Rings Detected Around Saturn’s Moon Rhea

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Saturn is known for the spectacular rings that circle the planet, and the Cassini spacecraft has been exploring Saturn’s rings, as well as its moons since 2004. And now Cassini has found evidence that there may be rings around one of Saturn’s moons, too: Rhea, the second largest moon in Saturn’s system. This is the first time rings may have been found around a moon. While no images yet have been taken of the rings (the picture here is an artist’s rendering) an extensive debris disk and at least one ring appear to have been detected by a suite of six instruments on Cassini specifically designed to study the atmospheres and particles around Saturn and its moons.

“Until now, only planets were known to have rings, but now Rhea seems to have some family ties to its ringed parent Saturn,” said Geraint Jones, a Cassini scientist and lead author on a paper that appears in the March 7 issue of the journal Science.

Rhea is about 1,500 kilometers (950 miles) in diameter. The apparent debris disk measures several thousand miles from end to end. The particles that make up the disk and any embedded rings probably range from the size of small pebbles to boulders. An additional dust cloud may extend up to 5,900 kilometers (3,000 miles) from the moon’s center, almost eight times the radius of Rhea.

Since the discovery, Cassini scientists have done simulations to determine if Rhea can maintain rings. The models show that Rhea’s gravity field, in combination with its orbit around Saturn, could allow rings that form to remain in place for a very long time. The discovery was a result of a Cassini close flyby of Rhea in November 2005.

One possible explanation for these rings is that they are remnants from an asteroid or comet collision in Rhea’s distant past. Such a collision may have pitched large quantities of gas and solid particles around Rhea. Once the gas dissipated, all that remained were the ring particles. Other moons of Saturn, such as Mimas, show evidence of a catastrophic collision that almost tore the moon apart.

“The diversity in our solar system never fails to amaze us,” said Candy Hansen, Cassini scientist and co-author on the paper. “Many years ago we thought Saturn was the only planet with rings. Now we may have a moon of Saturn that is a miniature version of its even more elaborately decorated parent.”

Original News Source: JPL/Cassini Press Release

Cassini To Fly Through Enceladus’ Plume March 12 (Video)

The venerable Cassini spacecraft will make an extremely close flyby of Saturn’s moon Enceladus, one of the most intriguing moons in the Saturn system. Earlier flybys by Cassini revealed a geyser-like plume of ice particles shooting up from Enceladus’ south pole region. This means there’s a water source on the moon, and of course, water on another body in our solar system is an intriguing mystery that we want to take a closer look at. And this look will be extremely close. At one point during the flyby, when Cassini is near the equator of Enceladus, the spacecraft will only be about 50 km from the moon’s surface.

Cassini will skim over moon on March 12, at 19:06 UT. When Cassini is near the south pole, however, the spacecraft will be about 200km from Enceladus’ surface– which is probably a good thing. Even a small particle hitting the spacecraft could do a lot of damage, and the scientists say Cassini should be flying well above where any ice particles should be.

Learn more about the flyby in this video that the Jet Propulsion Laboratory put together.

Also, this graphic shows the areas on Enceladus that will be observable to Cassini as it whizzes by. Cassini’s scientists are hoping this flyby will help us understand the interior of this moon and how extensive its water source may be.

Enceladus flyby overview.  Image Credit:  JPL Photojournal

Original News Source: Cassini website

Run, Don’t Walk, To Your Nearest Moon Base

An 'exoskeleton' made of fiberglass rods and springs, developed by MIT. Image courtesy of Christopher Carr.

Running is more efficient than walking for humans wearing spacesuits on the moon, according to a new study. A laboratory simulation of moonwalking found that pressurized spacesuits act as springs for our legs, and on the moon this effect is most pronounced during activity where the knee is bending at a greater angle, such as running. These findings may help NASA develop more efficient and comfortable spacesuits for future moon explorers, while also assisting research in prostheses for amputees. And who knows, maybe it could even promote the first lunar marathon run.

