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Space-time is swirling around a dead star, proving Einstein right again

Artist’s illustration of Lense-Thirring frame-dragging resulting from a rotating white dwarf in the PSR J1141-6545 binary star system.
Artist’s illustration of Lense-Thirring frame-dragging resulting from a rotating white dwarf in the PSR J1141-6545 binary star system.
(Image: © Mark Myers, ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav))

The way the fabric of space and time swirls in a cosmic whirlpool around a dead star has confirmed yet another prediction from Einstein's theory of general relativity, a new study finds.

That prediction is a phenomenon known as frame dragging, or the Lense-Thirring effect. It states that space-time will churn around a massive, rotating body. For example, imagine Earth were submerged in honey. As the planet rotated, the honey around it would swirl — and the same holds true with space-time.

Satellite experiments have detected frame dragging in the gravitational field of rotating Earth, but the effect is extraordinarily small and, therefore, has been challenging to measure. Objects with greater masses and more powerful gravitational fields, such as white dwarfs and neutron stars, offer better chances to see this phenomenon.

Related: Albert Einstein: Biography, theories and quotes

Scientists focused on PSR J1141-6545, a young pulsar about 1.27 times the mass of the sun. The pulsar is located 10,000 to 25,000 light-years from Earth in the constellation Musca (the fly), which is near the famous Southern Cross constellation. 

A pulsar is a fast-spinning neutron star that emits radio waves along its magnetic poles. (Neutron stars are corpses of stars that died in catastrophic explosions known as supernovas; the gravity of these remnants is powerful enough to crush protons together with electrons to form neutrons.)

PSR J1141-6545 circles a white dwarf with a mass about the same as the sun's. White dwarfs are the superdense Earth-size cores of dead stars that are left behind after average-size stars have exhausted their fuel and shed their outer layers. Our sun will end up as a white dwarf one day, as will more than 90% of all stars in our galaxy.

The pulsar orbits the white dwarf in a tight, fast orbit less than 5 hours long, hurtling through space at about 620,000 mph (1 million km/h), with a maximum separation between the stars barely larger than the size of our sun, study lead author Vivek Venkatraman Krishnan, an astrophysicist at the Max Planck Institute for Radio Astronomy in Bonn, Germany, told Space.com.

The researchers measured when pulses from the pulsar arrived at Earth to an accuracy within 100 microseconds over a period of nearly 20 years, using the Parkes and UTMOST radio telescopes in Australia. This allowed them to detect a long-term drift in the way the pulsar and white dwarf orbit each other.

After eliminating other possible causes of this drift, the scientists concluded that it was the result of frame dragging: The way the rapidly spinning white dwarf pulls on space-time has caused the pulsar's orbit to change its orientation slowly over time. Based on the level of frame dragging, the researchers calculated that the white dwarf whirls on its axis about 30 times an hour.

Previous research suggested that the white dwarf formed before the pulsar in this binary system. One prediction of such theoretical models is that, before the pulsar-forming supernova occurred, the progenitor of the pulsar shed nearly 20,000 Earth masses' worth of matter onto the white dwarf over the course of about 16,000 years, boosting its rate of spin. 

"Systems like PSR J1141-6545, where the pulsar is younger than the white dwarf, are quite rare," Venkatraman Krishnan said. The new study "confirms a long-standing hypothesis of how this binary system came to be, something that was proposed over two decades ago."

The researchers noted that they used frame dragging to yield insight into the rotating star that caused it. In the future, they said, they can use a similar method to analyze binary neutron stars to learn more about their internal composition, "which, even after more than 50 years of observing them, we do not yet have a handle on," Venkatraman Krishnan said. "The density of matter inside a neutron star far exceeds what can be achieved in a lab, so there is a wealth of new physics to be learnt by using this technique to double neutron-star systems."

The scientists detailed their findings online today (Jan. 30)  in the journal Science.

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  • Anonymous010
    PSR J1141-6545 circles a white dwarf with a mass about the same as the sun's.

