A Practice Science News Article

This was my first introduction to writing a quick science news article that would go into something like the New York Times.  We were supposed to create the article based off a press release and the original paper.  My article was about a small advance toward making quantum computers.  I've already gotten comments from my professor, but more feedback is welcome, from people with and without a science or journalism background .

That’s one small twist for electrons, one ten-second leap for computer technology


Quantum computers would be able to perform 100 billion calculations nearly instantaneously and solve problems in a few months that would take even our fastest computers millions of years.  While scientists have made plenty of theoretical developments regarding quantum advances in engineering such devices have been slow in coming.  But an international team of researchers is now one step closer to a physical quantum computer after developing a new method to control certain properties of electrons.

Scientists Stephen Lyon and Alexei Tyryshkin controlled the electrons in a bar of silicon, cooled to just above absolute zero, by sending pulses of microwaves across the bar, thereby arranging the electrons in an ordered manner.  The orderliness of the electrons is what allows quantum computers to work.  As long as the electrons remain ordered, the computer has access to the information stored in the particles.

Previously, Lyon’s group was able to keep the electrons ordered for about 60 milliseconds.  Using their new method, they were able to maintain order for 10 seconds.  Other researchers have kept electrons ordered for at least hundreds of seconds, but their techniques do not use silicon, which will put them at a disadvantage when it comes time to manufacture the computer parts.

The property that allows information to be stored in electrons is the same property that Lyon and Tyryshkin must control.  This property is known as “spin” and it is a fundamental characteristic of electrons.  Spin can be thought of as the property of electrons that allows each electron to create a small magnetic field.  An electron’s spin can either be “up” or “down”, similar to how standard binary computers use either a 0 or a 1 to encode information.  An electron’s spin can also be in a “superposition”, in which its spin is both up and down.  This superposition has no analog on a macroscopic scale and is what gives quantum computers their incredible computing ability.

The microwaves that the group pulsed across the silicon allowed the researchers to control the electrons’ spin.  “The first pulse twists them, the second reverses them, and at some point the sample itself produces a microwave pulse, and we call that the echo,” Lyon stated in a press release in January.  “By doing the second pulse, getting everything to reverse, we get the electrons into phase.”  While the electrons are “in phase,” the spins of the electrons are coordinated, and the information encoded in the spin of the electrons is accessible for calculations.

Once the spin of the electrons becomes uncoordinated, the information is no longer accessible.  Therefore, developments that allow scientists control over the electrons’ spin for increasingly longer periods of time are absolutely necessary before a quantum computer can be built.  As Tyryshkin puts it, “The bottom line is, you want [coherence] as long as possible.”

Magnetism is one of the ways the electrons can become uncoordinated.  One of the reasons Lyon and Tyryshkin were successful in increasing the time the electrons’ spin remained coherent was because they were able to reduce the magnetism interfering with the electrons in the silicon bar.  Some versions of silicon will produce their own magnetic fields, depending on how the atoms are structured, while some are magnetically silent.  The team had to find the version of silicon that would produce the least magnetism.  This happened to be silicon-28.

Lyon and Tyryshkin purified the silicon so it contained very few contaminants, such as silicon-29, which produces plenty of magnetism.  In fact, they purified their sample so well, that they were worried the sample would not respond to the microwave pulses.  The response the silicon puts out due to the microwaves is how the researchers know the electrons’ spins have become aligned.  To make the sure that the silicon would produce a response to the microwaves, they had to introduce some phosphorus to the sample, a process that took extreme precision.

“A lot of the work boils down to getting the phosphorous far enough apart,” Lyon said.  Too much and the magnetism that will disorder the electrons returns; too little and the sample remains unresponsive to the microwaves and the scientists have no way of knowing how the electrons are reacting.  “It has taken quite a bit of work to get to this point,” Lyon said.  “Nine years of refining measurements and materials.”  Michael Thewalt, a physics professor at Simon Fraser University and Kohei Itoh, a professor at Keio University, helped obtain the necessary amounts of silicon.

