Posts tagged antimatter

     You are hovering some planet in a galaxy far far away, uncertain whether it is made of matter or antimatter and hence whether or not it will be safe to land. The planet is inhabited by friendly aliens with whom you have made radio contact. They are very intelligent and understand you, and being advanced, know all about matter and antimatter.

     Naturally, they insist that they are made of matter; after all, it would be surprising if anyone chose to define their own stuff as ‘anti.’ How can we decide if their dictionary and ours coincide? What questions will unambiguously reveal whether they are made of the same stuff as us, or are anti-aliens?

     If matter and antimatter were always perfectly symmetrically counterpoised, there would be no way to settle the issue, other than gambling with a close approach of firing a tiny unmanned probe and seeing what  happens when it hits the atmosphere or anti-atmosphere. However, we know that there is an asymmetry, small but measurable, and that is what the electrically neutral variety of K mesons can reveal. They do so when they decay, producing a pion that is either positively or negatively charged accompanied by an electron or positron respectively. If matter and antimatter were perfect opposites, these two decays would also be precisely matched, the chance of each being the same. In reality, they are slightly different.

     The neutral K and anti-K are welded together in nature in such a way that they sometimes die quickly, but at other times live longer. The two possibilities are quite distinct and are known as the short- and long-lived versions. Each of these shows an asymmetry between matter and antimatter, but it is the long-lived one where the effect is biggest, they decay that leads to a positron being slightly more likely to happen than giving an electron: out of every two-thousand examples, on the average, 1,003 will give a positron and 997 give an electron. Now at last we have something to discuss with the alien.

     First, identify the K. It is no use giving its name, since the alien will certainly call it something else, but we can identify it by something we will agree about: its mass. It weighs in at slightly more than half the mass of a proton or antiproton and there are no other particles than can be confused with it. So tell the alien that we are interested in a particle whose mass is slightly more than half that of the massive particle that exists in the ‘nucleus’ at the center of the alien’s simplest atom, the proton in the hydrogen atom (or antiproton in an atom of antihydrogen.) That identifies the K.

     In addition to the neutral K, with no electric charge, there are also a K-plus and K-minus with positive or negative charge. So we much make sure that the alien and we are talking about the electrically neutral version. We must say that the property that holds the atom together is what we call ‘charge’ and that we are interested in the K that has no charge. The alien will be aware that this neutral K has two forms: one with a short life and one with a relatively long one. It is the latter that we will focus on.

     Now we come to the critical bit. In our world of matter, when the long-lived K decays into a pion and an electron or positron, it is the positron mode that is the most likely. So we ask the alien: ‘Is the lightweight particle that is produced most often in these decays the same as you find in your atoms, or is it the opposite?’ If the alien answers that it is the same, it is a positron, the alien is made of antimatter and we should look but not touch. If the alien replies that it is the opposite, an electron, then we are all made of matter and it is safe to land.

Antimatter, Frank Close

October 04, 2004|By Keay Davidson, Chronicle Science Writer

The U.S. Air Force is quietly spending millions of dollars investigating ways to use a radical power source — antimatter, the eerie “mirror” of ordinary matter — in future weapons.

The most powerful potential energy source presently thought to be available to humanity, antimatter is a term normally heard in science-fiction films and TV shows, whose heroes fly “antimatter-powered spaceships” and do battle with “antimatter guns.”

But antimatter itself isn’t fiction; it actually exists and has been intensively studied by physicists since the 1930s. In a sense, matter and antimatter are the yin and yang of reality: Every type of subatomic particle has its antimatter counterpart. But when matter and antimatter collide, they annihilate each other in an immense burst of energy.

During the Cold War, the Air Force funded numerous scientific studies of the basic physics of antimatter. With the knowledge gained, some Air Force insiders are beginning to think seriously about potential military uses — for example, antimatter bombs small enough to hold in one’s hand, and antimatter engines for 24/7 surveillance aircraft.

More cataclysmic possible uses include a new generation of super weapons — either pure antimatter bombs or antimatter-triggered nuclear weapons; the former wouldn’t emit radioactive fallout. Another possibility is antimatter- powered “electromagnetic pulse” weapons that could fry an enemy’s electric power grid and communications networks, leaving him literally in the dark and unable to operate his society and armed forces.

Following an initial inquiry from The Chronicle this summer, the Air Force forbade its employees from publicly discussing the antimatter research program. Still, details on the program appear in numerous Air Force documents distributed over the Internet prior to the ban.

These include an outline of a March 2004 speech by an Air Force official who, in effect, spilled the beans about the Air Force’s high hopes for antimatter weapons. On March 24, Kenneth Edwards, director of the “revolutionary munitions” team at the Munitions Directorate at Eglin Air Force Base in Florida was keynote speaker at the NASA Institute for Advanced Concepts (NIAC) conference in Arlington, Va.

In that talk, Edwards discussed the potential uses of a type of antimatter called positrons.

[Read More]

The first time I heard about the whole antimatter bomb thing, I must admit, I was horrified. I was disgusted with society and humanity, and I was furious. Of course, once I learned more about it and realized it’s significantly unlikely, my heart settled. Of course, the idea continues to be fascinating. I love antimatter.

