A closer look at gravitational wave data reveals 10 overlooked mergers, including one between black holes that probably found each other late in life.
The received view in physics is that the direction of time is provided by the second law of thermodynamics, according to which the passage of time is measured by ever-increasing disorder in the universe. This view, Julian Barbour argues, is wrong. If we reject Newton’s faulty assumptions about the existence of absolute space and time, Newtonian dynamics can be shown to provide a very different arrow of time. Its direction, according to this theory, is given by the increase in the complexity and order of a system of particles, exactly the opposite of what the received view about time suggests.
Two of the most established beliefs of contemporary cosmology are that the universe is expanding and that the direction of the arrow of time in the universe is defined by ever-increasing disorder (entropy), as described by the second law of thermodynamics. But both of these beliefs rest on shaky ground. In saying that the universe is expanding, physicists implicitly assume its size is measured by a rod that exists outside the universe, providing an absolute scale. It’s the last vestige of Newton’s absolute space and should have no place in modern cosmology. And in claiming that entropy is what gives time its arrow, physicists uncritically apply the laws of thermodynamics, originally discovered through the study of steam engines, to the universe as a whole. That too needs to be questioned.
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Scientists at Nagoya University in Japan claim to have discovered dark matter that dates back 12 billion years ago, which would make it the earliest observation of the hypothetical substance to date.
Their findings — as detailed in a new paper published in the journal Physical Review Letters — could potentially offer some tantalizing answers about the nature of the universe.
Until now, observations of dark matter only went as far back as ten billion years. Any further than that, and the light was too faint to observe.
Outer space is already an essential part of America’s ability to fight wars. Our military depends on satellites for many things, such as communications, reconnaissance and targeting information. See more in Season 4, Episode 8, “Space Wars.”
#TheUniverse.
Continue reading “The Universe: Space Weapons Prepare for War (S4, E8) | Full Episode | History” »
A new hypothesis proposes that a large fraction of dark matter may be bound up inside tight balls the size of Neptune — so-called dark matter planets.
What remains are mostly neutron stars or black holes. And now, Hubble seems to have documented the instant when a supernova blinked out — implying that it captured the moment a black hole took control.
While some supernova explosions, such as SN 1,054, are violent and leave clouds of debris for thousands of years (a.k.a. nebula), the star in question seems to have exploded and then had all its gas pulled back into the black hole at the core. This may occur if the star’s core collapse is very big. Rather than exploding, the gas falls into the star’s core.
Over the past few years, astronomers have become aware of some shocking new properties of black holes.
As it turned out, they not only mercilessly consume and destroy everything that falls into them.
NASA’s James Webb Space Telescope has peered into the chaos of the Cartwheel Galaxy, revealing new details about star formation and the galaxy’s central black hole. Webb’s powerful infrared gaze produced this detailed image of the Cartwheel and two smaller companion galaxies against a backdrop of many other galaxies.
Scientists used a fossil relic left over from the Big Bang to perform the earliest detection of dark matter ever.
Astronomers used the cosmic microwave background, radiation left over from just after the Big Bang, to conduct the earliest ever detection of dark matter.
