How Do We Know When Voyager Reaches Interstellar Space?
You Are Here, Voyager: This artist's concept puts huge solar system distances in perspective. The scale bar is measured in astronomical units (AU), with each set distance beyond 1 AU representing 10 times the previous distance. Each AU is equal to the distance from the sun to the Earth. It took from 1977 to 2013 for Voyager 1 to reach the edge of interstellar space. Image Credit: NASA/JPL-Caltech
Whether and when NASA's Voyager 1 spacecraft, humankind's most distant object, broke through to interstellar space, the space between stars, has been a thorny issue. For the last year, claims have surfaced every few months that Voyager 1 has "left our solar system." Why has the Voyager team held off from saying the craft reached interstellar space until now?
"We have been cautious because we're dealing with one of the most important milestones in the history of exploration," said Voyager Project Scientist Ed Stone of the California Institute of Technology in Pasadena. "Only now do we have the data -- and the analysis -- we needed."
Basically, the team needed more data on plasma, which is ionized gas, the densest and slowest moving of charged particles in space. (The glow of neon in a storefront sign is an example of plasma.) Plasma is the most important marker that distinguishes whether Voyager 1 is inside the solar bubble, known as the heliosphere, which is inflated by plasma that streams outward from our sun, or in interstellar space and surrounded by material ejected by the explosion of nearby giant stars millions of years ago. Adding to the challenge: they didn't know how they'd be able to detect it.
"We looked for the signs predicted by the models that use the best available data, but until now we had no measurements of the plasma from Voyager 1," said Stone.
Scientific debates can take years, even decades to settle, especially when more data are needed. It took decades, for instance, for scientists to understand the idea of plate tectonics, the theory that explains the shape of Earth's continents and the structure of its sea floors. First introduced in the 1910s, continental drift and related ideas were controversial for years. A mature theory of plate tectonics didn't emerge until the 1950s and 1960s. Only after scientists gathered data showing that sea floors slowly spread out from mid-ocean ridges did they finally start accepting the theory. Most active geophysicists accepted plate tectonics by the late 1960s, though some never did.
Voyager 1 is exploring an even more unfamiliar place than our Earth's sea floors -- a place more than 11 billion miles (17 billion kilometers) away from our sun. It has been sending back so much unexpected data that the science team has been grappling with the question of how to explain all the information. None of the handful of models the Voyager team uses as blueprints have accounted for the observations about the transition between our heliosphere and the interstellar medium in detail. The team has known it might take months, or longer, to understand the data fully and draw their conclusions.
"No one has been to interstellar space before, and it's like traveling with guidebooks that are incomplete," said Stone. "Still, uncertainty is part of exploration. We wouldn't go exploring if we knew exactly what we'd find."
The two Voyager spacecraft were launched in 1977 and, between them, had visited Jupiter, Saturn, Uranus and Neptune by 1989. Voyager 1's plasma instrument, which measures the density, temperature and speed of plasma, stopped working in 1980, right after its last planetary flyby. When Voyager 1 detected the pressure of interstellar space on our heliosphere in 2004, the science team didn't have the instrument that would provide the most direct measurements of plasma. Instead, they focused on the direction of the magnetic field as a proxy for source of the plasma. Since solar plasma carries the magnetic field lines emanating from the sun and interstellar plasma carries interstellar magnetic field lines, the directions of the solar and interstellar magnetic fields were expected to differ.
Most models told the Voyager science team to expect an abrupt change in the magnetic field direction as Voyager switched from the solar magnetic field lines inside our solar bubble to those in interstellar space. The models also said to expect the levels of charged particles originating from inside the heliosphere to drop and the levels of galactic cosmic rays, which originate outside the heliosphere, to jump.
In May 2012, the number of galactic cosmic rays made its first significant jump, while some of the inside particles made their first significant dip. The pace of change quickened dramatically on July 28, 2012. After five days, the intensities returned to what they had been. This was the first taste of a new region, and at the time Voyager scientists thought the spacecraft might have briefly touched the edge of interstellar space.
By Aug. 25, when, as we now know, Voyager 1 entered this new region for good, all the lower-energy particles from inside zipped away. Some inside particles dropped by more than a factor of 1,000 compared to 2004. The levels of galactic cosmic rays jumped to the highest of the entire mission. These would be the expected changes if Voyager 1 had crossed the heliopause, which is the boundary between the heliosphere and interstellar space. However, subsequent analysis of the magnetic field data revealed that even though the magnetic field strength jumped by 60 percent at the boundary, the direction changed less than 2 degrees. This suggested that Voyager 1 had not left the solar magnetic field and had only entered a new region, still inside our solar bubble, that had been depleted of inside particles.
