the "black widow" will evaporate away its companion in about a billion years.

These objects are thought to be very old neutron stars that have been spun up to rapid rotation rates with millisecond periods by pulling material off their companions. The advanced age, very rapid rotation rate, and relatively low magnetic field of millisecond pulsars put them in a separate class from young pulsars, such as the Crab Nebula.

Pulsars rank at or near the top of freaky phenomena found in our Universe. In the early 1930s, California Institute of Technology astrophysicist, Fred Zwicky, an immigrant from Bulgaria, focused his attention on a question that had long troubled astronomers: the appearance of random, unexplained points of light, new stars.

It occurred to Zwicky that if a star collapsed to the sort of density found in the core of atoms, the result would be an unimaginably compacted core: atoms would be crushed together with their electrons squeezed into the nucleus, forming neutrons and a neutron star, with a core so dense that a single spoonful would weigh 200 billion pounds. But there's more, Zwicky concluded: with the collapse of the star there would be huge amounts of leftover energy that would result in a massive explosion, the biggest in the known universe that we called today supernovas.

Most neutron stars house incredibly large magnetic fields. If they are spinning rapidly they make fabulous clocks, cosmic radio beacons we call pulsars. Pulsars can keep time to an accuracy better that one microsecond per year. Some pulsars generate more than 1000 pulses per second, which means, as Lawrence Krauss wrote in The Physics of Star Trek, that an object with the mass of the Sun packed into an object 10 to 20 kilometers across is rotating over 1000 times per second, or more that half the speed of light!

Source:

http://www.dailygalaxy.com/my_weblog/2013/06/black-widow-pulsar-at-the-top-of-strange-phenomena-in-the-universe.html

Sunday
Jun092013

2011 Draconid Meteor Shower Deposited a Ton of Meteoritic Material On Earth

With more than 400 meteors per hour, the 2011 Draconid meteor shower was one of the most intense meteor showers in the last decade. (Credit: © F. Pruneda)

About a ton of material coming from comet 21P/Giacobini-Zinner was deposited in the Earth's atmosphere on October 8th and 9th, 2011 during one of the most intense showers of shooting starts in the last decade, which registered an activity of more than 400 meteors per hour.

Every 6.6 years, the comet Giacobini-Zinner circulates through the inner solar system and passes through the perihelion, the closest point to the Sun of its orbit. Then, the comet sublimates the ices and ejects a large number of particles that are distributed in filaments. The oldest of these particles have formed a swarm that Earth passes trough every year in early October. The result is a Draconid meteor shower -- meteors from this comet come from the northern constellation Draco -- which hits Earth's atmosphere at about 75,000 km/h, a relatively slow speed in comparison with other meteoric swarms.

Josep Maria Trigo, researcher from the CSIC Institute of Space Sciences (ICE), states: "When a comet approaches the Sun, it sublimates part of its superficial ice and the gas pressure drives a huge number of particles that adopt orbits around the Sun, forming authentic swarms. The study shows that in the evening from October 8th to 9th 2011, the Earth intercepted three dense spindles of particles left behind by the comet when it crossed through the perihelion."

The researchers, who published their results in the Monthly Notices of the Royal Astronomical Society magazine, have obtained the orbits of twenty meteors in the solar system. Thus, they have confirmed the origin of the particles that caused the outbreak in that periodic comet. For this, they have count on 25 video-detection stations operated by the Spanish Meteor and Firewall Network (SPMN) and the collaboration of amateur astronomers.

Two of those filaments of meteoroids, which had been theoretically predicted already, have been identified by scientists with those left by the comet in 1874, 1894 and 1900. Nevertheless, researchers have confirmed that there was another dense region intercepted by Earth which had not been predicted and that involves a new challenge for theoretical models.

In a second article, researchers analyze the chemical composition of six fireballs from that swarm of the comet recorded during the outbreak. José María Madiedo, researcher from the University of Huelva and coordinator of this second study, asserts: "One of them, with an initial mass of 6 kg and nearly half a meter in diameter, named Lebrija in honor of the city it over flew, came to compete with the brightness of the moon that night."

The six analyzed fragments have a possibly similar composition to the carbonaceous chondrites (a type of organic-rich meteorites) but they are much more fragile. Trigo emphasizes: "They don't seem to have suffered any chemical alteration during their brief stay in the interplanetary environment, which turns out to be very interesting to confirm the astrobiological role of these particles in the continuous transportation of water and organic material to the Earth."

