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Posts Tagged ‘Space’

Physicists: Universe Almost Certainly Not a Hologram

05 Jul

By Duncan Geere, Wired UK

An astrophysicist’s attempt to measure quantum “fuzziness” — to find out if we’re living in a hologram — has been headed off at the pass by results suggesting that we’re probably not.

In October 2010, Wired.com reported on Craig Hogan’s experiments with two of the world’s most precise clocks, which he was using to try and confirm the existence of Planck units — the smallest possible chunks of space, time, mass and other properties of the universe.

Hogan’s interpretation of results from the GEO600 gravitational wave experiment had shown a quantum fuzziness — a sort of pixelation — at incredibly small scales, suggesting that what was perceive as the universe might be projected from a two-dimensional shell at its edge.

However, a European satellite that should be able to measure these small scales hasn’t found any quantum fuzziness at all, contradicting the interpretation of the GEO600 results and indicating that the pixelation of spacetime, if it exists, is considerably smaller than predicted.

By examining the polarisation of gamma-ray bursts as they reach Earth, we should be able to detect this graininess, as the polarisation of the photons that arrive here is affected by the spacetime that they travel through. The grains should twist them, changing the direction in which they oscillate so that they arrive with the same polarization. Also, higher energy gamma rays should be twisted more than lower ones.

However, the satellite detected no such twisting — there were no differences in the polarization between different energies found to the accuracy limits of the data, which are 10,000 times better than any previous readings. That means that any quantum grains that exist would have to measure 10^-48 meters or smaller.

“This is a very important result in fundamental physics and will rule out some string theories and quantum loop gravity theories,” says Philippe Laurent, a physicist at France’s Atomic Energy Commission who analyzed the data, in a press release.

Source: Wired UK

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Image: Gamma ray burst. (ESA/SPI Team/ECF)

 
 

The Moon may have the same proportion of water as Earth does [Video]

26 May
Today, a group of scientists announced that beneath the surface of the Moon there may be as much water as we have on Earth. This revelation could change everything we know about the Moon — and pave the way for lunar colonies in the next twenty years. More »
 
 

Cold, Lonely Planets More Common Than Sun-Like Stars

19 May

By Christopher Dombrowski, Ars Technica

Seems like every week astronomers find a new exoplanet, one that’s the biggest or the smallest or the hottest or most habitable. However, this week astronomers are announcing a truly unique and new class of exoplanets: Jupiter sized planets that are in extremely large orbits or completely unbound from a host star altogether. And there appear to be a lot of them, as these planets seem to be more common than main sequence stars.

Finding a planet that is not associated with a star is no easy task. In the new search, a team of researchers used a technique called gravitational microlensing. As you look at a background field of stars, if an object passes between you and one of the stars, there will be a temporary brightening of that star. This occurs as the gravity of the object bends light around itself, which acts as a lens for light from the background star, hence “gravitational lensing.” Microlensing occurs when the foreground object is too small to create measurable distortion of the background star and only a brightening is observed. This makes it an ideal detector for small, dim objects.

The mass of the lensing object determines the duration of the brightening event — the longer the duration, the more massive. A Jupiter-sized object would produce lensing event with a duration of around one day.

The odds of a microlensing event occurring are exceedingly small, as the lensing object has to line up exactly between you and the background star. To compensate, astronomers looked at 50 millions of stars over several years, which yielded 474 microlensing events. Out of those 474, 10 had durations of less than two days, consistent with a Jupiter mass object.

No host stars were observed within 10 astronomical units of the lensing object. Previous work from The Gemini Planet Imager had set limits of the population of Jupiter-sized planets in extended orbits. From that data, the astronomers were able to estimate that 75 percent of their observed planets were most likely not bound to a host star at all, and are instead loose within the galaxy.

By creating a galactic-mass density model that takes into account this new class of object, astronomers were able to predict how many of these unbound planets there might be. They found that there are ~1.8 times as many unbound Jupiter-sized object as there are main sequence stars in our galaxy.

