Pulsar Disappears After Space-Time Warp Measured

Scientists have measured the space-time warp in the gravity of binary pulsar system J1906 and determined the mass of its neutron star before the pulsar vanished from view.

A binary pulsar system is comprised of a pulsar that is orbiting a binary companion which is usually a white dwarf or neutron star. In the case of Binary Pulsar J1906, the scientists have measured the solar mass of the accompanying neutron star to be 1.32 solar mass with a sphere only 10 kilometers (6.21 miles) across.

J1906 is the youngest double neutron star system whose mass has been measured.

The spin axis of the pulsar wobbles like a spinning top. Since the distance of the two neutron stars in J1906 is very close and each star weighs more than the Sun, the space-time between the stars is curved which affects the pulsar's spin axis. The wobble has been so much that the pulsar's beams no longer hit the Earth, making it disappear from sight.

It is expected that the pulsar will be visible again in 160 years.

A pulsar is a neutron star that formed when a massive star's core is compressed during a supernova. The supernova collapses the star's core and forms the neutron star. Pulsars are extermely dense and highly magnetized. They rotate and emit a beam of electromagnetic radiation which is picked up as radio waves in the form of pulses. The name pulsar is abbreviated from the term "pulsating star".

Gravitational Waves Give Insight To Growth of Supermassive Black Holes

CSIRO Parkes Radio Telescope

Scientists are looking at gravitational waves to understand the growth of supermassive black holes.

Black holes are regions in space where gravity is so strong that nothing, not even light, can resist its pull. It is believed that every galaxy has a supermassive black hole (SMBH) in its center.

Gravitational waves can best be described as small waves or ripples that travel through the fabric of space-time. It is like putting a bowling bowl on a mattress and rolling it forward. The indentations surrounding the bowling ball as it rolls can be described as a gravitational wave.

Einstein theorized that similar to the mattress, the dimension of space-time warps and curves as planets and other objects of big masses move along it. These curvatures generate ripples (waves) in space-time that travel outward at the speed of light and diminishes in energy as it goes further out.

Although gravitational waves have not yet been directly discovered, there have been indirect observations of its existence using radio signals from a pulsar.

In this latest study, scientists believe that by studying the connection between the strength of a gravitational wave and how two colliding supermassive blackholes behave (their mass, distance between each other and how often it spirals and merge), it will help explain the growth of black holes.

White Dwarf Star Orbiting A Pulsar Discovered By ESO's VLT

Astronomers have used ESO’s Very Large Telescope, along with radio telescopes around the world, to find and study a bizarre stellar pair consisting of the most massive neutron star confirmed so far, orbited by a white dwarf star. This strange new binary allows tests of Einstein’s theory of gravity — general relativity — in ways that were not possible up to now. So far the new observations exactly agree with the predictions from general relativity and are inconsistent with some alternative theories. The results will appear in the journal Science on 26 April 2013.

Scientists using the European Southern Observatory's Very Large Telescope (VLT) has discovered an unusual pairing; a white dwarf star orbiting a neutron star (PSR J0348+0432). The neutron star is a pulsar around 20 kilometres across but is two times heavier than the Sun. This discovery and the observation of how the two stellar objects behave is how Einstein's Theory of General Relativity predicted it would behave.

A white dwarf star is a small star which is very dense and is mostly made up of electron-degenerate matter. It is a star that has reached the end of its normal life cycle and has stopped nuclear fusion (although some fusion reactions happen and can still generate energy). A white dwarf star may be as big as the Earth but has the same mass as that of the Sun.

A pulsar is a neutron star that is formed when a massive star's core is compressed during a super nova. This event collapses the core and forms the neutron star. Pulsars are extermely dense and highly magnetized. They rotate and emit a beam of electromagnetic radiation. This radiation is picked up as radio waves in the form of pulses. The name pulsar is abbreviated from the term "pulsating star".