Then, in April 2013, scientists got another piece of the puzzle by chance. For the first eight years of exploring the heliosheath, which is the outer layer of the heliosphere, Voyager's plasma wave instrument had heard nothing. But the plasma wave science team, led by Don Gurnett and Bill Kurth at the University of Iowa, Iowa City, had observed bursts of radio waves in 1983 to 1984 and again in 1992 to 1993. They deduced these bursts were produced by the interstellar plasma when a large outburst of solar material would plow into it and cause it to oscillate. It took about 400 days for such solar outbursts to reach interstellar space, leading to an estimated distance of 117 to 177 AU (117 to 177 times the distance from the sun to the Earth) to the heliopause. They knew, though, that they would be able to observe plasma oscillations directly once Voyager 1 was surrounded by interstellar plasma.
Then on April 9, 2013, it happened: Voyager 1's plasma wave instrument picked up local plasma oscillations. Scientists think they probably stemmed from a burst of solar activity from a year before, a burst that has become known as the St. Patrick's Day Solar Storms. The oscillations increased in pitch through May 22 and indicated that Voyager was moving into an increasingly dense region of plasma. This plasma had the signatures of interstellar plasma, with a density more than 40 times that observed by Voyager 2 in the heliosheath.
Gurnett and Kurth began going through the recent data and found a fainter, lower-frequency set of oscillations from Oct. 23 to Nov. 27, 2012. When they extrapolated back, they deduced that Voyager had first encountered this dense interstellar plasma in August 2012, consistent with the sharp boundaries in the charged particle and magnetic field data on August 25.
Stone called three meetings of the Voyager team. They had to decide how to define the boundary between our solar bubble and interstellar space and how to interpret all the data Voyager 1 had been sending back. There was general agreement Voyager 1 was seeing interstellar plasma, based on the results from Gurnett and Kurth, but the sun still had influence. One persisting sign of solar influence, for example, was the detection of outside particles hitting Voyager from some directions more than others. In interstellar space, these particles would be expected to hit Voyager uniformly from all directions.
"Now that we had actual measurements of the plasma environment - by way of an unexpected outburst from the sun - we had to reconsider why there was still solar influence on the magnetic field and plasma in interstellar space," Stone said. "The path to interstellar space has been a lot more complicated than we imagined."
Stone discussed with the Voyager science group whether they thought Voyager 1 had crossed the heliopause. What should they call the region were Voyager 1 is?
"In the end, there was general agreement that Voyager 1 was indeed outside in interstellar space," Stone said. "But that location comes with some disclaimers - we're in a mixed, transitional region of interstellar space. We don't know when we'll reach interstellar space free from the influence of our solar bubble."
So, would the team say Voyager 1 has left the solar system? Not exactly - and that's part of the confusion. Since the 1960s, most scientists have defined our solar system as going out to the Oort Cloud, where the comets that swing by our sun on long timescales originate. That area is where the gravity of other stars begins to dominate that of the sun. It will take about 300 years for Voyager 1 to reach the inner edge of the Oort Cloud and possibly about 30,000 years to fly beyond it. Informally, of course, "solar system" typically means the planetary neighborhood around our sun. Because of this ambiguity, the Voyager team has lately favored talking about interstellar space, which is specifically the space between each star's realm of plasma influence.
"What we can say is Voyager 1 is bathed in matter from other stars," Stone said. "What we can't say is what exact discoveries await Voyager's continued journey. No one was able to predict all of the details that Voyager 1 has seen. So we expect more surprises."
Voyager 1, which is working with a finite power supply, has enough electrical power to keep operating the fields and particles science instruments through at least 2020, which will mark 43 years of continual operation. At that point, mission managers will have to start turning off these instruments one by one to conserve power, with the last one turning off around 2025.
Voyager 1 will continue sending engineering data for a few more years after the last science instrument is turned off, but after that it will be sailing on as a silent ambassador. In about 40,000 years, it will be closer to the star AC +79 3888 than our own sun. (AC +79 3888 is traveling toward us faster than we are traveling towards it, so while Alpha Centauri is the next closest star now, it won't be in 40,000 years.) And for the rest of time, Voyager 1 will continue orbiting around the heart of the Milky Way galaxy, with our sun but a tiny point of light among many.
The Voyager spacecraft were built and continue to be operated by NASA's Jet Propulsion Laboratory, in Pasadena, Calif. Caltech manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.
For more information about Voyager, visit: http://www.nasa.gov/voyager
16 Apr 2013
Green Nebula VIDEO From ESO Zooms In On 'Ghostly' Gas Clouds
Posted: 04/12/2013 9:10 am EDT | Updated: 04/16/2013 9:51 pm EDT
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There were Verticals By: Miriam Kramer
Published: 04/10/2013 10:27 AM EDT on SPACE.com
An amazing new photo from a telescope in Chile has captured the most detailed view yet of a green glowing blob 3,300 light-years away from Earth.