This raises a number of questions. Did these planets from near a star only to be ejected from the system? And if they truly have never been bound to any stars, do these planets represent a new planetary formation process? In any case, these observations have discovered a whole new population of Jupiter-sized planets in the Milky Way, and there are a lot of them.

I wonder if these new planets are like our Jupiter and, like our Jupiter, have moons which are geologically active and warm. If so, these new planets may have significantly increased the number of places that life may exist.

Image: NASA/JPL-Caltech [full-resolution image]

Citation: “Unbound or distant planetary mass population detected by gravitational microlensing.” The Microlensing Observations in Astrophysics (MOA) Collaboration and The Optical Gravitational Lensing Experiment (OGLE) Collaboration. Nature, Vol. 473, Pg. 349–352, 19 May 2011. DOI: 10.1038/nature10092

Source: Ars Technica

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Still Searching: SETI Pioneer Jill Tarter Talks Shutdown, Aliens

28 Apr

For many alien enthusiasts, Jill Tarter is synonymous with the search for extraterrestrial intelligence. As the SETI Institute’s research director — and the inspiration for Jodie Foster’s character in Contact — she’s done more than anyone to raise the search for cosmic company from a fringe effort to serious science.

After receiving a TED prize in 2009, Tarter had grand plans for the Allen Telescope Array, a proposed field of 350 big-nosed radio dishes that would be the world’s only dedicated SETI telescope, as well as its most sensitive. But this week, budget cuts forced the ATA’s existing 42 dishes into hibernation mode. The rest are now just a dream.

Wired.com talked with Jill Tarter about the shutdown and what it means for the future of SETI.

Wired.com: The dishes are in hibernation mode now. What exactly does that mean?

Tarter: It means the array runs on a smaller staff. We keep the caretaker staff. We keep power on the antennas, so the cryogenics stay cold and they don’t get harmed. We just put them in a safe mode. But you can’t operate them, you can’t take data.

Wired.com: Does that mean you’re expecting to bring it back up?

Tarter: We’re doing everything we possibly can to bring it out of hibernation. But that, you know, that requires new funding.

We’re talking with the Air Force, and we’re hopeful for that. But we also need the public to step up and support SETI research, to keep that on an even keel. This unfortunate situation, coming at just the wrong time, when we were just beginning a two-year search of these Kepler worlds — we hope people understand the irony of that.

Wired.com: Tell me about the Kepler project. What were you going to do there?

‘We can expect 50 billion planets in the galaxy, and 500 million of those are likely to be habitable.’

Tarter: Before Kepler launched, we knew about a couple of hundred exoplanets. Most of those were big or right next to their stars. Not likely to be habitable. The Kepler worlds are different. There are 68 of them that are about the same size as Earth, of which it’s calculated that 54 may be in the “Goldilocks” habitable zone. And there’s 1,235 of them altogether, which [extrapolated] gives us the statistic that we can expect 50 billion planets in the galaxy, and 500 million of those are likely to be habitable.

The Kepler results have changed the way we can do our research. We can now point where we know there are likely to be good planet candidates. That’s a change. This is a fantastic new bounty of potential and information.

Wired.com: So you had specific plans to go after the Kepler planets directly?

Tarter: Yes. We’d scoped out a two-year observing program. There’s something called a “water hole” from 1 to 10 gigahertz, where the universe is naturally quiet. We want to search through that.

Wired.com: That makes it a particularly bad time to be shutting down the telescopes.

Artist's rendition inspired by data from the Kepler telescope, courtesy of NASA.

Tarter: It’s a hugely frustrating time. [SETI senior astronomer] Seth Shostak is all over the place with a great one-liner: “It’s as if the Nina, Pinta and Santa Maria were called back to dry dock.”

The other thing we’re doing now, which we’ve never done before, is trying to get the world involved. We’re trying to open up this search so that it isn’t just done in a silo by a tiny priesthood of astronomers.

