NRAO: Milky Way Explorer Software Tours the Solar System

NRAO's Milky Way Explorer Tours the Solar System

Imagine seeing the Sun, planets, and a myriad other objects in our Solar System as you have never seen them before, in invisible radio light!

That is the experience you will get through the National Radio Astronomy Observatory's (NRAO) newly released Solar System installment of its popular Milky Way Explorer, an online tour of our interstellar neighbourhood guided by the actual astronomers who explore it using radio waves.

Through an entertaining and informative series of videos, NRAO's Science Visualization Team presents multimedia-rich tours of the radio Sun as well as many of the planets, moons, and asteroids that orbit it.

At each stop along the way, planetary radio astronomers reveal the new science and exciting details we have learned about our Solar System neighbours through the use of radio telescopes.

Unlike familiar optical telescopes, which can only study objects illuminated by our Sun and other stars, radio telescopes can see the otherwise invisible cold, dark features in space.

This includes the faint radio light that is naturally emitted by the molecules and chemicals that make up the atmospheres of planets and certain moons in our Solar System.

Radio dishes, when paired with powerful radar transmitters on Earth, can also reveal hidden landscapes, such as the Moon's dust-layered surface and Venus's alien features shrouded behind its thick clouds.

The Milky Way Explorer, which was launched in 2013, also includes dozens more videos showcasing the diverse radio astronomy studies of our spiral island of stars, stellar nurseries, and dark matter.

A third set of interviews and animations is scheduled for 2015 to share more radio astronomy discoveries made inside our Galaxy and among the nearest neighboring galaxies of our Universe.

Introduce your children to the Wonders of Space: The Solar System Song

Introduce your children to Outer Space: "We are the Planets," The Solar System Song by StoryBots

NRAO Very Long Baseline Array takes radio image of Voyager 1

Credit: NRAO/AUI/NSF

The image above is a radio image of Voyager 1.

It was taken from NRAO's Very Long Baseline Array (VLBA), which is a collection of 10 radio telescopes scattered from Hawaii to the Virgin Islands.

It captures the faint radio signal of the distant probe. That pale blue dot is the most distant object made by humans.

The radio strength of Voyager 1 is about 23 watts. That signal is directed toward Earth, but Voyager is about 15 billion kilometers from Earth, so by the time the probe's signal reaches us its power is less than an attowatt, or a billionth of a billionth of a watt.

That faint signal is the only information we have from a probe that left our planet 36 years ago.

Of course it isn't enough to simply detect the signal from Voyager 1, we must receive the signal the way you might receive a radio signal, or a mobile phone call.

That requires even greater sensitivity, which is why it requires large radio telescopes to communicate with Voyager.

We have to be able to hear Voyager's faint messages, and we have to send radio responses that are powerful enough and focused enough for Voyager to receive.

Voyager 1 has, arguably, entered interstellar space, but has only begun its journey to the edge of our solar system.

It will eventually leave our Sun's grasp, since it has enough speed to escape the Sun's gravity, but it will become silent long before then.

In another 5 – 10 years it won't have enough power to operate its instruments.

That's part of what makes this current milestone so significant. Voyager 1 has not only reached interstellar space, but it has communicated the fact to us and we have gained knowledge and insight from it.

That pale blue dot, a radio blip in a radio dark sky, is a part of us.

It is an 800 kg, car sized, nuclear-powered computer that we launched into space to explore the solar system.

Our curiosity and quest for knowledge drove us to create it, and our developing intelligence allowed us to build it.

After a 36 year journey towards the harshness of interstellar space, it continues to communicate with its creators.

Looking out from one pale blue dot towards another one.

(Taken from an article by Brian Koberlein)

Evidence of water ice clouds found outside solar system

Credit: A. Fujii

A team of scientists led by Carnegie's Jacqueline Faherty has discovered the first evidence of water ice clouds on an object outside of our own Solar System.

Water ice clouds exist on our own gas giant planets, Jupiter, Saturn, Uranus, and Neptune, but have not been seen outside of the planets orbiting our Sun until now.

Their findings are published by The Astrophysical Journal Letters.

At the Las Campanas Observatory in Chile, Faherty, along with a team including Carnegie's Andrew Monson, used the FourStar near infrared camera to detect the coldest brown dwarf ever characterised.

Their findings are the result of 151 images taken over three nights and combined.

The object, named WISE J085510.83-071442.5, or W0855, was first seen by NASA's Wide-Field Infrared Explorer mission and published earlier this year. But it was not known if it could be detected by Earth-based facilities.

"This was a battle at the telescope to get the detection," said Faherty.