Because of the constriction of spacesuits and lower gravity, human movement is different on the moon than on Earth. This was evident during the Apollo missions where astronauts had a hard time bending over to pick up rocks or labored as they walked, but ran or bunny-hopped across the lunar surface with relative ease.

To simulate these conditions, researchers Christopher Carr and Dava Newman from MIT used an “exoskeleton” made of fiberglass rods and springs and placed them on the legs of a research subject. This exoskeleton was developed in large part by another MIT researcher, Dr. Hugh Herr in his study of prosthetics for amputees.

“We demonstrated that exoskeleton legs are similar to space suit legs, and that space suit legs act like springs due to the pressure of the space suit,” Carr told Universe Today. “Because of this, space suits support their own weight, but are hard to bend, making it difficult to carry out basic actions like picking up a tool from the ground.”

Carr is looking at ways to optimize the balance between stiffness and weight support to help the locomotive abilities for space-suited lunar astronauts. Less stiff spacesuits would enable easier ground access, but if they aren’t stiff enough, the suit will not support its own weight. Carr said the balance might be achieved with a change in the geometry of the space suit legs.

What else does this mean for future lunar exploration? During the Apollo missions there was a requirement of a walk-back constraint. Imagine a circle with an astronaut at the center, with the radius of the circle determined by how far you could walk while using only an emergency oxygen supply. This radius would specify how far away an astronaut could travel from their ‘base’, so that if a failure occurred he would be able to return safely. Now that we know running is more efficient than walking, said Carr, we should be able to base this constraint on running, allowing astronauts to travel further from their ‘base’, whether that base is their main habitat, or a pressurized rover.

Carr said he was somewhat surprised by their findings using the exoskeleton.

“I had not expected the forces imposed on the body by the exoskeleton to be so similar to the space suit knee joint,” he said.

They also used a simulated lunar gravity (1/6th of Earth’s) where the research subject wearing the exoskeleton was supported by cords attached to the ceiling by springs. “In this case, the subjects were even more efficient using an exoskeleton than walking or running without the exoskeleton,” said Carr. “We knew this was a possibility, but the proof is in the pudding.”

From this research it’s interesting to speculate about future athletic endeavors on the Moon. Running might be the sport of choice for lunar inhabitants, and the possibilities abound for lunar basketball. “Lower gravity might mean big jumps,” said Carr. “Even though our muscles will contract really fast, and thus will not be very efficient, we should be able to jump with a higher vertical velocity on the moon, maybe 30-50% faster than on Earth based on prior studies. Because gravity is 1/6 of Earth, that velocity will allow us to jump many times higher. We had better design those lunar habitats with high ceilings.”

Journal Reference: Science Direct

The Ultimate Fund-Raising Scheme: Transmit Adverts To Aliens

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OK, so there have been some strange things going on between us Earthlings and aliens lately. The deep-space Pioneer and Voyager probes carried images and artefacts of our culture into the cosmos decades ago. This plan has now been upstaged by the Deep Space Network transmitting a Beatles tune in the direction of the star Polaris. Both are different methods in an attempt to achieve the same thing – to contact alien civilizations. Extraterrestrials might even be trying to communicate with us by playing around with stars or blasting neutrinos at us

But, in the next episode of this epic saga, as the human race feels more and more alone in a seemingly lifeless, but expanding universe… [breakthis programme will be continued after a message from our sponsors]

Advertising is everywhere. It comes in many shapes and sizes, and in many forms. I just deleted four pieces of spam in my email account (one trying to sell me non-prescription pain killers, one notifying me that I have won the Russian lotto and another two with subjects I’d rather not repeat), I can hear an ad on the radio chatter (something about double-glazed windows), on my desk I can count ten magazine ads, newspaper classified ads, business cards and logos, all set out to do pretty much the same thing: to sell a product and, ultimately, to make money. Advertising is so embedded into our commercial society, it can be difficult to work out what is advertising and what isn’t.

Now it seems there is another kind of advertising on the horizon: Space Spam.

