Universe Today » Physics

World-wide Campaign Sheds New Light on Nature's "LHC"

Jean Tate — Thu, 11 Mar 2010 21:52:42 +0000

Recent observations of blazar jets require researchers to look deeper into whether current theories about jet formation and motion require refinement. This simulation, courtesy of Jonathan McKinney (KIPAC), shows a black hole pulling in nearby matter (yellow) and spraying energy back out into the universe in a jet (blue and red) that is held together by magnetic field lines (green).

In a manner somewhat like the formation of an alliance to defeat Darth Vader's Death Star, more than a decade ago astronomers formed the Whole Earth Blazar Telescope consortium to understand Nature's Death Ray Gun (a.k.a. blazars). And contrary to its at-death's-door sounding name, the GASP has proved crucial to unraveling the secrets of how Nature's "LHC" works.

"As the universe's biggest accelerators, blazar jets are important to understand," said Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) Research Fellow Masaaki Hayashida, corresponding author on the recent paper presenting the new results with KIPAC Astrophysicist Greg Madejski. "But how they are produced and how they are structured is not well understood. We're still looking to understand the basics."

Blazars dominate the gamma-ray sky, discrete spots on the dark backdrop of the universe. As nearby matter falls into the supermassive black hole at the center of a blazar, "feeding" the black hole, it sprays some of this energy back out into the universe as a jet of particles.
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© Jean Tate for Universe Today, 2010. | Permalink | 35 comments | Add to del.icio.us
Post tags: blazars, jets, supermassive black holes

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Small Asteroids, Bread Flour, and a Dutch Physicist's 150-year Old Theory

Jean Tate — Sun, 28 Feb 2010 01:15:09 +0000

Itokawa, a dusty asteroid (Credit: JAXA)

No, it's not the Universe Puzzle No. 3; rather, it's an intriguing result from recent work into the strange shapes and composition of small asteroids.

Images sent back from space missions suggest that smaller asteroids are not pristine chunks of rock, but are instead covered in rubble that ranges in size from meter-sized boulders to flour-like dust. Indeed some asteroids appear to be up to 50% empty space, suggesting that they could be collections of rubble with no solid core.

But how do these asteroids form and evolve? And if we ever have to deflect one, to avoid the fate of the dinosaurs, how to do so without breaking it up, and making the danger far greater?

Johannes Diderik van der Waals (1837-1923), with a little help from Daniel Scheeres, Michael Swift, and colleagues, to the rescue.
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ESA's Tough Choice: Dark Matter, Sun Close Flyby, Exoplanets (Pick Two)

Jean Tate — Sun, 21 Feb 2010 01:30:45 +0000

Key questions relevant to fundamental physics and cosmology, namely the nature of the mysterious dark energy and dark matter (Euclid); the frequency of exoplanets around other stars, including Earth-analogs (PLATO); take the closest look at our Sun yet possible, approaching to just 62 solar radii (Solar Orbiter) … but only two! What would be your picks?

These three mission concepts have been chosen by the European Space Agency's Science Programme Committee (SPC) as candidates for two medium-class missions to be launched no earlier than 2017. They now enter the definition phase, the next step required before the final decision is taken as to which missions are implemented.
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Does Zonal Swishing Play a Part in Earth's Magnetic Field Reversals?

Jean Tate — Sat, 20 Feb 2010 17:24:27 +0000

Zonal swishing in the Earth's outer core (Credit: Akira Kageyama, Kobe University)

Why does the Earth's magnetic field 'flip' every million years or so? Whatever the reason, or reasons, the way the liquid iron of the Earth's outer core flows – its currents, its structure, its long-term cycles – is important, either as cause, effect, or a bit of both.

The main component of the Earth's field – which defines the magnetic poles – is a dipole generated by the convection of molten nickel-iron in the outer core (the inner core is solid, so its role is secondary; remember that the Earth's core is well above the Curie temperature, so the iron is not ferromagnetic).