Chris Tinney, an Astronomer at the Australian Centre for Astrobiology, UNSW Australia and co-author on the result stated: "This is a great result. This object is so faint and it's exciting to be the first people to detect it with a telescope on the ground."

Brown dwarfs aren't quite very small stars, but they aren't quite giant planets either.

They are too small to sustain the hydrogen fusion process that fuels stars.

Their temperatures can range from nearly as hot as a star to as cool as a planet, and their masses also range between star-like and giant planet-like.

They are of particular interest to scientists because they offer clues to star-formation processes. They also overlap with the temperatures of planets, but are much easier to study since they are commonly found in isolation.


A team of scientists led by Carnegie's Jacqueline Faherty has discovered the first evidence of water ice clouds on an object outside of our own Solar System. 

Water ice clouds exist on our own gas giant planets, Jupiter, Saturn, Uranus, and Neptune, but have not been seen outside of the planets orbiting our Sun until now.

Their findings are published by The Astrophysical Journal Letters. 

Credit: Produced and directed by Brian Patrick Abbott. Written by Jacqueline K. Faherty

W0855 is the fourth-closest system to our own Sun, practically a next-door neighbour in astronomical distances.

A comparison of the team's near-infrared images of W0855 with models for predicting the atmospheric content of brown dwarfs showed evidence of frozen clouds of sulphide and water.

"Ice clouds are predicted to be very important in the atmospheres of planets beyond our Solar System, but they've never been observed outside of it before now," Faherty said.

Sun sends more 'shock waves' to Voyager 1 - Video

Credit: NASA/JPL-Caltech

NASA's Voyager 1 spacecraft has experienced a new "shock wave" from the sun as it sails through interstellar space.

Such waves are what led scientists to the conclusion, in the fall of 2013, that Voyager had indeed left our sun's bubble, entering a new frontier.

"Normally, interstellar space is like a quiet lake," said Ed Stone of the California Institute of Technology in Pasadena, California, the mission's project scientist since 1972.

"But when our sun has a burst, it sends a shock wave outward that reaches Voyager about a year later. The wave causes the plasma surrounding the spacecraft to sing."

Data from this newest tsunami wave generated by our sun confirm that Voyager is in interstellar space, a region between the stars filled with a thin soup of charged particles, also known as plasma.

The mission has not left the solar system, it has yet to reach a final halo of comets surrounding our sun, but it broke through the wind-blown bubble, or heliosphere, encasing our sun.

Voyager is the farthest human-made probe from Earth, and the first to enter the vast sea between stars.

"All is not quiet around Voyager," said Don Gurnett of the University of Iowa, Iowa City, the principal investigator of the plasma wave instrument on Voyager, which collected the definitive evidence that Voyager 1 had left the sun's heliosphere.

"We're excited to analyze these new data. So far, we can say that it confirms we are in interstellar space."




The first two tsunami waves to reach Voyager 1 caused surrounding ionized matter to ring like a bell at frequencies expected in interstellar space. 

The third tsunami caused similar ringing, confirming that Voyager 1 continues it journey into interstellar space. 

Image Credit: NASA's Voyager 1 spacecraft

Our sun goes through periods of increased activity, where it explosively ejects material from its surface, flinging it outward. These events, called coronal mass ejections, generate shock, or pressure, waves.

Three such waves have reached Voyager 1 since it entered interstellar space in 2012. The first was too small to be noticed when it occurred and was only discovered later, but the second was clearly registered by the spacecraft's cosmic ray instrument in March of 2013.

Cosmic rays are energetic charged particles that come from nearby stars in the Milky Way galaxy. The sun's shock waves push these particles around like buoys in a tsunami.

Data from the cosmic ray instrument tell researchers that a shock wave from the sun has hit.

Meanwhile, another instrument on Voyager registers the shock waves, too. The plasma wave instrument can detect oscillations of the plasma electrons.

"The tsunami wave rings the plasma like a bell," said Stone. "While the plasma wave instrument lets us measure the frequency of this ringing, the cosmic ray instrument reveals what struck the bell—the shock wave from the sun."

This ringing of the plasma bell is what led to the key evidence showing Voyager had entered interstellar space. Because denser plasma oscillates faster, the team was able to figure out the density of the plasma.

In 2013, thanks to the second tsunami wave, the team acquired evidence that Voyager had been flying for more than a year through plasma that was 40 times denser than measured before, a telltale indicator of interstellar space.

Why is it denser out there? The sun's winds blow a bubble around it, pushing out against denser matter from other stars.

Now, the team has new readings from a third wave from the sun, first registered in March of this year.