As UK physics and astronomy researchers have experienced recently, the problem with scientific research is that it mainly depends on government funding. Government funding comes and goes and can depend on who is in power and who isn’t. To avoid this, many researchers leave academia in search of better pay in industry. There is nothing wrong with this choice, but often academic institutions and universities lose their top minds to better financial conditions elsewhere.

In an attempt to save the beleaguered astronomy community in the UK, astronomers have come up with an intriguing idea. To rescue the world famous Jodrell Bank Observatory in Cheshire, astronomers intend to transmit adverts into space. This is truly the final frontier for terrestrial advertising, but is it possible that British scientists have finally lost their marbles? How can we expect alien races to pay attention to our attempts at selling them Nacho Cheese Doritos? If they did buy our products, I wouldn’t want to be in charge of the shipping department…

But there is a very serious reason for this off-beat plan. The UK is currently undergoing a funding crisis as the main funding body for UK physics and astronomy struggles to fill a £80 million ($160 million) hole in their finances. No help has been offered by the British government. This new fund-raising scheme is already attracting a lot of attention. The snack manufacturer Doritos has stepped in, donating an undisclosed sum in exchange for transmitting their ad. Many more companies are expected to follow suit. The publicity from helping out struggling observatories seems to be enough for big companies wanting to get involved (after all, they won’t be expecting extraterrestrial orders for at least 84 years).
The incoherent scatter radar facility (EISCAT) on Svalbard in 2002 (credit: Ian O'Neill)
The signal will be sent to the Ursa Major constellation some 42 light years away by the European Incoherent Scatter Radar System (EISCAT) in Svalbard, located in the High Arctic. EISCAT is more commonly used to measure emissions from the aurora and ionospheric dynamics. It can also be used in conjunction with other EISCAT installations in Sweden and mainland Norway to track the velocity and composition of the solar wind. Now, it seems, the powerful radar transmitter will be used to shoot commercials into space.

The first transmission will be 30 seconds long and members of the public will be invited to participate. TV advertising will also be aired in support of the project. If anyone thought UK researchers were going to stay quiet and accept the latest round of financial turmoil, they’d be wrong. Scientists and the public, backed up by advertising revenue, are about to make a very big noise.

If the Beatles tune didn’t agitate the aliens, an enforced ad break probably will, let’s just hope they are sympathetic to the UK funding crisis (and want to make a donation).

Source: Doritos.co.uk, Jodrell Bank Observatory press release

Carnival of Space #44

This week, the Carnival of Space returns to Bad Astronomy with a Mars-themed series of stories. Fear the angry Red Planet!

Click here to read the Carnival of Space #44

And if you’re interested in looking back, here’s an archive to all the past carnivals of space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let me know if you can be a host, and I’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

Traffic Jam at the Space Station

Space traffic control will be needed at the International Space Station as a busy timeframe of missions and resupply flights continue for our home port in space. In a choreographed ballet of spaceships, ESA’s first Automated Transfer Vehicle (ATV) resupply ship and NASA’s Space Shuttle Endeavour are scheduled to liftoff on March 9 and 11, respectively, to dock with the ISS, while a third – Russia’s Soyuz – is due to arrive early in April. The heavy traffic comes just a few weeks after Space Shuttle Atlantis left the ISS on February 18, delivering the Columbus science lab to the station. With Endeavour scheduled to be docked to the ISS from March 13 – 24, the ATV must patiently wait in a “parking orbit,” travelling in a holding pattern below the station, and will then dock after the shuttle leaves.

As of now, everything is “go” for all three flights. Endeavour will ferry Japan’s Kibo science lab to the ISS, along with the Canadian Space Agency’s two-armed robotic system called Dextre. STS-123 is commanded by Dominic Gorie with Greg Johnson serving as pilot. The crew also includes Mission Specialists Rick Linnehan, Robert Behnken, Mike Foreman, Garrett Reisman and Japanese astronaut Takao Doi. Reisman will stay aboard the station, trading places with ESA astronaut Léopold Eyharts, who has been on board since Atlantis’ February mission to the ISS.