Source:

http://www.sciencedaily.com/releases/2013/06/130606141046.htm

Monday
Mar182013

Distant Planetary System Is a Super-Sized Solar System

Artist’s rendering of the planetary system HR 8799 at an early stage in its evolution, showing the planet HR 8799c, as well as a disk of gas and dust, and interior planets. (Credit: Dunlap Institute for Astronomy & Astrophysics; Mediafarm)

A team of astronomers, including Quinn Konopacky of the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, has made the most detailed examination yet of the atmosphere of a Jupiter-like planet beyond our Solar System.

According to Konopacky, "We have been able to observe this planet in unprecedented detail because of the advanced instrumentation we are using on the Keck II telescope, our ground-breaking observing and data-processing techniques, and because of the nature of the planetary system."

Konopacky is lead author of the paper describing the team's findings, to be published March 14th in Science Express, and March 22nd in the journal Science.

The team, using a high-resolution imaging spectrograph called OSIRIS, uncovered the chemical fingerprints of specific molecules, revealing a cloudy atmosphere containing carbon monoxide and water vapour. "With this level of detail," says Travis Barman, a Lowell Observatory astronomer and co-author of the paper, "we can compare the amount of carbon to the amount of oxygen present in the planet's atmosphere, and this chemical mix provides clues as to how the entire planetary system formed."

There has been considerable uncertainty about how systems of planets form, with two leading models, called core accretion and gravitational instability. Planetary properties, such as the composition of a planet's atmosphere, are clues as to whether a system formed according to one model or the other.

"This is the sharpest spectrum ever obtained of an extrasolar planet," according to co-author Bruce Macintosh of the Lawrence Livermore National Laboratory. "This shows the power of directly imaging a planetary system. It is the exquisite resolution afforded by these new observations that has allowed us to really begin to probe planet formation."

The spectrum reveals that the carbon to oxygen ratio is consistent with the core accretion scenario, the model thought to explain the formation of our Solar System.

The planet, designated HR 8799c, is one of four gas giants known to orbit a star 130 light-years from Earth. The authors and their collaborators previously discovered HR 8799c and its three companions back in 2008 and 2010. All the planets are larger than any in our Solar System, with masses three to seven times that of Jupiter. Their orbits are similarly large when compared to our system. HR 8799c orbits 40 times farther from its parent star than Earth orbits from the Sun; in our Solar System, that would put it well beyond the realm of Neptune.

According to the core accretion model, the star HR 8799 was originally surrounded by nothing but a huge disk of gas and dust. As the gas cooled, ice formed; this process depleted the disk of oxygen atoms. Ice and dust collected into planetary cores which, once they were large enough, attracted surrounding gas to form large atmospheres. The gas was depleted of oxygen, and this is reflected in the planet's atmosphere today as an enhanced carbon to oxygen ratio.

The core accretion model also predicts that large gas giant planets form at great distances from the central star, and smaller rocky planets closer in, as in our Solar System. It is rocky planets, not too far, nor close to the star, that are prime candidates for supporting life.

"The results suggest the HR 8799 system is like a scaled-up Solar System," says Konopacky. "And so, in addition to the gas giants far from their parent star, it would not come as a surprise to find Earth-like planets closer in."

The observations of HR 8799c were made with the Keck II 10-metre telescope in Hawaii, one of the two largest optical telescopes in the world. The telescope's adaptive optics system corrects for distortion caused by Earth's atmosphere, making the view through Keck II sharper than through the Hubble Space Telescope.

Astronomers refer to this as spatial resolution. Seeing exoplanets around stars is like trying to see a firefly next to a spotlight. Keck's adaptive optics and high spatial resolution, combined with advanced data-processing techniques, allow astronomers to more clearly see both the stellar "spotlight" and planetary "firefly."

"We can directly image the planets around HR 8799 because they are all large, young, and very far from their parent star. This makes the system an excellent laboratory for studying exoplanet atmospheres," says coauthor Christian Marois of the National Research Council of Canada. "Since its discovery, this system just keeps surprising us."

Konopacky and her team will continue to study the super-sized planets to learn more details about their nature and their atmospheres. Future observations will be made using the recently upgraded OSIRIS instrument which utilizes a new diffraction grating -- the key component of the spectrograph that separates light according to wavelength, just like a prism. The new grating was developed at the Dunlap Institute and installed in the spectrograph in December 2012.

"These future observations will tell us much more about the planets in this system," says Dunlap Fellow Konopacky. "And the more we learn about this distant planetary system, the more we learn about our own."

Source:

http://www.sciencedaily.com/releases/2013/03/130314144211.htm