These data show that the density of the plasma is similar to what was measured previously, confirming the spacecraft is in interstellar space.

Thanks to our sun's rumblings, Voyager has the opportunity to listen to the singing of interstellar space, an otherwise silent place.

Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn.

Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft and is expected to enter interstellar space in a few years.

SEDNA: Dwarf Planet on the outer regions of Solar System

Sedna is a dwarf planet on the far outer reaches of the solar system.

Credit: NASA

Sedna is a dwarf planet that is one of the most distant bodies found in our solar system.

The object's closest approach to the sun is far greater than Pluto's distance away from Earth, at a spot where the sun is so tiny, according to NASA, that you could blot it out with a pin.

At 8 billion miles (12.8 billion kilometers) away, it's hard to figure out things such as surface features, but one thing astronomers have been able to identify is Sedna's distinct reddish colour.

Mike Brown

In 2004, it was described as the second-reddest object in our solar system, after Mars.

Sedna was discovered by a team led by Mike Brown, an astronomer at the California Institute of Technology.

The discovery of Sedna and other objects similar to it was a large impetus behind demoting Pluto from planetary status in 2006.

Image of Sedna, taken by Hubble Space Telescope

Discovery and basic statistics
Brown's team found Sedna in 2003 as part of a larger survey of the solar system that began in 2001.

Using the Samuel Oschin Telescope at the Palomar Observatory (east of San Diego) as well as Palomar's Quasar Equatorial Survey Team (QUEST) camera, the astronomers would take pictures of a tiny spot in the sky, one per hour for three hours, and see if they could find something that moved, Brown said in an explanation page about the discovery.

"The many billions of stars and galaxies visible in the sky appear stationary, while satellites, planets, asteroids, and comets appear to move. Objects in the inner Oort Cloud are extremely distant and so move extremely slowly," he said.

The Oort Cloud expands from a narrow belt on its inner edge
 into a large sphere farther from the Sun.

The Oort Cloud is a theorized area far in the solar system that is supposed to contain billions of icy objects that, if they receive a gravitational push toward the sun and warm up, turn into comets as the sun's energy melts the ice.

Sedna, however, was much bigger than a comet. Estimates for Sedna's size vary, but it is believed to be slightly smaller than the size of Pluto (1,400 miles or 2,250 kilometers in diameter).

Sedna takes some time to orbit the sun, not only because of its vast distance but also because its orbit is so elliptical or oval-shaped.

The dwarf planet takes roughly 10,000 years to complete one circuit around the sun. At the time of its discovery, it was at one of the closest points of its orbit to the sun, making it easier to spot.

Credit: Nasa

More Information: An explanation page about the SEDNA discovery

Steve Thomas: Art Deco Posters of the Planets

Frank Sinatra's "FLY ME TO THE MOON" has been brought to life in a set of Space posters depicting travel around the Solar System, in the Art deco style of the 1930's.

The posters by Steve Thomas mimic those from the halcyon days of travel, with each one imagining and depicting he wonders of the known planets.

Russian Cosmonaut Alexander Misurkin: Humankind should explore the Solar System and beyond

Alexander Misurkin

Alexander Misurkin. Image courtesy RIA Novosti and Ramil Sitdikov.

Russian astronaut Alexander Misurkin thinks humankind should not stop at the exploration of near-Earth space but rather go further in the universe, the explorer told RIA Novosti Tuesday.

"I think, we shouldn't limit ourselves to exploring the Earth's orbit. I, personally, would be interested in going to the outer space, exploring the asteroids, the Moon, and Mars. It's a natural development for me, we have no right to stop at the orbit of our planet," Misurkin said.

Misurkin was part of the international space station crew coming back to Earth in September 2013.

The astronauts carried out 45 scientific research tasks in the 166 days they spent on board of the station.

Fyodor Yurchikhin

Alexander Misurkin and Fyodor Yurchikhin went into open space working there for 7,5 hours hitting record time for a Russian-made spacesuit.

"Coming back to the orbit is a logical development, because astronaut training is extremely expensive for just one flight," he said expressing his willingness to participate in another space expedition.

Misurkin thinks that US sanctions on Russia can deal a heavy blow to space cooperation.

"I am more than sure that great achievements in space require collaborative work, there is no alternative here. I really hope this doesn't happen and we continue cooperation all the while involving more and more countries in it," the astronaut said.

Solar System: Sun, Earth and Mars Align

Mars takes the celestial stage Tuesday night (April 8) when it lines up with the Earth and our Sun, in a kind of cosmic preview to the Red Planet's closest approach to Earth during a total lunar eclipse later this month.

