NASA Probe: Our Solar System Is Smooshed

When viewed from the rest of the galaxy, the edge of our solar system appears slightly dented as if a giant hand is pushing one edge of it inward, far-traveling NASA probes reveal.

Information from Earth's first space probes to hit the thick edge of the solar system -- called the "heliosheath" where the solar wind slows abruptly -- paint a picture that is not the simple circle that astronomers long thought, according to several studies published Thursday in the journal Nature.

Surprised astronomers said they will have to change their models for what the solar system looks like.

Different Distances From the Sun

In 1977, NASA launched two space probes on missions beyond the solar system. Voyager 1 went north and Voyager 2 went south. What startled astronomers is that when the two of them hit the heliosheath they did so at different distances from the sun.

Voyager 2 hit the southern edge of the solar system nearly 1 billion miles closer to the sun than Voyager 1 did to the north. Voyager 2 hit the edge at 7.8 billion miles from the sun.

"We used to assume that it's all symmetric and simple,"

said Leonard Burlaga, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Md.

"It's literally like a hand pushing."

Interstellar Turbulence

That push is from the magnetic field that lies between star systems in the Milky Way. The magnetic field hits the solar system at a different angle on the south than on the north, probably because of interstellar turbulence from star explosions, said Voyager project scientist Ed Stone.

Both spacecraft still have several more years before they completely exit the solar system and continue deeper into the space between stars, said Stone, former director of NASA's Jet Propulsion Lab.

Quantum Computing In Semiconductors

The odd behavior of a molecule in an experimental silicon computer chip has led to a discovery that opens the door to quantum computing in semiconductors.

In a Nature Physics journal paper currently online, the researchers describe how they have created a new, hybrid molecule in which its quantum state can be intentionally manipulated - a required step in the building of quantum computers.

"Up to now large-scale quantum computing has been a dream,"

says Gerhard Klimeck, professor of electrical and computer engineering at Purdue University and associate director for technology for the national Network for Computational Nanotechnology.

"This development may not bring us a quantum computer 10 years faster, but our dreams about these machines are now more realistic."

The workings of traditional computers haven't changed since they were room-sized behemoths 50 years ago; they still use bits of information, 1s and 0s, to store and process information. Quantum computers would harness the strange behaviors found in quantum physics to create computers that would carry information using quantum bits, or qubits. Computers would be able to process exponentially more information.

If a traditional computer were given the task of looking up a person's phone number in a telephone book, it would look at each name in order until it found the right number. Computers can do this much faster than people, but it is still a sequential task. A quantum computer, however, could look at all of the names in the telephone book simultaneously.

Quantum computers also could take advantage of the bizarre behaviors of quantum mechanics - some of which are counterintuitive even to physicists - in ways that are hard to fathom. For example, two quantum computers could, in concept, communicate instantaneously across any distance imaginable, even across solar systems.

Albert Einstein, in a letter to Erwin Schrödinger in the 1930s, wrote that in a quantum state a keg of gunpowder would have both exploded and unexploded molecules within it (a notion that led Schrödinger to create his famous cat-in-a-box thought experiment).

This "neither here nor there" quantum state is what can be controlled in this new molecule simply by altering the voltage of the transistor.

Until now, the challenge had been to create a computer semiconductor in which the quantum state could be controlled, creating a qubit.

"If you want to build a quantum computer you have to be able to control the occupancy of the quantum states,"

Klimeck says.

"We can control the location of the electron in this artificial atom and, therefore, control the quantum state with an externally applied electrical field."

The discovery began when Sven Rogge and his colleagues at Delft University of Technology in the Netherlands were experimenting with nano-scale transistors that show the effects of unintentional impurities, or dopants. The researchers found properties in the current-voltage characteristics of the transistor that indicated electrons were being transported by a single atom, but it was unclear what impurity was causing this effect.

Physicist Lloyd Hollenberg and colleagues at the University of Melbourne in Australia were able to construct a theoretical silicon-based quantum computer chip based on the concept of using an individual impurity.

"The team found that the measurements only made sense if the molecule was considered to be made of two parts,"

Hollenberg says. "One end comprised the arsenic atom embedded in the silicon, while the 'artificial' end of the molecule forms near the silicon surface of the transistor. A single electron was spread across both ends.