The temperature of the silicon also plays a part in reducing magnetic noise.  The silicon was cooled to 2 kelvin (A kelvin is a unit of temperature, like degrees Fahrenheit or degrees Celsius).  For comparison, the vacuum of space is about 3 kelvin, and at 0 kelvin, or absolute zero, all thermal heat vanishes.  The low temperature reduces magnetic activity, which helps keep the electrons ordered, and their information available, longer.

While Lyon and his team have made substantial progress toward making quantum computing a reality (their work was published in Nature Materials in December 2011) by twisting and turning their electrons at their will, extending electron coherence time is only one obstacle delaying the creation of a quantum computer.  Researchers still need to find a way to increase the amount of information that the computer can handle at one time.

Currently, Lyon and Tyryshkin have the equivalent of one “qubit” of information.  A qubit is the smallest unit of information a quantum computer could deal with, similar to a 0 or a 1 for a regular computer.  Tyryshkin explained that future computers will need to control and access many more qubits.  “Right now, we are using one,” he said.  “If we could come up with a thousand, that would be a very interesting machine.”

Scientists have yet to determine how many qubits are necessary and how long the electrons would have to remain coordinated in order to create a functional quantum computer.  But when all the pieces of research and engineering finally come together, it will signal a computing revolution.

Detecting Planets

I wrote this as an extended definition or explanation of some scientific concept.  Specifically, I explain some of the methods we use to detect extra-solar planets.

Searching for a Needle in the Cosmos

We have long searched for a planet that is as hospitable to life as the Earth.  Such a planet would have to have a solid surface and be large enough to maintain its orbit, but not too large as to crush any life from gravitational influence. The planet would also have to be at the correct distance from its host star as to stay at a reasonable temperature and it would have to have a sufficient amount of atmosphere made out of non-toxic gases.  We have evaluated the ability of the planets within our solar system to be hospitable to life.  Some have potential, but most fall short of our requirements.  This is not a problem for astronomers, though, because there are billions and billions of planets hundreds of light years away, happily orbiting a star that is not our sun.  Any one of them could have the traits needed to host life.  Not wanting to leave these extra-solar planets uninvestigated, astronomers have developed techniques to detect planets outside our solar system.  The new techniques not only detect planets, but also inform us about the presence of characteristics necessary for supporting life on said planets.  How can this be?  How are astronomers able to detect these pinpoints of rock and gas in our ever-expanding universe, these needles in a cosmological haystack?  And how can they determine if these planets can host life?

            One of the most common methods astronomers use to detect and measure the mass of extra-solar planets is the transit method, in which the brightness of the planet’s host star is consistently measured.  The transit method only works for star-planet pairs that are oriented in such a way that the planet will pass in front of and obscure part of the star as seen from Earth.  This “edge-on” view is in contrast with an orientation where the planet looks like it is tracing out a circle around the star.  Astronomers will record and graph the brightness of the star over some amount of time.  Typically, the graph will show some variation in brightness.

            Many factors may account for the variability of a star’s brightness.  The star may be producing stellar spots, which are equivalent to sun spots, dark patches of low temperatures in comparison to the rest of the star.  The star may be rotating or it may occasionally be obscured with dust.  The way astronomers deduce what is responsible for the variability in the brightness is by looking for a particular pattern in the changes. 

What sort of pattern should we expect to see if a planet is causing the changes in brightness?  Try imagining a planet off to the side of a star.  We would measure the full, regular brightness of the star.  This level of brightness would continue until the planet started to transit, or pass, in front of the star.  Then the detected brightness of the star would continually decrease until the entire planet overlapped the star.  The measured brightness would stay at a minimum value until the leading edge of the planet reached the edge of the star.  At that point, the brightness level would gradually increase back to its original, maximum value, as more of the star was revealed as the planet moved past it.  As the planet continued its orbit, it would eventually pass behind the star.  We would then measure a small decrease in brightness since the light reflected by the planet from the star would no longer reach Earth.  Then, as the planet came around the star again, the whole process would repeat itself.  So a plot tracking the brightness of a star would indicate the presence of a planet if it showed a large dip, then an increase back to a maximum value, then a small dip, then an increase back to the maximum value again, and the pattern repeated.