But in the meantime, the ATV will be waiting in the wings to deliver its cache of supplies to the station. “After launch, we will have an opportunity to show and demonstrate to our ISS partners exactly what the ATV is capable of doing,” said Alberto Novelli, ESA’s Mission Director for the ATV. “And we can place ATV in a holding orbit for an extended period, if necessary, before doing the final, actual docking,”.

Space Traffic Control.  Image Credit:  ESA
The ATV is scheduled to dock on March 29. However, if there are any slips or technical issues to delay the ATV’s docking, there are only four subsequent days on which the actual docking can take place. One limitation causing this is illumination conditions: astronauts on board the station must not be blinded by sunlight while monitoring the approaching vehicle’s progress.

Another limitation is caused by more traffic: Russia’s Progress M-63, docked since February 7, will undock on April 7 and a new Soyuz arrival and docking is scheduled for April 10. Additional limitations on the ATV docking window could come about if Endeavour’s launch is delayed or if its docked phase extends past March 27. For example, last month, Atlantis’ docked phase was extended by one day to facilitate the installation of Columbus.

“It’s an extraordinary time. While we face a tight window, the intense activity at the ISS these weeks – with European, American, Russian, Canadian and Japanese payloads or vessels in flight – highlights the fantastic international character of the Station,” said Bob Chesson, ESA’s manager for Human Spaceflight Operations.

Check out the ATV blog to follow the mission live, and NASA’s STS-123 launch blog.

Original News Source: ESA Press Release

Origins of the Earth’s Atmospheric “Hiss” Energizing Van Allen Belt Particles Revealed

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Scientists working at the University of California, Los Angeles (UCLA) have identified the origin behind the upper atmospheric “hiss” that energizes the high-energy particles bouncing around inside Earth’s radioactive Van Allen Belts. This is significant, as this has been a very long wait for answers to the origin of this low-frequency radio wave emission… after 40 years of looking, we may now have an answer…

The Van Allen Belts surrounding Earth can be a terrifying place for spacecraft and astronauts. Occupying a volume 200 km above the surface and can extend as far as seven Earth radii (over 44,000 km). These volumes of highly energetic particles are trapped by the Earth’s magnetosphere, bouncing electrons and protons back and forth in their magnetic prison. The Van Allen Belts are variable and closely related to solar activity. As the solar wind hits the Earth’s magnetosphere, solar wind particles will fall into the polar cusp regions, entering the atmosphere and creating aurorae in Northern and Southern Polar regions (Aurora Borealis and Aurora Australis respectively). However, some particles are fed into the magnetosphere and become trapped between the onion skin-like layers of magnetic field lines and cannot escape.
The Van Allen Belts surrounding Earth (source: astronomycafe.net)
This is how the Van Allen Belts are supplied, and the population of protons and electrons are expected to increase and become more energetic during solar storms. Although we know a lot about these regions, very little is known how the trapped electrons and protons are energized so much that they can penetrate lead up to 1 mm deep. This has obvious design implications for the thousands of satellites orbiting the Earth, and poses a serious health risk to astronauts spending long periods in space.

In new research published in Nature today, the UCLA research group believe they have found the origin of upper atmospheric “hiss”. The hiss has radio wave frequencies and has been observed since early missions into space in the 1960s. Thought to originate from magnetic interactions in the magnetosphere itself, or even from intense lightning storm emissions into the upper atmosphere, definitive proof for the source of this strange phenomenon was proving very elusive. Putting classical ideas to one side, Jacob Bortnik’s work focuses on a totally different form of electromagnetic wave called “chorus”. This wave was thought to have no connection with radio hiss, but Bortnik proves that chorus waves, travelling many thousands of kilometres, can evolve into the hiss which characterizes the Van Allen Belts.