When the space shuttle Endeavour lifts off one last time on Monday (May 16), it won’t just be the culmination of the orbiter’s career. It will also bring to fruition a 15-year, $2 billion quest to launch a device called the Alpha Magnetic Spectrometer to space.

The bus-size Alpha Magnetic Spectrometer (AMS) is an astrophysics experiment that will use a magnet to detect cosmic ray particles. These particles could include bizarre antimatter or other exotic species that scientists hope will shed light on some of the greatest mysteries of the universe, such as the puzzling dark matter thought to pervade space. [Video: Sifting Through the Cosmic Sand for Dark Matter]

For all its promise, AMS almost never got to fly. Originally scheduled to launch aboard the shuttle Columbia, the experiment lost its transportation after that orbiter was destroyed, along with its crew, in 2003. It took a vote by Congress to add one more shuttle mission before NASA retired its fleet to deliver AMS to the International Space Station.

SPACE.com spoke to AMS’s most ardent defender through its highs and lows, the experiment’s principal investigator Samuel Ting, a physicist at the Massachusetts Institute of Technology:

SPACE.com: What did you think when the shuttle mission to deliver AMS was canceled?

[Read More]

by Ken Kremer on May 10, 2011

Space Shuttle Endeavour is now set to launch on May16 at 8:56 a.m. EDT from Pad 39 A following launch scrub on April 29, 2011. Critical APU fuel line heaters in the aft section of the orbiter failed in the final hours of the countdown. This close up view was taken while I was standing next to the orbiter in March. Endeavour and crew will deliver the $2 Billion Alpha Magnetic Spectrometer to the International Space Station which seeks to unveil the Unknown and uncover the birth of the Universe. Credit: Ken Kremer

KENNEDY SPACE CENTER – NASA managers set May 16 as the new launch date for the final flight of Space Shuttle Endeavour after technicians completed work to rewire and retest a switchbox in the orbiters aft compartment. Shuttle managers ordered the repair work following a heater malfunction that forced NASA officials to call off the planned April 29 launch.

At a briefing for reporters today (May 9) at NASA’s Kennedy Space Center in Florida, Shuttle managers Mike Moses and Mike Leinbach announced that Endeavour’s last liftoff is now targeted for 8:56 a.m. EDT on Monday, May 16.

“Right now, we’re in good shape,” said Shuttle Launch Director Mike Leinbach.

“Endeavour’s looking good, the team is upbeat. I went to the meeting this morning and they’re ready to go. Hopefully, this time the heaters will work and we’ll be able to launch on time next Monday morning.”

[Read More]

17:52 03 May 2011 by Mark Buchanan

What can you do with a quarter of an hour? Write a few emails, cook rice – or store antimatter.

The team working on the Antihydrogen Laser Physics Apparatus (ALPHA) at the CERN particle physics laboratory near Geneva, Switzerland, have stored atoms of antihydrogen for 1000 seconds – roughly 10,000 times longer than before. This should help reveal if antimatter and matter are true mirror images.

Antihydrogen atoms are annihilated by hydrogen. The ALPHA team want to keep antimatter intact long enough to study it, so last year they worked out how to hold a cloud of antihydrogen in a magnetic trap. Not for long, though: collisions with trace gases would have either annihilated the anti-atoms or given them the energy to escape, so the team opened the trap after 170 milliseconds and observed the resulting annihilations, verifying that antimatter had been made.

Now they have repeated the experiment, this time waiting much longer before opening the trap. They also cooled the antiprotons used to create the antihydrogen much further, which lowered the energy of the antimatter, allowed more to be squeezed into the trap and raised the chance that some would last longer (arxiv.org/abs/1104.4982).

Antimatter’s life extension will permit experiments, such as checking whether antihydrogen occupies the same energy levels as hydrogen, “perhaps within the next few years”, says Daniel Kaplan of the Illinois Institute of Technology in Chicago, who is not on the ALPHA team.

existenceisfertile replied to your post: Antimatter mysteries: Can we make an anti-world?

Do you think that if they made a few different “anti” elements that more would naturally follow? I wonder if that might be how the universe “started,” or restarted.

In fractions of a second, antimatter particles and ultimately their atoms and potentially their molecules, annihilate and decompose into other elements and particles as antiparticles are very unstable. Consider one antiparticle: it’s surrounded by our every day experience of normal matter, that which antimatter annihilates with instantaneously. To maintain antimatter, even one particle, is very tedious. Using magnetic fields, they sustain them in a vacuum, but in a continuous path so they don’t touch the walls of the vacuum (since it is made of regular matter.) CERN goes through a variety of steps in maintaining antimatter to produce an antimatter factory, which you can read about here.

So, going back to your original question, as far as I’m concerned, the only way molecules would have the possibility of being made, would be in a vacuum, in a strong magnetic field. As for life to be created in such conditions, I’ll leave it up to your discretion to decide an opinion on whether life could flourish in such extreme conditions or not.