Every Friday afternoon for the last year, we’ve saved and uploaded into the cloud huge amounts of data, about 10 terabytes altogether. The idea is to allow people who are good at signal processing to help us develop new algorithms to find new classes of signals. We’ve also just put out the first version of a citizen science participatory opportunity [SETIQuest Explorer], which is in beta test now. It’s our first attempt to see whether people can help us find patterns in the data that we haven’t yet built algorithms for.

Having an active global program — not just turning on your computer, installing software, walking away and never thinking about it again, but getting your brain turned on, thinking about the story, thinking about how you’re connected to the cosmos and everybody else on this planet — that’s another mission. But of course that means we have to get the telescope back on the air before we can carry through on that. Now is not a good time to stop. It’s never a good time to stop. We didn’t build these telescopes to put them into hibernation.

‘We’re trying to get the world involved. We’re trying to open up this search so that it isn’t just done in a silo by a tiny priesthood of astronomers.’

Wired.com: What other approaches are there for SETI?

There’s still [email protected], which is run by Berkeley and works on data recorded at the Arecibo Observatory. There’s a new collaborative project started by the Japanese called Project Dorothy. LOFAR, a new telescope that looks for signals at low frequency over the Netherlands, Germany, Holland and the U.K., has begun a SETI program. There’s a little bit of SETI in Australia, and SETI is still ongoing at Institute for Radio Astronomy in Argentina.

Wired.com: So there’s hope. The torch is still being carried.

Tarter: Oh, definitely. I’m working harder this morning and yesterday than I ever have before, trying to get the message out. We’re going to find different federal funds, but we really need people invested and engaged and supporting us to keep the funding stable.

Wired.com: How important is it to have continuous observations? If we’re targeting individual Kepler planets, the planets will still be there in 10 years.

Tarter: Sure, the planets will still be there. On the other hand, would it make a difference if you discovered a signal today, as opposed to waiting 10 years? I think it would, [especially] in getting people to recognize that their differences are small. That message is an important one.

Wired.com: What do you think would happen if we discovered a signal today?

Natural radio emissions from the Andromeda galaxy, courtesy of SETI.

Tarter: It would change everything overnight. SETI wouldn’t have any funding problems anymore. People would be eager to see if there was information in the signal. But even if it was only a cosmic dial tone, with no obviously or instantaneously available information, we’d still learn some very fundamental facts.

We’ll learn that technologies can survive a long time. Unless technological civilizations have long lifetimes, we’re never going to succeed in detecting a signal. We have to be close enough in three-dimensional space, and we also have to overlap in time. In the 10-billion-year history of our galaxy, if civilizations only last for 100 years, there’s not going to be any overlap. If we get a signal, it means that technologies, on average, can last a long time.

I’m not saying we’re going to get extraterrestrial salvation, by any means. But I am saying we’ll learn that it’s possible to survive our technological adolescence. That’s where we’re stuck right now, and there are a lot of indications that we won’t make it out of this. A signal would make all the difference, would show that it’s possible. That somebody else did it.

To donate to the Allen Telescope Array and the Kepler worlds project, go to SETI.org.

Full disclosure: This reporter spent a summer at the SETI Institute.

Images: 1, 2 & 4) SETI Institute. 3) NASA.

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Reader Photo: Stunning Interactive Sky Image

27 Apr

This stunning 360 degree panorama of the night sky was stitched together from 37,000 images by a first-time astrophotographer.

Nick Risinger, a 28-year-old native of Seattle, trekked more than 60,000 miles around the western United States and South Africa to create the largest-ever true-color image of the stellar sphere. The final result is an interactive, zoomable sky map showing the full Milky Way and the stars, planets, galaxies and nebulae around it.

“The genesis of this was to educate and enlighten people about the natural beauty that is hidden, but surrounds us,” Risinger said.

The project began in March 2010, when Risinger and his brother took a suite of six professional-grade astronomical cameras to the desert in Nevada. By June, Risinger had quit his job as a marketing director for a countertop company to seek the darkest skies he could find.