Here, we show that a different wave type, called chorus, can propagate into the plasmasphere from tens of thousands of kilometers away and evolve into hiss. Our new model naturally accounts for the observed frequency band of hiss, its incoherent nature, its day-night asymmetry in intensity, its association with solar activity and its spatial distribution. The connection between chorus and hiss is very interesting because chorus is instrumental in the formation of high-energy electrons outside the plasmasphere, while hiss depletes these electrons at lower equatorial altitudes.” – Jacob Bortnik.

The UCLA group were actually not researching the atmospheric hiss, but were working on chorus waves – that typically propagate outside the plasmasphere – and realized they could evolve into the “hiss” responsible for particle energization in the Van Allen Belts.

This research has massive consequences for the prediction of space weather. The conditions of the space between the Sun and Earth is very important when predicting the onset of a solar storm, but the reaction of the Earth’s upper atmosphere is critical when understanding how potentially damaging particles are energized to such a large extent.

Source: Physorg.com

Extreme Observations of the Aurora in a Land of Polar Bears and Frostbite – Images of Research in the Freezer

Solar-terrestrial physics observations are about to get even more exciting. The University Centre on Svalbard (UNIS) has completed the construction of a brand new observatory, The Kjell Henriksen Observatory (KHO), providing researchers with a shiny-new ringside seat to observe a dazzling atmospheric phenomena, the Aurora Borealis (a.k.a. the Northern Lights). It is probably one of the most extreme places on the planet, with temperatures dropping below minus 35 degree Celsius (-31F) and where humans are no longer at the top of the food chain, working on Svalbard can be challenging, but very rewarding. Witnessing the aurora erupt overhead is an awe inspiring sight, to observe and research this reaction between the solar wind and upper atmosphere is a chance in a lifetime. What’s more… I’ve been there…


Svalbard is a strange but magical place. Found high in the Arctic Circle, half-way between Norway and the North Pole, the archipelago attracts international attention for its untouched landscape and unique location. Famed as the magical destination for a series of novels (Philip Pullman’s “His Dark Materials” trilogy) and a blockbuster movie (“The Golden Compass“), the main island of Spitsbergen plays host to some of the most dramatic scenery on Earth. The panserbjørne may not be armour-plated, but there are bears nonetheless, insuring humans take special precautions.
At the town limit of Longyearbyen, rifle loading time (credit: Ian O'Neill)
Although life can be tough up there – temperatures plummeting lower than minus 35 degrees Celsius; over four months of Arctic night; the constant need to carry a rifle when travelling beyond settlement limits – people live very comfortably, mainly working in coal mine towns, for the local tourism industry or studying biology, physics or technology in the worlds most northerly university called “UNIS”.

I had the amazing fortune to live there for five months, in the spring of 2002, as part of an exchange program between the University of Wales, Aberystwyth (UK) and the University of Tromsø (Norway). A group of five of us British guys set off to the Arctic to study the physics behind the Earth’s magnetosphere, the solar wind and the aurora.
The town of Longyearbyen.
Nothing can really prepare you for a trip to this extraordinary place. Trying to study in 24 hour Arctic night is hard (dragging yourself out of bed is a mission in itself!), but it makes for magnificent viewing of the Aurora Borealis on an inky-black backdrop of the night sky. Actually, it was the 24 hour day light that affected me the most. As the Sun slowly crept above the frozen horizon during March 2002, the darkness was sadly lost and the Northern Lights were never to be seen again.

I remember one night in particular, probably early February 2002. As part of our study for the “Upper Polar Atmosphere” course, we had to carry out some actual space research. The task was to track the effects of a Coronal Mass Ejection (CME) as it travelled from the Sun and impacted the Earth’s atmosphere. A seemingly massive task, but an exciting one – after all we were sitting below the lightshow very few people were able to experience, and we’d been set the goal of explaining how this amazing phenomenon actually works! That freezing February night, we had all been driven to the “Auroral Station” situated just outside Longyearbyen, the capital city (I say “city”, but only 2000 people live there) of Svalbard.
The old Auroral Station (credit: Ian O'Neill)
Resembling part-laboratory/part-shed, the Auroral Station (known as “Nordylysstatsjonen”) was a strange fixture to see standing in the snow. On entering we were faced with an observatory crammed with computers and cameras. This was the home of the “All Sky Camera” (ASC), a basic wide-angled camera looking up into the sky. On active nights, the ASC could take in a 360° view, from horizon to zenith, watching the auroral lightshow erupt overhead, watching the effects of solar particles impact the Earths upper atmosphere, and emitting light.

