A triple star system puts Einstein’s theory of gravity to the test.
The Gilded Age
The collision of neutron stars causes a galaxy to enter a gilded age.
How Do You Weigh A Neutron Star?
New work in Science Advances has found an interesting way to determine the mass of a type of neutron star known as a pulsar.
Highland Fling
Yesterday I talked about millisecond pulsars, and the way in which they might gain such rapid rotation. Another property of millisecond pulsars is that they demonstrate very clearly that pulsars are neutron stars. It all has to do with their rapid rotation and the physics of centripetal (or centrifugal) force.
Eat and Run
A millisecond pulsar is a neutron star that is rotating about 600 to 700 times a second. Because of their strong magnetic fields, they produce strong beams of radio energy from the regions of their magnetic poles, and as they rotate these beams can point in our direction. As a result, we observe these neutron stars as radio bursts that pulse every 1 – 10 milliseconds. Hence their name.
Flight Delay
It’s a well known law of physics that the speed of light (in a vacuum) is always the same, regardless of your frame of reference (essentially your vantage point). But this isn’t entirely true. It actually depends on how you define “speed”.
Magnificent Seven
In the 1990s the ROSAT x-ray observatory made an all-sky survey. By 2001, seven soft x-ray sources were found from the survey data, and shown to be neutron stars. They came to be known as the magnificent seven.
Diamond Sky
A neutron star is the remnant of a large supernova. When a large star explodes, a remnant of its core is compressed so tightly that the electrons are squeezed into protons, resulting in a mass of neutrons. A neutron star typically has a mass of about 2 solar masses, but it is only about 12 kilometers in diameter. Imagine taking two suns and squeeze it into the size of a small city, and you get the idea of how incredibly dense these objects are.
A Distant Noise
A while back I wrote about a phenomena known as fast radio bursts (FRBs). These short bursts of radio energy have been a bit of a puzzle. On the one hand they they have all the appearance of being astronomical in nature. For one thing, the frequencies of the signal are spread out so that higher frequencies arrive before lower ones. This is known as dispersion, and is an indicator having traveled through the interstellar medium. On the other hand, the signals are unusually strong, and their short duration is similar to radio interference from sources on Earth. They’ve also only been detected at one radio telescope (the Parkes radio telescope in Australia). That is, until now.
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