But what about the fine structure? Does the outer core have the equivalent of the Earth's atmosphere's jet streams, for example? Recent research by a team of geophysicists in Japan sheds some light on these questions, and so hints at what causes magnetic pole flips.
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© Jean Tate for Universe Today, 2010. | Permalink | 8 comments | Add to del.icio.us
Post tags: earth magnetic field, Earth's outer core, geomagnetic reversal, planet earth

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Einstein's General Relativity Tested Again, Much More Stringently

Jean Tate — Fri, 19 Feb 2010 17:21:54 +0000

Einstein, whose theory of general relativity has just passed another test

This time it was the gravitational redshift part of General Relativity; and the stringency? An astonishing better-than-one-part-in-100-million!

How did Steven Chu (US Secretary of Energy, though this work was done while he was at the University of California Berkeley), Holger Müler (Berkeley), and Achim Peters (Humboldt University in Berlin) beat the previous best gravitational redshift test (in 1976, using two atomic clocks – one on the surface of the Earth and the other sent up to an altitude of 10,000 km in a rocket) by a staggering 10,000 times?

By exploited wave-particle duality and superposition within an atom interferometer!
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© Jean Tate for Universe Today, 2010. | Permalink | 5 comments | Add to del.icio.us
Post tags: General Relativity, redshift, Theory of General Relativity

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Universe to WMAP: ΛCDM Rules, OK?

Jean Tate — Mon, 08 Feb 2010 08:47:12 +0000

Temperature and polarization, CMB hot and cold spots (Credit: NASA/WMAP Science Team)

The Wilkinson Microwave Anisotropy Probe (WMAP) science team has finished analyzing seven full years' of data from the little probe that could, and once again it seems we can sum up the universe in six parameters and a model.

Using the seven-year WMAP data, together with recent results on the large-scale distribution of galaxies, and an updated estimate of the Hubble constant, the present-day age of the universe is 13.75 (plus-or-minus 0.11) billion years, dark energy comprises 72.8% (+/- 1.5%) of the universe's mass-energy, baryons 4.56% (+/- 0.16%), non-baryonic matter (CDM) 22.7% (+/- 1.4%), and the redshift of reionization is 10.4 (+/- 1.2).

In addition, the team report several new cosmological constraints – primordial abundance of helium (this rules out various alternative, 'cold big bang' models), and an estimate of a parameter which describes a feature of density fluctuations in the very early universe sufficiently precisely to rule out a whole class of inflation models (the Harrison-Zel'dovich-Peebles spectrum), to take just two – as well as tighter limits on many others (number of neutrino species, mass of the neutrino, parity violations, axion dark matter, …).
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© Jean Tate for Universe Today, 2010. | Permalink | 7 comments | Add to del.icio.us
Post tags: big bang theory, CMB, Inflation Theory, WMAP

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Nuclear Fusion Power Closer to Reality Say Two Separate Teams

Nancy Atkinson — Thu, 28 Jan 2010 19:31:26 +0000

Nuclear fusion. Credit: Lancaster University

For years, scientists have been trying to replicate the type of nuclear fusion that occurs naturally in stars in laboratories here on Earth in order to develop a clean and almost limitless source of energy. This week, two different research teams report significant headway in achieving inertial fusion ignition—a strategy to heat and compress a fuel that might allow scientists to harness the intense energy of nuclear fusion. One team used a massive laser system to test the possibility of heating heavy hydrogen atoms to ignite. The second team used a giant levitating magnet to bring matter to extremely high densities — a necessary step for nuclear fusion.
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© nancy for Universe Today, 2010. | Permalink | 31 comments | Add to del.icio.us
Post tags: Nuclear fusion, Physics, Science

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Physicists Tie Beam of Light into Knots

Nancy Atkinson — Mon, 18 Jan 2010 18:23:46 +0000

The colored circle represents the hologram, out of which the knotted optical vortex emerges. Credit: University of Bristol

Imagine taking a beam of light and tying it in knots like a piece of string. Hard to fathom? Well, a group of physicists from the UK have achieved this remarkable feat, and they say understanding how to control light in this way has important implications for laser technology used in wide a range of industries.
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New Pulsar "Clocks" Will Aid Gravitational Wave Detection

Ryan Anderson — Tue, 05 Jan 2010 19:30:24 +0000

This illustration shows a pulsar's magnetic field (blue) creates narrow beams of radiation (magenta). Image credit: NASA

How do you detect a ripple in space-time itself? Well, you need hundreds of precision clocks distributed throughout the galaxy, and the Fermi gamma ray telescope has given astronomers a new way to find them.