Every night, Risinger and his father set up the cameras on a tripod that rotates with Earth. The cameras automatically took between 20 and 70 exposures each night in three different-color wavelengths. Previous professional sky surveys (including the Digitized Sky Survey of the 1980s, which is the source for the World Wide Telescope and Google Sky) shot only in red and blue. Including a third color filter gives the new survey a more real feeling, Risinger said.

“I wanted to create something that was a true representation of how we could see it, if it were 3,000 times brighter,” he said.

‘I wanted to create something that was a true representation of how we could see it, if it were 3,000 times brighter.’

Risinger sought out dry, dark places far from light-polluting civilization. Most of the northern half of the sky was shot from deserts in Arizona, Texas and northern California, although Risinger had one clear, frigid night in Colorado.

“It was January and we were hanging out in Telluride waiting for the weather to clear in Arizona or Texas,” he said. “Finally we realized the weather was hopeless down south, but it was perfectly clear where we were.” They drove an hour away, set up near a frozen lake, and sat in their car with the heat off for 12 hours as the temperature outside dropped to minus 6 degrees Fahrenheit.

“I would have loved to turn the car on for heat, but I was afraid the exhaust would condense on the equipment and make a shutter freeze or ice up the lenses,” Risinger said. “Certainly it was the coldest I’ve ever been, but I’ve still got all 10 toes and fingers.”

The southern hemisphere was captured in two trips to South Africa, not far from the site of the 11-meter Southern African Large Telescope. While there, Risinger and his father stayed with a sheep farmer who also watched the skies with his own amateur telescope.

Back in Seattle, Risinger used a combination of standard and customized astrophotography software to subtract noise from the cameras, stack the three colors on top of each other, link each picture to a spot on the sky and stitch the whole thing together. He taught himself most of the techniques using online tutorials.

Risinger plans to sell poster-sized prints of the image from his website and is looking for someone to buy his cameras, but otherwise has no plans to make money from his efforts. He wants to make the panorama available to museums and planetariums, or modify it for a classroom tool.

“When Hubble shoots something, it’s a very small piece of the larger puzzle. The purpose of this project is to show the big puzzle,” he said. “It’s the forest-for-the-trees kind of concept. Astronomers spend a lot of their time looking at small bugs on the bark. This is more appreciating the forest.”

Risinger sets up his cameras in Colorado.

Images: Nick Risinger

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Meet the future of the space program: Artificially-intelligent satellites [Video]

24 Mar
We're about to put smart robots in space. A new system in development at the University of Southampton in the UK could allow spacecraft to go beyond simply obeying commands, instead developing and reacting to knowledge about their missions. More »
 
 

Help Make Better Map of Global Light Pollution

22 Mar

You can help build the best global map of light pollution, the uniquely modern problem that has stolen starlight from most of the urbanized world.

From March 22 through April 6, the GLOBE at Night website will collect the public’s measurements of the night sky. Anyone can participate by comparing their local view of specific constellations with magnitude charts on the site. The event is in its sixth year, and organizers hope to surpass the 17,800 observations they collected in 2010.

“With half of the world’s population now living in cities, many urban dwellers have never experienced the wonderment of pristinely dark skies and maybe never will,” says the GLOBE at Night. “This loss, caused by light pollution, is a concern on many fronts: safety, energy conservation, cost, health and effects on wildlife, as well as our ability to view the stars.”

Baby sea turtles attracted by artificial light. (NIH)

Light pollution is caused by stray artificial light from sources that are too bright, poorly aimed or both. Similar to how sunlight makes the sky glow blue, artificial light scatters in the atmosphere to create a dull glow that obscures stars and celestial objects. Airborne pollutants exacerbate the problem.

Aside from the loss of stars from view, light pollution has more quantifiably dangerous sides. One model of Los Angeles suggests it destroys about 7 percent of smog-eating chemicals that build up in the dark, leading to a 5 percent jump in wheeze-inducing ozone pollution during the day. Other studies show artificial light can thwart animal migrations and negatively impact human health.