The alignment between Mars, the Earth and the sun is called "opposition" because Mars and the sun are opposite to each other in our sky.

Opposition and the date of closest encounter are slightly different because Earth and Mars are not in perfectly circular orbits.

Oppositions between Earth and Mars happen about every 26 months because the planets are relatively close to one another.

NASA and other agencies often take advantage of these close approaches to send spacecraft that way.

A recent example is NASA's Mars Atmosphere and Volatile Evolution probe (MAVEN), which launched in November 2013 and will arrive this September.

India's space agency, ISRO's first Mars orbiter will also arrive at the Red Planet in September after its own launch last year.

The opposition of Mars comes just seven days ahead of the planet's closest approach to Earth on the night of April 14.

The Red Planet and Earth are converging ever closer to their cosmic encounter at a rate of about 186 miles (300 kilometers) a minute, according to a NASA skywatching advisory.

On April 14, Mars and Earth will be only 57 million miles (92 million kilometers) apart. This is a bit more than half the distance between Earth and the sun, which is about 93 million miles (150 million km).

By coincidence, Mars' closest approach to Earth occurs on the same night as a total lunar eclipse.

Weather permitting, observers could see a blood-red appear to glide just south of ruddy Mars as it passes through Earth's shadow in the late-night sky.

This should make the planet easy to spot in the constellation Virgo while the moon, just a few degrees south, is in total eclipse as seen from North America.

The total lunar eclipse starts at 2 a.m. EDT (0600 GMT) on April 15. The moon will spend 78 minutes in total starting around 3 a.m.

The moon will turn a Martian-looking red during the eclipse due to light from the sun shining through the Earth's atmosphere.

Gemini Observatory: A new object at the edge of our Solar System

These are the discovery images of 2012 VP113, affectionately called 'Biden' because of the VP in the provisional name. 

It has the most distant orbit known in our Solar System. 

Three images of the night sky, each taken about two hours apart, were combined into one.

The first image was artificially colored red, second green and third blue. 

2012 VP113 moved between each image as seen by the red, green and blue dots. 

The background stars and galaxies did not move and thus their red, green and blue images combine to showup as white sources. 

Credit: Scott Sheppard and Chad Trujillo

The Solar System has a new most-distant member, bringing its outer frontier into focus.

New work from Scott Sheppard of Carnegie and Chadwick Trujillo of the Gemini Observatory reports the discovery of a distant dwarf planet, called 2012 VP113, which was found beyond the known edge of the Solar System.

This is likely one of thousands of distant objects that are thought to form the so-called inner Oort cloud.

What's more, their work indicates the potential presence of an enormous planet, perhaps up to 10 times the size of Earth, not yet seen, but possibly influencing the orbit of 2012 VP113, as well as other inner Oort cloud objects.

Their findings are published March 27 in Nature.

The paper is Sheppard and Trujillo, “A Sedna-like body with a perihelion of 80 astronomical units,” Nature 507 (27 March, 2014), 471-474.

The known Solar System can be divided into three parts: the rocky planets like Earth, which are close to the Sun; the gas giant planets, which are further out; and the frozen objects of the Kuiper belt, which lie just beyond Neptune's orbit.

Beyond this, there appears to be an edge to the Solar System where only one object, Sedna, was previously known to exist for its entire orbit.

But the newly found 2012 VP113 has an orbit that stays even beyond Sedna, making it the furthest known in the Solar System.

"This is an extraordinary result that redefines our understanding of our Solar System," says Linda Elkins-Tanton, director of Carnegie's Department of Terrestrial Magnetism.

These images show the discovery of the new inner Oort cloud object 2012 VP113 taken about 2 hours apart on UT November 5, 2012. 

The motion of 2012 VP113 clearly stands out compared to the steady state background stars and galaxies. 

Credit: Scott S. Sheppard: Carnegie Institution for Science

Sedna was discovered beyond the Kuiper Belt edge in 2003, and it was not known if Sedna was unique, as Pluto once was thought to be before the Kuiper Belt was discovered.

With the discovery of 2012 VP113 it is now clear Sedna is not unique and is likely the second known member of the hypothesized inner Oort cloud, the likely origin of some comets.

2012 VP113's closest orbit point to the Sun brings it to about 80 times the distance of the Earth from the Sun, a measurement referred to as an astronomical unit or AU.

For context, the rocky planets and asteroids exist at distances ranging between .39 and 4.2 AU.

Gas giants are found between 5 and 30 AU, and the Kuiper belt (composed of thousands of icy objects, including Pluto) ranges from 30 to 50 AU.