The new image, released today (April 10) by the European Southern Observatory
, shows the planetary nebula IC 1295 like it has never been seen before. This picture, which ESO scientists dubbed "ghostly," marks the first time the nebula has been imaged such unprecedented detail.
"It has the unusual feature of being surrounded by multiple shells that make it resemble a microorganism seen under a microscope, with many layers corresponding to the membranes of a cell," officials from the European Southern Observatory wrote in a statement.ESO offiials released a video tour of the nebula
as well (see video above).
The formation of a planetary nebula
marks one of the final chapters in the life of a star like the Earth's sun. Once the yellow star depletes its fuel, it collapses in on itself creating huge shells of gas — like the green ones that appear in the new photo.The IC 1295 nebula resides in "the shield" constellation, Scutum, and the bubble-like nebula's greenish tint comes from ionized oxygen particles.
Gas like the ionized oxygen is "belched" out of the nebula because fusion reactions are no longer stable in the dying star's core. This gas expulsion creates the glowing clouds that envelop the bright stars that also populate that part of the sky.
"At the center of the image, you can see the burnt-out remnant of the star’s core as a bright blue-white spot at the heart of the nebula," officials from the ESO wrote. "The central star will become a very faint white dwarf and slowly cool down over many billions of years.
"Scientists using ESO's Very Large Telescope took the new photo of IC 1295. By combining three different exposures using a red, green and blue filter, the astronomers were able to create the stunning new nebula photo, showing the object in a new light.The Very Large Telescope is located in the Atacama Desert in Chile and is the "most productive individual ground-based facility," according to the ESO.Follow Miriam Kramer @mirikramer and Google+. Follow us @Spacedotcom, Facebook and Google+. Original article on SPACE.com.
Dark Matter Found? Underground Detector Finds Hints Of Elusive Particle, Physicists Say
Posted: 04/15/2013 3:57 pm EDT | Updated: 04/16/2013 5:54 pm EDT
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By: Stephanie Pappas, LiveScience.com Senior Writer
Published: 04/15/2013 03:06 PM EDT on SPACE.comDENVER —
Hints of dark matter, the mysterious stuff that makes up perhaps 85 percent of the matter in the universe, may have been observed by scientists.
But researchers are far from saying they've discovered the source of dark matter
."We're not claiming anything," warned Blas Cabrera, a Stanford University physicist speaking here today (April 15) at a meeting of the American Physical Society. The new results come from the Super Cryogenic Dark Matter Search (SuperCDMS), which takes place deep underground in the Soudan mine in northern Minnesota.
In this subterranean laboratory, researchers chill germanium and silicon to incredibly cold temperatures (near absolute zero, which is minus 459.67 degrees Fahrenheit, or minus 273.15 degrees Celsius). The chilled environment is ideal for directly detecting dark matter particles. If one passes through, hitting a frigid atom nucleus, it releases charge and heat that the scientists can detect with supersensitive instruments.
The experiment detected three events that might suggest a weakly interacting massive particle, or WIMP, passing through. WIMPs are one possible candidate that explain dark matter, which emits no light but interacts with the universe through its gravity.
However, the signals detected could also be statistical hiccups. Scientists would expect to see three or more of these WIMP-like events 5.4 percent of the time simply due to random fluctuations in the experiment. But the fluctuations detected by the experiment are in a similar energy range, which is less likely to be a random accident. In fact, the signal is 99.81 percent more likely to be WIMP than simply background fluctuations, Cabrera said.
But physicists are precise and standards for claiming a discovery are even higher than these probabilities.
The finding "does not rise anywhere near the level of discovery, nor does it rise anywhere near what we would call 'evidence for,'" Cabrera said. It is, however, a "region of interest" for future study.A prereview version of the paper reporting this region of interest is available on the physics preprint website arXiv
If the signals turn out to be evidence of WIMPs as dark matter, they suggest a particle with a mass of about 8 giga-electronvolts, or GeVs (one GeV equals 1 billion electron volts).
That mass is consistent with earlier CDMS results as well as another dark-matter-hunting experiment called CoGeNT at the U.S. Department of Energy's Pacific Northwest National Laboratory, Cabrera said, but it contradicts preliminary results seen at the international XENON Dark Matter Project, a major experiment located in Italy.
Researchers are zeroing in on dark matter from multiple angles. Earlier this month, NASA scientists announced that they'd seen hints of dark matter
from indirect measurements taken on the International Space Station. The detector, the Alpha Magnetic Spectrometer, detected 400,000 positrons, which are the antimatter "twins" of electrons. These particles may have been created when dark matter particles collided and annihilated each other. Follow Stephanie Pappas on Twitterand Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com.