Stills from the ASC, from left to right, as an aurora develops (credit: Gareth Thomas/Ian O'Neill)

Unfortunately, the aurora didn’t show after several hours of waiting, looking through the bubble-shaped windows in the roof of the station.

In those long moments of waiting, it was very obvious that the days of observing the night sky in this little observation post were numbered. To the south-eastern skies, a creeping glow of street lights were of constant annoyance to the station scientists – even a town as tiny as Longyearbyen was putting out enough light pollution to interfere with the sensitive instruments. The outlook wasn’t good, the town was expanding and the pollution could only get worse.

Kjell Henriksen Observatory
The answer to this problem was obvious back then… the station would have to be moved, away from the excess light pollution. Exactly six years later, the solution has been realized.
The new Kjell Henriksen Observatory opened in February 2008 (Credit: Olli Jokiaho/UNIS)
On February 20th, 2008, the new state of the art observatory was completed. Situated 6 km (3.7 miles) up the fjord from the original location, the Kjell Henriksen Observatory is now proudly positioned 500 meters up a mountain overlooking a long valley called Adventdalen.

The new observatory was opened by Norway’s Minister for Research and Higher Education, Tora Aasland, announcing:

The International Polar Year 2007-2008 is a huge international research effort of great importance to the northern region, as well as to global challenges. When the new observatory was planned, the goal was to have it ready for the Polar Year. I am very pleased that this goal was reached” – Tora Aasland

The new installation houses an impressive suite of instruments. In all over 15 optical and non-optical instruments are based here, operated by a range of international collaborators, observing mid- to upper-atmospheric phenomena. Even some of the most advanced all-sky cameras are now up and running during this “auroral season”.

Although the Northern Lights did not put on a show for the grand opening, and snow drizzled on the event, I hope the new observatory will be as successful as its predecessor and help to entice many more students (like myself, six years ago) into a research career focused on the Sun and its intrinsic relationship with the Earth.

For full details on the opening of the Kjell Henriksen Observatory, visit the UNIS news pages.

Source: UNIS, The Kjell Henriksen Observatory

Observing the Atmospheres of Venus and Mars Leak into Space (Video)

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It turns out that Venus and Mars aren’t actually that different after all. Although Mars has very little atmosphere to speak of and Venus has a stifling, thick, poisonous one, they have one thing in common: the Sun. The solar wind constantly batters the Solar System’s planets, stripping their atmospheres into space. Is it possible that Mars may once have had a thick atmosphere like Venus’, but has long since leaked away?

The twin ESA spacecraft, Venus Express and Mars Express, have very similar instruments on board and are currently orbiting the two planets. Mars Express arrived on December 25th 2003 and Venus Express arrived on April 11th 2006. Venus Express was intended as a “copy” of the older Mars Express design, but some upgrades were required. Primarily, as Venus is two times closer to the Sun, Venus Express needed better protection from solar radiation. There will also be an increase in ionizing high-energy particles hitting the orbiter, so this had to be taken into account.

Apart from a few minor upgrades, the twin Express missions are able to carry out the same observations on both planets, providing ESA scientists with a unique opportunity to compare results of both spacecraft. In fact, for the first time ever, researchers are able to carry out comparative planetology of two planets with two orbiting spacecraft as they are carrying similar instrumentation.