In our solar system there is a distinct edge at 50 AU. Only Sedna was known to stay significantly beyond this outer boundary at 76 AU for its entire orbit.

More information: Paper: dx.doi.org/10.1038/nature13156

ALMA observes icy wreckage in nearby solar system: Hidden planet causing rapid-fire comet collisions

This artist's concept illustrates the preferred model for explaining ALMA observations of Beta Pictoris. 

At the outer fringes of the system, the gravitational influence of a hypothetical giant planet (bottom left) captures comets into a dense, massive swarm (right) where frequent collisions occur. 

Credit: NASA's Goddard Space Flight Center/F. Reddy

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope have discovered the splattered remains of comets colliding together around a nearby star; the researchers believe they are witnessing the total destruction of one of these icy bodies once every five minutes.

The "smoking gun" implicating this frosty demolition is the detection of a surprisingly compact region of carbon monoxide (CO) gas swirling around the young, nearby star Beta Pictoris.

Bill Dent

"Molecules of CO can survive around a star for only a brief time, about 100 years, before being destroyed by UV radiation," said Bill Dent, a researcher at the Joint ALMA Office in Santiago, Chile, and lead author on a paper published in the journal Science online at the Science Express website.

"So unless we are observing Beta Pictoris at a very unusual time, then the carbon monoxide we observed must be continuously replenished."

Comets and other icy bodies trap vast amounts of CO and other gases in their frosty interiors. When these objects collide, as is common in the chaotic environment around a young star, they quickly release their stored gases.

If these collisions were occurring randomly in this system, then the CO would be more or less evenly distributed.

But the new images from ALMA show something else: a single compact clump of CO approximately 13 billion kilometers (8 billion miles) from the star—or about three times the distance of Neptune to the Sun.

"This clump is an important clue to what's going on in the outer reaches of this young planetary system," says Mark Wyatt, an astronomer at the University of Cambridge and coauthor on the paper.

The ALMA image of carbon monoxide around Beta Pictoris (above) can be deprojected (below) to simulate a view looking down on the system, revealing the large concentration of gas in its outer reaches. 

For comparison, orbits within the solar system are shown for scale. 

Credit: ALMA (ESO/NAOJ/NRAO) and NASA's Goddard Space Flight Center/F. Reddy

Earlier observations of Beta_Pictoris with other telescopes revealed that it is surrounded by a large disk of dusty debris and harbours at least one planet orbiting approximately 1.2 billion kilometers (750 million miles) from the star.

The new ALMA data suggest, however, that there may be a second, as-yet-undetected planet orbiting much farther out.

The gravity from such a planet would shepherd millions of cometary bodies into a relatively confined area.

A similar phenomenon is seen in our own solar system where the planet Jupiter keeps a group of so-called Trojan asteroids in a confined orbit around the Sun.

Aki Roberge

"To get the amount of CO we observed—which is equal to about one-sixth the mass of Earth's oceans—the rate of collisions would be truly startling, with the complete destruction of a large comet once every five minutes," noted Aki Roberge, an astronomer at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and coauthor on the paper.

"To get this number of collisions, this would have to be a very tight, massive swarm."

More information: "Molecular Gas Clumps from the Destruction of Icy Bodies in the β Pictoris Debris Disk," by W.R.F. Dent, Science, 2014.

Is Alpha Centauri B 'superhabitable' world?

The search for extraterrestrial life extends far beyond Earth's solar system, looking for planets or moons outside the "stellar habitable zone" that may have environments even more favorable to supporting life than here on Earth.

These superhabitable worlds have unique characteristics and are ideal targets for extrasolar exploration, as described in a provocative Hypothesis Article in Astrobiology.

René Heller

In "Superhabitable Worlds" René Heller, McMaster University (Hamilton, Ontario, Canada) and John Armstrong, Weber State University (Ogden, UT), propose how tidal heating can create conditions in which life could emerge on an icy or terrestrial planet or moon once thought to be uninhabitable.

"A great place for hydrothermal microorganisms and a volcanic eruption in the weather forecast every morning and evening," says Norman Sleep, Senior Editor for Astrobiology and Professor in the School of Earth Sciences at Stanford University, "a tidally heated planet would be unpleasant though spectacular to visit."

Astronomers discover planet that shouldn't be there

This is an artist's conception of a young planet in a distant orbit around its host star. 

The star still harbours a debris disk, remnant material from star and planet formation, interior to the planet's orbit (similar to the HD106906 system). 

Credit: NASA/JPL-Caltech

An international team of astronomers, led by a University of Arizona graduate student, has discovered the most distantly orbiting planet found to date around a single, sun-like star.