PS: If you’re interested in antimatter, please read Antimatter by Frank Close. I’ve put up a review here. :)

22 April 2011 by Mark Buchanan

AN ISOLATED proton has been trapped and coaxed into revealing the strength of its magnetism, a feat that could help investigate an enduring question about antimatter.

Many subatomic particles act like tiny magnets, with their strength dubbed their “g-factor”. Prior attempts to measure the proton’s g-factor were not precise as they were restricted to probing protons in atoms, where orbiting electrons disguise the proton’s properties.

Now physicists led by Jochen Walz at the University of Mainz in Germany have managed to isolate a single proton and measure its g-factor. They start by shooting electrons at a substance: the impact releases protons, which can be trapped using a magnet. Next, the researchers slowly let the protons escape until just one is left. The magnet causes the lone proton to “precess” like a spinning top, at a frequency that depends on its g-factor. The researchers deduced this frequency using radio waves that flipped the orientation of the proton’s magnet only when their frequency matched the precession frequency (arxiv.org/abs/1104.1206v1).

This in itself did not yield a more precise value for the g-factor than previously, but it will if the proof-of-principle experiment is repeated using a higher-precision trap, says Wolfgang Quint, a team member from the Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany.

The technique could also be used to measure the g-factor of antiprotons. It is thought that antimatter is a mirror image of matter - exactly the same but with an opposite charge. If this is true, then the g-factors of the proton and antiproton should be identical.

11:50 30 April 2009 by Amanda Gefter

At the moment physicists are having enough difficulty just taming antihydrogen, the simplest possible anti-atom. Can we ever expect them to make antihelium, and then organic antimolecules made from anticarbon and a whole anti-periodic table, too?

The problem here is that every anti-atom has to be built one subatomic antiparticle at a time. For example, if you want to make antideuterium - like antihydrogen, but with an added antineutron - you first have to make the antineutron. Antineutrons are neutral, making them impossible to steer in the conventional way with electromagnetic fields, so you just have to make great numbers of them and hope that for every million or so antineutrons you make, one ends up in the right place to make an antideuterium atom. “And for every further antineutron or antiproton you add, you lose another factor of a million,” says Michael Doser, spokesman for CERN’s AEGIS experiment studying the properties of antimatter.

While no one’s cracked that problem yet, one experiment at CERN is making use of a neat short cut to at least make something other than antihydrogen. ASACUSA has created atoms of “antiprotonic helium”, in which one of the electrons orbiting a helium nucleus is replaced by an antiproton. By studying the light spectra emitted by this composite matter-antimatter atom, the electrical and magnetic properties of the antiproton can be measured with great precision - and compared with those of a regular proton.

As for our chances of making anything more complex, Frank Close, a particle physicist at the University of Oxford, is pessimistic, saying it will take a billion years, give or take. “It depends on how long the human race lasts,” he says. It seems that our best bet for spying more exotic elements of the anti-periodic table is to look up at the sky - and hope that somewhere antistars are busy churning them out for us.

[Read More]

NASA is ruling out any chance of a Mother’s Day launch for the shuttle Endeavour, saying that it will take until at least May 10 to resolve a heater glitch and get the spaceship ready for its last flight.

Just a day ago, mission managers said the launch wouldn’t happen before May 8, which is Mother’s Day. Today, they took a fresh look at the schedule and said they’d need even more time to test the switchbox and wiring in one of Endeavour’s auxiliary power units.

A problem with the wiring, which involves a heater for the shuttle’s hydraulic system, forced NASA’s managers to call off the countdown for a launch on Friday. Hundreds of thousands of visitors, including President Barack Obama and his family, were hoping to see the shuttle program’s second-to-last liftoff.

Here’s today’s mission status update:

“NASA space shuttle and International Space Station managers met Monday and determined that Tuesday, May 10, is the earliest Endeavour could be launched on the STS-134 mission. That date is success-oriented based on preliminary schedules to replace a faulty Load Control Assembly (LCA) box in the orbiter’s aft compartment.

“Plans are for managers to reconvene Friday to determine a more definite launch date after the box is removed and replaced and the retest of systems has been completed.

“Space Shuttle Program managers adjusted the date after further evaluating the schedules to change out the box and retest the nine shuttle systems associated with the controller. That work would be followed by the standard closeout of the aft compartment before proceeding into the launch countdown.

“Sunday night and Monday, technicians at NASA’s Kennedy Space Center’s Launch Pad 39A conducted additional testing of systems associated with LCA-2, including testing the box itself, which is expected to be removed late Monday or early Tuesday and replaced with an existing spare.

“Managers will continue to evaluate the repair process and make any additional adjustments before scheduling Endeavour’s next launch attempt for its STS-134 mission to the International Space Station.

“The STS-134 crew is back in Houston and remains in quarantine throughout as it slowly adjusts its wake and sleep schedule to match the new launch time. While at NASA’s Johnson Space Center, the crew will conduct a launch and landing simulation with its ascent and entry flight control team based in Mission Control, before returning to Florida for the launch countdown.”

[Read More]