The "clocks" in question are actually millisecond pulsars – city-sized, sun-massed stars of ultradense matter that spin hundreds of times per second. Due to their powerful magnetic fields, pulsars emit most of their radiation in tightly focused beams, much like a lighthouse. Each spin of the pulsar corresponds to a "pulse" of radiation detectable from Earth. The rate at which millisecond pulsars pulse is extremely stable, so they serve as some of the most reliable clocks in the universe.

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© rande for Universe Today, 2010. | Permalink | 21 comments | Add to del.icio.us
Post tags: AAS, Gamma rays, Gravitational Waves, Pulsars, radio telescopes

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LHC Officially Becomes Most Powerful Accelerator

Nicholos Wethington — Tue, 01 Dec 2009 06:29:00 +0000

Well, they've done it: at 2028 GMT, 29 November 2009 the Large Hadron Collider officially became the most powerful particle accelerator ever built by humans. One of the proton beams in the LHC was powered up to 1.05 teraelectron volts (TeV) at that time, and three hours later both of the beams were powered to 1.18 TeV. This breaks the previous record held by the Fermilab accelerator in Chicago, which has held the record of .98 TeV since 2001.(...)
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First Collisions for the LHC

Nancy Atkinson — Mon, 23 Nov 2009 21:05:07 +0000

Screens showing two beams in the LHC. Credit: CERN

Two beams circulated simultaneously inside the Large Hadron Collider for the first time today, allowing for the first proton-proton collisions to take place. “It’s a great achievement to have come this far in so short a time,” said CERN Director General Rolf Heuer. “But we need to keep a sense of perspective – there’s still much to do before we can start the LHC physics program.”
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Large Hadron Collider Could Re-Start This Weekend

Nancy Atkinson — Thu, 19 Nov 2009 23:24:42 +0000

The Large Hadron Collider (LHC) could be re-started on this Saturday morning CERN officials said. Engineers are preparing to send a beam of sub-atomic particles around the 27km-long circular tunnel, which has been shut down since an accident in September 2008. Scientists hope to create conditions similar to those present moments after the Big Bang in search of the elusive Higgs particle to shed light on fundamental questions about the universe.
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Physicist Vitaly Ginzburg Dies at age 93

Nicholos Wethington — Mon, 09 Nov 2009 20:11:36 +0000

Vitaly Ginzburg, a Russian physicist and Nobel laureate, died yesterday of cardiac arrest. He was 93 years old. Ginzburg shared the 2003 Nobel Prize in physics for his work on superconductors, but contributed to many other fields of study, including quantum theory, astrophysics, radio-astronomy and diffusion of cosmic radiation in the Earth's atmosphere. In addition, he is known for his contributions to the development of the Russian hydrogen bomb in the 1950s, for which he received the Stalin Prize.(...)
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Bread Dropped By Bird Causes Problems for LHC

Nancy Atkinson — Fri, 06 Nov 2009 15:52:44 +0000

The complexity of the Large Hadron Collider (CERN/LHC/GridPP)

Yes, this headline appears to be true. A bird dropping a piece of bread onto outdoor machinery has been blamed for a technical fault at the Large Hadron Collider (LHC) this week which saw significant overheating on parts of the accelerator. The LHC was not operational at the time of the incident, but the spike produced so much heat that had the beam been on, automatic safety detectors would have shut down the machine. This would put the LHC out of action for a few days while it was restarted, but there would be no repeat of the catastrophic damage suffered last September. That's when an electrical connection in the circuit itself failed violently, causing a massive liquid-helium leak and subsequent damage along hundreds of meters of magnets.