It is the first exoplanet – a planet outside of our solar system – discovered at the UA.

Weighing in at 11 times Jupiter's mass and orbiting its star at 650 times the average Earth-Sun distance, planet HD 106906b is unlike anything in our own Solar System and throws a wrench in planet formation theories.

"This system is especially fascinating because no model of either planet or star formation fully explains what we see," said Vanessa Bailey, who led the research.

Bailey is a fifth-year graduate student in the UA's Department of Astronomy.

It is thought that planets close to their stars, like Earth, coalesce from small asteroid-like bodies born in the primordial disk of dust and gas that surrounds a forming star.

However, this process acts too slowly to grow giant planets far from their star. Another proposed mechanism is that giant planets can form from a fast, direct collapse of disk material.

However, primordial disks rarely contain enough mass in their outer reaches to allow a planet like HD 106906b to form.

Several alternative hypotheses have been put forward, including formation like a mini binary star system.

"A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit," Bailey explained.

"It is possible that in the case of the HD 106906 system the star and planet collapsed independently from clumps of gas, but for some reason the planet's progenitor clump was starved for material and never grew large enough to ignite and become a star."

According to Bailey, one problem with this scenario is that the mass ratio of the two stars in a binary system is typically no more than 10-to-1.

"Every new directly detected planet pushes our understanding of how and where planets can form," said co-investigator Tiffany Meshkat, a graduate student at Leiden Observatory in the Netherlands.

"This planet discovery is particularly exciting because it is in orbit so far from its parent star. This leads to many intriguing questions about its formation history and composition."

"Discoveries like HD 106906 b provide us with a deeper understanding of the diversity of other planetary systems."

More information: The research paper, "HD 106906 b: A Planetary-mass Companion Outside a Massive Debris Disk," has been accepted for publication in The Astrophysical Journal Letters and will appear in a future issue. An online version is available for download at arxiv.org/abs/1312.1265

Mozart, Bach and Beethoven leave solar system in Voyager-1 spacecraft

A selection of classical music travelling on the Voyager 1 spacecraft at 100,000mph has made it outside our solar system, and is now 11.6 billion miles away from Earth.

Launched in 1977, Voyager 1 is a remarkable piece of 70's technology but is an intergalactic relic by today's aerospace and communications standards.

Voyager 1 and 2 were originally launched to study the outer planets, and having successfully completed their missions, have now travelled further than anyone or anything in human history. 

Voyager 1 is so far away and has such poor broadcasting capability that it takes 17 hours for the weak radio signal sent from the craft to be picked up on Earth.

Along with greetings in 55 languages, music submitted by countries across the world was transferred onto a gold vinyl record to serve as a message to any life form that might someday stumble across the spacecraft. 

The out-of-this-world playlist includes jazz by Louis Armstrong, traditional tunes from different continents, and classical music by great composers including Bach, Stravinsky, Beethoven and Mozart.

The spacecraft will not approach another star for nearly 40,000 years. By this time, the plutonium power sources will have run out of power and the 20W transmitters will have stopped broadcasting a signal, so there's no way of knowing whether alien life forms will have discovered the music - or worked out how to play it.

Picture: NASA

See a Full list of music on the Voyager spacecraft here

NASA Voyager-1 has left the Solar System

An artist's concept shows the Voyager spacecraft traveling through space against a field of stars. 

Credit: NASA/JPL-Caltech.

University of Iowa space physicist Don Gurnett says there is solid evidence that NASA's Voyager 1 spacecraft has become the first man-made object to reach interstellar space, more than 11 billion miles distant and 36 years after it was launched.

The finding is reported in a paper published in the Sept. 12 online issue of the journal Science.

Don Gurnett

"On April 9, the Voyager 1 Plasma Wave instrument, built at the UI in the mid-1970s, began detecting locally generated waves, called electron plasma oscillations, at a frequency that corresponds to an electron density about 40 times greater than the density inside the heliosphere—the region of the sun's influence," says Gurnett.

"The increased electron density is very close to the value scientists expected to find in the interstellar medium.

"This is the first solid evidence that Voyager 1 has crossed the heliopause, the boundary between the heliosphere, and interstellar space," says Gurnett, principal investigator for the plasma wave instrument.

Bill Kurth

For several months, the relative position of Voyager 1 has stirred something of a scientific debate because there remains some lingering evidence of the nearby heliosphere beyond the heliopause.

Even though Voyager 1 has passed into interstellar space, it does not mean that its journey is over, says Bill Kurth, UI research scientist and co-author of the Science paper.