"What is strange about the 'surface' end of the molecule is that it occurs as an artifact when we apply electrical current across the transistor and hence can be considered 'manmade.' We have no equivalent form existing naturally in the world around us."

Klimeck, along with graduate student Rajib Rahman, developed an updated version of the nano-electronics modeling program NEMO 3-D to simulate the material at the size of 3 million atoms.

"We needed to model such a large number of atoms to see the new, extended quantum characteristics,"

Klimeck says.

The simulation showed that the new molecule is a hybrid, with the naturally occurring arsenic at one end in a normal spherical shape and a new, artificial atom at the other end in a flattened, 2-D shape. By controlling the voltage, the researchers found that they could make an electron go to either end of the molecule or exist in an intermediate, quantum, state.

This model was then made into an image by David Ebert, a professor of electrical and computer engineering at Purdue, and graduate student Insoo Woo.

Delft's Rogge says the discovery also highlights the current capabilities of designing electronic machines.

"Our experiment made us realize that industrial electronic devices have now reached the level where we can study and manipulate the state of a single atom,"

Rogge says.

"This is the ultimate limit, you can not get smaller than that."

Source: Purdue University

Galileo demo sat to be despatched

Giove-B, the second demonstrator spacecraft for Europe's proposed satellite navigation system, is finally to be sent for launch.

The craft, currently held at a test centre in Holland, will be despatched to the Baikonur spaceport next week for a Soyuz flight in late April.

Giove-B will trial key technologies for the Galileo project, including the most advanced atomic clock to go into orbit.

Precise timing is one of the principal elements of any sat-nav system.

The passive hydrogen maser device on the new spacecraft will keep time with an accuracy of better than one nanosecond (billionth of a second) in 24 hours.

The European Commission and the European Space Agency, which together are driving the Galileo venture, hope such technologies can bring a leap forward in performance over the existing American GPS (Global Positioning System).

They believe improvements in accuracy and reliability can spark a multi-billion-euro industry in which receivers find their way into many more markets - from mobile phones to safety-critical applications such as guided trains and buses.

Component failure

At one stage, Giove-B was being built in parallel with Giove-A, the first test platform launched in December 2005.

But the former's preparation was then hit by lengthy delays, including a major setback when a component blew on the spacecraft whilst it was sitting in a thermal vacuum chamber designed to assess the satellite's ability to withstand the extreme conditions of space.

"It was a capacitor that failed; and you can imagine, you then have to stop the test sequence and have an analysis,"

explained Reinhold Lutz from manufacturer EADS Astrium.

"It took two or three months to determine what really was the problem, and then we had to dismantle the satellite to replace each capacitor. And we had to do it not just on Giove-B but on all our satellites.

"This exercise alone took almost one year."

After the repairs and modifications, Giove-B would have been ready for flight in December 2007, but has since had to wait for a rocket to become available to take it into space.

Money package

Giove-B's woes have to some degree mirrored those of the Galileo project as a whole.

The sat-nav venture came close to being cancelled last year when the private consortium selected to build and operate the system collapsed.

European Union finance ministers had to step in with a 3.4bn-euro public funding package to keep Galileo alive.

Galileo cannot truly proceed until the money is released, and that requires the formal agreement of the EU's legislative arms.

BUILDING THE SPACE SEGMENT OF GALILEO 2 demonstrators will test key technologies; Giove-A is in orbit now In addition, 30 satellites are needed for the full Galileo system First 4 spacecraft in the constellation have already been ordered Remaining 26 yet to be ordered; they will be launched in batches A mix of medium- and heavy-lift rockets could do the job The timeline is challenging whichever rocket system is used

"What is needed now is a regulation, a legal instrument, which is necessary to allow us to spend the money,"

said Paul Verhoef, who heads up the Galileo Unit at the European Commission.

"The target is to come to an agreement even before Easter. It then needs some formal adoptions in plenaries and eventually it will enter into force. The date is not precisely known but it is expected to be May or early June."

He added:

"It would come to delays only if in the next two weeks the [Council of Ministers and the European Parliament] don't come to agreement. But this is not expected."

