Image: Guillaume Voisin
An international group of scientists confirmed one of the basic principles of the theory of relativity, called the principle of equivalence of gravitational forces and inertia. According to this concept, in a homogeneous gravitational field all motions and interactions occur in the same way as in a system moving with uniform acceleration in the absence of external gravitational field. Article with results was published in the journal Astronomy & Astrophysics.
A new study has shown that the principle is true for objects with strong gravity, such as a neutron star. With the radio telescope Nancay (France) the researchers conducted observations of the pulsar PSR J0337+1715 with the weight equal to 1.44 solar masses, and a diameter of only 25 kilometers. This object is in a triple system with two white dwarfs with a smaller mass and weaker gravitational field.
The basis of the principle of equivalence is the observation that bodies with different masses fall in the same gravitational field with the same acceleration. This is called the universality of free fall (eng. universality of free fall), or the Galileo principle. However, scientists did not know whether the principle for bodies with extremely strong gravitational field.
A pulsar emits a narrow beam of radio waves, which is detected by a radio telescope during each revolution of the object. When you move the pulsar check signal is shifted, which allows scientists to accurately determine the motion of the neutron star along the orbit. The pulsar rotates around one of the white dwarfs, and together they rotate around a second white dwarf. Thus, scientists were able to determine the acceleration of the neutron star and the object with a smaller mass relative to the third object in the system.
It turned out that the extreme gravity of the pulsar cannot differ by more than 1.8 parts per million from the forecast of General theory of relativity (with a confidence level of 95 percent). This result is the most precise proof that the universality of free fall is valid even in the presence of an object whose mass is mostly due to its own gravitational field.
Video, photo All from Russia.