This is an artist's impression of Voyager 1's position on the sky when observed by the Very Long Baseline Array (VLBA) on Feb. 21, 2013, at which point -- according to NASA's Jet Propulsion Laboratory -- Voyager was already outside of our solar system. 

The actual image from the data (enlarged section) is 0.5 arcseconds across. 

The radio signal as shown is a mere 1 milliarcsecond across. 

Credit: Alexandra Angelich, NRAO/AUI/NSF.

"Now that we're on the outside, we are learning that interstellar space isn't a bland region," Kurth says.

"Rather, there are variations in some of Voyager's measurements that may be due to the nearby presence of the heliosphere. So, our attention is turning from crossing the boundary to understanding what is going on outside," he says.

At age 36, Voyager 1 is the most distant human-made object at more than 11.6 billion miles from the sun, or about 125 astronomical units.

"At that distance it takes more than 17 hours for a radio signal to travel from the spacecraft to one of NASA's Deep Space Network antennas. The signal strength is so incredibly weak that it takes both a 230-foot and a 110-foot-diameter antenna to receive our highest resolution data," Gurnett says.

Launched Sept. 5, 1977, Voyager 1 completed flybys of both Jupiter and Saturn and is currently moving outward from the sun at about 3.5 AU per year.

It's sister spacecraft, Voyager 2 was launched Aug. 20, 1977, on a flight path that took it to encounters with Jupiter, Saturn, Uranus, and Neptune.

At present, Voyager 2 is still inside the heliosphere about 103 AU from the sun and traveling outward at about 3.3 AU per year.

More information: The sounds of the electron plasma oscillations heralding Voyager's entry into interstellar space and other sounds of space can be heard by visiting Gurnett's website at: www-pw.physics.uiowa.edu/space-audio/

Tamu Massif: Monster volcano is one of the biggest in Solar System

MCS reflection Line A–B, across the axis of Tamu Massif. 

Credit: Nature

Geologists on Thursday announced they had uncovered a stupendous volcano that is the biggest in the world and rivals the greatest in the Solar System.

Dubbed Tamu Massif, the volcano is part of the Shatsky Rise, a deep plateau on the floor of the Pacific located around 1,600 kilometres (1,000 miles) east of Japan, they said.

It comprises a single, immense, rounded dome in the shape of a shield, formed of hardened lava from an eruption around 144 million years ago.

It covers around 310,000 square kilometres (119,000 square miles)—the equivalent area of Britain and Ireland combined—and slopes upwards to a height of around 3.5 kms (2.2 miles) above the sea floor.

"Tamu Massif is the largest known single, central volcano in the world," the team reported in the journal Nature Geoscience.

The slope of lava layers within Tamu Massif indicate that it formed from a central volcanic vent.

William Sager, University of Houston

In area, "it is... approximately the same as the British Isles or Olympus Mons on Mars, which is considered the largest volcano in the Solar System."

It adds: "Although Olympus Mons seems to be a giant because it is more than 20 kms (12 miles) in height, its volume is only around 25 percent larger."

Olympus Mons, in addition, has relatively shallow roots, whereas Tamu Massif delves some 30 kilometres (18 miles) into Earth's crust.

Ocean surveyors had until now surmised Tamu Massif to be a vast system of multiple volcanoes, a kind that exists in about a dozen locations around the planet.

The realisation that it was a single volcano of truly massive size only came to light when the team, led by William Sager at Texas A&M University, sought an overview.

They assembled data from rock samples, taken from an ocean-floor drilling project, and a chart of the seabed, provided by deep-penetration seismic scanners aboard a survey ship.

Put together, the findings suggest mega-volcanoes found in other parts of the Solar System have cousins on Earth, says the paper.

"The Earth variety is poorly understood because these monsters found a better place to hide—beneath the sea," it argues.

In an email exchange with AFP, Sager said it seemed unlikely that Tamu Massif was still active.

"The bottom line is that we think that Tamu Massif was built in a short (geologically speaking) time of one to several million years and it has been extinct since," he said.

"One interesting angle is that there were lots of oceanic plateaus (that) erupted during the Cretaceous Period (145-65 million years ago) but we don't see them since. Scientists would like to know why."

Other volcanic leviathans could be lurking among the dozen or so large oceanic plateaux around the world, he thought.

More information: dx.doi.org/10.1038/ngeo1934

NASA IBEX: Interstellar winds buffeting our solar system have shifted direction

This image shows the nearest interstellar gas clouds around the solar system, including the Local Interstellar Cloud (LIC) and G Cloud, along with positions of neighboring stars in the plane of our Milky Way galaxy. 