11 April 2013
Space Exploration Is Key To Saving Humanity
By ALICIA CHANG 04/10/13 03:28 PM ET EDT
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LOS ANGELES -- Stephen Hawking, who spent his career decoding the universe and even experienced weightlessness, is urging the continuation of space exploration – for humanity's sake.The 71-year-old Hawking said he did not think humans would survive another 1,000 years "without escaping beyond our fragile planet."
The British cosmologist made the remarks Tuesday before an audience of doctors, nurses and employees at Cedars-Sinai Medical Center, where he toured a stem cell laboratory that's focused on trying to slow the progression of Lou Gehrig's disease.
Hawking was diagnosed with the neurological disorder 50 years ago while a student at Cambridge University. He recalled how he became depressed and initially didn't see a point in finishing his doctorate. But he continued to delve into his studies."If you understand how the universe operates, you control it in a way," he said.
Renowned for his work on black holes and the origins of the cosmos, Hawking is famous for bringing esoteric physics concepts to the masses through his best-selling books, including "A Brief History of Time," which sold more than 10 million copies worldwide. Hawking titled his hourlong lecture to Cedars-Sinai employees "A Brief History of Mine."
Hawking has survived longer than most people with Lou Gehrig's disease, also known as amyotrophic lateral sclerosis. ALS attacks nerve cells in the brain and spinal cord that control the muscles. People gradually have more and more trouble breathing and moving as muscles weaken and waste away. There's no cure and no way to reverse the disease's progression. Few people with ALS live longer than a decade.
Hawking receives around-the-clock care, can only communicate by twitching his cheek, and relies on a computer mounted to his wheelchair to convey his thoughts in a distinctive robotic monotone.
Despite his diagnosis, Hawking has remained active. In 2007, he floated like an astronaut on an aircraft that creates weightlessness by making parabolic dives.
Hawking rattled off nuggets of advice: Look up at the stars and not down at your feet. Be curious.
"However difficult life may seem, there is always something you can do and succeed at," he said.
Dr. Robert Baloh, director of Cedars-Sinai's ALS program who invited Hawking, said he had no explanation for the physicist's longevity.
During the hospital tour, Hawking viewed microscopic stem cells through a projector screen and asked questions about the research, which last year received nearly $18 million from California's taxpayer-funded stem cell institute.
Baloh said he has treated patients who lived for 10 years or more.
"But 50 years is unusual, to say the least," he said.
5 April 2013
Farthest Supernova: Hubble Space Telescope Spies UDS10Wil, Most Distant Big Star Explosion Ever Seen
Published: 04/04/2013 11:44 AM EDT on SPACE.com
Astronomers have spotted the most distant massive star explosion of its kind, a supernova that could help scientists better understand the nature of the universe.Using the Hubble Space Telescope
, scientists recently caught sight of Supernova UDS10Wil (nicknamed SN Wilson) which exploded more than 10 billion years ago. It took more than 10 billion years for the light of this violent star explosion to reach Earth.SN Wilson is known as a Type Ia supernova — a particular kind of star explosion that gives scientists a sense of how the universe has expanded over time."This new distance record holder opens a window into the early universe, offering important new insights into how these stars explode," research leader David Jones of Johns Hopkins University in Baltimore, Md., said in a statement. "We can test theories about how reliable these detonations are for understanding the evolution of the universe and its expansion." [See Amazing Pictures of Supernovas
SN Wilson is only four percent more distant than the last most distant supernova
of its kind found by Hubble, NASA officials said in a statement. However, that is still 350 million years further back in time than any other previously found star explosion.By understanding when massive stars began exploding, scientists can get a sense of how quickly the universe was seeded with the elements needed to create planets and other cosmic bodies."If supernovae were popcorn, the question is how long before they start popping?" Adam Riess, an astronomer at the Space Telescope Science Institute in Baltimore, Md., said in a statement. "You may have different theories about what is going on in the kernel. If you see when the first kernels popped and how often they popped, it tells you something important about the process of popping corn."
This work also might contribute to other work being done on what triggers these massive explosions
, a question that has plagued astronomers since the discovery of Type Ia supernovas.This discovery is also part of a three-year-initiative by the Hubble program to find the most distant supernovas. Scientists with the program hope to understand if the star explosions have changed in some way since the Big Bang birthed the universe 13.8 billion years ago.The Hubble Space Telescope was launched in 1990. It is expected to continue functioning for the next five years or so, and its successor, the James Webb Space Telescope, is scheduled for launch in 2018.The new findings will be published in an upcoming issue of "The Astrophysical Journal."
25 February 2013
Mars' Red Surface Hides Gray Rock Beneath, Curiosity Drill Sample Shows
At the center of this image from NASA's Curiosity rover is the hole in a rock called "John Klein" where the rover conducted its first sample drilling on Mars. The drilling took place on Feb. 8, 2013. Published: 02/25/2013 12:36 AM EST on SPACE.com
The Red Planet's signature color is only skin deep.NASA's Mars rover Curiosity
drilled 2.5 inches (6.4 centimeters) into a Red Planet outcrop called "John Klein" earlier this month, revealing rock that's decidedly gray rather than the familiar rusty orange of the Martian surface."We're sort of seeing a new coloration for Mars
here, and it's an exciting one to us," Joel Hurowitz, sampling system scientist for Curiosity at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., told reporters Wednesday (Feb. 20).