    The pulsar orbits the white dwarf in a tight, fast orbit

    You guys might want to rephrase the above lines in the article. The white dwarf is less massive (1.02 solar masses) than the pulsar (1.27 solar masses). Technically, both objects in that system orbit the system's barycenter (center of mass), but if you want to say one orbits the other, then it should be the white dwarf orbits the pulsar, since the pulsar would be the dominant mass in that system.
    Reply
  • Din Rash
    Anonymous010 said:
    You guys might want to rephrase the above lines in the article. The white dwarf is less massive (1.02 solar masses) than the pulsar (1.27 solar masses). Technically, both objects in that system orbit the system's barycenter (center of mass), but if you want to say one orbits the other, then it should be the white dwarf orbits the pulsar, since the pulsar would be the dominant mass in that system.
    In theory of relativity everything is relative. Still you can say that sun and moon orbiting Earth while other planets in system orbiting sun - it so easy ;)
    Reply
  • HPB
    "It states that space-time will churn around a massive, rotating body. "
    Well, maybe it's the other way around.... a massive body (Galaxy...) rotates because space time rotates around it. Cause and effect reversed.
    Our matter-centric world is only a few percent of the universe, Why do we always jump to the conclusion that IT "gives the beat", whilst it may be really the other way around.
    It's more likely to be at the mercy of much larger forces in the universe.
    Reply
  • Galaxyhunter
    The article said that they ruled out everything else so it must be frame dragging. However, it seems to me that the dragging effect is caused by gravitational pull of one body on another. There could also be a magnetic field pulling one from another.
    Reply
  • rod
    Admin said:
    The way the fabric of space and time swirls in a cosmic whirlpool around a dead star has confirmed yet another prediction from Einstein's theory of general relativity, a new study finds.

    Space-time is swirling around a dead star, proving Einstein right again : Read more

    The observations and model fit with GR seems very good. Here is another report on the frame dragging in this binary system. White Dwarf’s Whirlwind Spin Drags Spacetime
    The report cited here provides a bit more detail. "The Parkes and UTMOST radio telescopes in Australia collected precise measurements of the neutron star’s radio pulses over almost 20 years. Krishnan and his colleagues used the pulse arrival times to reconstruct the slow change in the pulsar’s orbit, finding that frame-dragging had shifted the orbit by some 7 kilometers per year...The new result not only provides the first confirmation of Lense-Thirring precession beyond Earth’s orbit; it also sheds light on the binary’s history."

    Looks like another test of Einstein GR that passes :)
    Reply
  • Nick
    Space.com has a flimsy definition of proof. Even the properties of neutron stars are full of assumptions that aren't proven. Pass a test? Yes. Fail to disprove? Yes. Proof? No! The goal of a good scientist should not be to try to prove anything, but to disprove in search of new ideas.
    Reply
  • Stephen J. Bauer
    Good review of current understanding for of gravity drag, a.k.a. space-time churn. The space warp is a consequence of Einstein's general theory of relativity, which describes gravity as a curvature in space produced by objects sitting in it. It also implies that a rotating mass will drag space around it like a spinning top placed in treacle - an effect known as the Lense-Thirring effect, or more commonly as 'frame-dragging'.

    The alternative significance of this activity is that is demonstrates the concept that matter is a marriage of ordinary matter (positive density mass) and dark matter (negative density mass). Where dark matter acts as the insulating cushion for ordinary matter from the expanding effects of dark energy, it provides an embrace that instantiate the force of gravity.

    This consideration is better understood by thinking of gravity a bit differently. Where the universe's total energy is broken down to as 68% dark energy, 27% mass-energy via dark matter, and 5% mass-energy via ordinary matter, the percentage of energy distribution suggests a differing evolution. If we assume that dark energy, being the largest distribution of total energy, represents the foundation for space-time and provides for a net zero inclusion of matter as a whole, then it starts as 100% of the total energy. Upon the advent of matter, as a whole, the distribution of total energy is shared among the universal components. It is a process that maintains the concept of retaining a zero sum net gain, by redistributing this total energy with the complementarily paired positive and negative density matter. This evolutionary distribution also takes on other aspects of universal purpose: dark energy being responsible for the increasing universal expansion of the newly created matter, dark matter insulating the ordinary matter from being torn apart within its dark energy medium, and ordinary matter building and evolving into whatever it can. In effect, dark matter is the 'force' created to insulate ordinary matter, or positive density mass, by warping the space-time fabric of dark energy away from its complementary partner, ordinary matter.

    The dynamic of space-time dimensional variance is built upon an understanding of acceleration over velocity. As we understand the special relativity theory of special relativistic time dilation, there is an order in which acceleration measures the speed of relative velocity; the faster the velocity between two orders of spatial distance, the greater the time dilation between them. What we are measuring in the case of our expanding universe is a uniform time dilation pattern from any point in space to any other point in space. If anything, this proposes that there is an increase in the effect of dark energy on positive density matter as negative density matter increases.

    If you're interested in exploring this concept more, please review the alternative theories presented in the book, 'The Evolutioning of Creation: Volume 2', or even the ramifications of these concepts in the sci-fi fantasy adventure, 'Shadow-Forge Revelations'. The theoretical presentation brings forth a variety of alternative perspectives on the aspects of existence that form our reality.
    Reply
  • Western Sage
    I agree with the concern that the object with the smaller mass, the neutron star, should be orbiting the object with the larger mass, the pulsar. Does the author know something we don't? Or is this just a misstatement?
    Reply