The arrow shows the sun's motion relative to neighboring stars. 

Image courtesy of P.C. Frisch, University of Chicago

Scientists, including University of New Hampshire astrophysicists involved in NASA's Interstellar Boundary Explorer (IBEX) mission, have discovered that the particles streaming into the solar system from interstellar space have likely changed direction over the last 40 years.

The finding helps scientists map our location within the Milky Way galaxy and is crucial for understanding our place in the cosmos through the vast sweep of time—where we've come from, where we're currently located, and where we're going in our journey through the galaxy.

Additionally, scientists now gain deeper insight into the dynamic nature of the interstellar winds, which has major implications on the size, structure, and nature of our sun's heliosphere—the gigantic bubble that surrounds our solar system and helps shield us from dangerous incoming galactic radiation.

The results, based on data spanning four decades from 11 different spacecraft, including IBEX, were published in the journal Science September 5, 2013.

Eberhard Möbius

"It was very surprising to find that changes in the interstellar flow show up on such short time scales because interstellar clouds are astronomically large," says Eberhard Möbius, UNH principal scientist for the IBEX mission and co-author on the Science paper.

Adds Möbius, "However, this finding may teach us about the dynamics at the edges of these clouds—while clouds in the sky may drift along slowly, the edges often are quite fuzzy and dynamic. What we see could be the expression of such behaviour."

The data from the IBEX spacecraft show that neutral interstellar atoms are flowing into the solar system from a different direction than previously observed.

Interstellar atoms flow past the Earth as the interstellar cloud surrounding the solar system passes the sun at 23 kilometers per second (50,000 miles per hour).

The various sets of observations relied on three different methods to measure the incoming interstellar wind. IBEX and Ulysses directly measured neutral helium atoms as they coursed through the inner solar system.

IBEX's measurements are close to Earth, while Ulysses' measurements were taken between 1.3 and 2 times further from the sun.

Nathan Schwadron

In the final analysis, the direction of the wind obtained most recently by IBEX data differs from the direction obtained from the earlier measurements, which strongly suggests the wind itself has changed over time.

"Prior to this study, we were struggling to understand why our current measurements from IBEX differed from those of the past," says co-author Nathan Schwadron, lead scientist for the IBEX Science Operations Center at UNH.

"We are finally able to resolve why these fundamental measurements have been changing with time: we are moving through a changing interstellar medium."

More information: "Decades-Long Changes of the Interstellar Wind Through Our Solar System," by P.C. Frisch et al Science, 2013.

Solar System: Life began on Mars - Boron and Molybdenum

New evidence has emerged which supports the long-debated theory that life on Earth may have started on Mars.

Professor Steven Benner will tell geochemists gathering today (Thursday 29 Aug) at the annual Goldschmidt conference that an oxidized mineral form of the element molybdenum, which may have been crucial to the origin of life, could only have been available on the surface of Mars and not on Earth.

"In addition", said Professor Benner "recent studies show that these conditions, suitable for the origin of life, may still exist on Mars."

"It's only when molybdenum becomes highly oxidized that it is able to influence how early life formed," explains Professor Benner, from The Westheimer Institute for Science and Technology in the USA.

"This form of molybdenum couldn't have been available on Earth at the time life first began, because three billion years ago the surface of the Earth had very little oxygen, but Mars did. It's yet another piece of evidence which makes it more likely life came to Earth on a Martian meteorite, rather than starting on this planet."

The research Professor Benner will present at the Goldschmidt conference tackles two of the paradoxes which make it difficult for scientists to understand how life could have started on Earth.

The first is dubbed by Professor Benner as the 'tar paradox'. All living things are made of organic matter, but if you add energy such as heat or light to organic molecules and leave them to themselves, they don't create life. Instead, they turn into something more like tar, oil or asphalt.

"Certain elements seem able to control the propensity of organic materials to turn into tar, particularly boron and molybdenum, so we believe that minerals containing both were fundamental to life first starting," says Professor Benner.

"Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidized form of molybdenum was there too."

The second paradox is that life would have struggled to start on the early Earth because it was likely to have been totally covered by water.

Not only would this have prevented sufficient concentrations of boron forming – it's currently only found in very dry places like Death Valley – but water is corrosive to RNA, which scientists believe was the first genetic molecule to appear.

Although there was water on Mars, it covered much smaller areas than on early Earth.

"The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock," says Professor Benner.

"It's lucky that we ended up here nevertheless, as certainly Earth has been the better of the two planets for sustaining life. If our hypothetical Martian ancestors had remained on Mars, there might not have been a story to tell."

More information: goldschmidt.info/2013/