Mars gets its red coloration from a surface layer of dust that has undergone a rusting process, during which iron was oxidized.Curiosity's hammering drill allows scientists to peer beneath that dusty veneer for the first time ever, and the early views at John Klein — where the rover performed its first full-up drilling and sample-collection operation
— are intriguing, rover team members said.
This image from NASA's Curiosity rover shows the first sample of powdered rock extracted by the rover's drill. The image was obtained by Curiosity's Mast Camera on Feb. 20, or Sol 193, Curiosity's 193rd Martian day of operations.
The gray powder Curiosity collected "may preserve some indication of what iron was doing in these samples without the effect of some later oxidative process that would've rusted the rocks into this orange color that is sort of typical of Mars," Hurowitz said.Curiosity landed inside the Red Planet's huge Gale Crater last August, kicking off a two-year prime mission to determine whether the area could ever have supported microbial life. The 1-ton rover carries 10 different science instruments and 17 cameras, along with other tools such as its arm-mounted, rock-boring drill.The drill was the last of Curiosity's gear to get vetted and tested on the Red Planet, and the rover team is thrilled that its first run went so smoothly."It's a real big turning point for us," said Curiosity lead scientist John Grotzinger, a geologist at Caltech in Pasadena.Snagging rock powder from the depths of John Klein — which shows signs of long-ago exposure to liquid water — also cements Curiosity's place in the history books, rover team members said."This is the first time any robot, fixed or mobile, has drilled into a rock to collect a sample on Mars," said JPL's Louise Jandura, sample system chief engineer for Curiosity. "In fact, this is the first time any rover has drilled into a rock to collect a sample anywhere but on Earth."Follow SPACE.com senior writer Mike Wall on Twitter @michaeldwall or SPACE.com @Spacedotcom. We're also on Facebook and Google+.
02/25/2013 8:33 am EST
India Launches Asteroid-Hunting Satellites, Tiny Space Telescopes Into Orbit
An India Space Research Organisation PSLV rocket (Polar Satellite Launch Vehicle) launches seven satellites from the Satish Dhawan Space Centre in Sriharikota, India, on Feb. 25, 2013.
Published: 02/25/2013 07:47 AM EST on SPACE.comA rocket carrying seven new satellites, including the first spacecraft designed to hunt huge asteroids and two of the world's smallest space telescopes, launched into space Monday (Feb. 25) from an Indian spaceport.The Indian Polar Satellite Launch Vehicle blasted off
at 7:31 a.m. EST (1231 GMT) from the Satish Dhawan Space Centre in Sriharikota, India, on a mission to deliver its muti-national payloads into Earth orbit.Monday's rocket flight primarily aimed to launch the new ocean-monitoring SARAL satellite into orbit for the Indian Space Research Organisation and French Space Agency. The satellite is the first in a series of satellites created by ISRO to image the Earth, conduct space science, and carry out oceanic and atmospheric studies, ISRO officials said.Several other payloads rode piggyback on the PSLV rocket, including the $25 million Near-Earth Object Surveillance Satellite
(NEOSSat), a small spacecraft designed to seek out large asteroids in orbits that may stray near the Earth.
An artist's illustration of the NEOSSat asteroid-hunting satellite in Earth orbit.
The Canadian Space Agency mission will search for large asteroids near Earth and track space debris.
The suitcase-size satellite cannot track small space rocks like asteroid 2012 DA14, the 130-foot (40 meters) object that buzzed the Earth on Feb. 15, but scientists working with NEOSSat will use it to search for a specific types of asteroids that are at least 31 million miles (50 million kilometers) from Earth, mission scientist said. [See how NEOSSat tracks asteroids (Video)
]"NEOSSat will probably reduce the impact hazard from unknown large NEO’s [near-Earth objects] by a few percent over its lifetime, but is not designed to discover small asteroids
near the Earth that may be on collision courses," NEOSSat co-principal investigator Alan Hildebrand of the University of Calgary wrote in a statement.
Two smaller nanosatellites developed in Canada also hitched a ride into orbit alongside SARAL and NEOSSat in what their builders have billed as the world's smallest space telescope mission
. The twin satellites make up the BRIght Target Explorer (BRITE) mission, which includes two tiny cubes, each just 8 inches (20 centimeters) across and weighing less than 15.5 pounds (7 kilograms). The satellites are expected to study the brightest stars in the night sky by measuring how their brightest changes over time.
