Why Pulsars Are So Bright

When pulsars were first discovered in 1967, their rhythmic radio-wave pulsations were a mystery. Some thought their radio beams must be of extraterrestrial origin.

We’ve learned a lot since then. We know that pulsars are magnetized, rotating neutrons stars. We know that they rotate very rapidly, with their magnetic poles sending sweeping beams of radio waves out into space. And if they’re aimed the right way, we can “see” them as pulses of radio waves, even though the radio waves are steady. They’re kind of like lighthouses.

But the exact mechanism that creates all of that electromagnetic radiation has remained a mystery.

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How the World’s Biggest Radio Telescope Could be Used to Search for Aliens

In 2016, China’s Five-hundred-meter Aperture Spherical radio Telescope – the largest single-aperture radio telescope in the world – gathered its first light. Since then, the telescope has undergone extensive testing and commissioning and officially went online in Jan of 2020. In all that time, it has also been responsible for multiple discoveries, including close to one hundred new pulsars.

According to a recent study by an international team of scientists and led by the Chinese Academy of Sciences (CAS) suggests that FAST might have another use as well: the search for extraterrestrial intelligence (SETI)! Building on their collaboration with the non-profit science organization Breakthrough Initiatives, the authors of the study highlight the ways in which FAST could allow for some novel SETI observations.

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A Star Has Been Found That Pulsates, But Only on One Side

In the 17th century, astronomers witnessed many stellar events that proved that the starry sky was not “fixed and eternal.” This included stars whose brightness varied over time – aka. “variable stars.” By the 20th century, many variable stars had been cataloged and astronomers have discerned subclasses of them as well – notably, stars that swell and shrink, known as pulsating variables.

In all cases, these variable stars were found to have rhythmic pulsations that were visible from all sides. But a recent discovery by an international team has confirmed that there are variable stars that can pulse from only one side. This pulsating star, part of a system known as HD 74423, is located about 1,500 light-years from Earth and is the first of its kind to be found.

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Dark Matter Could Be A Source of Gamma Rays Coming from the Center of the Milky Way

There’s a lot of mysterious goings-on at the center of the Milky Way. The supermassive black hole that resides there is chief among them. But there’s another intriguing puzzle there: an unexpected spherical region of intense gamma ray emissions.

A new study suggests that dark matter could be behind those emissions.

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The Most Massive Neutron Star has been Found. It’s ALMOST the Most Massive Neutron Star That’s Even Possible

Neutron stars are the end-state of massive stars that have spent their fuel and exploded as supernovae. There’s an upper limit to their mass, because a massive enough star won’t become a neutron star; it’ll become a black hole. But finding that upper mass limit, or tipping point, between a star that becomes a black hole and one that becomes a neutron star, is something astronomers are still working on.

Now a new discovery from astronomers using the National Science Foundation’s (NSF) Green Bank Telescope (GBT) have found the most massive neutron star yet, putting some solid data in place about the so-called tipping point.

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NASA is building up a map of the entire sky seen in X-rays, line by line with its NICER experiment

In June of 2017, NASA’s Neutron Star Interior Composition Explorer (NICER) was installed aboard the International Space Station (ISS). The purpose of this instrument is to provide high-precision measurements of neutron stars and other super-dense objects that are on the verge of collapsing into black holes. NICER is also be the first instrument designed to test technology that will use pulsars as navigation beacons.

Recently, NASA used data obtained from NICER’s first 22 months of science operations to create an x-ray map of the entire sky. What resulted was a lovely image that looks like a long-exposure image of fire dancers, solar flare activity from hundreds of stars, or even a visualization of the world wide web. But in fact, each bright spot represents an x-ray source while the bright filaments are their paths across the night sky.

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Astronomers are Using NASA’s Deep Space Network to Hunt for Magnetars

Right, magnetars. Perhaps one of the most ferocious beasts to inhabit the cosmos. Loud, unruly, and temperamental, they blast their host galaxies with wave after wave of electromagnetic radiation, running the gamut from soft radio waves to hard X-rays. They are rare and poorly understood.

Some of these magnetars spit out a lot of radio waves, and frequently. The perfect way to observe them would be to have a network of high-quality radio dishes across the world, all continuously observing to capture every bleep and bloop. Some sort of network of deep-space dishes.

Like NASA’s Deep Space Network.  

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An Extremely Rare Gamma Ray Emitting Neutron Star Binary Has Been Found

Neutron stars are one of the most fascinating astronomical objects in the known Universe. In addition to being the densest type of star (with the possible exception of quark stars), they have also been known to form binary pairs with massive stars. To date, only 39 such systems have been discovered, and even fewer have been detected that were composed of a massive star and a very high energy (VHE) gamma-ray neutron star.

To date, only two of these systems have been found, the second of which was discovered just a few years ago by a team of international astronomers known as the Very Energetic Radiation Imaging Telescope Array System (VERITAS) collaboration. In addition to being a rare find, the discovery was also very fortunate, since the unusual behavior they observed coming from this system will not be happening again until 2067.

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