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Archive for the ‘physics’ category: Page 9

Sep 19, 2019

Pulsating gamma rays from neutron star rotating 707 times a second

Posted by in categories: physics, space

An international research team led by the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover has discovered that the radio pulsar J0952-0607 also emits pulsed gamma radiation. J0952-0607 spins 707 times in one second and is second in the list of rapidly rotating neutron stars. By analyzing about 8.5 years worth of data from NASA’s Fermi Gamma-ray Space Telescope, LOFAR radio observations from the past two years, observations from two large optical telescopes, and gravitational-wave data from the LIGO detectors, the team used a multi-messenger approach to study the binary system of the pulsar and its lightweight companion in detail. Their study published in the Astrophysical Journal shows that extreme pulsar systems are hiding in the Fermi catalogs and motivates further searches. Despite being very extensive, the analysis also raises new unanswered questions about this system.

Pulsars are the compact remnants of stellar explosions which have strong magnetic fields and are rapidly rotating. They emit radiation like a cosmic lighthouse and can be observable as radio pulsars and/or gamma-ray pulsars depending on their orientation towards Earth.

Sep 17, 2019

Researchers discover massive neutron star that tests the limits of physics

Posted by in categories: cosmology, physics

Astronomers have detected the most massive neutron star ever, and it almost shouldn’t even exist.

Neutron stars are the smallest in the universe, with a diameter comparable to the size of a city like Chicago or Atlanta. They are the leftover remnants of supernovae. But they are incredibly dense, with masses bigger than that of our sun. So think of the sun, compressed into a major city.

In the case of the newly detected neutron star, dubbed J0740+6620, it’s 333,000 times the mass of the Earth and 2.17 times the mass of the sun. But the star is only about 15 miles across. It’s 4,600 light-years from Earth.

Sep 17, 2019

Posthuman Times

Posted by in categories: biological, physics

Humanist and technoscientific notions of progress have been (mis)used to classify human and nonhuman life forms into hierarchical categories, thereby reducing the complexities of life stories into a linear account of development and innovation. At the same time, critical reflections on key concepts of modernist, Eurocentric and industry-driven concepts of time and historicity and, more forcefully perhaps, new findings in evolutionary biology and physics, have produced alternative narratives, sometimes with a reconsideration of premodern understandings of temporality like, for example, Gilles Deleuze ’s rereading of Leibniz in The Fold.[1] The modernist conception of History (with a capital H) as both an empirical reality and a specific disciplinary and disciplining knowledge [2] has thus become just one possible manifestation within a plurality of histor ies conditioned by socio-cultural particularities that honour the experience of bodies that, voluntarily or not, live outside re/productive timelines, for example.

An increasing number of researchers as well as artists are no longer interested in the taking and making time and space as human universals but in genealogies, intersections, “multiple modernities”[3] and the coexistence of non-simultaneous phenomena in the era of globalization, asymmetrical power relations and technoculture. Moreover, post-anthropocentric thinking and creativity, fostered in posthumanist discourse (including new materialism, speculative realism, object-oriented ontology, neocybernetic systems theory, etc.), also increasingly attends to nonhuman temporalities and how these are entangled, often in conflicting ways, with human time. Such considerations include the vexing question of how emancipatory goals of progressive social trans/formation and justice can be envisaged, let alone obtained, if we can no longer ground our theories and political practices in enlightened narratives of humanist progress and liberation.

Sep 16, 2019

Real Artificial Gravity for SpaceX’s Starship

Posted by in categories: physics, space travel

Despite the many, many problems we face in the world today, it is still an exciting time to be alive! As we speak, mission planners and engineers are developing the concepts that will soon take astronauts on voyages beyond Low Earth Orbit (LEO) for the first time in almost fifty years. In addition to returning to the Moon, we are also looking further afield to Mars and other distant places in the Solar System.

This presents a number of challenges, not the least of which are the effects of prolonged exposure to radiation and microgravity. And whereas there are many viable options for protecting crews from radiation, gravity remains a bit of a stumbling block. To address this, Youtuber smallstars has proposed a concept that he calls the Gravity Link Starship (GLS), a variation of SpaceX’s Starship that will be able to provide its own artificial gravity.

Continue reading “Real Artificial Gravity for SpaceX’s Starship” »

Sep 16, 2019

Einstein’s black holes are not the black holes we see in reality

Posted by in categories: cosmology, physics

Field notes from space-time | We’re only just grasping how cosmic black holes and Einstein’s theories relate – and that deepens our sense of wonder, says Chanda Prescod-Weinstein.

Sep 16, 2019

Gravity waves from a ringing black hole support the no-hair theorem

Posted by in categories: cosmology, physics

A new study of gravitational waves from merging black holes agrees with the predictions of the general theory of relativity.

Sep 14, 2019

Gravitational waves detected for first time from newly born black hole: Study

Posted by in categories: cosmology, physics

Researchers have, for the first time, detected the gravitational waves from a newly born black hole, and found that the ringing pattern of the waves predicts the cosmic body’s mass and spin, providing more evidence for Einstein’s General Theory of Relativity.

The study, published in the journal Physical Review Letters, increases the possibility that black holes exhibit only three observable properties – mass, spin, and electric charge.

All other properties, the study noted, could be swallowed up by the black hole itself, and are unobservable.

Sep 14, 2019

Trampoline mirror may push laser pulse through fabric of the Universe

Posted by in categories: physics, space

Simply changing a mirror may allow physicists to poke a hole in the universe.

Sep 13, 2019

Bringing light to a halt: Physicists freeze motion of light for a minute

Posted by in category: physics

Circa 2013 o.o


Physicists have been able to stop something that has the greatest possible speed and that never really stops: light. A decade ago, physicists stopped it very for a short moment. In recent years, this extended towards stop times of a few seconds for simple light pulses in extremely cold gases and special crystals. But now the same researchers extended the possible duration and applications for freezing the motion of light considerably. The physicists stopped light for about one minute. They were also able to save images that were transferred by the light pulse into the crystal for a minute — a million times longer than previously possible.

Close.

Sep 10, 2019

Are black holes made of dark energy?

Posted by in categories: cosmology, information science, physics

Two University of Hawaii at Manoa researchers have identified and corrected a subtle error that was made when applying Einstein’s equations to model the growth of the universe.

Physicists usually assume that a cosmologically large system, such as the , is insensitive to details of the small systems contained within it. Kevin Croker, a postdoctoral research fellow in the Department of Physics and Astronomy, and Joel Weiner, a faculty member in the Department of Mathematics, have shown that this assumption can fail for the compact objects that remain after the collapse and explosion of very large .

“For 80 years, we’ve generally operated under the assumption that the universe, in broad strokes, was not affected by the particular details of any small region,” said Croker. “It is now clear that general relativity can observably connect collapsed stars—regions the size of Honolulu—to the behavior of the universe as a whole, over a thousand billion billion times larger.”

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