One such instrument is the Analyser of Space Plasmas and Energetic Atoms (ASPERA) that can be found on both spacecraft. ASPERA has detected atmospheric particles leaking into space as the solar wind hits the planetary atmospheres. Both Mars and Venus, despite their difference in orbits and size, exhibit similar patterns of particle loss. As the planets have no uniform magnetic field surrounding the atmosphere, atmospheric particles are easily swept away. In the case of the Earth, our atmosphere is protected by a strong magnetosphere blanketing us from the ferocious solar wind.

Ultimately ESA scientists hope to analyse the rate of particle loss from Mars and Venus so a better picture of planetary evolution can be arrived at. It is possible that the solar wind may be responsible for the very thin Martian atmosphere. Mars is a tiny planet (only half the size of Earth); whereas Venus is often considered to be Earth’s “sister” as it is approximately the same size. Perhaps the low Mars gravity allowed a higher rate of atmospheric loss than Venus.

What ever the conclusion, mission scientists have a lot of work to do. The results will not only help us understand the development of Mars and Venus, it will also aid our understanding about how the Earth is evolving and may give us some clues to the future.

Video: The strong interaction of the solar wind with the atmosphere of Venus (ESA)

Source: ESA

Do Advanced Civilizations Communicate with Neutrinos?

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It’s one of the biggest questions in all humanity: are we alone in the Universe? Either way, the answer is significant. And so, scientists are searching for intelligence out there. Huge arrays of radio telescopes, like the Allen Array scan the skies for radio broadcasts. And researchers have also proposed that aliens might be using lasers to communicate with us. A Russian researcher is proposing another way that aliens might be communicating with us – with neutrinos.

To borrow a quote from the Hitchhiker’s Guide to the Galaxy, “Space is big. You just won’t believe how vastly, hugely, mind- bogglingly big it is.” When you’re attempting to communicate across the vast distances of space, you need huge amounts of energy. Just look at a star, even though it’s generating an incomprehensible amount of energy every second, the brightness drops dramatically with distance.

Instead of broadcasting in all directions, the other strategy is to focus your communications towards a specific location. A targeted beam of radio waves or laser light towards another star still requires an enormous amount of energy, but it’s less.

To save energy, alien civilizations might not be using radio or optical light at all, they might be communicating in a completely different way, with neutrinos.

Researcher Z. K. Silagadze at the Budker Institute of Nuclear Physics and Novosibirsk State University recently posted this idea to the Arxiv pre-press mailing list. His article is called SETI and Muon Collider.

It might sound like science fiction, but scientists are starting to understand how to generate beams of neutrinos – by creating beams of muons. Beams of these unstable particles can be generated in large particle accelerators. The muon beam decays quickly into a focused beam of neutrinos that can travel for light years and still remain remarkably coherent. A beam fired at relatively nearby star Tau Ceti, 12 light-years away, would open up to about 600 astronomical units across – enough to bathe the whole system in neutrinos that could be tracked back to a specific source star.

Finding neutrinos here on Earth is difficult. We’ve got an incredible amount of neutrinos stream towards us from the Sun. In fact, you’ve got billions of neutrinos passing through your body every second and you never feel them because never interact. It takes a huge vat of water, protected underground from other radiation and a suite of sensitive detectors. And even then, they only turn up a few thousand neutrinos a year.

In fact, a neutrino can pass through light-years of pure lead and not even notice.

But there are some advantages. Neutrino detectors are omnidirectional – they don’t have to be targeted in a specific direction to “tune in” a signal coming from a star. If the stream of neutrinos is passing through the Earth, we should be able to detect it, and then track back the source after the fact.

Neutrino detectors are also sensitive to many different energy levels. They don’t have to scan specific frequencies, they can detect high energy neutrinos as easily as low-energy ones.

According to Silagadze, the newly developed IceCube neutrino observatory being built in Antarctica should have the sensitivity to spot neutrinos generated on purpose by alien civilizations – whether they’re targeting us specifically, or we’re just overhearing their conversations.

It has been suggested that advanced civilizations might deliberately choose neutrinos for communications because it shuts out the very young, and not mature civilizations from the galactic conversation.

But give us a few years, and we’ll be listening.

Original Source: Arxiv