Cordell Grant putting the finishing touches to the first BRITE satellite at UTIAS-SFL
The compact satellites were designed at the Space Flight Laboratory at the University of Toronto Institute for Aerospace Studies. One of the satellites was built at the laboratory while the other was assembled by a partner team in Austria, university officials said."As their name suggests, the BRITE satellites will focus on the brightest stars in the sky including those that make up prominent constellations like Orion the Hunter," university officials explained in a statement. "These stars are the same ones visible to the naked eye, even from city centers. Because very large telescopes mostly observe very faint objects, the brightest stars are also some of the most poorly studied stars."The two BRITE nanosatellites
are part of a planned constellation that is expected to eventually number six satellites in all once complete.
The other satellites launched on India's Polar Satellite Launch Vehicle Monday were a mixed bag of spacecraft and missions. They included:SAPPHIRE:
Canada's first military satellite, a small spacecraft designed to monitor space debris and satellites within an orbit 3,728 to 24,855 miles (6,000 to 40,000 kilometers) above Earth. The satellite is expected to augment the U.S. military's existing Space Surveillance System.AAUSAT3:
A small science satellite developed in Denmark and built by students from Aalborg University.STRaND-1:
The first smartphone-powered satellite ever launched into space. The Android phone that functions as the satellite's brain will run four apps that will take photos from the satellite, test the Earth's magnetic field, monitor the health of the satellite, and allow people around the world to upload videos that will play in space on the phone.Monday's Polar Satellite Launch Vehicle C20 mission is India's first rocket launch of 2013.Follow Miriam Kramer on Twitter @mirikramer or SPACE.com @Spacedotcom. We're also on Facebook & Google+.
15 September 2011
NASA spots first planet in binary star system
NASA's Kepler space telescope, searching for planets around distant suns, has discovered a Saturn-size world orbiting two stars 200 light years from Earth, a long-sought "circumbinary" planet reminiscent of the fictional world Tatooine in the Star Wars saga."This is the first definitive detection of a circumbinary planet and the best example we have of a Tatooine-type world," said Laurance Doyle, a researcher at the SETI Institute's Carl Sagan Center for the Study of Life in the Universe and lead author of a paper in the journal Science describing the discovery."Now, we don't expect Luke Skywalker or anything else to be living on Kepler-16b, but if you could visit there, you would see a sky with two suns, just like Luke did."
An artist's concept of Kepler-16b, a Saturn-size world orbiting two stars some 200 light years from Earth.
The discovery by NASA's Kepler space telescope is a first in the ongoing search for planets beyond Earth's solar system.(Credit: NASA) Launched in March 2008, Kepler trails the Earth in its orbit around the sun, aiming a 95-megapixel camera at a patch of sky the size of an out-stretched hand that contains more than 4.5 million detectable stars. Of that total, some 300,000 are the right age, composition and brightness to host Earth-like planets. Over the life of the mission, more than 150,000 of those will be actively monitored by Kepler.The spacecraft's camera does not take pictures like other space telescopes. Instead, it acts as a photometer, continually monitoring the brightness of candidate stars in its wide field of view, on the lookout for the minute dimming that occurs when a planet passes in front of the star.By studying subtle changes in brightness from such planetary transits--comparable to watching a flea creep across a car's headlight at night--and the timing of repeated cycles, computer analysis can identify potential worlds in habitable-zone orbits.The probability of finding sun-like stars with Earth-like planets in orbits similiar to ours--and aligned so that Kepler can "see" them--is about one-half of 1 percent. But given the sample size, that still leaves hundreds of potential discoveries.Last February, the Kepler team announced the discovery of 1,235 potential "exoplanets." At that time, 15 were confirmed and since then, five more confirmations have been announced. Another batch of candidates is expected to be announced next month. But as it now stands, Kepler-16b is the spacecraft's 21st confirmed planet and the first found orbiting a binary star system.Given that binary stars abound, the Kepler discovery likely opens the door for additional findings.
A family portrait showing the Kepler-16 binary star system and its one known planet.
Given the abundance of binary systems across the Milky Way, the Kepler discovery likely opens the door to additional findings.(Credit: NASA) "This discovery is stunning," Alan Boss, a member of the Kepler team, said in a statement. "Once again, what used to be science fiction has turned into reality."The two stars at the heart of the system are some 200 light years from Earth in the constellation Cygnus.
The larger, yellow star is 69 percent as massive as the sun and the smaller red star is 20 percent as big. Kepler-16b orbits the system's center of mass every 225 days.
"When you have a binary star with planets orbiting that, the binary star produces gravitational perturbations that can be very severe for planets," said Greg Laughlin, an astronomer at the University of California, Santa Cruz. "Planets can get tossed out of the system, or tossed into one of the stars."This particular planet is far enough out, it's far enough away from the two binary stars that it effectively is feeling them as a single gravitational attraction. And while there are perturbations, those perturbations aren't severe enough to actually cause problems for the orbit.
