New theoretical research finds that it’s impossible to form a black hole with the energy of light particles alone, poking a hole in Einstein’s theory of general relativity.
Category: cosmology – Page 88
Can quantum particles mimic gravitational waves?
When two black holes collide, space and time shake and energy spreads out like ripples in a pond. These gravitational waves, predicted by Einstein in 1916, were observed for the first time by the Laser Interferometer Gravitational-Wave Observatory (LIGO) telescope in September 2015.
Five new ways to catch gravitational waves — and the secrets they’ll reveal
Innovative techniques being developed to detect gravitational waves beyond the current capabilities of laser interferometers like LIGO and Virgo.
That rare bright spot looks set to become brighter.
All of the more than 100 gravitational-wave events spotted so far have been just a tiny sample of what physicists think is out there. The window opened by LIGO and Virgo was rather narrow, limited mostly to frequencies in the range 100–1,000 hertz. As pairs of heavy stars or black holes slowly spiral towards each other, over millions of years, they produce gravitational waves of slowly increasing frequency, until, in the final moments before the objects collide, the waves ripple into this detectable range. But this is only one of many kinds of phenomenon that are expected to produce gravitational waves.
LIGO and Virgo are laser interferometers: they work by detecting small differences in travel time for lasers fired along perpendicular arms, each a few kilometres long. The arms expand and contract by minuscule amounts as gravitational waves wash over them. Researchers are now working on several next-generation LIGO-type observatories, both on Earth and, in space, the Laser Interferometer Space Antenna; some have even proposed building one on the Moon1. Some of these could be sensitive to gravitational waves at frequencies as low as 1 Hz.
A higher-dimensional model can help explain cosmic acceleration without dark energy
Dark energy remains among the greatest puzzles in our understanding of the cosmos. In the standard model of cosmology called the Lambda-CDM, it is accounted for by adding a cosmological constant term in Einstein’s field equation first introduced by Einstein himself. This constant is very small and positive and lacks a complete theoretical understanding of why it has such a tiny value. Moreover, dark energy has some peculiar features, such as negative pressure and does not dilute with cosmic expansion, which makes at least some of us uncomfortable.
The Answer to the Final Parsec Problem Is Suddenly Within Reach. And It May Change Science
A discrepancy between mathematics and physics has plagued astrophysicists’ understanding of how supermassive black holes merge, but dark matter may have the answer.
HUXLEY: THE ORACLE Trailer (Official)
Official trailer for HUXLEY: THE ORACLE, the next prequel story in Ben Mauro’s post apocalyptic sci-fi universe! The Oracle Empire is at the height of its power, Max is a young recruit in the Ronin army sent out on an important mission deep into the wasteland with his team. What they discover could change the course of history forever. The AI wars have begun. Directed by Syama Pedersen of ‘ASTARTES’ Warhammer 40k and the renown UNIT IMAGE animation studio, dive deeper into the world of HUXLEY in this exciting new story.
If you would like to know more, read the original graphic novel and the new Oracle prequel book that tells the story glimpsed in the trailer. Available worldwide for pre-order from Thames \& Hudson. https://vol.co/collections/the-oracle.
Official site: https://www.huxleysaga.com
During the cosmic dawn, space wasn’t as empty as it seems today
Have you ever wondered what the universe looked like after the Big Bang when it was still in its infancy, a mere billion years old? With NASA’s new Nancy Grace Roman Space Telescope, we’re about to get a glimpse of the cosmic dawn.
This cosmic time machine is set to explore an era known as the cosmic dawn, a significant transition when the universe went from a foggy opacity to the stunning, star-filled expanse we observe today.
Behind this ambitious project is the esteemed astrophysicist Michelle Thaller from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.