            The transit method for detecting extra-solar planets is useful for helping astronomers figure out how large a planet is, which, when combined with information gathered from other sources, can help them infer what the planet is made of and how strong gravity is there.  From there, the astronomers can hypothesize about whether such a planet would be hospitable to life.  The ratio of the height of the large drop to the small drop gives astronomers the ratio of the surface areas of the star and the planet.  If the radius of the star is already known, then astronomers can calculate the radius of the planet.  By considering the densities of planets with similar radii, astronomers can then estimate the density, and therefore the mass, of the planet in question.  Knowing how large a planet is can then tell them if it is more likely to be gaseous or solid.  Currently, astrobiologists are more interested in solid planets, because they are more likely to be similar to Earth, and so more likely to be hospitable to life.

            We need to know more than how large a planet is before we can conclude if it would be hospitable to life.  Life, at least as we know it, can only survive within a certain range of temperatures.  To estimate the temperature range of a planet, astronomers must know how large the host star is and how far away from the star the planet is. The “radial velocities” method of detecting extra-solar planets, in which the gravitational effect of the planet on the star is measured, helps inform astronomers about the distance between a detected planet and the star it orbits.  Methods used to calculate the mass of a star are a subject for a different time.

            We often think of a planet orbiting the center of a star, but, in reality, the star and the planet are orbiting a common point in space.  Consider a see-saw.  If there are two five-year olds of equal mass playing on the see-saw, then they can sit equally far away from the center to remain balanced.  If we replace one of the five-year olds with a football player, who is presumably heavier than the five-year old, then the football player must sit closer to the center of the see-saw to maintain balance.  The center of the see-saw happens to be the where the “center of mass” of the five-year old and the football player is located.  Now imagine the see-saw was taken away, but the five-year old and the football player remained suspended in the air.  The center of mass of the two is still where it was when the see-saw was there.  If we moved the football player or the boy, the center of mass would also move.  The center of mass of an object, or a group of objects, is a point in space at which all the mass in the system is balanced. The center of mass may not necessarily be made up of physical matter.

Star and planet systems work pretty much the same way balancing a see-saw does, only instead of moving up and down while the center of mass stays in place, the star and planet orbit the center of mass while it stays in place.  A large difference between the mass of the planet and the mass of the star means that the center of mass will be closer to the star.  As the planet gets more massive, the center of mass moves away from the star.  This does not mean that the more massive planets are closer to the star; just that they have a greater effect on the location of the point that the star and the planet orbit around than smaller planets.  For example, Mercury is closer to the sun than Jupiter, but Jupiter is far more massive.  Because the difference in mass between the sun and Jupiter is smaller than the difference between the sun and Mercury, Jupiter affects the sun’s motion more than Mercury does.  A larger distance between the center of mass and a star makes the difference between the star revolving in place and the star actually moving in a small elliptical orbit.

            How do astronomers take advantage of the fact that a planet can affect a star’s motion by shifting the center of mass away from the star?  If a planet is large enough to cause a star to move in a noticeable orbit around the center of mass, the star is sometimes moving away from Earth and sometimes moving toward Earth (assuming, once again, that we have an edge-on perspective of the system).  As the star moves away from the Earth, the radiation emitted by the star has a longer wavelength, and as the star is moving toward the Earth, the radiation is compressed and has a shorter wavelength.  Astronomers measure the changes in the wavelength of the radiation emitted by the star.  If the changes in wavelength are large, astronomers know that the star must be traveling in a bigger orbit.  After calculating how large the orbit of the star is based on measurements of the changes in the wavelength, astronomers can estimate how large a planet would need to be in order to have an effect of the calculated size on the orbit of the star, assuming they have used other methods to find the mass of the star.

