Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Part-time pulsar yields new insight into inner workings of cosmic clocks

03.03.2006


Astronomers using the 76-m Lovell radio telescope at the University of Manchester’s Jodrell Bank Observatory have discovered a very strange pulsar that helps explain how pulsars act as ‘cosmic clocks’ and confirms theories put forward 37 years ago to explain the way in which pulsars emit their regular beams of radio waves - considered to be one of the hardest problems in astrophysics. Their research, now published in Science Express, reveals a pulsar that is only ‘on’ for part of the time. The strange pulsar is spinning about its own axis and slows down 50% faster when it is ‘on’ compared to when it is ‘off’.



Pulsars are dense, highly magnetized neutron stars that are born in a violent explosion marking the death of massive stars. They act like cosmic lighthouses as they project a rotating beam of radio waves across the galaxy. Dr. Michael Kramer explains, "Pulsars are a physicist’s dream come true. They are made of the most extreme matter that we know of in the Universe, and their highly stable rotation makes them super-precise cosmic clocks. But, embarrassingly, we do not know how these clocks work. This discovery goes a long way towards solving this problem."

The research team, led by Dr. Michael Kramer, found a pulsar that is only periodically active. It appears as a normal pulsar for about a week and then “switches off” for about one month before emitting pulses again. The pulsar, called PSR B1931+24, is unique in this behaviour and affords astronomers an opportunity to compare its quiet and active phases. As it is quiet the majority of the time, it is difficult to detect, suggesting that there may be many other similar objects that have, so far, escaped detection.


Prof. Andrew Lyne points out that, “After the discovery of pulsars, theoreticians proposed that strong electric fields rip particles out of the neutron star surface into a surrounding magnetised cloud of plasma called the magnetosphere. But, for nearly 40 years, there had been no way to test whether our basic understanding was correct."

The University of Manchester astronomers were delighted when they found that this pulsar slows down more rapidly when the pulsar is on than when it is off. Dr. Christine Jordan points out the importance of this discovery, "We can clearly see that something hits the brakes when the pulsar is on.”

This breaking mechanism must be related to the radio emission and the processes creating it and the additional slow-down can be explained by a wind of particles leaving the pulsar’s magnetosphere and carrying away rotational energy. “Such a braking effect of the pulsar wind was expected but now, finally, we have observational evidence for it” adds Dr Duncan Lorimer.

The amount of braking can be related to the number of charges leaving the pulsar magnetosphere. Dr. Michael Kramer explains their surprise when it was found that the resulting number was within 2% of the theoretical predictions. "We were really shocked when we saw these numbers on our screens. Given the pulsar’s complexity, we never really expected the magnetospheric theory to work so well."

Prof. Andrew Lyne summarized the result: "It is amazing that, after almost 40 years, we have not only found a new, unusual, pulsar phenomenon but also a very unexpected way to confirm some fundamental theories about the nature of pulsars."

Julia Maddock | alfa
Further information:
http://www.pparc.ac.uk

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>