Hmm. The idea of a time-traveling Higgs boson coming back to prevent its own discovery is seeming less and less far fetched!
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Solving the Mystery of Cosmic Rays' Origins

Nancy Atkinson — Mon, 02 Nov 2009 18:02:37 +0000

What accelerates cosmic rays to nearly the speed of light? Astronomer have pondered that question for nearly 100 years, and now new evidence supports a theory held for two decades that cosmic rays likely are powered by exploding stars and stellar winds. "This discovery has been predicted for almost 20 years, but until now no instrument was sensitive enough to see it," said Wystan Benbow, an astrophysicist at the Smithsonian Astrophysical Observatory who coordinated this project for the Very Energetic Radiation Imaging Telescope Array System (VERITAS) collaboration.
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Particles Injected into Large Hadron Collider

Nancy Atkinson — Wed, 28 Oct 2009 13:39:48 +0000

The first ion beam entering point 2 of the LHC, just before the ALICE detector (23 October 2009). Credit: CERN

The Large Hadron Collider reached an important milestone last weekend as a beam of ions was injected into the clockwise beam pipe. This is the first time particles have been inside the collider since September, 2008 when physicists were forced to shut down the system because of a massive failure. According to a CERN press release, lead ions were placed in the clockwise beam pipe on Friday October 23, but did not travel along the whole circumference of the LHC. CERN officials still hope for a restart in 2009, with the first circulating beam likely to be injected in mid-November, and the first high energy collisions occurring around mid-December.
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Your CCD Camera Just Won a Nobel Prize

Nancy Atkinson — Tue, 06 Oct 2009 14:14:23 +0000

Charged Coupled Devices (CCD) for Ultra-Violet and Visible Detection. Credit: NASA

Well, actually, the people who invented the first successful imaging technology using a digital sensor, called a CCD (Charge-Coupled Device), have been awarded the Nobel Prize in Physics. In 1969 Willard S. Boyle and George E. Smith came up with the idea "from their own heads," Smith said, and CCDs revolutionized photography, as light could now be captured electronically instead of on film, and became an irreplaceable tool in astronomy, providing new possibilities to visualize the previously unseen. The device also made it possible for amateur astronomers to rival the professionals in terms of quality astrophotography. CCD technology is also used in many medical applications, e.g. imaging the inside of the human body, both for diagnostics and for microsurgery. Sharing the prize with Boyle and Smith is Charles K. Kao, who in 1966 made a discovery that led to a breakthrough in fiber optics.

Both achievements helped shape the foundations of today’s networked societies.

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New Way to Measure Curvature of Space Could Unite Gravity Theory

Nancy Atkinson — Tue, 01 Sep 2009 23:10:10 +0000

The curvature of space due to gravity.

Einstein's general theory of relativity describes gravity in terms of the geometry of both space and time. Far from a source of gravity, such as a star like our sun, space is "flat" and clocks tick at their normal rate. Closer to a source of gravity, however, clocks slow down and space is curved. But measuring this curvature of space is difficult. However, scientists have now used a continent-wide array of radio telescopes to make an extremely precise measurement of the curvature of space caused by the Sun's gravity. This new technique promises to contribute greatly in studying quantum physics.
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What If There Is Only One Universe?

Brian Ventrudo — Thu, 04 Jun 2009 23:28:24 +0000

When it comes to universes, perhaps one is enough after all.

Many theories in physics and cosmology require the existence of alternate, or parallel, universes. But Dr. Lee Smolin of the Perimeter Institute for Theoretical Physics in Waterloo, Canada, explains the flaws of theories that suggest our universe is just one of many, and which also perpetuate the notion that time does not exist. Smolin, author of the bestselling science book 'The Trouble with Physics' and a founding member of the Perimeter Institute, explains his views in the June issue of Physics World.

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Is Everything Made of Mini Black Holes?

Nancy Atkinson — Fri, 15 May 2009 05:23:00 +0000

In 1971 physicist Stephen Hawking suggested that there might be "mini" black holes all around us that were created by the Big Bang. The violence of the rapid expansion following the beginning of the Universe could have squeezed concentrations of matter to form miniscule black holes, so small they can't even be seen in a regular microscope. But what if these mini black holes were everywhere, and in fact, what if they make up the fabric of the universe? A new paper from two researchers in California proposes this idea.
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Is a Nearby Object in Space Beaming Cosmic Rays at Earth?

