Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Eclipses again prove key for Einstein

04.07.2008
Observations of unique dead star system show effects of general relativity

Eclipses in a unique system of two dead stars, called pulsars, has shown that one of the pair is ‘wobbling’ in space - just like a spinning top. The effect, called precession, is precisely as predicted by Albert Einstein and is thus a new and exciting confirmation of his theory.

The discovery was made by researchers at The University of Manchester's Jodrell Bank Centre for Astrophysics - working as part of an international team of astronomers - and will be published on 4 July in the journal Science.

The star system contains two pulsars which were formed when a pair of massive stars exploded and their cores collapsed to create objects whose mass is greater than that of our Sun, but compressed to the size of a city like Manchester. They are spinning at staggering speeds and emit powerful beams of radio waves which sweep across our radio-telescopes like cosmic lighthouses producing regular pulses of energy - hence their name, pulsars. The pulsar pair, PSR J0737-3039A/B, is the only known system in our galaxy where two pulsars are locked into such close orbit around one another - the entire system could fit inside our Sun.

Prof Michael Kramer of The University of Manchester explained: "We discovered the double pulsar in 2003 using the Parkes Radio Telescope in Australia and have since been carefully timing the arrival of its pulses using several telescopes, including the Lovell Telescope at Jodrell Bank, and the Green Bank Telescope in the US. It has proved to be the best test we have for the predictions of Einstein's theory of gravity, general relativity".

René Breton of McGill University added: "The double pulsar creates ideal conditions for testing general relativity's predictions because the larger and the closer two massive objects are to one another, the more important relativistic effects are.

"Binary pulsars are the best place to test general relativity in a strong gravitational field," agreed Prof Victoria Kaspi, also of McGill University. "Einstein predicted that, in such a field, the axis about which an object rotates will precess - or change direction slowly as the pulsar orbits around its companion. Imagine a spinning top tilted over slightly to one side - the spin axis wobbles.

"Pulsars are too small and too distant to allow us to observe this wobble directly", Breton explained. “However, as they orbit each other every 145 minutes, each passes in front of the other and the astronomers soon realized they could measure the direction of the pulsar's spin axis as the highly magnetized region surrounding it blocks the radio waves being emitted from the other. After patiently collecting the radio pulses over the past four years, they have now determined that its spin axis precesses exactly as Einstein predicted.”

Breton explained that even though spin precession has been observed in Earth's solar system, differences between general relativity and alternative theories of gravity might only become apparent in extremely powerful gravity fields such as those near pulsars.

"So far, Einstein's theory has passed all the tests that have been conducted, including ours,” said Breton. “We can now say that if anyone wants to propose an alternative theory of gravity in the future, it must agree with the results that we have obtained here.

"I think that if Einstein were alive today, he would have been absolutely delighted with these results," concluded Prof Kramer. "Not only because it confirms his theory, but also because of the novel and amazing way the confirmation has come about."

Alex Waddington | alfa
Further information:
http://www.jb.man.ac.uk/news/pulsareclipse/

More articles from Physics and Astronomy:

nachricht MSU astronomers discovered supermassive black hole in an ultracompact dwarf galaxy
14.08.2018 | Lomonosov Moscow State University

nachricht ASU astrophysicist helps discover that ultrahot planets have starlike atmospheres
13.08.2018 | Arizona State University

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: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

'Building up' stretchable electronics to be as multipurpose as your smartphone

14.08.2018 | Information Technology

During HIV infection, antibody can block B cells from fighting pathogens

14.08.2018 | Life Sciences

First study on physical properties of giant cancer cells may inform new treatments

14.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>