Space and astronomy news
Thanks to the Hubble Space Telescope, we all have a vivid image of the Crab Nebula emblazoned in our mind’s eyes. It’s the remnant of a supernova explosion Chinese astronomers recorded in 1056. However, the Crab Nebula is more than just a nebula; it’s also a pulsar.
The Crab Pulsar pulsates in an unusual ‘zebra’ pattern, and an astrophysicist at the University of Kansas thinks he’s figured out why.
Continue reading “The Strange Pulsar at the Center of the Crab Nebula”
When massive stars detonate as supernovae, they leave often behind a pulsar. These fast rotating stellar corpses have fascinated scientists since their discovery in 1967. One nearby pulsar turns 174 times a second and now, its size has been precisely measured. An instrument on board the International Space Station was used to measure x-ray pulses from the star. A supercomputer was then used to analyse its properties and found it was 1.4 times the mass of the Sun and measured only 11.4 km across!
Continue reading “A Close Pulsar Measures 11.4 km Across”
Pulsars are extreme objects. They’re what’s left over when a massive star collapses on itself and explodes as a supernova. This creates a neutron star. Neutron stars spin, and some of them emit radiation. When they emit radiation from their poles that we can see, we call them pulsars.
Continue reading “Spider Pulsars are Tearing Apart Stars in the Omega Cluster”
Pulsars are known for their regularity and stability. These fast-rotating neutron stars emit radio waves with such consistent pulses that astronomers can use them as a kind of cosmic clock. But recently a pulsar emitted gamma rays with tremendous energy. The gamma rays were the most energetic photons ever observed, with energies of more than 20 teraelectronvolts, and astronomers are struggling to understand how that’s possible. The results were published in Nature Astronomy, which describes the burst of gamma rays emanating from the Vela Pulsar.
Continue reading “A Pulsar Suddenly Threw Out Radiation 200 Times More Energetic”
Recently astronomers have been able to associate two seemingly unrelated phenomena: an explosive event known as a fast radio burst and the change in speed of a spinning magnetar. And now new research suggests that the cause of both of these is the destruction of an asteroid by a magnetar.
Continue reading “Magnetar Glitches, Fast Radio Bursts, And…Asteroids???”
Pulsars are rotating neutron stars aligned with Earth in just such a way that the energy radiated from their magnetic poles sweeps across us with each rotation. From this, we see a regular pulse of radio light, like a cosmic lighthouse. The fastest pulsars can rotate very quickly, pulsing hundreds of times per second. These are known as millisecond pulsars.
Continue reading “Astronomers Find the Fastest Spider Pulsar, Filling in the Missing Link in Their Evolution”
The Theory of General Relativity (GR), proposed by Einstein over a century ago, remains one of the most well-known scientific postulates of all time. This theory, which explains how spacetime curvature is altered in the presence of massive objects, remains the cornerstone of our most widely-accepted cosmological models. This should come as no surprise since GR has been verified nine ways from Sunday and under the most extreme conditions imaginable. In particular, scientists have mounted several observation campaigns to test GR using Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way.
Last year, the Event Horizon Telescope (EHT) – an international consortium of astronomers and observatories – announced they had taken the first images of Sag A*, which came just two years after the release of the first-ever images of an SMBH (M87). In 2014, the European members of the EHT launched another initiative known as BlackHoleCam to gain a better understanding of SMBHs using a combination of radio imaging, pulsar observations, astrometry, and GR. In a recent paper, the BHC initiative described how they tested GR by observing pulsars orbiting Sgr A*.
Continue reading “Pulsars Could Help Map the Black Hole at the Center of the Milky Way”
Life’s not too good if you’re the companion of a black widow. Here on Earth, spiders by that name feast on their smaller significant others after mating. Out in space, some weird objects do the same thing to their closeby neighbors. They’re rapidly spinning neutron stars that slowly destroy their companion stars with powerful outflows of high-energy particles. A team at the University of California Berkeley is studying one of these so-called “black widow pulsars”, called PSR J0952-0607. Thanks to its hefty appetite, it shredded and consumed nearly all of its stellar companion. That eating spree made it the heaviest known neutron star to date.
Continue reading “The Heaviest Neutron Star Ever Seen Got There by Feasting on its Companion”
The Milky Way Galaxy has its share of oddities, from black holes and magnetars to luminous blue variable stars and strange new worlds. But, have you ever heard of a “black widow binary?” Not exactly an easy name to wrap your head around, especially if you’re afraid of spiders. But, these things actually exist in our galaxy and they’re fascinating.
Continue reading “A Pulsar and Star are Orbiting Each Other Every 62 Minutes. The Fastest “Black Widow” Binary Ever Seen”
Ever hear of the Galactic Center GeV Excess? No, it’s not a cosmic rock band, although that’s a great name for one. Actually, it’s what astronomers call a super-high rate of gamma-ray radiation coming from the heart of our Milky Way Galaxy. Since this Galactic Center Excess was first detected in 2009, people thought it might be a signature of dark matter annihilating itself in mass quantities. But, as with any unexplained phenomenon in space, others disagreed. It could also have something to do with Sagittarius A*, the galaxy core’s own supermassive black hole. Or, it might be some other kind of strange burst event. Now, an astronomer at the Australian National University suggests that rapidly spinning neutron stars may be the culprits behind this high-energy galactic mystery.
Continue reading “Pulsars Could Explain the Excess of Gamma Radiation Coming from the Center of the Milky Way”