Nancy Atkinson — Mon, 04 May 2009 18:15:05 +0000

Fermi Telescope. Credit: NASA

Data from several different space and ground based observatories imply the presence of a nearby object that is beaming cosmic rays our way. Scientists with the Fermi Space Telescope say an unknown pulsar may be close by, sending electrons and positrons towards Earth. Or another more exotic explanation is that the particles could come from the annihilation of dark matter. But whatever it is, the source is relatively close, surely in our galaxy. "If these particles were emitted far away, they’d have lost a lot of their energy by the time they reached us," said Luca Baldini, a Fermi collaborator.
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Do We Need a New Theory of Gravitation?

Nancy Atkinson — Wed, 22 Apr 2009 00:59:33 +0000

Draco satellite dwarf galaxy. Credit: Mischa Schirmer, University of Bonn

A group of physicists say that the distribution of satellite galaxies that orbit the Milky Way, as well as the apparent dark matter within them, presents a direct challenge to Newton’s theory of gravitation, as the galaxies are not where they should be. “There is something odd about their distribution,” said Professor Pavel Kroupa from the University of Bonn in Germany. “They should be uniformly arranged around the Milky Way, but this is not what we found.” Standard cosmological models predict the presence of hundreds of these companions around most of the larger galaxies, but up to now only 30 have been observed around the Milky Way. The physicists say that Newton's theory of gravitation should be modified.
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Hawking Update: Condition Improved

Nancy Atkinson — Tue, 21 Apr 2009 15:12:25 +0000

Professor Stephen Hawking in 2006. Credit: Wikipedia

Physicist/mathematician Stephen Hawking has improved after spending the night at a hospital near his home in Cambridge, England, and the 67-year-old's condition was described as "comfortable." Hawking's first wife, Jane, was quoted that she believed his illness was no longer life-threatening. A spokesperson for Cambridge University, where Prof Hawking holds the post of Lucasian Professor of Mathematics, said that he would be kept in hospital for observation. "He is comfortable and his family is looking forward to him making a full recovery," said Gregory Hayman. "He has had a good night but will be kept in at Addenbrooke's Hospital for observation. He is showing signs of improvement."
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Physicist Hawking Gravely Ill

Nancy Atkinson — Mon, 20 Apr 2009 16:19:15 +0000

Stephen Hawking. Credit: NASA

Famed theoretical physicist Stephen Hawking has been rushed to a hospital and is seriously ill. Cambridge University released information today that Hawking has been fighting a chest infection for several weeks, and was taken to a hospital in Cambridge."Professor Hawking is very ill," said Gregory Hayman, the university's head of communications. "He is undergoing tests. He has been unwell for a couple of weeks." Hawking, 67, is well known for his work on black holes, and has remained active despite being diagnosed at 21 with ALS, (amyotrophic lateral sclerosis), an incurable degenerative disorder also known as Lou Gehrig's disease.
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Universe Today » Physics

World-wide Campaign Sheds New Light on Nature's "LHC"

Small Asteroids, Bread Flour, and a Dutch Physicist's 150-year Old Theory

ESA's Tough Choice: Dark Matter, Sun Close Flyby, Exoplanets (Pick Two)

Does Zonal Swishing Play a Part in Earth's Magnetic Field Reversals?

Einstein's General Relativity Tested Again, Much More Stringently

Universe to WMAP: ΛCDM Rules, OK?

Nuclear Fusion Power Closer to Reality Say Two Separate Teams

Physicists Tie Beam of Light into Knots

New Pulsar "Clocks" Will Aid Gravitational Wave Detection

LHC Officially Becomes Most Powerful Accelerator

First Collisions for the LHC

Large Hadron Collider Could Re-Start This Weekend

Physicist Vitaly Ginzburg Dies at age 93

Bread Dropped By Bird Causes Problems for LHC

Solving the Mystery of Cosmic Rays' Origins

Particles Injected into Large Hadron Collider

Top Questions That Keep Physicists Awake at Night

Your CCD Camera Just Won a Nobel Prize

New Way to Measure Curvature of Space Could Unite Gravity Theory

What If There Is Only One Universe?

Is Everything Made of Mini Black Holes?

Is a Nearby Object in Space Beaming Cosmic Rays at Earth?

Do We Need a New Theory of Gravitation?

Hawking Update: Condition Improved

Physicist Hawking Gravely Ill