Once the astronomers know how large a planet is, they can then find how far away the planet is from the star through Newton’s law of universal gravitation.  For every planet-star pair there is something called the “Goldilocks zone”, the range of distances from the star in which the planet would be at a temperature hospitable to life.  Astronomers and astrobiologists are hoping that their calculations will lead them to find a small (Earth-sized), rocky planet within its Goldilocks zone, as this planet would have a higher probability of being hospitable to life than other kinds of planets.

            The main constraint on these methods is that it is easier to find large planets, planets a few times the size of Jupiter.  Most of these tend to be gaseous, which isn’t quite what we are looking for.  However, some rocky planets with the mass of several Earths have been discovered.  These discoveries should motivate improvement of the instruments used to uncover extra-solar planets.  Currently, astronomers can detect changes in velocity as small as one meter per second!  That is about as much as Jupiter perturbs the sun’s orbit.  Though it may take years of research, it is within our abilities to create instruments able to detect Earth sized extra-solar planets.  Once we can do that, we may eventually discover a planet as welcoming to life as Earth.  Such a discovery would be as incredible as finding a diamond encrusted needle glinting amidst a pile of dust and hay.

Author’s Note:  In the course of writing this paper, astronomers published results saying they had detected planets Earth-sized and smaller through the Kepler mission.

How I Found Science

My introductory astronomy class has been over for a while now, but I am currently taking “Writing about Science”, a class designed to teach the strategies of writing about science for non-scientists.  I’ve enjoyed the assignments so far, and while I have no idea if I’ll keep this blog going, I thought I’d share some of the stories I’ve written.  This first one is about how I came to be intrigued by science. 

The Penny and the Feather

I was in kindergarten when I met a real psychic for the first time.  I’m not talking about those frauds who tell you to watch out for earthquakes in California, especially in the two weeks preceding and following a full moon.  I mean a person who could actually predict the future accurately.

It was the day of a school assembly and we were all crowded into the gym.  I sat on the hard wood floor, near the front of the room.  Just a few rows away was a table with all sorts of contraptions on it.  I don’t remember most of what was on there, but I do remember a grey cylinder with some black tubes connecting to a clear chamber.  There was a woman standing behind the table.  She eventually got our attention and the assembly began.

There were probably plenty of standard demonstrations of how chemicals can change color when mixed together and how light refracts and splits into a rainbow when it goes through a prism.  Just as I don’t remember most of the equipment that was on the table, I don’t remember most of the experiments that the woman completed.  Except for one.  I was happily – complacently - watching the assembly when the woman said the most ridiculous thing I had ever heard.  She said that she would remove all the air in the clear chamber by using the grey cylinder to pump it out.  This would create a vacuum in the clear chamber.  Next, she would allow a penny and a feather to start falling inside the chamber at the same time.  She then told us, with a completely straight face, that the penny and the feather would hit the bottom of the chamber at the same time.

I was incredulous!  Everybody knew that the feather would slowly float down and land after the penny did.  How could this woman claim such a thing?  “Prove it,” I thought to myself.

The woman behind the table flipped a switch and there was a loud buzzing noise interspersed with glugging sounds as the air was sucked out of the clear chamber.  Once the air was gone, she stopped the pump and set up the feather and the penny at the top of the chamber.  After a count of three, she let go and the most spectacular thing happened.  The penny and the feather hit the bottom of the chamber at the same time!  The woman had been right!  She managed to back up her claim with physical evidence and I had no choice but to change my understanding the world.  This was the power of science.  The power to predict the future accurately.  The power to run experiments over and over again and always find the same result or else uncover a flaw in our current thoughts.  The power to use logic to solidify one’s beliefs and understanding of the world.  This power was intoxicating.  And I quickly became an addict.

Once I realized I had been wrong about one thing, I had to wonder what else I was mistaken about.  I started testing claims that I had heard, but never sought evidence for.  That penny and feather ended up changing the way I experienced the world and I was surprisingly ok with this. In fact, I greatly welcomed and enjoyed science’s intrusion into my life.  Of course, the hovercraft I was allowed to play with after the assembly may also have had something to do with my favorable impression of science.  Whatever the cause, I was motivated to develop the power held by the woman from the assembly. Perhaps soon I, too, will be able to tell the future.