"But unlike Tatooine, Kepler-16b, orbiting beyond the system's habitable zone where water can exist as a liquid, is not habitable. Even so, it clearly sparked the imagination of the science team."This is an example of another planetary system, a completely different type that we've never seen before," Doyle said. "That's why everybody's making a big deal of it. Nobody's ever seen a place like this before, with one exception. I seem to remember seeing a place like this about 30 years ago in a galaxy far, far away."
John Knoll, a visual effects supervisor for film maker George Lucas' Industrial Light & Magic for three Star Wars movies, told reporters no one worried at the time that Tatooine did not reflect prevailing scientific theory.
"I don't think George particularly concerned himself that the leading theory of planet formation made this setting somewhat unlikely," he said. "But Kepler-16b is unambiguous and dramatic proof that planets do form around binaries. It's possible there's a real Tatooine out there, a planet like that could really exist."Re-imagining a scene from the first Star Wars movie, Doyle described a sunset on Kepler-16b: "Sometimes, the red star would set first, sometimes the orange star, sometimes they'd set touching each other, sometimes set together. So you'd get this very dynamic sunset. It's never two sunsets are the same."If Skywalker could stand on Kepler-16b, he would see two shadows, Doyle said, adding that "if you wanted to tell the time by sundial, you'd need calculus, you know?"
Read more: http://news.cnet.com/8301-19514_3-20106952-239/nasa-spots-first-planet-in-binary-star-system/#ixzz1YcaMZwx1
Monster Storm Detected on Brown Dwarf Star
Monster Storm Rages on Tiny Misfit Star
M Clara Moskowitz, SPACE.com Senior Writer
Date: 13 September 2011 Time: 06:00 AM ET
Extreme brightness changes observed on a nearby tiny brown dwarf star may indicate a storm grander than any yet seen on an alien world, scientists say.
Small, dim star appears to be wracked by a mega storm more violent than any weather yet seen on another world, astronomers announced. CREDIT: Jon Lomberg
The star, called a brown dwarf, is more massive than a giant planet but much lighter than most stars. Over a period of several hours, the star exhibited the largest brightness variations ever seen on a cool brown dwarf.
"We found that our target's brightness changed by a whopping 30 percent in just under eight hours," graduate student Jacqueline Radigan of the University of Toronto said in a statement. "The best explanation is that brighter and darker patches of its atmosphere are coming into our view as the brown dwarf spins on its axis."
25 August 2011
Attention all astronomers! There is a new Type Ia supernova that has been seen in the nearby spiral galaxy M101, and it’s very young — currently only about a day old! This is very exciting news; getting as much data on this event as possible is critical. Most likely professional astronomers are already aware of the supernova, since observations have already been taken by Swift (no X-rays have yet been seen, but it’s early yet) and Hubble observations have been scheduled. Still, I would urge amateur astronomers to take careful observations of the galaxy. [As an aside, I'll note that this supernova won't get bright enough to see naked eye and poses no threat at all to us here on Earth. It may be visible in decent-sized telescopes, though, and as you'll see this may be a very important event in the annals of astronomy.]
So why is this a big deal?
First of all, a supernova is an exploding star — one of the most violent events in the Universe. There are different kinds of supernovae, but a Type Ia occurs, it’s thought, when a superdense white dwarf — the remnant core of a dead star — siphons material off a companion star. If enough material piles on top of the white dwarf, it can suddenly start to fuse hydrogen into helium. This starts a runaway effect, and the entire star explodes. This supernova can release so much energy it can actually outshine its host galaxy! If you want more details, I’ve written about Type Ia supernovae before: Astronomers spot ticking supernova time bomb and Dwarf merging makes for an explosive combo. So this kind of supernova is incredibly bright, making them easy to spot over vast distances. These events are very important, because we think that each Type Ia supernova is very similar in the way it explodes, making them useful as benchmarks in gauging distances to very distant galaxies. In fact, it is the study of these explosions that has helped us nail down how fast the Universe is expanding, and also led to the discovery of dark energy. Clearly, the more we know about them, the better.
Given M101′s close distance, this new supernova will be relatively easy to study. And the best part is that the exploding star was caught young: most of the ones we see are far away, and too faint to be seen until they start to reach their maximum brightness after a few days. Getting data on them early is absolutely critical for understanding them, and it’s the hardest part of all this. I am not exaggerating to say this new supernova could be a linchpin in our understanding of these events.