A raft of technical issues have to be addressed if Galileo is to become a fully functioning civil sat-nav service that, unlike military systems, gives guarantees to users over performance.

Issues such as liability have to be sorted out; who would pay out, and how much, for example, if a Galileo failure was found to be the cause of an aeroplane crashing?

Contracts will be issued later this year to build all aspects of Galileo's vast infrastructure - from the satellites in orbit right through to the ground monitoring and control centres.

Kazakh date

The timeline will be challenging. European ministers have insisted that Galileo should be up and running by the end of 2013. This will require launching a constellation of 30 satellites, the first four going up in 2010.

Giove-B will show whether the technology in these operational spacecraft is robust. As well as its atomic clocks, the latest demonstrator carries a signal generation unit, a complex processing centre that produces the all-important navigation signal.

This signal goes through an amplification system and is then converted to the three frequency bands over which Galileo will work. This will enable engineers to test the Galileo system across the full spectrum it intends to use to transmit its five sat-nav services.

"Giove-B is 95% identical to the final constellation satellites,"

said Reinhold Lutz.

"It is much more complex than Giove-A and can transmit the right waveforms simultaneously in all three bands."

Giove-B will leave the European Space Agency's research and technology centre (ESTEC) in Noordwijk, the Netherlands, on Tuesday, and fly to Moscow. It will then travel on to Baikonur, Kazakhstan, on the following Thursday.

The launch on a Soyuz-Fregat vehicle is timed for 0416 local time on Sunday 27 April (2216 GMT on Saturday 26 April).

Giove-B will be placed in a medium-Earth orbit 23,222km above the planet's surface.

It should begin its first transmissions in May.

Giove-A, produced by the UK firm Surrey Satellite Technology Limited, has worked flawlessly in orbit for two years.

THE FIVE GALILEO SERVICES
NAVIGATION	Open Access	This will be 'free to air' and for use by the mass market; simple timing and positioning down to 1m
	Commercial	Encrypted; high accuracy at the cm scale; guaranteed service for which service providers will charge fees
	Safety of life	Open service; for applications where guaranteed accuracy is essential; integrity messages warn of errors
	Public regulated	Encrypted; continuous availability even in time of crisis; government agencies will be main users
SAR	Search and Rescue	System will pick up distress beacon locations; feasible to send feedback, confirming help is on its way

Giant telescope opens both eyes

The world's most powerful optical telescope has opened both of its eyes.

Astronomers at the Large Binocular Telescope (LBT) in Arizona have released the first images taken using its two giant 8m diameter mirrors.

The detailed pictures show a spiral galaxy located 102 million light-years away from the Milky Way.

LBT has been 20 years in the making but promises to allow astronomers to probe the Universe further back in time and in more detail than ever before.

"The amount of time and work that was put into this project to reach the point where we are today is immense,"

said LBT Director Richard Green.

"To see the telescope operational with both mirrors is a great feeling."

The $120m (£60m) telescope uses two mirrors in tandem to maximise the amount of light it gathers, which allows astronomers to look deep into the Universe.

Using two 8.4 m (27ft) mirrors will give LBT the equivalent light-gathering capacity of a single 11.8m (39ft) instrument and the resolution of a 22.8m (75ft) telescope.

Impressive detail

The resolution is 10 times greater than the space-based Hubble telescope, which has a 2.4m (8ft) mirror.

"The images that this telescope will produce will be like none seen before,"

said Professor Peter Strittmatter of the University of Arizona.

The first pictures are false-colour images of the spiral galaxy NGC 2770. The pictures show what is a flat disc of stars and glowing gas.

The images - which take advantage of the telescope's ability to view the same point in space with multiple wavelengths of light - emphasise different features of the galaxy.

Combining ultraviolet and green light shows up clumpy regions of newly formed hot stars in the spiral arms, whilst a combination of red wavelengths highlights older, cooler stars.

The images were taken on 11 and 12 January but have only just now been released.

The LBT is located on Mount Graham in southeastern Arizona. It achieved "first light" with one mirror on 12 October 2005 when it imaged a spiral galaxy in the constellation of Andromeda.