Satellites can assess artificial brightness from space, but the view is very different from the ground. By crowdsourcing measurements, GLOBE at Night aims to both create the most accurate map of how light pollution hides the stars and raise awareness of the problem. They also hope to spark a push for local artificial light ordinances, such as those passed in Flagstaff, Arizona, and other municipalities.

People living north of the equator can access the organization’s app to report night-sky conditions between March 22 and April 4. In the southern hemisphere, the window of opportunity is March 24 through April 6.

Images: 1) Historic and anticipated increases in artificial night sky brightness in the United States./NIH. 2) Worldwide measurements of light pollution submitted by 17,800 participants in 2010./GLOBE at Night.

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Arthur C. Clarke believed America’s smartest people were wasting their time on banking instead of the space program [Books]

18 Mar
There's a fascinating profile of Arthur C. Clarke over at the Sri Lanka Guardian, a newspaper in the land where Clarke spent the second half of his life. There are tons of insights into Clarke's life, writing and technological foresight. More »
 
 

Spacecraft Swings Into First Orbit Around Mercury

18 Mar

NASA’s Messenger spacecraft swung into position around Mercury Thursday night, making it the first spacecraft ever to orbit the innermost planet.

Engineers at the Johns Hopkins University Applied Physics Laboratory in Maryland, 96 million miles from Mercury, received the signal confirming that Messenger (MErcury Surface, Space ENvironment, GEochemistry and Ranging) had completed its final maneuver at 9:10 pm EDT.

To slow down enough to get caught in Mercury’s gravitational field, Messenger fired its main thruster for 15 minutes. The burn slowed the spacecraft by 1,929 mph and used up 31 percent of its original fuel supply.

After finishing the burn, Messenger rotated to face the Earth by 9:45 p.m., and started transmitting data. Engineering and operations teams confirmed the maneuver went according to plan.

The event marks the end of a 6½-year journey for Messenger, which has made 12 laps around the solar system, two flybys past Earth, one past Venus and three past Mercury since launching in August 2004.

Although engineers still need to do some analysis to figure out the spacecraft’s exact orbit, they expect Messenger to swoop around Mercury in a highly elliptical orbit once every 12 hours. It will dip within 120 miles of Mercury’s surface at its closest point, and go out to 9,320 miles at its farthest.

The orbit goes nearly pole-to-pole, offset by about 7 degrees. That slight tilt is to help get a handle on the planet’s gravitational field, said principal investigator Sean Solomon, a planetary scientist at the Carnegie Institution of Washington, in a press conference March 15.

Measurements of the gravitational field “will tell us something about Mercury’s composition, the size of the core and the structure of that core,” he said.

One of the mission’s main objectives is to figure out why Mercury’s core is so big compared to the cores of the other rocky planets. Another is to make high-resolution maps of the whole planet, some of which has still never been seen.

“Many on the science team have been involved from the very beginning,” Solomon said. “We are extremely excited to begin that mapping.”

Scientists also plan to search for water ice in craters at the poles which, despite Mercury’s proximity to the sun and scorching daytime temperatures, are stuck in eternal freezing shadow.

The spacecraft’s seven science instruments were turned off for orbit insertion, but they will reactivate March 23. The first orbital image, planned for March 29, will include some uncharted regions near Mercury’s south pole.

The science phase of the mission will begin April 4. The Messenger team will release data to the science community at six-month intervals, but will release images at least once a day throughout the mission, Solomon said.

“In addition to the global imaging we’ll be doing, we’ve targeted more than 2,000 areas for ultra-high-res with our narrow-angle camera. Many of them were not discovered until flybys,” he said. “We’ve got a long list.”

Images: 1) Artist’s conception of Messenger approaching Mercury. 2) The target area for Messenger’s first image from orbit, including never-before-seen terrain. (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

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The Moon Is Going to Be Huge on Saturday [Video]

16 Mar
On Saturday, for the first time since 1993, the Moon is going to be full at almost the exact same time it's closest to earth. So if you've got livestock you need to sacrifice, now's the time to do it! More »