Interestingly, Hubble took images of this galaxy in 2002, and astronomers dug up the archived images and looked at the spot of the supernova to see if anything was there back then. Nothing shows up in the blue filter, but in the red (shown here) there are two stars very close to the position of the future supernova (the circle is centered on the best measurement of the supernova’s position). From their brightness and color, both of these stars are red giants, stars like the Sun but near the ends of their lives. That would fit with the Type Ia supernova: red giants are so big that if there’s a white dwarf nearby, it could suck up their matter and start the chain of events that led to its doom. Further observations may pin this down. If one of these stars is what fed the supernova, that’s seriously cool; there are only a handful of supernova progenitor stars that have ever been seen.
All in all, this is pretty much a big deal. The galaxy is close, pretty, a bit odd, and is hosting the nearest Type Ia supernova seen in decades which was caught when it was less than a day old. I’m excited! I know a lot of telescopes will be aimed at the northern skies over the next few days, and I’ll be very interested to find out what they see.
Image credits: Hubble M101 image: NASA, ESA, K. Kuntz (JHU), F. Bresolin (University of Hawaii), J. Trauger (Jet Propulsion Lab), J. Mould (NOAO), Y.-H. Chu (University of Illinois, Urbana), and STScI; Type Ia art: NASA/CXC/M.Weiss; Hubble image: NASA/ESA/Hubble. Tip o’ the dew shield to paulwarren73.
News:UC-Santa Cruz astronomers discover pristine gas - cloudy relics of The Big Bang
Posted: 11/10/2011 04:51:02 PM PST
Updated: 11/11/2011 01:23:12 PM PST
For the first time, astronomers have detected ancient and pristine clouds of primordial gas, conceived when the universe was a very young, dark and lonely place.
This long-sought discovery of 12-billion-year-old pockets of gas by UC Santa Cruz scientists offers a stunning snapshot of early cosmic history -- and adds more support to the widely accepted big bang theory about the origin of elements in our universe.
"It's thrilling. It describes all that we've been looking for," said J. Xavier Prochaska, professor of astronomy and astrophysics, whose study is published in Thursday's issue of the journal Science.
Staring into deep time within two patches of dark sky -- one in the constellation Leo and the other Ursa Major -- the team found clouds of hydrogen and a hydrogen isotope, called deuterium. Those two original elements, relics of the big bang -- a mega-explosion that led to the expansion of the universe -- are uncontaminated by more recent elements like carbon, nitrogen and oxygen.
The ancestral clouds are very, very faint, not visible to the naked eye. But powerful computers in a UC Santa Cruz basement can analyze their spectral images, captured by Hawaii's Keck Telescope.The discovery is significant because it props up the big bang theory of the origin of the elements. In the beginning, according to the hypothesis, hydrogen and helium were created during "the dark ages" of the universe -- through nuclear reactions in the first few moments of creation.
But that could not be proven until now, because astronomers were able to detect only much newer elements, such as our beloved oxygen.
The primordial gas provided fuel for the very first stars -- lighting up the darkness. These early stars were monsters that burned hot, lived fast and died young. Their deaths sent newer elements exploding into space, seeding galaxies with everything necessary for life.
More profoundly, the UCSC discovery is a reminder of the illuminating power of human reason, and how scientists can overcome seemingly insoluble problems using technology.
"We've been trying to find such pockets, because there was good reason to think they exist," said Prochaska. "We've been aggressively looking for material that would match the theory.
"This is very pristine gas -- exactly what the theory predicts," he said. "It's material not polluted by stars or galaxies.
"Turning the scientific process on its head, the discovery was made by the actual absence of data -- what couldn't be seen,can't be found, it reveals the composition of that gas."
All gases, and other elements, have unique "spectral" fingerprint. So the UCSC team did a spectrographic analysis of the fingerprints of the light. The light came from a super-bright quasar; fortunately, the clouds happened to be right in front of it.
The scientists' computers spread out this light into a broad spectrum of different wavelengths -- making it possible to identify which wavelengths were absorbed by the gas.
Looking for wavelengths of hydrogen, "we don't see it. That light is removed," meaning it is contained within the clouds, Prochaska said.Ditto for deuterium. Scientists believe that the universe once had more deuterium than it does today -- and the deuterium-to-hydrogen ratio in the gas clouds matches big bang predictions.
"It's doing astronomy backwards," explained Prochaska. "Most people look at stars, galaxies -- things like color, shape, whatever. ... But we don't care about the light we receive. We care about light that we don't receive. The dark spots."He added, "We're doing science in silhouette -- studying that light that doesn't get here, due to the gas.
"We get excited about nothing," he joked. "When it was immediately clear that nothing was there, that really floored us."
Poignantly, these clouds likely no longer exist.
Powerful telescopes see distant objects as they were far back in time, not now. It takes a long time for light to travel across the universe.
"It's very different today," said Prochaska. "They're probably not there at all."
This simulation of galaxy formation shows streams of gas feeding the growing galaxy. The newly discovered gas clouds may be part of a "cold flow" of gas similar to these streams. Courtesy Daniel Ceverino, Avishai Dekel and Joel Primack